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Sample records for yeast detoxifies lignocellulosic

  1. Metabolic engineering of yeast for lignocellulosic biofuel production.

    Science.gov (United States)

    Jin, Yong-Su; Cate, Jamie Hd

    2017-12-01

    Production of biofuels from lignocellulosic biomass remains an unsolved challenge in industrial biotechnology. Efforts to use yeast for conversion face the question of which host organism to use, counterbalancing the ease of genetic manipulation with the promise of robust industrial phenotypes. Saccharomyces cerevisiae remains the premier host for metabolic engineering of biofuel pathways, due to its many genetic, systems and synthetic biology tools. Numerous engineering strategies for expanding substrate ranges and diversifying products of S. cerevisiae have been developed. Other yeasts generally lack these tools, yet harbor superior phenotypes that could be exploited in the harsh processes required for lignocellulosic biofuel production. These include thermotolerance, resistance to toxic compounds generated during plant biomass deconstruction, and wider carbon consumption capabilities. Although promising, these yeasts have yet to be widely exploited. By contrast, oleaginous yeasts such as Yarrowia lipolytica capable of producing high titers of lipids are rapidly advancing in terms of the tools available for their metabolic manipulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Lignocellulosic ethanol production by starch-base industrial yeast under PEG detoxification

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    Liu, Xiumei; Xu, Wenjuan; Mao, Liaoyuan; Zhang, Chao; Yan, Peifang; Xu, Zhanwei; Zhang, Z. Conrad

    2016-02-01

    Cellulosic ethanol production from lignocellulosic biomass offers a sustainable solution for transition from fossil based fuels to renewable alternatives. However, a few long-standing technical challenges remain to be addressed in the development of an economically viable fermentation process from lignocellulose. Such challenges include the needs to improve yeast tolerance to toxic inhibitory compounds and to achieve high fermentation efficiency with minimum detoxification steps after a simple biomass pretreatment. Here we report an in-situ detoxification strategy by PEG exo-protection of an industrial dry yeast (starch-base). The exo-protected yeast cells displayed remarkably boosted vitality with high tolerance to toxic inhibitory compounds, and with largely improved ethanol productivity from crude hydrolysate derived from a pretreated lignocellulose. The PEG chemical exo-protection makes the industrial S. cerevisiae yeast directly applicable for the production of cellulosic ethanol with substantially improved productivity and yield, without of the need to use genetically modified microorganisms.

  3. Maleic acid treatment of biologically detoxified corn stover liquor.

    Science.gov (United States)

    Kim, Daehwan; Ximenes, Eduardo A; Nichols, Nancy N; Cao, Guangli; Frazer, Sarah E; Ladisch, Michael R

    2016-09-01

    Elimination of microbial and enzyme inhibitors from pretreated lignocellulose is critical for effective cellulose conversion and yeast fermentation of liquid hot water (LHW) pretreated corn stover. In this study, xylan oligomers were hydrolyzed using either maleic acid or hemicellulases, and other soluble inhibitors were eliminated by biological detoxification. Corn stover at 20% (w/v) solids was LHW pretreated LHW (severity factor: 4.3). The 20% solids (w/v) pretreated corn stover derived liquor was recovered and biologically detoxified using the fungus Coniochaeta ligniaria NRRL30616. After maleic acid treatment, and using 5 filter paper units of cellulase/g glucan (8.3mg protein/g glucan), 73% higher cellulose conversion from corn stover was obtained for biodetoxified samples compared to undetoxified samples. This corresponded to 87% cellulose to glucose conversion. Ethanol production by yeast of pretreated corn stover solids hydrolysate was 1.4 times higher than undetoxified samples, with a reduction of 3h in the fermentation lag phase. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Yeast derived from lignocellulosic biomass as a sustainable feed resource for use in aquaculture.

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    Øverland, Margareth; Skrede, Anders

    2017-02-01

    The global expansion in aquaculture production implies an emerging need of suitable and sustainable protein sources. Currently, the fish feed industry is dependent on high-quality protein sources of marine and plant origin. Yeast derived from processing of low-value and non-food lignocellulosic biomass is a potential sustainable source of protein in fish diets. Following enzymatic hydrolysis, the hexose and pentose sugars of lignocellulosic substrates and supplementary nutrients can be converted into protein-rich yeast biomass by fermentation. Studies have shown that yeasts such as Saccharomyces cerevisiae, Candida utilis and Kluyveromyces marxianus have favourable amino acid composition and excellent properties as protein sources in diets for fish, including carnivorous species such as Atlantic salmon and rainbow trout. Suitable downstream processing of the biomass to disrupt cell walls is required to secure high nutrient digestibility. A number of studies have shown various immunological and health benefits from feeding fish low levels of yeast and yeast-derived cell wall fractions. This review summarises current literature on the potential of yeast from lignocellulosic biomass as an alternative protein source for the aquaculture industry. It is concluded that further research and development within yeast production can be important to secure the future sustainability and economic viability of intensive aquaculture. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  5. Thermotolerant Yeasts for Bioethanol Production Using Lignocellulosic Substrates

    Science.gov (United States)

    Pasha, Chand; Rao, L. Venkateswar

    glucose without a physical and chemical pre-treatment. The pre-treatment processes normally applied on the different substrates are acidic hydrolysis, steam explosion and wet oxidation. A problem for most pretreatment methods is the generation of compounds that are inhibitory towards the fermenting microorganisms, primarily phenols. Degradation products that could have inhibitory action in later fermentation steps are avoided during pre-treatment by wet oxidation. Followed by pre treatment, hydrolysed with enzymes known as cellulases and hemicellulases, which hydrolyse cellulose and hemicellulose respectively. The production of bioethanol requires two steps, fermentation and distillation. Practically all ethanol fermentation is still based on Saccharomyces cerevisiae . The fermentation using thermotolerant yeasts has more advantageous in that they have faster fermentation rates, avoid the cooling costs, and decrease the over all fermentation costs, so that ethanol can be made available at cheaper rates. In addition they can be used for efficient simultaneous saccharification and fermentation of cellulose by cellulases because the temperature optimum of cellulase enzymes (about 40 ° C to 45 ° C) is close to the fermentation temperature of thermotolerant yeasts. Hence selection and improvement of thermotolerant yeasts for bioconversion of lignocellulosic substrates is very useful.

  6. Cyberlindnera xylolytica sp. nov., a xylitol-producing yeast species isolated from lignocellulosic materials

    Science.gov (United States)

    Independent surveys of yeasts associated with lignocellulosic-related materials led to the discovery of a novel yeast species belonging to the Cyberlindnera clade (Saccharomycotina, Ascomycota). Analysis of the sequences of the internal transcribed spacer (ITS) region and the D1/D2 domains of the la...

  7. Pichia stipitis xylose reductase helps detoxifying lignocellulosic hydrolysate by reducing 5-hydroxymethyl-furfural (HMF

    Directory of Open Access Journals (Sweden)

    Röder Anja

    2008-06-01

    Full Text Available Abstract Background Pichia stipitis xylose reductase (Ps-XR has been used to design Saccharomyces cerevisiae strains that are able to ferment xylose. One example is the industrial S. cerevisiae xylose-consuming strain TMB3400, which was constructed by expression of P. stipitis xylose reductase and xylitol dehydrogenase and overexpression of endogenous xylulose kinase in the industrial S. cerevisiae strain USM21. Results In this study, we demonstrate that strain TMB3400 not only converts xylose, but also displays higher tolerance to lignocellulosic hydrolysate during anaerobic batch fermentation as well as 3 times higher in vitro HMF and furfural reduction activity than the control strain USM21. Using laboratory strains producing various levels of Ps-XR, we confirm that Ps-XR is able to reduce HMF both in vitro and in vivo. Ps-XR overexpression increases the in vivo HMF conversion rate by approximately 20%, thereby improving yeast tolerance towards HMF. Further purification of Ps-XR shows that HMF is a substrate inhibitor of the enzyme. Conclusion We demonstrate for the first time that xylose reductase is also able to reduce the furaldehyde compounds that are present in undetoxified lignocellulosic hydrolysates. Possible implications of this newly characterized activity of Ps-XR on lignocellulosic hydrolysate fermentation are discussed.

  8. Ethanol fermentation from lignocellulosic hydrolysate by a recombinant xylose- and cellooligosaccharide-assimilating yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Katahira, Satoshi; Fukuda, Hideki [Kobe Univ. (Japan). Div. of Molecular Science; Mizuike, Atsuko; Kondo, Akihiko [Kobe Univ. (Japan). Dept. of Chemical Science and Engineering

    2006-10-15

    The sulfuric acid hydrolysate of lignocellulosic biomass, such as wood chips, from the forest industry is an important material for fuel bioethanol production. In this study, we constructed a recombinant yeast strain that can ferment xylose and cellooligosaccharides by integrating genes for the intercellular expressions of xylose reductase and xylitol dehydrogenase from Pichia stipitis, and xylulokinase from Saccharomyces cerevisiae and a gene for displaying ss-glucosidase from Aspergillus acleatus on the cell surface. In the fermentation of the sulfuric acid hydrolysate of wood chips, xylose and cellooligosaccharides were completely fermented after 36 h by the recombinant strain, and then about 30 g/l ethanol was produced from 73 g/l total sugar added at the beginning. In this case, the ethanol yield of this recombinant yeast was much higher than that of the control yeast. These results demonstrate that the fermentation of the lignocellulose hydrolysate is performed efficiently by the recombinant Saccharomyces strain with abilities for xylose assimilation and cellooligosaccharide degradation. (orig.)

  9. Comparative lipid production by oleaginous yeasts in hydrolyzates of lignocellulosic biomass and process strategy for high titers.

    Science.gov (United States)

    Slininger, Patricia J; Dien, Bruce S; Kurtzman, Cletus P; Moser, Bryan R; Bakota, Erica L; Thompson, Stephanie R; O'Bryan, Patricia J; Cotta, Michael A; Balan, Venkatesh; Jin, Mingjie; Sousa, Leonardo da Costa; Dale, Bruce E

    2016-08-01

    Oleaginous yeasts can convert sugars to lipids with fatty acid profiles similar to those of vegetable oils, making them attractive for production of biodiesel. Lignocellulosic biomass is an attractive source of sugars for yeast lipid production because it is abundant, potentially low cost, and renewable. However, lignocellulosic hydrolyzates are laden with byproducts which inhibit microbial growth and metabolism. With the goal of identifying oleaginous yeast strains able to convert plant biomass to lipids, we screened 32 strains from the ARS Culture Collection, Peoria, IL to identify four robust strains able to produce high lipid concentrations from both acid and base-pretreated biomass. The screening was arranged in two tiers using undetoxified enzyme hydrolyzates of ammonia fiber expansion (AFEX)-pretreated cornstover as the primary screening medium and acid-pretreated switch grass as the secondary screening medium applied to strains passing the primary screen. Hydrolyzates were prepared at ∼18-20% solids loading to provide ∼110 g/L sugars at ∼56:39:5 mass ratio glucose:xylose:arabinose. A two stage process boosting the molar C:N ratio from 60 to well above 400 in undetoxified switchgrass hydrolyzate was optimized with respect to nitrogen source, C:N, and carbon loading. Using this process three strains were able to consume acetic acid and nearly all available sugars to accumulate 50-65% of cell biomass as lipid (w/w), to produce 25-30 g/L lipid at 0.12-0.22 g/L/h and 0.13-0.15 g/g or 39-45% of the theoretical yield at pH 6 and 7, a performance unprecedented in lignocellulosic hydrolyzates. Three of the top strains have not previously been reported for the bioconversion of lignocellulose to lipids. The successful identification and development of top-performing lipid-producing yeast in lignocellulose hydrolyzates is expected to advance the economic feasibility of high quality biodiesel and jet fuels from renewable biomass, expanding the market

  10. Identification of furfural as a key toxin in lignocellulosic hydrolysates and evolution of a tolerant yeast strain

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    Heer, Dominik; Sauer, Uwe

    2008-01-01

    Summary The production of fuel ethanol from low‐cost lignocellulosic biomass currently suffers from several limitations. One of them is the presence of inhibitors in lignocellulosic hydrolysates that are released during pre‐treatment. These compounds inhibit growth and hamper the production of ethanol, thereby affecting process economics. To delineate the effects of such complex mixtures, we conducted a chemical analysis of four different real‐world lignocellulosic hydrolysates and determined their toxicological effect on yeast. By correlating the potential inhibitor abundance to the growth‐inhibiting properties of the corresponding hydrolysates, we identified furfural as an important contributor to hydrolysate toxicity for yeast. Subsequently, we conducted a targeted evolution experiment to improve growth behaviour of the half industrial Saccharomyces cerevisiae strain TMB3400 in the hydrolysates. After about 300 generations, representative clones from these evolved populations exhibited significantly reduced lag phases in medium containing the single inhibitor furfural, but also in hydrolysate‐supplemented medium. Furthermore, these strains were able to grow at concentrations of hydrolysates that effectively killed the parental strain and exhibited significantly improved bioconversion characteristics under industrially relevant conditions. The improved resistance of our evolved strains was based on their capacity to remain viable in a toxic environment during the prolonged, furfural induced lag phase. PMID:21261870

  11. Isolation and characterization of Cupriavidus basilensis HMF14 for biological removal of inhibitors from lignocellulosic hydrolysatembt

    NARCIS (Netherlands)

    Wierckx, N.; Koopman, F.; Bandounas, L.; Winde, J.H.de; Ruijssenaars, H.J.

    2010-01-01

    The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic hydrolysates can be efficiently detoxified biologically with microorganisms that

  12. Integrated approach for selecting efficient Saccharomyces cerevisiae for industrial lignocellulosic fermentations: Importance of yeast chassis linked to process conditions.

    Science.gov (United States)

    Costa, Carlos E; Romaní, Aloia; Cunha, Joana T; Johansson, Björn; Domingues, Lucília

    2017-03-01

    In this work, four robust yeast chassis isolated from industrial environments were engineered with the same xylose metabolic pathway. The recombinant strains were physiologically characterized in synthetic xylose and xylose-glucose medium, on non-detoxified hemicellulosic hydrolysates of fast-growing hardwoods (Eucalyptus and Paulownia) and agricultural residues (corn cob and wheat straw) and on Eucalyptus hydrolysate at different temperatures. Results show that the co-consumption of xylose-glucose was dependent on the yeast background. Moreover, heterogeneous results were obtained among different hydrolysates and temperatures for each individual strain pointing to the importance of designing from the very beginning a tailor-made yeast considering the specific raw material and process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Effect of organic acids on the growth and lipid accumulation of oleaginous yeast Trichosporon fermentans

    Directory of Open Access Journals (Sweden)

    Huang Chao

    2012-01-01

    oleaginous yeast, which is helpful for optimization of biomass hydrolysis processes, detoxified pretreatment of hydrolysates and lipid production using lignocellulosic materials.

  14. Monitoring of Growth and Production Characteristics of Red Yeasts Cultivated on Hydrothermally Pretreated Lignocellulosic Pine Material

    Directory of Open Access Journals (Sweden)

    A. Haronikova

    2018-01-01

    Full Text Available The aim of this work was to compare the production of carotenes and ergosterol by red yeasts grown on pine lignocellulose substrates. The yeast strains Rhodotorula aurantiaca and Sporobolomyces shibatanus were grown on the liquid fraction of steam pretreated pine (210 °C, catalyst SO2. Biomass production on a pine hydrolysate was lower than on glucose. The highest content of carotenoids and ergosterol in the cells of R. aurantiaca grown on pine hydrolysate was about 1.7 mg g–1 and 0.8 mg g–1 (dwt, respectively, and in S. shibatanus about 0.9 mg g–1 and 0.1 mg g–1, respectively. Hemicellulose hydrolysates may contain many compounds that have inhibitory effects on microorganisms. In this work, the influences of some inhibitors were assessed by cultivating yeasts on media with a representative addition of the selected compounds. From these tests, furfural appears to be the most critical inhibitor, whereas acetic acid and 5-hydroxymethyl furfural (HMF do not affect the growth so much.

  15. Enhanced anti-oxidative activity and lignocellulosic ethanol production by biotin addition to medium in Pichia guilliermondii fermentation.

    Science.gov (United States)

    Qi, Kai; Xia, Xiao-Xia; Zhong, Jian-Jiang

    2015-01-01

    Commercialization of lignocellulosic ethanol fermentation requires its high titer, but the reactive oxygen species (ROS) accumulation during the bioprocess damaged the cells and compromised this goal. To improve the cellular anti-oxidative activity during non-detoxified corncob residue hydrolysate fermentation, seed cells were prepared to possess a higher level of intracellular biotin pool (IBP), which facilitated the biosyntheses of catalase and porphyrin. As a result, the catalase activity increased by 1.3-folds compared to control while the ROS level reduced by 50%. Cell viability in high-IBP cells was 1.7-folds of control and the final ethanol titer increased from 31.2 to 41.8 g L(-1) in batch fermentation. The high-IBP cells were further used for repeated-batch fermentation in the non-detoxified lignocellulosic hydrolysate, and the highest titer and average productivity of ethanol reached 63.7 g L(-1) and 1.2 g L(-1)h(-1). The results were favorable to future industrial application of this lignocellulosic bioethanol process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Single-cell Protein and Xylitol Production by a Novel Yeast Strain Candida intermedia FL023 from Lignocellulosic Hydrolysates and Xylose.

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    Wu, Jiaqiang; Hu, Jinlong; Zhao, Shumiao; He, Mingxiong; Hu, Guoquan; Ge, Xiangyang; Peng, Nan

    2018-05-01

    Yeasts are good candidates to utilize the hydrolysates of lignocellulose, the most abundant bioresource, for bioproducts. This study aimed to evaluate the efficiencies of single-cell protein (SCP) and xylitol production by a novel yeast strain, Candida intermedia FL023, from lignocellulosic hydrolysates and xylose. This strain efficiently assimilated hexose, pentose, and cellubiose for cell mass production with the crude protein content of 484.2 g kg -1 dry cell mass. SCP was produced by strain FL023 using corncob hydrolysate and urea as the carbon and nitrogen sources with the dry cell mass productivity 0.86 g L -1  h -1 and the yield of 0.40 g g -1 sugar. SCP was also produced using NaOH-pretreated Miscanthus sinensis straw and corn steep liquor as the carbon and nitrogen sources through simultaneous saccharification and fermentation with the dry cell productivity of 0.23 g L -1  h -1 and yield of 0.17 g g -1 straw. C. intermedia FL023 was tolerant to 0.5 g L -1 furfural, acetic acid, and syringaldehyde in xylitol fermentation and produced 45.7 g L -1 xylitol from xylose with the productivity of 0.38 g L -1  h -1 and the yield of 0.57 g g -1 xylose. This study provides feasible methods for feed and food additive production from the abundant lignocellulosic bioresources.

  17. Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach

    NARCIS (Netherlands)

    Zha, Y.; Westerhuis, J.A.; Muilwijk, B.; Overkamp, K.M.; Nijmeijer, B.M.; Coulier, L.; Smilde, A.K.; Punt, P.J.

    2014-01-01

    Background: Inhibitors are formed that reduce the fermentation performance of fermenting yeast during the pretreatment process of lignocellulosic biomass. An exometabolomics approach was applied to systematically identify inhibitors in lignocellulosic biomass hydrolysates.Results: We studied the

  18. Identifying inhibitory compounds in lignocellulosic biomass hydrolysates using an exometabolomics approach

    NARCIS (Netherlands)

    Zha, Y.; Westerhuis, J.A.; Muilwijk, B.; Overkamp, K.M.; Nijmeijer, B.M.; Coulier, L.; Smilde, A.K.; Punt, P.J.

    2014-01-01

    BACKGROUND: Inhibitors are formed that reduce the fermentation performance of fermenting yeast during the pretreatment process of lignocellulosic biomass. An exometabolomics approach was applied to systematically identify inhibitors in lignocellulosic biomass hydrolysates. RESULTS: We studied the

  19. Novel Biocatalytic Platform for Ethanol Production from Lignocellulosic Feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chyi-Shin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tachea, Firehiwot [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Brown, Sarah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Coffman, Philip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Tanjore, Deepti [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gregg, Allison [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rolison-Welch, Kristina [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shirazi, Fatemeh [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); He, Qian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sun, Ning [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-01-23

    The goals of the CRADA were achieved by illustrating the scalability of immobilized yeast technology, demonstrating lignocellulosic feedstock consumption by the immobilized cells, and confirming Microvi’s proprietary polymer matrix ethanol toxicity tolerance. We conducted fermentations at 2L and 300L scales. For carbon source, we performed pretreatment and saccharification at 100L scale to produce lignocellulosic sugars with glucose and xylose.

  20. Deciphering the Origin, Evolution, and Physiological Function of the Subtelomeric Aryl-Alcohol Dehydrogenase Gene Family in the Yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Yang, Dong-Dong; de Billerbeck, Gustavo M; Zhang, Jin-Jing; Rosenzweig, Frank; Francois, Jean-Marie

    2018-01-01

    Homology searches indicate that Saccharomyces cerevisiae strain BY4741 contains seven redundant genes that encode putative aryl-alcohol dehydrogenases (AAD). Yeast AAD genes are located in subtelomeric regions of different chromosomes, and their functional role(s) remain enigmatic. Here, we show that two of these genes, AAD4 and AAD14 , encode functional enzymes that reduce aliphatic and aryl-aldehydes concomitant with the oxidation of cofactor NADPH, and that Aad4p and Aad14p exhibit different substrate preference patterns. Other yeast AAD genes are undergoing pseudogenization. The 5' sequence of AAD15 has been deleted from the genome. Repair of an AAD3 missense mutation at the catalytically essential Tyr 73 residue did not result in a functional enzyme. However, ancestral-state reconstruction by fusing Aad6 with Aad16 and by N-terminal repair of Aad10 restores NADPH-dependent aryl-alcohol dehydrogenase activities. Phylogenetic analysis indicates that AAD genes are narrowly distributed in wood-saprophyte fungi and in yeast that occupy lignocellulosic niches. Because yeast AAD genes exhibit activity on veratraldehyde, cinnamaldehyde, and vanillin, they could serve to detoxify aryl-aldehydes released during lignin degradation. However, none of these compounds induce yeast AAD gene expression, and Aad activities do not relieve aryl-aldehyde growth inhibition. Our data suggest an ancestral role for AAD genes in lignin degradation that is degenerating as a result of yeast's domestication and use in brewing, baking, and other industrial applications. IMPORTANCE Functional characterization of hypothetical genes remains one of the chief tasks of the postgenomic era. Although the first Saccharomyces cerevisiae genome sequence was published over 20 years ago, 22% of its estimated 6,603 open reading frames (ORFs) remain unverified. One outstanding example of this category of genes is the enigmatic seven-member AAD family. Here, we demonstrate that proteins encoded by two

  1. Aldo-keto reductase enzymes detoxify glyphosate and improve herbicide resistance in plants.

    Science.gov (United States)

    Vemanna, Ramu S; Vennapusa, Amaranatha Reddy; Easwaran, Murugesh; Chandrashekar, Babitha K; Rao, Hanumantha; Ghanti, Kirankumar; Sudhakar, Chinta; Mysore, Kirankumar S; Makarla, Udayakumar

    2017-07-01

    In recent years, concerns about the use of glyphosate-resistant crops have increased because of glyphosate residual levels in plants and development of herbicide-resistant weeds. In spite of identifying glyphosate-detoxifying genes from microorganisms, the plant mechanism to detoxify glyphosate has not been studied. We characterized an aldo-keto reductase gene from Pseudomonas (PsAKR1) and rice (OsAKR1) and showed, by docking studies, both PsAKR1 and OsAKR1 can efficiently bind to glyphosate. Silencing AKR1 homologues in rice and Nicotiana benthamiana or mutation of AKR1 in yeast and Arabidopsis showed increased sensitivity to glyphosate. External application of AKR proteins rescued glyphosate-mediated cucumber seedling growth inhibition. Regeneration of tobacco transgenic lines expressing PsAKR1 or OsAKRI on glyphosate suggests that AKR can be used as selectable marker to develop transgenic crops. PsAKR1- or OsAKRI-expressing tobacco and rice transgenic plants showed improved tolerance to glyphosate with reduced accumulation of shikimic acid without affecting the normal photosynthetic rates. These results suggested that AKR1 when overexpressed detoxifies glyphosate in planta. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  2. Cell recycle batch fermentation of high-solid lignocellulose using a recombinant cellulase-displaying yeast strain for high yield ethanol production in consolidated bioprocessing.

    Science.gov (United States)

    Matano, Yuki; Hasunuma, Tomohisa; Kondo, Akihiko

    2013-05-01

    The aim of this study is to develop a scheme of cell recycle batch fermentation (CRBF) of high-solid lignocellulosic materials. Two-phase separation consisting of rough removal of lignocellulosic residues by low-speed centrifugation and solid-liquid separation enabled effective collection of Saccharomyces cerevisiae cells with decreased lignin and ash. Five consecutive batch fermentation of 200 g/L rice straw hydrothermally pretreated led to an average ethanol titer of 34.5 g/L. Moreover, the display of cellulases on the recombinant yeast cell surface increased ethanol titer to 42.2 g/L. After, five-cycle fermentation, only 3.3 g/L sugar was retained in the fermentation medium, because cellulase displayed on the cell surface hydrolyzed cellulose that was not hydrolyzed by commercial cellulases or free secreted cellulases. Fermentation ability of the recombinant strain was successfully kept during a five-cycle repeated batch fermentation with 86.3% of theoretical yield based on starting biomass. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. The NILE Project - Advances in the Conversion of Lignocellulosic Materials into Ethanol

    International Nuclear Information System (INIS)

    Monot, F.; Margeot, A.; Hahn-Haegerdal, B.; Lindstedt, J.; Slade, R.

    2013-01-01

    NILE ('New Improvements for Lignocellulosic Ethanol') was an integrated European project (2005-2010) devoted to the conversion of lignocellulosic raw materials to ethanol. The main objectives were to design novel enzymes suitable for the hydrolysis of cellulose to glucose and new yeast strains able to efficiently converting all the sugars present in lignocellulose into ethanol. The project also included testing these new developments in an integrated pilot plant and evaluating the environmental and socio-economic impacts of implementing lignocellulosic ethanol on a large scale. Two model raw materials - spruce and wheat straw - both preconditioned with similar pretreatments, were used. Several approaches were explored to improve the saccharification of these pretreated raw materials such as searching for new efficient enzymes and enzyme engineering. Various genetic engineering methods were applied to obtain stable xylose- and arabinose-fermenting Saccharomyces cerevisiae strains that tolerate the toxic compounds present in lignocellulosic hydrolysates. The pilot plant was able to treat 2 tons of dry matter per day, and hydrolysis and fermentation could be run successively or simultaneously. A global model integrating the supply chain was used to assess the performance of lignocellulosic ethanol from an economical and environmental perspective. It was found that directed evolution of a specific enzyme of the cellulolytic cocktail produced by the industrial fungus, Trichoderma reesei, and modification of the composition of this cocktail led to improvements of the enzymatic hydrolysis of pretreated raw material. These results, however, were difficult to reproduce at a large scale. A substantial increase in the ethanol conversion yield and in specific ethanol productivity was obtained through a combination of metabolic engineering of yeast strains and fermentation process development. Pilot trials confirmed the good behaviour of the yeast strains in industrial

  4. Ethanol Production from Lignocellulose by the Dimorphic Fungus Mucor Indicus

    Energy Technology Data Exchange (ETDEWEB)

    Lennartsson, P.R.; Taherzadeh, M.J. (School of Engineering, Univ. of Boraas, SE-50190, Boraas (Sweden)). e-mail: Patrik.Lennartsson@hb.se; Karimi, K. (Dept. of Chemical Engineering, Isfahan Univ. of Technology, 84156-83111, Isfahan (IR)); Edebo, L. (Dept. of Clinical Bacteriology, Univ. of Goeteborg, SE-41346, Goeteborg (Sweden))

    2008-10-15

    Ethanol production from dilute-acid lignocellulosic hydrolyzate by the dimorphic fungus Mucor indicus was investigated. A mixture of different forest wood chips dominated by spruce was hydrolyzed with 0.5 g/L sulfuric acid at 15 bar for 10 min, yielding different sugars including galactose, glucose, mannose, and xylose, but also different fermentation inhibitors such as acetic acid, furfural, hydroxymethyl furfural (HMF), and phenolic compounds. We induced different morphological growth of M. indicus from purely filamentous, mostly filamentous, mostly yeast-like to purely yeast-like. The different forms were then used to ferment the hydrolyzate. They tolerated the presence of the inhibitors under anaerobic batch cultivation well and the ethanol yield was 430-440 g/kg consumed sugars. The ethanol productivity depended on the morphology. Judging from these results, we conclude that M. indicus, is useful for ethanol production from toxic substrates independent of its morphology. Keywords: bio-ethanol, lignocellulosic materials, dilute acid hydrolysis, Mucor indicus, dimorphic fungi

  5. Development of industrial yeast for second generation bioethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Hou, X

    2012-01-15

    The cost of lignocellulose-based bioethanol needs to be reduced, in order to commercialize this clean and sustainable fuel substitute for fossil fuels. A microorganism that can completely and efficiently convert all the sugars in lignocellulose into ethanol is one of the prerequisites of a cost-effective production process. In addition, the microorganisms should also have a high tolerance towards the inhibitory compounds present in the lignocellulosic hydrolysate, which are formed during the pretreatment of lignocellulose. Baker's yeast, Saccharomyces cerevisiae, is generally regarded as a robust microorganism and can efficiently ferment glucose. But it lacks the ability to ferment xylose which comprises 20-35% of lignocellulose. Naturally xylose-fermenting yeast such as Pichia stipitis is much more sensitive to inhibitors than S. cerevisiae and it requires accurately controlled microaerophilic conditions during the xylose fermentation, rendering the process technically difficult and expensive. In this study, a novel xylose fermenting yeast Spathaspora passalidarum displayed fast cell growth and efficient xylose fermentation under anaerobic conditions. In contrast, P. stipitis was almost unable to utilize xylose under the same conditions. It is further demonstrated that S. passalidarum converts xylose by means of NADH-preferred xylose reductase (XR) and NAD+-dependent xylitol dehydrogenase (XDH). Thus, the capacity of S. passalidarum to utilize xylose under anaerobic conditions is possibly due to a balance between supply and demand of cofactor through this XR-XDH pathway. Only one other XR with NADH preference has been reported so far. Unfortunately, S. passalidarum also has a low tolerance towards inhibitors generated during pretreatment, which prevents immediate use of this yeast in industrial application. S. passalidarum is able to convert the inhibitor furfural to furfuryl alcohol in a synthetic medium when the addition of furfural is low. The enzymes involved

  6. Development of industrial yeast for second generation bioethanol production

    Energy Technology Data Exchange (ETDEWEB)

    Hou, X.

    2012-01-15

    The cost of lignocellulose-based bioethanol needs to be reduced, in order to commercialize this clean and sustainable fuel substitute for fossil fuels. A microorganism that can completely and efficiently convert all the sugars in lignocellulose into ethanol is one of the prerequisites of a cost-effective production process. In addition, the microorganisms should also have a high tolerance towards the inhibitory compounds present in the lignocellulosic hydrolysate, which are formed during the pretreatment of lignocellulose. Baker's yeast, Saccharomyces cerevisiae, is generally regarded as a robust microorganism and can efficiently ferment glucose. But it lacks the ability to ferment xylose which comprises 20-35% of lignocellulose. Naturally xylose-fermenting yeast such as Pichia stipitis is much more sensitive to inhibitors than S. cerevisiae and it requires accurately controlled microaerophilic conditions during the xylose fermentation, rendering the process technically difficult and expensive. In this study, a novel xylose fermenting yeast Spathaspora passalidarum displayed fast cell growth and efficient xylose fermentation under anaerobic conditions. In contrast, P. stipitis was almost unable to utilize xylose under the same conditions. It is further demonstrated that S. passalidarum converts xylose by means of NADH-preferred xylose reductase (XR) and NAD+-dependent xylitol dehydrogenase (XDH). Thus, the capacity of S. passalidarum to utilize xylose under anaerobic conditions is possibly due to a balance between supply and demand of cofactor through this XR-XDH pathway. Only one other XR with NADH preference has been reported so far. Unfortunately, S. passalidarum also has a low tolerance towards inhibitors generated during pretreatment, which prevents immediate use of this yeast in industrial application. S. passalidarum is able to convert the inhibitor furfural to furfuryl alcohol in a synthetic medium when the addition of furfural is low. The enzymes

  7. Co-fermentation of glucose, xylose and/or cellobiose by yeast

    Science.gov (United States)

    Jeffries, Thomas W.; Willis, Laura B.; Long, Tanya M.; Su, Yi-Kai

    2013-09-10

    Provided herein are methods of using yeast cells to produce ethanol by contacting a mixture comprising xylose with a Spathaspora yeast cell under conditions suitable to allow the yeast to ferment at least a portion of the xylose to ethanol. The methods allow for efficient ethanol production from hydrolysates derived from lignocellulosic material and sugar mixtures including at least xylose and glucose or xylose, glucose and cellobiose.

  8. Phenotypic characterisation of Saccharomyces spp. yeast for tolerance to stresses encountered during fermentation of lignocellulosic residues to produce bioethanol

    Science.gov (United States)

    2014-01-01

    Background During industrial fermentation of lignocellulose residues to produce bioethanol, microorganisms are exposed to a number of factors that influence productivity. These include inhibitory compounds produced by the pre-treatment processes required to release constituent carbohydrates from biomass feed-stocks and during fermentation, exposure of the organisms to stressful conditions. In addition, for lignocellulosic bioethanol production, conversion of both pentose and hexose sugars is a pre-requisite for fermentative organisms for efficient and complete conversion. All these factors are important to maximise industrial efficiency, productivity and profit margins in order to make second-generation bioethanol an economically viable alternative to fossil fuels for future transport needs. Results The aim of the current study was to assess Saccharomyces yeasts for their capacity to tolerate osmotic, temperature and ethanol stresses and inhibitors that might typically be released during steam explosion of wheat straw. Phenotypic microarray analysis was used to measure tolerance as a function of growth and metabolic activity. Saccharomyces strains analysed in this study displayed natural variation to each stress condition common in bioethanol fermentations. In addition, many strains displayed tolerance to more than one stress, such as inhibitor tolerance combined with fermentation stresses. Conclusions Our results suggest that this study could identify a potential candidate strain or strains for efficient second generation bioethanol production. Knowledge of the Saccharomyces spp. strains grown in these conditions will aid the development of breeding programmes in order to generate more efficient strains for industrial fermentations. PMID:24670111

  9. Yeast strains designed for 2. generation bioethanol production. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Roennow, B.

    2013-04-15

    The aim of the project was to develop a suitable fermentation organism for 2G bioethanol production that would efficiently ferment all of the sugars in lignocellulosic biomass into ethanol at a commercially viable rate (comparable to yeast based 1G ethanol production). More specifically, a yeast strain would be developed with the ability to ferment also the pentoses in lignocellulosic biomass and thereby increase the ethanol yield of the process by 30-45% with a profound positive effect on the total process economy. The project has succeeded in developing a new industrial yeast strain V1. The yeast strain can transform the difficult C5 sugars to ethanol from waste products such as straw and the like from the agricultural sector. The classic issues relating to industrial uses such as inhibitor and ethanol tolerance and high ethanol production is resolved satisfactorily. The potential of the use of the new strain for 2nd generation bioethanol production is that the ethanol yields increase by 30-45%. With the increased ethanol yield follows a marked improvement in the overall process economics. (LN)

  10. Simultaneous Saccharification and Fermentation and Partial Saccharification and Co-Fermentation of Lignocellulosic Biomass for Ethanol Production

    Science.gov (United States)

    Doran-Peterson, Joy; Jangid, Amruta; Brandon, Sarah K.; Decrescenzo-Henriksen, Emily; Dien, Bruce; Ingram, Lonnie O.

    Ethanol production by fermentation of lignocellulosic biomass-derived sugars involves a fairly ancient art and an ever-evolving science. Production of ethanol from lignocellulosic biomass is not avant-garde, and wood ethanol plants have been in existence since at least 1915. Most current ethanol production relies on starch- and sugar-based crops as the substrate; however, limitations of these materials and competing value for human and animal feeds is renewing interest in lignocellulose conversion. Herein, we describe methods for both simultaneous saccharification and fermentation (SSF) and a similar but separate process for partial saccharification and cofermentation (PSCF) of lignocellulosic biomass for ethanol production using yeasts or pentose-fermenting engineered bacteria. These methods are applicable for small-scale preliminary evaluations of ethanol production from a variety of biomass sources.

  11. Yeast metabolic engineering for hemicellulosic ethanol production

    Science.gov (United States)

    Jennifer Van Vleet; Thomas W. Jeffries

    2009-01-01

    Efficient fermentation of hemicellulosic sugars is critical for the bioconversion of lignocellulosics to ethanol. Efficient sugar uptake through the heterologous expression of yeast and fungal xylose/glucose transporters can improve fermentation if other metabolic steps are not rate limiting. Rectification of cofactor imbalances through heterologous expression of...

  12. Simultaneous saccharification and cofermentation of lignocellulosic residues from commercial furfural production and corn kernels using different nutrient media

    Directory of Open Access Journals (Sweden)

    Cristhian Carrasco

    2011-07-01

    Full Text Available Abstract Background As the supply of starch grain and sugar cane, currently the main feedstocks for bioethanol production, become limited, lignocelluloses will be sought as alternative materials for bioethanol production. Production of cellulosic ethanol is still cost-inefficient because of the low final ethanol concentration and the addition of nutrients. We report the use of simultaneous saccharification and cofermentation (SSCF of lignocellulosic residues from commercial furfural production (furfural residue, FR and corn kernels to compare different nutritional media. The final ethanol concentration, yield, number of live yeast cells, and yeast-cell death ratio were investigated to evaluate the effectiveness of integrating cellulosic and starch ethanol. Results Both the ethanol yield and number of live yeast cells increased with increasing corn-kernel concentration, whereas the yeast-cell death ratio decreased in SSCF of FR and corn kernels. An ethanol concentration of 73.1 g/L at 120 h, which corresponded to a 101.1% ethanol yield based on FR cellulose and corn starch, was obtained in SSCF of 7.5% FR and 14.5% corn kernels with mineral-salt medium. SSCF could simultaneously convert cellulose into ethanol from both corn kernels and FR, and SSCF ethanol yield was similar between the organic and mineral-salt media. Conclusions Starch ethanol promotes cellulosic ethanol by providing important nutrients for fermentative organisms, and in turn cellulosic ethanol promotes starch ethanol by providing cellulosic enzymes that convert the cellulosic polysaccharides in starch materials into additional ethanol. It is feasible to produce ethanol in SSCF of FR and corn kernels with mineral-salt medium. It would be cost-efficient to produce ethanol in SSCF of high concentrations of water-insoluble solids of lignocellulosic materials and corn kernels. Compared with prehydrolysis and fed-batch strategy using lignocellulosic materials, addition of starch

  13. Physicochemical Properties of Fungal Detoxified Cassava Mash and ...

    African Journals Online (AJOL)

    The physicochemical properties of fungal detoxified cassava mash and sensory characteristics of wheat-detoxified cassava composite doughnuts were investigated. Fungal isolates from soils collected at cassava processing sites were isolated, quantified and identified. Cassava mash from grated tuber was partially ...

  14. Bioconversion of lignocellulose-derived sugars to ethanol by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Madhavan, Anjali; Srivastava, Aradhana; Kondo, Akihiko; Bisaria, Virendra S

    2012-03-01

    Lignocellulosic biomass from agricultural and agro-industrial residues represents one of the most important renewable resources that can be utilized for the biological production of ethanol. The yeast Saccharomyces cerevisiae is widely used for the commercial production of bioethanol from sucrose or starch-derived glucose. While glucose and other hexose sugars like galactose and mannose can be fermented to ethanol by S. cerevisiae, the major pentose sugars D-xylose and L-arabinose remain unutilized. Nevertheless, D-xylulose, the keto isomer of xylose, can be fermented slowly by the yeast and thus, the incorporation of functional routes for the conversion of xylose and arabinose to xylulose or xylulose-5-phosphate in Saccharomyces cerevisiae can help to improve the ethanol productivity and make the fermentation process more cost-effective. Other crucial bottlenecks in pentose fermentation include low activity of the pentose phosphate pathway enzymes and competitive inhibition of xylose and arabinose transport into the cell cytoplasm by glucose and other hexose sugars. Along with a brief introduction of the pretreatment of lignocellulose and detoxification of the hydrolysate, this review provides an updated overview of (a) the key steps involved in the uptake and metabolism of the hexose sugars: glucose, galactose, and mannose, together with the pentose sugars: xylose and arabinose, (b) various factors that play a major role in the efficient fermentation of pentose sugars along with hexose sugars, and (c) the approaches used to overcome the metabolic constraints in the production of bioethanol from lignocellulose-derived sugars by developing recombinant S. cerevisiae strains.

  15. Fully Integrated Lignocellulosic Biorefinery with Onsite Production of Enzymes and Yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Manoj [DSM Innovation, Incorporated, San Francisco, CA (United States)

    2010-06-14

    Lignocellulosic biomass is the most abundant, least expensive renewable natural biological resource for the production of biobased products and bioenergy is important for the sustainable development of human civilization in 21st century. For making the fermentable sugars from lignocellulosic biomass, a reduction in cellulase production cost, an improvement in cellulase performance, and an increase in sugar yields are all vital to reduce the processing costs of biorefineries. Improvements in specific cellulase activities for non-complexed cellulase mixtures can be implemented through cellulase engineering based on rational design or directed evolution for each cellulase component enzyme, as well as on the reconstitution of cellulase components. In this paper, we will provide DSM's efforts in cellulase research and developments and focus on limitations. Cellulase improvement strategies based on directed evolution using screening on relevant substrates, screening for higher thermal tolerance based on activity screening approaches such as continuous culture using insoluble cellulosic substrates as a powerful selection tool for enriching beneficial cellulase mutants from the large library. We will illustrate why and how thermostable cellulases are vital for economic delivery of bioproducts from cellulosic biomass using biochemical conversion approach.

  16. A short review on SSF – an interesting process option for ethanol production from lignocellulosic feedstocks

    Directory of Open Access Journals (Sweden)

    Bertilsson Magnus

    2008-05-01

    Full Text Available Abstract Simultaneous saccharification and fermentation (SSF is one process option for production of ethanol from lignocellulose. The principal benefits of performing the enzymatic hydrolysis together with the fermentation, instead of in a separate step after the hydrolysis, are the reduced end-product inhibition of the enzymatic hydrolysis, and the reduced investment costs. The principal drawbacks, on the other hand, are the need to find favorable conditions (e.g. temperature and pH for both the enzymatic hydrolysis and the fermentation and the difficulty to recycle the fermenting organism and the enzymes. To satisfy the first requirement, the temperature is normally kept below 37°C, whereas the difficulty to recycle the yeast makes it beneficial to operate with a low yeast concentration and at a high solid loading. In this review, we make a brief overview of recent experimental work and development of SSF using lignocellulosic feedstocks. Significant progress has been made with respect to increasing the substrate loading, decreasing the yeast concentration and co-fermentation of both hexoses and pentoses during SSF. Presently, an SSF process for e.g. wheat straw hydrolyzate can be expected to give final ethanol concentrations close to 40 g L-1 with a yield based on total hexoses and pentoses higher than 70%.

  17. Fermentation of lignocellulosic hydrolysates: Inhibition and detoxification

    Energy Technology Data Exchange (ETDEWEB)

    Palmqvist, E.

    1998-02-01

    The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds produced during hydrolysis. Evaluation of the effect of various biological, physical and chemical detoxification treatments by fermentation assays using Saccharomyces cerevisiae was used to characterise inhibitors. Inhibition of fermentation was decreased after removal of the non-volatile compounds, pre-fermentation by the filamentous fungus Trichoderma reesei, treatment with the lignolytic enzyme laccase, extraction with ether, and treatment with alkali. Yeast growth in lignocellulosic hydrolysates was inhibited below a certain fermentation pH, most likely due to high concentrations of undissociated weak acids. The effect of individual compounds were studied in model fermentations. Furfural is reduced to furfuryl alcohol by yeast dehydrogenases, thereby affecting the intracellular redox balance. As a result, acetaldehyde accumulated during furfural reduction, which most likely contributed to inhibition of growth. Acetic acid (10 g 1{sup -1}) and furfural (3 g 1{sup -1}) interacted antagonistically causing decreased specific growth rate, whereas no significant individual or interaction effects were detected by the lignin-derived compound 4-hydroxybenzoic acid (2 g 1{sup -1}). By maintaining a high cell mass density in the fermentor, the process was less sensitive to inhibitors affecting growth and to fluctuations in fermentation pH, and in addition the depletion rate of bioconvertible inhibitors was increased. A theoretical ethanol yield and high productivity was obtained in continuous fermentation of spruce hydrolysate when the cell mass concentration was maintained at a high level by applying cell recirculation 164 refs, 16 figs, 5 tabs

  18. Cellobiose fermenting yeast produces varied forms of native ß-glucosidase

    Science.gov (United States)

    The rapid growing yeast strain NRRL Y-50464 is robust to environmental stress and resistant to 2-furaldehyde (furfural) and 5-[hydroxymethyl]-2-furaldehyde (HMF). It is able to utilize cellobiose as its sole source of carbon and produces ethanol from lignocellulosic biomass by simultaneous saccharif...

  19. Laccase enzyme detoxifies hydrolysates and improves biogas production from hemp straw and miscanthus.

    Science.gov (United States)

    Schroyen, Michel; Van Hulle, Stijn W H; Holemans, Sander; Vervaeren, Han; Raes, Katleen

    2017-11-01

    The impact of various phenolic compounds, vanillic acid, ferulic acid, p-coumaric acid and 4-hydroxybenzoic acid on anaerobic digestion of lignocellulosic biomass (hemp straw and miscanthus) was studied. Such phenolic compounds have been known to inhibit biogas production during anaerobic digestion. The different phenolic compounds were added in various concentrations: 0, 100, 500, 1000 and 2000mg/L. A difference in inhibition of biomethane production between the phenolic compounds was noted. Hydrolysis rate, during anaerobic digestion of miscanthus was inhibited up to 50% by vanillic acid, while vanillic acid had no influence on the initial rate of biogas production during the anaerobic digestion of hemp straw. Miscanthus has a higher lignin concentration (12-30g/100gDM) making it less accessible for degradation, and in combination with phenolic compounds released after harsh pretreatments, it can cause severe inhibition levels during the anaerobic digestion, lowering biogas production. To counter the inhibition, lignin degrading enzymes can be used to remove or degrade the inhibitory phenolic compounds. The interaction of laccase and versatile peroxidase individually with the different phenolic compounds was studied to have insight in the polymerization of inhibitory compounds or breakdown of lignocellulose. Hemp straw and miscanthus were incubated with 0, 100 and 500mg/L of the different phenolic compounds for 0, 6 and 24h and pretreated with the lignin degrading enzymes. A laccase pretreatment successfully detoxified the substrate, while versatile peroxidase however was inhibited by 100mg/L of each of the individual phenolic compounds. Finally a combination of enzymatic detoxification and subsequent biogas production showed that a decrease in phenolic compounds by laccase treatment can considerably lower the inhibition levels of the biogas production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass

    DEFF Research Database (Denmark)

    Klinke, H.B.; Thomsen, A.B.; Ahring, Birgitte Kiær

    2004-01-01

    for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation-depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar......An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible...... degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q...

  1. Biodetoxification of toxins generated from lignocellulose pretreatment using a newly isolated fungus, Amorphotheca resinae ZN1, and the consequent ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Wang Wei

    2010-11-01

    Full Text Available Abstract Background Degradation of the toxic compounds generated in the harsh pretreatment of lignocellulose is an inevitable step in reducing the toxin level for conducting practical enzymatic hydrolysis and ethanol fermentation processes. Various detoxification methods have been tried and many negative outcomes were found using these methods, such as the massive freshwater usage and wastewater generation, loss of the fine lignocellulose particles and fermentative sugars and incomplete removal of inhibitors. An alternate method, biodetoxification, which degrades the toxins as part of their normal metabolism, was considered a promising option for the removal of toxins without causing the above problems. Results A kerosene fungus strain, Amorphotheca resinae ZN1, was isolated from the microbial community growing on the pretreated corn stover material. The degradation of the toxins as well as the lignocelluloses-derived sugars was characterized in different ways, and the results show that A. resinae ZN1 utilized each of these toxins and sugars as the sole carbon sources efficiently and grew quickly on the toxins. It was found that the solid-state culture of A. resinae ZN1 on various pretreated lignocellulose feedstocks such as corn stover, wheat straw, rice straw, cotton stalk and rape straw degraded all kinds of toxins quickly and efficiently. The consequent simultaneous saccharification and ethanol fermentation was performed at the 30% (wt/wt solid loading of the detoxified lignocellulosic feedstocks without a sterilization step, and the ethanol titer in the fermentation broth reached above 40 g/L using food crop residues as feedstocks. Conclusions The advantages of the present biodetoxification by A. resinae ZN1 over the known detoxification methods include zero energy input, zero wastewater generation, complete toxin degradation, processing on solid pretreated material, no need for sterilization and a wide lignocellulose feedstock spectrum

  2. Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source.

    Science.gov (United States)

    Cassa-Barbosa, L A; Procópio, R E L; Matos, I T S R; Filho, S A

    2015-09-28

    Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

  3. Method for pretreating lignocellulosic biomass

    Science.gov (United States)

    Kuzhiyil, Najeeb M.; Brown, Robert C.; Dalluge, Dustin Lee

    2015-08-18

    The present invention relates to a method for pretreating lignocellulosic biomass containing alkali and/or alkaline earth metal (AAEM). The method comprises providing a lignocellulosic biomass containing AAEM; determining the amount of the AAEM present in the lignocellulosic biomass; identifying, based on said determining, the amount of a mineral acid sufficient to completely convert the AAEM in the lignocellulosic biomass to thermally-stable, catalytically-inert salts; and treating the lignocellulosic biomass with the identified amount of the mineral acid, wherein the treated lignocellulosic biomass contains thermally-stable, catalytically inert AAEM salts.

  4. Yeasts in sustainable bioethanol production: A review.

    Science.gov (United States)

    Mohd Azhar, Siti Hajar; Abdulla, Rahmath; Jambo, Siti Azmah; Marbawi, Hartinie; Gansau, Jualang Azlan; Mohd Faik, Ainol Azifa; Rodrigues, Kenneth Francis

    2017-07-01

    Bioethanol has been identified as the mostly used biofuel worldwide since it significantly contributes to the reduction of crude oil consumption and environmental pollution. It can be produced from various types of feedstocks such as sucrose, starch, lignocellulosic and algal biomass through fermentation process by microorganisms. Compared to other types of microoganisms, yeasts especially Saccharomyces cerevisiae is the common microbes employed in ethanol production due to its high ethanol productivity, high ethanol tolerance and ability of fermenting wide range of sugars. However, there are some challenges in yeast fermentation which inhibit ethanol production such as high temperature, high ethanol concentration and the ability to ferment pentose sugars. Various types of yeast strains have been used in fermentation for ethanol production including hybrid, recombinant and wild-type yeasts. Yeasts can directly ferment simple sugars into ethanol while other type of feedstocks must be converted to fermentable sugars before it can be fermented to ethanol. The common processes involves in ethanol production are pretreatment, hydrolysis and fermentation. Production of bioethanol during fermentation depends on several factors such as temperature, sugar concentration, pH, fermentation time, agitation rate, and inoculum size. The efficiency and productivity of ethanol can be enhanced by immobilizing the yeast cells. This review highlights the different types of yeast strains, fermentation process, factors affecting bioethanol production and immobilization of yeasts for better bioethanol production.

  5. Yeasts in sustainable bioethanol production: A review

    Directory of Open Access Journals (Sweden)

    Siti Hajar Mohd Azhar

    2017-07-01

    Full Text Available Bioethanol has been identified as the mostly used biofuel worldwide since it significantly contributes to the reduction of crude oil consumption and environmental pollution. It can be produced from various types of feedstocks such as sucrose, starch, lignocellulosic and algal biomass through fermentation process by microorganisms. Compared to other types of microoganisms, yeasts especially Saccharomyces cerevisiae is the common microbes employed in ethanol production due to its high ethanol productivity, high ethanol tolerance and ability of fermenting wide range of sugars. However, there are some challenges in yeast fermentation which inhibit ethanol production such as high temperature, high ethanol concentration and the ability to ferment pentose sugars. Various types of yeast strains have been used in fermentation for ethanol production including hybrid, recombinant and wild-type yeasts. Yeasts can directly ferment simple sugars into ethanol while other type of feedstocks must be converted to fermentable sugars before it can be fermented to ethanol. The common processes involves in ethanol production are pretreatment, hydrolysis and fermentation. Production of bioethanol during fermentation depends on several factors such as temperature, sugar concentration, pH, fermentation time, agitation rate, and inoculum size. The efficiency and productivity of ethanol can be enhanced by immobilizing the yeast cells. This review highlights the different types of yeast strains, fermentation process, factors affecting bioethanol production and immobilization of yeasts for better bioethanol production.

  6. State of the art review of biofuels production from lignocellulose by thermophilic bacteria.

    Science.gov (United States)

    Jiang, Yujia; Xin, Fengxue; Lu, Jiasheng; Dong, Weiliang; Zhang, Wenming; Zhang, Min; Wu, Hao; Ma, Jiangfeng; Jiang, Min

    2017-12-01

    Biofuels, including ethanol and butanol, are mainly produced by mesophilic solventogenic yeasts and Clostridium species. However, these microorganisms cannot directly utilize lignocellulosic materials, which are abundant, renewable and non-compete with human demand. More recently, thermophilic bacteria show great potential for biofuels production, which could efficiently degrade lignocellulose through the cost effective consolidated bioprocessing. Especially, it could avoid contamination in the whole process owing to its relatively high fermentation temperature. However, wild types thermophiles generally produce low levels of biofuels, hindering their large scale production. This review comprehensively summarizes the state of the art development of biofuels production by reported thermophilic microorganisms, and also concludes strategies to improve biofuels production including the metabolic pathways construction, co-culturing systems and biofuels tolerance. In addition, strategies to further improve butanol production are proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Yeast Biomass Production in Brewery's Spent Grains Hemicellulosic Hydrolyzate

    Science.gov (United States)

    Duarte, Luís C.; Carvalheiro, Florbela; Lopes, Sónia; Neves, Ines; Gírio, Francisco M.

    Yeast single-cell protein and yeast extract, in particular, are two products which have many feed, food, pharmaceutical, and biotechnological applications. However, many of these applications are limited by their market price. Specifically, the yeast extract requirements for culture media are one of the major technical hurdles to be overcome for the development of low-cost fermentation routes for several top value chemicals in a biorefinery framework. A potential biotechnical solution is the production of yeast biomass from the hemicellulosic fraction stream. The growth of three pentose-assimilating yeast cell factories, Debaryomyces hansenii, Kluyveromyces marxianus, and Pichia stipitis was compared using non-detoxified brewery's spent grains hemicellulosic hydrolyzate supplemented with mineral nutrients. The yeasts exhibited different specific growth rates, biomass productivities, and yields being D. hansenii as the yeast species that presented the best performance, assimilating all sugars and noteworthy consuming most of the hydrolyzate inhibitors. Under optimized conditions, D. hansenii displayed a maximum specific growth rate, biomass yield, and productivity of 0.34 h-1, 0.61 g g-1, and 0.56 g 1-1 h-1, respectively. The nutritional profile of D. hansenii was thoroughly evaluated, and it compares favorably to others reported in literature. It contains considerable amounts of some essential amino acids and a high ratio of unsaturated over saturated fatty acids.

  8. Mechanisms of yeast stress tolerance and its manipulation for efficient fuel ethanol production.

    Science.gov (United States)

    Zhao, X Q; Bai, F W

    2009-10-12

    Yeast strains of Saccharomyces cerevisiae have been extensively studied in recent years for fuel ethanol production, in which yeast cells are exposed to various stresses such as high temperature, ethanol inhibition, and osmotic pressure from product and substrate sugars as well as the inhibitory substances released from the pretreatment of lignocellulosic biomass. An in-depth understanding of the mechanism of yeast stress tolerance contributes to breeding more robust strains for ethanol production, especially under very high gravity conditions. Taking advantage of the "omics" technology, the stress response and defense mechanism of yeast cells during ethanol fermentation were further explored, and the newly emerged tools such as genome shuffling and global transcription machinery engineering have been applied to breed stress resistant yeast strains for ethanol production. In this review, the latest development of stress tolerance mechanisms was focused, and improvement of yeast stress tolerance by both random and rational tools was presented.

  9. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411

    Science.gov (United States)

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47–0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2–2.7 g/L/h and a total sugar conversion of 90–99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

  10. Fungal Enzymes and Yeasts for Conversion of Plant Biomass to Bioenergy and High-Value Products

    DEFF Research Database (Denmark)

    Lange, Lene

    2017-01-01

    Fungi and fungal enzymes play important roles in the new bioeconomy. Enzymes from filamentous fungi can unlock the potential of recalcitrant lignocellulose structures of plant cell walls as a new resource, and fungi such as yeast can produce bioethanol from the sugars released after enzyme treatm...... contributed to mycology and environmental research? Future perspectives and approaches are listed, highlighting the importance of fungi in development of the bioeconomy.......Fungi and fungal enzymes play important roles in the new bioeconomy. Enzymes from filamentous fungi can unlock the potential of recalcitrant lignocellulose structures of plant cell walls as a new resource, and fungi such as yeast can produce bioethanol from the sugars released after enzyme...... treatment. Such processes reflect inherent characteristics of the fungal way of life, namely, that fungi as heterotrophic organisms must break down complex carbon structures of organic materials to satisfy their need for carbon and nitrogen for growth and reproduction. This chapter describes major steps...

  11. Engineering and two-stage evolution of a lignocellulosic hydrolysate-tolerant Saccharomyces cerevisiae strain for anaerobic fermentation of xylose from AFEX pretreated corn stover.

    Directory of Open Access Journals (Sweden)

    Lucas S Parreiras

    Full Text Available The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX-pretreated corn stover hydrolysate (ACSH. We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH.

  12. Radioprotective properties of detoxified lipid A

    International Nuclear Information System (INIS)

    Snyder, S.L.; Walden, T.L. Jr.; Patchen, M.L.

    1985-01-01

    Endotoxic lipopolysaccharide (LPS) has long been known to possess radioprotective properties. Nevertheless, the toxicity of LPS, or its principal bioactive component, Lipid A, has detracted from its potential use as a radioprotectant. Recently, a relatively non-toxic monophosphoryl Lipid A that retains many of the immunobiological properties of native LPS has been prepared from a polyaccharide-deficient and heptoseless Re mutant strain of S. minnesota. The authors conducted experiments that evaluated and compared the radioprotective efficiency of native endotoxin, as well as the mono (detoxified) and diphosphoryl (toxic) forms of Lipid A, in both responder (CD2F1 and C3H/HeN) and non-responder (C3H/HeJ) mice. It has been found that the optimal dose for the mono- and diphosphoryl Lipid A are approximately the same (800 μg/kg in CD2F1 mice), and that both compounds provide maximum protection when administered 24 h before exposure to an LD100 dose of cobalt - 60 gamma radiation. Possible mechanisms for the radioprotective action of detoxified Lipid A are suggested

  13. Melatonin: a protective and detoxifying agent in paraquat toxicity

    International Nuclear Information System (INIS)

    Ghanem, M.; Gad, H.; Hanan; Aziz, A.; Nasr, M.

    2002-01-01

    The ability of melatonin as a protective and detoxifying agent against paraquat-induced oxidative damage in rat lungs and liver was examined. Changes in reduced glutathione (OSH) concentration and malonaldehyde (MDA) level were measured. Pathological examination to lungs and liver was done. Paraquat in 2 doses (20,70 mg/kg) was injected I.P. into rats with melatonin (10 mg/kg) I. P. either before and after paraquat intoxication or only after it. Melatonin proved its protective role when given before and after paraquat intoxication more than its detoxifying effect when given only after paraquat. The biochemical improvement following melatonin therapy was more evident than the histopathological one. (author)

  14. Improved inhibitor tolerance in xylose-fermenting yeast Spathaspora passalidarum by mutagenesis and protoplast fusion

    DEFF Research Database (Denmark)

    Hou, Xiaoru; Yao, Shuo

    2012-01-01

    The xylose-fermenting yeast Spathaspora passalidarum showed excellent fermentation performance utilizing glucose and xylose under anaerobic conditions. But this yeast is highly sensitive to the inhibitors such as furfural present in the pretreated lignocellulosic biomass. In order to improve...... from fusion of the protoplasts of S. passalidarum M7 and a robust yeast, Saccharomyces cerevisiae ATCC 96581, were able to grow in 75% WSLQ and produce around 0.4 g ethanol/g consumed xylose. Among the selected hybrid strains, the hybrid FS22 showed the best fermentation capacity in 75% WSLQ...... the inhibitor tolerance of this yeast, a combination of UV mutagenesis and protoplast fusion was used to construct strains with improved performance. Firstly, UVinduced mutants were screened and selected for improved tolerance towards furfural. The most promised mutant, S. passalidarum M7, produced 50% more...

  15. Signature gene expressions of cell wall integrity pathway concur with tolerance response of industrial yeast Saccharomyces cerevisiae against biomass pretreatment inhibitors

    Science.gov (United States)

    Traditional industrial ethanologenic yeast Saccharomyces cerevisiae has a robust performance under various environmental conditions and can be served as a candidate for the next-generation biocatalyst development for advanced biofuels production using lignocellulose mateials. Overcoming toxic compou...

  16. Cellulolytic enzyme expression and simultaneous conversion of lignocellulosic sugars into ethanol and xylitol by a new Candida tropicalis strain.

    Science.gov (United States)

    Mattam, Anu Jose; Kuila, Arindam; Suralikerimath, Niranjan; Choudary, Nettem; Rao, Peddy V C; Velankar, Harshad Ravindra

    2016-01-01

    Lignocellulosic ethanol production involves major steps such as thermochemical pretreatment of biomass, enzymatic hydrolysis of pre-treated biomass and the fermentation of released sugars into ethanol. At least two different organisms are conventionally utilized for producing cellulolytic enzymes and for ethanol production through fermentation, whereas in the present study a single yeast isolate with the capacity to simultaneously produce cellulases and xylanases and ferment the released sugars into ethanol and xylitol has been described. A yeast strain isolated from soil samples and identified as Candida tropicalis MTCC 25057 expressed cellulases and xylanases over a wide range of temperatures (32 and 42 °C) and in the presence of different cellulosic substrates [carboxymethylcellulose and wheat straw (WS)]. The studies indicated that the cultivation of yeast at 42 °C in pre-treated hydrolysate containing 0.5 % WS resulted in proportional expression of cellulases (exoglucanases and endoglucanases) at concentrations of 114.1 and 97.8 U g(-1) ds, respectively. A high xylanase activity (689.3 U g(-1) ds) was also exhibited by the yeast under similar growth conditions. Maximum expression of cellulolytic enzymes by the yeast occurred within 24 h of incubation. Of the sugars released from biomass after pretreatment, 49 g L(-1) xylose was aerobically converted into 15.8 g L(-1) of xylitol. In addition, 25.4 g L(-1) glucose released after the enzymatic hydrolysis of biomass was fermented by the same yeast to obtain an ethanol titer of 7.3 g L(-1). During the present study, a new strain of C. tropicalis was isolated and found to have potential for consolidated bioprocessing (CBP) applications. The strain could grow in a wide range of process conditions (temperature, pH) and in the presence of lignocellulosic inhibitors such as furfural, HMF and acetic acid. The new yeast produced cellulolytic enzymes over a wide temperature range and in the presence of

  17. Ethanol production from lignocellulosic materials. Fermentation and on-line analysis

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, L.

    1994-04-01

    The fermentation performance of bacteria, yeast and fungi was investigated in lignocellulosic hydrolysates with the aim of finding microorganisms which both withstand the inhibitors and that have the ability to ferment pentoses. Firstly, the performance of Saccharomyces cidri, Saccharomyces cerevisiae, Lactobacillus brevis, Lactococcus lactis ssp lactis, Escherichia coli and Zymomonas mobilis was investigated in spent sulphite liquor and enzymatic hydrolysate of steam-pretreated willow. Secondly, the performance of natural and recombinant E. coli, Pichia stipitis, recombinant S. cerevisiae, S. cerevisiae in combination with xylose isomerase and Fusarium oxysporum was investigated in a xylose-rich acid hydrolysate of corn cob. Recombinant E. coli was the best alternative for fermentation of lignocellulosic hydrolysates, giving both high yields and productivities. The main drawback was that detoxification was necessary. The kinetics of the fermentation with recombinant E. coli KO11 was investigated in the condensate of steam-pretreated willow. A cost analysis of the ethanol production from willow was made, which predicted an ethanol production cost of 3.9 SEK/l for the pentose fermentation. The detoxification cost constituted 22% of this cost. The monitoring of three monosaccharides and ethanol in lignocellulosic hydro lysates is described. The monosaccharides were determined using immobilized pyranose oxidase in an on-line amperometric analyser. Immobilization and characterization of pyranose oxidase from Phanerochaete chrysosporium is also described. The ethanol was monitored on-line using a micro dialysis probe as an in situ sampling device. The dialysate components were then separated in a column liquid chromatographic system and the ethanol was selectively detected by an amperometric alcohol bio sensor. The determinations with on-line analysis methods agreed well with off-line methods. 248 refs, 4 figs, 12 tabs

  18. Fermentative performance of bacteria and yeasts in lignocellulose hydrolysates

    Energy Technology Data Exchange (ETDEWEB)

    Olsson, Lisbeth; Hahn-Haegerdal, B. (Lund Univ. (Sweden). Dept. of Applied Microbiology)

    1993-01-01

    The sugar consumption rates and the product formation of yeasts (Saccharomyces cidri NCYC 775, S. cerevisiae NCYC 1047, S.cerevisiae ATCC 4132) and bacteria (Lactobacillus brevis DSM 20054, Lactococcus lactis ssp. lactis ATCC 19435, Escherichia coli ATCC 11303, Zymomonas mobilis ATCC 31821) were investigated in spent sulphite liquor and an enzymatic hydrolysate of steam-pretreated Salix caprea at different pH values in order to elucidate the suitability of the organisms with respect to future genetic engineering approaches. The possible inhibitory action of the two substrates on the investigated microorganisms was also considered. S.cerevisiae emerged as one of the better candidates, owing to its fast sugar consumption rate and efficient ethanol production. (author)

  19. Phenotypic evaluation and characterization of 21 industrial Saccharomyces cerevisiae yeast strains.

    Science.gov (United States)

    Kong, In Iok; Turner, Timothy Lee; Kim, Heejin; Kim, Soo Rin; Jin, Yong-Su

    2018-02-01

    Microorganisms have been studied and used extensively to produce value-added fuels and chemicals. Yeasts, specifically Saccharomyces cerevisiae, receive industrial attention because of their well-known ability to ferment glucose and produce ethanol. Thousands of natural or genetically modified S. cerevisiae have been found in industrial environments for various purposes. These industrial strains are isolated from industrial fermentation sites, and they are considered as potential host strains for superior fermentation processes. In many cases, industrial yeast strains have higher thermotolerance, increased resistances towards fermentation inhibitors and increased glucose fermentation rates under anaerobic conditions when compared with laboratory yeast strains. Despite the advantages of industrial strains, they are often not well characterized. Through screening and phenotypic characterization of commercially available industrial yeast strains, industrial fermentation processes requiring specific environmental conditions may be able to select an ideal starting yeast strain to be further engineered. Here, we have characterized and compared 21 industrial S. cerevisiae strains under multiple conditions, including their tolerance to varying pH conditions, resistance to fermentation inhibitors, sporulation efficiency and ability to ferment lignocellulosic sugars. These data may be useful for the selection of a parental strain for specific biotechnological applications of engineered yeast. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. A Weibull statistics-based lignocellulose saccharification model and a built-in parameter accurately predict lignocellulose hydrolysis performance.

    Science.gov (United States)

    Wang, Mingyu; Han, Lijuan; Liu, Shasha; Zhao, Xuebing; Yang, Jinghua; Loh, Soh Kheang; Sun, Xiaomin; Zhang, Chenxi; Fang, Xu

    2015-09-01

    Renewable energy from lignocellulosic biomass has been deemed an alternative to depleting fossil fuels. In order to improve this technology, we aim to develop robust mathematical models for the enzymatic lignocellulose degradation process. By analyzing 96 groups of previously published and newly obtained lignocellulose saccharification results and fitting them to Weibull distribution, we discovered Weibull statistics can accurately predict lignocellulose saccharification data, regardless of the type of substrates, enzymes and saccharification conditions. A mathematical model for enzymatic lignocellulose degradation was subsequently constructed based on Weibull statistics. Further analysis of the mathematical structure of the model and experimental saccharification data showed the significance of the two parameters in this model. In particular, the λ value, defined the characteristic time, represents the overall performance of the saccharification system. This suggestion was further supported by statistical analysis of experimental saccharification data and analysis of the glucose production levels when λ and n values change. In conclusion, the constructed Weibull statistics-based model can accurately predict lignocellulose hydrolysis behavior and we can use the λ parameter to assess the overall performance of enzymatic lignocellulose degradation. Advantages and potential applications of the model and the λ value in saccharification performance assessment were discussed. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Complex effect of lignocellulosic biomass pretreatment with 1-butyl-3-methylimidazolium chloride ionic liquid on various aspects of ethanol and fumaric acid production by immobilized cells within SSF.

    Science.gov (United States)

    Dotsenko, Anna S; Dotsenko, Gleb S; Senko, Olga V; Stepanov, Nikolay A; Lyagin, Ilya V; Efremenko, Elena N; Gusakov, Alexander V; Zorov, Ivan N; Rubtsova, Ekaterina A

    2018-02-01

    The pretreatment of softwood and hardwood samples (spruce and hornbeam wood) with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was undertaken for further simultaneous enzymatic saccharification of renewable non-food lignocellulosic biomass and microbial fermentation of obtained sugars to ethanol and fumaric acid. A multienzyme cocktail based on cellulases and yeast or fungus cells producing ethanol and fumaric acid were the main objects of [Bmim]Cl influence studies. A complex effect of lignocellulosic biomass pretreatment with [Bmim]Cl on various aspects of the process (both action of cellulases and microbial conversion of hydrolysates to target products) was revealed. Positive effects of the pretreatment with [Bmim]Cl included decreasing the lignin content in the biomass, and increasing the effectiveness of enzymatic hydrolysis and microbial transformation of pretreated biomass. Immobilized cells of both yeasts and fungi possessed improved productive characteristics in the biotransformation of biomass pretreated with [Bmim]Cl to ethanol and fumaric acid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. The Effectiveness of Transactional Behavior Analytic Group Therapy on the Prevention of Relapse among Detoxified People

    OpenAIRE

    S Mousa Kafi; Rahim Mollazadeh Esfanaji; Morteza Nori; Ertaj Salehi

    2009-01-01

    Introduction: Addiction Phenomenon among detoxified people is an important therapeutic problem for substance abusers. The aim of this research was the study of effectiveness of transactional behavior analytic group therapy on prevention of relapse of detoxified people. Method: the research design was quasi experimental with witness group. By using of available sampling of detoxified people who referred to government centers for maintenance therapy with Methadone, 24 subjects that divided to t...

  3. Biotechnological production of ethanol from renewable resources by Neurospora crassa: an alternative to conventional yeast fermentations?

    Science.gov (United States)

    Dogaris, Ioannis; Mamma, Diomi; Kekos, Dimitris

    2013-02-01

    Microbial production of ethanol might be a potential route to replace oil and chemical feedstocks. Bioethanol is by far the most common biofuel in use worldwide. Lignocellulosic biomass is the most promising renewable resource for fuel bioethanol production. Bioconversion of lignocellulosics to ethanol consists of four major unit operations: pretreatment, hydrolysis, fermentation, and product separation/distillation. Conventional bioethanol processes for lignocellulosics apply commercial fungal cellulase enzymes for biomass hydrolysis, followed by yeast fermentation of resulting glucose to ethanol. The fungus Neurospora crassa has been used extensively for genetic, biochemical, and molecular studies as a model organism. However, the strain's potential in biotechnological applications has not been widely investigated and discussed. The fungus N. crassa has the ability to synthesize and secrete all three enzyme types involved in cellulose hydrolysis as well as various enzymes for hemicellulose degradation. In addition, N. crassa has been reported to convert to ethanol hexose and pentose sugars, cellulose polymers, and agro-industrial residues. The combination of these characteristics makes N. crassa a promising alternative candidate for biotechnological production of ethanol from renewable resources. This review consists of an overview of the ethanol process from lignocellulosic biomass, followed by cellulases and hemicellulases production, ethanol fermentations of sugars and lignocellulosics, and industrial application potential of N. crassa.

  4. Expression of enzymes in yeast for lignocellulose derived oligomer CBP

    Science.gov (United States)

    McBride, John E.; Wiswall, Erin; Shikhare, Indraneel; Xu, Haowen; Thorngren, Naomi; Hau, Heidi H.; Stonehouse, Emily

    2017-08-29

    The present invention provides a multi-component enzyme system that hydrolyzes hemicellulose oligomers from hardwood which can be expressed, for example, in yeast such as Saccharomyces cerevisiae. In some embodiments, this invention provides for the engineering of a series of biocatalysts combining the expression and secretion of components of this enzymatic system with robust, rapid xylose utilization, and ethanol fermentation under industrially relevant process conditions for consolidated bioprocessing. In some embodiments, the invention utilizes co-cultures of strains that can achieve significantly improved performance due to the incorporation of additional enzymes in the fermentation system.

  5. YKL071W from Saccharomyces cerevisiae encodes a novel aldehyde reductase for detoxification of glycolaldehyde and furfural derived from lignocellulose.

    Science.gov (United States)

    Wang, Hanyu; Ouyang, Yidan; Zhou, Chang; Xiao, Difan; Guo, Yaping; Wu, Lan; Li, Xi; Gu, Yunfu; Xiang, Quanju; Zhao, Ke; Yu, Xiumei; Zou, Likou; Ma, Menggen

    2017-12-01

    Aldehydes generated as by-products during the pretreatment of lignocellulose are the key inhibitors to Saccharomyces cerevisiae, which is considered as the most promising microorganism for industrial production of biofuel, xylitol as well as other special chemicals from lignocellulose. S. cerevisiae has the inherent ability to in situ detoxify aldehydes to corresponding alcohols by multiple aldehyde reductases. Herein, we report that an uncharacterized open reading frame YKL071W from S. cerevisiae encodes a novel "classical" short-chain dehydrogenase/reductase (SDR) protein with NADH-dependent enzymatic activities for reduction of furfural (FF), glycolaldehyde (GA), formaldehyde (FA), and benzaldehyde (BZA). This enzyme showed much better specific activities for reduction of GA and FF than FA and BZA, and displayed much higher Km and Kcat/Km but lower Vmax and Kcat for reduction of GA than FF. For this enzyme, the optimum pH was 5.5 and 6.0 for reduction of GA and FF, and the optimum temperature was 30 °C for reduction of GA and FF. Both pH and temperature affected stability of this enzyme in a similar trend for reduction of GA and FF. Cu 2+ , Zn 2+ , Ni 2+ , and Fe 3+ had severe inhibition effects on enzyme activities of Ykl071wp for reduction of GA and FF. Transcription of YKL071W in S. cerevisiae was significantly upregulated under GA and FF stress conditions, and its transcription is most probably regulated by transcription factor genes of YAP1, CAD1, PDR3, and STB5. This research provides guidelines to identify more uncharacterized genes with reductase activities for detoxification of aldehydes derived from lignocellulose in S. cerevisiae.

  6. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    International Nuclear Information System (INIS)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    1987-01-01

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells. (author)

  7. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    Science.gov (United States)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

  8. Apparent digestibility of nutrients, energy, and amino acid of nontoxic and detoxified physic nut cakes for Nile tilapia

    Directory of Open Access Journals (Sweden)

    Hamilton Hisano

    2015-09-01

    Full Text Available Abstract:The objective of this work was to evaluate the apparent digestibility coefficients of nutrients, energy, and amino acids of nontoxic and detoxified physic nut cakes treated with solvent plus posterior extrusion, for Nile tilapia. The apparent digestibility coefficients of crude protein and gross energy were higher for detoxified than for nontoxic physic nut cake. However, the apparent digestibility coefficient of ether extract of the nontoxic physic nut cake was higher than that of the detoxified one. The apparent digestibility coefficient of amino acids of both feed ingredients was superior to 80%, except for glycine, for the nontoxic psychic nut cake, and for threonine, for the detoxified one. Nontoxic and detoxified physic nut cakes show apparent digestibility coefficient values equivalent to those of the other evaluated oilseeds and potential for inclusion in Nile tilapia diets.

  9. Model-based plant-wide optimization of large-scale lignocellulosic bioethanol plants

    DEFF Research Database (Denmark)

    Prunescu, Remus Mihail; Blanke, Mogens; Jakobsen, Jon Geest

    2017-01-01

    Second generation biorefineries transform lignocellulosic biomass into chemicals with higher added value following a conversion mechanism that consists of: pretreatment, enzymatic hydrolysis, fermentation and purification. The objective of this study is to identify the optimal operational point...... with respect to maximum economic profit of a large scale biorefinery plant using a systematic model-based plantwide optimization methodology. The following key process parameters are identified as decision variables: pretreatment temperature, enzyme dosage in enzymatic hydrolysis, and yeast loading per batch...... in fermentation. The plant is treated in an integrated manner taking into account the interactions and trade-offs between the conversion steps. A sensitivity and uncertainty analysis follows at the optimal solution considering both model and feed parameters. It is found that the optimal point is more sensitive...

  10. Developing symbiotic consortia for lignocellulosic biofuel production

    Energy Technology Data Exchange (ETDEWEB)

    Zuroff, Trevor R.; Curtis, Wayne R. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering

    2012-02-15

    The search for petroleum alternatives has motivated intense research into biological breakdown of lignocellulose to produce liquid fuels such as ethanol. Degradation of lignocellulose for biofuel production is a difficult process which is limited by, among other factors, the recalcitrance of lignocellulose and biological toxicity of the products. Consolidated bioprocessing has been suggested as an efficient and economical method of producing low value products from lignocellulose; however, it is not clear whether this would be accomplished more efficiently with a single organism or community of organisms. This review highlights examples of mixtures of microbes in the context of conceptual models for developing symbiotic consortia for biofuel production from lignocellulose. Engineering a symbiosis within consortia is a putative means of improving both process efficiency and stability relative to monoculture. Because microbes often interact and exist attached to surfaces, quorum sensing and biofilm formation are also discussed in terms of consortia development and stability. An engineered, symbiotic culture of multiple organisms may be a means of assembling a novel combination of metabolic capabilities that can efficiently produce biofuel from lignocellulose. (orig.)

  11. Can lignocellulosic hydrocarbon liquids rival lignocellulose-derived ethanol as a future transport fuel?

    Directory of Open Access Journals (Sweden)

    Yao Ding

    2012-11-01

    Full Text Available Although transport fuels are currently obtained mainly from petroleum, alternative fuels derived from lignocellulosic biomass (LB have drawn much attention in recent years in light of the limited reserves of crude oil and the associated environmental issues. Lignocellulosic ethanol (LE and lignocellulosic hydrocarbons (LH are two typical representatives of the LB-derived transport fuels. This editorial systematically compares LE and LB from production to their application in transport fuels. It can be demonstrated that LH has many advantages over LE relative to such uses. However, most recent studies on the production of the LB-derived transport fuels have focused on LE production. Hence, it is strongly recommended that more research should be aimed at developing an efficient and economically viable process for industrial LH production.

  12. Efficacy and safety testing of mycotoxin-detoxifying agents in broilers following the European Food Safety Authority guidelines.

    Science.gov (United States)

    Osselaere, A; Devreese, M; Watteyn, A; Vandenbroucke, V; Goossens, J; Hautekiet, V; Eeckhout, M; De Saeger, S; De Baere, S; De Backer, P; Croubels, S

    2012-08-01

    Contamination of feeds with mycotoxins is a worldwide problem and mycotoxin-detoxifying agents are used to decrease their negative effect. The European Food Safety Authority recently stated guidelines and end-points for the efficacy testing of detoxifiers. Our study revealed that plasma concentrations of deoxynivalenol and deepoxy-deoxynivalenol were too low to assess efficacy of 2 commercially available mycotoxin-detoxifying agents against deoxynivalenol after 3 wk of continuous feeding of this mycotoxin at concentrations of 2.44±0.70 mg/kg of feed and 7.54±2.20 mg/kg of feed in broilers. This correlates with the poor absorption of deoxynivalenol in poultry. A safety study with 2 commercially available detoxifying agents and veterinary drugs showed innovative results with regard to the pharmacokinetics of 2 antibiotics after oral dosing in the drinking water. The plasma and kidney tissue concentrations of oxytetracycline were significantly higher in broilers receiving a biotransforming agent in the feed compared with control birds. For amoxicillin, the plasma concentrations were significantly higher for broilers receiving an adsorbing agent in comparison to birds receiving the biotransforming agent, but not to the control group. Mycotoxin-detoxifying agents can thus interact with the oral bioavailability of antibiotics depending on the antibiotic and detoxifying agent, with possible adverse effects on the health of animals and humans.

  13. Co-Utilization of Glucose and Xylose for Enhanced Lignocellulosic Ethanol Production with Reverse Membrane Bioreactors

    Directory of Open Access Journals (Sweden)

    Mofoluwake M. Ishola

    2015-12-01

    Full Text Available Integrated permeate channel (IPC flat sheet membranes were examined for use as a reverse membrane bioreactor (rMBR for lignocellulosic ethanol production. The fermenting organism, Saccharomyces cerevisiae (T0936, a genetically-modified strain with the ability to ferment xylose, was used inside the rMBR. The rMBR was evaluated for simultaneous glucose and xylose utilization as well as in situ detoxification of furfural and hydroxylmethyl furfural (HMF. The synthetic medium was investigated, after which the pretreated wheat straw was used as a xylose-rich lignocellulosic substrate. The IPC membrane panels were successfully used as the rMBR during the batch fermentations, which lasted for up to eight days without fouling. With the rMBR, complete glucose and xylose utilization, resulting in 86% of the theoretical ethanol yield, was observed with the synthetic medium. Its application with the pretreated wheat straw resulted in complete glucose consumption and 87% xylose utilization; a final ethanol concentration of 30.3 g/L was obtained, which corresponds to 83% of the theoretical yield. Moreover, complete in situ detoxification of furfural and HMF was obtained within 36 h and 60 h, respectively, with the rMBR. The use of the rMBR is a promising technology for large-scale lignocellulosic ethanol production, since it facilitates the co-utilization of glucose and xylose; moreover, the technology would also allow the reuse of the yeast for several batches.

  14. Co-Utilization of Glucose and Xylose for Enhanced Lignocellulosic Ethanol Production with Reverse Membrane Bioreactors

    Science.gov (United States)

    Ishola, Mofoluwake M.; Ylitervo, Päivi; Taherzadeh, Mohammad J.

    2015-01-01

    Integrated permeate channel (IPC) flat sheet membranes were examined for use as a reverse membrane bioreactor (rMBR) for lignocellulosic ethanol production. The fermenting organism, Saccharomyces cerevisiae (T0936), a genetically-modified strain with the ability to ferment xylose, was used inside the rMBR. The rMBR was evaluated for simultaneous glucose and xylose utilization as well as in situ detoxification of furfural and hydroxylmethyl furfural (HMF). The synthetic medium was investigated, after which the pretreated wheat straw was used as a xylose-rich lignocellulosic substrate. The IPC membrane panels were successfully used as the rMBR during the batch fermentations, which lasted for up to eight days without fouling. With the rMBR, complete glucose and xylose utilization, resulting in 86% of the theoretical ethanol yield, was observed with the synthetic medium. Its application with the pretreated wheat straw resulted in complete glucose consumption and 87% xylose utilization; a final ethanol concentration of 30.3 g/L was obtained, which corresponds to 83% of the theoretical yield. Moreover, complete in situ detoxification of furfural and HMF was obtained within 36 h and 60 h, respectively, with the rMBR. The use of the rMBR is a promising technology for large-scale lignocellulosic ethanol production, since it facilitates the co-utilization of glucose and xylose; moreover, the technology would also allow the reuse of the yeast for several batches. PMID:26633530

  15. Detoxifying of high strength textile effluent through chemical and bio-oxidation processes.

    Science.gov (United States)

    Manekar, Pravin; Patkar, Guarav; Aswale, Pawan; Mahure, Manisha; Nandy, Tapas

    2014-04-01

    Small-scale textile industries (SSTIs) in India struggled for the economic and environmental race. A full-scale common treatment plant (CETP) working on the principle of destabilising negative charge colloidal particles and bio-oxidation of dissolved organic failed to comply with Inland Surface Waters (ISW) standards. Thus, presence of intense colour and organics with elevated temperature inhibited the process stability. Bench scale treatability studies were conducted on chemical and biological processes for its full-scale apps to detoxify a high strength textile process effluent. Colour, SS and COD removals from the optimised chemical process were 88%, 70% and 40%, respectively. Heterotrophic bacteria oxidised COD and BOD more than 84% and 90% at a loading rate 0.0108kgm(-3)d(-1) at 3h HRT. The combined chemical and bio-oxidation processes showed a great promise for detoxifying the toxic process effluent, and implemented in full-scale CETP. The post-assessment of the CETP resulted in detoxify the toxic effluent. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Use of a two-chamber reactor to improve enzymatic hydrolysis and fermentation of lignocellulosic materials

    International Nuclear Information System (INIS)

    Viola, E.; Zimbardi, F.; Valerio, V.; Nanna, F.; Battafarano, A.

    2013-01-01

    Highlights: ► A two-chamber reactor is proposed to improve bioethanol production. ► Hydrolysis and fermentation can be made simultaneous at different temperatures. ► The residue of lignin can be easily separated at the end of the process. -- Abstract: A special type of bioreactor was designed and tested in order to improve the bioethanol production from lignocellulosic materials via enzymatic hydrolysis and fermentation. The reactor consists of two chambers kept at different temperatures and separated by a porous medium, through which the solutes can diffuse. The reactor was tested using as substrate wheat straw previously steam exploded and detoxified. The yields of cellulose hydrolysis and glucose fermentation obtained using this reactor were compared to those obtained by simultaneous enzymatic hydrolysis and fermentation (SSF) carried out in only one vessel. The results showed that a significant increase in the ethanol yield (20%) can be achieved by using this bioreactor. An additional advantage of the reactor is the confinement of the solid lignin in one chamber, allowing a simplified separation process between broth and unreacted residue.

  17. Biomimetic acellular detoxified glutaraldehyde cross-linked bovine pericardium for tissue engineering

    International Nuclear Information System (INIS)

    Mathapati, Santosh; Bishi, Dillip Kumar; Guhathakurta, Soma; Cherian, Kotturathu Mammen; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Verma, Rama Shanker

    2013-01-01

    Glutaraldehyde (GLUT) processing, cellular antigens, calcium ions in circulation, and phospholipids present in the native tissue are predominantly responsible for calcification, degeneration, and lack of natural microenvironment for host progenitor cell migration in tissue implants. The study presents an improved methodology for adhesion and proliferation of endothelial progenitor cells (EPCs) without significant changes in biomechanical and biodegradation properties of the processed acellular bovine pericardium. The anti-calcification potential of the processed tissue was enhanced by detoxification of GLUT-cross-linked bovine pericardium by decellularization, pretreating it with ethanol or removing the free aldehydes by citric acid treatment and lyophilization. The treated tissues were assessed for biomechanical properties, GLUT ligand quantification, adhesion, proliferation of EPCs, and biodegradability. The results indicate that there was no significant change in biomechanical properties and biodegradability when enzymatic hydrolysis (p > 0.05) is employed in detoxified acellular GLUT cross-linked tissue (DBP–G–CA–ET), compared with the native detoxified GLUT cross-linked bovine pericardium (NBP–G–CA–ET). DBP–G–CA–ET exhibited a significant (p > 0.05) increase in the viability of EPCs and cell adhesion as compared to acellular GLUT cross-linked bovine pericardium (p < 0.05). Lyophilized acellular detoxified GLUT cross-linked bovine pericardium, employed in our study as an alternative to conventional GLUT cross-linked bovine pericardium, might provide longer durability and better biocompatibility, and reduce calcification. The developed bovine pericardium patches could be used in cardiac reconstruction and repair, arteriotomy, soft tissue repair, and general surgical procedures with tissue regeneration dimensions. - Highlights: ► We improved the quality of patch biomaterial for cardiovascular surgical procedures. ► Bovine pericardium was

  18. Biomimetic acellular detoxified glutaraldehyde cross-linked bovine pericardium for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Mathapati, Santosh; Bishi, Dillip Kumar [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai (India); Frontier Lifeline Pvt Ltd. and Dr. K. M. Cherian Heart Foundation, Mogappair, Chennai (India); Healthcare and Energy Materials Laboratory, NUSNNI, Faculty of Engineering, National University of Singapore (Singapore); Guhathakurta, Soma [Departmet of Engineering Design, Indian Institute of Technology Madras, Chennai (India); Cherian, Kotturathu Mammen [Frontier Lifeline Pvt Ltd. and Dr. K. M. Cherian Heart Foundation, Mogappair, Chennai (India); Venugopal, Jayarama Reddy; Ramakrishna, Seeram [Healthcare and Energy Materials Laboratory, NUSNNI, Faculty of Engineering, National University of Singapore (Singapore); Verma, Rama Shanker, E-mail: vermars@iitm.ac.in [Stem Cell and Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai (India)

    2013-04-01

    Glutaraldehyde (GLUT) processing, cellular antigens, calcium ions in circulation, and phospholipids present in the native tissue are predominantly responsible for calcification, degeneration, and lack of natural microenvironment for host progenitor cell migration in tissue implants. The study presents an improved methodology for adhesion and proliferation of endothelial progenitor cells (EPCs) without significant changes in biomechanical and biodegradation properties of the processed acellular bovine pericardium. The anti-calcification potential of the processed tissue was enhanced by detoxification of GLUT-cross-linked bovine pericardium by decellularization, pretreating it with ethanol or removing the free aldehydes by citric acid treatment and lyophilization. The treated tissues were assessed for biomechanical properties, GLUT ligand quantification, adhesion, proliferation of EPCs, and biodegradability. The results indicate that there was no significant change in biomechanical properties and biodegradability when enzymatic hydrolysis (p > 0.05) is employed in detoxified acellular GLUT cross-linked tissue (DBP–G–CA–ET), compared with the native detoxified GLUT cross-linked bovine pericardium (NBP–G–CA–ET). DBP–G–CA–ET exhibited a significant (p > 0.05) increase in the viability of EPCs and cell adhesion as compared to acellular GLUT cross-linked bovine pericardium (p < 0.05). Lyophilized acellular detoxified GLUT cross-linked bovine pericardium, employed in our study as an alternative to conventional GLUT cross-linked bovine pericardium, might provide longer durability and better biocompatibility, and reduce calcification. The developed bovine pericardium patches could be used in cardiac reconstruction and repair, arteriotomy, soft tissue repair, and general surgical procedures with tissue regeneration dimensions. - Highlights: ► We improved the quality of patch biomaterial for cardiovascular surgical procedures. ► Bovine pericardium was

  19. Acetylation of woody lignocellulose: significance and regulation

    Directory of Open Access Journals (Sweden)

    Prashant Mohan-Anupama Pawar

    2013-05-01

    Full Text Available Non-cellulosic cell wall polysaccharides constitute approximately one quarter of usable biomass for human exploitation. In contrast to cellulose, these components are usually substituted by O-acetyl groups, which affect their properties and interactions with other polymers, thus affecting their solubility and extractability. However, details of these interactions are still largely obscure. Moreover, polysaccharide hydrolysis to constituent monosaccharides, is hampered by the presence of O-acetyl groups, necessitating either enzymatic (esterase or chemical de-acetylation, increasing the costs and chemical consumption. Reduction of polysaccharide acetyl content in planta is a way to modify lignocellulose towards improved saccharification. In this review we: 1 summarize literature on lignocellulose acetylation in different tree species, 2 present data and current hypotheses concerning the role of O-acetylation in determining woody lignocellulose properties, 3 describe plant proteins involved in lignocellulose O-acetylation, 4 give examples of microbial enzymes capable to de-acetylate lignocellulose, and 5 discuss prospects for exploiting these enzymes in planta to modify xylan acetylation.

  20. Synthetic Biology and Metabolic Engineering Approaches and Its Impact on Non-Conventional Yeast and Biofuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Madhavan, Aravind [Biotechnology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Trivandrum (India); Rajiv Gandhi Centre for Biotechnology, Trivandrum (India); Jose, Anju Alphonsa; Binod, Parameswaran; Sindhu, Raveendran, E-mail: sindhurgcb@gmail.com; Sukumaran, Rajeev K. [Biotechnology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Trivandrum (India); Pandey, Ashok [Biotechnology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Trivandrum (India); Center for Innovative and Applied Bioprocessing, Mohali, Punjab (India); Castro, Galliano Eulogio [Dpt. Ingeniería Química, Ambiental y de los Materiales Edificio, Universidad de Jaén, Jaén (Spain)

    2017-04-25

    The increasing fossil fuel scarcity has led to an urgent need to develop alternative fuels. Currently microorganisms have been extensively used for the production of first-generation biofuels from lignocellulosic biomass. Yeast is the efficient producer of bioethanol among all existing biofuels option. Tools of synthetic biology have revolutionized the field of microbial cell factories especially in the case of ethanol and fatty acid production. Most of the synthetic biology tools have been developed for the industrial workhorse Saccharomyces cerevisiae. The non-conventional yeast systems have several beneficial traits like ethanol tolerance, thermotolerance, inhibitor tolerance, genetic diversity, etc., and synthetic biology have the power to expand these traits. Currently, synthetic biology is slowly widening to the non-conventional yeasts like Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. Herein, we review the basic synthetic biology tools that can apply to non-conventional yeasts. Furthermore, we discuss the recent advances employed to develop efficient biofuel-producing non-conventional yeast strains by metabolic engineering and synthetic biology with recent examples. Looking forward, future synthetic engineering tools’ development and application should focus on unexplored non-conventional yeast species.

  1. Synthetic Biology and Metabolic Engineering Approaches and Its Impact on Non-Conventional Yeast and Biofuel Production

    Directory of Open Access Journals (Sweden)

    Raveendran Sindhu

    2017-04-01

    Full Text Available The increasing fossil fuel scarcity has led to an urgent need to develop alternative fuels. Currently microorganisms have been extensively used for the production of first-generation biofuels from lignocellulosic biomass. Yeast is the efficient producer of bioethanol among all existing biofuels option. Tools of synthetic biology have revolutionized the field of microbial cell factories especially in the case of ethanol and fatty acid production. Most of the synthetic biology tools have been developed for the industrial workhorse Saccharomyces cerevisiae. The non-conventional yeast systems have several beneficial traits like ethanol tolerance, thermotolerance, inhibitor tolerance, genetic diversity, etc., and synthetic biology have the power to expand these traits. Currently, synthetic biology is slowly widening to the non-conventional yeasts like Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. Herein, we review the basic synthetic biology tools that can apply to non-conventional yeasts. Furthermore, we discuss the recent advances employed to develop efficient biofuel-producing non-conventional yeast strains by metabolic engineering and synthetic biology with recent examples. Looking forward, future synthetic engineering tools’ development and application should focus on unexplored non-conventional yeast species.

  2. Synthetic Biology and Metabolic Engineering Approaches and Its Impact on Non-Conventional Yeast and Biofuel Production

    International Nuclear Information System (INIS)

    Madhavan, Aravind; Jose, Anju Alphonsa; Binod, Parameswaran; Sindhu, Raveendran; Sukumaran, Rajeev K.; Pandey, Ashok; Castro, Galliano Eulogio

    2017-01-01

    The increasing fossil fuel scarcity has led to an urgent need to develop alternative fuels. Currently microorganisms have been extensively used for the production of first-generation biofuels from lignocellulosic biomass. Yeast is the efficient producer of bioethanol among all existing biofuels option. Tools of synthetic biology have revolutionized the field of microbial cell factories especially in the case of ethanol and fatty acid production. Most of the synthetic biology tools have been developed for the industrial workhorse Saccharomyces cerevisiae. The non-conventional yeast systems have several beneficial traits like ethanol tolerance, thermotolerance, inhibitor tolerance, genetic diversity, etc., and synthetic biology have the power to expand these traits. Currently, synthetic biology is slowly widening to the non-conventional yeasts like Hansenula polymorpha, Kluyveromyces lactis, Pichia pastoris, and Yarrowia lipolytica. Herein, we review the basic synthetic biology tools that can apply to non-conventional yeasts. Furthermore, we discuss the recent advances employed to develop efficient biofuel-producing non-conventional yeast strains by metabolic engineering and synthetic biology with recent examples. Looking forward, future synthetic engineering tools’ development and application should focus on unexplored non-conventional yeast species.

  3. Effect of radio-detoxified endotoxin on the liver microsomal drug metabolizing enzyme system in rats

    International Nuclear Information System (INIS)

    Bertok, L.; Szeberenyi, S.

    1983-01-01

    E. coli endotoxin (LPS) depresses the hepatic microsomal mono-oxygenase activity. Radio-detoxified LPS (TOLERIN: 60 Co irradiated endotoxin preparation) decreases this biotransforming activity to a smaller extent. Phenobarbital, an inducer of this mono-oxygenase system, failed to induce in LPS-treated animals. In radio-detoxified LPS-treated rats, phenobarbital induced the mono-oxygenase and almost fully restored the biotransformation

  4. Engineering sugar utilization and microbial tolerance toward lignocellulose conversion

    Directory of Open Access Journals (Sweden)

    Lizbeth M. Nieves

    2015-02-01

    Full Text Available Production of fuels and chemicals through a fermentation-based manufacturing process that uses renewable feedstock such as lignocellulosic biomass is a desirable alternative to petrochemicals. Although it is still in its infancy, synthetic biology offers great potential to overcome the challenges associated with lignocellulose conversion. In this review, we will summarize the identification and optimization of synthetic biological parts used to enhance the utilization of lignocellulose-derived sugars and to increase the biocatalyst tolerance for lignocellulose-derived fermentation inhibitors. We will also discuss the ongoing efforts and future applications of synthetic integrated biological systems used to improve lignocellulose conversion.

  5. Effects of some inhibitors on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides and preparation of biodiesel by enzymatic transesterification of the lipid.

    Science.gov (United States)

    Zhao, Xuebing; Peng, Feng; Du, Wei; Liu, Canming; Liu, Dehua

    2012-08-01

    Microbial lipid produced using yeast fermentation with inexpensive carbon sources such as lignocellulosic hydrolyzate can be an alternative feedstock for biodiesel production. Several inhibitors that can be generated during acid hydrolysis of lignocellulose were added solely or together into the culture medium to study their individual inhibitory actions and their synergistic effects on the growth and lipid accumulation of oleaginous yeast Rhodosporidium toruloides. When the inhibitors were present in isolation in the medium, to obtain a high cell biomass accumulation, the concentrations of formic acid, acetic acid, furfural and vanillin should be lower than 2, 5, 0.5 and 1.5 g/L, respectively. However, the synergistic effects of these compounds could dramatically decrease the minimum critical inhibitory concentrations leading to significant growth and lipid production inhibitions. Unlike the above-cited inhibitors, sodium lignosulphonate had no negative influence on biomass accumulation when its concentration was in the range of 0.5-2.0 g/L; in effect, it was found to facilitate cell growth and sugar-to-lipid conversion. The fatty acid compositional profile of the yeast lipid was in the compositional range of various plant oils and animal tallow. Finally, the crude yeast lipid from bagasse hydrolyzate could be well converted into fatty acid methyl ester (FAME, biodiesel) by enzymatic transesterification in a tert-butanol system with biodiesel yield of 67.2% and lipid-to-biodiesel conversion of 88.4%.

  6. Understanding the tolerance of the industrial yeast Saccharomyces cerevisiae against a major class of toxic aldehyde compounds.

    Science.gov (United States)

    Liu, ZongLin Lewis

    2018-07-01

    Development of the next-generation biocatalyst is vital for fermentation-based industrial applications and a sustainable bio-based economy. Overcoming the major class of toxic compounds associated with lignocellulose-to-biofuels conversion is one of the significant challenges for new strain development. A significant number of investigations have been made to understand mechanisms of the tolerance for industrial yeast. It is humbling to learn how complicated the cell's response to the toxic chemicals is and how little we have known about yeast tolerance in the universe of the living cell. This study updates our current knowledge on the tolerance of industrial yeast against aldehyde inhibitory compounds at cellular, molecular and the genomic levels. It is comprehensive yet specific based on reproducible evidence and cross confirmed findings from different investigations using varied experimental approaches. This research approaches a rational foundation toward a more comprehensive understanding on the yeast tolerance. Discussions and perspectives are also proposed for continued exploring the puzzle of the yeast tolerance to aid the next-generation biocatalyst development.

  7. Lignocellulosic sugar management for xylitol and ethanol fermentation with multiple cell recycling by Kluyveromyces marxianus IIPE453.

    Science.gov (United States)

    Dasgupta, Diptarka; Ghosh, Debashish; Bandhu, Sheetal; Adhikari, Dilip K

    2017-07-01

    Optimum utilization of fermentable sugars from lignocellulosic biomass to deliver multiple products under biorefinery concept has been reported in this work. Alcohol fermentation has been carried out with multiple cell recycling of Kluyveromyces marxianus IIPE453. The yeast utilized xylose-rich fraction from acid and steam treated biomass for cell generation and xylitol production with an average yield of 0.315±0.01g/g while the entire glucose rich saccharified fraction had been fermented to ethanol with high productivity of 0.9±0.08g/L/h. A detailed insight into its genome illustrated the strain's complete set of genes associated with sugar transport and metabolism for high-temperature fermentation. A set flocculation proteins were identified that aided in high cell recovery in successive fermentation cycles to achieve alcohols with high productivity. We have brought biomass derived sugars, yeast cell biomass generation, and ethanol and xylitol fermentation in one platform and validated the overall material balance. 2kg sugarcane bagasse yielded 193.4g yeast cell, and with multiple times cell recycling generated 125.56g xylitol and 289.2g ethanol (366mL). Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    OpenAIRE

    Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

    2011-01-01

    Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

  9. 2G ethanol from the whole sugarcane lignocellulosic biomass

    OpenAIRE

    Pereira, Sandra Cerqueira; Maehara, Larissa; Machado, Cristina Maria Monteiro; Farinas, Cristiane Sanchez

    2015-01-01

    Background In the sugarcane industry, large amounts of lignocellulosic residues are generated, which includes bagasse, straw, and tops. The use of the whole sugarcane lignocellulosic biomass for the production of second-generation (2G) ethanol can be a potential alternative to contribute to the economic viability of this process. Here, we conducted a systematic comparative study of the use of the lignocellulosic residues from the whole sugarcane lignocellulosic biomass (bagasse, straw, and to...

  10. Bioethanol production from residual lignocellulosic materials: A review – Part 2

    Directory of Open Access Journals (Sweden)

    CRISTIAN-TEODOR BURUIANA

    2013-08-01

    Full Text Available Lignocellulosic material (LCM can be employed as feedstock for biorefineries, a concept related to industries designed to process biomass for producing chemicals, fuels and/or electrical power. According to this philosophy, LCM can be fractionated and the resulting fractions employed for specific applications. Bioethanol production from cellulosic fraction of LCM involves: hydrolysis of polysaccharides and fermentation of the monomers into bioethanol. Enzymatic hydrolysis is catalyzed by cellulolytic enzymes and fermentation is carried out by bacteria, yeasts or fungi. The main objective of this article is to review different process integration technologies for bioethanol production from LCM. This paper include: separate hydrolysis and fermentation (SHF, simultaneous saccharification and fermentation (SSF, and simultaneous saccharification and co-fermentation (SSCF methods. Furthermore, the fermentation process and a comparative data of cellulases, hemicellulases and ethanol producing-microorganisms were presented.

  11. Efficient chemical and enzymatic saccharification of the lignocellulosic residue from Agave tequilana bagasse to produce ethanol by Pichia caribbica.

    Science.gov (United States)

    Saucedo-Luna, Jaime; Castro-Montoya, Agustin Jaime; Martinez-Pacheco, Mauro Manuel; Sosa-Aguirre, Carlos Ruben; Campos-Garcia, Jesus

    2011-06-01

    Bagasse of Agave tequilana (BAT) is the residual lignocellulosic waste that remains from tequila production. In this study we characterized the chemical composition of BAT, which was further saccharified and fermented to produce ethanol. BAT was constituted by cellulose (42%), hemicellulose (20%), lignin (15%), and other (23%). Saccharification of BAT was carried out at 147 °C with 2% sulfuric acid for 15 min, yielding 25.8 g/l of fermentable sugars, corresponding to 36.1% of saccharificable material (cellulose and hemicellulose contents, w/w). The remaining lignocellulosic material was further hydrolyzed by commercial enzymes, ~8.2% of BAT load was incubated for 72 h at 40 °C rendering 41 g/l of fermentable sugars corresponding to 73.6% of the saccharificable material (w/w). Mathematic surface response analysis of the acid and enzymatic BAT hydrolysis was used for process optimization. The results showed a satisfactory correlation (R (2) = 0.90) between the obtained and predicted responses. The native yeast Pichia caribbica UM-5 was used to ferment sugar liquors from both acid and enzymatic hydrolysis to ethanol yielding 50 and 87%, respectively. The final optimized process generated 8.99 g ethanol/50 g of BAT, corresponding to an overall 56.75% of theoretical ethanol (w/w). Thus, BAT may be employed as a lignocellulosic raw material for bioethanol production and can contribute to BAT residue elimination from environment.

  12. A survey of yeast from the Yarrowia clade for lipid production in dilute-acid pretreated lignocellulosic biomass hydrolysate

    Science.gov (United States)

    Yarrowia lipolytica is an oleaginous yeast species that has attracted attention as a model organism for synthesis of single cell oil. Among over 50 isolates of Y. lipolytica identified, only a few of the strains have been studied extensively. Furthermore, 12 other yeast species were recently assigne...

  13. The Effectiveness of Transactional Behavior Analytic Group Therapy on the Prevention of Relapse among Detoxified People

    Directory of Open Access Journals (Sweden)

    S Mousa Kafi

    2009-08-01

    Full Text Available Introduction: Addiction Phenomenon among detoxified people is an important therapeutic problem for substance abusers. The aim of this research was the study of effectiveness of transactional behavior analytic group therapy on prevention of relapse of detoxified people. Method: the research design was quasi experimental with witness group. By using of available sampling of detoxified people who referred to government centers for maintenance therapy with Methadone, 24 subjects that divided to two control and witness groups (12 subjects for each group selected of Bojnord city. Each subjects completed the write's relapse prediction scale as pretest. Post test administered after group therapy and after 5 months follow up test administered among two groups. Morphine test has done with follow up test simultaneously. Independent samples t-test and covariance analysis has run for analyzing of data. Results: The results of covariance showed that tempting of substance use was significantly differed in post test and follow up, but there was not significant difference in probability of substance use. Conclusion: Finding of this research showed, the transactional behavior analytic group therapy may be effective in tempting of substance use among detoxified people and it can considered by specialists.

  14. Enzymatic conversion of lignocellulose into fermentable sugars

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Kristensen, Jan Bach; Felby, Claus

    2007-01-01

    and hemicelluloses but these are not readily accessible to enzymatic hydrolysis and require a pretreatment, which causes an extensive modification of the lignocellulosic structure. A number of pretreatment technologies are under development and being tested in pilot scale. Hydrolysis of lignocellulose carbohydrates...

  15. Lignocellulose biotechnology: issues of bioconversion and enzyme ...

    African Journals Online (AJOL)

    Lignocellulose biotechnology: issues of bioconversion and enzyme production. ... and secondly to highlight some of the modern approaches which potentially could be used to tackle one of the major impediments, namely high enzyme cost, to speed-up the extensive commercialisation of the lignocellulose bioprocessing.

  16. Oleaginous yeasts: Promising platforms for the production of oleochemicals and biofuels.

    Science.gov (United States)

    Adrio, José L

    2017-09-01

    Oleaginous yeasts have a unique physiology that makes them the best suited hosts for the production of lipids, oleochemicals, and diesel-like fuels. Their high lipogenesis, capability of growing on many different carbon sources (including lignocellulosic sugars), easy large-scale cultivation, and an increasing number of genetic tools are some of the advantages that have encouraged their use to develop sustainable processes. This mini-review summarizes the metabolic engineering strategies developed in oleaginous yeasts within the last 2 years to improve process metrics (titer, yield, and productivity) for the production of lipids, free fatty acids, fatty acid-based chemicals (e.g., fatty alcohols, fatty acid ethyl esters), and alkanes. During this short period of time, tremendous progress has been made in Yarrowia lipolytica, the model oleaginous yeast, which has been engineered to improve lipid production by different strategies including increasing lipogenic pathway flux and biosynthetic precursors, and blocking degradation pathways. Moreover, remarkable advances have also been reported in Rhodosporidium toruloides and Lipomyces starkey despite the limited genetic tools available for these two very promising hosts. Biotechnol. Bioeng. 2017;114: 1915-1920. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  17. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    Directory of Open Access Journals (Sweden)

    Sanchi Nenkova

    2011-04-01

    Full Text Available Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of copper sulfides in the lignocellulosic matrix were investigated. The modification with a system of 2 components: cupric sulfate pentahydrate (CuSO4. 5H2O and sodium thiosulfate pentahydrate (Na2S2O3.5H2O for wood fibers is preferred. Optimal parameters were established for the process: 40 % of the reduction system; hydromodule M=1:6; and ratio of cupric sulfate pentahydrate:sodium thiosulfate pentahydrate = 1:2. The coordinative connection of copper ions with oxygen atoms of cellulose OH groups and aromatic nucleus in lignin macromolecule was observed.

  18. Cellulase Production from Spent Lignocellulose Hydrolysates by Recombinant Aspergillus niger▿

    Science.gov (United States)

    Alriksson, Björn; Rose, Shaunita H.; van Zyl, Willem H.; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

    2009-01-01

    A recombinant Aspergillus niger strain expressing the Hypocrea jecorina endoglucanase Cel7B was grown on spent hydrolysates (stillage) from sugarcane bagasse and spruce wood. The spent hydrolysates served as excellent growth media for the Cel7B-producing strain, A. niger D15[egI], which displayed higher endoglucanase activities in the spent hydrolysates than in standard medium with a comparable monosaccharide content (e.g., 2,100 nkat/ml in spent bagasse hydrolysate compared to 480 nkat/ml in standard glucose-based medium). In addition, A. niger D15[egI] was also able to consume or convert other lignocellulose-derived compounds, such as acetic acid, furan aldehydes, and phenolic compounds, which are recognized as inhibitors of yeast during ethanolic fermentation. The results indicate that enzymes can be produced from the stillage stream as a high-value coproduct in second-generation bioethanol plants in a way that also facilitates recirculation of process water. PMID:19251882

  19. Bioethanol a Microbial Biofuel Metabolite; New Insights of Yeasts Metabolic Engineering

    Directory of Open Access Journals (Sweden)

    Khaled A. Selim

    2018-03-01

    Full Text Available Scarcity of the non-renewable energy sources, global warming, environmental pollution, and raising the cost of petroleum are the motive for the development of renewable, eco-friendly fuels production with low costs. Bioethanol production is one of the promising materials that can subrogate the petroleum oil, and it is considered recently as a clean liquid fuel or a neutral carbon. Diverse microorganisms such as yeasts and bacteria are able to produce bioethanol on a large scale, which can satisfy our daily needs with cheap and applicable methods. Saccharomyces cerevisiae and Pichia stipitis are two of the pioneer yeasts in ethanol production due to their abilities to produce a high amount of ethanol. The recent focus is directed towards lignocellulosic biomass that contains 30–50% cellulose and 20–40% hemicellulose, and can be transformed into glucose and fundamentally xylose after enzymatic hydrolysis. For this purpose, a number of various approaches have been used to engineer different pathways for improving the bioethanol production with simultaneous fermentation of pentose and hexoses sugars in the yeasts. These approaches include metabolic and flux analysis, modeling and expression analysis, followed by targeted deletions or the overexpression of key genes. In this review, we highlight and discuss the current status of yeasts genetic engineering for enhancing bioethanol production, and the conditions that influence bioethanol production.

  20. Reviving the carbohydrate economy via multi-product lignocellulose biorefineries.

    Science.gov (United States)

    Zhang, Y-H Percival

    2008-05-01

    Before the industrial revolution, the global economy was largely based on living carbon from plants. Now the economy is mainly dependent on fossil fuels (dead carbon). Biomass is the only sustainable bioresource that can provide sufficient transportation fuels and renewable materials at the same time. Cellulosic ethanol production from less costly and most abundant lignocellulose is confronted with three main obstacles: (1) high processing costs (dollars /gallon of ethanol), (2) huge capital investment (dollars approximately 4-10/gallon of annual ethanol production capacity), and (3) a narrow margin between feedstock and product prices. Both lignocellulose fractionation technology and effective co-utilization of acetic acid, lignin and hemicellulose will be vital to the realization of profitable lignocellulose biorefineries, since co-product revenues would increase the margin up to 6.2-fold, where all purified lignocellulose co-components have higher selling prices (> approximately 1.0/kg) than ethanol ( approximately 0.5/kg of ethanol). Isolation of large amounts of lignocellulose components through lignocellulose fractionation would stimulate R&D in lignin and hemicellulose applications, as well as promote new markets for lignin- and hemicellulose-derivative products. Lignocellulose resource would be sufficient to replace significant fractionations (e.g., 30%) of transportation fuels through liquid biofuels, internal combustion engines in the short term, and would provide 100% transportation fuels by sugar-hydrogen-fuel cell systems in the long term.

  1. Chemical genomic guided engineering of gamma-valerolactone tolerant yeast.

    Science.gov (United States)

    Bottoms, Scott; Dickinson, Quinn; McGee, Mick; Hinchman, Li; Higbee, Alan; Hebert, Alex; Serate, Jose; Xie, Dan; Zhang, Yaoping; Coon, Joshua J; Myers, Chad L; Landick, Robert; Piotrowski, Jeff S

    2018-01-12

    Gamma valerolactone (GVL) treatment of lignocellulosic bomass is a promising technology for degradation of biomass for biofuel production; however, GVL is toxic to fermentative microbes. Using a combination of chemical genomics with the yeast (Saccharomyces cerevisiae) deletion collection to identify sensitive and resistant mutants, and chemical proteomics to monitor protein abundance in the presence of GVL, we sought to understand the mechanism toxicity and resistance to GVL with the goal of engineering a GVL-tolerant, xylose-fermenting yeast. Chemical genomic profiling of GVL predicted that this chemical affects membranes and membrane-bound processes. We show that GVL causes rapid, dose-dependent cell permeability, and is synergistic with ethanol. Chemical genomic profiling of GVL revealed that deletion of the functionally related enzymes Pad1p and Fdc1p, which act together to decarboxylate cinnamic acid and its derivatives to vinyl forms, increases yeast tolerance to GVL. Further, overexpression of Pad1p sensitizes cells to GVL toxicity. To improve GVL tolerance, we deleted PAD1 and FDC1 in a xylose-fermenting yeast strain. The modified strain exhibited increased anaerobic growth, sugar utilization, and ethanol production in synthetic hydrolysate with 1.5% GVL, and under other conditions. Chemical proteomic profiling of the engineered strain revealed that enzymes involved in ergosterol biosynthesis were more abundant in the presence of GVL compared to the background strain. The engineered GVL strain contained greater amounts of ergosterol than the background strain. We found that GVL exerts toxicity to yeast by compromising cellular membranes, and that this toxicity is synergistic with ethanol. Deletion of PAD1 and FDC1 conferred GVL resistance to a xylose-fermenting yeast strain by increasing ergosterol accumulation in aerobically grown cells. The GVL-tolerant strain fermented sugars in the presence of GVL levels that were inhibitory to the unmodified strain

  2. Fermentative hydrogen production from agroindustrial lignocellulosic substrates

    Science.gov (United States)

    Reginatto, Valeria; Antônio, Regina Vasconcellos

    2015-01-01

    To achieve economically competitive biological hydrogen production, it is crucial to consider inexpensive materials such as lignocellulosic substrate residues derived from agroindustrial activities. It is possible to use (1) lignocellulosic materials without any type of pretreatment, (2) lignocellulosic materials after a pretreatment step, and (3) lignocellulosic materials hydrolysates originating from a pretreatment step followed by enzymatic hydrolysis. According to the current literature data on fermentative H2 production presented in this review, thermophilic conditions produce H2 in yields approximately 75% higher than those obtained in mesophilic conditions using untreated lignocellulosic substrates. The average H2 production from pretreated material is 3.17 ± 1.79 mmol of H2/g of substrate, which is approximately 50% higher compared with the average yield achieved using untreated materials (2.17 ± 1.84 mmol of H2/g of substrate). Biological pretreatment affords the highest average yield 4.54 ± 1.78 mmol of H2/g of substrate compared with the acid and basic pretreatment - average yields of 2.94 ± 1.85 and 2.41 ± 1.52 mmol of H2/g of substrate, respectively. The average H2 yield from hydrolysates, obtained from a pretreatment step and enzymatic hydrolysis (3.78 ± 1.92 mmol of H2/g), was lower compared with the yield of substrates pretreated by biological methods only, demonstrating that it is important to avoid the formation of inhibitors generated by chemical pretreatments. Based on this review, exploring other microorganisms and optimizing the pretreatment and hydrolysis conditions can make the use of lignocellulosic substrates a sustainable way to produce H2. PMID:26273246

  3. Dilute acid/metal salt hydrolysis of lignocellulosics

    Science.gov (United States)

    Nguyen, Quang A.; Tucker, Melvin P.

    2002-01-01

    A modified dilute acid method of hydrolyzing the cellulose and hemicellulose in lignocellulosic material under conditions to obtain higher overall fermentable sugar yields than is obtainable using dilute acid alone, comprising: impregnating a lignocellulosic feedstock with a mixture of an amount of aqueous solution of a dilute acid catalyst and a metal salt catalyst sufficient to provide higher overall fermentable sugar yields than is obtainable when hydrolyzing with dilute acid alone; loading the impregnated lignocellulosic feedstock into a reactor and heating for a sufficient period of time to hydrolyze substantially all of the hemicellulose and greater than 45% of the cellulose to water soluble sugars; and recovering the water soluble sugars.

  4. Profiling microbial lignocellulose degradation and utilization by emergent omics technologies.

    Science.gov (United States)

    Rosnow, Joshua J; Anderson, Lindsey N; Nair, Reji N; Baker, Erin S; Wright, Aaron T

    2017-08-01

    The use of plant materials to generate renewable biofuels and other high-value chemicals is the sustainable and preferable option, but will require considerable improvements to increase the rate and efficiency of lignocellulose depolymerization. This review highlights novel and emerging technologies that are being developed and deployed to characterize the process of lignocellulose degradation. The review will also illustrate how microbial communities deconstruct and metabolize lignocellulose by identifying the necessary genes and enzyme activities along with the reaction products. These technologies include multi-omic measurements, cell sorting and isolation, nuclear magnetic resonance spectroscopy (NMR), activity-based protein profiling, and direct measurement of enzyme activity. The recalcitrant nature of lignocellulose necessitates the need to characterize the methods microbes employ to deconstruct lignocellulose to inform new strategies on how to greatly improve biofuel conversion processes. New technologies are yielding important insights into microbial functions and strategies employed to degrade lignocellulose, providing a mechanistic blueprint in order to advance biofuel production.

  5. An efficient Azorean thermophilic consortium for lignocellulosic biomass degradation

    OpenAIRE

    Martins, Rita; Teixeira, Mário; Toubarro, Duarte; Simões, Nelson; Domingues, Lucília; Teixeira, J. A.

    2015-01-01

    [Excerpt] Lignocellulosic plant biomass is being envisioned by biorefinery industry as an alternative to current petroleum platform because of the large scale availability, low cost and environmentally benign production. The industrial bioprocessing designed to transform lignocellulosic biomass into biofuels are harsh and the enzymatic reactions may be severely compromised reducing the production of fermentable sugars from lignocellulosic biomass. Thermophilic bacteria consortium are a potent...

  6. Pretreatments to enhance the digestibility of lignocellulosic biomass

    NARCIS (Netherlands)

    Hendriks, A.T.W.M.; Zeeman, G.

    2009-01-01

    Lignocellulosic biomass represents a rather unused source for biogas and ethanol production. Many factors, like lignin content, crystallinity of cellulose, and particle size, limit the digestibility of the hemicellulose and cellulose present in the lignocellulosic biomass. Pretreatments have as a

  7. Pentose utilization in yeasts: Physiology and biochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Jeppson, H.

    1996-04-01

    The fermentive performance of bacteria, yeasts, and filamentous fungi was investigated in a pentose (xylose)-rich lignocellulosic hydrolyzate. The filamentous fungus Fusarium oxysporum and the xylose-fermenting yeast Pichia stipitis were found to be very sensitive to the inhibiting hydrolyzate. Recombinant xylose-utilizing Saccharomyces cerevisiae showed very poor ethanol formation from xylose; xylitol being the major product formed. The highest ethanol yields were obtained with recombinant Escherichia coli KO11, however, for maximal ethanol yield detoxification of the hydrolyzate was required. The influence of oxygen on the regulation of carbohydrate metabolism in the xylose-fermenting yeast P. stipitis CBS 6054 was investigated. A low and well-controlled level of oxygenation has been found to be required for efficient ethanol formation from xylose by the xylose-fermenting yeasts. The requirement of oxygen is frequently ascribed to the apparent redox imbalance which develops under anaerobic conditions due to the difference in co-factor utilization of the two first enzymes in the xylose metabolism, further reflected in xylitol excretion. However, a low and well controlled level of oxygenation for maximal ethanol production from glucose was also demonstrated, suggesting that the oxygen requirement is not only due to the dual co-factor utilization, but also serves other purposes. Cyanide-insensitive and salicyl hydroxamic acid-sensitive respiration (CIR) was found in P. stipitis. CIR is suggested to act as a redox sink preventing xylitol formation in P. stipitis under oxygen-limited xylose fermentations. Xylitol metabolism by P. stipitis CBS 6054 was strictly respiratory and ethanol was not formed under any conditions. The absence of ethanol formation was not due to a lack of fermentative enzymes, since the addition of glucose to xylitol-pregrown cells resulted in ethanol formation. 277 refs, 5 figs, 7 tabs

  8. Renewable biofuels bioconversion of lignocellulosic biomass by microbial community

    CERN Document Server

    Rana, Vandana

    2017-01-01

    This book offers a complete introduction for novices to understand key concepts of biocatalysis and how to produce in-house enzymes that can be used for low-cost biofuels production. The authors discuss the challenges involved in the commercialization of the biofuel industry, given the expense of commercial enzymes used for lignocellulose conversion. They describe the limitations in the process, such as complexity of lignocellulose structure, different microbial communities’ actions and interactions for degrading the recalcitrant structure of lignocellulosic materials, hydrolysis mechanism and potential for bio refinery. Readers will gain understanding of the key concepts of microbial catalysis of lignocellulosic biomass, process complexities and selection of microbes for catalysis or genetic engineering to improve the production of bioethanol or biofuel.

  9. Insights from the Fungus Fusarium oxysporum Point to High Affinity Glucose Transporters as Targets for Enhancing Ethanol Production from Lignocellulose

    Science.gov (United States)

    Ali, Shahin S.; Nugent, Brian; Mullins, Ewen; Doohan, Fiona M.

    2013-01-01

    Ethanol is the most-widely used biofuel in the world today. Lignocellulosic plant biomass derived from agricultural residue can be converted to ethanol via microbial bioprocessing. Fungi such as Fusarium oxysporum can simultaneously saccharify straw to sugars and ferment sugars to ethanol. But there are many bottlenecks that need to be overcome to increase the efficacy of microbial production of ethanol from straw, not least enhancement of the rate of fermentation of both hexose and pentose sugars. This research tested the hypothesis that the rate of sugar uptake by F. oxysporum would enhance the ethanol yields from lignocellulosic straw and that high affinity glucose transporters can enhance ethanol yields from this substrate. We characterized a novel hexose transporter (Hxt) from this fungus. The F. oxysporum Hxt represents a novel transporter with homology to yeast glucose signaling/transporter proteins Rgt2 and Snf3, but it lacks their C-terminal domain which is necessary for glucose signalling. Its expression level decreased with increasing glucose concentration in the medium and in a glucose uptake study the Km(glucose) was 0.9 mM, which indicated that the protein is a high affinity glucose transporter. Post-translational gene silencing or over expression of the Hxt in F. oxysporum directly affected the glucose and xylose transport capacity and ethanol yielded by F. oxysporum from straw, glucose and xylose. Thus we conclude that this Hxt has the capacity to transport both C5 and C6 sugars and to enhance ethanol yields from lignocellulosic material. This study has confirmed that high affinity glucose transporters are ideal candidates for improving ethanol yields from lignocellulose because their activity and level of expression is high in low glucose concentrations, which is very common during the process of consolidated processing. PMID:23382943

  10. Insights from the fungus Fusarium oxysporum point to high affinity glucose transporters as targets for enhancing ethanol production from lignocellulose.

    Directory of Open Access Journals (Sweden)

    Shahin S Ali

    Full Text Available Ethanol is the most-widely used biofuel in the world today. Lignocellulosic plant biomass derived from agricultural residue can be converted to ethanol via microbial bioprocessing. Fungi such as Fusarium oxysporum can simultaneously saccharify straw to sugars and ferment sugars to ethanol. But there are many bottlenecks that need to be overcome to increase the efficacy of microbial production of ethanol from straw, not least enhancement of the rate of fermentation of both hexose and pentose sugars. This research tested the hypothesis that the rate of sugar uptake by F. oxysporum would enhance the ethanol yields from lignocellulosic straw and that high affinity glucose transporters can enhance ethanol yields from this substrate. We characterized a novel hexose transporter (Hxt from this fungus. The F. oxysporum Hxt represents a novel transporter with homology to yeast glucose signaling/transporter proteins Rgt2 and Snf3, but it lacks their C-terminal domain which is necessary for glucose signalling. Its expression level decreased with increasing glucose concentration in the medium and in a glucose uptake study the Km((glucose was 0.9 mM, which indicated that the protein is a high affinity glucose transporter. Post-translational gene silencing or over expression of the Hxt in F. oxysporum directly affected the glucose and xylose transport capacity and ethanol yielded by F. oxysporum from straw, glucose and xylose. Thus we conclude that this Hxt has the capacity to transport both C5 and C6 sugars and to enhance ethanol yields from lignocellulosic material. This study has confirmed that high affinity glucose transporters are ideal candidates for improving ethanol yields from lignocellulose because their activity and level of expression is high in low glucose concentrations, which is very common during the process of consolidated processing.

  11. Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes.

    Science.gov (United States)

    Bhalla, Aditya; Bansal, Namita; Kumar, Sudhir; Bischoff, Kenneth M; Sani, Rajesh K

    2013-01-01

    Second-generation feedstock, especially nonfood lignocellulosic biomass is a potential source for biofuel production. Cost-intensive physical, chemical, biological pretreatment operations and slow enzymatic hydrolysis make the overall process of lignocellulosic conversion into biofuels less economical than available fossil fuels. Lignocellulose conversions carried out at ≤ 50 °C have several limitations. Therefore, this review focuses on the importance of thermophilic bacteria and thermostable enzymes to overcome the limitations of existing lignocellulosic biomass conversion processes. The influence of high temperatures on various existing lignocellulose conversion processes and those that are under development, including separate hydrolysis and fermentation, simultaneous saccharification and fermentation, and extremophilic consolidated bioprocess are also discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Cellulase-lignin interactions in the enzymatic hydrolysis of lignocellulose

    Energy Technology Data Exchange (ETDEWEB)

    Rahikainen, J.

    2013-11-01

    Today, the production of transportation fuels and chemicals is heavily dependent on fossil carbon sources, such as oil and natural gas. Their limited availability and the environmental concerns arising from their use have driven the search for renewable alternatives. Lignocellulosic plant biomass is the most abundant, but currently underutilised, renewable carbon-rich resource for fuel and chemical production. Enzymatic degradation of structural polysaccharides in lignocellulose produces soluble carbohydrates that serve as ideal precursors for the production of a vast amount of different chemical compounds. The difficulty in full exploitation of lignocellulose for fuel and chemical production lies in the complex and recalcitrant structure of the raw material. Lignocellulose is mainly composed of structural polysaccharides, cellulose and hemicellulose, but also of lignin, which is an aromatic polymer. Enzymatic degradation of cellulose and hemicellulose is restricted by several substrate- and enzyme-related factors, among which lignin is considered as one of the most problematic issues. Lignin restricts the action of hydrolytic enzymes and enzyme binding onto lignin has been identified as a major inhibitory mechanism preventing efficient hydrolysis of lignocellulosic feedstocks. In this thesis, the interactions between cellulase enzymes and lignin-rich compounds were studied in detail and the findings reported in this work have the potential to help in controlling the harmful cellulase-lignin interactions, and thus improve the biochemical processing route from lignocellulose to fuels and chemicals.

  13. Fermented wheat powder induces the antioxidant and detoxifying system in primary rat hepatocytes.

    Science.gov (United States)

    La Marca, Margherita; Beffy, Pascale; Pugliese, Annalisa; Longo, Vincenzo

    2013-01-01

    Many plants exhibit antioxidant properties which may be useful in the prevention of oxidative stress reactions, such as those mediated by the formation of free radical species in different pathological situations. In recent years a number of studies have shown that whole grain products in particular have strong antioxidant activity. Primary cultures of rat hepatocytes were used to investigate whether and how a fermented powder of wheat (Lisosan G) is able to modulate antioxidant and detoxifying enzymes, and whether or not it can activate Nrf2 transcription factor or inhibit NF-kB activation. All of the antioxidant and detoxifying enzymes studied were significantly up-regulated by 0.7 mg/ml Lisosan G treatment. In particular, quinone oxidoreductase and heme oxygenase-1 were induced, although to different degrees, at the transcriptional, protein and/or activity levels by the treatment. As for the Nrf2 transcription factor, a partial translocation of its protein from the cytosol to the nucleus after 1 h of Lisosan G treatment was revealed by immunoblotting. Lisosan G was also observed to decrease H2O2-induced toxicity Taken together, these results show that this powder of wheat is an effective inducer of ARE/Nrf2-regulated antioxidant and detoxifying genes and has the potential to inhibit the translocation of NF-kB into the nucleus.

  14. Methods for producing extracted and digested products from pretreated lignocellulosic biomass

    Science.gov (United States)

    Chundawat, Shishir; Sousa, Leonardo Da Costa; Cheh, Albert M.; Balan; , Venkatesh; Dale, Bruce

    2017-05-16

    Methods for producing extracted and digested products from pretreated lignocellulosic biomass are provided. The methods include converting native cellulose I.sub..beta. to cellulose III.sub.I by pretreating the lignocellulosic biomass with liquid ammonia under certain conditions, and performing extracting or digesting steps on the pretreated/converted lignocellulosic biomass.

  15. Lignocellulosic Biomass: A Sustainable Bioenergy Source for the Future.

    Science.gov (United States)

    Fatma, Shabih; Hameed, Amir; Noman, Muhammad; Ahmed, Temoor; Shahid, Muhammad; Tariq, Mohsin; Sohail, Imran; Tabassum, Romana

    2018-01-01

    Increasing population and industrialization are continuously oppressing the existing energy resources and depleting the global fuel reservoirs. The elevated pollutions from the continuous consumption of non-renewable fossil fuels also seriously contaminating the surrounding environment. The use of alternate energy sources can be an environment-friendly solution to cope these challenges. Among the renewable energy sources biofuels (biomass-derived fuels) can serve as a better alternative to reduce the reliance on non-renewable fossil fuels. Bioethanol is one of the most widely consumed biofuels of today's world. The main objective of this review is to highlight the significance of lignocellulosic biomass as a potential source for the production of biofuels like bioethanol, biodiesel or biogas. We discuss the application of various methods for the bioconversion of lignocellulosic biomass to end products i.e. biofuels. The lignocellulosic biomass must be pretreated to disintegrate lignocellulosic complexes and to expose its chemical components for downstream processes. After pretreatment, the lignocellulosic biomass is then subjected to saccharification either via acidic or enzymatic hydrolysis. Thereafter, the monomeric sugars resulted from hydrolysis step are further processed into biofuel i.e. bioethanol, biodiesel or butanol etc. through the fermentation process. The fermented impure product is then purified through the distillation process to obtain pure biofuel. Renewable energy sources represent the potential fuel alternatives to overcome the global energy crises in a sustainable and eco-friendly manner. In future, biofuels may replenish the conventional non-renewable energy resources due to their renewability and several other advantages. Lignocellulosic biomass offers the most economical biomass to generate biofuels. However, extensive research is required for the commercial production of an efficient integrated biotransformation process for the production of

  16. PRETREATMENT TECHNOLOGIES IN BIOETHANOL PRODUCTION FROM LIGNOCELLULOSIC BIOMASS

    Directory of Open Access Journals (Sweden)

    Vanja Janušić

    2008-07-01

    Full Text Available Bioethanol is today most commonly produced from corn grain and sugar cane. It is expected that there will be limits to the supply of these raw materials in the near future. Therefore, lignocellulosic biomass, namely agricultural and forest waste, is seen as an attractive feedstock for future supplies of ethanol. Lignocellulosic biomass consists of lignin, hemicellulose and cellulose. Indeed, complexicity of the lignocellulosic biomass structure causes a pretreatment to be applied prior to cellulose and hemicellulose hydrolysis into fermentable sugars. Pretreatment technologies can be physical (mechanical comminution, pyrolysis, physico-chemical (steam explosion, ammonia fiber explosion, CO2 explosion, chemical (ozonolysis, acid hydrolysis, alkaline hydrolysis, oxidative delignification, organosolvent process and biological ones.

  17. A lignocellulosic ethanol strategy via nonenzymatic sugar production: process synthesis and analysis.

    Science.gov (United States)

    Han, Jeehoon; Luterbacher, Jeremy S; Alonso, David Martin; Dumesic, James A; Maravelias, Christos T

    2015-04-01

    The work develops a strategy for the production of ethanol from lignocellulosic biomass. In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to sugars using a γ-valerolactone (GVL) solvent containing a dilute acid catalyst. To effectively recover GVL for reuse as solvent and biomass-derived lignin for heat and power generation, separation subsystems, including a novel CO2-based extraction for the separation of sugars from GVL, lignin and humins have been designed. The sugars are co-fermented by yeast to produce ethanol. Furthermore, heat integration to reduce utility requirements is performed. It is shown that this strategy leads to high ethanol yields and the total energy requirements could be satisfied by burning the lignin. The integrated strategy using corn stover feedstock leads to a minimum selling price of $5 per gallon of gasoline equivalent, which suggests that it is a promising alternative to current biofuels production approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. From mannan to bioethanol: cell surface co-display of β-mannanase and β-mannosidase on yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Ishii, Jun; Okazaki, Fumiyoshi; Djohan, Apridah Cameliawati; Hara, Kiyotaka Y; Asai-Nakashima, Nanami; Teramura, Hiroshi; Andriani, Ade; Tominaga, Masahiro; Wakai, Satoshi; Kahar, Prihardi; Yopi; Prasetya, Bambang; Ogino, Chiaki; Kondo, Akihiko

    2016-01-01

    Mannans represent the largest hemicellulosic fraction in softwoods and also serve as carbohydrate stores in various plants. However, the utilization of mannans as sustainable resources has been less advanced in sustainable biofuel development. Based on a yeast cell surface-display technology that enables the immobilization of multiple enzymes on the yeast cell walls, we constructed a recombinant Saccharomyces cerevisiae strain that co-displays β-mannanase and β-mannosidase; this strain is expected to facilitate ethanol fermentation using mannan as a biomass source. Parental yeast S. cerevisiae assimilated mannose and glucose as monomeric sugars, producing ethanol from mannose. We constructed yeast strains that express tethered β-mannanase and β-mannosidase; co-display of the two enzymes on the cell surface was confirmed by immunofluorescence staining and enzyme activity assays. The constructed yeast cells successfully hydrolyzed 1,4-β-d-mannan and produced ethanol by assimilating the resulting mannose without external addition of enzymes. Furthermore, the constructed strain produced ethanol from 1,4-β-d-mannan continually during the third batch of repeated fermentation. Additionally, the constructed strain produced ethanol from ivory nut mannan; ethanol yield was improved by NaOH pretreatment of the substrate. We successfully displayed β-mannanase and β-mannosidase on the yeast cell surface. Our results clearly demonstrate the utility of the strain co-displaying β-mannanase and β-mannosidase for ethanol fermentation from mannan biomass. Thus, co-tethering β-mannanase and β-mannosidase on the yeast cell surface provides a powerful platform technology for yeast fermentation toward the production of bioethanol and other biochemicals from lignocellulosic materials containing mannan components.

  19. HAA1 and PRS3 overexpression boosts yeast tolerance towards acetic acid improving xylose or glucose consumption: unravelling the underlying mechanisms.

    Science.gov (United States)

    Cunha, Joana T; Costa, Carlos E; Ferraz, Luís; Romaní, Aloia; Johansson, Björn; Sá-Correia, Isabel; Domingues, Lucília

    2018-04-02

    Acetic acid tolerance and xylose consumption are desirable traits for yeast strains used in industrial biotechnological processes. In this work, overexpression of a weak acid stress transcriptional activator encoded by the gene HAA1 and a phosphoribosyl pyrophosphate synthetase encoded by PRS3 in a recombinant industrial Saccharomyces cerevisiae strain containing a xylose metabolic pathway was evaluated in the presence of acetic acid in xylose- or glucose-containing media. HAA1 or PRS3 overexpression resulted in superior yeast growth and higher sugar consumption capacities in the presence of 4 g/L acetic acid, and a positive synergistic effect resulted from the simultaneous overexpression of both genes. Overexpressing these genes also improved yeast adaptation to a non-detoxified hardwood hydrolysate with a high acetic acid content. Furthermore, the overexpression of HAA1 and/or PRS3 was found to increase the robustness of yeast cell wall when challenged with acetic acid stress, suggesting the involvement of the modulation of the cell wall integrity pathway. This study clearly shows HAA1 and/or, for the first time, PRS3 overexpression to play an important role in the improvement of industrial yeast tolerance towards acetic acid. The results expand the molecular toolbox and add to the current understanding of the mechanisms involved in higher acetic acid tolerance, paving the way for the further development of more efficient industrial processes.

  20. Effect of Lignocellulose Related Compounds on Microalgae Growth and Product Biosynthesis: A Review

    Directory of Open Access Journals (Sweden)

    Krystian Miazek

    2014-07-01

    Full Text Available Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated.

  1. Bioethanol from lignocellulosics: Status and perspectives in Canada.

    Science.gov (United States)

    Mabee, W E; Saddler, J N

    2010-07-01

    Canada has invested significantly in the development of a domestic bioethanol industry, and it is expected that bioethanol from lignocellulosics will become more desirable to the industry as it expands. Development of the Canadian industry to date is described in this paper, as are examples of domestic research programs focused on both bioconversion and thermochemical conversion to generate biofuels from lignocellulosic biomass. The availability of lignocellulosic residues from agricultural and forestry operations, and the potential biofuel production associated with these residues, is described. The policy tools used to develop the domestic bioethanol industry are explored. A residue-based process could greatly extend the potential of the bioethanol industry in Canada. It is estimated that bioethanol production from residual lignocellulosic feedstocks could provide up to 50% of Canada's 2006 transportation fuel demand, given ideal conversion and full access to these feedstocks. Utilizing lignocellulosic biomass will extend the geographic range of the bioethanol industry, and increase the stability and security of this sector by reducing the impact of localized disruptions in supply. Use of disturbance crops could add 9% to this figure, but not in a sustainable fashion. If pursued aggressively, energy crops ultimately could contribute bioethanol at a volume double that of Canada's gasoline consumption in 2006. This would move Canada towards greater transportation fuel independence and a larger role in the export of bioethanol to the global market. Copyright 2009 Elsevier Ltd. All rights reserved.

  2. Identification of Inhibitors in Lignocellulosic Slurries and Determination of Their Effect on Hydrocarbon-Producing Microorganisms

    Directory of Open Access Journals (Sweden)

    Shihui Yang

    2018-04-01

    Full Text Available The aim of this work was to identify inhibitors in pretreated lignocellulosic slurries, evaluate high-throughput screening strategies, and investigate the impact of inhibitors on potential hydrocarbon-producing microorganisms. Compounds present in slurries that could inhibit microbial growth were identified through a detailed analysis of saccharified slurries by applying a combination of approaches of high-performance liquid chromatography, GC-MS, LC-DAD-MS, and ICP-MS. Several high-throughput assays were then evaluated to generate toxicity profiles. Our results demonstrated that Bioscreen C was useful for analyzing bacterial toxicity but not for yeast. AlamarBlue reduction assay can be a useful high-throughput assay for both bacterial and yeast strains as long as medium components do not interfere with fluorescence measurements. In addition, this work identified two major inhibitors (furfural and ammonium acetate for three potential hydrocarbon-producing bacterial species that include Escherichia coli, Cupriavidus necator, and Rhodococcus opacus PD630, which are also the primary inhibitors for ethanologens. This study was strived to establish a pipeline to quantify inhibitory compounds in biomass slurries and high-throughput approaches to investigate the effect of inhibitors on microbial biocatalysts, which can be applied for various biomass slurries or hydrolyzates generated through different pretreatment and enzymatic hydrolysis processes or different microbial candidates.

  3. Thermophysical properties of lignocellulose: a cell-scale study down to 41 K.

    Science.gov (United States)

    Cheng, Zhe; Xu, Zaoli; Zhang, Lei; Wang, Xinwei

    2014-01-01

    Thermal energy transport is of great importance in lignocellulose pyrolysis for biofuels. The thermophysical properties of lignocellulose significantly affect the overall properties of bio-composites and the related thermal transport. In this work, cell-scale lignocellulose (mono-layer plant cells) is prepared to characterize their thermal properties from room temperature down to ∼ 40 K. The thermal conductivities of cell-scale lignocellulose along different directions show a little anisotropy due to the cell structure anisotropy. It is found that with temperature going down, the volumetric specific heat of the lignocellulose shows a slower decreasing trend against temperature than microcrystalline cellulose, and its value is always higher than that of microcrystalline cellulose. The thermal conductivity of lignocellulose decreases with temperature from 243 K to 317 K due to increasing phonon-phonon scatterings. From 41 K to 243 K, the thermal conductivity rises with temperature and its change mainly depends on the heat capacity's change.

  4. Thermophysical properties of lignocellulose: a cell-scale study down to 41 K.

    Directory of Open Access Journals (Sweden)

    Zhe Cheng

    Full Text Available Thermal energy transport is of great importance in lignocellulose pyrolysis for biofuels. The thermophysical properties of lignocellulose significantly affect the overall properties of bio-composites and the related thermal transport. In this work, cell-scale lignocellulose (mono-layer plant cells is prepared to characterize their thermal properties from room temperature down to ∼ 40 K. The thermal conductivities of cell-scale lignocellulose along different directions show a little anisotropy due to the cell structure anisotropy. It is found that with temperature going down, the volumetric specific heat of the lignocellulose shows a slower decreasing trend against temperature than microcrystalline cellulose, and its value is always higher than that of microcrystalline cellulose. The thermal conductivity of lignocellulose decreases with temperature from 243 K to 317 K due to increasing phonon-phonon scatterings. From 41 K to 243 K, the thermal conductivity rises with temperature and its change mainly depends on the heat capacity's change.

  5. Occurrence of Priming in the Degradation of Lignocellulose in Marine Sediments.

    Science.gov (United States)

    Gontikaki, Evangelia; Thornton, Barry; Cornulier, Thomas; Witte, Ursula

    2015-01-01

    More than 50% of terrestrially-derived organic carbon (terrOC) flux from the continents to the ocean is remineralised in the coastal zone despite its perceived high refractivity. The efficient degradation of terrOC in the marine environment could be fuelled by labile marine-derived material, a phenomenon known as "priming effect", but experimental data to confirm this mechanism are lacking. We tested this hypothesis by treating coastal sediments with 13C-lignocellulose, as a proxy for terrOC, with and without addition of unlabelled diatom detritus that served as the priming inducer. The occurrence of priming was assessed by the difference in lignocellulose mineralisation between diatom-amended treatments and controls in aerobic sediment slurries. Priming of lignocellulose degradation was observed only at the initial stages of the experiment (day 7) and coincided with overall high microbial activity as exemplified by total CO2 production. Lignocellulose mineralisation did not differ consistently between diatom treatments and control for the remaining experimental time (days 14-28). Based on this pattern, we hypothesize that the faster initiation of lignocellulose mineralisation in diatom-amended treatments is attributed to the decomposition of accessible polysaccharide components within the lignocellulose complex by activated diatom degraders. The fact that diatom-degraders contributed to lignocellulose degradation was also supported by the different patterns in 13C-enrichment of phospholipid fatty acids between treatments. Although we did not observe differences between treatments in the total quantity of respired lignocellulose at the end of the experiment, differences in timing could be important in natural ecosystems where the amount of time that a certain compound is subject to aerobic degradation before burial to deeper anoxic sediments may be limited.

  6. Unravel lipid accumulation mechanism in oleaginous yeast through single cell systems biology study

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Shiyou; Xiaoliang, Xie

    2017-12-18

    Replacement of petroleum with advanced biofuels is critical for environmental protection needs, sustainable and secure energy demands, and economic development. Bacteria, yeasts, and fungi can naturally synthesize fatty acids, isoprenoids, or polyalkanoates for energy storage, and therefore are currently explored for hydrocarbon fuel production. Oleaginous yeasts can accumulate high levels of lipids in the form of triacylglycerols (TAGs) when encountering stress conditions or imbalanced growth (e.g., growing under excess carbon sources and limited nitrogen conditions). Advantages of using oleaginous yeast as cell factories include short duplication time (< 1 hour), high yield of intracellular droplets, and easy scale-up for industrial production. Currently, various oleaginous yeasts (e.g., Yarrowia, Candida, Rhodotorulla, Rhodosporidium, Cryptococcus, Trichosporon, and Lipomyces) have been developed as potential advanced biofuel producers. Oleaginous yeast lipid production has two phases: 1) growth phase, where cells utilize the carbon and nitrogen source to build up biomass. And 2) lipid accumulation phase, where they convert carbon source in media into the storage lipid body. (i.e. a high carbon to nitrogen ratio leads to high lipid production). The lipid production varies dramatically when different sugar, e.g. glucose, xylose is used as carbon source. The efficient utilization of all monomeric sugars of hexoses and pentoses from various lignocellulosic biomass processing approaches is the key for economic lignocellulosic biofuel production. In this project, we explored lipid production in oleaginous yeast under different nitrogen and sugar conditions at the single-cell level. To understand the lipid production mechanism and identify genetic features responsive to lipid accumulation in the presence of pentose and nitrogen, we developed an automated chemical imaging and single-cell transcriptomics method to correlate the lipid accumulation with the

  7. Protein Engineering of GRE2 from Saccharomyces cerevisiae for Enhanced Detoxification of 5-Hydroxymethyl Furfural

    Science.gov (United States)

    Furfural and 5-hydroxymethylfurfural (HMF) are representative inhibitors generated by lignocellulosic biomass pretreatment such as dilute acid hydrolysis that inhibit microbial growth and subsequent fermentation. It is possible to in situ detoxify these inhibitory compounds using tolerant Saccharomy...

  8. Sustaining fermentation in high-gravity ethanol production by feeding yeast to a temperature-profiled multifeed simultaneous saccharification and co-fermentation of wheat straw.

    Science.gov (United States)

    Westman, Johan O; Wang, Ruifei; Novy, Vera; Franzén, Carl Johan

    2017-01-01

    Considerable progress is being made in ethanol production from lignocellulosic feedstocks by fermentation, but negative effects of inhibitors on fermenting microorganisms are still challenging. Feeding preadapted cells has shown positive effects by sustaining fermentation in high-gravity simultaneous saccharification and co-fermentation (SSCF). Loss of cell viability has been reported in several SSCF studies on different substrates and seems to be the main reason for the declining ethanol production toward the end of the process. Here, we investigate how the combination of yeast preadaptation and feeding, cell flocculation, and temperature reduction improves the cell viability in SSCF of steam pretreated wheat straw. More than 50% cell viability was lost during the first 24 h of high-gravity SSCF. No beneficial effects of adding selected nutrients were observed in shake flask SSCF. Ethanol concentrations greater than 50 g L -1 led to significant loss of viability and prevented further fermentation in SSCF. The benefits of feeding preadapted yeast cells were marginal at later stages of SSCF. Yeast flocculation did not improve the viability but simplified cell harvest and improved the feasibility of the cell feeding strategy in demo scale. Cultivation at 30 °C instead of 35 °C increased cell survival significantly on solid media containing ethanol and inhibitors. Similarly, in multifeed SSCF, cells maintained the viability and fermentation capacity when the temperature was reduced from 35 to 30 °C during the process, but hydrolysis yields were compromised. By combining the yeast feeding and temperature change, an ethanol concentration of 65 g L -1 , equivalent to 70% of the theoretical yield, was obtained in multifeed SSCF on pretreated wheat straw. In demo scale, the process with flocculating yeast and temperature profile resulted in 5% (w/w) ethanol, equivalent to 53% of the theoretical yield. Multifeed SSCF was further developed by means of a

  9. Lignocellulose fermentation and residual solids characterization for senescent switchgrass fermentation by Clostridium thermocellum in the presence and absence of continuous in situ ball-milling

    Energy Technology Data Exchange (ETDEWEB)

    Balch, Michael L.; Holwerda, Evert K.; Davis, Mark F.; Sykes, Robert W.; Happs, Renee M.; Kumar, Rajeev; Wyman, Charles E.; Lynd, Lee R.

    2017-04-12

    Milling during lignocellulosic fermentation, henceforth referred to as cotreatment, is investigated as an alternative to thermochemical pretreatment as a means of enhancing biological solubilization of lignocellulose. We investigate the impact of milling on soluble substrate fermentation by Clostridium thermocellum with comparison to yeast, document solubilization for fermentation of senescent switchgrass with and without ball milling, and characterize residual solids. Soluble substrate fermentation by C. thermocellum proceeded readily in the presence of continuous ball milling but was completely arrested for yeast. Total fractional carbohydrate solubilization achieved after fermentation of senescent switchgrass by C. thermocellum for 5 days was 0.45 without cotreatment or pretreatment, 0.81 with hydrothermal pretreatment (200 degrees C, 15 minutes, severity 4.2), and 0.88 with cotreatment. Acetate and ethanol were the main fermentation products, and were produced at similar ratios with and without cotreatment. Analysis of solid residues was undertaken using molecular beam mass spectrometry (PyMBMS) and solid-state nuclear magnetic resonance spectroscopy (NMR) in order to provide insight into changes in plant cell walls during processing via various modes. The structure of lignin present in residual solids remaining after fermentation with cotreatment appeared to change little, with substantially greater changes observed for hydrothermal pretreatment - particularly with respect to formation of C-C bonds. The observation of high solubilization with little apparent modification of the residue is consistent with cotreatment enhancing solubilization primarily by increasing the access of saccharolytic enzymes to the feedstock, and C. thermocellum being able to attack all the major linkages in cellulosic biomass provided that these linkages are accessible.

  10. Treatment of the lignocellulosic biomass by the gamma ray and its effect on lignin degradation

    International Nuclear Information System (INIS)

    El Abdi, Ines

    2009-01-01

    The development of alternative energies requires many research effort, with an aim of exploiting the lignocellulosic biomass. In fact, the stage of pretreatment makes it possible to facilitate the hydrolysis of the cellulose fractions, to give fermentable sugars by yeasts. However, several methods of pretreatment were identified, among them the treatment by the gamma rays. In this context, we have studied initially the effect of the gamma irradiation on the lignin degradation and on second place we added to the irradiation the treatment by dilute acid in order to optimize the rate of sugars. Thus, from 20 KGy there is a good degradation of lignins to give polyphenols components for about 4 Mg per gram of vegetable matter. However, the irradiation with 100KGy plus the acid treatment 1% has made possible to release 80% of fermentable sugars. (Author)

  11. Textile/metal-organic-framework composites as self-detoxifying filters for chemical-warfare agents.

    Science.gov (United States)

    López-Maya, Elena; Montoro, Carmen; Rodríguez-Albelo, L Marleny; Aznar Cervantes, Salvador D; Lozano-Pérez, A Abel; Cenís, José Luis; Barea, Elisa; Navarro, Jorge A R

    2015-06-01

    The current technology of air-filtration materials for protection against highly toxic chemicals, that is, chemical-warfare agents, is mainly based on the broad and effective adsorptive properties of hydrophobic activated carbons. However, adsorption does not prevent these materials from behaving as secondary emitters once they are contaminated. Thus, the development of efficient self-cleaning filters is of high interest. Herein, we report how we can take advantage of the improved phosphotriesterase catalytic activity of lithium alkoxide doped zirconium(IV) metal-organic framework (MOF) materials to develop advanced self-detoxifying adsorbents of chemical-warfare agents containing hydrolysable P-F, P-O, and C-Cl bonds. Moreover, we also show that it is possible to integrate these materials onto textiles, thereby combining air-permeation properties of the textiles with the self-detoxifying properties of the MOF material. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Occurrence of Priming in the Degradation of Lignocellulose in Marine Sediments.

    Directory of Open Access Journals (Sweden)

    Evangelia Gontikaki

    Full Text Available More than 50% of terrestrially-derived organic carbon (terrOC flux from the continents to the ocean is remineralised in the coastal zone despite its perceived high refractivity. The efficient degradation of terrOC in the marine environment could be fuelled by labile marine-derived material, a phenomenon known as "priming effect", but experimental data to confirm this mechanism are lacking. We tested this hypothesis by treating coastal sediments with 13C-lignocellulose, as a proxy for terrOC, with and without addition of unlabelled diatom detritus that served as the priming inducer. The occurrence of priming was assessed by the difference in lignocellulose mineralisation between diatom-amended treatments and controls in aerobic sediment slurries. Priming of lignocellulose degradation was observed only at the initial stages of the experiment (day 7 and coincided with overall high microbial activity as exemplified by total CO2 production. Lignocellulose mineralisation did not differ consistently between diatom treatments and control for the remaining experimental time (days 14-28. Based on this pattern, we hypothesize that the faster initiation of lignocellulose mineralisation in diatom-amended treatments is attributed to the decomposition of accessible polysaccharide components within the lignocellulose complex by activated diatom degraders. The fact that diatom-degraders contributed to lignocellulose degradation was also supported by the different patterns in 13C-enrichment of phospholipid fatty acids between treatments. Although we did not observe differences between treatments in the total quantity of respired lignocellulose at the end of the experiment, differences in timing could be important in natural ecosystems where the amount of time that a certain compound is subject to aerobic degradation before burial to deeper anoxic sediments may be limited.

  13. Bio-production of a polyalcohol (xylitol) from lignocellulosic resources : a review

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani, M.; Tabil, L.; Panigrahi, S. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Agricultural and Bioresource Engineering

    2006-07-01

    Lignocellulosic materials that are supplied from several sources at a low price can be utilized as feedstock for chemicals and bio-products. Xylitol is a high value polyalcohol produced by the reduction of D-xylose. It has many advantageous properties, such as low-calorie sweetening power. Due to its higher yield and because downstream processing is expected to be less costly, biotechnological production of xylitol is often more attractive than the chemical method of catalytic hydrogenation. Studies about the bio-production of xylitol, have been mostly focused on establishing the operational parameters and the process options that maximize its yield and productivity in free cell systems. However, some gaps in knowledge exist regarding this bioconversion process in immobilized cell systems and choosing an appropriate carrier for biocatalysts in a fermentation medium. This paper reviewed the metabolism of xylose by microorganisms, variables and process parameters affecting bioconversion of xylose to xylitol in defined media and complex media of lignocellulosic hydrolysates using free and immobilized cell systems. It discussed the natural occurrence, chemical structure, and physical properties of xylitol. Methods of production were discussed, including solid-liquid extraction; chemical production of xylitol; microbial production of xylitol; production of xylitol by bacteria; production of xylitol by molds; and production of xylitol by yeasts. The paper also discussed the parameters of fermentation, including xylose concentration; carbon source; nitrogen source; inoculum age and concentration; aeration rate; and temperature and pH. The production of xylitol from hemicellulose hydrolysate was also discussed along with immobilized-cell fermentation and xylitol recovery from fermented hydrolysate. It was concluded that purification and recovery of xylitol are the primary challenges related to this process, and a successful fermentation using immobilized cell system could

  14. Co-fermentation using Recombinant Saccharomyces cerevisiae Yeast Strains Hyper-secreting Different Cellulases for the Production of Cellulosic Bioethanol.

    Science.gov (United States)

    Lee, Cho-Ryong; Sung, Bong Hyun; Lim, Kwang-Mook; Kim, Mi-Jin; Sohn, Min Jeong; Bae, Jung-Hoon; Sohn, Jung-Hoon

    2017-06-30

    To realize the economical production of ethanol and other bio-based chemicals from lignocellulosic biomass by consolidated bioprocessing (CBP), various cellulases from different sources were tested to improve the level of cellulase secretion in the yeast Saccharomyces cerevisiae by screening an optimal translational fusion partner (TFP) as both a secretion signal and fusion partner. Among them, four indispensable cellulases for cellulose hydrolysis, including Chaetomium thermophilum cellobiohydrolase (CtCBH1), Chrysosporium lucknowense cellobiohydrolase (ClCBH2), Trichoderma reesei endoglucanase (TrEGL2), and Saccharomycopsis fibuligera β-glucosidase (SfBGL1), were identified to be highly secreted in active form in yeast. Despite variability in the enzyme levels produced, each recombinant yeast could secrete approximately 0.6-2.0 g/L of cellulases into the fermentation broth. The synergistic effect of the mixed culture of the four strains expressing the essential cellulases with the insoluble substrate Avicel and several types of cellulosic biomass was demonstrated to be effective. Co-fermentation of these yeast strains produced approximately 14 g/L ethanol from the pre-treated rice straw containing 35 g/L glucan with 3-fold higher productivity than that of wild type yeast using a reduced amount of commercial cellulases. This process will contribute to the cost-effective production of bioenergy such as bioethanol and biochemicals from cellulosic biomass.

  15. Engineering Ligninolytic Consortium for Bioconversion of Lignocelluloses to Ethanol and Chemicals.

    Science.gov (United States)

    Bilal, Muhammad; Nawaz, Muhammad Zohaib; Iqbal, Hafiz M N; Hou, Jialin; Mahboob, Shahid; Al-Ghanim, Khalid A; Cheng, Hairong

    2018-01-01

    Rising environmental concerns and recent global scenario of cleaner production and consumption are leading to the design of green industrial processes to produce alternative fuels and chemicals. Although bioethanol is one of the most promising and eco-friendly alternatives to fossil fuels yet its production from food and feed has received much negative criticism. The main objective of this study was to present the noteworthy potentialities of lignocellulosic biomass as an enormous and renewable biological resource. The particular focus was also given on engineering ligninolytic consortium for bioconversion of lignocelluloses to ethanol and chemicals on sustainable and environmentally basis. Herein, an effort has been made to extensively review, analyze and compile salient information related to the topic of interest. Several authentic bibliographic databases including PubMed, Scopus, Elsevier, Springer, Bentham Science and other scientific databases were searched with utmost care, and inclusion/ exclusion criterion was adopted to appraise the quality of retrieved peer-reviewed research literature. Bioethanol production from lignocellulosic biomass can largely satisfy the possible inconsistency of first-generation ethanol since it utilizes inedible lignocellulosic feedstocks, primarily sourced from agriculture and forestry wastes. Two major polysaccharides in lignocellulosic biomass namely, cellulose and hemicellulose constitute a complex lignocellulosic network by connecting with lignin, which is highly recalcitrant to depolymerization. Several attempts have been made to reduce the cost involved in the process through improving the pretreatment process. While, the ligninolytic enzymes of white rot fungi (WRF) including laccase, lignin peroxidase (LiP), and manganese peroxidase (MnP) have appeared as versatile biocatalysts for delignification of several lignocellulosic residues. The first part of the review is mainly focused on engineering ligninolytic consortium

  16. Hydrothermal pretreatment and enzymatic hydrolysis of mixed green and woody lignocellulosics from arid regions

    DEFF Research Database (Denmark)

    Ashraf, Muhammad Tahir; Thomsen, Mette Hedegaard; Schmidt, Jens Ejbye

    2017-01-01

    Utilization of multi-specie feedstocks is imperative for application of lignocellulosic biorefineries in arid regions. Different lignocellulosic residues vary in composition and anatomical features. Pretreatment and enzymatic hydrolysis are two processes at the front end of any lignocellulosics...... biorefinery applying biochemical pathway, and have to efficiently deal with the variance in the feedstock composition and properties. However, there is limited knowledge about effect of mixing different lignocellulosics on pretreatment and enzymatic hydrolysis yields. In this study effect of mixing...... on the yields from hydrothermal pretreatment and enzymatic hydrolysis was analyzed by mixing three different lignocellulosic residues — Bermuda grass, Jasmine hedges, and date palm fronds. Results showed that the individual and the mixed lignocellulosics gave same yields when treated under similar conditions...

  17. Fungal delignification of lignocellulosic biomass improves the saccharification of cellulosics.

    Science.gov (United States)

    Gupta, Rishi; Mehta, Girija; Khasa, Yogender Pal; Kuhad, Ramesh Chander

    2011-07-01

    The biological delignification of lignocellulosic feedstocks, Prosopis juliflora and Lantana camara was carried out with Pycnoporus cinnabarinus, a white rot fungus, at different scales under solid-state fermentation (SSF) and the fungal treated substrates were evaluated for their acid and enzymatic saccharification. The fungal fermentation at 10.0 g substrate level optimally delignified the P. juliflora by 11.89% and L. camara by 8.36%, and enriched their holocellulose content by 3.32 and 4.87%, respectively, after 15 days. The fungal delignification when scaled up from 10.0 g to 75.0, 200.0 and 500.0 g substrate level, the fungus degraded about 7.69-10.08% lignin in P. juliflora and 6.89-7.31% in L. camara, and eventually enhanced the holocellulose content by 2.90-3.97 and 4.25-4.61%, respectively. Furthermore, when the fungal fermented L. camara and P. juliflora was hydrolysed with dilute sulphuric acid, the sugar release was increased by 21.4-42.4% and the phenolics content in hydrolysate was decreased by 18.46 and 19.88%, as compared to the unfermented substrate acid hydrolysis, respectively. The reduction of phenolics in acid hydrolysates of fungal treated substrates decreased the amount of detoxifying material (activated charcoal) by 25.0-33.0% as compared to the amount required to reduce almost the same level of phenolics from unfermented substrate hydrolysates. Moreover, an increment of 21.1-25.1% sugar release was obtained when fungal treated substrates were enzymatically hydrolysed as compared to the hydrolysis of unfermented substrates. This study clearly shows that fungal delignification holds potential in utilizing plant residues for the production of sugars and biofuels.

  18. Enzyme recycling in lignocellulosic biorefineries

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Pinelo, Manuel

    2017-01-01

    platform. Cellulases are the most important enzymes required in this process, but the complex nature of lignocellulose requires several other enzymes (hemicellulases and auxiliary enzymes) for efficient hydrolysis. Enzyme recycling increases the catalytic productivity of the enzymes by reusing them...... for several batches of hydrolysis, and thereby reduces the overall cost associated with the hydrolysis. Research on this subject has been ongoing for many years and several promising technologies and methods have been developed and demonstrated. But only in a very few cases have these technologies been...... upscaled and tested in industrial settings, mainly because of many difficulties with recycling of enzymes from the complex lignocellulose hydrolyzate at industrially relevant conditions, i.e., high solids loadings. The challenges are associated with the large number of different enzymes required...

  19. An overview of key pretreatment processes for biological conversion of lignocellulosic biomass to bioethanol

    OpenAIRE

    Maurya, Devendra Prasad; Singla, Ankit; Negi, Sangeeta

    2015-01-01

    Second-generation bioethanol can be produced from various lignocellulosic biomasses such as wood, agricultural or forest residues. Lignocellulosic biomass is inexpensive, renewable and abundant source for bioethanol production. The conversion of lignocellulosic biomass to bioethanol could be a promising technology though the process has several challenges and limitations such as biomass transport and handling, and efficient pretreatment methods for total delignification of lignocellulosics. P...

  20. Comparative Proteomic Analysis of Tolerance and Adaptation of Ethanologenic Saccharomyces cerevisiae to Furfural, a Lignocellulosic Inhibitory Compound▿ †

    Science.gov (United States)

    Lin, Feng-Ming; Qiao, Bin; Yuan, Ying-Jin

    2009-01-01

    The molecular mechanism involved in tolerance and adaptation of ethanologenic Saccharomyces cerevisiae to inhibitors (such as furfural, acetic acid, and phenol) represented in lignocellulosic hydrolysate is still unclear. Here, 18O-labeling-aided shotgun comparative proteome analysis was applied to study the global protein expression profiles of S. cerevisiae under conditions of treatment of furfural compared with furfural-free fermentation profiles. Proteins involved in glucose fermentation and/or the tricarboxylic acid cycle were upregulated in cells treated with furfural compared with the control cells, while proteins involved in glycerol biosynthesis were downregulated. Differential levels of expression of alcohol dehydrogenases were observed. On the other hand, the levels of NADH, NAD+, and NADH/NAD+ were reduced whereas the levels of ATP and ADP were increased. These observations indicate that central carbon metabolism, levels of alcohol dehydrogenases, and the redox balance may be related to tolerance of ethanologenic yeast for and adaptation to furfural. Furthermore, proteins involved in stress response, including the unfolded protein response, oxidative stress, osmotic and salt stress, DNA damage and nutrient starvation, were differentially expressed, a finding that was validated by quantitative real-time reverse transcription-PCR to further confirm that the general stress responses are essential for cellular defense against furfural. These insights into the response of yeast to the presence of furfural will benefit the design and development of inhibitor-tolerant ethanologenic yeast by metabolic engineering or synthetic biology. PMID:19363068

  1. Biogas from lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Berglund Odhner, Peter; Schabbauer, Anna [Grontmij AB, Stockholm (Sweden); Sarvari Horvath, Ilona; Mohseni Kabir, Maryam [Hoegskolan i Boraas, Boraas (Sweden)

    2012-01-15

    Grontmij AB has cooperated with the University of Boraas to evaluate the technological and economical possibilities for biogas production from substrates containing lignocellulose, such as forest residues, straw and paper. The state of knowledge regarding biogas production from cellulosic biomass has been summarized. The research in the field has been described, especially focusing on pretreatment methods and their results on increased gas yields. An investigation concerning commercially available pretreatment methods and the cost of these technologies has been performed. An economic evaluation of biogas production from lignocellulosic materials has provided answers to questions regarding the profitability of these processes. Pretreatment with steam explosion was economically evaluated for three feedstocks - wood, straw and paper - and a combination of steam explosion and addition of NaOH for paper. The presented costs pertain to costs for the pretreatment step as it, in this study, was assumed that the pretreatment would be added to an existing plant and the lignocellulosic substrates would be part of a co-digestion process. The results of the investigation indicate that it is difficult to provide a positive net result when comparing the cost of pretreatment versus the gas yield (value) for two of the feedstocks - forest residues and straw. This is mainly due to the high cost of the raw material. For forest residues the steam pretreatment cost exceeded the gas yield by over 50 %, mainly due to the high cost of the raw material. For straw, the production cost was similar to the value of the gas. Paper showed the best economic result. The gas yield (value) for paper exceeded the pretreatment cost by 15 %, which makes it interesting to study paper further.

  2. Lignocellulosic Biomass Derived Functional Materials: Synthesis and Applications in Biomedical Engineering.

    Science.gov (United States)

    Zhang, Lei; Peng, Xinwen; Zhong, Linxin; Chua, Weitian; Xiang, Zhihua; Sun, Runcang

    2017-09-18

    The pertinent issue of resources shortage arising from global climate change in the recent years has accentuated the importance of materials that are environmental friendly. Despite the merits of current material like cellulose as the most abundant natural polysaccharide on earth, the incorporation of lignocellulosic biomass has the potential to value-add the recent development of cellulose-derivatives in drug delivery systems. Lignocellulosic biomass, with a hierarchical structure, comprised of cellulose, hemicellulose and lignin. As an excellent substrate that is renewable, biodegradable, biocompatible and chemically accessible for modified materials, lignocellulosic biomass sets forth a myriad of applications. To date, materials derived from lignocellulosic biomass have been extensively explored for new technological development and applications, such as biomedical, green electronics and energy products. In this review, chemical constituents of lignocellulosic biomass are first discussed before we critically examine the potential alternatives in the field of biomedical application. In addition, the pretreatment methods for extracting cellulose, hemicellulose and lignin from lignocellulosic biomass as well as their biological applications including drug delivery, biosensor, tissue engineering etc will be reviewed. It is anticipated there will be an increasing interest and research findings in cellulose, hemicellulose and lignin from natural resources, which help provide important directions for the development in biomedical applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Destroying lignocellulosic matters for enhancing methane production from excess sludge.

    Science.gov (United States)

    Hao, Xiaodi; Hu, Yuansheng; Cao, Daqi

    2016-01-01

    A lot of lignocellulosic matters are usually present in excess sludge, which are hardly degraded in anaerobic digestion (AD) and thus remains mostly in digested sludge. This is a reason why the conversion rate of sludge organics into energy (CH4) is often low. Obviously, the hydrolysis of AD cannot destruct the structure of lignocellulosic matters. Structural destruction of lignocellulosic matters has to be performed in AD. In this study, pretreatments with the same principles as cell disintegration of sludge were applied to destruct lignocellulosic matters so that these materials could be converted to CH4 via AD. Acid, alkali, thermal treatment and ultrasonic were used in the experiments to observe the destructed/degraded efficiency of lignocellulosic matters. Thermal treatment was found to be the most effective pretreatment. Under optimized conditions (T = 150 °C and t = 30  min), pretreated sludge had a degraded rate of 52.6% in AD, due to easy destruction and/or degradation of hemicelluloses and celluloses in pretreatment. The sludge pretreated by thermal treatment could enhance the CH4 yield (mL CH4 g(-1) VSS) by 53.6% compared to raw sludge. Economically, the thermal treatment can balance the input energy with the produced energy (steam and electricity).

  4. Rational design and evolutional fine tuning of Saccharomyces cerevisiae for biomass breakdown.

    Science.gov (United States)

    Hasunuma, Tomohisa; Ishii, Jun; Kondo, Akihiko

    2015-12-01

    Conferring biomass hydrolysis activity on yeast through genetic engineering has paved the way for the development of groundbreaking processes for producing liquid fuels and commodity chemicals from lignocellulosic biomass. However, the overproduction and misfolding of heterologous and endogenous proteins can trigger cellular stress, increasing the metabolic burden and retarding growth. Improving the efficiency of lignocellulosic breakdown requires engineering of yeast secretory pathway based on system-wide metabolic analysis as well as DNA constructs for enhanced cellulase gene expression with advanced molecular biology tools. Also, yeast is subjected to severe stress due to toxic compounds generated during lignocellulose pretreatment in consolidated saccharification and fermentation processes. The prospect for development of robust yeast strains makes combining evolutionary and rational engineering strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Methods for treating lignocellulosic materials

    Science.gov (United States)

    Jansen, Robert; Travisano, Philip; Madsen, Lee; Matis, Neta; Lawson, James Alan; Lapidot, Noa; Eyal, Aharon M.; Bauer, Timothy Allen; Belman, Ziv-Vladimir; Hallac, Bassem; Zviely, Michael

    2017-10-10

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  6. Methods for treating lignocellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Robert; Gregoire, Claire; Travisano, Philip; Madsen, Lee; Matis, Neta; Har-Tal, Yael Miriam; Eliahu, Shay; Lawson, James Alan; Lapidot, Noa; Eyal, Aharon M.; Bauer, Timothy Allen; McWilliams, Paul; Zviely, Michael; Carden, Adam

    2017-05-16

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  7. Methods for treating lignocellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Robert; Gregoire, Claire; Travisano, Philip; Madsen, Lee; Matis, Neta; Har-Tal, Yael Miriam; Eliahu, Shay; Lawson, James Alan; Lapidot, Noa; Burke, Luke; Eyal, Aharon M.; Bauer, Timothy Allen; Sade, Hagit; McWilliams, Paul; Zviely, Michael; Carden, Adam

    2017-04-25

    The present invention relates to methods of processing lignocellulosic material to obtain hemicellulose sugars, cellulose sugars, lignin, cellulose and other high-value products. Also provided are hemicellulose sugars, cellulose sugars, lignin, cellulose, and other high-value products.

  8. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Directory of Open Access Journals (Sweden)

    H. V. Lee

    2014-01-01

    Full Text Available Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

  9. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Science.gov (United States)

    Lee, H. V.; Hamid, S. B. A.; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein. PMID:25247208

  10. Bioethanol Production from Sugarcane Bagasse by a Novel Brazilian Pentose Fermenting Yeast Scheffersomyces shehatae UFMG-HM 52.2: Evaluation of Fermentation Medium

    Directory of Open Access Journals (Sweden)

    F. A. F. Antunes

    2014-01-01

    Full Text Available Bioconversion of hemicellulosic sugars into second generation (2G ethanol plays a pivotal role in the overall success of biorefineries. In this study, ethanol production performance of a novel xylose-fermenting yeast, Scheffersomyces shehatae UFMG-HM 52.2, was evaluated under batch fermentation conditions using sugarcane bagasse (SB hemicellulosic hydrolysate as carbon source. Dilute acid hydrolysis of SB was performed to obtain sugarcane bagasse hemicellulosic hydrolysate (SBHH. It was concentrated, detoxified, and supplemented with nutrients in different formulations to prepare the fermentation medium to the yeast evaluation performance. S. shehatae UFMG-HM 52.2 (isolated from Brazilian Atlantic rain forest ecosystem was used in fermentations carried out in Erlenmeyer flasks maintained in a rotator shaker at 30°C and 200 rpm for 72 h. The use of a fermentation medium composed of SBHH supplemented with 5 g/L ammonium sulfate, 3 g/L yeast extract, and 3 g/L malt extract resulted in 0.38 g/g of ethanol yield and 0.19 g L.h of volumetric productivity after 48 h of incubation time.

  11. Catalytic Gasification of Lignocellulosic Biomass

    NARCIS (Netherlands)

    Chodimella, Pramod; Seshan, Kulathuiyer; Schlaf, Marcel; Zhang, Z. Conrad

    2015-01-01

    Gasification of lignocellulosic biomass has attracted substantial current research interest. Various possible routes to convert biomass to fuels have been explored. In the present chapter, an overview of the gasification processes and their possible products are discussed. Gasification of solid

  12. Bioconversion of lignocellulosic biomass to xylitol: An overview.

    Science.gov (United States)

    Venkateswar Rao, Linga; Goli, Jyosthna Khanna; Gentela, Jahnavi; Koti, Sravanthi

    2016-08-01

    Lignocellulosic wastes include agricultural and forest residues which are most promising alternative energy sources and serve as potential low cost raw materials that can be exploited to produce xylitol. The strong physical and chemical construction of lignocelluloses is a major constraint for the recovery of xylose. The large scale production of xylitol is attained by nickel catalyzed chemical process that is based on xylose hydrogenation, that requires purified xylose as raw substrate and the process requires high temperature and pressure that remains to be cost intensive and energy consuming. Therefore, there is a necessity to develop an integrated process for biotechnological conversion of lignocelluloses to xylitol and make the process economical. The present review confers about the pretreatment strategies that facilitate cellulose and hemicellulose acquiescent for hydrolysis. There is also an emphasis on various detoxification and fermentation methodologies including genetic engineering strategies for the efficient conversion of xylose to xylitol. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biogeochemical cycling of lignocellulosic carbon in marine and freshwater ecosystems: relative contributions of procaryotes and eucaryotes

    International Nuclear Information System (INIS)

    Benner, R.; Moran, M.A.; Hodson, R.E.

    1986-01-01

    The relative contributions of procaryotes and eucaryotes to the degradation of the lignin and polysaccharide components of lignocellulosic detritus in two marine and two freshwater wetland ecosystems were determined. Two independent methods - physical separation of bacteria from fungi and other eucaryotes by size fractionation, and antibiotic treatments - were used to estimate procaryotic and eucaryotic contributions to the degradation of [ 14 C-lignin]lignocelluloses and [ 13 C-polysaccharide]lignocelluloses in samples of water and decaying plant material from each environment. Both methods yielded similar results; bacteria were the predominant degraders of lignocellulose in each of the aquatic ecosystems. These results indicate a basic difference between the microbial degradation of lignocellulosic material in terrestrial and aquatic environments. Fungi have long been considered the predominant degraders of lignocellulose in terrestrial systems; our results indicate that in aquatic systems bacteria are the predominant degraders of lignocellulose

  14. LIGNOCELLULOSIC BIOMASS AFTER EXPLOSIVE AUTOHYDROLYSIS AS SUBSTRATE TO BUTANOL OBTAINING

    Directory of Open Access Journals (Sweden)

    Tigunova

    2016-08-01

    Full Text Available The aim of the work was investigation of the effect of the explosive autohydrolysis on lignocellulosic biomass (saving, switchgrass biomass for consequent use as a substrate to produce biofuels such as butanol. Butanol-producing strains, switchgrass Panicum virgatum L. biomass and its components after autohydrolysis were used in study. The thermobaric pressure pretreatment of lignocellulosic biomass was carried out using specially designed equipment. The effect of explosive autohydrolysis on lignocellulosic biomass for further use in producing biofuels using microbial conversion was studied. Components of lignocellulosic biomass were fractionated after undergoing thermobaric treatment. The possibility of using different raw material components after using explosive autohydrolysis processing to produce biobutanol was found. Products of switchgrass biomass autohydrolysis were shown to need further purification before fermentation from furfural formed by thermobaric pretreatment and inhibiting the growth of microorganisms. The ability of strains of the genus Clostridium to use cellulose as a substrate for fermentation was proved. It was found that using explosive autohydrolysis pretreatment to savings allowed boosting the butanol accumulation by 2 times.

  15. Biological strategies for enhanced hydrolysis of lignocellulosic biomass during anaerobic digestion: Current status and future perspectives.

    Science.gov (United States)

    Shrestha, Shilva; Fonoll, Xavier; Khanal, Samir Kumar; Raskin, Lutgarde

    2017-12-01

    Lignocellulosic biomass is the most abundant renewable bioresource on earth. In lignocellulosic biomass, the cellulose and hemicellulose are bound with lignin and other molecules to form a complex structure not easily accessible to microbial degradation. Anaerobic digestion (AD) of lignocellulosic biomass with a focus on improving hydrolysis, the rate limiting step in AD of lignocellulosic feedstocks, has received considerable attention. This review highlights challenges with AD of lignocellulosic biomass, factors contributing to its recalcitrance, and natural microbial ecosystems, such as the gastrointestinal tracts of herbivorous animals, capable of performing hydrolysis efficiently. Biological strategies that have been evaluated to enhance hydrolysis of lignocellulosic biomass include biological pretreatment, co-digestion, and inoculum selection. Strategies to further improve these approaches along with future research directions are outlined with a focus on linking studies of microbial communities involved in hydrolysis of lignocellulosics to process engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Consolidated Bio-Processing of Cellulosic Biomass for Efficient Biofuel Production Using Yeast Consortium

    Science.gov (United States)

    Goyal, Garima

    Fossil fuels have been the major source for liquid transportation fuels for ages. However, decline in oil reserves and environmental concerns have raised a lot of interest in alternative and renewable energy sources. One promising alternative is the conversion of plant biomass into ethanol. The primary biomass feed stocks currently being used for the ethanol industry have been food based biomass (corn and sugar cane). However, interest has recently shifted to replace these traditional feed-stocks with more abundant, non-food based cellulosic biomass such as agriculture wastes (corn stover) or crops (switch grass). The use of cellulosic biomass as feed stock for the production of ethanol via bio-chemical routes presents many technical challenges not faced with the use of corn or sugar-cane as feed-stock. Recently, a new process called consolidated Bio-processing (CBP) has been proposed. This process combines simultaneous saccharification of lignocellulose with fermentation of the resulting sugars into a single process step mediated by a single microorganism or microbial consortium. Although there is no natural microorganism that possesses all properties of lignocellulose utilization and ethanol production desired for CBP, some bacteria and fungi exhibit some of the essential traits. The yeast Saccharomyces cerevisiae is the most attractive host organism for the usage of this strategy due to its high ethanol productivity at close to theoretical yields (0.51g ethanol/g glucose consumed), high osmo- and ethanol- tolerance, natural robustness in industrial processes, and ease of genetic manipulation. Introduction of the cellulosome, found naturally in microorganisms, has shown new directions to deal with recalcitrant biomass. In this case enzymes work in synergy in order to hydrolyze biomass more effectively than in case of free enzymes. A microbial consortium has been successfully developed, which ensures the functional assembly of minicellulosome on the yeast surface

  17. Cooking with Active Oxygen and Solid Alkali: A Promising Alternative Approach for Lignocellulosic Biorefineries.

    Science.gov (United States)

    Jiang, Yetao; Zeng, Xianhai; Luque, Rafael; Tang, Xing; Sun, Yong; Lei, Tingzhou; Liu, Shijie; Lin, Lu

    2017-10-23

    Lignocellulosic biomass, a matrix of biopolymers including cellulose, hemicellulose, and lignin, has gathered increasing attention in recent years for the production of chemicals, fuels, and materials through biorefinery processes owing to its renewability and availability. The fractionation of lignocellulose is considered to be the fundamental step to establish an economical and sustainable lignocellulosic biorefinery. In this Minireview, we summarize a newly developed oxygen delignification for lignocellulose fractionation called cooking with active oxygen and solid alkali (CAOSA), which can fractionate lignocellulose into its constituents and maintain its processable form. In the CAOSA approach, environmentally friendly chemicals are applied instead of undesirable chemicals such as strong alkalis and sulfides. Notably, the alkali recovery for this process promises to be relatively simple and does not require causticizing or sintering. These features make the CAOSA process an alternative for both lignocellulose fractionation and biomass pretreatment. The advantages and challenges of CAOSA are also discussed to provide a comprehensive perspective with respect to existing strategies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Low temperature lignocellulose pretreatment: effects and interactions of pretreatment pH are critical for maximizing enzymatic monosaccharide yields from wheat straw

    DEFF Research Database (Denmark)

    Pedersen, Mads; Johansen, Katja S.; Meyer, Anne S.

    2011-01-01

    Background: The recent development of improved enzymes and pentose-using yeast for cellulosic ethanol processes calls for new attention to the lignocellulose pretreatment step. This study assessed the influence of pretreatment pH, temperature, and time, and their interactions on the enzymatic...... alkaline pretreatments. Alkaline pretreatments also solubilized most of the lignin. Conclusions: Pretreatment pH exerted significant effects and factor interactions on the enzymatic glucose and xylose releases. Quite extreme pH values were necessary with mild thermal pretreatment strategies (T...... glucose and xylose yields from mildly pretreated wheat straw in multivariate experimental designs of acid and alkaline pretreatments. Results: The pretreatment pH was the most significant factor affecting both the enzymatic glucose and xylose yields after mild thermal pretreatments at maximum 140 degrees...

  19. Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

    Science.gov (United States)

    ZJ Wang; TQ Lan; JY Zhu

    2013-01-01

    Nonspecific (nonproductive) binding (adsorption) of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) is a relatively new process, but demonstrated robust performance for sugar and biofuel...

  20. Identification of candidate genes for yeast engineering to improve bioethanol production in very high gravity and lignocellulosic biomass industrial fermentations

    Directory of Open Access Journals (Sweden)

    Pereira Francisco B

    2011-12-01

    Full Text Available Abstract Background The optimization of industrial bioethanol production will depend on the rational design and manipulation of industrial strains to improve their robustness against the many stress factors affecting their performance during very high gravity (VHG or lignocellulosic fermentations. In this study, a set of Saccharomyces cerevisiae genes found, through genome-wide screenings, to confer resistance to the simultaneous presence of different relevant stresses were identified as required for maximal fermentation performance under industrial conditions. Results Chemogenomics data were used to identify eight genes whose expression confers simultaneous resistance to high concentrations of glucose, acetic acid and ethanol, chemical stresses relevant for VHG fermentations; and eleven genes conferring simultaneous resistance to stresses relevant during lignocellulosic fermentations. These eleven genes were identified based on two different sets: one with five genes granting simultaneous resistance to ethanol, acetic acid and furfural, and the other with six genes providing simultaneous resistance to ethanol, acetic acid and vanillin. The expression of Bud31 and Hpr1 was found to lead to the increase of both ethanol yield and fermentation rate, while Pho85, Vrp1 and Ygl024w expression is required for maximal ethanol production in VHG fermentations. Five genes, Erg2, Prs3, Rav1, Rpb4 and Vma8, were found to contribute to the maintenance of cell viability in wheat straw hydrolysate and/or the maximal fermentation rate of this substrate. Conclusions The identified genes stand as preferential targets for genetic engineering manipulation in order to generate more robust industrial strains, able to cope with the most significant fermentation stresses and, thus, to increase ethanol production rate and final ethanol titers.

  1. Expression of Genes Related to Oxidative Stress in Yeast Treated with Ionizing Radiation and N-acetyl -L-cysteine

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Young; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2010-10-15

    Ionizing radiation (IR) induces water radiolysis, which generates highly reactive hydroxyl radicals. Reactive oxygen species (ROS) cause apoptosis and cell damage including DNA strand breaks (DSBs), base damage, protein damage and lipid-hydroperoxide. Detoxifying enzymes are immediately triggered for ROS scavenging. Yeast contains two forms of superoxide dismutase (SOD). SOD1 as a cytosolic copper-zinc superoxide dismutase is located in the cytoplasm and cytosol. SOD2 as a manganese containing enzyme is act in mitochondria matrix and mitochondrion. These enzymes scavenge superoxide radicals by catalyzing the conversion of two of these radicals into hydrogen peroxide and molecular oxygen. The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen. Yeast contains two catalases. Catalase A (CTA1) and Cytosolic catalase T (CTT1) is located in peroxisome and cytoplasm, respectively. Yeast has two glutathione (GSH) peroxidases, which are GPX1 and GPX2. GPX1 and GPX2 are component of cellular component and cytoplasm, respectively. The biochemical function of GSH peroxidase is to reduce lipid-hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. Otherwise, chemicals and materials help ROS detoxification against oxidative damage. N-acetyl-Lcysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. In this study, we examined the effect of NAC through gene expressions related to protective enzyme against oxidative stress in yeast

  2. Expression of Genes Related to Oxidative Stress in Yeast Treated with Ionizing Radiation and N-acetyl -L-cysteine

    International Nuclear Information System (INIS)

    Park, Ji Young; Kim, Jin Kyu; Nili, Mohammad

    2010-01-01

    Ionizing radiation (IR) induces water radiolysis, which generates highly reactive hydroxyl radicals. Reactive oxygen species (ROS) cause apoptosis and cell damage including DNA strand breaks (DSBs), base damage, protein damage and lipid-hydroperoxide. Detoxifying enzymes are immediately triggered for ROS scavenging. Yeast contains two forms of superoxide dismutase (SOD). SOD1 as a cytosolic copper-zinc superoxide dismutase is located in the cytoplasm and cytosol. SOD2 as a manganese containing enzyme is act in mitochondria matrix and mitochondrion. These enzymes scavenge superoxide radicals by catalyzing the conversion of two of these radicals into hydrogen peroxide and molecular oxygen. The hydrogen peroxide formed by superoxide dismutase and by other processes is scavenged by catalase, a ubiquitous heme protein that catalyzes the dismutation of hydrogen peroxide into water and molecular oxygen. Yeast contains two catalases. Catalase A (CTA1) and Cytosolic catalase T (CTT1) is located in peroxisome and cytoplasm, respectively. Yeast has two glutathione (GSH) peroxidases, which are GPX1 and GPX2. GPX1 and GPX2 are component of cellular component and cytoplasm, respectively. The biochemical function of GSH peroxidase is to reduce lipid-hydroperoxides to their corresponding alcohols and to reduce free hydrogen peroxide to water. Otherwise, chemicals and materials help ROS detoxification against oxidative damage. N-acetyl-Lcysteine (NAC) having a thiol, a precursor for glutathione (GSH), is known as one of the antioxidants. In this study, we examined the effect of NAC through gene expressions related to protective enzyme against oxidative stress in yeast

  3. Anaerobic biodegradation of the lignin and polysaccharide components of lignocellulose and synthetic lignin by sediment microflora

    Energy Technology Data Exchange (ETDEWEB)

    Benner, R.; Maccubbin, A.E.; Hodson, R.E.

    1984-05-01

    Specifically radiolabeled (/sup 14/C-lignin)lignocelluloses and (/sup 14/C-polysaccharide)lignocelluloses were prepared from a variety of marine and freshwater wetland plants including a grass, a sedge, a rush, and a hardwood. These (/sup 14/C)lignocellulose preparations and synthetic (/sup 14/C)lignin were incubated anaerobically with anoxic sediments collected from a salt marsh, a freshwater marsh, and a mangrove swamp. During long-term incubations lasting up to 300 days, the lignin and polysaccharide components of the lignocelluloses were slowly degraded anaerobically to /sup 14/CO/sub 2/ and /sup 14/CH/sub 4/. Lignocelluloses derived from herbaceous plants were degraded more rapidly than lignocellulose derived from the hardwood. After 294 days, 16.9% of the lignin component and 30.0% of the polysaccharide component of lignocellulose derived from the grass used (Spartina alterniflora) were degraded to gaseous end products. In contrast, after 246 days, only 1.5% of the lignin component and 4.1% of the polysaccharide component of lignocellulose derived from the hardwood used (Rhizophora mangle) were degraded to gaseous end products. Synthetic (/sup 14/C) lignin was degraded anaerobically faster than the lignin component of the hardwood lignocellulose; after 276 days 3.7% of the synthetic lignin was degraded to gaseous end products. Contrary to previous reports, these results demonstrate that lignin and lignified plant tissues are biodegradable in the absence of oxygen. Although lignocelluloses are recalcitrant to anaerobic biodegradation, rates of degradation measured in aquatic sediments are significant and have important implications for the biospheric cycling of carbon from these abundant biopolymers. 31 references.

  4. Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    McAloon, A.; Taylor, F.; Yee, W.; Ibsen, K.; Wooley, R.

    2000-10-25

    The mature corn-to-ethanol industry has many similarities to the emerging lignocellulose-to-ethanol industry. It is certainly possible that some of the early practitioners of this new technology will be the current corn ethanol producers. In order to begin to explore synergies between the two industries, a joint project between two agencies responsible for aiding these technologies in the Federal government was established. This joint project of the USDA-ARS and DOE/NREL looked at the two processes on a similar process design and engineering basis, and will eventually explore ways to combine them. This report describes the comparison of the processes, each producing 25 million annual gallons of fuel ethanol. This paper attempts to compare the two processes as mature technologies, which requires assuming that the technology improvements needed to make the lignocellulosic process commercializable are achieved, and enough plants have been built to make the design well-understood. Ass umptions about yield and design improvements possible from continued research were made for the emerging lignocellulose process. In order to compare the lignocellulose-to-ethanol process costs with the commercial corn-to-ethanol costs, it was assumed that the lignocellulose plant was an Nth generation plant, built after the industry had been sufficiently established to eliminate first-of-a-kind costs. This places the lignocellulose plant costs on a similar level with the current, established corn ethanol industry, whose costs are well known. The resulting costs of producing 25 million annual gallons of fuel ethanol from each process were determined. The figure below shows the production cost breakdown for each process. The largest cost contributor in the corn starch process is the feedstock; for the lignocellulosic process it is the capital cost, which is represented by depreciation cost on an annual basis.

  5. Dry fractionation process as an important step in current and future lignocellulose biorefineries: a review.

    Science.gov (United States)

    Barakat, Abdellatif; de Vries, Hugo; Rouau, Xavier

    2013-04-01

    The use of lignocellulosic biomass is promising for biofuels and materials and new technologies for the conversion need to be developed. However, the inherent properties of native lignocellulosic materials make them resistant to enzymatic and chemical degradation. Lignocellulosic biomass requires being pretreated to change the physical and chemical properties of lignocellulosic matrix in order to increase cell wall polymers accessibility and bioavailability. Mechanical size reduction may be chemical free intensive operation thanks to decreasing particles size and cellulose crystallinity, and increasing accessible surface area. Changes in these parameters improve the digestibility and the bioconversion of lignocellulosic biomass. However, mechanical size reduction requires cost-effective approaches from an energy input point of view. Therefore, the energy consumption in relation to physicochemical properties of lignocellulosic biomass was discussed. Even more, chemical treatments combined with physicochemical size reduction approaches are proposed to reduce energy consumption in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Improved process for producing a fermentation product from a lignocellulose-containing material

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention relates to the production of hydrolyzates from a lignocellulose-containing material, and to fermentation of the hydrolyzates. More specifically, the present invention relates to the detoxification of phenolic inhibitors and toxins formed during the processing of lignocellulose...

  7. A process for producing a fermentation product from a lignocellulose-containing material

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to the production of hydrolyzates from a lignocellulose-containing material, and to fermentation of the hydrolyzates. More specifically, the present invention relates to the detoxification of phenolic inhibitors and toxins formed during the processing of lignocellulose...

  8. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    Science.gov (United States)

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  9. Effects of gamma irradiation on the decomposition and biodegradability of lignocellulose

    International Nuclear Information System (INIS)

    Gas, G.; Bono, J.J.; Boudet, A.M.; Jaureguy, L.; Torres, L.; Mathieu, J.

    1984-01-01

    The study of effects of a pretreatment by gamma radiation on radioactive lignocellulose from poplar-tree and on subsequent biodegradation by fungi is realized for residues and soluble products. Measurement before and after treatment, of cellulose accessibility to an exogen cellulase shows the interest of irradiation in transformation processes of lignocellulosic products [fr

  10. A fundamental review of the relationships between nanotechnology and lignocellulosic biomass

    Science.gov (United States)

    Theodore Wegner; E. Philip Jones

    2009-01-01

    At first glance, the relationship between nanotechnology and lignocellulosic biomass may seem to be unconnected or at best tenuously connected. It is important to recognize that. at a fundamental level, lignocellulosic biomass is made up of nanometer-size constitutive building block units that provide valuable properties to wood and other types of renewable...

  11. High glucose recovery from direct enzymatic hydrolysis of bisulfite-pretreatment on non-detoxified furfural residues.

    Science.gov (United States)

    Xing, Yang; Bu, Lingxi; Sun, Dafeng; Liu, Zhiping; Liu, Shijie; Jiang, Jianxin

    2015-10-01

    This study reports four schemes to pretreat wet furfural residues (FRs) with sodium bisulfite for production of fermentable sugar. The results showed that non-detoxified FRs (pH 2-3) had great potential to lower the cost of bioconversion. The optimal process was that unwashed FRs were first pretreated with bisulfite, and the whole slurry was then directly used for enzymatic hydrolysis. A maximum glucose yield of 99.4% was achieved from substrates pretreated with 0.1 g NaHSO3/g dry substrate (DS), at a relatively low temperature of 100 °C for 3 h. Compared with raw material, enzymatic hydrolysis at a high-solid of 16.5% (w/w) specifically showed more excellent performance with bisulfite treated FRs. Direct bisulfite pretreatment improved the accessibility of substrates and the total glucose recovery. Lignosulfonate in the non-detoxified slurry decreased the non-productive adsorption of cellulase on the substrate, thus improving enzymatic hydrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Lignin pyrolysis for profitable lignocellulosic biorefineries

    NARCIS (Netherlands)

    Wild, de P.J.; Gosselink, R.J.A.; Huijgen, W.J.J.

    2014-01-01

    Bio-based industries (pulp and paper and biorefineries) produce > 50 Mt/yr of lignin that results from fractionation of lignocellulosic biomass. Lignin is world's second biopolymer and a major potential source for production of performance materials and aromatic chemicals. Lignin valorization is

  13. Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

    Directory of Open Access Journals (Sweden)

    Keikhosro Karimi

    2008-09-01

    Full Text Available Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pretreatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. The present work is dedicated to reviewing the methods that have been studied for pretreatment of lignocellulosic wastes for conversion to ethanol or biogas. Effective parameters in pretreatment of lignocelluloses, such as crystallinity, accessible surface area, and protection by lignin and hemicellulose are described first. Then, several pretreatment methods are discussed and their effects on improvement in ethanol and/or biogas production are described. They include milling, irradiation, microwave, steam explosion, ammonia fiber explosion (AFEX, supercritical CO2 and its explosion, alkaline hydrolysis, liquid hot-water pretreatment, organosolv processes, wet oxidation, ozonolysis, dilute- and concentrated-acid hydrolyses, and biological pretreatments.

  14. Biodegradation of Lignocelluloses in Sewage Sludge Composting and Vermicomposting

    Directory of Open Access Journals (Sweden)

    Hosein Alidadi

    2012-08-01

    Full Text Available Please cite this article as: Alidadi H, Najafpour AA, Vafaee A, Parvaresh A, Peiravi R. Biodegradation of lignocelluloses in sewage sludge composting and vermicomposting. Arch Hyg Sci 2012;1(1:1-5.   Aims of the Study: The aim of this study was to determine the amount of lignin degradation and biodegradation of organic matter and change of biomass under compost and vermicomposting of sewage sludge. Materials & Methods: Sawdust was added to sewage sludge at 1:3 weight bases to Carbon to Nitrogen ratio of 25:1 for composting or vermicomposting. Lignin and volatile solids were determined at different periods, of 0, 10, 30, 40 and 60 days of composting or vermicomposting period to determine the biodegradation of lignocellulose to lignin. Results were expressed as mean of two replicates and the comparisons among means were made using the least significant difference test calculated (p <0.05. Results: After 60 days of experiment period, the initial lignin increased from 3.46% to 4.48% for compost and 3.46% to 5.27% for vermicompost. Biodegradation of lignocellulose was very slow in compost and vermicompost processes. Vermicomposting is a much faster process than compost to convert lignocellulose to lignin (p <0.05. Conclusions: The organic matter losses in sewage sludge composting and vermicomposting are due to the degradation of the lignin fractions. By increasing compost age, the amount of volatile solids will decrease.

  15. Laccases as a Potential Tool for the Efficient Conversion of Lignocellulosic Biomass: A Review

    Directory of Open Access Journals (Sweden)

    Úrsula Fillat

    2017-05-01

    Full Text Available The continuous increase in the world energy and chemicals demand requires the development of sustainable alternatives to non-renewable sources of energy. Biomass facilities and biorefineries represent interesting options to gradually replace the present industry based on fossil fuels. Lignocellulose is the most promising feedstock to be used in biorefineries. From a sugar platform perspective, a wide range of fuels and chemicals can be obtained via microbial fermentation processes, being ethanol the most significant lignocellulose-derived fuel. Before fermentation, lignocellulose must be pretreated to overcome its inherent recalcitrant structure and obtain the fermentable sugars. Usually, harsh conditions are required for pretreatment of lignocellulose, producing biomass degradation and releasing different compounds that are inhibitors of the hydrolytic enzymes and fermenting microorganisms. Moreover, the lignin polymer that remains in pretreated materials also affects biomass conversion by limiting the enzymatic hydrolysis. The use of laccases has been considered as a very powerful tool for delignification and detoxification of pretreated lignocellulosic materials, boosting subsequent saccharification and fermentation processes. This review compiles the latest studies about the application of laccases as useful and environmentally friendly delignification and detoxification technology, highlighting the main challenges and possible ways to make possible the integration of these enzymes in future lignocellulose-based industries.

  16. Decomposition of [14C]lignocelluloses of Spartina alterniflora and a comparison with field experiments

    International Nuclear Information System (INIS)

    Wilson, J.O.

    1985-01-01

    Decomposition of lignocelluloses from Spartina alterniflora in salt-marsh sediments was measured by using 14 C-labeled compounds. Rates of decomposition were fastest in the first 4 days of incubation and declined later. Lignins labeled in side chains were mineralized slightly faster than uniformly labeled lignins; 12% of the [side chain- 14 C]lignin-labeled lignocellulose was mineralized after 816 h of incubation, whereas only 8% of the [U- 14 C]lignin-labeled lignocelluloses were degraded during this period. The carbohydrate moiety within the lignocellulose complex was degraded about four times faster than the lignin moiety; after 816 h of incubation, 29 to 37% of the carbohydrate moiety had been mineralized. Changes in concentration of lignin and cellulose in litter of S. alterniflora were followed over 2 years of decay. Cellulose disappeared from litter more rapidly than lignin; 50% of the initial content of cellulose was lost after 130 days, whereas lignin required 330 to 380 days for 50% loss. The slow loss of lignin compared with other litter components resulted in a progressive enrichment of litter in lignin content. The rates of mineralization of [ 14 C]lignocelluloses in marsh sediments were similar to the rates of lignocellulose decomposition in litter on the marsh

  17. INHIBITION OF THE GROWTH OF TOLERANT YEAST Saccharomyces cerevisiae STRAIN I136 BY A MIXTURE OF SYNTHETIC INHIBITORS

    Directory of Open Access Journals (Sweden)

    Eny Ida Riyanti

    2017-09-01

    Full Text Available Biomass from lignocellulosic wastes is a potential source for biobased products.  However, one of the constraints in utilization of biomass hydrolysate is the presence of inhibitors. Therefore, the use of inhibitor-tolerant microorganisms in the fermentation is required. The study aimed to investigate the effect of a mixture of inhibitors on the growth of Saccharomyces cerevisiae strain I136 grown in medium containing synthetic inhibitors (acetic acid, formic acid, furfural, 5-hydroxymethyl furfural/5-HMF, and levulinic acid in four different concentrations with a mixture of carbon sources, glucose  (50 g.l-1 and xylose (50 g.l-1 at 30oC. The parameters related to growth and fermentation products were observed. Results showed that the strain was able to grow in media containing natural inhibitors (BSL medium with µmax of 0.020/h. Higher level of synthetic inhibitors prolonged the lag phase, decreased the cell biomass and ethanol production, and specific growth rate. The strain could detoxify furfural and 5-HMF and produced the highest ethanol (Y(p/s of 0.32 g.g-1 when grown in BSL. Glucose was utilized as its level decreased in a result of increase in cell biomass, in contrast to xylose which was not consumed. The highest cell biomass was produced in YNB with Y (x/s value of 0.25 g.g-1. The strain produced acetic acid as a dominant side product and could convert furfural into a less toxic compound, hydroxyl furfural. This robust tolerant strain provides basic information on resistance mechanism and would be useful for bio-based cell factory using lignocellulosic materials. 

  18. Improved bioethanol production using fusants of Saccharomyces cerevisiae and xylose-fermenting yeasts.

    Science.gov (United States)

    Kumari, Rajni; Pramanik, K

    2012-06-01

    The present research deals with the development of a hybrid yeast strain with the aim of converting pentose and hexose sugar components of lignocellulosic substrate to bioethanol by fermentation. Different fusant strains were obtained by fusing protoplasts of Saccharomyces cerevisiae and xylose-fermenting yeasts such as Pachysolen tannophilus, Candida shehatae and Pichia stipitis. The fusants were sorted by fluorescent-activated cell sorter and further confirmed by molecular characterization. The fusants were evaluated by fermentation of glucose-xylose mixture and the highest ethanol producing fusant was used for further study to ferment hydrolysates produced by acid pretreatment and enzymatic hydrolysis of cotton gin waste. Among the various fusant and parental strains used under present study, RPR39 was found to be stable and most efficient strain giving maximum ethanol concentration (76.8 ± 0.31 g L(-1)), ethanol productivity (1.06 g L(-1) h(-1)) and ethanol yield (0.458 g g(-1)) by fermentation of glucose-xylose mixture under test conditions. The fusant has also shown encouraging result in fermenting hydrolysates of cotton gin waste with ethanol concentration of 7.08 ± 0.142 g L(-1), ethanol yield of 0.44 g g(-1), productivity of 0.45 g L(-1) h(-1) and biomass yield of 0.40 g g(-1).

  19. Biological processes for advancing lignocellulosic waste biorefinery by advocating circular economy.

    Science.gov (United States)

    Liguori, Rossana; Faraco, Vincenza

    2016-09-01

    The actualization of a circular economy through the use of lignocellulosic wastes as renewable resources can lead to reduce the dependence from fossil-based resources and contribute to a sustainable waste management. The integrated biorefineries, exploiting the overall lignocellulosic waste components to generate fuels, chemicals and energy, are the pillar of the circular economy. The biological treatment is receiving great attention for the biorefinery development since it is considered an eco-friendly alternative to the physico-chemical strategies to increase the biobased product recovery from wastes and improve saccharification and fermentation yields. This paper reviews the last advances in the biological treatments aimed at upgrading lignocellulosic wastes, implementing the biorefinery concept and advocating circular economy. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The application of biotechnology on the enhancing of biogas production from lignocellulosic waste.

    Science.gov (United States)

    Wei, Suzhen

    2016-12-01

    Anaerobic digestion of lignocellulosic waste is considered to be an efficient way to answer present-day energy crisis and environmental challenges. However, the recalcitrance of lignocellulosic material forms a major obstacle for obtaining maximum biogas production. The use of biological pretreatment and bioaugmentation for enhancing the performance of anaerobic digestion is quite recent and still needs to be investigated. This paper reviews the status and perspectives of recent studies on biotechnology concept and investigates its possible use for enhancing biogas production from lignocellulosic waste with main emphases on biological pretreatment and bioaugmentation techniques.

  1. Solar assisted alkali pretreatment of garden biomass: Effects on lignocellulose degradation, enzymatic hydrolysis, crystallinity and ultra-structural changes in lignocellulose

    International Nuclear Information System (INIS)

    Gabhane, Jagdish; William, S.P.M. Prince; Vaidya, Atul N.; Das, Sera; Wate, Satish R.

    2015-01-01

    Highlights: • SAAP is an efficient and economic means of pretreatment. • SAAP was found to be efficient in lignin and hemicellulose removal. • SAAP enhanced the enzymatic hydrolysis. • FTIR, XRD and SEM provided vivid understanding about the mode of action of SAAP. • Mass balance closer of 98% for pretreated GB confirmed the reliability of SAAP. - Abstract: A comprehensive study was carried out to assess the effectiveness of solar assisted alkali pretreatment (SAAP) on garden biomass (GB). The pretreatment efficiency was assessed based on lignocellulose degradation, conversion of cellulose into reducing sugars, changes in the ultra-structure and functional groups of lignocellulose and impact on the crystallinity of cellulose, etc. SAAP was found to be efficient for the removal of lignin and hemicellulose that facilitated enzymatic hydrolysis of cellulose. FTIR and XRD studies provided details on the effectiveness of SAAP on lignocellulosic moiety and crystallinity of cellulose. Scanning electron microscopic analysis showed ultra-structural disturbances in the microfibrils of GB as a result of pretreatment. The mass balance closer of 97.87% after pretreatment confirmed the reliability of SAAP pretreatment. Based on the results, it is concluded that SAAP is not only an efficient means of pretreatment but also economical as it involved no energy expenditure for heat generation during pretreatment

  2. Effects of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses

    Science.gov (United States)

    X.L. Luo; Junyong Zhu; Roland Gleisner; H.Y. Zhan

    2011-01-01

    This article reports the effect of wet-pressing-induced fiber hornification on enzymatic saccharification of lignocelluloses. A wet cellulosic substrate of bleached kraft eucalyptus pulp and two wet sulfite-pretreated lignocellulosic substrates of aspen and lodgepole pine were pressed to various moisture (solids) contents by variation of pressing pressure and pressing...

  3. A saponin-detoxifying enzyme mediates suppression of plant defences

    Science.gov (United States)

    Bouarab, K.; Melton, R.; Peart, J.; Baulcombe, D.; Osbourn, A.

    2002-08-01

    Plant disease resistance can be conferred by constitutive features such as structural barriers or preformed antimicrobial secondary metabolites. Additional defence mechanisms are activated in response to pathogen attack and include localized cell death (the hypersensitive response). Pathogens use different strategies to counter constitutive and induced plant defences, including degradation of preformed antimicrobial compounds and the production of molecules that suppress induced plant defences. Here we present evidence for a two-component process in which a fungal pathogen subverts the preformed antimicrobial compounds of its host and uses them to interfere with induced defence responses. Antimicrobial saponins are first hydrolysed by a fungal saponin-detoxifying enzyme. The degradation product of this hydrolysis then suppresses induced defence responses by interfering with fundamental signal transduction processes leading to disease resistance.

  4. Pretreatments employed in lignocellulosic materials for bioethanol production: an overview

    OpenAIRE

    Danay Carrillo-Nieves; Lourdes Zumalacárregui-de Cárdenas; Olga Sánchez-Collazo; Georgina Michelena-Alvarez; Hector Yznaga-Blanco; José Luis Martínez-Hernández; Cristóbal Noé-Aguilar

    2014-01-01

    Lignocellulosic materials are raw materials with high cellulose content and they constitute the most abun- dant sources of biomass on planet. They are attractive for their low cost and high availability in diverse climates and places for the bioethanol production, however, the main impediment for its use is the appro- priate selection from the technological and economic point of view of the stages of pretreatments and hydrolysis, that allow the breaking down of the lignocellulosic matrix to o...

  5. Enhanced bioprocessing of lignocellulose: Wood-rot fungal saccharification and fermentation of corn fiber to ethanol

    Science.gov (United States)

    Shrestha, Prachand

    no improvement in ethanol yields. We showed that saccharification of lignocellulosic material with a wood-rot fungal process is quite feasible. Corn fiber from wet milling was best degraded to sugars using aerobic solid state fermentation with the soft-rot fungus T. reesei. However, it was shown that both the white-rot fungus P. chrysosporium and brown-rot fungus G. trabeum had the ability to produce additional consortia of hemi/cellulose degrading enzymes. It is likely that a consortium of enzymes from these fungi would be the best approach in saccharification of lignocellulose. In all cases, a subsequent anaerobic yeast process under submerged conditions is required to ferment the released sugars to ethanol. To our knowledge, this is the first time report on production of cellulolytic enzymes from wet-milled corn fiber using white- and brown-rot fungi for sequential fermentation of corn fiber hydrolyzate to ethanol. Keywords: lignocellulose, ethanol, biofuel, bioeconomy, biomass, renewable resources, corn fiber, pretreatment, solid-substrate fermentation, simultaneous saccharification and fermentation (SSF), white-rot fungus, brown-rot fungus, soft-rot fungus, fermentable sugars, enzyme activities, cellulytic enzymes Phanerochaete chrysosporium, Gloleophyllum trabeum, Trichoderma reesei, Saccharomyces cerevisiae.

  6. Toxic Compound, Anti-Nutritional Factors and Functional Properties of Protein Isolated from Detoxified Jatropha curcas Seed Cake

    Directory of Open Access Journals (Sweden)

    Worapot Suntornsuk

    2010-12-01

    Full Text Available Jatropha curcas is a multipurpose tree, which has potential as an alternative source for biodiesel. All of its parts can also be used for human food, animal feed, fertilizer, fuel and traditional medicine. J. curcas seed cake is a low-value by-product obtained from biodiesel production. The seed cake, however, has a high amount of protein, with the presence of a main toxic compound: phorbol esters as well as anti-nutritional factors: trypsin inhibitors, phytic acid, lectin and saponin. The objective of this work was to detoxify J. curcas seed cake and study the toxin, anti-nutritional factors and also functional properties of the protein isolated from the detoxified seed cake. The yield of protein isolate was approximately 70.9%. The protein isolate was obtained without a detectable level of phorbol esters. The solubility of the protein isolate was maximal at pH 12.0 and minimal at pH 4.0. The water and oil binding capacities of the protein isolate were 1.76 g water/g protein and 1.07 mL oil/g protein, respectively. The foam capacity and stability, including emulsion activity and stability of protein isolate, had higher values in a range of basic pHs, while foam and emulsion stabilities decreased with increasing time. The results suggest that the detoxified J. curcas seed cake has potential to be exploited as a novel source of functional protein for food applications.

  7. Toxic compound, anti-nutritional factors and functional properties of protein isolated from detoxified Jatropha curcas seed cake.

    Science.gov (United States)

    Saetae, Donlaporn; Suntornsuk, Worapot

    2010-12-28

    Jatropha curcas is a multipurpose tree, which has potential as an alternative source for biodiesel. All of its parts can also be used for human food, animal feed, fertilizer, fuel and traditional medicine. J. curcas seed cake is a low-value by-product obtained from biodiesel production. The seed cake, however, has a high amount of protein, with the presence of a main toxic compound: phorbol esters as well as anti-nutritional factors: trypsin inhibitors, phytic acid, lectin and saponin. The objective of this work was to detoxify J. curcas seed cake and study the toxin, anti-nutritional factors and also functional properties of the protein isolated from the detoxified seed cake. The yield of protein isolate was approximately 70.9%. The protein isolate was obtained without a detectable level of phorbol esters. The solubility of the protein isolate was maximal at pH 12.0 and minimal at pH 4.0. The water and oil binding capacities of the protein isolate were 1.76 g water/g protein and 1.07 mL oil/g protein, respectively. The foam capacity and stability, including emulsion activity and stability of protein isolate, had higher values in a range of basic pHs, while foam and emulsion stabilities decreased with increasing time. The results suggest that the detoxified J. curcas seed cake has potential to be exploited as a novel source of functional protein for food applications.

  8. Community Structure and Succession Regulation of Fungal Consortia in the Lignocellulose-Degrading Process on Natural Biomass

    Directory of Open Access Journals (Sweden)

    Baoyu Tian

    2014-01-01

    Full Text Available The study aims to investigate fungal community structures and dynamic changes in forest soil lignocellulose-degrading process. rRNA gene clone libraries for the samples collected in different stages of lignocellulose degradation process were constructed and analyzed. A total of 26 representative RFLP types were obtained from original soil clone library, including Mucoromycotina (29.5%, unclassified Zygomycetes (33.5%, Ascomycota (32.4%, and Basidiomycota (4.6%. When soil accumulated with natural lignocellulose, 16 RFLP types were identified from 8-day clone library, including Basidiomycota (62.5%, Ascomycota (36.1%, and Fungi incertae sedis (1.4%. After enrichment for 15 days, identified 11 RFLP types were placed in 3 fungal groups: Basidiomycota (86.9%, Ascomycota (11.5%, and Fungi incertae sedis (1.6%. The results showed richer, more diversity and abundance fungal groups in original forest soil. With the degradation of lignocellulose, fungal groups Mucoromycotina and Ascomycota decreased gradually, and wood-rotting fungi Basidiomycota increased and replaced the opportunist fungi to become predominant group. Most of the fungal clones identified in sample were related to the reported lignocellulose-decomposing strains. Understanding of the microbial community structure and dynamic change during natural lignocellulose-degrading process will provide us with an idea and a basis to construct available commercial lignocellulosic enzymes or microbial complex.

  9. Community structure and succession regulation of fungal consortia in the lignocellulose-degrading process on natural biomass.

    Science.gov (United States)

    Tian, Baoyu; Wang, Chunxiang; Lv, Ruirui; Zhou, Junxiong; Li, Xin; Zheng, Yi; Jin, Xiangyu; Wang, Mengli; Ye, Yongxia; Huang, Xinyi; Liu, Ping

    2014-01-01

    The study aims to investigate fungal community structures and dynamic changes in forest soil lignocellulose-degrading process. rRNA gene clone libraries for the samples collected in different stages of lignocellulose degradation process were constructed and analyzed. A total of 26 representative RFLP types were obtained from original soil clone library, including Mucoromycotina (29.5%), unclassified Zygomycetes (33.5%), Ascomycota (32.4%), and Basidiomycota (4.6%). When soil accumulated with natural lignocellulose, 16 RFLP types were identified from 8-day clone library, including Basidiomycota (62.5%), Ascomycota (36.1%), and Fungi incertae sedis (1.4%). After enrichment for 15 days, identified 11 RFLP types were placed in 3 fungal groups: Basidiomycota (86.9%), Ascomycota (11.5%), and Fungi incertae sedis (1.6%). The results showed richer, more diversity and abundance fungal groups in original forest soil. With the degradation of lignocellulose, fungal groups Mucoromycotina and Ascomycota decreased gradually, and wood-rotting fungi Basidiomycota increased and replaced the opportunist fungi to become predominant group. Most of the fungal clones identified in sample were related to the reported lignocellulose-decomposing strains. Understanding of the microbial community structure and dynamic change during natural lignocellulose-degrading process will provide us with an idea and a basis to construct available commercial lignocellulosic enzymes or microbial complex.

  10. Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.

    Science.gov (United States)

    Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon

    2013-02-28

    Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor

  11. Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

    Directory of Open Access Journals (Sweden)

    Wang ZJ

    2013-01-01

    Full Text Available Abstract Background Nonspecific (nonproductive binding (adsorption of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL is a relatively new process, but demonstrated robust performance for sugar and biofuel production from woody biomass especially softwoods in terms of yields and energy efficiencies. This study demonstrated the role of lignin sulfonation in enhancing enzymatic saccharification of lignocelluloses – lignosulfonate from SPORL can improve enzymatic hydrolysis of lignocelluloses, contrary to the conventional belief that lignin inhibits enzymatic hydrolysis due to nonspecific binding of cellulase. Results The study found that lignosulfonate from SPORL pretreatment and from a commercial source inhibits enzymatic hydrolysis of pure cellulosic substrates at low concentrations due to nonspecific binding of cellulase. Surprisingly, the reduction in enzymatic saccharification efficiency of a lignocellulosic substrate was fully recovered as the concentrations of these two lignosulfonates increased. We hypothesize that lignosulfonate serves as a surfactant to enhance enzymatic hydrolysis at higher concentrations and that this enhancement offsets its inhibitive effect from nonspecific binding of cellulase, when lignosulfonate is applied to lignocellulosic solid substrates. Lignosulfonate can block nonspecific binding of cellulase by bound lignin on the solid substrates, in the same manner as a nonionic surfactant, to significantly enhance enzymatic saccharification. This enhancement is linearly proportional to the amount of lignosulfonate applied which is very important to practical applications. For a SPORL-pretreated lodgepole pine solid, 90% cellulose saccharification was achieved at cellulase loading of 13 FPU/g glucan with the application of its

  12. Thermophilic ethanol fermentation from lignocellulose hydrolysate by genetically engineered Moorella thermoacetica.

    Science.gov (United States)

    Rahayu, Farida; Kawai, Yuto; Iwasaki, Yuki; Yoshida, Koichiro; Kita, Akihisa; Tajima, Takahisa; Kato, Junichi; Murakami, Katsuji; Hoshino, Tamotsu; Nakashimada, Yutaka

    2017-12-01

    A transformant of Moorella thermoacetica was constructed for thermophilic ethanol production from lignocellulosic biomass by deleting two phosphotransacetylase genes, pdul1 and pdul2, and introducing the native aldehyde dehydrogenase gene (aldh) controlled by the promoter from glyceraldehyde-3-phosphate dehydrogenase. The transformant showed tolerance to 540mM and fermented sugars including fructose, glucose, galactose and xylose to mainly ethanol. In a mixed-sugar medium of glucose and xylose, all of the sugars were consumed to produce ethanol at the yield of 1.9mol/mol-sugar. The transformant successfully fermented sugars in hydrolysate prepared through the acid hydrolysis of lignocellulose to ethanol, suggesting that this transformant can be used to ferment the sugars in lignocellulosic biomass for ethanol production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Study on Utilization of Detoxified Jatropha curcas Seed Cake Subjected to Solid State Fermentation as a Dietary Supplement in Wistar Rats.

    Science.gov (United States)

    Sharath, Belame S; Muthukumar, Sevva P; Somashekar, Devappa

    2017-01-01

    The presence of anti-nutrients and toxins like phorbol esters in Jatropha curcas seed cake (JSC) limits its application in feeds. This study was done to assess the potential of detoxified JSC as rat feed. The rats were fed a diet containing 0-5 and 10% of detoxified fermented JSC for four weeks. For the group I, only casein diet was used in rat feed as a negative control. For the group II, untreated JSC was used in rat feed as a positive control. For the group III, fermented JSC using Saccharomyces cerevisiae MTCC-36 was used. For the group IV, the fermented JSC treated with 65% ethanol to remove the residual toxic phorbol esters was used as rat feed. The rats fed with untreated JSC showed increased levels of serum liver enzymes as an indication of the onset of liver disease resulting in mortality. In this group, rats died in week 2, confirming that the cake is not safe as feed until it is processed. The rats fed with detoxified JSC with 5 and 10% level survived with no adverse effects, and the performance was on par with the control groups, although the body weight was slightly less compared to control. Therefore, it was concluded that the detoxified JSC might be the potential and alternative source of protein in the animal feedstuffs up to 10% level. There are recent patents also suggesting the use of alternative feed supplements in the animal feed applications. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Simultaneous saccharification and fermentation of alkaline-pretreated corn stover to ethanol using a recombinant yeast strain

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jing; Xia, Liming [Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027 (China)

    2009-10-15

    Bio-ethanol converted from cheap and abundant lignocellulosic materials is a potential renewable resource to replace depleting fossil fuels. Simultaneous saccharification and fermentation (SSF) of alkaline-pretreated corn stover for the production of ethanol was investigated using a recombinant yeast strain Saccharomyces cerevisiae ZU-10. Low cellobiase activity in Trichoderma reesei cellulase resulted in cellobiose accumulation. Supplementing the simultaneous saccharification and fermentation system with cellobiase greatly reduced feedback inhibition caused by cellobiose to the cellulase reaction, thereby increased the ethanol yield. 12 h of enzymatic prehydrolysis at 50 C prior to simultaneous saccharification and fermentation was found to have a negative effect on the overall ethanol yield. Glucose and xylose produced from alkaline-pretreated corn stover could be co-fermented to ethanol effectively by S. cerevisiae ZU-10. An ethanol concentration of 27.8 g/L and the corresponding ethanol yield on carbohydrate in substrate of 0.350 g/g were achieved within 72 h at 33 C with 80 g/L of substrate and enzyme loadings of 20 filter paper activity units (FPU)/g substrate and 10 cellobiase units (CBU)/g substrate. The results are meaningful in co-conversion of cellulose and hemicellulose fraction of lignocellulosic materials to fuel ethanol. (author)

  15. Novel endophytic yeast Rhodotorula mucilaginosa strain PTD3 II: production of xylitol and ethanol in the presence of inhibitors.

    Science.gov (United States)

    Vajzovic, Azra; Bura, Renata; Kohlmeier, Kevin; Doty, Sharon L

    2012-10-01

    A systematic study was conducted characterizing the effect of furfural, 5-hydroxymethylfurfural (5-HMF), and acetic acid concentration on the production of xylitol and ethanol by a novel endophytic yeast, Rhodotorula mucilaginosa strain PTD3. The influence of different inhibitor concentrations on the growth and fermentation abilities of PTD3 cultivated in synthetic nutrient media containing 30 g/l xylose or glucose were measured during liquid batch cultures. Concentrations of up to 5 g/l of furfural stimulated production of xylitol to 77 % of theoretical yield (10 % higher compared to the control) by PTD3. Xylitol yields produced by this yeast were not affected in the presence of 5-HMF at concentrations of up to 3 g/l. At higher concentrations of furfural and 5-HMF, xylitol and ethanol yields were negatively affected. The higher the concentration of acetic acid present in a media, the higher the ethanol yield approaching 99 % of theoretical yield (15 % higher compared to the control) was produced by the yeast. At all concentrations of acetic acid tested, xylitol yield was lowered. PTD3 was capable of metabolizing concentrations of 5, 15, and 5 g/l of furfural, 5-HMF, and acetic acid, respectively. This yeast would be a potent candidate for the bioconversion of lignocellulosic sugars to biochemicals given that in the presence of low concentrations of inhibitors, its xylitol and ethanol yields are stimulated, and it is capable of metabolizing pretreatment degradation products.

  16. Ethanol from lignocellulose - Fermentation inhibitors, detoxification and genetic engineering of Saccharomyces cerevisiae for enhanced resistance

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, Simona

    2000-07-01

    Ethanol can be produced from lignocellulose by first hydrolysing the material to sugars, and then fermenting the hydrolysate with the yeast Saccharomyces cerevisiae. Hydrolysis using dilute sulphuric acid has advantages over other methods, however, compounds which inhibit fermentation are generated during this kind of hydrolysis. The inhibitory effect of aliphatic acids, furans, and phenolic compounds was investigated. The generation of inhibitors during hydrolysis was studied using Norway spruce as raw material. It was concluded that the decrease in the fermentability coincided with increasing harshness of the hydrolysis conditions. The decrease in fermentability was not correlated solely to the content of aliphatic acids or furan derivatives. To increase the fermentability, detoxification is often employed. Twelve detoxification methods were compared with respect to the chemical composition of the hydrolysate and the fermentability after treatment. The most efficient detoxification methods were anion-exchange at pH 10.0, overliming and enzymatic detoxification with the phenol-oxidase laccase. Detailed analyses of ion exchange revealed that anion exchange and unspecific hydrophobic interactions greatly contributed to the detoxification effect, while cation exchange did not. The comparison of detoxification methods also showed that phenolic compounds are very important fermentation inhibitors, as their selective removal with laccase had a major positive effect on the fermentability. Selected compounds; aliphatic acids, furans and phenolic compounds, were characterised with respect to their inhibitory effect on ethanolic fermentation by S. cerevisiae. When aliphatic acids or furans were compared, the inhibitory effects were found to be in the same range, but the phenolic compounds displayed widely different inhibitory effects. The possibility of genetically engineering S. cerevisiae to achieve increased inhibitor resistance was explored by heterologous expression of

  17. Detailed kinetic and heat transport model for the hydrolysis of lignocellulose by anhydrous hydrogen fluoride vapor

    Energy Technology Data Exchange (ETDEWEB)

    Rorrer, G.L.; Mohring, W.R.; Lamport, D.T.A.; Hawley, M.C.

    1988-01-01

    Anhydrous Hydrogen Fluoride (HF) vapor at ambient conditions efficiently and rapidly hydrolyzed lignocellulose to glucose and lignin. The unsteady-state reaction of HF vapor with a single lignocellulose chip was mathematically modeled under conditions where external and internal mass-transfer resistances were minimized. The model incorporated physical adsorption of HF vapor onto the lignocellulosic matrix and solvolysis of cellulose to glucosyl fluoride by adsorbed HF into the differential material and energy balance expressions. Model predictions for the temperature distribution and global glucose yield in the HF-reacting lignocellulose chip as a function of reaction time and HF vapor stream temperature agreed reasonably with the complimentary experimental data. The model correctly predicted that even when mass-transfer resistances for the reaction of HF vapor with a single lignocellulose chip are minimized, external and internal heat-transfer resistances are still significant.

  18. Sustainable Process Design of Lignocellulose based Biofuel

    DEFF Research Database (Denmark)

    Mangnimit, Saranya; Malakul, Pomthong; Gani, Rafiqul

    the production and use of alternative and sustainable energy sources as rapidly as possible. Biofuel is a type of alternative energy that can be produced from many sources including sugar substances (such as sugarcane juice and molasses), starchy materials (such as corn and cassava), and lignocellulosic...... materials such as agricultural residual, straw and wood chips, the residual from wood industry. However, those sugar and starchy materials can be used not only to make biofuels but they are also food sources. Thus, lignocellulosic materials are interesting feed-stocls as they are inexpensive, abundantly...... available, and are also non-food crops. In this respect, Cassava rhizome has several characteristics that make it a potential feedstock for fuel ethanol production. It has high content of cellulose and hemicelluloses . The objective of this paper is to present a study focused on the sustainable process...

  19. Flow-through biological conversion of lignocellulosic biomass

    Science.gov (United States)

    Herring, Christopher D.; Liu, Chaogang; Bardsley, John

    2014-07-01

    The present invention is directed to a process for biologically converting carbohydrates from lignocellulosic biomass comprising the steps of: suspending lignocellulosic biomass in a flow-through reactor, passing a reaction solution into the reactor, wherein the solution is absorbed into the biomass substrate and at least a portion of the solution migrates through said biomass substrate to a liquid reservoir, recirculating the reaction solution in the liquid reservoir at least once to be absorbed into and migrate through the biomass substrate again. The biological converting of the may involve hydrolyzing cellulose, hemicellulose, or a combination thereof to form oligosaccharides, monomelic sugars, or a combination thereof; fermenting oligosaccharides, monomelic sugars, or a combination thereof to produce ethanol, or a combination thereof. The process can further comprise removing the reaction solution and processing the solution to separate the ethanol produced from non-fermented solids.

  20. Reproductive responses and productive characteristics in ewes supplemented with detoxified castor meal for a long period

    Directory of Open Access Journals (Sweden)

    Liliane Moreira Silva

    2014-08-01

    Full Text Available The objective of the present study was to evaluate the effects of supplementation with detoxified castor meal (DCM in the diet of ewes during pregnancy, partum, and post-partum on the weight development of their offspring and at slaughter. The study included 56 ewes with synchronized estrus that were naturally mated. At the beginning of pregnancy and in post-partum, hepatic and renal function-related parameters and progesterone levels were measured. At slaughter, the proximate composition and fatty acid profile were determined in the loin of ewes. There was no effect of diet on reproductive response after estrus synchronization. At the beginning of pregnancy, albumin and creatinine levels were lower in the DCM group. Supplementation with DCM did not alter the weight or body condition of ewes at partum. However, at weaning, the DCM group showed a higher loin-eye area (LEA in relation to the group fed diets without detoxified castor meal (WDCM. At partum, as well as at weaning, the offspring of the ewes supplemented with DCM had a larger LEA than the WDCM group. In post-partum, levels of glucose, urea, protein, and cholesterol were lower in the DCM group. The return to cyclicity was similar in both groups, with an average of 47 days after partum. At slaughter, neither anatomical and carcass components nor the results of the proximate analysis were affected by the type of diet, except for an increase in heptadecanoic acid in the DCM group. Supplementation with detoxified castor meal in the diet of ewes does not affect lambing, pregnancy, prolificacy, return to cyclicity, milk production, blood biochemical parameters, or carcass characteristics.

  1. Flow-through pretreatment of lignocellulosic biomass with inorganic nanoporous membranes

    Energy Technology Data Exchange (ETDEWEB)

    Bhave, Ramesh R.; Lynd, Lee; Shao, Xiongjun

    2018-04-03

    A process for the pretreatment of lignocellulosic biomass is provided. The process generally includes flowing water through a pretreatment reactor containing a bed of particulate ligno-cellulosic biomass to produce a pressurized, high-temperature hydrolyzate exit stream, separating solubilized compounds from the hydrolyzate exit stream using an inorganic nanoporous membrane element, fractionating the retentate enriched in solubilized organic components and recycling the permeate to the pretreatment reactor. The pretreatment process provides solubilized organics in concentrated form for the subsequent conversion into biofuels and other chemicals.

  2. Process for purifying lignocellulosic feedstocks

    Science.gov (United States)

    Gray, Matthew; Matthes, Megan; Nelson, Thomas; Held, Andrew

    2018-01-09

    The present invention includes methods for removing mineral acids, mineral salts and contaminants, such as metal impurities, ash, terpenoids, stilbenes, flavonoids, proteins, and other inorganic products, from a lignocellulosic feedstock stream containing organic acids, carbohydrates, starches, polysaccharides, disaccharides, monosaccharides, sugars, sugar alcohols, phenols, cresols, and other oxygenated hydrocarbons, in a manner that maintains a portion of the organic acids and other oxygenated hydrocarbons in the product stream.

  3. The yeast ADH7 promoter enables gene expression under pronounced translation repression caused by the combined stress of vanillin, furfural, and 5-hydroxymethylfurfural.

    Science.gov (United States)

    Ishida, Yoko; Nguyen, Trinh Thi My; Izawa, Shingo

    2017-06-20

    Lignocellulosic biomass conversion inhibitors such as vanillin, furfural, and 5-hydroxymethylfurfural (HMF) inhibit the growth of and fermentation by Saccharomyces cerevisiae. A high concentration of each fermentation inhibitor represses translation and increases non-translated mRNAs. We previously reported that the mRNAs of ADH7 and BDH2, which encode putative NADPH- and NADH-dependent alcohol dehydrogenases, respectively, were efficiently translated even with translation repression in response to severe vanillin stress. However, the combined effects of these fermentation inhibitors on the expression of ADH7 and BDH2 remain unclear. We herein demonstrated that exposure to a combined stress of vanillin, furfural, and HMF repressed translation. The protein synthesis of Adh7, but not Bdh2 was significantly induced under combined stress conditions, even though the mRNA levels of ADH7 and BDH2 were up-regulated. Additionally, adh7Δ cells were more sensitive to the combined stress than wild-type and bdh2Δ cells. These results suggest that induction of the ADH7 expression plays a role in the tolerance to the combined stress of vanillin, furfural, and HMF. Furthermore, we succeeded in improving yeast tolerance to the combined stress by controlling the expression of ALD6 with the ADH7 promoter. Our results demonstrate that the ADH7 promoter can overcome the pronounced translation repression caused by the combined stress of vanillin, furfural, and HMF, and also suggest a new gene engineering strategy to breed robust and optimized yeasts for bioethanol production from a lignocellulosic biomass. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Fermentation of hexoses and pentoses from hydrolyzed soybean hull into ethanol and xylitol by Candida guilliermondii BL 13

    Directory of Open Access Journals (Sweden)

    F. da Cunha-Pereira

    Full Text Available Abstract This work investigated the ability of a recently isolated strain of Candida guilliermondii to convert hexoses and pentoses obtained from acid-enzymatic soybean hull hydrolysates into ethanol and, in smaller amounts, into xylitol. Operational conditions and media formulation were optimized concerning ethanol production using experimental designs (Plackett-Burman and Central Composite Design. Results showed that C. guilliermondii BL 13 was capable of growing in non-supplemented, non-detoxified biomass hydrolysates, and the best culture conditions were determined to be 28 °C, pH 5.0, and 109 CFU mL-1 of inoculum size. Ethanol productivity reached 1.4 g L-1 h-1, and maximal yields of 0.41 g g-1 were obtained, representing 80.4 % of the expected theoretical yields, whereas small amounts of xylitol were also produced. These results suggest that C. guilliermondii BL13 is a potentially useful yeast strain to be applied in second-generation ethanol production from lignocellulosic biomass based on its natural capacity to metabolize C-5 and C-6 sugars.

  5. Preparation, characterization, and microbial degradation of specifically radiolabeled [14C]lignocelluloses from marine and fresh water macrophytes

    International Nuclear Information System (INIS)

    Benner, R.; Maccubbin, A.E.; Hodson, R.E.

    1984-01-01

    Specifically radiolabeled [ 14 C-lignin]lignocelluloses were prepared from the aquatic macrophytes Spartina alterniflora, Juncus roemerianus, Rhizophora mangle, and Carex walteriana by using [ 14 C]phenylalanine, [ 14 C]tyrosine, and [ 14 C]cinnamic acid as precursors. Specifically radiolabeled [ 14 C-polysaccharide]lignocelluloses were prepared by using [ 14 C]glucose as precursor. The rates of microbial degradation varied among [ 14 C-lignin]lignocelluloses labeled with different lignin precursors within the same plant species. In herbaceous plants, significant amounts (8 to 24%) of radioactivity from [ 14 C]phenylalanine and [ 14 C]tyrosine were found associated with protein. Microbial degradation of radiolabeled protein resulted in overestimation of lignin degradation rates in lignocelluloses derived from herbaceous aquatic plants. Other differences in degradation rates among [ 14 C-lignin]lignocelluloses from the same plant species were attributable to differences in the amount of label being associated with ester-linked subunits of peripheral lignin. After acid hydrolysis of [ 14 C-polysaccharide]lignocelluloses, radioactivity was detected in several sugars, although most of the radioactivity was distributed between glucose and xylose. After 576 h of incubation with salt marsh sediments, 38% of the polysaccharide component and between 6 and 16% of the lignin component (depending on the precursor) of J. roemerianus lignocellulose was mineralized to 14 CO 2 ; during the same incubation period, 30% of the polysaccharide component and between 12 and 18% of the lignin component of S. alterniflora lignocellulose was mineralized

  6. Production of bioethanol from lignocellulosic materials via the biochemical pathway: A review

    International Nuclear Information System (INIS)

    Balat, Mustafa

    2011-01-01

    Bioethanol is by far the most widely used biofuel for transportation worldwide. Production of bioethanol from biomass is one way to reduce both consumption of crude oil and environmental pollution. Bioethanol can be produced from different kinds of raw materials. These raw materials are classified into three categories of agricultural raw materials: simple sugars, starch and lignocellulose. The price of the raw materials is highly volatile, which can highly affect the production costs of the bioethanol. One major problem with bioethanol production is the availability of raw materials for the production. Lignocellulosic biomass is the most promising feedstock considering its great availability and low cost, but the large-scale commercial production of fuel bioethanol from lignocellulosic materials has still not been implemented.

  7. 2G ethanol from the whole sugarcane lignocellulosic biomass.

    Science.gov (United States)

    Pereira, Sandra Cerqueira; Maehara, Larissa; Machado, Cristina Maria Monteiro; Farinas, Cristiane Sanchez

    2015-01-01

    In the sugarcane industry, large amounts of lignocellulosic residues are generated, which includes bagasse, straw, and tops. The use of the whole sugarcane lignocellulosic biomass for the production of second-generation (2G) ethanol can be a potential alternative to contribute to the economic viability of this process. Here, we conducted a systematic comparative study of the use of the lignocellulosic residues from the whole sugarcane lignocellulosic biomass (bagasse, straw, and tops) from commercial sugarcane varieties for the production of 2G ethanol. In addition, the feasibility of using a mixture of these residues from a selected variety was also investigated. The materials were pretreated with dilute acid and hydrolyzed with a commercial enzymatic preparation, after which the hydrolysates were fermented using an industrial strain of Saccharomyces cerevisiae. The susceptibility to enzymatic saccharification was higher for the tops, followed by straw and bagasse. Interestingly, the fermentability of the hydrolysates showed a different profile, with straw achieving the highest ethanol yields, followed by tops and bagasse. Using a mixture of the different sugarcane parts (bagasse-straw-tops, 1:1:1, in a dry-weight basis), it was possible to achieve a 55% higher enzymatic conversion and a 25% higher ethanol yield, compared to use of the bagasse alone. For the four commercial sugarcane varieties evaluated using the same experimental set of conditions, it was found that the variety of sugarcane was not a significant factor in the 2G ethanol production process. Assessment of use of the whole lignocellulosic sugarcane biomass clearly showed that 2G ethanol production could be significantly improved by the combined use of bagasse, straw, and tops, when compared to the use of bagasse alone. The lower susceptibility to saccharification of sugarcane bagasse, as well as the lower fermentability of its hydrolysates, can be compensated by using it in combination with straw

  8. Pyrolysis based bio-refinery for the production of bioethanol from demineralized ligno-cellulosic biomass

    NARCIS (Netherlands)

    Luque, L.; Westerhof, Roel Johannes Maria; van Rossum, G.; Oudenhoven, Stijn; Kersten, Sascha R.A.; Berruti, F.; Rehmann, L.

    2014-01-01

    This paper evaluates a novel biorefinery approach for the conversion of lignocellulosic biomass from pinewood. A combination of thermochemical and biochemical conversion was chosen with the main product being ethanol. Fast pyrolysis of lignocellulosic biomasss with fractional condensation of the

  9. Factors affecting seawater-based pretreatment of lignocellulosic date palm residues

    DEFF Research Database (Denmark)

    Fang, Chuanji; Thomsen, Mette Hedegaard; Frankaer, Christian Grundahl

    2017-01-01

    Seawater-based pretreatment of lignocellulosic biomass is an innovative process at research stage. With respect to process optimization, factors affecting seawater-based pretreatment of lignocellulosic date palm residues were studied for the first time in this paper. Pretreatment temperature (180...... °C–210 °C), salinity of seawater (0 ppt–50 ppt), and catalysts (H2SO4, Na2CO3, and NaOH) were investigated. The results showed that pretreatment temperature exerted the largest influence on seawater-based pretreatment in terms of the enzymatic digestibility and fermentability of pretreated solids...

  10. Lignocellulose fractionation into furfural and glucose by AlCl3-catalyzed DES/MIBK biphasic pretreatment.

    Science.gov (United States)

    Wang, Zhi-Kun; Shen, Xiao-Jun; Chen, Jun-Jie; Jiang, Ying-Qiu; Hu, Zhi-Yan; Wang, Xing; Liu, Li

    2018-06-01

    Herein, an efficient DES/MIBK biphasic pretreatment system for preparation of furfural and fermentable glucose from lignocellulose was developed with AlCl 3 as catalysis. The low-cost and renewable DES (Choline chloride-Oxalic acid) served not only as a Brønsted acid catalyst, but also as a pretreatment solvent in present work, and MIBK as an extracting reagent which can increase the yield of furfural in DES phase. The effects of this biphasic pretreatment on the furfural yield and saccharification of the lignocellulose before and after pretreatment were explored using HPLC, HAPEC, FT-IR, XRD and SEM. Under the best pretreatment condition (at 140 °C for 90 min), furfural could be obtained in 70.3% yield and 80.8% of the pretreated lignocellulose was saccharified, which was 8.4 times higher than that of the raw lignocellulose without pretreatment. In a word, this pretreatment system can be considered as a potential technique for efficient valorization of lignocellulose for production of furfural and fermentable glucose. Copyright © 2018. Published by Elsevier B.V.

  11. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    Energy Technology Data Exchange (ETDEWEB)

    Wilczek, Grazyna [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Babczynska, Agnieszka [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Augustyniak, Maria [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland); Migula, Pawel [Department of Animal Physiology and Ecotoxicology, University of Silesia, Bankowa 9, 40-007 Katowice (Poland)]. E-mail: migula@us.edu.pl

    2004-12-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex.

  12. Relations between metals (Zn, Pb, Cd and Cu) and glutathione-dependent detoxifying enzymes in spiders from a heavy metal pollution gradient

    International Nuclear Information System (INIS)

    Wilczek, Grazyna; Babczynska, Agnieszka; Augustyniak, Maria; Migula, Pawel

    2004-01-01

    We studied the relations between glutathione-dependent detoxifying enzymes and heavy metal burdens in the web-building spider Agelena labyrinthica (Agelenidae) and the wolf spider Pardosa lugubris (Lycosidae) from five meadow sites along a heavy metal pollution gradient. We assayed the activity of glutathione-S-transferase (GST) and glutathione peroxidases (GPOX, GSTPx), and glutathione (GSH) levels in both sexes. Except for GSH vs Pb content, we found significant correlations between GPOX and GSTPx activity and metal concentrations in females of A. labyrinthica. The highest activity of these enzymes measured in the web-building spiders was found in the individuals from the most polluted sites. In P. lugubris males significant correlations were found between GST and Pb and Zn concentrations, and between GPOX and GSTPx and the concentration of Cu. GST activity was higher in males collected from less polluted areas. Thus, detoxifying strategies against pollutants seemed to be sex-dependent. Actively hunting spiders had higher metal concentrations, maintaining lower activity of detoxifying enzymes and a lower glutathione level. - Capsule: Glutathione-linked enzyme activity in spiders from polluted areas depends on hunting strategy and sex

  13. Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions

    Directory of Open Access Journals (Sweden)

    Flávia Bottino

    2016-06-01

    Full Text Available Abstract Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40 °C. Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days. After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic. However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity and carbon release.

  14. Cognitive performance of detoxified alcoholic Korsakoff syndrome patients remains stable over two years.

    Science.gov (United States)

    Fujiwara, Esther; Brand, Matthias; Borsutzky, Sabine; Steingass, Hans-P; Markowitsch, Hans J

    2008-07-01

    Excessive alcohol consumption is assumed to promote cognitive decline, eventually increasing the risk of dementia. However, little is known about the time course of cognitive functions in patients with chronic alcoholic Korsakoff syndrome (KS). Therefore, we assessed neuropsychological performance in 20 detoxified chronic KS inpatients at time 1 (T1) with a follow-up after two years (T2). The neuropsychological tests assessed verbal and visual short- and long-term memory, working memory, basic executive functions, language, general knowledge, and visual-spatial abilities. Surveys with caregivers and medical records provided information about current and previous disease-related parameters, drinking history, additional pathologies, as well as psychosocial and cognitive therapy within the two-year period. At both sessions, the majority of the KS patients' results were inferior to those of normal subjects. Comparing T1 and T2 revealed no significant decline in any of the investigated functions. Instead, general knowledge, visual long-term memory, and verbal fluency improved slightly after two years, though they still remained within pathological range. Comparing most improved and most deteriorated patients, better outcome occurred more frequently in men than women and was associated with higher premorbid education and fewer detoxifications in the past. In this sample of detoxified KS patients there was no indication of accelerated cognitive decline or onset of dementia-like symptoms over two years.

  15. Lignocellulosic Biobutanol as Fuel for Diesel Engines

    Directory of Open Access Journals (Sweden)

    Martin Pexa

    2016-05-01

    Full Text Available Energy recovery of lignocellulosic waste material in the form of liquid fractions can yield alcohol-based fuels such as bioethanol or biobutanol. This study examined biobutanol derived from lignocellulosic material that was then used as an additive for diesel engines. Biobutanol was used in fuel mixtures with fatty acid methyl ester (FAME obtained by esterification of animal fat (also a waste material in the amounts of 10%, 30%, and 50% butanol. 100% diesel and 100% FAME were used as reference fuels. The evaluation concerned the fuel’s effect on the external speed characteristics, harmful exhaust emissions, and fuel consumption while using the Non-Road Steady Cycle test. When the percentage of butanol was increased, the torque and the power decreased and the brake specific fuel consumption increased. The main advantage of using biobutanol in fuel was its positive effect on reducing the fuel’s viscosity.

  16. Enhancement of fermentable sugar yield by competitive adsorption of non-enzymatic substances from yeast and cellulase on lignin.

    Science.gov (United States)

    Tang, Yong; Lei, Fuhou; Cristhian, Carrasco; Liu, Zuguang; Yu, Hailong; Jiang, Jianxin

    2014-03-20

    Enhancement of enzymatic digestibility by some supplementations could reduce enzyme loading and cost, which is still too high to realize economical production of lignocellulosic biofuels. A recent study indicates that yeast hydrolysates (YH) have improved the efficiency of cellulases on digestibility of furfural residues (FR). In the current work, the components of YH were separated by centrifugation and size exclusion chromatography and finally characterized in order to better understand this positive effect. A 60.8% of nitrogen of yeast cells was remained in the slurry (YHS) after hydrothermal treatment. In the supernatant of YH (YHL), substances of high molecular weight were identified as proteins and other UV-absorbing compounds, which showed close molecular weight to components of cellulases. Those substances attributed to a synergetic positive effect on enzymatic hydrolysis of FR. The fraction of YHL ranged from 1.19 to 2.19 mL (elution volume) contained over 50% of proteins in YHL and had the best performance in stimulating the release of glucose. Experiment results proved the adsorption of proteins in YHL on lignin. Supplementation of cellulases with YH enhances enzymatic digestibility of FR mainly by a competitive adsorption of non-enzymatic substances on lignin. The molecular weight of these substances has a significant impact on their performance. Different strategies can be used for a good utilization of yeast cells in terms of biorefinery concept.

  17. Study of the formation of polyethylene composites and lignocellulose materials by means of irradiation and extrusion

    International Nuclear Information System (INIS)

    Azevedo, Marcos Bertrand de; Romero, Guillermo R.; Gonzalez, Maria Elisa; Smolko, Eduardo E.

    2000-01-01

    One of the greatest opportunities for using of biomass as a precursor in the production of polymeric materials is the lignocellulose composites that can combine high performance with low costs. This work is a initial study on the production of a lignocellulose reinforced polyethylene composite. A compatibilization made by a induced gamma radiation grafting reaction was used to increase the adhesion between the matrix and the reinforced or filled fibers. The lignocellulose materials were exposed to gamma radiation in order to promote a molecular degradation and increase its reactivity. The polymer, the lignocellulose material and the compatibilization were processed by extrusion and the composite produced by this process were characterized by mechanical tests. (author)

  18. Ionic liquid-facilitated preparation of lignocellulosic composites

    Science.gov (United States)

    Lignocellulosic composites (LCs) were prepared by partially dissolving cotton along with steam exploded Aspen wood and burlap fabric reinforcements utilizing an ionic liquid (IL) solvent. Two methods of preparation were employed. In the first method, a controlled amount of IL was added to preassembl...

  19. Pretreatment of lignocellulosic biomass using Fenton chemistry

    Science.gov (United States)

    Pretreatment is a necessary step in “biomass to biofuel conversion” due to the recalcitrant nature of lignocellulosic biomass. White-rot fungi utilize peroxidases and hydrogen peroxide (in vivo Fenton chemistry) to degrade lignin. In an attempt to mimic this process, solution phase Fenton chemistry ...

  20. Lignocellulosic enzymes from Flavodon flavus, a fungus isolated ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-09-03

    Sep 3, 2008 ... es have been shown to degrade not only lignocellulose, but also recalcitrant .... Decolorization of the supernatant was detected by UV spectropho- ... cia, Sweden) packed with polystyrene matrix with quaternary ammonium ...

  1. High-throughput microplate technique for enzymatic hydrolysis of lignocellulosic biomass.

    Science.gov (United States)

    Chundawat, Shishir P S; Balan, Venkatesh; Dale, Bruce E

    2008-04-15

    Several factors will influence the viability of a biochemical platform for manufacturing lignocellulosic based fuels and chemicals, for example, genetically engineering energy crops, reducing pre-treatment severity, and minimizing enzyme loading. Past research on biomass conversion has focused largely on acid based pre-treatment technologies that fractionate lignin and hemicellulose from cellulose. However, for alkaline based (e.g., AFEX) and other lower severity pre-treatments it becomes critical to co-hydrolyze cellulose and hemicellulose using an optimized enzyme cocktail. Lignocellulosics are appropriate substrates to assess hydrolytic activity of enzyme mixtures compared to conventional unrealistic substrates (e.g., filter paper, chromogenic, and fluorigenic compounds) for studying synergistic hydrolysis. However, there are few, if any, high-throughput lignocellulosic digestibility analytical platforms for optimizing biomass conversion. The 96-well Biomass Conversion Research Lab (BCRL) microplate method is a high-throughput assay to study digestibility of lignocellulosic biomass as a function of biomass composition, pre-treatment severity, and enzyme composition. The most suitable method for delivering milled biomass to the microplate was through multi-pipetting slurry suspensions. A rapid bio-enzymatic, spectrophotometric assay was used to determine fermentable sugars. The entire procedure was automated using a robotic pipetting workstation. Several parameters that affect hydrolysis in the microplate were studied and optimized (i.e., particle size reduction, slurry solids concentration, glucan loading, mass transfer issues, and time period for hydrolysis). The microplate method was optimized for crystalline cellulose (Avicel) and ammonia fiber expansion (AFEX) pre-treated corn stover. Copyright 2008 Wiley Periodicals, Inc.

  2. MULTIVARIATE TECHNIQUES APPLIED TO EVALUATION OF LIGNOCELLULOSIC RESIDUES FOR BIOENERGY PRODUCTION

    Directory of Open Access Journals (Sweden)

    Thiago de Paula Protásio

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812361The evaluation of lignocellulosic wastes for bioenergy production demands to consider several characteristicsand properties that may be correlated. This fact demands the use of various multivariate analysis techniquesthat allow the evaluation of relevant energetic factors. This work aimed to apply cluster analysis and principalcomponents analyses for the selection and evaluation of lignocellulosic wastes for bioenergy production.8 types of residual biomass were used, whose the elemental components (C, H, O, N, S content, lignin, totalextractives and ashes contents, basic density and higher and lower heating values were determined. Bothmultivariate techniques applied for evaluation and selection of lignocellulosic wastes were efficient andsimilarities were observed between the biomass groups formed by them. Through the interpretation of thefirst principal component obtained, it was possible to create a global development index for the evaluationof the viability of energetic uses of biomass. The interpretation of the second principal component alloweda contrast between nitrogen and sulfur contents with oxygen content.

  3. Biodegradation of lignocellulosic materials: Present status and future prospects

    International Nuclear Information System (INIS)

    Morrison, I.M.; Brice, R.E.; Mousdale, S.A.

    1989-01-01

    The biodegradation of lignocellulosic material depends on the source and prior treatment of the substrate. As the composition of the substrate influences the mode of degradation, a resume of the structure of cell wall components is given. This shows the relationship between cellulose, hemicelluloses, lignin and the other non-carbohydrate components and how they are arranged within the wall architecture. A summary is given of the different types of enzymes which can attack lignocellulosics, some limitations on their use, and how they can be influenced by other methods of pretreatment. The role of different types of microorganisms is discussed and the paper concludes with some results from work by the authors. (author). 37 refs, 4 figs

  4. Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions.

    Science.gov (United States)

    Bottino, Flávia; Cunha-Santino, Marcela Bianchessi; Bianchini, Irineu

    2016-01-01

    Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40°C). Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively) were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days). After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic). However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity) and carbon release. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  5. Lignosulfonate To Enhance Enzymatic Saccharification of Lignocelluloses: Role of Molecular Weight and Substrate Lignin

    Science.gov (United States)

    Haifeng Zhou; Hongming Lou; Dongjie Yang; J.Y. Zhu; Xueqing Qiu

    2013-01-01

    This study conducted an investigation of the effect of lignosulfonate (LS) on enzymatic saccharification of lignocelluloses. Two commercial LSs and one laboratory sulfonated kraft lignin were applied to Whatman paper, dilute acid and SPORL (sulfite pretreatment to overcome recalcitrance of lignocelluloses) pretreated aspen, and kraft alkaline and SPORL pretreated...

  6. Organic solvent pretreatment of lignocellulosic biomass for biofuels and biochemicals: A review.

    Science.gov (United States)

    Zhang, Ke; Pei, Zhijian; Wang, Donghai

    2016-01-01

    Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Pretreatment is an essential component of biomass conversion process, affecting a majority of downstream processes, including enzymatic hydrolysis, fermentation, and final product separation. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Objectives of this review were to update and extend previous works on pretreatment of lignocellulosic biomass for biofuels and biochemicals using organic solvents, especially on ethanol, methanol, ethylene glycol, glycerol, acetic acid, and formic acid. Perspectives and recommendations were given to fully describe implementation of proper organic solvent pretreatment for future research. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Physico-Chemical Alternatives in Lignocellulosic Materials in Relation to the Kind of Component for Fermenting Purposes

    Directory of Open Access Journals (Sweden)

    Alberto Coz

    2016-07-01

    Full Text Available The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and -bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO2, due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given.

  8. Oxalic acid has an additional, detoxifying function in Sclerotinia sclerotiorum pathogenesis.

    Directory of Open Access Journals (Sweden)

    Annerose Heller

    Full Text Available The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi. Calcium oxalate crystals were detected in advanced (36-48 hpi and late (72 hpi infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages.

  9. Enhanced Ethanol Production with Mixed Lignocellulosic Substrates from Commercial Furfural and Cassava Residues

    Directory of Open Access Journals (Sweden)

    Li Ji

    2015-01-01

    Full Text Available Simultaneous saccharification and fermentation (SSF is an attractive process configuration for bio-ethanol production. Further reductions in process cost of SSF are expected with the use of waste agricultural or industrial materials as feedstock. In the current study, two industrial lignocellulosic wastes, cassava residues (CR and furfural residues (FR, were combined during SSF for ethanol production due to their value-added applications and positive environmental impacts. After CR were liquefied and saccharified, saccharification liquid was added to SSF of FR. The effect of substrate fractions was investigated in terms of ethanol yield, byproduct concentration and the number of yeast cells. Besides, a natural surfactant, Gleditsia saponin, was added to investigate the effect of FR lignin on SSF with 20% substrate concentration. The results showed that increasing the ratio of CR/FR improved the ethanol yield and that the ethanol yield was also increased gradually by increasing the substrate concentration from 6% to 12%. A high ethanol concentration of 36.0 g/L was obtained under the condition of CR:FR = 2:1 with 12% substrate concentration, reaching 71.1% of the theoretical yield. However, Gleditsia saponin did not affect the ethanol yield, indicating the insignificant effect of lignin in SSF with low lignin content in the reaction system.

  10. Application of next-generation sequencing methods for microbial monitoring of anaerobic digestion of lignocellulosic biomass.

    Science.gov (United States)

    Bozan, Mahir; Akyol, Çağrı; Ince, Orhan; Aydin, Sevcan; Ince, Bahar

    2017-09-01

    The anaerobic digestion of lignocellulosic wastes is considered an efficient method for managing the world's energy shortages and resolving contemporary environmental problems. However, the recalcitrance of lignocellulosic biomass represents a barrier to maximizing biogas production. The purpose of this review is to examine the extent to which sequencing methods can be employed to monitor such biofuel conversion processes. From a microbial perspective, we present a detailed insight into anaerobic digesters that utilize lignocellulosic biomass and discuss some benefits and disadvantages associated with the microbial sequencing techniques that are typically applied. We further evaluate the extent to which a hybrid approach incorporating a variation of existing methods can be utilized to develop a more in-depth understanding of microbial communities. It is hoped that this deeper knowledge will enhance the reliability and extent of research findings with the end objective of improving the stability of anaerobic digesters that manage lignocellulosic biomass.

  11. Evaluation of the biomass potential for the production of lignocellulosic bioethanol from various agricultural residues in Austria and Worldwide

    Science.gov (United States)

    Kahr, Heike; Steindl, Daniel; Wimberger, Julia; Schürz, Daniel; Jäger, Alexander

    2013-04-01

    Due to the fact that the resources of fossil fuels are steadily decreasing, researchers have been trying to find alternatives over the past few years. As bioethanol of the first generation is based on potential food, its production has become an increasingly controversial topic. Therefore the focus of research currently is on the production of bioethanol of the second generation, which is made from cellulosic and lignocellulosic materials. However, for the production of bioethanol of the second generation the fibres have to be pre-treated. In this work the mass balances of various agricultural residues available in Austria were generated and examined in lab scale experiments for their bioethanol potential. The residues were pretreatment by means of state of the art technology (steam explosion), enzymatically hydrolysed and fermented with yeast to produce ethanol. Special attention was paid the mass balance of the overall process. Due to the pretreatment the proportion of cellulose increases with the duration of the pre-treatment, whereby the amount of hemicellulose decreases greatly. However, the total losses were increasing with the duration of the pre-treatment, and the losses largely consist of hemicellulose. The ethanol yield varied depending on the cellulose content of the substrates. So rye straw 200 °C 20 min reaches an ethanol yield of 169 kg/t, by far the largest yield. As result on the basis of the annual straw yield in Austria, approximately 210 000 t of bioethanol (266 million litres) could be produced from the straw of wheat (Triticum vulgare), rye (Secale cereale), oat (Avena sativa) and corn (Zea mays) as well as elephant grass (Miscanthus sinensis) using appropriate pre-treatment. So the greenhouse gas emissions produced by burning fossil fuels could be reduced significantly. About 1.8 million tons of motor gasoline are consumed in Austria every year. The needed quantity for a transition to E10 biofuels could thus be easily provided by bioethanol

  12. Molecular microbial ecology of lignocellulose mobilisation as a ...

    African Journals Online (AJOL)

    The community structure of complex microbial consortia which develop in lignocellulose packed passive treatment systems for acid mine drainage remediation were investigated. An understanding of interactions between these populations is important in determining mechanisms by which such systems operate.

  13. Microwave-assisted ionic liquid-mediated rapid catalytic conversion of non-edible lignocellulosic Sunn hemp fibres to biofuels.

    Science.gov (United States)

    Paul, Souvik Kumar; Chakraborty, Saikat

    2018-04-01

    Sunn hemp fibre - a cellulose-rich crystalline non-food energy crop, containing 75.6% cellulose, 10.05% hemicellulose, 10.32% lignin, with high crystallinity (80.17%) and degree of polymerization (650) - is identified as a new non-food substrate for lignocellulosic biofuel production. Microwave irradiation is employed to rapidly rupture the cellulose's glycosidic bonds and enhance glucose yield to 78.7% at 160 °C in only 46 min. The reactants - long-chain cellulose, ionic liquid, transition metal catalyst, and water - form a polar supramolecular complex that rotates under the microwave's alternating polarity and rapidly dissipates the electromagnetic energy through molecular collisions, thus accelerating glycosidic bond breakage. In 46 min, 1 kg of Sunn hemp fibres containing 756 g of cellulose produces 595 g of glucose at 160 °C, and 203 g of hydroxymethyl furfural (furanic biofuel precursor) at 180 °C. Yeast mediated glucose fermentation produces 75.6% bioethanol yield at 30 °C, and the ionic liquid is recycled for cost-effectiveness. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Transcriptome analysis of the thermotolerant yeast Kluyveromyces marxianus CCT 7735 under ethanol stress.

    Science.gov (United States)

    Diniz, Raphael Hermano Santos; Villada, Juan C; Alvim, Mariana Caroline Tocantins; Vidigal, Pedro Marcus Pereira; Vieira, Nívea Moreira; Lamas-Maceiras, Mónica; Cerdán, María Esperanza; González-Siso, María-Isabel; Lahtvee, Petri-Jaan; da Silveira, Wendel Batista

    2017-09-01

    The thermotolerant yeast Kluyveromyces marxianus displays a potential to be used for ethanol production from both whey and lignocellulosic biomass at elevated temperatures, which is highly alluring to reduce the cost of the bioprocess. Nevertheless, contrary to Saccharomyces cerevisiae, K. marxianus cannot tolerate high ethanol concentrations. We report the transcriptional profile alterations in K. marxianus under ethanol stress in order to gain insights about mechanisms involved with ethanol response. Time-dependent changes have been characterized under the exposure of 6% ethanol and compared with the unstressed cells prior to the ethanol addition. Our results reveal that the metabolic flow through the central metabolic pathways is impaired under the applied ethanol stress. Consistent with these results, we also observe that genes involved with ribosome biogenesis are downregulated and gene-encoding heat shock proteins are upregulated. Remarkably, the expression of some gene-encoding enzymes related to unsaturated fatty acid and ergosterol biosynthesis decreases upon ethanol exposure, and free fatty acid and ergosterol measurements demonstrate that their content in K. marxianus does not change under this stress. These results are in contrast to the increase previously reported with S. cerevisiae subjected to ethanol stress and suggest that the restructuration of K. marxianus membrane composition differs in the two yeasts which gives important clues to understand the low ethanol tolerance of K. marxianus compared to S. cerevisiae.

  15. Transport biofuel yields from food and lignocellulosic C{sub 4} crops

    Energy Technology Data Exchange (ETDEWEB)

    Reijnders, L. [IBED University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam (Netherlands)

    2010-01-15

    In the near future, the lignocellulosic C{sub 4} crops Miscanthus and switchgrass (Panicum virgatum) are unlikely to outcompete sugarcane (Saccharum officinarum) in net energetic yearly yield of transport biofuel ha{sup -1}. This holds both for the thermochemical conversion into liquid hydrocarbons and the enzymatic conversion into ethanol. Currently, Miscanthus and switchgrass would also not seem able to outcompete corn (Zea mays) in net energetic yearly yield of liquid transport biofuel ha{sup -1}, but further development of these lignocellulosic crops may gradually lead to a different outcome. (author)

  16. 1-Butyl-3-Methylimidazolium Chloride Pretreatment on Malaysia Lignocellulose Wastes

    International Nuclear Information System (INIS)

    Lee, L.P.; Nur Hasyareeda Hassan; Muhammad Rahimi Yusop

    2015-01-01

    Ionic liquids (ILs) are of great interest as potential solvents for the production of fuels from lignocellulose biomass which is a potential source of bio fuels. To study the effects of pretreatment, 1-butyl-3-methylimidazolium chloride ([B mim]Cl) was used to pretreat woody plants, kempas (Koompassia malaccensis) and jelutong (Dyera costulata), and non-woody plants, kenaf (Hibiscus cannabinus) and rice husk (Oryza sativa) at 120 degree Celsius for 24 h. Cellulose was regenerated by the addition of water. The cell wall composition and structure of the lignocellulose bio masses before and after the ILs pretreatment were observed and characterized using field emission scanning electron microscopy (FESEM), attenuated total reflectance fourier transform infrared (ATR FT-IR) spectroscopy, and X-ray diffraction (XRD). After the pretreatment, enzymatic hydrolysis was carried out to identify the total reducing sugars (TRS) yields using dinitrosalicylic acid (DNS) method. Regenerated lignocellulose bio masses resulted in high TRS yields compared to their counter-parts which are in agreement with the findings of FESEM, ATR FT-IR and XRD that exhibited regenerated cellulose were less crystalline and more amorphous upon IL pretreatment. Therefore, kempas and jelutong can be alternate sources for the bio fuels production. (author)

  17. Enzymatic Saccharification of Lignocelluloses Should be Conducted at Elevated pH 5.2-6.2

    Science.gov (United States)

    T.Q. Lan; Hongming Lou; J.Y. Zhu

    2013-01-01

    This study revealed that cellulose enzymatic saccharification response curves of lignocellulosic substrates were very different from those of pure cellulosic substrates in terms of optimal pH and pH operating window. The maximal enzymatic cellulose saccharification of lignocellulosic substrates occurs at substrate suspension

  18. Lignosulfonate-mediated cellulase adsorption: enhanced enzymatic saccharification of lignocellulose through weakening nonproductive binding to lignin

    Science.gov (United States)

    Zhaojiang Wang; JY Zhu; Yingjuan Fu; Menghua Qin; Zhiyong Shao; Jungang Jiang; Fang Yang

    2013-01-01

    Thermochemical pretreatment of lignocellulose is crucial to bioconversion in the fields of biorefinery and biofuels. However, the enzyme inhibitors in pretreatment hydrolysate make solid substrate washing and hydrolysate detoxification indispensable prior to enzymatic hydrolysis. Sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) is a relatively...

  19. Delignification and Enhanced Gas Release from Soil Containing Lignocellulose by Treatment with Bacterial Lignin Degraders.

    Science.gov (United States)

    Rashid, Goran M M; Duran-Pena, Maria Jesus; Rahmanpour, Rahman; Sapsford, Devin; Bugg, Timothy D H

    2017-04-10

    The aim of the study was to isolate bacterial lignin-degrading bacteria from municipal solid waste soil, and to investigate whether they could be used to delignify lignocellulose-containing soil, and enhance methane release. A set of 20 bacterial lignin degraders, including 11 new isolates from municipal solid waste soil, were tested for delignification and phenol release in soil containing 1% pine lignocellulose. A group of 7 strains were then tested for enhancement of gas release from soil containing 1% lignocellulose in small-scale column tests. Using an aerobic pre-treatment, aerobic strains such as Pseudomonas putida showed enhanced gas release from the treated sample, but four bacterial isolates showed 5-10 fold enhancement in gas release in an in situ experiment under microanaerobic conditions: Agrobacterium sp., Lysinibacillus sphaericus, Comamonas testosteroni, and Enterobacter sp.. The results show that facultative anaerobic bacterial lignin degraders found in landfill soil can be used for in situ delignification and enhanced gas release in soil containing lignocellulose. The study demonstrates the feasibility of using an in situ bacterial treatment to enhance gas release and resource recovery from landfill soil containing lignocellulosic waste. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  20. Ethanol production from lignocellulosic hydrolysates using engineered Saccharomyces cerevisiae harboring xylose isomerase-based pathway.

    Science.gov (United States)

    Ko, Ja Kyong; Um, Youngsoon; Woo, Han Min; Kim, Kyoung Heon; Lee, Sun-Mi

    2016-06-01

    The efficient co-fermentation of glucose and xylose is necessary for the economically feasible bioethanol production from lignocellulosic biomass. Even with xylose utilizing Saccharomyces cerevisiae, the efficiency of the lignocellulosic ethanol production remains suboptimal mainly due to the low conversion yield of xylose to ethanol. In this study, we evaluated the co-fermentation performances of SXA-R2P-E, a recently engineered isomerase-based xylose utilizing strain, in mixed sugars and in lignocellulosic hydrolysates. In a high-sugar fermentation with 70g/L of glucose and 40g/L of xylose, SXA-R2P-E produced 50g/L of ethanol with an yield of 0.43gethanol/gsugars at 72h. From dilute acid-pretreated hydrolysates of rice straw and hardwood (oak), the strain produced 18-21g/L of ethanol with among the highest yield of 0.43-0.46gethanol/gsugars ever reported. This study shows a highly promising potential of a xylose isomerase-expressing strain as an industrially relevant ethanol producer from lignocellulosic hydrolysates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Stabilization of wood and lignocellulose materials

    International Nuclear Information System (INIS)

    Pesek, M.; Dedek, V.; Plander, E.; Jarkovsky, J.

    1973-01-01

    A method is described consisting in impregnation of wood or of lignocellulose materials with a mixture containing the unsaturated monomers styrene and acrylnitrile, organic solvents and swelling agents, and 1,3-butadiene and/or 2-chloro-1,3-butadiene and/or 1,3-cyclopentadiene at an amount of 40 volume per cent in the initial mixture. Polymerization is effected by ionizing radiation. (B.S.)

  2. Distinct Domestication Trajectories in Top-Fermenting Beer Yeasts and Wine Yeasts.

    Science.gov (United States)

    Gonçalves, Margarida; Pontes, Ana; Almeida, Pedro; Barbosa, Raquel; Serra, Marta; Libkind, Diego; Hutzler, Mathias; Gonçalves, Paula; Sampaio, José Paulo

    2016-10-24

    Beer is one of the oldest alcoholic beverages and is produced by the fermentation of sugars derived from starches present in cereal grains. Contrary to lager beers, made by bottom-fermenting strains of Saccharomyces pastorianus, a hybrid yeast, ale beers are closer to the ancient beer type and are fermented by S. cerevisiae, a top-fermenting yeast. Here, we use population genomics to investigate (1) the closest relatives of top-fermenting beer yeasts; (2) whether top-fermenting yeasts represent an independent domestication event separate from those already described; (3) whether single or multiple beer yeast domestication events can be inferred; and (4) whether top-fermenting yeasts represent non-recombinant or recombinant lineages. Our results revealed that top-fermenting beer yeasts are polyphyletic, with a main clade composed of at least three subgroups, dominantly represented by the German, British, and wheat beer strains. Other beer strains were phylogenetically close to sake, wine, or bread yeasts. We detected genetic signatures of beer yeast domestication by investigating genes previously linked to brewing and using genome-wide scans. We propose that the emergence of the main clade of beer yeasts is related with a domestication event distinct from the previously known cases of wine and sake yeast domestication. The nucleotide diversity of the main beer clade more than doubled that of wine yeasts, which might be a consequence of fundamental differences in the modes of beer and wine yeast domestication. The higher diversity of beer strains could be due to the more intense and different selection regimes associated to brewing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Lignocellulose pretreatment in a fungus-cultivating termite

    Science.gov (United States)

    Hongjie Li; Daniel J. Yelle; Chang Li; Mengyi Yang; Jing Ke; Ruijuan Zhang; Yu Liu; Na Zhu; Shiyou Liang; Xiaochang Mo; John Ralph; Cameron R. Currie; Jianchu Mo

    2017-01-01

    Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is an essential but challenging starting point for the lignocellulosics industries. The variety of ether– and carbon–carbon interunit linkages produced via radical coupling during lignification limit chemical and biological depolymerization efficiency. In an ancient fungus-cultivating...

  4. Prions in yeast

    OpenAIRE

    Bezdíčka, Martin

    2013-01-01

    The thesis describes yeast prions and their biological effects on yeast in general. It defines the basic characteristics of yeast prions, that distinguish prions from other proteins. The thesis introduces various possibilities of prion formation, and propagation as well as specific types of yeast prions, including various functions of most studied types of prions. The thesis also focuses on chaperones that affect the state of yeast prions in cells. Lastly, the thesis indicates similarities be...

  5. Behavior of detoxifying enzymes of Aedes aegypti exposed to girgensohnine alkaloid analog and Cymbopogon flexuosus essential oil.

    Science.gov (United States)

    Carreño Otero, Aurora L; Palacio-Cortés, Angela Maria; Navarro-Silva, Mario Antonio; Kouznetsov, Vladimir V; Duque L, Jonny E

    2018-01-01

    Because mosquito control depend on the use of commercial insecticides and resistance has been described in some of them, there is a need to explore new molecules no resistant. In vivo effects of girgensohnine analog 2-(3,4-dimethoxyphenyl)-2-(piperidin-1-yl)acetonitrile DPPA and Cymbopogon flexuosus essential oil CFEO, on the detoxifying enzymes acetylcholinesterase (AChE), glutathione-S-transferase (GST), nonspecific esterases (α- and β-), mixed function oxidases (MFO) and p-NPA esterases were evaluated on a Rockefeller (Rock) and wild Aedes aegypti population from Santander, Colombia (WSant). The action was tested after 24h of exposure at concentrations of 20.10, 35.18 and 70.35mgL -1 of DPPA and 18.45, 30.75 and 61.50mgL -1 of CFEO, respectively. It was found that AChE activity of Rock and WSant was not influenced by the evaluated concentration of DPPA and CFEO (p>0.05), while MFO activity was significantly affected by all CFEO concentrations in WSant (p<0.05). GST, α- and β-esterase activities were affected in Rock exposed at the highest CFEO concentration, this concentration also modified β-esterases activity of WSant. DPPA and CFEO sublethal doses induced inhibition of AChE activity on untreated larvae homogenate from 12 to 20% and 18 to 26%, respectively. For untreated adult homogenate, the inhibition activity raised up to 14 to 27% for DPPA and 26 to 34% for CFEO. Elevated levels of detoxifying enzymes, found when CFEO was evaluated, showed a larval sensitivity not observed by the pure compound suggesting that DPPA, contrary to CFEO, was not recognized, transformed or eliminated by the evaluated detoxifying enzymes. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Deconstruction of ionic liquid pretreated lignocellulosic biomass using mono-component cellulases and hemicellulases and commercial mixtures

    Science.gov (United States)

    Lignocellulosic biomass is comprised of cellulose and hemicellulose, sources of polysaccharides, and lignin, a macromolecule with extensive aromaticity. Lignocellulose requires pretreatment before biochemical conversion to its monomeric sugars which can provide a renewable carbon based feedstock for...

  7. Microbial degradation of lignocellulosic fractions during drum composting of mixed organic waste

    Directory of Open Access Journals (Sweden)

    Vempalli Sudharsan Varma

    2017-11-01

    Full Text Available The study aimed to characterize the microbial population involved in lignocellulose degradation during drum composting of mixed organic waste i.e. vegetable waste, cattle manure, saw dust and dry leaves in a 550 L rotary drum composter. Lignocellulose degradation by different microbial populations was correlated by comparing results from four trials, i.e., Trial 1 (5:4, Trial 2 (6:3, Trial 3 (7:2 and Trial 4 (8:1 of varying waste combinations during 20 days of composting period. Due to proper combination of waste materials and agitation in drum composter, a maximum of 66.5 and 61.4 °C was achieved in Trial 1 and 2 by observing a temperature level of 55 °C for 4–6 d. The study revealed that combinations of waste materials had a major effect on the microbial degradation of waste material and quality of final compost due to its physical properties. However, Trial 1 was observed to have longer thermophilic phase leading to higher degradation of lignocellulosic fractions. Furthermore, Fourier transform infrared spectrometer and fluorescent spectroscopy confirmed the decrease in aliphatic to aromatic ratio and increase in polyphenolic compounds of the compost. Heterotrophic bacteria were observed predominantly due to the readily available organic matter during the initial period of composting. However, fungi and actinomycetes were active in the degradation of lignocellulosic fractions.

  8. Complete oxidative conversion of lignocellulose derived non-glucose sugars to sugar acids by Gluconobacter oxydans.

    Science.gov (United States)

    Yao, Ruimiao; Hou, Weiliang; Bao, Jie

    2017-11-01

    Non-glucose sugars derived from lignocellulose cover approximately 40% of the total carbohydrates of lignocellulose biomass. The conversion of the non-glucose sugars to the target products is an important task of lignocellulose biorefining research. Here we report a fast and complete conversion of the total non-glucose sugars from corn stover into the corresponding sugar acids by whole cell catalysis and aerobic fermentation of Gluconobacter oxydans. The conversions include xylose to xylonate, arabinose to arabonate, mannose to mannonate, and galactose to galactonate, as well as with glucose into gluconate. These cellulosic non-glucose sugar acids showed the excellent cement retard setting property. The mixed cellulosic sugar acids could be used as cement retard additives without separation. The conversion of the non-glucose sugars not only makes full use of lignocellulose derived sugars, but also effectively reduces the wastewater treatment burden by removal of residual sugars. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A comprehensive review on pre-treatment strategy for lignocellulosic food industry waste: Challenges and opportunities.

    Science.gov (United States)

    Ravindran, Rajeev; Jaiswal, Amit Kumar

    2016-01-01

    Lignocellulose is a generic term used to describe plant biomass. It is the most abundant renewable carbon resource in the world and is mainly composed of lignin, cellulose and hemicelluloses. Most of the food and food processing industry waste are lignocellulosic in nature with a global estimate of up to 1.3 billion tons/year. Lignocellulose, on hydrolysis, releases reducing sugars which is used for the production of bioethanol, biogas, organic acids, enzymes and biosorbents. However, structural conformation, high lignin content and crystalline cellulose hinder its use for value addition. Pre-treatment strategies facilitate the exposure of more cellulose and hemicelluloses for enzymatic hydrolysis. The present article confers about the structure of lignocellulose and how it influences enzymatic degradation emphasising the need for pre-treatments along with a comprehensive analysis and categorisation of the same. Finally, this article concludes with a detailed discussion on microbial/enzymatic inhibitors that arise post pre-treatment and strategies to eliminate them. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. SIMULTANEOUS PRETREATMENT OF LIGNOCELLULOSE AND HYDROLYSIS OF STARCH IN MIXTURES TO SUGARS

    OpenAIRE

    Hamzeh Hoseinpour; Keikhosro Karimi; Hamid Zilouei; Mohammad J. Taherzadeh

    2010-01-01

    Mixtures of starch and lignocelluloses are available in many industrial, agricultural, and municipal wastes and residuals. In this work, dilute sulfuric acid was used for simultaneous pretreatment of lignocellulose and hydrolysis of starch, to obtain a maximum amount of fermentable sugar after enzymatic hydrolysis with cellulase and β-glucosidase. The acid treatment was carried out at 70-150°C with 0-1% (v/v) acid concentration and 5-15% (w/v) solids concentration for 0-40 minutes. Under the ...

  11. Improving the adsorption of lignocelluloses of prehydrolysis liquor on precipitated calcium carbonate.

    Science.gov (United States)

    Fatehi, Pedram; Shen, Jing; Hamdan, Fadia C; Ni, Yonghao

    2013-02-15

    In this work, the adsorption of lignocelluloses of pre-hydrolysis liquor (PHL) on precipitated calcium carbonate (PCC) was studied in the presence of poly diallyldimethylammonium chloride (PDADMAC) or cationic polyacrylamide (CPAM). The results revealed that adding PCC to PHL and subsequently adding cationic polymers to PHL/PCC systems was more effective than adding cationic polymers to PHL and then adding PCC to the cationic polymer/PHL systems. At the same dosage applied, PDADMAC resulted in a higher adsorption of lignocelluloses on PCC than CPAM did due to its higher charge density. The adsorption of lignocelluloses on PCC reached its maximum in 3h, and a high temperature reduced the adsorption level as the adsorption was an exothermic process. The maximum adsorptions of 530 mg/g oligo-sugars, 203 mg/g lignin and 58 mg/g furfural on PCC were achieved via adding 0.8 mg/g PDADMAC2 (i.e. higher MW PDADMAC) to PCC/PHL system. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Technological advances and applications of hydrolytic enzymes for valorization of lignocellulosic biomass.

    Science.gov (United States)

    Manisha; Yadav, Sudesh Kumar

    2017-12-01

    Hydrolytic enzymes are indispensable tools in the production of various foodstuffs, drugs, and consumables owing to their applications in almost every industrial process nowadays. One of the foremost areas of interest involving the use of hydrolytic enzymes is in the transformation of lignocellulosic biomass into value added products. However, limitations of the processes due to inadequate enzyme activity and stability with a narrow range of pH and temperature optima often limit their effective usage. The innovative technologies, involving manipulation of enzyme activity and stability through mutagenesis, genetic engineering and metagenomics lead to a major leap in all the fields using hydrolytic enzymes. This article provides recent advancement towards the isolation and use of microbes for lignocellulosic biomass utilisation, microbes producing the hydrolytic enzymes, the modern age technologies used to manipulate and enhance the hydrolytic enzyme activity and the applications of such enzymes in value added products development from lignocellulosic biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Fungal treated lignocellulosic biomass as ruminant feed ingredient: a review.

    Science.gov (United States)

    van Kuijk, S J A; Sonnenberg, A S M; Baars, J J P; Hendriks, W H; Cone, J W

    2015-01-01

    In ruminant nutrition, there is an increasing interest for ingredients that do not compete with human nutrition. Ruminants are specialists in digesting carbohydrates in plant cell walls; therefore lignocellulosic biomass has potential in ruminant nutrition. The presence of lignin in biomass, however, limits the effective utilization of cellulose and hemicellulose. Currently, most often chemical and/or physical treatments are used to degrade lignin. White rot fungi are selective lignin degraders and can be a potential alternative to current methods which involve potentially toxic chemicals and expensive equipment. This review provides an overview of research conducted to date on fungal pretreatment of lignocellulosic biomass for ruminant feeds. White rot fungi colonize lignocellulosic biomass, and during colonization produce enzymes, radicals and other small compounds to breakdown lignin. The mechanisms on how these fungi degrade lignin are not fully understood, but fungal strain, the origin of lignocellulose and culture conditions have a major effect on the process. Ceriporiopsis subvermispora and Pleurotus eryngii are the most effective fungi to improve the nutritional value of biomass for ruminant nutrition. However, conclusions on the effectiveness of fungal delignification are difficult to draw due to a lack of standardized culture conditions and information on fungal strains used. Methods of analysis between studies are not uniform for both chemical analysis and in vitro degradation measurements. In vivo studies are limited in number and mostly describing digestibility after mushroom production, when the fungus has degraded cellulose to derive energy for fruit body development. Optimization of fungal pretreatment is required to shorten the process of delignification and make it more selective for lignin. In this respect, future research should focus on optimization of culture conditions and gene expression to obtain a better understanding of the mechanisms

  14. Process Simulation of Biobutanol Production from Lignocellulosic Feedstocks

    NARCIS (Netherlands)

    Procentese, A.; Guida, T.; Raganati, F.; Olivieri, G.; Salatino, P.; Marzocchella, A.

    2014-01-01

    A potential flowsheet to produce butanol production by conversion of a lignocellulosic biomass has been simulated by means of the software Aspen Plus®. The flowsheet has included upstream, fermentation, and downstream sections and the attention has been focused on the upstream section. The proposed

  15. Bioethanol - Status report on bioethanol production from wood and other lignocellulosic feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Scott-Kerr, Chris; Johnson, Tony; Johnson, Barbara; Kiviaho, Jukka

    2010-09-15

    Lignocellulosic biomass is seen as an attractive feedstock for future supplies of renewable fuels, reducing the dependence on imported petroleum. However, there are technical and economic impediments to the development of commercial processes that utilise biomass feedstocks for the production of liquid fuels such as ethanol. Significant investment into research, pilot and demonstration plants is on-going to develop commercially viable processes utilising the biochemical and thermochemical conversion technologies for ethanol. This paper reviews the current status of commercial lignocellulosic ethanol production and identifies global production facilities.

  16. Production of fuel range oxygenates by supercritical hydrothermal liquefaction of lignocellulosic model systems

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Rosendahl, Lasse Aistrup

    2015-01-01

    Lignocellulosic model compounds and aspen wood are processed at supercritical hydrothermal conditions to study and understand feedstock impact on biocrude formation and characteristics. Glucose and xylose demonstrate similar yield of biocrude and biochar, similar biocrude characteristics, and it ......Lignocellulosic model compounds and aspen wood are processed at supercritical hydrothermal conditions to study and understand feedstock impact on biocrude formation and characteristics. Glucose and xylose demonstrate similar yield of biocrude and biochar, similar biocrude characteristics...

  17. Simple and enhanced production of lignocellulosic ethanol by ...

    African Journals Online (AJOL)

    Ethanol can be produced from a fermentation process using raw materials obtained from highly economically important plants such as corn, cassava and sugarcane, and used as an alternative energy source. These economical plants are being used less because their initial cost is still increasing. However, lignocellulosic ...

  18. Bacterial Community Structure and Biochemical Changes Associated With Composting of Lignocellulosic Oil Palm Empty Fruit Bunch

    Directory of Open Access Journals (Sweden)

    Mohd Huzairi Mohd Zainudin

    2013-11-01

    Full Text Available Bacterial community structure and biochemical changes during the composting of lignocellulosic oil palm empty bunch (EFB and palm oil mill effluent (POME anaerobic sludge were studied by examining the succession of the bacterial community and its association with changes in lignocellulosic components by denaturing gradient gel electrophoresis (DGGE and the 16S rRNA gene clone library. During composting, a major reduction in cellulose after 10 days from 50% to 19% and the carbon content from 44% to 27% towards the end of the 40-day composting period were observed. The C/N ratio also decreased. A drastic change in the bacterial community structure and diversity throughout the composting process was clearly observed using PCR-DGGE banding patterns. The bacterial community drastically shifted between the thermophilic and maturing stages. 16s rRNA clones belonging to the genera Bacillus, Exiguobacterium, Desemzia, and Planococcus were the dominant groups throughout composting. The species closely related to Solibacillus silvestris were found to be major contributors to changes in the lignocellulosic component. Clones identified as Thermobacillus xylanilyticus, Brachybacterium faecium, Cellulosimicrobium cellulans, Cellulomonas sp., and Thermobifida fusca, which are known to be lignocellulosic-degrading bacteria, were also detected and are believed to support the lignocellulose degradation.

  19. Radiation stimulation of yeast crops for increasing output of alcohol and baker yeasts

    International Nuclear Information System (INIS)

    Vlad, E.; Marsheu, P.

    1974-01-01

    The purpose of this study was to stimulate by gamma radiation the existing commercial types of yeast so as to obtain yeasts that would better reflect the substrate and have improved reproductive capacity. The experiments were conducted under ordinary conditions using commercial yeasts received from one factory producing alcohol and bakery yeasts and isolated as pure cultures. Irradiating yeast cultures with small doses (up to 10 krad) was found to stimulate the reproduction and fermenting activity of yeast cells as manifested in increased accumulation of yeast biomass and greater yield of ethyl alcohol. (E.T.)

  20. Rapid and Complete Enzyme Hydrolysis of Lignocellulosic Nanofibrils

    Science.gov (United States)

    Raquel Martin-Sampedro; Ilari Filpponen; Ingrid C. Hoeger; J.Y. Zhu; Janne Laine; Orlando J. Rojas

    2012-01-01

    Rapid enzymatic saccharification of lignocellulosic nanofibrils (LCNF) was investigated by monitoring nanoscale changes in mass via quartz crystal microgravimetry and also by measuring reducing sugar yields. In only a few minutes LCNF thin films were completely hydrolyzed upon incubation in multicomponent enzyme systems. Conversion to sugars and oligosaccharides of...

  1. Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

    DEFF Research Database (Denmark)

    Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

    2014-01-01

    production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible...... district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the expected operation pattern of such polygeneration system is taken......Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol...

  2. Pretreatment Technologies of Lignocellulosic Materials in Bioethanol Production Process

    Directory of Open Access Journals (Sweden)

    Mohamad Rusdi Hidayat

    2013-06-01

    Full Text Available Bioethanol is one type of biofuel that developed significantly. The utilization of bioethanol is not only limited for fuel, but also could be used as material for various industries such as pharmaceuticals, cosmetics, and food. With wide utilization and relatively simple production technology has made bioethanol as the most favored biofuel currently. The use of lignocellulosic biomass, microalgae, seaweeds, even GMO (Genetically modified organisms as substrates for bioethanol production has been widely tested. Differences in the materials eventually led to change in the production technology used. Pretreatment technology in the bioethanol production using lignocellulosic currently experiencing rapid development. It is a key process and crucial for the whole next steps. Based on the advantages and disadvantages from all methods, steam explotion and liquid hot water methods are the most promising  pretreatment technology available.

  3. SUMO expression shortens the lag phase of Saccharomyces cerevisiae yeast growth caused by complex interactive effects of major mixed fermentation inhibitors found in hot-compressed water-treated lignocellulosic hydrolysate.

    Science.gov (United States)

    Jayakody, Lahiru N; Kadowaki, Masafumi; Tsuge, Keisuke; Horie, Kenta; Suzuki, Akihiro; Hayashi, Nobuyuki; Kitagaki, Hiroshi

    2015-01-01

    The complex inhibitory effects of inhibitors present in lignocellulose hydrolysate suppress the ethanol fermentation of Saccharomyces cerevisiae. Although the interactive inhibitory effects play important roles in the actual hydrolysate, few studies have investigated glycolaldehyde, the key inhibitor of hot-compressed water-treated lignocellulose hydrolysate. Given this challenge, we investigated the interactive effects of mixed fermentation inhibitors, including glycolaldehyde. First, we confirmed that glycolaldehyde was the most potent inhibitor in the hydrolysate and exerted interactive inhibitory effects in combination with major inhibitors. Next, through genome-wide analysis and megavariate data modeling, we identified SUMOylation as a novel potential mechanism to overcome the combinational inhibitory effects of fermentation inhibitors. Indeed, overall SUMOylation was increased and Pgk1, which produces an ATP molecule in glycolysis by substrate-level phosphorylation, was SUMOylated and degraded in response to glycolaldehyde. Augmenting the SUMO-dependent ubiquitin system in the ADH1-expressing strain significantly shortened the lag phase of growth, released cells from G2/M arrest, and improved energy status and glucose uptake in the inhibitor-containing medium. In summary, our study was the first to establish SUMOylation as a novel platform for regulating the lag phase caused by complex fermentation inhibitors.

  4. Lignocellulosic biomass utilization toward biorefinery using meshophilic Clostridial species

    NARCIS (Netherlands)

    Tamaru, Yutaka; Lopez Contreras, A.M.

    2013-01-01

    Lignocellulosic biomass such as agricultural, industrial, and forestry residues as well as
    dedicated crops constitute renewable and abundant resources with great potential for a lowcost
    and uniquely sustainable bioconversion to value-added bioproducts. Thus, many
    organic fuels and

  5. Green Processing of Lignocellulosic Biomass and Its Derivatives in Deep Eutectic Solvents.

    Science.gov (United States)

    Tang, Xing; Zuo, Miao; Li, Zheng; Liu, Huai; Xiong, Caixia; Zeng, Xianhai; Sun, Yong; Hu, Lei; Liu, Shijie; Lei, Tingzhou; Lin, Lu

    2017-07-10

    The scientific community has been seeking cost-competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents (DESs) are currently emerging as a new class of promising solvents that are generally liquid eutectic mixtures formed by self-association (or hydrogen-bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs. DESs are also employed as effective media for the modification of cellulose to afford functionalized cellulosic materials, such as cellulose nanocrystals. More interestingly, biomassderived carbohydrates, such as fructose, can be used as one of the constituents of DESs and then dehydrated to 5-hydroxymethylfurfural in high yield. In this review, a comprehensive summary of recent contribution of DESs to the processing of lignocellulosic biomass and its derivatives is provided. Moreover, further discussion about the challenges of the application of DESs in biomass processing is presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Increased turnover of dopamine in caudate nucleus of detoxified alcoholic patients

    DEFF Research Database (Denmark)

    Kumakura, Yoshitaka; Gjedde, Albert; Caprioli, Daniele

    2013-01-01

    ventral striatum. We conclude that craving is most pronounced in the individuals with relatively rapid dopamine turnover in the left ventral striatum. The blood-brain clearance rate (K), corrected for subsequent loss of radiolabeled molecules from brain, was completely normal throughout the brain...... of the alcoholics, in whom the volume of distribution (V(d)) was found to be significantly lower in the left caudate nucleus. The magnitude of Vd in the left caudate head was reduced by 43% relative to the 16 controls, consistent with a 58% increase of k(loss). We interpret the findings as indicating that a trait...... for rapid dopamine turnover in the ventral striatum subserves craving and reward-dependence, leading to an acquired state of increased dopamine turnover in the dorsal striatum of detoxified alcoholic patients....

  7. Enzymology of lignocellulose bioconversion by Streptomyces viridosporus

    International Nuclear Information System (INIS)

    Ramachandra, M.

    1989-01-01

    Significant progress has been made in lignin biodegradation research since 1983, when lignin peroxidases were discovered in fungi. A similar breakthrough in bacterial lignin biodegradation research is anticipated. Several laboratories have successfully demonstrated the ability of bacteria to mineralize [ 14 C]-lignin lignocelluloses as well as 14 C-labelled synthetic lignins. Attempts are being made to identify the key enzymes involved. In this dissertation, two studies are presented which address the enzymology of lignin biodegradation by Streptomyces viridosporus. The first study compares selected extracellular enzyme of wild-type and genetically manipulated strains with enhanced abilities to produced a water soluble lignin degradation intermediate, designated acid-precipitable polymeric lignin (APPL). UV irradiation mutant T7A-81 and protoplast fusion recombinant SR-10 had higher and longer persisting peroxidase, esterase, and endoglucanase activity than did the wild type strain T7A. An extracellular lignocellulose-induced peroxidase with some similarities to fungal ligninases was described for the first time in Streptomyces. The second study describes purification and characterization of an extracellular lignin peroxidase produced by S. viridosporus T7A. This is the first report of a lignin peroxidase in any bacterium

  8. Weedy lignocellulosic feedstock and microbial metabolic engineering. Advancing the generation of 'Biofuel'

    Energy Technology Data Exchange (ETDEWEB)

    Chandel, Anuj K. [Jawaharlal Nehru Technological Univ., Hyderabad (India). Centre of Biotechnology; Singh, Om V. [Pittsburgh Univ., Bradford, PA (United States). Div. of Biological and Health Sciences

    2011-03-15

    Lignocellulosic materials are the most abundant renewable organic resources ({proportional_to}200 billion tons annually) on earth that are readily available for conversion to ethanol and other value-added products, but they have not yet been tapped for the commercial production of fuel ethanol. The lignocellulosic substrates include woody substrates such as hardwood (birch and aspen, etc.) and softwood (spruce and pine, etc.), agro residues (wheat straw, sugarcane bagasse, corn stover, etc.), dedicated energy crops (switch grass, and Miscanthus etc.), weedy materials (Eicchornia crassipes, Lantana camara etc.), and municipal solid waste (food and kitchen waste, etc.). Despite the success achieved in the laboratory, there are limitations to success with lignocellulosic substrates on a commercial scale. The future of lignocellulosics is expected to lie in improvements of plant biomass, metabolic engineering of ethanol, and cellulolytic enzyme-producing microorganisms, fullest exploitation of weed materials, and process integration of the individual steps involved in bioethanol production. Issues related to the chemical composition of various weedy raw substrates for bioethanol formation, including chemical composition-based structural hydrolysis of the substrate, need special attention. This area could be opened up further by exploring genetically modified metabolic engineering routes in weedy materials and in biocatalysts that would make the production of bioethanol more efficient. (orig.)

  9. Recent advances in pretreatment of lignocellulosic wastes and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-04-20

    Apr 20, 2009 ... The barrier to the production and recovery of valuable materials from LCW is the structure of lignocellulose which has evolved to resist degradation due to cross- linking between the polysaccharides (cellulose and hemi- cellulose) and the lignin via ester and ether linkages (Yan and Shuya, 2006; Xiao et al., ...

  10. Fatty acids from oleaginous yeasts and yeast-like fungi and their potential applications.

    Science.gov (United States)

    Xue, Si-Jia; Chi, Zhe; Zhang, Yu; Li, Yan-Feng; Liu, Guang-Lei; Jiang, Hong; Hu, Zhong; Chi, Zhen-Ming

    2018-02-01

    Oleaginous yeasts, fatty acids biosynthesis and regulation in the oleaginous yeasts and the fatty acids from the oleaginous yeasts and their applications are reviewed in this article. Oleaginous yeasts such as Rhodosporidium toruloides, Yarrowia lipolytica, Rhodotorula mucilaginosa, and Aureobasidium melanogenum, which can accumulate over 50% lipid of their cell dry weight, have many advantages over other oleaginous microorganisms. The fatty acids from the oleaginous yeasts have many potential applications. Many oleaginous yeasts have now been genetically modified to over-produce fatty acids and their derivatives. The most important features of the oleaginous yeasts are that they have special enzymatic systems for enhanced biosynthesis and regulation of fatty acids in their lipid particles. Recently, some oleaginous yeasts such as R. toruloides have been found to have a unique fatty acids synthetase and other oleaginous yeasts such as A. melanogenum have a unique highly reducing polyketide synthase (HR-PKS) involved in the biosynthesis of hydroxyl fatty acids. It is necessary to further enhance lipid biosynthesis using metabolic engineering and explore new applications of fatty acids in biotechnology.

  11. YNL134C from Saccharomyces cerevisiae encodes a novel protein with aldehyde reductase activity for detoxification of furfural derived from lignocellulosic biomass.

    Science.gov (United States)

    Zhao, Xianxian; Tang, Juan; Wang, Xu; Yang, Ruoheng; Zhang, Xiaoping; Gu, Yunfu; Li, Xi; Ma, Menggen

    2015-05-01

    Furfural and 5-hydroxymethylfurfural (HMF) are the two main aldehyde compounds derived from pentoses and hexoses, respectively, during lignocellulosic biomass pretreatment. These two compounds inhibit microbial growth and interfere with subsequent alcohol fermentation. Saccharomyces cerevisiae has the in situ ability to detoxify furfural and HMF to the less toxic 2-furanmethanol (FM) and furan-2,5-dimethanol (FDM), respectively. Herein, we report that an uncharacterized gene, YNL134C, was highly up-regulated under furfural or HMF stress and Yap1p and Msn2/4p transcription factors likely controlled its up-regulated expression. Enzyme activity assays showed that YNL134C is an NADH-dependent aldehyde reductase, which plays a role in detoxification of furfural to FM. However, no NADH- or NADPH-dependent enzyme activity was observed for detoxification of HMF to FDM. This enzyme did not catalyse the reverse reaction of FM to furfural or FDM to HMF. Further studies showed that YNL134C is a broad-substrate aldehyde reductase, which can reduce multiple aldehydes to their corresponding alcohols. Although YNL134C is grouped into the quinone oxidoreductase family, no quinone reductase activity was observed using 1,2-naphthoquinone or 9,10-phenanthrenequinone as a substrate, and phylogenetic analysis indicates that it is genetically distant to quinone reductases. Proteins similar to YNL134C in sequence from S. cerevisiae and other microorganisms were phylogenetically analysed. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Improving ethanol yield in acetate-reducing Saccharomyces cerevisiae by cofactor engineering of 6-phosphogluconate dehydrogenase and deletion of ALD6

    NARCIS (Netherlands)

    Papapetridis, I.; van Dijk, M.; Dobbe, Arthur P A; Metz, B.; Pronk, J.T.; van Maris, A.J.A.

    2016-01-01

    Background: Acetic acid, an inhibitor of sugar fermentation by yeast, is invariably present in lignocellulosic hydrolysates which are used or considered as feedstocks for yeast-based bioethanol production. Saccharomyces cerevisiae strains have been constructed, in which anaerobic reduction of

  13. By-products resulting from lignocellulose pretreatment and their inhibitory effect on fermentations for (bio)chemicals and fuels

    NARCIS (Netherlands)

    Pol, van der E.C.; Bakker, R.R.; Baets, P.; Eggink, G.

    2014-01-01

    Lignocellulose might become an important feedstock for the future development of the biobased economy. Although up to 75 % of the lignocellulose dry weight consists of sugar, it is present in a polymerized state and cannot be used directly in most fermentation processes for the production of

  14. Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass

    Science.gov (United States)

    Maddi, Balakrishna

    Pyrolysis is a processing technique involving thermal degradation of biomass in the absence of oxygen. The bio-oils obtained following the condensation of the pyrolysis vapors form a convenient starting point for valorizing the major components of lignocellulosic as well as algal biomass feed stocks for the production of fuels and value-added chemicals. Pyrolysis can be implemented on whole biomass or on residues left behind following standard fractionation methods. Microalgae and oil seeds predominantly consist of protein, carbohydrate and triglycerides, whereas lignocellulose is composed of carbohydrates (cellulose and hemicellulose) and lignin. The differences in the major components of these two types of biomass will necessitate different pyrolysis strategies to derive the optimal benefits from the resulting bio-oils. In this thesis, novel pyrolysis strategies were developed that enable efficient utilization of the bio-oils (and/or their vapors) from lignocellulose, algae, as well as oil seed feed stocks. With lignocellulosic feed stocks, pyrolysis of whole biomass as well as the lignin residue left behind following well-established pretreatment and saccharification (i.e., depolymerization of cellulose and hemicellulose to their monomeric-sugars) of the biomass was studied with and without catalysts. Following this, pyrolysis of (lipid-deficient) algae and lignocellulosic feed stocks, under similar reactor conditions, was performed for comparison of product (bio-oil, gas and bio-char) yields and composition. In spite of major differences in component bio-polymers, feedstock properties relevant to thermo-chemical conversions, such as overall C, H and O-content, C/O and H/C molar ratio as well as calorific values, were found to be similar for algae and lignocellulosic material. Bio-oil yields from algae and some lignocellulosic materials were similar; however, algal bio-oils were compositionally different and contained several N-compounds (most likely from

  15. Yeast for virus research

    Science.gov (United States)

    Zhao, Richard Yuqi

    2017-01-01

    Budding yeast (Saccharomyces cerevisiae) and fission yeast (Schizosaccharomyces pombe) are two popular model organisms for virus research. They are natural hosts for viruses as they carry their own indigenous viruses. Both yeasts have been used for studies of plant, animal and human viruses. Many positive sense (+) RNA viruses and some DNA viruses replicate with various levels in yeasts, thus allowing study of those viral activities during viral life cycle. Yeasts are single cell eukaryotic organisms. Hence, many of the fundamental cellular functions such as cell cycle regulation or programed cell death are highly conserved from yeasts to higher eukaryotes. Therefore, they are particularly suited to study the impact of those viral activities on related cellular activities during virus-host interactions. Yeasts present many unique advantages in virus research over high eukaryotes. Yeast cells are easy to maintain in the laboratory with relative short doubling time. They are non-biohazardous, genetically amendable with small genomes that permit genome-wide analysis of virologic and cellular functions. In this review, similarities and differences of these two yeasts are described. Studies of virologic activities such as viral translation, viral replication and genome-wide study of virus-cell interactions in yeasts are highlighted. Impacts of viral proteins on basic cellular functions such as cell cycle regulation and programed cell death are discussed. Potential applications of using yeasts as hosts to carry out functional analysis of small viral genome and to develop high throughput drug screening platform for the discovery of antiviral drugs are presented. PMID:29082230

  16. Precultivation of Bacillus coagulans DSM2314 in the presence of furfural decreases inhibitory effects of lignocellulosic by-products during l(+)-lactic acid fermentation

    NARCIS (Netherlands)

    Pol, van der Edwin; Springer, Jan; Vriesendorp, Bastienne; Weusthuis, Ruud; Eggink, Gerrit

    2016-01-01

    By-products resulting from thermo-chemical pretreatment of lignocellulose can inhibit fermentation of lignocellulosic sugars to lactic acid. Furfural is such a by-product, which is formed during acid pretreatment of lignocellulose. pH-controlled fermentations with 1 L starting volume, containing

  17. Growth of oleaginous Rhodotorula glutinis in an internal-loop airlift bioreactor by using lignocellulosic biomass hydrolysate as the carbon source.

    Science.gov (United States)

    Yen, Hong-Wei; Chang, Jung-Tzu

    2015-05-01

    The conversion of abundant lignocellulosic biomass (LCB) to valuable compounds has become a very attractive idea recently. This study successfully used LCB (rice straw) hydrolysate as a carbon source for the cultivation of oleaginous yeast-Rhodotorula glutinis in an airlift bioreactor. The lipid content of 34.3 ± 0.6% was obtained in an airlift batch with 60 g reducing sugars/L of LCB hydrolysate at a 2 vvm aeration rate. While using LCB hydrolysate as the carbon source, oleic acid (C18:1) and linoleic acid (C18:2) were the predominant fatty acids of the microbial lipids. Using LCB hydrolysate in the airlift bioreactor at 2 vvm achieved the highest cell mass growth as compared to the agitation tank. Despite the low lipid content of the batch using LCB hydrolysate, this low cost feedstock has the potential of being adopted for the production of β-carotene instead of lipid accumulation in the airlift bioreactor for the cultivation of R. glutinis. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. [Degradation of lignocellulose in the corn straw by Bacillus amyloliquefaciens MN-8].

    Science.gov (United States)

    Li, Hong-ya; Li, Shu-na; Wang, Shu-xiang; Wang, Quan; Xue, Yin-yin; Zhu, Bao-cheng

    2015-05-01

    Microbial degradation of lignocellulose is one of the key problems that need to be solved urgently in the process of utilizing biomass resource. Bacillus amyloliquefaciens MN-8 is our previously isolated bacterium capable of degrading lignin. To determine the capability of strain MN-8 to degrade lignocellulose of corn straw, B. amyloliquefaciens MN-8 was inoculated and fermented with solid-state corn straw powder-MSM culture medium. The changes in the enzyme activity and degradation products of lignocellulose were monitored in the process of fermentation using the FTIR and GC/MS. The results showed that B. amyloliquefaciens MN-8 could produce lignin peroxidase, manganese peroxidase, cellulase and hemicellulase enzymes. The activities of all these enzymes reached the peak after being incubated for 10-16 days, and the highest enzyme activities were 55.0, 16.7, 45.4 and 60.5 U · g(-1), respectively. After 24 d of incubation, the degradation percentages of lignin, cellulose and hemicellulose were up to 42.9%, 40.6% and 27.1%, respectively. The spectroscopic data by FTIR indicated that the intensities of characteristic absorption peaks of lignin, cellulose and hemicellulose of the corn straw were decreased, indicating that the lignocellulose was degraded partly after being fermented by B. amyloliquefaciens MN-8. GC/MS analysis also demonstrated that strain MN-8 could degrade lignocellulose efficiently. It could depolymerize lignin into some monomeric compounds with retention of phenylpropane structure unit, such as amphetamine, benzene acetone and benzene propanoic acids, by the rupture of β-O-4 bond connected between lignin monomer, and it further oxidized some monomer compounds into Cα carbonyl compounds, such as 2-amino-1-benzeneacetone and 4-hydroxy-3,5-dimethoxy-acetophenone. The GC/MS analysis of the degradation products of cellulose and hemicellulose showed that there were not only monosaccharide compounds, such as glucose, mannose and galactose, but also some

  19. Enzymatic hydrolyzing performance of Acremonium cellulolyticus and Trichoderma reesei against three lignocellulosic materials

    Directory of Open Access Journals (Sweden)

    Murakami Katsuji

    2009-10-01

    Full Text Available Abstract Background Bioethanol isolated from lignocellulosic biomass represents one of the most promising renewable and carbon neutral alternative liquid fuel sources. Enzymatic saccharification using cellulase has proven to be a useful method in the production of bioethanol. The filamentous fungi Acremonium cellulolyticus and Trichoderma reesei are known to be potential cellulase producers. In this study, we aimed to reveal the advantages and disadvantages of the cellulase enzymes derived from these fungi. Results We compared A. cellulolyticus and T. reesei cellulase activity against the three lignocellulosic materials: eucalyptus, Douglas fir and rice straw. Saccharification analysis using the supernatant from each culture demonstrated that the enzyme mixture derived from A. cellulolyticus exhibited 2-fold and 16-fold increases in Filter Paper enzyme and β-glucosidase specific activities, respectively, compared with that derived from T. reesei. In addition, culture supernatant from A. cellulolyticus produced glucose more rapidly from the lignocellulosic materials. Meanwhile, culture supernatant derived from T. reesei exhibited a 2-fold higher xylan-hydrolyzing activity and produced more xylose from eucalyptus (72% yield and rice straw (43% yield. Although the commercial enzymes Acremonium cellulase (derived from A. cellulolyticus, Meiji Seika Co. demonstrated a slightly lower cellulase specific activity than Accellerase 1000 (derived from T. reesei, Genencor, the glucose yield (over 65% from lignocellulosic materials by Acremonium cellulase was higher than that of Accellerase 1000 (less than 60%. In addition, the mannan-hydrolyzing activity of Acremonium cellulase was 16-fold higher than that of Accellerase 1000, and the conversion of mannan to mannobiose and mannose by Acremonium cellulase was more efficient. Conclusion We investigated the hydrolysis of lignocellulosic materials by cellulase derived from two types of filamentous fungi. We

  20. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Suominen, Pirkko; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric

    2013-02-12

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. A yeast strain engineered to metabolize arabinose through a novel pathway is also disclosed. Methods of producing ethanol include utilizing these modified yeast strains.

  1. Acrolein-detoxifying isozymes of glutathione transferase in plants.

    Science.gov (United States)

    Mano, Jun'ichi; Ishibashi, Asami; Muneuchi, Hitoshi; Morita, Chihiro; Sakai, Hiroki; Biswas, Md Sanaullah; Koeduka, Takao; Kitajima, Sakihito

    2017-02-01

    Acrolein is a lipid-derived highly reactive aldehyde, mediating oxidative signal and damage in plants. We found acrolein-scavenging glutathione transferase activity in plants and purified a low K M isozyme from spinach. Various environmental stressors on plants cause the generation of acrolein, a highly toxic aldehyde produced from lipid peroxides, via the promotion of the formation of reactive oxygen species, which oxidize membrane lipids. In mammals, acrolein is scavenged by glutathione transferase (GST; EC 2.5.1.18) isozymes of Alpha, Pi, and Mu classes, but plants lack these GST classes. We detected the acrolein-scavenging GST activity in four species of plants, and purified an isozyme showing this activity from spinach (Spinacia oleracea L.) leaves. The isozyme (GST-Acr), obtained after an affinity chromatography and two ion exchange chromatography steps, showed the K M value for acrolein 93 μM, the smallest value known for acrolein-detoxifying enzymes in plants. Peptide sequence homology search revealed that GST-Acr belongs to the GST Tau, a plant-specific class. The Arabidopsis thaliana GST Tau19, which has the closest sequence similar to spinach GST-Acr, also showed a high catalytic efficiency for acrolein. These results suggest that GST plays as a scavenger for acrolein in plants.

  2. Perspectives for the production of bioethanol from lignocellulosic materials

    International Nuclear Information System (INIS)

    Petrova, Petia; Ivanova, Viara

    2010-01-01

    The most common renewable fuel today and suitable alternative to replace fossil fuels is ethanol that can be blended with petrol or used as neat alcohol in engines. Ethanol is currently produced from sugar (Brazil) or grain (starch, USA). However, this raw material base will not be sufficient because the increasing demand for fuel ethanol and the lower than expected reduction of greenhouse gases. An alternative is the production of bioethanol from agroindustrial wastes containing abundant cellulose fibers and carbohydrates such as grape pomace, sugar beet pomace, barley and rice straw, corncobs, sunflower stalks and heads, cotton waste, brewer's spent grain, forest residues etc. Lignocellulosic raw materials and agroindustrial wastes minimize the potential conflict between land use for food (and feed) production and energy feedstock production. This review summarizes recent developments in the bioconversion processes, the new technologies required and the advances achieved in recent years to bring agricultural feedstock and lignocellulosic ethanol towards industrial production.

  3. Separation of lignocelluloses from spent liquor of NSSC pulping process via adsorption.

    Science.gov (United States)

    Dashtban, Mehdi; Gilbert, Allan; Fatehi, Pedram

    2014-04-01

    Hemicelluloses and lignin present in the spent liquor (SL) of neutral sulfite semichemical (NSSC) pulping process can potentially be converted into value-added products such as furfural, hydroxymethylfurfural, levulinic acid, phenols and adhesives. However, the direct conversion of hemicelluloses and lignin of SL into value-added products is uneconomical due to the dilute nature of the SL. To have a feasible downstream process for utilizing lignocelluloses of SL, the lignocelluloses should initially be separated from the SL. In this study, an adsorption process (via applying activated carbon) was considered for isolating the dissolved lignin and hemicelluloses from the SL of an NSSC pulping process. Under the optimal conditions of pH, SL/AC weight ratio, time and temperature of 5.7, 30, 360 min and 30 °C, the maximum lignin and hemicellulose adsorptions were 0.33 and 0.25 g/g on AC. The chemical oxygen demand (COD) and turbidity of the SL were decreased by 11% and 39%, respectively, as a result of lignocellulose adsorption on AC. Also, the incineration behavior of the SL-treated AC was studied with a thermo-gravimetric analysis (TGA). Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Evaluation of Alkali-Pretreated Soybean Straw for Lignocellulosic Bioethanol Production

    Directory of Open Access Journals (Sweden)

    Seonghun Kim

    2018-01-01

    Full Text Available Soybean straw is a renewable resource in agricultural residues that can be used for lignocellulosic bioethanol production. To enhance enzymatic digestibility and fermentability, the biomass was prepared with an alkali-thermal pretreatment (sodium hydroxide, 121°C, 60 min. The delignification yield was 34.1~53%, in proportion to the amount of sodium hydroxide, from 0.5 to 3.0 M. The lignin and hemicellulose contents of the pretreated biomass were reduced by the pretreatment process, whereas the proportion of cellulose was increased. Under optimal condition, the pretreated biomass consisted of 74.0±0.1% cellulose, 10.3±0.1% hemicellulose, and 10.1±0.6% lignin. During enzymatic saccharification using Cellic® CTec2 cellulase, 10% (w/v of pretreated soybean straw was hydrolyzed completely and converted to 67.3±2.1 g/L glucose and 9.4±0.5 g/L xylose with a 90.9% yield efficiency. Simultaneous saccharification and fermentation of the pretreated biomass by Saccharomyces cerevisiae W303-1A produced 30.5±1.2 g/L ethanol in 0.5 L fermented medium containing 10% (w/v pretreated biomass after 72 h. The ethanol productivity was 0.305 g ethanol/g dry biomass and 0.45 g ethanol/g glucose after fermentation, with a low concentration of organic acid metabolites. Also, 82% of fermentable sugar was used by the yeast for ethanol fermentation. These results show that the combination of alkaline pretreatment and biomass hydrolysate is useful for enhancing bioethanol productivity using delignified soybean straw.

  5. Analysis of the potential for biodiesel production in Cuba of lignocellulosic biomass

    International Nuclear Information System (INIS)

    Alcalá-Galiano Morell, Diana Deisy; Cujilema Qutio, Mario C.; Leon Revelo, Gualberto; Márquez Peñamaría, Grety; Morell Nápoles, Giselle; Ramos Sánchez, Luis B.; Fikers, Patrick

    2015-01-01

    The use of lignocellulosic biomass available in the country is a significant source of renewable energy (RES) to the planned development in the coming years. The relevance of the work in this direction has been endorsed in the new policy on FRE was approved last June. Among the various chemical routes to take to get energy biofuels of great importance it stands to meet growing demand in the transport sector. In this paper the strategy of research and technological development is being followed at the University of Camaguey to create conditions for pilot production of bioethanol and biodiesel lignocellulosic scale is discussed. (full text)

  6. Assessing the effect of selection with deltamethrin on biological parameters and detoxifying enzymes in Aedes aegypti (L.).

    Science.gov (United States)

    Alvarez-Gonzalez, Leslie C; Briceño, Arelis; Ponce-Garcia, Gustavo; Villanueva-Segura, O Karina; Davila-Barboza, Jesus A; Lopez-Monroy, Beatriz; Gutierrez-Rodriguez, Selene M; Contreras-Perera, Yamili; Rodriguez-Sanchez, Iram P; Flores, Adriana E

    2017-11-01

    Resistance to insecticides through one or several mechanisms has a cost for an insect in various parameters of its biological cycle. The present study evaluated the effect of deltamethrin on detoxifying enzymes and biological parameters in a population of Aedes aegypti selected for 15 generations. The enzyme activities of alpha- and beta-esterases, mixed-function oxidases and glutathione-S-transferases were determined during selection, along with biological parameters. Overexpression of mixed-function oxidases as a mechanism of metabolic resistance to deltamethrin was found. There were decreases in percentages of eggs hatching, pupation and age-specific survival and in total survival at the end of the selection (F 16 ). Although age-specific fecundity was not affected by selection with deltamethrin, total fertility, together with lower survival, significantly affected gross reproduction rate, gradually decreasing due to deltamethrin selection. Similarly, net reproductive rate and intrinsic growth rate were affected by selection. Alterations in life parameters could be due to the accumulation of noxious effects or deleterious genes related to detoxifying enzymes, specifically those coding for mixed-function oxidases, along with the presence of recessive alleles of the V1016I and F1534C mutations, associating deltamethrin resistance with fitness cost in Ae. aegypti. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. SINGLE-CELL PROTEIN-QUALITY PRODUCED FROM LIGNOCELLULOSIC MATERIALS BY THE ASCOMYCETE CHRYSONILIA-SITOPHILA (TFB-27441 STRAIN)

    OpenAIRE

    DURAN, N; RODRIGUEZ, J; CAMPOS, V; FERRAZ, A; REYES, JL; AMAYAFARFAN, J; ESPOSITO, E; ADAO, F; BAEZA, J; FREER, J; URIZAR, S

    1994-01-01

    Data are presented for amino acid contents of fifteen carbohydrates, lignocellulosic materials, including olive milling waste water. The selected substrate were: glucose, cellobiose, saccharose, microcrystalline cellulose, tannin, phlobaphene, bark, lignocellulose residue, sugar residue from organosolv process, rice hull, irradiated rice hull, orange bagasse, alpechin (5%), alpechin (10%) and irradiated alpechin (10%). Ratios of some amino acids of nutritional significance in conventional pro...

  8. Utilization of selected biorenewable resources: solubilization of lignocellulosics and conjugation of soybean oil

    Energy Technology Data Exchange (ETDEWEB)

    Oshel, Reed E. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    In recent years, concern has risen over the use of fossil fuels due to their contribution to global warming, and to our dependence on imports of petroleum from nations that could pose a threat to national security. As a result, it has become increasingly important to develop technologies to replace fossil fuel based products with biorenewable alternatives. In this thesis nearly quantitative solubilization of lignocellulosic materials using phosphite esters has been realized, and is presented as a potential pretreatment for production of fermentable sugars for use in manufacturing commodity chemicals, specifically ethanol. Water solubilization of lignocellulosics using phosphite esters will enhance digestibility by disrupting the lignocellulose structure, changing cellulose morphology, and cleaving some glycosidic bonds. In a second project, soybean oil, which contains un-conjugated polyunsaturated fatty acid esters, is isomerized into oil containing conjugated polyunsaturates. The process is carried out under photochemical conditions using iodine as a catalyst in a hexanes solution to achieve 99% conjugation. The resulting conjugated soybean oil is demonstrated to have enhanced drying properties for use in alkyd resins.

  9. New approaches for improving the production of the 1st and 2nd generation ethanol by yeast.

    Science.gov (United States)

    Kurylenko, Olena; Semkiv, Marta; Ruchala, Justyna; Hryniv, Orest; Kshanovska, Barbara; Abbas, Charles; Dmytruk, Kostyantyn; Sibirny, Andriy

    2016-01-01

    Increase in the production of 1st generation ethanol from glucose is possible by the reduction in the production of ethanol co-products, especially biomass. We have developed a method to reduce biomass accumulation of Saccharomyces cerevisiae by the manipulation of the intracellular ATP level due to overexpression of genes of alkaline phosphatase, apyrase or enzymes involved in futile cycles. The strains constructed accumulated up to 10% more ethanol on a cornmeal hydrolysate medium. Similar increase in ethanol accumulation was observed in the mutants resistant to the toxic inhibitors of glycolysis like 3-bromopyruvate and others. Substantial increase in fuel ethanol production will be obtained by the development of new strains of yeasts that ferment sugars of the abundant lignocellulosic feedstocks, especially xylose, a pentose sugar. We have found that xylose can be fermented under elevated temperatures by the thermotolerant yeast, Hansenula polymorpha. We combined protein engineering of the gene coding for xylose reductase (XYL1) along with overexpression of the other two genes responsible for xylose metabolism in yeast (XYL2, XYL3) and the deletion of the global transcriptional activator CAT8, with the selection of mutants defective in utilizing ethanol as a carbon source using the anticancer drug, 3-bromopyruvate. Resulted strains accumulated 20-25 times more ethanol from xylose at the elevated temperature of 45°C with up to 12.5 g L(-1) produced. Increase in ethanol yield and productivity from xylose was also achieved by overexpression of genes coding for the peroxisomal enzymes: transketolase (DAS1) and transaldolase (TAL2), and deletion of the ATG13 gene.

  10. Synchrotron-based X-ray fluorescence microscopy enables multiscale spatial visualization of ions involved in fungal lignocellulose deconstruction

    Science.gov (United States)

    Grant T. Kirker; Samuel Zelinka; Sophie-Charlotte Gleber; David Vine; Lydia Finney; Si Chen; Young Pyo Hong; Omar Uyarte; Stefan Vogt; Jody Jellison; Barry Goodell; Joseph E. Jakes

    2017-01-01

    The role of ions in the fungal decay process of lignocellulose biomaterials, and more broadly fungal metabolism, has implications for diverse research disciplines ranging from plant pathology and forest ecology, to carbon sequestration. Despite the importance of ions in fungal decay mechanisms, the spatial distribution and quantification of ions in lignocellulosic cell...

  11. Lignocellulosic biorefinery as a model for sustainable development of biofuels and value added products.

    Science.gov (United States)

    De Bhowmick, Goldy; Sarmah, Ajit K; Sen, Ramkrishna

    2018-01-01

    A constant shift of society's dependence from petroleum-based energy resources towards renewable biomass-based has been the key to tackle the greenhouse gas emissions. Effective use of biomass feedstock, particularly lignocellulosic, has gained worldwide attention lately. Lignocellulosic biomass as a potent bioresource, however, cannot be a sustainable alternative if the production cost is too high and/ or the availability is limited. Recycling the lignocellulosic biomass from various sources into value added products such as bio-oil, biochar or other biobased chemicals in a bio-refinery model is a sensible idea. Combination of integrated conversion techniques along with process integration is suggested as a sustainable approach. Introducing 'series concept' accompanying intermittent dark/photo fermentation with co-cultivation of microalgae is conceptualised. While the cost of downstream processing for a single type of feedstock would be high, combining different feedstocks and integrating them in a bio-refinery model would lessen the production cost and reduce CO 2 emission. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Reactivity of long chain alkylamines to lignin moieties: implications on hydrophobicity of lignocellulose materials.

    Science.gov (United States)

    Kudanga, Tukayi; Prasetyo, Endry Nugroho; Sipilä, Jussi; Guebitz, Georg M; Nyanhongo, Gibson S

    2010-08-20

    Enzymatic processes provide new perspectives for modification of lignocellulose materials. In the current study, laccase catalyzed coupling of long chain alkylamines to lignin model molecules and lignocellulose was investigated. Up to two molecules of dodecylamine (DA) and dihexylamine (DHA) were successfully coupled with lignin monomers (guaiacol, catechol and ferulic acid) while coupling onto complex lignin model compounds (syringylglycerol beta-guaiacyl ether, guaiacylglycerol beta-guaiacyl ether and dibenzodioxocin) yielded 1:1 coupling products. Surface analysis of beech veneers enzymatically grafted with DA showed an increase in nitrogen content of 3.18% compared to 0.71% in laccase only treated controls while the O/C ratio decreased from 0.52 to 0.46. Concomitantly the grafting of DHA or DA onto beech veneers resulted in a 53.8% and 84.2% increase in hydrophobicity, respectively when compared to simple adsorption. Therefore, laccase-mediated grafting of long chain alkylamines onto lignocellulose materials can be potentially exploited for improving their hydrophobicity. Copyright 2010 Elsevier B.V. All rights reserved.

  13. Factors governing dissolution process of lignocellulosic biomass in ionic liquid: current status, overview and challenges.

    Science.gov (United States)

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2015-02-01

    The utilisation of non-feed lignocellulosic biomass as a source of renewable bio-energy and synthesis of fine chemical products is necessary for the sustainable development. The methods for the dissolution of lignocellulosic biomass in conventional solvents are complex and tedious due to the complex chemical ultra-structure of biomass. In view of this, recent developments for the use of ionic liquid solvent (IL) has received great attention, as ILs can solubilise such complex biomass and thus provides industrial scale-up potential. In this review, we have discussed the state-of-art for the dissolution of lignocellulosic material in representative ILs. Furthermore, various process parameters and their influence for biomass dissolution were reviewed. In addition to this, overview of challenges and opportunities related to this interesting area is presented. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Lignocellulosic ethanol production from woody biomass: The impact of facility siting on competitiveness

    International Nuclear Information System (INIS)

    Stephen, James D.; Mabee, Warren E.; Saddler, Jack N.

    2013-01-01

    Just as temperate region pulp and paper companies need to compete with Brazilian eucalyptus pulp producers, lignocellulosic biofuel producers in North America and Europe, in the absence of protectionist trade policies, will need to be competitive with tropical and sub-tropical biofuel producers. This work sought to determine the impact of lignocellulosic ethanol biorefinery siting on economic performance and minimum ethanol selling price (MESP) for both east and west coast North American fuel markets. Facility sites included the pine-dominated Pacific Northwest Interior, the mixed deciduous forest of Ontario and New York, and the Brazilian state of Espírito Santo. Feedstock scenarios included both plantation (poplar, willow, and eucalyptus, respectively) and managed forest harvest. Site specific variables in the techno-economic model included delivered feedstock cost, ethanol delivery cost, cost of capital, construction cost, labour cost, electricity revenues (and co-product credits), and taxes, insurance, and permits. Despite the long shipping distance from Brazil to North American east and west coast markets, the MESP for Brazilian-produced eucalyptus lignocellulosic ethanol, modelled at $0.74 L −1 , was notably lower than that of all North American-produced cases at $0.83–1.02 L −1 . - Highlights: • Lignocellulosic ethanol production costs vary notably by region. • Feedstock cost is the primary site-specific production cost variable. • Woody feedstocks in North America have a higher cost than those in Brazil. • Use of Brazilian eucalyptus resulted in the lowest MESP for considered feedstocks. • MESP ranged from −1 to >$1.00 L −1

  15. Rich biotin content in lignocellulose biomass plays the key role in determining cellulosic glutamic acid accumulation by Corynebacterium glutamicum.

    Science.gov (United States)

    Wen, Jingbai; Xiao, Yanqiu; Liu, Ting; Gao, Qiuqiang; Bao, Jie

    2018-01-01

    Lignocellulose is one of the most promising alternative feedstocks for glutamic acid production as commodity building block chemical, but the efforts by the dominant industrial fermentation strain Corynebacterium glutamicum failed for accumulating glutamic acid using lignocellulose feedstock. We identified the existence of surprisingly high biotin concentration in corn stover hydrolysate as the determining factor for the failure of glutamic acid accumulation by Corynebacterium glutamicum . Under excessive biotin content, induction by penicillin resulted in 41.7 ± 0.1 g/L of glutamic acid with the yield of 0.50 g glutamic acid/g glucose. Our further investigation revealed that corn stover contained 353 ± 16 μg of biotin per kg dry solids, approximately one order of magnitude greater than the biotin in corn grain. Most of the biotin remained stable during the biorefining chain and the rich biotin content in corn stover hydrolysate almost completely blocked the glutamic acid accumulation. This rich biotin existence was found to be a common phenomenon in the wide range of lignocellulose biomass and this may be the key reason why the previous studies failed in cellulosic glutamic acid fermentation from lignocellulose biomass. The extended recording of the complete members of all eight vitamin B compounds in lignocellulose biomass further reveals that the major vitamin B members were also under the high concentration levels even after harsh pretreatment. The high content of biotin in wide range of lignocellulose biomass feedstocks and the corresponding hydrolysates was discovered and it was found to be the key factor in determining the cellulosic glutamic acid accumulation. The highly reserved biotin and the high content of their other vitamin B compounds in biorefining process might act as the potential nutrients to biorefining fermentations. This study creates a new insight that lignocellulose biorefining not only generates inhibitors, but also keeps nutrients

  16. Fungal treated lignocellulosic biomass as ruminant feed ingredient: A review

    NARCIS (Netherlands)

    Kuijk, van S.J.A.; Sonnenberg, A.S.M.; Baars, J.J.P.; Hendriks, W.H.; Cone, J.W.

    2015-01-01

    In ruminant nutrition, there is an increasing interest for ingredients that do not compete with human nutrition. Ruminants are specialists in digesting carbohydrates in plant cell walls; therefore lignocellulosic biomass has potential in ruminant nutrition. The presence of lignin in biomass,

  17. Genomic mechanisms of stress tolerance for the industrial yeast Saccharomyces cerevisiae against the major chemical classes of inhibitors derived from lignocellulosic biomass conversion

    Science.gov (United States)

    Scientists at ARS developed tolerant industrial yeast that is able to reduce major chemical classes of inhibitors into less toxic or none toxic compounds while producing ethanol. Using genomic studies, we defined mechanisms of in situ detoxification involved in novel gene functions, vital cofactor r...

  18. Comparison of lignocellulose composition in four major species of ...

    African Journals Online (AJOL)

    By principal component analysis (PCA), the components ADF and cellulose were the PC1 that were considered the foremost for the evaluation and selection of resource in the four species. The conclusions show that lignocellulose composition contents of Miscanthus culms were different. M. floridulus was more fit to ethanol ...

  19. Value-added biotransformation of cellulosic sugars by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Lane, Stephan; Dong, Jia; Jin, Yong-Su

    2018-07-01

    The substantial research efforts into lignocellulosic biofuels have generated an abundance of valuable knowledge and technologies for metabolic engineering. In particular, these investments have led to a vast growth in proficiency of engineering the yeast Saccharomyces cerevisiae for consuming lignocellulosic sugars, enabling the simultaneous assimilation of multiple carbon sources, and producing a large variety of value-added products by introduction of heterologous metabolic pathways. While microbial conversion of cellulosic sugars into large-volume low-value biofuels is not currently economically feasible, there may still be opportunities to produce other value-added chemicals as regulation of cellulosic sugar metabolism is quite different from glucose metabolism. This review summarizes these recent advances with an emphasis on employing engineered yeast for the bioconversion of lignocellulosic sugars into a variety of non-ethanol value-added products. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Effect of dietary lignocellulose on ileal and total tract digestibility of fat and fatty acids in broiler chickens.

    Science.gov (United States)

    Bogusławska-Tryk, M; Piotrowska, A; Szymeczko, R; Burlikowska, K

    2016-12-01

    The study was conducted to determine the effect of a lignocellulose supplemented diet on apparent ileal and total tract digestibility of fat and fatty acids (FA) in broiler chickens. A total of 48 21-day-old male Ross 308 chickens were divided into four treatment groups (n = 12) with six replicates per treatment. From 21 to 42 days of age, the broilers were fed experimental diets varied in the amount of lignocellulose: 0%, 0.25%, 0.5% and 1%. Total excreta were gathered during the last 3 days of the feeding trial and digesta was collected from the ileum at 42 days of the bird age. Digestibility was determined by the indicator method. The ether extract content in diet/digesta/excreta was determined by the gravimetric method, and fatty acid methyl esters were analysed by gas chromatography-mass spectrometry. Fat digestibility measured to the end of the small intestine and in the whole gastrointestinal tract in birds was high and exceeded 90% and 87% respectively. Addition of lignocellulose (1%) increased (p digestibility but had no significant effect on total tract fat digestion. Absorption of total fatty acids (TFA) as well as myristic (C14:0), palmitoleic (C16:1) and α-linolenic (C18:3n-3) acids, estimated by both methods, was significantly higher in birds fed the diets supplemented with lignocellulose, especially at a dose of 1%. Total tract absorption of some dietary polyunsaturated fatty acids (PUFA) (C20:2, C20:4n-6) was significantly lower from diet supplemented with 0.5% and 0.25% lignocellulose. There was observed a decrease in apparent digestibility of fat and most examined fatty acids, when measured between terminal ileum and total gastrointestinal tract. The results suggest that lignocellulose can affect digestion and FA absorption in broilers but, as the effect of lignocellulose was not studied previously, further investigations are necessary to confirm the results of the present experiment. Journal of Animal Physiology and Animal Nutrition © 2016

  1. pH-Induced Lignin Surface Modification to Reduce Nonspecific Cellulase Binding and Enhance Enzymatic Saccharification of Lignocelluloses

    Science.gov (United States)

    Hongming Lou; J.Y. Zhu; Tian Qing Lan; Huranran Lai; Xueqing Qiu

    2013-01-01

    We studied the mechanism of the significant enhancement in the enzymatic saccharification of lignocelluloses at an elevated pH of 5.5–6.0. Four lignin residues with different sulfonic acid contents were isolated from enzymatic hydrolysis of lodgepole pine pretreated by either dilute acid (DA) or sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL...

  2. Examination of lignocellulosic fibers for chemical, thermal, and separations properties: Addressing thermo-chemical stability issues

    Science.gov (United States)

    Johnson, Carter David

    Natural fiber-plastic composites incorporate thermoplastic resins with fibrous plant-based materials, sometimes referred to as biomass. Pine wood mill waste has been the traditional source of natural fibrous feedstock. In anticipation of a waste wood shortage other fibrous biomass materials are being investigated as potential supplements or replacements. Perennial grasses, agricultural wastes, and woody biomass are among the potential source materials. As these feedstocks share the basic chemical building blocks; cellulose, hemicellulose, and lignin, they are collectively called lignocellulosics. Initial investigation of a number of lignocellulosic materials, applied to fiber-plastic composite processing and material testing, resulted in varied results, particularly response to processing conditions. Less thermally stable lignocellulosic filler materials were physically changed in observable ways: darkened color and odor. The effect of biomass materials' chemical composition on thermal stability was investigated an experiment involving determination of the chemical composition of seven lignocellulosics: corn hull, corn stover, fescue, pine, soy hull, soy stover, and switchgrass. These materials were also evaluated for thermal stability by thermogravimetric analysis. The results of these determinations indicated that both chemical composition and pretreatment of lignocellulosic materials can have an effect on their thermal stability. A second study was performed to investigate what effect different pretreatment systems have on hybrid poplar, pine, and switchgrass. These materials were treated with hot water, ethanol, and a 2:1 benzene/ethanol mixture for extraction times of: 1, 3, 6, 12, and 24 hours. This factorial experiment demonstrated that both extraction time and medium have an effect on the weight percent of extractives removed from all three material types. The extracted materials generated in the above study were then subjected to an evaluation of thermal

  3. Yeast Flocculation—Sedimentation and Flotation

    Directory of Open Access Journals (Sweden)

    Graham G. Stewart

    2018-04-01

    Full Text Available Unlike most fermentation alcohol beverage production processes, brewers recycle their yeast. This is achieved by employing a yeast culture’s: flocculation, adhesion, sedimentation, flotation, and cropping characteristics. As a consequence of yeast recycling, the quality of the cropped yeast culture’s characteristics is critical. However, the other major function of brewer’s yeast is to metabolise wort into ethanol, carbon dioxide, glycerol, and other fermentation products, many of which contribute to beer’s overall flavour characteristics. This review will only focus on brewer’s yeast flocculation characteristics.

  4. Lignocellulosics to ethanol: The future of the chemical and energy ...

    African Journals Online (AJOL)

    Energy and environmental issues are among the major concerns facing the global community today. Biofuel technology is now globally embraced as the promising technology to replace fossil fuels. Lignocellulosic waste biomass from forestry, agriculture and municipal sources are abundant, inexpensive and potential ...

  5. Yeast cell differentiation: Lessons from pathogenic and non-pathogenic yeasts.

    Science.gov (United States)

    Palková, Zdena; Váchová, Libuše

    2016-09-01

    Yeasts, historically considered to be single-cell organisms, are able to activate different differentiation processes. Individual yeast cells can change their life-styles by processes of phenotypic switching such as the switch from yeast-shaped cells to filamentous cells (pseudohyphae or true hyphae) and the transition among opaque, white and gray cell-types. Yeasts can also create organized multicellular structures such as colonies and biofilms, and the latter are often observed as contaminants on surfaces in industry and medical care and are formed during infections of the human body. Multicellular structures are formed mostly of stationary-phase or slow-growing cells that diversify into specific cell subpopulations that have unique metabolic properties and can fulfill specific tasks. In addition to the development of multiple protective mechanisms, processes of metabolic reprogramming that reflect a changed environment help differentiated individual cells and/or community cell constituents to survive harmful environmental attacks and/or to escape the host immune system. This review aims to provide an overview of differentiation processes so far identified in individual yeast cells as well as in multicellular communities of yeast pathogens of the Candida and Cryptococcus spp. and the Candida albicans close relative, Saccharomyces cerevisiae. Molecular mechanisms and extracellular signals potentially involved in differentiation processes are also briefly mentioned. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. L-arabinose fermenting yeast

    Science.gov (United States)

    Zhang, Min; Singh, Arjun; Knoshaug, Eric; Franden, Mary Ann; Jarvis, Eric; Suominen, Pirkko

    2010-12-07

    An L-arabinose utilizing yeast strain is provided for the production of ethanol by introducing and expressing bacterial araA, araB and araD genes. L-arabinose transporters are also introduced into the yeast to enhance the uptake of arabinose. The yeast carries additional genomic mutations enabling it to consume L-arabinose, even as the only carbon source, and to produce ethanol. Methods of producing ethanol include utilizing these modified yeast strains. ##STR00001##

  7. Biogas Production from Lignocellulosic Biomass : Impact of pre-treatment, co-digestion, harvest time and inoculation

    OpenAIRE

    LI, Chao

    2017-01-01

    Biogas or methane production through anaerobic digestion (AD) is gaining increasing attention worldwide due to concerns over global warming, energy security and the need for sustainable waste management. AD of lignocellulosic biomass is one facet that is highly appreciated since the conflict over biomass for food/feed or energy can be avoided. As a result the need for non-food based lignocellulosic biomass feedstock has emerged as (co-) feedstock of choice for the AD process. Despite these ad...

  8. Nitrile Metabolizing Yeasts

    Science.gov (United States)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

  9. How does cellulosome composition influence deconstruction of lignocellulosic substrates in Clostridium (Ruminiclostridium) thermocellum DSM 1313?

    Science.gov (United States)

    Yoav, Shahar; Barak, Yoav; Shamshoum, Melina; Borovok, Ilya; Lamed, Raphael; Dassa, Bareket; Hadar, Yitzhak; Morag, Ely; Bayer, Edward A

    2017-01-01

    Bioethanol production processes involve enzymatic hydrolysis of pretreated lignocellulosic biomass into fermentable sugars. Due to the relatively high cost of enzyme production, the development of potent and cost-effective cellulolytic cocktails is critical for increasing the cost-effectiveness of bioethanol production. In this context, the multi-protein cellulolytic complex of Clostridium ( Ruminiclostridium ) thermocellum, the cellulosome, was studied here. C. thermocellum is known to assemble cellulosomes of various subunit (enzyme) compositions, in response to the available carbon source. In the current study, different carbon sources were used, and their influence on both cellulosomal composition and the resultant activity was investigated. Glucose, cellobiose, microcrystalline cellulose, alkaline-pretreated switchgrass, alkaline-pretreated corn stover, and dilute acid-pretreated corn stover were used as sole carbon sources in the growth media of C. thermocellum strain DSM 1313. The purified cellulosomes were compared for their activity on selected cellulosic substrates. Interestingly, cellulosomes derived from cells grown on lignocellulosic biomass showed no advantage in hydrolyzing the original carbon source used for their production. Instead, microcrystalline cellulose- and glucose-derived cellulosomes were equal or superior in their capacity to deconstruct lignocellulosic biomass. Mass spectrometry analysis revealed differential composition of catalytic and structural subunits (scaffoldins) in the different cellulosome samples. The most abundant catalytic subunits in all cellulosome types include Cel48S, Cel9K, Cel9Q, Cel9R, and Cel5G. Microcrystalline cellulose- and glucose-derived cellulosome samples showed higher endoglucanase-to-exoglucanase ratios and higher catalytic subunit-per-scaffoldin ratios compared to lignocellulose-derived cellulosome types. The results reported here highlight the finding that cellulosomes derived from cells grown on glucose

  10. Probiotic activity of lignocellulosic enzyme as bioactivator for rice husk degradation

    Science.gov (United States)

    Lamid, Mirni; Al-Arif, Anam; Warsito, Sunaryo Hadi

    2017-02-01

    The utilization of lignocellulosic enzyme will increase nutritional value of rice husk. Cellulase consists of C1 (β-1, 4-glucan cellobiohydrolase or exo-β-1,4glucanase), Cc (endo-β-1,4-glucanase) and component and cellobiose (β-glucocidase). Hemicellulase enzyme consists of endo-β-1,4-xilanase, β-xilosidase, α-L arabinofuranosidase, α-D-glukuronidaseand asetil xilan esterase. This research aimed to study the activity of lignocellulosic enzyme, produced by cows in their rumen, which can be used as a bioactivator in rice husk degradation. This research resulted G6 and G7 bacteria, producing xylanase and cellulase with the activity of 0.004 U mL-1 and 0.021 U mL-1; 0.003 ( U mL-1) and 0.026 (U mL-1) respectively.

  11. Respiration triggers heme transfer from cytochrome c peroxidase to catalase in yeast mitochondria

    Science.gov (United States)

    Kathiresan, Meena; Martins, Dorival; English, Ann M.

    2014-01-01

    In exponentially growing yeast, the heme enzyme, cytochrome c peroxidase (Ccp1) is targeted to the mitochondrial intermembrane space. When the fermentable source (glucose) is depleted, cells switch to respiration and mitochondrial H2O2 levels rise. It has long been assumed that CCP activity detoxifies mitochondrial H2O2 because of the efficiency of this activity in vitro. However, we find that a large pool of Ccp1 exits the mitochondria of respiring cells. We detect no extramitochondrial CCP activity because Ccp1 crosses the outer mitochondrial membrane as the heme-free protein. In parallel with apoCcp1 export, cells exhibit increased activity of catalase A (Cta1), the mitochondrial and peroxisomal catalase isoform in yeast. This identifies Cta1 as a likely recipient of Ccp1 heme, which is supported by low Cta1 activity in ccp1Δ cells and the accumulation of holoCcp1 in cta1Δ mitochondria. We hypothesized that Ccp1’s heme is labilized by hyperoxidation of the protein during the burst in H2O2 production as cells begin to respire. To test this hypothesis, recombinant Ccp1 was hyperoxidized with excess H2O2 in vitro, which accelerated heme transfer to apomyoglobin added as a surrogate heme acceptor. Furthermore, the proximal heme Fe ligand, His175, was found to be ∼85% oxidized to oxo-histidine in extramitochondrial Ccp1 isolated from 7-d cells, indicating that heme labilization results from oxidation of this ligand. We conclude that Ccp1 responds to respiration-derived H2O2 via a previously unidentified mechanism involving H2O2-activated heme transfer to apoCta1. Subsequently, the catalase activity of Cta1, not CCP activity, contributes to mitochondrial H2O2 detoxification. PMID:25422453

  12. Respiration triggers heme transfer from cytochrome c peroxidase to catalase in yeast mitochondria.

    Science.gov (United States)

    Kathiresan, Meena; Martins, Dorival; English, Ann M

    2014-12-09

    In exponentially growing yeast, the heme enzyme, cytochrome c peroxidase (Ccp1) is targeted to the mitochondrial intermembrane space. When the fermentable source (glucose) is depleted, cells switch to respiration and mitochondrial H2O2 levels rise. It has long been assumed that CCP activity detoxifies mitochondrial H2O2 because of the efficiency of this activity in vitro. However, we find that a large pool of Ccp1 exits the mitochondria of respiring cells. We detect no extramitochondrial CCP activity because Ccp1 crosses the outer mitochondrial membrane as the heme-free protein. In parallel with apoCcp1 export, cells exhibit increased activity of catalase A (Cta1), the mitochondrial and peroxisomal catalase isoform in yeast. This identifies Cta1 as a likely recipient of Ccp1 heme, which is supported by low Cta1 activity in ccp1Δ cells and the accumulation of holoCcp1 in cta1Δ mitochondria. We hypothesized that Ccp1's heme is labilized by hyperoxidation of the protein during the burst in H2O2 production as cells begin to respire. To test this hypothesis, recombinant Ccp1 was hyperoxidized with excess H2O2 in vitro, which accelerated heme transfer to apomyoglobin added as a surrogate heme acceptor. Furthermore, the proximal heme Fe ligand, His175, was found to be ∼ 85% oxidized to oxo-histidine in extramitochondrial Ccp1 isolated from 7-d cells, indicating that heme labilization results from oxidation of this ligand. We conclude that Ccp1 responds to respiration-derived H2O2 via a previously unidentified mechanism involving H2O2-activated heme transfer to apoCta1. Subsequently, the catalase activity of Cta1, not CCP activity, contributes to mitochondrial H2O2 detoxification.

  13. Modifying Yeast Tolerance to Inhibitory Conditions of Ethanol Production Processes

    DEFF Research Database (Denmark)

    Caspeta, Luis; Castillo, Tania; Nielsen, Jens

    2015-01-01

    Saccharomyces cerevisiae strains having a broad range of substrate utilization, rapid substrate consumption, and conversion to ethanol, as well as good tolerance to inhibitory conditions are ideal for cost-competitive ethanol production from lignocellulose. A major drawback to directly design S....... cerevisiae tolerance to inhibitory conditions of lignocellulosic ethanol production processes is the lack of knowledge about basic aspects of its cellular signaling network in response to stress. Here, we highlight the inhibitory conditions found in ethanol production processes, the targeted cellular...... functions, the key contributions of integrated -omics analysis to reveal cellular stress responses according to these inhibitors, and current status on design-based engineering of tolerant and efficient S. cerevisiae strains for ethanol production from lignocellulose....

  14. Drosophila Regulate Yeast Density and Increase Yeast Community Similarity in a Natural Substrate

    OpenAIRE

    Stamps, Judy A.; Yang, Louie H.; Morales, Vanessa M.; Boundy-Mills, Kyria L.

    2012-01-01

    Drosophila melanogaster adults and larvae, but especially larvae, had profound effects on the densities and community structure of yeasts that developed in banana fruits. Pieces of fruit exposed to adult female flies previously fed fly-conditioned bananas developed higher yeast densities than pieces of the same fruits that were not exposed to flies, supporting previous suggestions that adult Drosophila vector yeasts to new substrates. However, larvae alone had dramatic effects on yeast densit...

  15. Inhibitory Compounds in Lignocellulosic Biomass Hydrolysates during Hydrolysate Fermentation Processes

    NARCIS (Netherlands)

    Zha, Y.; Muilwijk, B.; Coulier, L.C.; Punt, P.J.

    2012-01-01

    To compare the composition and performance of various lignocellulosic biomass hydrolysates as fermentation media, 8 hydrolysates were generated from a grass-like and a wood biomass. The hydrolysate preparation methods used were 1) dilute acid, 2) mild alkaline, 3) alkaline/peracetic acid, and 4)

  16. Energy and Environmental Performance of Bioethanol from Different Lignocelluloses

    Directory of Open Access Journals (Sweden)

    Lin Luo

    2010-01-01

    Full Text Available Climate change and the wish to reduce the dependence on oil are the incentives for the development of alternative energy sources. The use of lignocellulosic biomass together with cellulosic processing technology provides opportunities to produce fuel ethanol with less competition with food and nature. Many studies on energy analysis and life cycle assessment of second-generation bioethanol have been conducted. However, due to the different methodology used and different system boundary definition, it is difficult to compare their results. To permit a direct comparison of fuel ethanol from different lignocelluloses in terms of energy use and environmental impact, seven studies conducted in our group were summarized in this paper, where the same technologies were used to convert biomass to ethanol, the same system boundaries were defined, and the same allocation procedures were followed. A complete set of environmental impacts ranging from global warming potential to toxicity aspects is used. The results provide an overview on the energy efficiency and environmental performance of using fuel ethanol derived from different feedstocks in comparison with gasoline.

  17. Characteristics and kinetic study on pyrolysis of five lignocellulosic biomass via thermogravimetric analysis.

    Science.gov (United States)

    Chen, Zhihua; Hu, Mian; Zhu, Xiaolei; Guo, Dabin; Liu, Shiming; Hu, Zhiquan; Xiao, Bo; Wang, Jingbo; Laghari, Mahmood

    2015-09-01

    Pyrolysis characteristics and kinetic of five lignocellulosic biomass pine wood sawdust, fern (Dicranopteris linearis) stem, wheat stalk, sugarcane bagasse and jute (Corchorus capsularis) stick were investigated using thermogravimetric analysis. The pyrolysis of five lignocellulosic biomass could be divided into three stages, which correspond to the pyrolysis of hemicellulose, cellulose and lignin, respectively. Single Gaussian activation energy distributions of each stage are 148.50-201.13 kJ/mol with standard deviations of 2.60-13.37 kJ/mol. The kinetic parameters of different stages were used as initial guess values for three-parallel-DAEM model calculation with good fitting quality and fast convergence rate. The mean activation energy ranges of hemicellulose, cellulose and lignin were 148.12-164.56 kJ/mol, 171.04-179.54 kJ/mol and 175.71-201.60 kJ/mol, with standard deviations of 3.91-9.89, 0.29-1.34 and 23.22-27.24 kJ/mol, respectively. The mass fractions of hemicellulose, cellulose and lignin in lignocellulosic biomass were respectively estimated as 0.12-0.22, 0.54-0.65 and 0.17-0.29. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Influence of the crystalline structure of cellulose on the production of ethanol from lignocellulose biomass

    Science.gov (United States)

    Smuga-Kogut, Małgorzata; Zgórska, Kazimiera; Szymanowska-Powałowska, Daria

    2016-01-01

    In recent years, much attention has been devoted to the possibility of using lignocellulosic biomass for energy. Bioethanol is a promising substitute for conventional fossil fuels and can be produced from straw and wood biomass. Therefore, the aim of this paper was to investigate the effect of 1-ethyl-3-methylimidazolium pretreatment on the structure of cellulose and the acquisition of reducing sugars and bioethanol from cellulosic materials. Material used in the study was rye straw and microcrystalline cellulose subjected to ionic liquid 1-ethyl-3-methylimidazolium pretreatment. The morphology of cellulose fibres in rye straw and microcrystalline cellulose was imaged prior to and after ionic liquid pretreatment. Solutions of ionic liquid-treated and untreated cellulosic materials were subjected to enzymatic hydrolysis in order to obtain reducing sugars, which constituted a substrate for alcoholic fermentation. An influence of the ionic liquid on the cellulose structure, accumulation of reducing sugars in the process of hydrolysis of this material, and an increase in ethanol amount after fermentation was observed. The ionic liquid did not affect cellulolytic enzymes negatively and did not inhibit yeast activity. The amount of reducing sugars and ethyl alcohol was higher in samples purified with 1-ethyl-3-methy-limidazolium acetate. A change in the supramolecular structure of cellulose induced by the ionic liquid was also observed.

  19. Physicochemical characterization of the yeast cells and the waste lignocellulosic particles in the immobilization process for ethanol production

    DEFF Research Database (Denmark)

    Agudelo-Escobar, Lina María; Mussatto, Solange I.; Peñuela, Mariana

    2017-01-01

    Ethanol is one of the leading alternative fuels. Efforts have increased the development of technologies for producing ethanol efficiently and economically. The continuous fermentation using yeast cells immobilized in low‐cost materials is presented as an excellent alternative. We used four...... to confirm the hydrophobic or hydrophilic character and the free energies interaction was established. Images were obtained by scanning electron microscope, and determination of surface areas and volumes was performed by adsorption and desorption isotherms. It was established that cell surface properties...... are modified by the immobilization process to which they are subjected. It was evident that cell immobilization depended on the properties of the carrier, as well as cell surface properties. Thus, in order to improve the process of cell immobilization, it is essential to understand the type of carrier‐cell...

  20. C-Terminal Tyrosine Residue Modifications Modulate the Protective Phosphorylation of Serine 129 of α-Synuclein in a Yeast Model of Parkinson's Disease.

    Science.gov (United States)

    Kleinknecht, Alexandra; Popova, Blagovesta; Lázaro, Diana F; Pinho, Raquel; Valerius, Oliver; Outeiro, Tiago F; Braus, Gerhard H

    2016-06-01

    Parkinson´s disease (PD) is characterized by the presence of proteinaceous inclusions called Lewy bodies that are mainly composed of α-synuclein (αSyn). Elevated levels of oxidative or nitrative stresses have been implicated in αSyn related toxicity. Phosphorylation of αSyn on serine 129 (S129) modulates autophagic clearance of inclusions and is prominently found in Lewy bodies. The neighboring tyrosine residues Y125, Y133 and Y136 are phosphorylation and nitration sites. Using a yeast model of PD, we found that Y133 is required for protective S129 phosphorylation and for S129-independent proteasome clearance. αSyn can be nitrated and form stable covalent dimers originating from covalent crosslinking of two tyrosine residues. Nitrated tyrosine residues, but not di-tyrosine-crosslinked dimers, contributed to αSyn cytotoxicity and aggregation. Analysis of tyrosine residues involved in nitration and crosslinking revealed that the C-terminus, rather than the N-terminus of αSyn, is modified by nitration and di-tyrosine formation. The nitration level of wild-type αSyn was higher compared to that of A30P mutant that is non-toxic in yeast. A30P formed more dimers than wild-type αSyn, suggesting that dimer formation represents a cellular detoxification pathway in yeast. Deletion of the yeast flavohemoglobin gene YHB1 resulted in an increase of cellular nitrative stress and cytotoxicity leading to enhanced aggregation of A30P αSyn. Yhb1 protected yeast from A30P-induced mitochondrial fragmentation and peroxynitrite-induced nitrative stress. Strikingly, overexpression of neuroglobin, the human homolog of YHB1, protected against αSyn inclusion formation in mammalian cells. In total, our data suggest that C-terminal Y133 plays a major role in αSyn aggregate clearance by supporting the protective S129 phosphorylation for autophagy and by promoting proteasome clearance. C-terminal tyrosine nitration increases pathogenicity and can only be partially detoxified by

  1. Comparing cell viability and ethanol fermentation of the thermotolerant yeast Kluyveromyces marxianus and Saccharomyces cerevisiae on steam-exploded biomass treated with laccase.

    Science.gov (United States)

    Moreno, Antonio D; Ibarra, David; Ballesteros, Ignacio; González, Alberto; Ballesteros, Mercedes

    2013-05-01

    In this study, the thermotolerant yeast Kluyveromyces marxianus CECT 10875 was compared to the industrial strain Saccharomyces cerevisiae Ethanol Red for lignocellulosic ethanol production. For it, whole slurry from steam-exploded wheat straw was used as raw material, and two process configurations, simultaneous saccharification and fermentation (SSF) and presaccharification and simultaneous saccharification and fermentation (PSSF), were evaluated. Compared to S. cerevisiae, which was able to produce ethanol in both process configurations, K. marxianus was inhibited, and neither growth nor ethanol production occurred during the processes. However, laccase treatment of the whole slurry removed specifically lignin phenols from the overall inhibitory compounds present in the slurry and triggered the fermentation by K. marxianus, attaining final ethanol concentrations and yields comparable to those obtained by S. cerevisiae. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Different response to acetic acid stress in Saccharomyces cerevisiae wild-type and l-ascorbic acid-producing strains.

    Science.gov (United States)

    Martani, Francesca; Fossati, Tiziana; Posteri, Riccardo; Signori, Lorenzo; Porro, Danilo; Branduardi, Paola

    2013-09-01

    Biotechnological processes are of increasing significance for industrial production of fine and bulk chemicals, including biofuels. Unfortunately, under operative conditions microorganisms meet multiple stresses, such as non-optimal pH, temperature, oxygenation and osmotic stress. Moreover, they have to face inhibitory compounds released during the pretreatment of lignocellulosic biomasses, which constitute the preferential substrate for second-generation processes. Inhibitors include furan derivatives, phenolic compounds and weak organic acids, among which acetic acid is one of the most abundant and detrimental for cells. They impair cellular metabolism and growth, reducing the productivity of the process: therefore, the development of robust cell factories with improved production rates and resistance is of crucial importance. Here we show that a yeast strain engineered to endogenously produce vitamin C exhibits an increased tolerance compared to the parental strain when exposed to acetic acid at moderately toxic concentrations, measured as viability on plates. Starting from this evidence, we investigated more deeply: (a) the nature and levels of reactive oxygen species (ROS); (b) the activation of enzymes that act directly as detoxifiers of reactive oxygen species, such as superoxide dismutase (SOD) and catalase, in parental and engineered strains during acetic acid stress. The data indicate that the engineered strain can better recover from stress by limiting ROS accumulation, independently from SOD activation. The engineered yeast can be proposed as a model for further investigating direct and indirect mechanism(s) by which an antioxidant can rescue cells from organic acid damage; moreover, these studies will possibly provide additional targets for further strain improvements. Copyright © 2013 John Wiley & Sons, Ltd.

  3. Canonical correlations between chemical and energetic characteristics of lignocellulosic wastes

    Directory of Open Access Journals (Sweden)

    Thiago de Paula Protásio

    2012-09-01

    Full Text Available Canonical correlation analysis is a statistical multivariate procedure that allows analyzing linear correlation that may exist between two groups or sets of variables (X and Y. This paper aimed to provide canonical correlation analysis between a group comprised of lignin and total extractives contents and higher heating value (HHV with a group of elemental components (carbon, hydrogen, nitrogen and sulfur for lignocellulosic wastes. The following wastes were used: eucalyptus shavings; pine shavings; red cedar shavings; sugar cane bagasse; residual bamboo cellulose pulp; coffee husk and parchment; maize harvesting wastes; and rice husk. Only the first canonical function was significant, but it presented a low canonical R². High carbon, hydrogen and sulfur contents and low nitrogen contents seem to be related to high total extractives contents of the lignocellulosic wastes. The preliminary results found in this paper indicate that the canonical correlations were not efficient to explain the correlations between the chemical elemental components and lignin contents and higher heating values.

  4. New yeasts-new brews: modern approaches to brewing yeast design and development.

    Science.gov (United States)

    Gibson, B; Geertman, J-M A; Hittinger, C T; Krogerus, K; Libkind, D; Louis, E J; Magalhães, F; Sampaio, J P

    2017-06-01

    The brewing industry is experiencing a period of change and experimentation largely driven by customer demand for product diversity. This has coincided with a greater appreciation of the role of yeast in determining the character of beer and the widespread availability of powerful tools for yeast research. Genome analysis in particular has helped clarify the processes leading to domestication of brewing yeast and has identified domestication signatures that may be exploited for further yeast development. The functional properties of non-conventional yeast (both Saccharomyces and non-Saccharomyces) are being assessed with a view to creating beers with new flavours as well as producing flavoursome non-alcoholic beers. The discovery of the psychrotolerant S. eubayanus has stimulated research on de novo S. cerevisiae × S. eubayanus hybrids for low-temperature lager brewing and has led to renewed interest in the functional importance of hybrid organisms and the mechanisms that determine hybrid genome function and stability. The greater diversity of yeast that can be applied in brewing, along with an improved understanding of yeasts' evolutionary history and biology, is expected to have a significant and direct impact on the brewing industry, with potential for improved brewing efficiency, product diversity and, above all, customer satisfaction. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Vaginal yeast infection

    Science.gov (United States)

    Yeast infection - vagina; Vaginal candidiasis; Monilial vaginitis ... Most women have a vaginal yeast infection at some time. Candida albicans is a common type of fungus. It is often found in small amounts ...

  6. Ethanol Fermentation of Various Pretreated and Hydrolyzed Substrates at Low Initial pH

    Science.gov (United States)

    Kádár, Zsófia; Maltha, San Feng; Szengyel, Zsolt; Réczey, Kati; de Laat, Wim

    Lignocellulosic materials represent an abundant feedstock for bioethanol production. Because of their complex structure pretreatment is necessary to make it accessible for enzymatic attack. Steam pretreatment with or without acid catalysts seems to be one of the most promising techniques, which has already been applied for large variety of lignocellulosics in order to improve enzymatic digestibility. During this process a range of toxic compounds (lignin and sugar degradation products) are formed which inhibit ethanol fermentation. In this study, the toxicity of hemicellulose hydrolysates obtained in the steam pretreatment of spruce, willow, and corn stover were investigated in ethanol fermentation tests using a yeast strain, which has been previously reported to have a resistance to inhibitory compounds generated during steam pretreatment. To overcome bacterial contamination, fermentations were carried out at low initial pH. The fermentability of hemicellulose hydrolysates of pretreated lignocellulosic substrates at low pH gave promising results with the economically profitable final 5 vol% ethanol concentration corresponding to 85% of theoretical. Adaptation experiments have shown that inhibitor tolerance of yeast strain can be improved by subsequent transfer of the yeast to inhibitory medium.

  7. Modifying yeast tolerance to inhibitory conditions of ethanol production processes

    Directory of Open Access Journals (Sweden)

    Luis eCaspeta

    2015-11-01

    Full Text Available Saccharomyces cerevisiae strains having a broad range of substrate utilization, rapid substrate consumption and conversion to ethanol, as well as good tolerance to inhibitory conditions are ideal for cost-competitive ethanol production from lignocellulose. A major drawback to directly design S. cerevisiae tolerance to inhibitory conditions of lignocellulosic ethanol production processes is the lack of knowledge about basic aspects of its cellular signaling network in response to stress. Here we highlight the inhibitory conditions found in ethanol production processes, the targeted cellular functions, the key contributions of integrated –omics analysis to reveal cellular stress responses according to these inhibitors, and current status on design-based engineering of tolerant and efficient S. cerevisiae strains for ethanol production from lignocellulose.

  8. Novel endophytic yeast Rhodotorula mucilaginosa strain PTD3 I: production of xylitol and ethanol.

    Science.gov (United States)

    Bura, Renata; Vajzovic, Azra; Doty, Sharon L

    2012-07-01

    An endophytic yeast, Rhodotorula mucilaginosa strain PTD3, that was isolated from stems of hybrid poplar was found to be capable of production of xylitol from xylose, of ethanol from glucose, galactose, and mannose, and of arabitol from arabinose. The utilization of 30 g/L of each of the five sugars during fermentation by PTD3 was studied in liquid batch cultures. Glucose-acclimated PTD3 produced enhanced yields of xylitol (67% of theoretical yield) from xylose and of ethanol (84, 86, and 94% of theoretical yield, respectively) from glucose, galactose, and mannose. Additionally, this yeast was capable of metabolizing high concentrations of mixed sugars (150 g/L), with high yields of xylitol (61% of theoretical yield) and ethanol (83% of theoretical yield). A 1:1 glucose:xylose ratio with 30 g/L of each during double sugar fermentation did not affect PTD3's ability to produce high yields of xylitol (65% of theoretical yield) and ethanol (92% of theoretical yield). Surprisingly, the highest yields of xylitol (76% of theoretical yield) and ethanol (100% of theoretical yield) were observed during fermentation of sugars present in the lignocellulosic hydrolysate obtained after steam pretreatment of a mixture of hybrid poplar and Douglas fir. PTD3 demonstrated an exceptional ability to ferment the hydrolysate, overcome hexose repression of xylose utilization with a short lag period of 10 h, and tolerate sugar degradation products. In direct comparison, PTD3 had higher xylitol yields from the mixed sugar hydrolysate compared with the widely studied and used xylitol producer Candida guilliermondii.

  9. Deconstructing the genetic basis of spent sulphite liquor tolerance using deep sequencing of genome-shuffled yeast.

    Science.gov (United States)

    Pinel, Dominic; Colatriano, David; Jiang, Heng; Lee, Hung; Martin, Vincent Jj

    2015-01-01

    Identifying the genetic basis of complex microbial phenotypes is currently a major barrier to our understanding of multigenic traits and our ability to rationally design biocatalysts with highly specific attributes for the biotechnology industry. Here, we demonstrate that strain evolution by meiotic recombination-based genome shuffling coupled with deep sequencing can be used to deconstruct complex phenotypes and explore the nature of multigenic traits, while providing concrete targets for strain development. We determined genomic variations found within Saccharomyces cerevisiae previously evolved in our laboratory by genome shuffling for tolerance to spent sulphite liquor. The representation of these variations was backtracked through parental mutant pools and cross-referenced with RNA-seq gene expression analysis to elucidate the importance of single mutations and key biological processes that play a role in our trait of interest. Our findings pinpoint novel genes and biological determinants of lignocellulosic hydrolysate inhibitor tolerance in yeast. These include the following: protein homeostasis constituents, including Ubp7p and Art5p, related to ubiquitin-mediated proteolysis; stress response transcriptional repressor, Nrg1p; and NADPH-dependent glutamate dehydrogenase, Gdh1p. Reverse engineering a prominent mutation in ubiquitin-specific protease gene UBP7 in a laboratory S. cerevisiae strain effectively increased spent sulphite liquor tolerance. This study advances understanding of yeast tolerance mechanisms to inhibitory substrates and biocatalyst design for a biomass-to-biofuel/biochemical industry, while providing insights into the process of mutation accumulation that occurs during genome shuffling.

  10. [Effects of furfural on the growth and lipid production of oleaginous yeast Rhodotorula glutinis].

    Science.gov (United States)

    Yong, Zihan; Zhang, Xu; Tan, Tianwei

    2015-10-01

    In order to illustrate the effects of furfural, one of the most common inhibitory compounds in lignocellulosic hydrolysate, on oleaginous yeast Rhodotorula glutinis, we investigated the effects of different concentrations of furfural (0.1, 0.4, 0.6 and 1.5 g/L) on the biomass and lipid production of R. glutinis, as well as the effects of 1.0 g/L furfural on the utilization of glucose and xylose. Results showed that: when the furfural concentration reached 1.5 g/L, the lag phrase time was extended to 96 h, and the residual glucose was up to 17.7 g/L, with maximum biomass of only 6.6 g/L, which accounted for 47% of that in the basic medium (furfural-free), and the corresponding lipid content was reduced about 50%. Furfural showed lighter inhibitory degree on R. glutinis when xylose acted as the carbon source than glucose was the carbon source; more C18 fatty acids or unsaturated C18 fatty acids were generated in the presence of furfural.

  11. The Challenge of Lignocellulosic Bioenergy in a Water-Limited World

    Czech Academy of Sciences Publication Activity Database

    King, J. S.; Ceulemans, R.; Albaugh, J. M.; Dillen, S.; Domec, J. C.; Fichot, R.; Fischer, Milan; Leggett, Z.; Sucre, E.; Trnka, Miroslav; Zenone, T.

    2013-01-01

    Roč. 63, č. 2 (2013), s. 102-117 ISSN 0006-3568 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : climate change * lignocellulosic bioenergy * water availability * drought * sustainability Subject RIV: EH - Ecology, Behaviour Impact factor: 5.439, year: 2013

  12. Schizosaccharomyces japonicus: the fission yeast is a fusion of yeast and hyphae.

    Science.gov (United States)

    Niki, Hironori

    2014-03-01

    The clade of Schizosaccharomyces includes 4 species: S. pombe, S. octosporus, S. cryophilus, and S. japonicus. Although all 4 species exhibit unicellular growth with a binary fission mode of cell division, S. japonicus alone is dimorphic yeast, which can transit from unicellular yeast to long filamentous hyphae. Recently it was found that the hyphal cells response to light and then synchronously activate cytokinesis of hyphae. In addition to hyphal growth, S. japonicas has many properties that aren't shared with other fission yeast. Mitosis of S. japonicas is referred to as semi-open mitosis because dynamics of nuclear membrane is an intermediate mode between open mitosis and closed mitosis. Novel genetic tools and the whole genomic sequencing of S. japonicas now provide us with an opportunity for revealing unique characters of the dimorphic yeast. © 2013 The Author. Yeast Published by John Wiley & Sons Ltd.

  13. Fungal treatment of lignocellulosic biomass: Importance of fungal species, colonization and time on chemical composition and in vitro rumen degradability

    NARCIS (Netherlands)

    Kuijk, van S.J.A.; Sonnenberg, A.S.M.; Baars, J.J.P.; Hendriks, W.H.; Cone, J.W.

    2015-01-01

    The aim of this study is to evaluate fungal treatments to improve in vitro rumen degradability of lignocellulosic biomass. In this study four selective lignin degrading fungi, Ganoderma lucidum, Lentinula edodes, Pleurotus eryngii and Pleurotus ostreatus, were used to pre-treat lignocellulosic

  14. Highly thermostable xylanase production from a thermophilic Geobacillus sp. strain WSUCF1 utilizing lignocellulosic biomass

    Directory of Open Access Journals (Sweden)

    Aditya eBhalla

    2015-06-01

    Full Text Available AbstractEfficient enzymatic hydrolysis of lignocellulose to fermentable sugars requires a complete repertoire of biomass deconstruction enzymes. Hemicellulases play an important role in hydrolyzing hemicellulose component of lignocellulose to xylo-oligosaccharides and xylose. Thermostable xylanases have been a focus of attention as industrially important enzymes due to their long shelf life at high temperatures. Geobacillus sp. strain WSUCF1 produced thermostable xylanase activity (crude xylanase cocktail when grown on xylan or various inexpensive untreated and pretreated lignocellulosic biomasses such as prairie cord grass and corn stover. The optimum pH and temperature for the crude xylanase cocktail were 6.5 and 70ºC, respectively. The WSUCF1 crude xylanase was found to be highly thermostable with half-lives of 18 and 12 days at 60 and 70ºC, respectively. At 70ºC, rates of xylan hydrolysis were also found to be better with the WSUCF1 secretome than those with commercial enzymes, i.e., for WSUCF1 crude xylanase, CellicHTec2, and AccelleraseXY, the percent xylan conversions were 68.9, 49.4, and 28.92, respectively. To the best of our knowledge, WSUCF1 crude xylanase cocktail is among the most thermostable xylanases produced by thermophilic Geobacillus spp. and other thermophilic microbes (optimum growth temperature ≤70ºC. High thermostability, activity over wide range of temperatures, and better xylan hydrolysis than commercial enzymes make WSUCF1 crude xylanase suitable for thermophilic lignocellulose bioconversion processes.

  15. Effects of lignocellulosic composition and microwave power level on the gaseous product of microwave pyrolysis

    International Nuclear Information System (INIS)

    Huang, Yu-Fong; Chiueh, Pei-Te; Kuan, Wen-Hui; Lo, Shang-Lien

    2015-01-01

    Agricultural residues are abundant resources to produce renewable energy and valuable chemicals. This study focused on the effects of lignocellulosic composition and microwave power level on the gaseous product of microwave pyrolysis of agricultural residues. When agricultural residues were under microwave radiation within 10 min, the maximum temperatures of approximately 320, 420, and 530 °C were achieved at the microwave power levels of 300, 400, and 500 W, respectively. Gas yield increased with increasing microwave power level, whereas solid and liquid yields decreased. Besides, gaseous products with higher H 2 content and higher calorific values can be obtained at higher microwave power levels. In addition to microwave power level, lignocellulosic composition was also an important factor. H 2 and CO 2 yields increased with increasing hemicellulose content, whereas CH 4 and CO yields increased with increasing cellulose content. Four empirical equations were derived to present the contributions of lignocellulosic materials to the yields of gaseous components. - Highlights: • About 530 °C was reached within 10 min at a microwave power level of 500 W. • Gas yield increased with increasing microwave power level. • A high correlation between hemicellulose content and either H 2 or CO 2 yield. • A high correlation between cellulose content and either CH 4 or CO yield. • Empirical equations depict contribution of lignocellulosic content to gas yield

  16. Fungal Biodegradative Oxidants in Lignocellulose: Fluorescence Mapping and Correlation With Gene Expression

    Energy Technology Data Exchange (ETDEWEB)

    Hammel, Kenneth E. [Univ. of Wisconsin, Madison, WI (United States); Ralph, John [Univ. of Wisconsin, Madison, WI (United States); Hunt, Christopher G. [U.S. Forest Products Lab., Madison, WI (United States); Houtman, Carl J. [U.S. Forest Products Lab., Madison, WI (United States)

    2016-09-06

    This work focused on new methods for the detection of oxidation in natural substrates during the deconstruction of lignocellulose by microoganisms. Oxidation was the focus because all known biological systems that degrade lignin are oxidative. The detection methods involved the used of (a) micrometer-scale beads carrying a fluorescent dye that is sensitive to oxidation, (b) 13C-labeled synthetic lignins whose breakdown products can be assessed using mass spectrometry and nuclear magnetic resonance spectroscopy, and (c) a fluorometric stain that is highly sensitive to incipient oxidation during microbial attack. The results showed (a) that one white rot fungus, Phanerochaete chrysosporium, produces diffusible oxidants on wood, and that the onset of oxidation is coincident with the marked up-regulation of genes that encode ligninolytic peroxidases and auxiliary oxidative enzymes; (b) that a more selectively ligninolytic white rot fungus, Ceriporiopsis subvermispora, produces a highly diastereoselective oxidative system for attack on lignin; (c) that a brown rot fungus, Serpula lacrymans, uses extracellular hydroquinone metabolites to drive the production of lignocellulose-oxidizing free radicals; (d) that both white rot and brown rot fungi produce highly diffusible mild oxidants that modify lignocellulose at the earliest stage of substrate deconstruction; and (e) that lignin degradation in a tropical soil is not inhibited as much as expected during periods of flooding-induced hypoxia, which indicates that unknown mechanisms for attack on lignin remain to be discovered.

  17. A new method for recovery of cellulose from lignocellulosic bio-waste: Pile processing.

    Science.gov (United States)

    Tezcan, Erdem; Atıcı, Oya Galioğlu

    2017-12-01

    This paper presents a new delignification method (pile processing) for the recovery of cellulose from lignocellulosic bio-wastes, adapted from heap leaching technology in metallurgy. The method is based on the stacking of cellulosic materials in a pile, irrigation of the pile with aqueous reactive solution from the top, lignin and hemicellulose removal and enrichment of cellulose by the reactive solution while percolation occurs through the bottom of the pile, recirculating the reactive solution after adjusting several values such as chemical concentrations, and allow the system run until the desired time or cellulose purity. Laboratory scale systems were designed using fall leaves (FL) as lignocellulosic waste materials. The ideal condition for FL was noted as: 0.1g solid NaOH addition per gram of FL into the irrigating solution resulting in instant increase in pH to about 13.8, later allowing self-decrease in pH due to delignification over time down to 13.0, at which point another solid NaOH addition was performed. The new method achieved enrichment of cellulose from 30% to 81% and removal of 84% of the lignin that prevents industrial application of lignocellulosic bio-waste using total of 0.3g NaOH and 4ml of water per gram of FL at environmental temperature and pressure. While the stirring reactions used instead of pile processing required the same amount of NaOH, they needed at least 12ml of water and delignification was only 56.1%. Due to its high delignification performance using common and odorless chemicals and simple equipment in mild conditions, the pile processing method has great promise for the industrial evaluation of lignocellulosic bio-waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The development of effective pretreatment and saccharification techniques for lignocellulosic biomass using radiation

    International Nuclear Information System (INIS)

    Chung, Dyung Yeoup; Kim, Jin Hong; Lee, Seung Sik; Bai, Hyoung Woo; Lee, Jae Taek; Hong, Sung Hyun; Lee, Eun Mi; Kim, Mi Ja

    2011-12-01

    The bio-ethanol production from crop resource leads to several problems such as a shortage of provisions, soil acidification, and increase of crop price, whereas lignocellulosic biomass can overcome such problems as mentioned above. That is the reason why, the investigation of ethanol production originated from lignocellulosic materials has carried out all over the world. In present project, we focus on the new method of pretreatment using radiation as well as find out high efficiency process of saccharification through the new microorganisms and enzymes in order to achieve the price competitiveness. The enzymatic hydrolysis in lignocellulosic materials is inhibited by several factors such as crystalline of cellolose, hemicelluloses, and lignin. In order to overcome these obstacles, we devise phyco-chemical and phyco-physical treatments as a combination of 3% sulferic acid and 1000 kGy gamma irradiation and as a popping-1000 kGy gamma irradiation. Most lignocellulosic materials showed above 95% enzymatic hydrolysis using popping or popping-gamma irradiation, while the combination of dilute acid-gamma irradiation showed below 90% enzymatic hydrolysis. Moreover, popping treatment followed by gamma irradiation is much better than gamma irradiation followed by popping for enhancing enzymatic hydrolysis. In conclusions, in case of herbaceous biomass such as wheat straw and switch grass popping treatment, popping treatment only is the best method and in case of woody biomass like a popular fiber and overseas biomass like a coconut fiber, the combination of 1000 kGy gamma irradiation-popping treatments is the most effective method for enzymatic hydrolysis. The achieving 95% of enzymatic hydrolysis is owing to modification of lignin structure, removal of hemicelluloses, and destruction of cellulose crystalline. In addition, we investigated that a new cocktail of enzymes for hydrolysis was designed for boosting enzymatic hydrolysis

  19. The development of effective pretreatment and saccharification techniques for lignocellulosic biomass using radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Dyung Yeoup; Kim, Jin Hong; Lee, Seung Sik; Bai, Hyoung Woo; Lee, Jae Taek; Hong, Sung Hyun; Lee, Eun Mi; Kim, Mi Ja

    2011-12-15

    The bio-ethanol production from crop resource leads to several problems such as a shortage of provisions, soil acidification, and increase of crop price, whereas lignocellulosic biomass can overcome such problems as mentioned above. That is the reason why, the investigation of ethanol production originated from lignocellulosic materials has carried out all over the world. In present project, we focus on the new method of pretreatment using radiation as well as find out high efficiency process of saccharification through the new microorganisms and enzymes in order to achieve the price competitiveness. The enzymatic hydrolysis in lignocellulosic materials is inhibited by several factors such as crystalline of cellolose, hemicelluloses, and lignin. In order to overcome these obstacles, we devise phyco-chemical and phyco-physical treatments as a combination of 3% sulferic acid and 1000 kGy gamma irradiation and as a popping-1000 kGy gamma irradiation. Most lignocellulosic materials showed above 95% enzymatic hydrolysis using popping or popping-gamma irradiation, while the combination of dilute acid-gamma irradiation showed below 90% enzymatic hydrolysis. Moreover, popping treatment followed by gamma irradiation is much better than gamma irradiation followed by popping for enhancing enzymatic hydrolysis. In conclusions, in case of herbaceous biomass such as wheat straw and switch grass popping treatment, popping treatment only is the best method and in case of woody biomass like a popular fiber and overseas biomass like a coconut fiber, the combination of 1000 kGy gamma irradiation-popping treatments is the most effective method for enzymatic hydrolysis. The achieving 95% of enzymatic hydrolysis is owing to modification of lignin structure, removal of hemicelluloses, and destruction of cellulose crystalline. In addition, we investigated that a new cocktail of enzymes for hydrolysis was designed for boosting enzymatic hydrolysis.

  20. Production of ethanol from sugars and lignocellulosic biomass by Thermoanaerobacter J1 isolated from a hot spring in Iceland.

    Science.gov (United States)

    Jessen, Jan Eric; Orlygsson, Johann

    2012-01-01

    Thermophilic bacteria have gained increased attention as candidates for bioethanol production from lignocellulosic biomass. This study investigated ethanol production by Thermoanaerobacter strain J1 from hydrolysates made from lignocellulosic biomass in batch cultures. The effect of increased initial glucose concentration and the partial pressure of hydrogen on end product formation were examined. The strain showed a broad substrate spectrum, and high ethanol yields were observed on glucose (1.70 mol/mol) and xylose (1.25 mol/mol). Ethanol yields were, however, dramatically lowered by adding thiosulfate or by cocultivating strain J1 with a hydrogenotrophic methanogen with acetate becoming the major end product. Ethanol production from 4.5 g/L of lignocellulosic biomass hydrolysates (grass, hemp stem, wheat straw, newspaper, and cellulose) pretreated with acid or alkali and the enzymes Celluclast and Novozymes 188 was investigated. The highest ethanol yields were obtained on cellulose (7.5 mM·g(-1)) but the lowest on straw (0.8 mM·g(-1)). Chemical pretreatment increased ethanol yields substantially from lignocellulosic biomass but not from cellulose. The largest increase was on straw hydrolysates where ethanol production increased from 0.8 mM·g(-1) to 3.3 mM·g(-1) using alkali-pretreated biomass. The highest ethanol yields on lignocellulosic hydrolysates were observed with hemp hydrolysates pretreated with acid, 4.2 mM·g(-1).

  1. Yeast ecology of Kombucha fermentation.

    Science.gov (United States)

    Teoh, Ai Leng; Heard, Gillian; Cox, Julian

    2004-09-01

    Kombucha is a traditional fermentation of sweetened tea, involving a symbiosis of yeast species and acetic acid bacteria. Despite reports of different yeast species being associated with the fermentation, little is known of the quantitative ecology of yeasts in Kombucha. Using oxytetracycline-supplemented malt extract agar, yeasts were isolated from four commercially available Kombucha products and identified using conventional biochemical and physiological tests. During the fermentation of each of the four products, yeasts were enumerated from both the cellulosic pellicle and liquor of the Kombucha. The number and diversity of species varied between products, but included Brettanomyces bruxellensis, Candida stellata, Schizosaccharomyces pombe, Torulaspora delbrueckii and Zygosaccharomyces bailii. While these yeast species are known to occur in Kombucha, the enumeration of each species present throughout fermentation of each of the four Kombucha cultures demonstrated for the first time the dynamic nature of the yeast ecology. Kombucha fermentation is, in general, initiated by osmotolerant species, succeeded and ultimately dominated by acid-tolerant species.

  2. Lignocellulose Biomass: Constitutive Polymers. Biological Processes of Lignin Degradation

    International Nuclear Information System (INIS)

    Martin, C.; Manzanares, P.

    1994-01-01

    The structure of the lignocellulosic materials and the chemical composition of their main constitutive polymers, cellulose, hemicelluloses and lignin are described. The most promising transformation processes according to the type of biomass considered: hardwood, softwood an herbaceous and the perspectives of biotechnological processes for bio pulping, bio bleaching and effluents decolorisation in the paper pulp industry are also discussed. (Author) 7 refs

  3. Yeast genome sequencing:

    DEFF Research Database (Denmark)

    Piskur, Jure; Langkjær, Rikke Breinhold

    2004-01-01

    For decades, unicellular yeasts have been general models to help understand the eukaryotic cell and also our own biology. Recently, over a dozen yeast genomes have been sequenced, providing the basis to resolve several complex biological questions. Analysis of the novel sequence data has shown...... of closely related species helps in gene annotation and to answer how many genes there really are within the genomes. Analysis of non-coding regions among closely related species has provided an example of how to determine novel gene regulatory sequences, which were previously difficult to analyse because...... they are short and degenerate and occupy different positions. Comparative genomics helps to understand the origin of yeasts and points out crucial molecular events in yeast evolutionary history, such as whole-genome duplication and horizontal gene transfer(s). In addition, the accumulating sequence data provide...

  4. A bionic system with Fenton reaction and bacteria as a model for bioprocessing lignocellulosic biomass.

    Science.gov (United States)

    Zhang, Kejing; Si, Mengying; Liu, Dan; Zhuo, Shengnan; Liu, Mingren; Liu, Hui; Yan, Xu; Shi, Yan

    2018-01-01

    The recalcitrance of lignocellulosic biomass offers a series of challenges for biochemical processing into biofuels and bio-products. For the first time, we address these challenges with a biomimetic system via a mild yet rapid Fenton reaction and lignocellulose-degrading bacterial strain Cupriavidus basilensis B-8 (here after B-8) to pretreat the rice straw (RS) by mimicking the natural fungal invasion process. Here, we also elaborated the mechanism through conducting a systematic study of physicochemical changes before and after pretreatment. After synergistic Fenton and B-8 pretreatment, the reducing sugar yield was increased by 15.6-56.6% over Fenton pretreatment alone and 2.7-5.2 times over untreated RS (98 mg g -1 ). Morphological analysis revealed that pretreatment changed the surface morphology of the RS, and the increase in roughness and hydrophilic sites enhanced lignocellulose bioavailability. Chemical components analyses showed that B-8 removed part of the lignin and hemicellulose which caused the cellulose content to increase. In addition, the important chemical modifications also occurred in lignin, 2D NMR analysis of the lignin in residues indicated that the Fenton pretreatment caused partial depolymerization of lignin mainly by cleaving the β- O -4 linkages and by demethoxylation to remove the syringyl (S) and guaiacyl (G) units. B-8 could depolymerize amount of the G units by cleaving the β-5 linkages that interconnect the lignin subunits. A biomimetic system with a biochemical Fenton reaction and lignocellulose-degrading bacteria was confirmed to be able for the pretreatment of RS to enhance enzymatic hydrolysis under mild conditions. The high digestibility was attributed to the destruction of the lignin structure, partial hydrolysis of the hemicellulose and partial surface oxidation of the cellulose. The mechanism of synergistic Fenton and B-8 pretreatment was also explored to understand the change in the RS and the bacterial effects on

  5. Detoxifying enzyme studies on cotton leafhopper, Amrasca biguttula biguttula (Ishida, resistance to neonicotinoid insecticides in field populations in Karnataka, India

    Directory of Open Access Journals (Sweden)

    Halappa Banakar

    2016-12-01

    Full Text Available The cotton leafhopper (Amrasca biguttula biguttula Ishida is considered to be an alarming insect pest causing both quantitative and qualitative loss in cotton. In situ bioassay studies were done and the role of detoxifying enzymes in conferring resistance to neonicotinoid groups of insecticides in low (MUD, medium (DVG, high (HVR and very high (GLB pesticide usage areas of Karnataka were determined. Bioassay studies showed that imidacloprid, thiamethoxam, acetamiprid, thiacloprid and clothianidin registered varying levels of resistance for all the locations studied. The resistance ratio was high in imidacloprid (3.35, 8.57, 9.15 and 12.27 fold respectively and the lowest in dinoferuran (1.86, 5.13, 6.71 and 9.88 fold respectively. Furthermore, the enzyme activity ratio (glutathione-S-transferase was relatively greater, and corresponded to the higher LC50 values of neonicotinoids for very high, high, medium and low pesticide usage areas. Our study suggested that the higher activity of the detoxifying enzyme in the resistance population of cotton leafhopper apparently has a significant role in endowing resistance to neonicotinoid groups of insecticides. However, this study recommends using neonicotinoids in cotton growing areas with caution.

  6. NetPhosYeast: prediction of protein phosphorylation sites in yeast

    DEFF Research Database (Denmark)

    Ingrell, C.R.; Miller, Martin Lee; Jensen, O.N.

    2007-01-01

    sites compared to those in humans, suggesting the need for an yeast-specific phosphorylation site predictor. NetPhosYeast achieves a correlation coefficient close to 0.75 with a sensitivity of 0.84 and specificity of 0.90 and outperforms existing predictors in the identification of phosphorylation sites...

  7. Lignocellulose-derived porous phosphorus-doped carbon as advanced electrode for supercapacitors

    Science.gov (United States)

    Yi, Jianan; Qing, Yan; Wu, ChuTian; Zeng, Yinxiang; Wu, Yiqiang; Lu, Xihong; Tong, Yexiang

    2017-05-01

    Engineering porous heteroatom-doped carbon nanomaterials with remarkable capacitive performance is highly attractive. Herein, a simple and smart method has been developed to synthesize phosphorus (P) doped carbon with hierarchical porous structure derived from lignocellulose. Hierarchically porous P doped carbon is readily obtained by the pyrolysis of lignocellulose immersed in ZnCl2/NaH2PO4 aqueous solution, and exhibits excellent capacitive properties. The as-obtained P doped porous carbon delivers a significant capacitance of 133 F g-1 (146 mF cm-2) at a high current density of 10 A g-1 with outstanding rate performance. Furthermore, the P doped carbon electrode yields a long-term cycling durability with more than 97.9% capacitance retention after 10000 cycles as well. A symmetric supercapacitor with a maximum energy density of 4.7 Wh kg-1 is also demonstrated based on these P doped carbon electrodes.

  8. Fungal Beta-Glucosidases: A Bottleneck in Industrial Use of Lignocellulosic Materials

    Directory of Open Access Journals (Sweden)

    Peter S. Lübeck

    2013-09-01

    Full Text Available Profitable biomass conversion processes are highly dependent on the use of efficient enzymes for lignocellulose degradation. Among the cellulose degrading enzymes, beta-glucosidases are essential for efficient hydrolysis of cellulosic biomass as they relieve the inhibition of the cellobiohydrolases and endoglucanases by reducing cellobiose accumulation. In this review, we discuss the important role beta-glucosidases play in complex biomass hydrolysis and how they create a bottleneck in industrial use of lignocellulosic materials. An efficient beta-glucosidase facilitates hydrolysis at specified process conditions, and key points to consider in this respect are hydrolysis rate, inhibitors, and stability. Product inhibition impairing yields, thermal inactivation of enzymes, and the high cost of enzyme production are the main obstacles to commercial cellulose hydrolysis. Therefore, this sets the stage in the search for better alternatives to the currently available enzyme preparations either by improving known or screening for new beta-glucosidases.

  9. Integrating social and value dimensions into sustainability assessment of lignocellulosic biofuels.

    Science.gov (United States)

    Raman, Sujatha; Mohr, Alison; Helliwell, Richard; Ribeiro, Barbara; Shortall, Orla; Smith, Robert; Millar, Kate

    2015-11-01

    The paper clarifies the social and value dimensions for integrated sustainability assessments of lignocellulosic biofuels. We develop a responsible innovation approach, looking at technology impacts and implementation challenges, assumptions and value conflicts influencing how impacts are identified and assessed, and different visions for future development. We identify three distinct value-based visions. From a techno-economic perspective, lignocellulosic biofuels can contribute to energy security with improved GHG implications and fewer sustainability problems than fossil fuels and first-generation biofuels, especially when biomass is domestically sourced. From socio-economic and cultural-economic perspectives, there are concerns about the capacity to support UK-sourced feedstocks in a global agri-economy, difficulties monitoring large-scale supply chains and their potential for distributing impacts unfairly, and tensions between domestic sourcing and established legacies of farming. To respond to these concerns, we identify the potential for moving away from a one-size-fits-all biofuel/biorefinery model to regionally-tailored bioenergy configurations that might lower large-scale uses of land for meat, reduce monocultures and fossil-energy needs of farming and diversify business models. These configurations could explore ways of reconciling some conflicts between food, fuel and feed (by mixing feed crops with lignocellulosic material for fuel, combining livestock grazing with energy crops, or using crops such as miscanthus to manage land that is no longer arable); different bioenergy applications (with on-farm use of feedstocks for heat and power and for commercial biofuel production); and climate change objectives and pressures on farming. Findings are based on stakeholder interviews, literature synthesis and discussions with an expert advisory group.

  10. Utilizing thermophilic microbe in lignocelluloses based bioethanol production: Review

    Science.gov (United States)

    Sriharti, Agustina, Wawan; Ratnawati, Lia; Rahman, Taufik; Salim, Takiyah

    2017-01-01

    The utilization of thermophilic microbe has attracted many parties, particularly in producing an alternative fuel like ethanol. Bioethanol is one of the alternative energy sources substituting for earth oil in the future. The advantage of using bioethanol is that it can reduce pollution levels and global warming because the result of bioethanol burning doesn't bring in a net addition of CO2 into environment. Moreover, decrease in the reserves of earth oil globally has also contributed to the notion on searching renewable energy resources such as bioethanol. Indonesia has a high biomass potential and can be used as raw material for bioethanol. The utilization of these raw materials will reduce fears of competition foodstuffs for energy production. The enzymes that play a role in degrading lignocelluloses are cellulolytic, hemicellulolytic, and lignolytic in nature. The main enzyme with an important role in bioethanol production is a complex enzyme capable of degrading lignocelluloses. The enzyme can be produced by the thermophilik microbes of the groups of bacteria and fungi such as Trichoderma viride, Clostridium thermocellum, Bacillus sp. Bioethanol production is heavily affected by raw material composition, microorganism type, and the condition of fermentation used.

  11. Laccase Enzymology in Relation to Lignocellulose Processing

    DEFF Research Database (Denmark)

    Sitarz, Anna Katarzyna

    ) and investigated for production of enzymes under such conditions (Paper I). G. lucidum was found to produce high amounts of laccase which corresponded to its exceptional growth on lignocellulosic substrate and lignin. This observation led to a hypothesis that this particular laccase might act in a synergistic way...... cocktail preparation. This discovery is significant considering the fact that the cellulase cocktail preparations, namely Cellic®CTec1 and Cellic®CTec2, are improved in respect to phenolic-derived, and end-substrate inhibitors. Additionally, the molecular dynamics simulations (MD) of the obtained amino...

  12. Method of stabilizing wood or lignocellulose materials

    International Nuclear Information System (INIS)

    Pesek, M.; Dedek, V.; Plander, E.; Jarkovsky, J.

    1973-01-01

    Stabilization is effected by impregnating wood or lignocellulose materials with unsaturated monomers in a solution of organic solvents in the presence of swelling agents containing at least one organic halo compound with halogen content exceeding 30 wt. % and not exce--eding the amount corresponding to a saturated solution in the impregnation mixture. Polymerization is effected by ionizing radiation and is completed by the action of temperature in a range of 40 to 150 degC; at the same time, the solvents and the swelling agents should be removed. (B.S.)

  13. Effects of furfural on the respiratory metabolism of Saccharomyces cerevisiae in glucose-limited chemostats,

    OpenAIRE

    Sarvari Horvath, I; Franzén, C J; Taherzadeh, M J; Niklasson, C; Lidén, Gunnar

    2003-01-01

    Effects of furfural on the aerobic metabolism of the yeast Saccharomyces cerevisiae were studied by performing chemostat experiments, and the kinetics of furfural conversion was analyzed by performing dynamic experiments. Furfural, an important inhibitor present in lignocellulosic hydrolysates, was shown to have an inhibitory effect on yeast cells growing respiratively which was much greater than the inhibitory effect previously observed for anaerobically growing yeast cells. The residual fur...

  14. Technoeconomic analysis of biofuels: A wiki-based platform for lignocellulosic biorefineries

    DEFF Research Database (Denmark)

    Klein-Marcuschamer, Daniel; Oleskowicz-Popiel, Piotr; Simmons, Blake A.

    2010-01-01

    We present a process model for a lignocellulosic ethanol biorefinery that is open to the biofuels academic community. Beyond providing a series of static results, the wiki-based platform provides a dynamic and transparent tool for analyzing, exploring, and communicating the impact of process adva...

  15. Preparation, characterization, and microbial degradation of specifically radiolabeled (/sup 14/C)lignocelluloses from marine and fresh water macrophytes. [Spartina alterniflora; Juncus roemerianus; Rhizophora mangle; Carex walteriana

    Energy Technology Data Exchange (ETDEWEB)

    Benner, R.; Maccubbin, A.E.; Hodson, R.E.

    1984-02-01

    Specifically radiolabeled (/sup 14/C-lignin)lignocelluloses were prepared from the aquatic macrophytes Spartina alterniflora, Juncus roemerianus, Rhizophora mangle, and Carex walteriana by using (/sup 14/C)phenylalanine, (/sup 14/C)tyrosine, and (/sup 14/C)cinnamic acid as precursors. Specifically radiolabeled (/sup 14/C-polysaccharide)lignocelluloses were prepared by using (/sup 14/C)glucose as precursor. The rates of microbial degradation varied among (/sup 14/C-lignin)lignocelluloses labeled with different lignin precursors within the same plant species. In herbaceous plants, significant amounts (8 to 24%) of radioactivity from (/sup 14/C)phenylalanine and (/sup 14/C)tyrosine were found associated with protein. Microbial degradation of radiolabeled protein resulted in overestimation of lignin degradation rates in lignocelluloses derived from herbaceous aquatic plants. Other differences in degradation rates among (/sup 14/C-lignin)lignocelluloses from the same plant species were attributable to differences in the amount of label being associated with ester-linked subunits of peripheral lignin. After acid hydrolysis of (/sup 14/C-polysaccharide)lignocelluloses, radioactivity was detected in several sugars, although most of the radioactivity was distributed between glucose and xylose. After 576 h of incubation with salt marsh sediments, 38% of the polysaccharide component and between 6 and 16% of the lignin component (depending on the precursor) of J. roemerianus lignocellulose was mineralized to /sup 14/CO/sub 2/; during the same incubation period, 30% of the polysaccharide component and between 12 and 18% of the lignin component of S. alterniflora lignocellulose was mineralized.

  16. Changes in birchwood cellulose in the presence of sulfuric acid during furfural production. I. Dynamics of lignocellulose formation

    Energy Technology Data Exchange (ETDEWEB)

    Vedernikov, N.A.; Roze, I.; Trautmane, I.; Okonova, Z.O.; Kruma, I.

    1981-01-01

    The yields of lignocellulose formed during manufacture of furfural from birch sawdust in the presence of 10-90% H/sub 2/SO/sub 4/ at 137-167 degrees decreased linearly with increasing temperature and increases with increasing H/sub 2/SO/sub 4/ concentration. A drastic increase in lignocellulose yield was observed when H/sub 2/SO/sub 4/ concentration was increased from 10 to 30%.

  17. Potential of xylose-fermented yeast isolated from sugarcane bagasse waste for xylitol production using hydrolysate as carbon source

    Directory of Open Access Journals (Sweden)

    Kusumawadee Thancharoen

    2016-10-01

    Full Text Available Xylitol is a high value sugar alcohol that is used as a sweetener. In the past years, the biological process of D-xylose from lignocellulosic material into xylitol has gained increasing interest as an alternative production method. In this study, sugarcane bagasse was used as raw material for xylitol production because of its high efficiency, reduced industrial cost, and high concentration of xylose. Pre-treatment of sugarcane bagasse with sulfuric acid was performed with various conditions. The results showed that the optimum condition was exhibited for 3.1% sulfuric acid at 126°C for 18 min producing 19 g/l xylose. Isolated yeasts from the sugarcane bagasse were selected and tested for xylitol ability from xylose. Results showed that Candida tropicalis KS 10-3 (from 72 isolates had the highest ability and produced 0.47 g xylitol/ g xylose in 96 hrs of cultivation containing 32.30 g/l xylose was used as the production medium.

  18. Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling during ethanol fermentation

    Directory of Open Access Journals (Sweden)

    Lili Li

    2017-03-01

    Full Text Available Objectives: To improve ethanolic fermentation performance of self-flocculating yeast, difference between a flocculating yeast strain and a regular industrial yeast strain was analyzed by transcriptional and metabolic approaches. Results: The number of down-regulated (industrial yeast YIC10 vs. flocculating yeast GIM2.71 and up-regulated genes were 4503 and 228, respectively. It is the economic regulation for YIC10 that non-essential genes were down-regulated, and cells put more “energy” into growth and ethanol production. Hexose transport and phosphorylation were not the limiting-steps in ethanol fermentation for GIM2.71 compared to YIC10, whereas the reaction of 1,3-disphosphoglycerate to 3-phosphoglycerate, the decarboxylation of pyruvate to acetaldehyde and its subsequent reduction to ethanol were the most limiting steps. GIM2.71 had stronger stress response than non-flocculating yeast and much more carbohydrate was distributed to other bypass, such as glycerol, acetate and trehalose synthesis. Conclusions: Differences between flocculating yeast and regular industrial yeast in transcription and metabolite profiling will provide clues for improving the fermentation performance of GIM2.71.

  19. Comparative environmental performance of lignocellulosic ethanol from different feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Garcia, Sara; Moreira, M. Teresa; Feijoo, Gumersindo [Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2010-09-15

    A renewable biofuel economy is projected as a pathway to decrease dependence on fossil fuels as well as to reduce greenhouse gases (GHG) emissions. Ethanol produced on large-scale from lignocellulosic raw materials is considered the most potential next generation automotive fuel. In this paper, a Life Cycle Assessment model was developed to evaluate the environmental implications of the production of ethanol from five lignocellulosic materials: alfalfa stems, poplar, Ethiopian mustard, flax shives and hemp hurds and its use in passenger cars. Two ethanol-based fuel applications, E10 (a mixture of 10% ethanol and 90% gasoline by volume) and E85 (85% ethanol and 15% gasoline by volume) were assessed and the results were compared to those of conventional gasoline (CG) in an equivalent car. The environmental performance was assessed in terms of fossil fuels requirements, global warming, photochemical oxidant formation, acidification and eutrophication by means of the Life Cycle Assessment (LCA) methodology in order to identify the best environmental friendly lignocellulosic source. The results show that, compared to CG, life cycle greenhouse gases emissions are lower for etanol blends, specifically up to 145% lower for E85-fueled car derived from Ethiopian mustard. This crop is also the best option in terms of eutrophying emissions regardless the ratio of ethanol in the blend. In the remaining impact categories, other feedstocks are considered beneficial, that is, poplar in the case of photochemical oxidants formation and flax shives for acidification. Concerning fossil fuels requirements, decreases up to 10% and 63% for E10 and E85 derived from hemp hurds and Ethiopian mustard, respectively, were obtained. According to the results, the study clearly demonstrates the importance of using low intensive energy and high biomass yield crops. LCA procedure helps to identify the key areas in the ethanol production life cycle where the researchers and technicians need to work

  20. Production of Ethanol from Sugars and Lignocellulosic Biomass by Thermoanaerobacter J1 Isolated from a Hot Spring in Iceland

    Directory of Open Access Journals (Sweden)

    Jan Eric Jessen

    2012-01-01

    Full Text Available Thermophilic bacteria have gained increased attention as candidates for bioethanol production from lignocellulosic biomass. This study investigated ethanol production by Thermoanaerobacter strain J1 from hydrolysates made from lignocellulosic biomass in batch cultures. The effect of increased initial glucose concentration and the partial pressure of hydrogen on end product formation were examined. The strain showed a broad substrate spectrum, and high ethanol yields were observed on glucose (1.70 mol/mol and xylose (1.25 mol/mol. Ethanol yields were, however, dramatically lowered by adding thiosulfate or by cocultivating strain J1 with a hydrogenotrophic methanogen with acetate becoming the major end product. Ethanol production from 4.5 g/L of lignocellulosic biomass hydrolysates (grass, hemp stem, wheat straw, newspaper, and cellulose pretreated with acid or alkali and the enzymes Celluclast and Novozymes 188 was investigated. The highest ethanol yields were obtained on cellulose (7.5 mM·g−1 but the lowest on straw (0.8 mM·g−1. Chemical pretreatment increased ethanol yields substantially from lignocellulosic biomass but not from cellulose. The largest increase was on straw hydrolysates where ethanol production increased from 0.8 mM·g−1 to 3.3 mM·g−1 using alkali-pretreated biomass. The highest ethanol yields on lignocellulosic hydrolysates were observed with hemp hydrolysates pretreated with acid, 4.2 mM·g−1.

  1. The potential of lignocellulosic ethanol production in the Mediterranean Basin

    Energy Technology Data Exchange (ETDEWEB)

    Faraco, Vincenza [Department of Organic Chemistry and Biochemistry, University of Naples ' ' Federico II' ' , Naples (Italy); School of Biotechnological Sciences, University of Naples ' ' Federico II' ' , Naples (Italy); Hadar, Yitzhak [Department of Microbiology and Plant Pathology, The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot (Israel)

    2011-01-15

    This review provides an overview of the potential of bioethanol fuel production from lignocellulosic residues in the Mediterranean Basin. Residues from cereal crops, olive trees, and tomato and grape processing are abundant lignocellulosic wastes in France, Italy, Spain, Turkey and Egypt, where their use as raw materials for ethanol production could give rise to a potential production capacity of 13 Mtoe of ethanol. Due to the lack of sufficient amounts of agricultural residues in all of the other Mediterranean countries, use of the cellulosic content of municipal solid waste (MSW) as feedstock for ethanol fuel production is also proposed. A maximum potential production capacity of 30 Mtoe of ethanol could be achieved from 50% of the 180 million tons of waste currently produced annually in the Mediterranean Basin, the management of which has become a subject of serious concern. However, to make large-scale ethanol production from agricultural residues and MSW a medium-term feasible goal in the Mediterranean Basin, huge efforts are needed to achieve the required progress in cellulose ethanol technologies and to overcome several foreseeable constraints. (author)

  2. Ethanol production by Clostridium thermocellum grown on hydrothermally and organosolv-pretreated lignocellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Hoermeyer, H F; Bonn, G; Bobleter, O; Tailliez, P; Millet, J; Girard, H; Aubert, J P

    1988-12-01

    Two strains of the thermophilic anaerobe Clostridium thermocellum, the wild type NCIB 10682 and its ethanol-hyperproductive mutant 647, were tested for their ability to grow on natural lignocellulosic materials (poplar wood, wheat straw) which had been pretreated by either hydrothermolysis or an organosolv process. For both materials and both strains, the dependencies of substrate accessibility on the pretreatment temperature were established in terms of cellulose hydrolysis and of product formation. In addition to the non-pH-controlled shake flask assays, in vitro experiments with cell-free culture supernatant and in vivo cellulolyses under pH regulation in a laboratory fermenter indicated that lignocellulosics pretreated at approx. 230/sup 0/C were degraded efficiently by the Clostridium strains investigated.

  3. Formation of degradation compounds from lignocellulosic biomass in the biorefinery: sugar reaction mechanisms

    DEFF Research Database (Denmark)

    Rasmussen, Helena; Sørensen, Hanne R.; Meyer, Anne S.

    2014-01-01

    , several aldehydes and ketones and many different organic acids and aromatic compounds may be generated during hydrothermal treatment of lignocellulosic biomass. The reaction mechanisms are of interest because the very same compounds that are possible inhibitors for biomass processing enzymes......The degradation compounds formed during pretreatment when lignocellulosic biomass is processed to ethanol or other biorefinery products include furans, phenolics, organic acids, as well as mono- and oligomeric pentoses and hexoses. Depending on the reaction conditions glucose can be converted to 5......-(hydroxymethyl)-2-furaldehyde (HMF) and/or levulinic acid, formic acid and different phenolics at elevated temperatures. Correspondingly, xylose can follow different reaction mechanisms resulting in the formation of furan-2-carbaldehyde (furfural) and/or various C-1 and C-4 compounds. At least four routes...

  4. SIMULTANEOUS PRETREATMENT OF LIGNOCELLULOSE AND HYDROLYSIS OF STARCH IN MIXTURES TO SUGARS

    Directory of Open Access Journals (Sweden)

    Hamzeh Hoseinpour

    2010-11-01

    Full Text Available Mixtures of starch and lignocelluloses are available in many industrial, agricultural, and municipal wastes and residuals. In this work, dilute sulfuric acid was used for simultaneous pretreatment of lignocellulose and hydrolysis of starch, to obtain a maximum amount of fermentable sugar after enzymatic hydrolysis with cellulase and β-glucosidase. The acid treatment was carried out at 70-150°C with 0-1% (v/v acid concentration and 5-15% (w/v solids concentration for 0-40 minutes. Under the optimum conditions, obtained at 130°C, 1% acid, and 7.5% solids loading for 30 min, the starch was almost completely converted to glucose. However, the acid treatment was not successful for efficient hydrolysis of pure cellulose. A mixture of pine softwood and potato as representatives of lignocellulosic and starch components, respectively, were treated at the optimum conditions for acid hydrolysis of starch. The dilute-acid treatment resulted in 1.2, 60.5, and 23.6% hydrolysis of glucan, xylan, and mannan of pine wood and 67% of potato starch to fermentable sugars. After the acid treatment, the solid residue of the mixture was subjected to enzymatic hydrolysis. The enzymatic hydrolysis under the optimum conditions resulted in conversion of 76% of the glucan in the treated softwood. Therefore, using acid treatment of the mixture is a promising process for pretreatment of wood in addition to the hydrolysis of starch.

  5. Yeasts and yeast-like organisms associated with fruits and blossoms of different fruit trees.

    Science.gov (United States)

    Vadkertiová, Renáta; Molnárová, Jana; Vránová, Dana; Sláviková, Elena

    2012-12-01

    Yeasts are common inhabitants of the phyllosphere, but our knowledge of their diversity in various plant organs is still limited. This study focused on the diversity of yeasts and yeast-like organisms associated with matured fruits and fully open blossoms of apple, plum, and pear trees, during 2 consecutive years at 3 localities in southwest Slovakia. The occurrence of yeasts and yeast-like organisms in fruit samples was 2½ times higher and the yeast community more diverse than that in blossom samples. Only 2 species (Aureobasidium pullulans and Metschnikowia pulcherrima) occurred regularly in the blossom samples, whereas Galactomyces candidus, Hanseniaspora guilliermondii, Hanseniaspora uvarum, M. pulcherrima, Pichia kluyveri, Pichia kudriavzevii, and Saccharomyces cerevisiae were the most frequently isolated species from the fruit samples. The ratio of the number of samples where only individual species were present to the number of samples where 2 or more species were found (consortium) was counted. The occurrence of individual species in comparison with consortia was much higher in blossom samples than in fruit samples. In the latter, consortia predominated. Aureobasidium pullulans, M. pulcherrima, and S. cerevisiae, isolated from both the fruits and blossoms, can be considered as resident yeast species of various fruit tree species cultivated in southwest Slovakia localities.

  6. PREPARATION OF VARIOUS TYPES OF PULP FROM OIL PALM LIGNOCELLULOSIC RESIDUES

    Institute of Scientific and Technical Information of China (English)

    RyoheiTanaka; LehCheuPeng; WanRosliWanDaud

    2004-01-01

    Oil palm, Elaeis Guineensis, (Figure 1) is one of the most important plants in Malaysia. It produces palm oil and palm kernel oil, which is widely being used in food and other industries such as detergents and cosmetics. Malaysia is the world's largest producer and exporter of the oil, so that the country's economy is very much dependent on these oil products. Although oil from the palm tree is an excellent product for the country, residues from oil palm have not been used sufficiently. In this 10-15 years, development in new technologies for utilizing this lignocellulosic waste is categorized as one of the most important issues in science policy of Malaysia. Here we would like to introduce recent situation of palm oil and oil palm lignocellulosic residues at the first part of this paper. In the second part, our recent studies on the preparation of pulps for different purposes will be summarized.

  7. Literature Review of Physical and Chemical Pretreatment Processes for Lignocellulosic Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Harmsen, P.; Bakker, R. [Wageningen University and Research centre WUR, Food and Biobased Research WUR-FBR, Wageningen (Netherlands); Huijgen, W.J.J. [ECN Biomass, Coal and Environment, Petten (Netherlands); Bermudez Lopez, L. [Abengoa Bioenergia Nuevas Tecnologias ABNT (Spain)

    2010-09-15

    This literature review was performed within the BioSynergy project (2007-2010). BioSynergy is a European Integrated Project supported through the Sixth Framework Programme for Research and Technological Development (038994-SES6). BioSynergy stands for 'BIOmass for the market competitive and environmentally friendly SYNthesis of bio-products together with the production of secondary enERGY carriers through the biorefinery approach'. Within the BioSynergy project the overall goal of the pretreatment routes being developed is to convert raw lignocellulosic biomass into its composing sugars and lignin in a market competitive and environmentally sustainable way. This report reviews lignocellulose pretreatment in general as well as specific pretreatment technologies that are developed within the BioSynergy project including steam explosion (ABNT), mechanical/alkaline fractionation (WUR) and organosolv fractionation (ECN). In addition to these pretreatment technologies, other pretreatment technologies are studied within the BioSynergy project such as acetic/formic acid pretreatment and mild- and strong acid pretreatment.

  8. Clostridium species strain BOH3 tolerates and transforms inhibitors from horticulture waste hydrolysates.

    Science.gov (United States)

    Yan, Yu; He, Jianzhong

    2017-08-01

    Conversion of lignocellulosic hydrolysate to biofuels is impeded by the toxic effects of inhibitors that are generated during pretreatment and hydrolysis processes. Here we describe a wild-type Clostridium sp. strain BOH3 with high tolerance to the lignocellulose-derived inhibitors and its capability to transform these inhibitors. Strain BOH3 is capable of tolerating over 60 mM furfural, 60 mM hydroxymethylfurfural, and 6.6 mM vanillin, respectively, and is able to convert 53.74 ± 0.37 mM furfural into furfuryl alcohol within 90 h. The high furfural tolerance and its biotransformation by strain BOH3, which is correlated to the high transcription levels of two short-chain dehydrogenase/reductases, enable strain BOH3 to produce 5.15 ± 0.52 g/L butanol from dilute sulfuric acid pretreated horticultural waste hydrolysate (HWH) that bypassed the detoxification step. The capability of strain BOH3 to produce butanol from un-detoxified HWH lays the foundation of cost-effective biofuel production from lignocellulosic materials.

  9. Interaction Between Yeasts and Zinc

    Science.gov (United States)

    Nicola, Raffaele De; Walker, Graeme

    Zinc is an essential trace element in biological systems. For example, it acts as a cellular membrane stabiliser, plays a critical role in gene expression and genome modification and activates nearly 300 enzymes, including alcohol dehydrogenase. The present chapter will be focused on the influence of zinc on cell physiology of industrial yeast strains of Saccharomyces cerevisiae, with special regard to the uptake and subsequent utilisation of this metal. Zinc uptake by yeast is metabolism-dependent, with most of the available zinc translocated very quickly into the vacuole. At cell division, zinc is distributed from mother to daughter cells and this effectively lowers the individual cellular zinc concentration, which may become zinc depleted at the onset of the fermentation. Zinc influences yeast fermentative performance and examples will be provided relating to brewing and wine fermentations. Industrial yeasts are subjected to several stresses that may impair fermentation performance. Such stresses may also impact on yeast cell zinc homeostasis. This chapter will discuss the practical implications for the correct management of zinc bioavailability for yeast-based biotechnologies aimed at improving yeast growth, viability, fermentation performance and resistance to environmental stresses

  10. Boosting LPMO-driven lignocellulose degradation by polyphenol oxidase-activated lignin building blocks

    NARCIS (Netherlands)

    Frommhagen, Matthias; Mutte, Sumanth Kumar; Westphal, Adrie H.; Koetsier, Martijn J.; Hinz, Sandra W.A.; Visser, Jaap; Vincken, Jean Paul; Weijers, Dolf; Berkel, Van Willem J.H.; Gruppen, Harry; Kabel, Mirjam A.

    2017-01-01

    Background: Many fungi boost the deconstruction of lignocellulosic plant biomass via oxidation using lytic polysaccharide monooxygenases (LPMOs). The application of LPMOs is expected to contribute to ecologically friendly conversion of biomass into fuels and chemicals. Moreover, applications of

  11. Lignocellulosic composites prepared utilizing aqueous alkaline/urea solutions with cold temperatures

    Science.gov (United States)

    Lignocellulosic composites (LCs) were fabricated by partially dissolving cotton to create a matrix that was reinforced with Osage orange wood (OOW) particles and/or Blue agave fibers (AF). LCs were composed of 15-35% cotton matrix: 65-85% OWW/AF reinforcement. The matrix was produced by soaking cott...

  12. Isolation, characterization and transcriptome analysis of a novel Antarctic Aspergillus sydowii strain MS-19 as a potential lignocellulosic enzyme source.

    Science.gov (United States)

    Cong, Bailin; Wang, Nengfei; Liu, Shenghao; Liu, Feng; Yin, Xiaofei; Shen, Jihong

    2017-05-30

    With the growing demand for fossil fuels and the severe energy crisis, lignocellulose is widely regarded as a promising cost-effective renewable resource for ethanol production, and the use of lignocellulose residues as raw material is remarkable. Polar organisms have important value in scientific research and development for their novelty, uniqueness and diversity. In this study, a fungus Aspergillus sydowii MS-19, with the potential for lignocellulose degradation was screened out and isolated from an Antarctic region. The growth profile of Aspergillus sydowii MS-19 was measured, revealing that Aspergillus sydowii MS-19 could utilize lignin as a sole carbon source. Its ability to synthesize low-temperature lignin peroxidase (Lip) and manganese peroxidase (Mnp) enzymes was verified, and the properties of these enzymes were also investigated. High-throughput sequencing was employed to identify and characterize the transcriptome of Aspergillus sydowii MS-19. Carbohydrate-Active Enzymes (CAZyme)-annotated genes in Aspergillus sydowii MS-19 were compared with those in the brown-rot fungus representative species, Postia placenta and Penicillium decumbens. There were 701CAZymes annotated in Aspergillus sydowii MS-19, including 17 cellulases and 19 feruloyl esterases related to lignocellulose-degradation. Remarkably, one sequence annotated as laccase was obtained, which can degrade lignin. Three peroxidase sequences sharing a similar structure with typical lignin peroxidase and manganese peroxidase were also found and annotated as haem-binding peroxidase, glutathione peroxidase and catalase-peroxidase. In this study, the fungus Aspergillus sydowii MS-19 was isolated and shown to synthesize low-temperature lignin-degrading enzymes: lignin peroxidase (Lip) and manganese peroxidase (Mnp). These findings provide useful information to improve our understanding of low-temperature lignocellulosic enzyme production by polar microorganisms and to facilitate research and

  13. The Chemistry and Technology of Furfural Production in Modern Lignocellulose-Feedstock Biorefineries

    NARCIS (Netherlands)

    Marcotullio, G.

    2011-01-01

    This dissertation deals with biorefinery technology development, i.e. with the development of sustainable industrial methods aimed at the production of chemicals, fuels, heat and power from lignocellulosic biomass. This work is particularly focused on the production of furfural from

  14. Entropy analysis in yeast DNA

    International Nuclear Information System (INIS)

    Kim, Jongkwang; Kim, Sowun; Lee, Kunsang; Kwon, Younghun

    2009-01-01

    In this article, we investigate the language structure in yeast 16 chromosomes. In order to find it, we use the entropy analysis for codons (or amino acids) of yeast 16 chromosomes, developed in analysis of natural language by Montemurro et al. From the analysis, we can see that there exists a language structure in codons (or amino acids) of yeast 16 chromosomes. Also we find that the grammar structure of amino acids of yeast 16 chromosomes has a deep relationship with secondary structure of protein.

  15. Ethanol production from non-detoxified whole slurry of sulfite-pretreated empty fruit bunches at a low cellulase loading

    Science.gov (United States)

    Jinlan Cheng; Shao-Yuan Leu; J.Y. Zhu; Thomas W. Jeffries

    2014-01-01

    Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) was applied to an empty fruit bunches (EFB) for ethanol production. SPORL facilitated delignification through lignin sulfonation and dissolution of xylan to result in a highly digestible substrate. The pretreated whole slurry was enzymatically saccharified at a solids loading of 18% using a...

  16. Process performance and comparative metagenomic analysis during co-digestion of manure and lignocellulosic biomass for biogas production

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Treu, Laura

    2017-01-01

    Mechanical pretreatment is considered to be a fast and easily applicable method to prepare the biomass for anaerobic digestion. In the present study, the effect of mechanical pretreatment on lignocellulosic silages biodegradability was elucidated in batch reactors. Moreover, co-digestion of the s......Mechanical pretreatment is considered to be a fast and easily applicable method to prepare the biomass for anaerobic digestion. In the present study, the effect of mechanical pretreatment on lignocellulosic silages biodegradability was elucidated in batch reactors. Moreover, co...

  17. Yeast flocculation: New story in fuel ethanol production.

    Science.gov (United States)

    Zhao, X Q; Bai, F W

    2009-01-01

    Yeast flocculation has been used in the brewing industry to facilitate biomass recovery for a long time, and thus its mechanism of yeast flocculation has been intensively studied. However, the application of flocculating yeast in ethanol production garnered attention mainly in the 1980s and 1990s. In this article, updated research progress in the molecular mechanism of yeast flocculation and the impact of environmental conditions on yeast flocculation are reviewed. Construction of flocculating yeast strains by genetic approach and utilization of yeast flocculation for ethanol production from various feedstocks were presented. The concept of self-immobilized yeast cells through their flocculation is revisited through a case study of continuous ethanol fermentation with the flocculating yeast SPSC01, and their technical and economic advantages are highlighted by comparing with yeast cells immobilized with supporting materials and regular free yeast cells as well. Taking the flocculating yeast SPSC01 as an example, the ethanol tolerance of the flocculating yeast was also discussed.

  18. Energy consumption analysis of integrated flowsheets for production of fuel ethanol from lignocellulosic biomass

    International Nuclear Information System (INIS)

    Cardona Alzate, C.A.; Sanchez Toro, O.J.

    2006-01-01

    Fuel ethanol is considered one of the most important renewable fuels due to the economic and environmental benefits of its use. Lignocellulosic biomass is the most promising feedstock for producing bioethanol due to its global availability and to the energy gain that can be obtained when non-fermentable materials from biomass are used for cogeneration of heat and power. In this work, several process configurations for fuel ethanol production from lignocellulosic biomass were studied through process simulation using Aspen Plus. Some flowsheets considering the possibilities of reaction-reaction integration were taken into account among the studied process routes. The flowsheet variants were analyzed from the energy point of view utilizing as comparison criterion the energy consumption needed to produce 1 L of anhydrous ethanol. Simultaneous saccharification and cofermentation process with water recycling showed the best results accounting an energy consumption of 41.96 MJ/L EtOH. If pervaporation is used as dehydration method instead of azeotropic distillation, further energy savings can be obtained. In addition, energy balance was estimated using the results from the simulation and literature data. A net energy value of 17.65-18.93 MJ/L EtOH was calculated indicating the energy efficiency of the lignocellulosic ethanol

  19. Energy consumption analysis of integrated flowsheets for production of fuel ethanol from lignocellulosic biomass

    Energy Technology Data Exchange (ETDEWEB)

    Cardona Alzate, C.A. [Department of Chemical Engineering, National University of Colombia at Manizales, Cra. 27 No. 64-60, Manizales (Colombia)]. E-mail: ccardonaal@unal.edu.co; Sanchez Toro, O.J. [Department of Chemical Engineering, National University of Colombia at Manizales, Cra. 27 No. 64-60, Manizales (Colombia); Department of Engineering, University of Caldas, Calle 65 No. 26-10, Manizales (Colombia)

    2006-10-15

    Fuel ethanol is considered one of the most important renewable fuels due to the economic and environmental benefits of its use. Lignocellulosic biomass is the most promising feedstock for producing bioethanol due to its global availability and to the energy gain that can be obtained when non-fermentable materials from biomass are used for cogeneration of heat and power. In this work, several process configurations for fuel ethanol production from lignocellulosic biomass were studied through process simulation using Aspen Plus. Some flowsheets considering the possibilities of reaction-reaction integration were taken into account among the studied process routes. The flowsheet variants were analyzed from the energy point of view utilizing as comparison criterion the energy consumption needed to produce 1 L of anhydrous ethanol. Simultaneous saccharification and cofermentation process with water recycling showed the best results accounting an energy consumption of 41.96 MJ/L EtOH. If pervaporation is used as dehydration method instead of azeotropic distillation, further energy savings can be obtained. In addition, energy balance was estimated using the results from the simulation and literature data. A net energy value of 17.65-18.93 MJ/L EtOH was calculated indicating the energy efficiency of the lignocellulosic ethanol.

  20. Brewing characteristics of piezosensitive sake yeasts

    Science.gov (United States)

    Nomura, Kazuki; Hoshino, Hirofumi; Igoshi, Kazuaki; Onozuka, Haruka; Tanaka, Erika; Hayashi, Mayumi; Yamazaki, Harutake; Takaku, Hiroaki; Iguchi, Akinori; Shigematsu, Toru

    2018-04-01

    Application of high hydrostatic pressure (HHP) treatment to food processing is expected as a non-thermal fermentation regulation technology that supresses over fermentation. However, the yeast Saccharomyces cerevisiae used for Japanese rice wine (sake) brewing shows high tolerance to HHP. Therefore, we aimed to generate pressure-sensitive (piezosensitive) sake yeast strains by mating sake with piezosensitive yeast strains to establish an HHP fermentation regulation technology and extend the shelf life of fermented foods. The results of phenotypic analyses showed that the generated yeast strains were piezosensitive and exhibited similar fermentation ability compared with the original sake yeast strain. In addition, primary properties of sake brewed using these strains, such as ethanol concentration, sake meter value and sake flavor compounds, were almost equivalent to those obtained using the sake yeast strain. These results suggest that the piezosensitive strains exhibit brewing characteristics essentially equivalent to those of the sake yeast strain.

  1. Comparison of different pretreatment methods for lignocellulosic materials. Part I: conversion of rye straw to valuable products.

    Science.gov (United States)

    Ingram, Thomas; Wörmeyer, Kai; Lima, Juan Carlos Ixcaraguá; Bockemühl, Vera; Antranikian, Garabed; Brunner, Gerd; Smirnova, Irina

    2011-04-01

    The conversion of lignocellulose to valuable products requires I: a fractionation of the major components hemicellulose, cellulose, and lignin, II: an efficient method to process these components to higher valued products. The present work compares liquid hot water (LHW) pretreatment to the soda pulping process and to the ethanol organosolv pretreatment using rye straw as a single lignocellulosic material. The organosolv pretreated rye straw was shown to require the lowest enzyme loading in order to achieve a complete saccharification of cellulose to glucose. At biomass loadings of up to 15% (w/w) cellulose conversion of LHW and organosolv pretreated lignocellulose was found to be almost equal. The soda pulping process shows lower carbohydrate and lignin recoveries compared to the other two processes. In combination with a detailed analysis of the different lignins obtained from the three pretreatment methods, this work gives an overview of the potential products from different pretreatment processes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Hydrodynamic cavitation as a strategy to enhance the efficiency of lignocellulosic biomass pretreatment

    DEFF Research Database (Denmark)

    Terán Hilares, Ruly; Ramos, Lucas; da Silva, Silvio Silvério

    2018-01-01

    to accelerate certain chemical reactions. The application of cavitation energy to enhance the efficiency of lignocellulosic biomass pretreatment is an interesting strategy proposed for integration in biorefineries for the production of bio-based products. Moreover, the use of an HC-assisted process...... was demonstrated as an attractive alternative when compared to other conventional pretreatment technologies. This is not only due to high pretreatment efficiency resulting in high enzymatic digestibility of carbohydrate fraction, but also, by its high energy efficiency, simple configuration, and construction...... of systems, besides the possibility of using on the large scale. This paper gives an overview regarding HC technology and its potential for application on the pretreatment of lignocellulosic biomass. The parameters affecting this process and the perspectives for future developments in this area are also...

  3. Characterization of Lignocellulosic Biomass as Raw Material for the Production of Porous Carbon-based Materials

    Directory of Open Access Journals (Sweden)

    Saptadi Darmawan

    2016-02-01

    Full Text Available Lignocellulosic biomass is a potential raw material that can be used in the synthesis (manufacture of porous carbon stuffs. The properties of such porous carbon products are affected by the species of the raw material and the manufacturing process, among other things. This paper scrutinizes the related characteristics of lignocellulosic raw materials that indicate potential for the production of porous carbon. Three species were used: pine (Pinus merkusii wood, mangium (Acacia mangium wood, and candlenut (Aleurites moluccana shells, representing softwoods, hardwoods, and non-wood stuffs, respectively. Analyses of their chemical compounds and proximate contents were carried out. Additionally, nano scale scrutiny of the lignocellulosic biomass was also conducted using the nano capable instruments, which consisted of SEM, EDS, XRD, FTIR, and DSC. Results revealed that pine wood had the most potential to produce porous carbon. Morphologically, pine wood afforded the best permeability, whereby at the structure of monoclinic cellulose crystals, there were cellulose-I(alpha structures, which contained less cellulose-I(beta structures. Furthermore, pine wood exhibited greater volatile matter content, as confirmed through the FTIR, which greatly assisted the forming of porosity inside its corresponding carbon.

  4. Statistical prediction of biomethane potentials based on the composition of lignocellulosic biomass

    DEFF Research Database (Denmark)

    Thomsen, Sune Tjalfe; Spliid, Henrik; Østergård, Hanne

    2014-01-01

    Mixture models are introduced as a new and stronger methodology for statistical prediction of biomethane potentials (BPM) from lignocellulosic biomass compared to the linear regression models previously used. A large dataset from literature combined with our own data were analysed using canonical...

  5. Ethanol from lignocellulosic biomasses

    International Nuclear Information System (INIS)

    Ricci, E.; Viola, E.; Zimbardi, F.; Braccio, G.; Cuna, D.

    2001-01-01

    In this report are presented results achieved on the process optimisation of bioethanol production from wheat straw, carried out within the ENEA's project of biomass exploitation for renewable energy. The process consists of three main steps: 1) biomass pretreatment by means of steam explosion; 2) enzymatic hydrolysis of the cellulose fraction; 3) fermentation of glucose. To perform the hydrolysis step, two commercial enzymatic mixtures have been employed, mainly composed by β-glucosidase (cellobiase), endo-glucanase and exo-glucanase. The ethanologenic yeast Saccharomyces cerevisiae has been used to ferment the glucose in he hydrolyzates. Hydrolysis yield of 97% has been obtained with steam exploded wheat straw treated at 220 0 C for 3 minutes and an enzyme to substrate ratio of 4%. It has been pointed out the necessity of washing with water the pretreated what straw, in order to remove the biomass degradation products, which have shown an inhibition effect on the yeast. At the best process conditions, a fermentation yield of 95% has been achieved. In the Simultaneous Saccharification and Fermentation process, a global conversion of 92% has been obtained, which corresponds to the production of about 170 grams of ethanol per kilogram of exploded straw [it

  6. Production of Food Grade Yeasts

    Directory of Open Access Journals (Sweden)

    Argyro Bekatorou

    2006-01-01

    Full Text Available Yeasts have been known to humans for thousands of years as they have been used in traditional fermentation processes like wine, beer and bread making. Today, yeasts are also used as alternative sources of high nutritional value proteins, enzymes and vitamins, and have numerous applications in the health food industry as food additives, conditioners and flavouring agents, for the production of microbiology media and extracts, as well as livestock feeds. Modern scientific advances allow the isolation, construction and industrial production of new yeast strains to satisfy the specific demands of the food industry. Types of commercial food grade yeasts, industrial production processes and raw materials are highlighted. Aspects of yeast metabolism, with respect to carbohydrate utilization, nutritional aspects and recent research advances are also discussed.

  7. Properties of epoxide hydrolase from the yeast Rhodotorula glutinis

    NARCIS (Netherlands)

    Ariës-Kronenburg, N.A.E.

    2002-01-01

    Epoxide hydrolases are ubiquitous enzymes that can be found in nearly all living organisms. Some of the enzymes play an important role in detoxifying xenobiotic and metabolic compounds. Others are important in the growth of organisms like

  8. Intake and digestibility of diets containing castor bean meal detoxified to finish of sheep Consumo e digestibilidade de dietas contendo farelo de mamona destoxificado para ovinos em terminação

    Directory of Open Access Journals (Sweden)

    Marcônio Martins Rodrigues

    2011-03-01

    Full Text Available The effect of including detoxified castor bean meal to substitute soy bean meal was evaluated to sheep finishing diets on intake, digestibility and energy value of the diets. A positive linear effect was verified for ether extract intake and acid detergent fiber with an intake raise of 0.015 g/BW0.75 in ether extract and 0.090 g/BW0.75 in acid detergent fiber per each unit percentage of detoxified castor bean meal added to the diet. There was maximun value in hemicellulose intake when included 39.55% of detoxified castor bean meal to the diet. Negative linear effect was verified for dry matter, organic matter, crude protein, total carbohydrates digestibility, respectively, with 0.0536, 0.0507, 0.0705 and 0.0572% decreases per unit percentage of detoxified castor bean meal added. Positive quadratic effect was verified for neutral detergent fiber and hemicellulose digestibility with 54.93 and 64.53% maximum in levels of the 38.6 and 31.4, respectively. Detoxified castor bean meal inclusion does not influence dry matter and nutrients intake, attending these animal class nutritional requirements. Including detoxified castor bean meal decreases dry mater, organic matter, crude protein, total carbohydrates digestibility, being in this situation recommended the inclusion of to 33% in the diet by allowing high neutral detergent fiber and hemicellulose digestibility. Despite these effects, the energy value of the diets is not influenced by the inclusion of detoxified castor bean meal.Avaliou-se a substituição do farelo de soja pelo farelo de mamona destoxificado em dietas para ovinos em terminação. O consumo de extrato etéreo e fibra em detergente ácido foi linear positivo, com aumento de 0,015 e 0,090g/UTM por unidade percentual de inclusão de farelo de mamona destoxificado, respectivamente. O consumo máximo de hemicelulose ocorreu para dietas que continham 39,55% de farelo de mamona destoxificado. A digestibilidade da matéria seca, mat

  9. Not your ordinary yeast: non-Saccharomyces yeasts in wine production uncovered.

    Science.gov (United States)

    Jolly, Neil P; Varela, Cristian; Pretorius, Isak S

    2014-03-01

    Saccharomyces cerevisiae and grape juice are 'natural companions' and make a happy wine marriage. However, this relationship can be enriched by allowing 'wild' non-Saccharomyces yeast to participate in a sequential manner in the early phases of grape must fermentation. However, such a triangular relationship is complex and can only be taken to 'the next level' if there are no spoilage yeast present and if the 'wine yeast' - S. cerevisiae - is able to exert its dominance in time to successfully complete the alcoholic fermentation. Winemakers apply various 'matchmaking' strategies (e.g. cellar hygiene, pH, SO2 , temperature and nutrient management) to keep 'spoilers' (e.g. Dekkera bruxellensis) at bay, and allow 'compatible' wild yeast (e.g. Torulaspora delbrueckii, Pichia kluyveri, Lachancea thermotolerans and Candida/Metschnikowia pulcherrima) to harmonize with potent S. cerevisiae wine yeast and bring the best out in wine. Mismatching can lead to a 'two is company, three is a crowd' scenario. More than 40 of the 1500 known yeast species have been isolated from grape must. In this article, we review the specific flavour-active characteristics of those non-Saccharomyces species that might play a positive role in both spontaneous and inoculated wine ferments. We seek to present 'single-species' and 'multi-species' ferments in a new light and a new context, and we raise important questions about the direction of mixed-fermentation research to address market trends regarding so-called 'natural' wines. This review also highlights that, despite the fact that most frontier research and technological developments are often focussed primarily on S. cerevisiae, non-Saccharomyces research can benefit from the techniques and knowledge developed by research on the former. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  10. Shorten fungal treatment of lignocellulosic waste with additives to improve rumen degradability

    NARCIS (Netherlands)

    Kuijk, van S.J.A.; Sonnenberg, A.S.M.; Baars, J.J.P.; Hendriks, W.H.; Cone, J.W.

    2014-01-01

    Selective lignin degrading fungi can be used as pre-treatment to make cellulose in plant cell walls accessible for rumen microbes. According to previous studies, Ceriporiopsis subvermispora and Lentinula edodes can increase the in vitro rumen degradability of lignocellulosic biomass in 7 to 8 weeks.

  11. Effect of yeast storage temperature and flour composition on fermentative activities of baker's yeast

    Directory of Open Access Journals (Sweden)

    Pejin Dušanka J.

    2009-01-01

    Full Text Available Baker's yeast is a set of living cells of Saccharomyces cerevisiae. It contains around 70-72% of water, 42-45% of proteins, around 40% of carbohydrates, around 7.5% of lipids (based on dry matter, and vitamin B-complex. On the basis of yeast cell analysis it can be concluded that yeast is a complex biological system which changes in time. The intensity of the changes depends on temperature. Yeast sample was stored at 4°C i 24°C for 12 days. During storage at 4°C, the content of total carbohydrates decreased from 48.81% to 37.50% (dry matter, whereas carbohydrate loss ranged from 40.81% to 29.28% at 24°C. The content of trehalose was 12.33% in the yeast sample stored at 4°C and 0.24% at 24°C. Loss of fermentative activity was 81.76% in the sample stored at 24°C for 12 days. The composition of five samples of 1st category flour was investigated. It was found that flours containing more reducing sugars and maltose enable higher fermentation activities. The flours with higher ash content (in the range 0.5-0.94% had higher contents of phytic acid. Higher ash and phytic contents in flour increased the yeast fermentative efficiency. In bakery industry, a range of ingredients has been applied to improve the product's quality such as surface active substances (emulsifiers, enzymes, sugars and fats. In the paper, the effect of some ingredients added to dough (margarine, saccharose, sodium chloride and malted barley on the yeast fermentative activity was studied. The mentioned ingredients were added to dough at different doses: 0.5, 1.0, 1.5 and 2.0%, flour basis. It was found that the investigated ingredients affected the fermentative activity of yeast and improved the bread quality.

  12. Exploring critical factors for fermentative hydrogen production from various types of lignocellulosic biomass

    NARCIS (Netherlands)

    Panagiotopoulos, I.; Bakker, R.; Vrije, de G.J.; Niel, van E.W.J.; Koukios, E.; Claassen, P.A.M.

    2011-01-01

    Four dilute-acid pretreated and hydrolysed lignocellulosic raw materials were evaluated as substrates for fermentative hydrogen production by Caldicellulosiruptor saccharolyticus. Their fermentability was ranked in the order: barley straw > wheat straw > corn stalk > corn cob. The content

  13. Lager Yeast Comes of Age

    Science.gov (United States)

    2014-01-01

    Alcoholic fermentations have accompanied human civilizations throughout our history. Lager yeasts have a several-century-long tradition of providing fresh beer with clean taste. The yeast strains used for lager beer fermentation have long been recognized as hybrids between two Saccharomyces species. We summarize the initial findings on this hybrid nature, the genomics/transcriptomics of lager yeasts, and established targets of strain improvements. Next-generation sequencing has provided fast access to yeast genomes. Its use in population genomics has uncovered many more hybridization events within Saccharomyces species, so that lager yeast hybrids are no longer the exception from the rule. These findings have led us to propose network evolution within Saccharomyces species. This “web of life” recognizes the ability of closely related species to exchange DNA and thus drain from a combined gene pool rather than be limited to a gene pool restricted by speciation. Within the domesticated lager yeasts, two groups, the Saaz and Frohberg groups, can be distinguished based on fermentation characteristics. Recent evidence suggests that these groups share an evolutionary history. We thus propose to refer to the Saaz group as Saccharomyces carlsbergensis and to the Frohberg group as Saccharomyces pastorianus based on their distinct genomes. New insight into the hybrid nature of lager yeast will provide novel directions for future strain improvement. PMID:25084862

  14. Detoxification of acidic biorefinery waste liquor for production of high value amino acid.

    Science.gov (United States)

    Christopher, Meera; Anusree, Murali; Mathew, Anil K; Nampoothiri, K Madhavan; Sukumaran, Rajeev Kumar; Pandey, Ashok

    2016-08-01

    The current study evaluates the detoxification of acid pretreatment liquor (APL) using adsorbent (ADS 400 & ADS 800) or ion-exchange (A-27MP & A-72MP) resins and its potential for amino acid production. The APL is generated as a by-product from the pretreatment of lignocellulosic biomass and is rich monomeric sugars as well as sugar degradation products (fermentation inhibitors) such as furfural and hydroxymethyl furfural (HMF). Of the four resins compared, ADS 800 removed approximately 85% and 60% of furfural and HMF, respectively. ADS 800 could be reused for up to six cycles after regeneration without losing its adsorption properties. The study was further extended by assessing the fermentability of detoxified APL for l-lysine production using wild and mutant strains of Corynebacterium glutamicum. The detoxified APL was superior to APL for l-lysine production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Characterization of hemicellulase and cellulase from the extremely thermophilic bacterium Caldicellulosiruptor owensensis and their potential application for bioconversion of lignocellulosic biomass without pretreatment.

    Science.gov (United States)

    Peng, Xiaowei; Qiao, Weibo; Mi, Shuofu; Jia, Xiaojing; Su, Hong; Han, Yejun

    2015-01-01

    Pretreatment is currently the common approach for improving the efficiency of enzymatic hydrolysis on lignocellulose. However, the pretreatment process is expensive and will produce inhibitors such as furan derivatives and phenol derivatives. If the lignocellulosic biomass can efficiently be saccharified by enzymolysis without pretreatment, the bioconversion process would be simplified. The genus Caldicellulosiruptor, an obligatory anaerobic and extreme thermophile can produce a diverse set of glycoside hydrolases (GHs) for deconstruction of lignocellulosic biomass. It gives potential opportunities for improving the efficiency of converting native lignocellulosic biomass to fermentable sugars. Both of the extracellular (extra-) and intracellular (intra-) enzymes of C. owensensis cultivated on corncob xylan or xylose had cellulase (including endoglucanase, cellobiohydrolase and β-glucosidase) and hemicellulase (including xylanase, xylosidase, arabinofuranosidase and acetyl xylan esterase) activities. The enzymes of C. owensensis had high ability for degrading hemicellulose of native corn stover and corncob with the conversion rates of xylan 16.7 % and araban 60.0 %. Moreover, they had remarkable synergetic function with the commercial enzyme cocktail Cellic CTec2 (Novoyzmes). When the native corn stover and corncob were respectively, sequentially hydrolyzed by the extra-enzymes of C. owensensis and CTec2, the glucan conversion rates were 31.2 and 37.9 %,which were 1.7- and 1.9-fold of each control (hydrolyzed by CTec2 alone), whereas the glucan conversion rates of the steam-exploded corn stover and corncob hydrolyzed by CTec2 alone on the same loading rate were 38.2 and 39.6 %, respectively. These results show that hydrolysis by the extra-enzyme of C. owensensis made almost the same contribution as steam-exploded pretreatment on degradation of native lignocellulosic biomass. A new process for saccharification of lignocellulosic biomass by sequential hydrolysis

  16. Post-genomic analyses of fungal lignocellulosic biomass degradation reveal the unexpected potential of the plant pathogen Ustilago maydis

    Directory of Open Access Journals (Sweden)

    Couturier Marie

    2012-02-01

    Full Text Available Abstract Background Filamentous fungi are potent biomass degraders due to their ability to thrive in ligno(hemicellulose-rich environments. During the last decade, fungal genome sequencing initiatives have yielded abundant information on the genes that are putatively involved in lignocellulose degradation. At present, additional experimental studies are essential to provide insights into the fungal secreted enzymatic pools involved in lignocellulose degradation. Results In this study, we performed a wide analysis of 20 filamentous fungi for which genomic data are available to investigate their biomass-hydrolysis potential. A comparison of fungal genomes and secretomes using enzyme activity profiling revealed discrepancies in carbohydrate active enzymes (CAZymes sets dedicated to plant cell wall. Investigation of the contribution made by each secretome to the saccharification of wheat straw demonstrated that most of them individually supplemented the industrial Trichoderma reesei CL847 enzymatic cocktail. Unexpectedly, the most striking effect was obtained with the phytopathogen Ustilago maydis that improved the release of total sugars by 57% and of glucose by 22%. Proteomic analyses of the best-performing secretomes indicated a specific enzymatic mechanism of U. maydis that is likely to involve oxido-reductases and hemicellulases. Conclusion This study provides insight into the lignocellulose-degradation mechanisms by filamentous fungi and allows for the identification of a number of enzymes that are potentially useful to further improve the industrial lignocellulose bioconversion process.

  17. Yeast strains and methods of use thereof

    OpenAIRE

    Goddard, Matthew Robert; Gardner, Richard Clague; Anfang, Nicole

    2013-01-01

    The present invention relates to yeast strains and, in particular, to yeast stains for use in fermentation processes. The invention also relates to methods of fermentation using the yeast strains of the invention either alone or in combination with other yeast strains. The invention thither relates to methods for the selection of yeast strains suitable for fermentation cultures by screening for various metabolic products and the use of specific nutrient sources.

  18. Comparative evaluation of 13 yeast species in the Yarrowia clade on lignocellulosic biomass hydrolysate and genetic engineering of inhibitor tolerant strains for lipid and biofuel production

    Science.gov (United States)

    Yarrowia lipolytica is an oleaginous yeast that has garnered interest for commercial production of single cell oil and other fatty acid-derived chemicals because of its GRAS status and genetic tractability. Three recent peer-reviewed studies have highlighted the possibility of lipid production by th...

  19. Exploring the microbiota dynamics related to vegetable biomasses degradation and study of lignocellulose-degrading bacteria for industrial biotechnological application

    Science.gov (United States)

    Ventorino, Valeria; Aliberti, Alberto; Faraco, Vincenza; Robertiello, Alessandro; Giacobbe, Simona; Ercolini, Danilo; Amore, Antonella; Fagnano, Massimo; Pepe, Olimpia

    2015-02-01

    The aims of this study were to evaluate the microbial diversity of different lignocellulosic biomasses during degradation under natural conditions and to isolate, select, characterise new well-adapted bacterial strains to detect potentially improved enzyme-producing bacteria. The microbiota of biomass piles of Arundo donax, Eucalyptus camaldulensis and Populus nigra were evaluated by high-throughput sequencing. A highly complex bacterial community was found, composed of ubiquitous bacteria, with the highest representation by the Actinobacteria, Proteobacteria, Bacteroidetes and Firmicutes phyla. The abundances of the major and minor taxa retrieved during the process were determined by the selective pressure produced by the lignocellulosic plant species and degradation conditions. Moreover, cellulolytic bacteria were isolated using differential substrates and screened for cellulase, cellobiase, xylanase, pectinase and ligninase activities. Forty strains that showed multienzymatic activity were selected and identified. The highest endo-cellulase activity was seen in Promicromonospora sukumoe CE86 and Isoptericola variabilis CA84, which were able to degrade cellulose, cellobiose and xylan. Sixty-two percent of bacterial strains tested exhibited high extracellular endo-1,4-ß-glucanase activity in liquid media. These approaches show that the microbiota of lignocellulosic biomasses can be considered an important source of bacterial strains to upgrade the feasibility of lignocellulose conversion for the `greener' technology of second-generation biofuels.

  20. Immobilization of yeast cells by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Fujimura, T.; Kaetsu, I.

    1982-01-01

    Radiation-induced polymerization method was applied to the immobilization of yeast cells. The effects of irradiation, cooling and monomer, which are neccessary for polymerization, were recovered completely by subsequent aerobical incubation of yeast cells. The ethanol productive in immobilized yeast cells increased with the increase of aerobical incubation period. The growth of yeast cells in immobilized yeast cells was indicated. The maximum ethanol productivity in immobilized yeast cell system was around three times as much as that in free yeast cell system. (orig.)

  1. Evolutionary History of Ascomyceteous Yeasts

    Energy Technology Data Exchange (ETDEWEB)

    Haridas, Sajeet; Riley, Robert; Salamov, Asaf; Goker, Markus; Klenk, Hans-Peter; Kurtzman, Cletus P.; Blackwell, Meredith; Grigoriev, Igor; Jeffries, Thomas W.

    2014-06-06

    Yeasts are important for many industrial and biotechnological processes and show remarkable diversity despite morphological similarities. We have sequenced the genomes of 16 ascomycete yeasts of taxonomic and industrial importance including members of Saccharomycotina and Taphrinomycotina. A comparison of these with several other previously published yeast genomes have added increased confidence to the phylogenetic positions of previously poorly placed species including Saitoella complicata, Babjeviella inositovora and Metschnikowia bicuspidata. Phylogenetic analysis also showed that yeasts with alternative nuclear codon usage where CUG encodes serine instead of leucine are monophyletic within the Saccharomycotina. Most of the yeasts have compact genomes with a large fraction of single exon genes with Lipomyces starkeyi and the previously published Pneumocystis jirovecii being notable exceptions. Intron analysis suggests that early diverging species have more introns. We also observed a large number of unclassified lineage specific non-simple repeats in these genomes.

  2. Modelling Framework for the Identification of Critical Variables and Parameters under Uncertainty in the Bioethanol Production from Lignocellulose

    DEFF Research Database (Denmark)

    Morales Rodriguez, Ricardo; Meyer, Anne S.; Gernaey, Krist

    2011-01-01

    This study presents the development of a systematic modelling framework for identification of the most critical variables and parameters under uncertainty, evaluated on a lignocellulosic ethanol production case study. The systematic framework starts with: (1) definition of the objectives; (2......, suitable for further analysis of the bioprocess. The uncertainty and sensitivity analysis identified the following most critical variables and parameters involved in the lignocellulosic ethanol production case study. For the operating cost, the enzyme loading showed the strongest impact, while reaction...

  3. Chemical and Physicochemical Pretreatment of Lignocellulosic Biomass: A Review

    OpenAIRE

    Brodeur, Gary; Yau, Elizabeth; Badal, Kimberly; Collier, John; Ramachandran, K. B.; Ramakrishnan, Subramanian

    2011-01-01

    Overcoming the recalcitrance (resistance of plant cell walls to deconstruction) of lignocellulosic biomass is a key step in the production of fuels and chemicals. The recalcitrance is due to the highly crystalline structure of cellulose which is embedded in a matrix of polymers-lignin and hemicellulose. The main goal of pretreatment is to overcome this recalcitrance, to separate the cellulose from the matrix polymers, and to make it more accessible for enzymatic hydrolysis. Reports have sh...

  4. Sexual differentiation in fission yeast

    DEFF Research Database (Denmark)

    Egel, R; Nielsen, O; Weilguny, D

    1990-01-01

    The regulation of sexual reproduction in yeast constitutes the highest level of differentiation observed in these unicellular organisms. The various ramifications of this system involve DNA rearrangement, transcriptional control, post-translational modification (such as protein phosphorylation) a......) and receptor/signal processing. A few basic similarities are common to both fission and budding yeasts. The wiring of the regulatory circuitry, however, varies considerably between these divergent yeast groups....

  5. Occurrence of Killer Yeast Strains in Fruit and Berry Wine Yeast Populations

    Directory of Open Access Journals (Sweden)

    Gintare Gulbiniene

    2004-01-01

    Full Text Available Apple, cranberry, chokeberry and Lithuanian red grape wine yeast populations were used for the determination of killer yeast occurrence. According to the tests of the killer characteristics and immunity the isolated strains were divided into seven groups. In this work the activity of killer toxins purified from some typical strains was evaluated. The analysed strains produced different amounts of active killer toxin and some of them possessed new industrially significant killer properties. Total dsRNA extractions in 11 killer strains of yeast isolated from spontaneous fermentations revealed that the molecular basis of the killer phenomenon was not only dsRNAs, but also unidentified genetic determinants.

  6. Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines.

    Science.gov (United States)

    Roohvand, Farzin; Shokri, Mehdi; Abdollahpour-Alitappeh, Meghdad; Ehsani, Parastoo

    2017-08-01

    Yeasts, as Eukaryotes, offer unique features for ease of growth and genetic manipulation possibilities, making it an exceptional microbial host. Areas covered: This review provides general and patent-oriented insights into production of biopharmaceuticals by yeasts. Patents, wherever possible, were correlated to the original or review articles. The review describes applications of major GRAS (generally regarded as safe) yeasts for the production of therapeutic proteins and subunit vaccines; additionally, immunomodulatory properties of yeast cell wall components were reviewed for use of whole yeast cells as a new vaccine platform. The second part of the review will discuss yeast- humanization strategies and innovative applications. Expert opinion: Biomedical applications of yeasts were initiated by utilization of Saccharomyces cerevisiae, for production of leavened (fermented) products, and advanced to serve to produce biopharmaceuticals. Higher biomass production and expression/secretion yields, more similarity of glycosylation patterns to mammals and possibility of host-improvement strategies through application of synthetic biology might enhance selection of Pichia pastoris (instead of S. cerevisiae) as a host for production of biopharmaceutical in future. Immunomodulatory properties of yeast cell wall β-glucans and possibility of intracellular expression of heterologous pathogen/tumor antigens in yeast cells have expanded their application as a new platform, 'Whole Yeast Vaccines'.

  7. Thermophilic lignocellulose deconstruction.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Brown, Steven D; Sander, Kyle B; Bayer, Edward A; Kataeva, Irina; Zurawski, Jeffrey V; Conway, Jonathan M; Adams, Michael W W; Kelly, Robert M

    2014-05-01

    Thermophilic microorganisms are attractive candidates for conversion of lignocellulose to biofuels because they produce robust, effective, carbohydrate-degrading enzymes and survive under harsh bioprocessing conditions that reflect their natural biotopes. However, no naturally occurring thermophile is known that can convert plant biomass into a liquid biofuel at rates, yields and titers that meet current bioprocessing and economic targets. Meeting those targets requires either metabolically engineering solventogenic thermophiles with additional biomass-deconstruction enzymes or engineering plant biomass degraders to produce a liquid biofuel. Thermostable enzymes from microorganisms isolated from diverse environments can serve as genetic reservoirs for both efforts. Because of the sheer number of enzymes that are required to hydrolyze plant biomass to fermentable oligosaccharides, the latter strategy appears to be the preferred route and thus has received the most attention to date. Thermophilic plant biomass degraders fall into one of two categories: cellulosomal (i.e. multienzyme complexes) and noncellulosomal (i.e. 'free' enzyme systems). Plant-biomass-deconstructing thermophilic bacteria from the genera Clostridium (cellulosomal) and Caldicellulosiruptor (noncellulosomal), which have potential as metabolic engineering platforms for producing biofuels, are compared and contrasted from a systems biology perspective. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  8. Life cycle assessment of lignocellulosic ethanol: a review of key factors and methods affecting calculated GHG emissions and energy use.

    Science.gov (United States)

    Gerbrandt, Kelsey; Chu, Pei Lin; Simmonds, Allison; Mullins, Kimberley A; MacLean, Heather L; Griffin, W Michael; Saville, Bradley A

    2016-04-01

    Lignocellulosic ethanol has potential for lower life cycle greenhouse gas emissions compared to gasoline and conventional grain-based ethanol. Ethanol production 'pathways' need to meet economic and environmental goals. Numerous life cycle assessments of lignocellulosic ethanol have been published over the last 15 years, but gaps remain in understanding life cycle performance due to insufficient data, and model and methodological issues. We highlight key aspects of these issues, drawing on literature and a case study of corn stover ethanol. Challenges include the complexity of feedstock/ecosystems and market-mediated aspects and the short history of commercial lignocellulosic ethanol facilities, which collectively have led to uncertainty in GHG emissions estimates, and to debates on LCA methods and the role of uncertainty in decision making. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Pre-treatment of lignocellulosic feedstocks using biorenewable alcohols: : towards complete biomass valorisation

    NARCIS (Netherlands)

    Lancefield, Christopher S.; Panovic, Isabella; Deuss, Peter J.; Barta, Katalin; Westwood, Nicholas J.

    2017-01-01

    Here, we report on the ability of the biomass derived solvents ethanol and, in particular, n-butanol to fractionate lignocellulose into its main components. An organosolv system consisting of n-butanol containing 5% water and 0.2 M HCl at reflux was found to remove effectively the lignin and

  10. Development of a lactic acid production process using lignocellulosic biomass as feedstock

    NARCIS (Netherlands)

    Pol, van der E.C.

    2016-01-01

    The availability of crude oil is finite. Therefore, an alternative feedstock has to be found for the production of fuels and plastics. Lignocellulose is such an alternative feedstock. It is present in large quantities in agricultural waste material such as sugarcane bagasse.

    In this PhD

  11. Conceptual net energy output for biofuel production from lignocellulosic biomass through biorefining

    Science.gov (United States)

    J.Y. Zhu; X.S. Zhuang

    2012-01-01

    There is a lack of comprehensive information in the retrievable literature on pilot scale process and energy data using promising process technologies and commercially scalable and available capital equipment for lignocellulosic biomass biorefining. This study conducted a comprehensive review of the energy efficiency of selected sugar platform biorefinery process...

  12. Nitrogen amendment of green waste impacts microbial community, enzyme secretion and potential for lignocellulose decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Chaowei; Harrold, Duff R.; Claypool, Joshua T.; Simmons, Blake A.; Singer, Steven W.; Simmons, Christopher W.; VanderGheynst, Jean S.

    2017-01-01

    Microorganisms involved in biomass deconstruction are an important resource for organic waste recycling and enzymes for lignocellulose bioconversion. The goals of this paper were to examine the impact of nitrogen amendment on microbial community restructuring, secretion of xylanases and endoglucanases, and potential for biomass deconstruction. Communities were cultivated aerobically at 55 °C on green waste (GW) amended with varying levels of NH4Cl. Bacterial and fungal communities were determined using 16S rRNA and ITS region gene sequencing and PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) was applied to predict relative abundance of genes involved in lignocellulose hydrolysis. Nitrogen amendment significantly increased secretion of xylanases and endoglucanases, and microbial activity; enzyme activities and cumulative respiration were greatest when nitrogen level in GW was between 4.13–4.56 wt% (g/g), but decreased with higher nitrogen levels. The microbial community shifted to one with increasing potential to decompose complex polymers as nitrogen increased with peak potential occurring between 3.79–4.45 wt% (g/g) nitrogen amendment. Finally, the results will aid in informing the management of nitrogen level to foster microbial communities capable of secreting enzymes that hydrolyze recalcitrant polymers in lignocellulose and yield rapid decomposition of green waste.

  13. Anti-oxidative stress regulator NF-E2-related factor 2 mediates the adaptive induction of antioxidant and detoxifying enzymes by lipid peroxidation metabolite 4-hydroxynonenal

    Directory of Open Access Journals (Sweden)

    Huang Ying

    2012-11-01

    Full Text Available Abstract Background NF-E2-related factor 2 (NRF2 regulates a battery of antioxidative and phase II drug metabolizing/detoxifying genes through binding to the antioxidant response elements (ARE. NRF2-ARE signaling plays a central role in protecting cells from a wide spectrum of reactive toxic species including reactive oxygen/nitrogen species (RONS. 4-hydroxylnonenal (4-HNE is a major end product from lipid peroxidation of omega-6 polyunsaturated fatty acids (PUFA induced by oxidative stress, and it is highly reactive to nucleophilic sites in DNA and proteins, causing cytotoxicity and genotoxicity. In this study, we examined the role of NRF2 in regulating the 4-HNE induced gene expression of antioxidant and detoxifying enzymes. Results When HeLa cells were treated with 4-HNE, NRF2 rapidly transloated into the nucleus, as determined by the distribution of NRF2 tagged with the enhanced green fluorescent protein (EGFP and increased NRF2 protein in the nuclear fraction. Transcriptional activity of ARE-luciferase was significantly induced by 0.01-10 μM of 4-HNE in a dose-dependent manner, and the induction could be blocked by pretreatment with glutathione (GSH. 4-HNE induced transcriptional expression of glutathione S-transferase (GST A4, aldoketone reductase (AKR 1C1 and heme oxygenase-1 (HO-1, and the induction was attenuated by knocking down NRF2 using small interfering RNA. Conclusions NRF2 is critical in mediating 4-HNE induced expression of antioxidant and detoxifying genes. This may account for one of the major cellular defense mechanisms against reactive metabolites of lipids peroxidation induced by oxidative stress and protect cells from cytotoxicity.

  14. Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

    International Nuclear Information System (INIS)

    Lythcke-Jørgensen, Christoffer; Haglind, Fredrik; Clausen, Lasse R.

    2014-01-01

    Highlights: • We model a system where lignocellulosic ethanol production is integrated with a combined heat and power (CHP) plant. • We conduct an exergy analysis for the ethanol production in six different system operation points. • Integrated operation, district heating (DH) production and low CHP loads all increase the exergy efficiency. • Separate operation has the largest negative impact on the exergy efficiency. • Operation is found to have a significant impact on the exergy efficiency of the ethanol production. - Abstract: Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible, and a gas boiler is used as back-up when integration is not possible. The system was evaluated according to six operation points that alternate on the following three different operation parameters: Load in the CHP unit, integrated versus separate operation, and inclusion of district heating production in the ethanol facility. The calculated standard exergy efficiency of the ethanol facility varied from 0.564 to 0.855, of which the highest was obtained for integrated operation at reduced CHP load and full district heating production in the ethanol facility, and the lowest for separate operation with zero district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the

  15. Virgin olive oil yeasts: A review.

    Science.gov (United States)

    Ciafardini, Gino; Zullo, Biagi Angelo

    2018-04-01

    This review summarizes current knowledge on virgin olive oil yeasts. Newly produced olive oil contains solid particles and micro drops of vegetation water in which yeasts reproduce to become the typical microbiota of olive oil. To date, about seventeen yeast species have been isolated from different types of olive oils and their by-products, of which six species have been identified as new species. Certain yeast species contribute greatly to improving the sensorial characteristics of the newly produced olive oil, whereas other species are considered harmful as they can damage the oil quality through the production of unpleasant flavors and triacylglycerol hydrolysis. Studies carried out in certain yeast strains have demonstrated the presence of defects in olive oil treated with Candida adriatica, Nakazawaea wickerhamii and Candida diddensiae specific strains, while other olive oil samples treated with other Candida diddensiae strains were defect-free after four months of storage and categorized as extra virgin. A new acetic acid producing yeast species, namely, Brettanomyces acidodurans sp. nov., which was recently isolated from olive oil, could be implicated in the wine-vinegary defect of the product. Other aspects related to the activity of the lipase-producing yeasts and the survival of the yeast species in the flavored olive oils are also discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Pyrosequencing reveals high-temperature cellulolytic microbial consortia in Great Boiling Spring after in situ lignocellulose enrichment.

    Directory of Open Access Journals (Sweden)

    Joseph P Peacock

    Full Text Available To characterize high-temperature cellulolytic microbial communities, two lignocellulosic substrates, ammonia fiber-explosion-treated corn stover and aspen shavings, were incubated at average temperatures of 77 and 85°C in the sediment and water column of Great Boiling Spring, Nevada. Comparison of 109,941 quality-filtered 16S rRNA gene pyrosequences (pyrotags from eight enrichments to 37,057 quality-filtered pyrotags from corresponding natural samples revealed distinct enriched communities dominated by phylotypes related to cellulolytic and hemicellulolytic Thermotoga and Dictyoglomus, cellulolytic and sugar-fermenting Desulfurococcales, and sugar-fermenting and hydrogenotrophic Archaeoglobales. Minor enriched populations included close relatives of hydrogenotrophic Thermodesulfobacteria, the candidate bacterial phylum OP9, and candidate archaeal groups C2 and DHVE3. Enrichment temperature was the major factor influencing community composition, with a negative correlation between temperature and richness, followed by lignocellulosic substrate composition. This study establishes the importance of these groups in the natural degradation of lignocellulose at high temperatures and suggests that a substantial portion of the diversity of thermophiles contributing to consortial cellulolysis may be contained within lineages that have representatives in pure culture.

  17. Terroir of yeasts? – Application of FTIR spectroscopy and molecular methods for strain typing of yeasts

    Directory of Open Access Journals (Sweden)

    Gerhards Daniel

    2015-01-01

    Full Text Available The site specific influence on wine (Terroir is an often by wine producers, consumers and scientists discussed topic in the world of wine. A study on grapes and (spontaneous fermentations from six different vineyards was done to investigate the biodiversity of yeasts and to answer the question if there is a terroir of yeast and how it could be influenced. Randomly isolated yeasts were identified by FTIR-spectroscopy and molecular methods on species and strain level. Vineyard specific yeast floras would be observed but they are not such important as expected. Only a few overlapping strain patterns would be identified during both vintages. The yeast flora of the winery had a huge impact on the spontaneous fermentations, but is not really constant and influenced by different factors from outside.

  18. 21 CFR 184.1983 - Bakers yeast extract.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Bakers yeast extract. 184.1983 Section 184.1983... Listing of Specific Substances Affirmed as GRAS § 184.1983 Bakers yeast extract. (a) Bakers yeast extract... a selected strain of yeast, Saccharomyces cerevisiae. It may be concentrated or dried. (b) The...

  19. Endoplasmic reticulum involvement in yeast cell death

    International Nuclear Information System (INIS)

    Nicanor Austriaco, O.

    2012-01-01

    Yeast cells undergo programed cell death (PCD) with characteristic markers associated with apoptosis in mammalian cells including chromatin breakage, nuclear fragmentation, reactive oxygen species generation, and metacaspase activation. Though significant research has focused on mitochondrial involvement in this phenomenon, more recent work with both Saccharomyces cerevisiae and Schizosaccharomyces pombe has also implicated the endoplasmic reticulum (ER) in yeast PCD. This minireview provides an overview of ER stress-associated cell death (ER-SAD) in yeast. It begins with a description of ER structure and function in yeast before moving to a discussion of ER-SAD in both mammalian and yeast cells. Three examples of yeast cell death associated with the ER will be highlighted here including inositol starvation, lipid toxicity, and the inhibition of N-glycosylation. It closes by suggesting ways to further examine the involvement of the ER in yeast cell death.

  20. Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Zambare, Vasudeo; Zambare, Archana; Christopher, Lew P. [Center for Bioprocessing Research & Development, South Dakota School of Mines and Technology, Rapid City 57701, SD (United States); Muthukumarappan, Kasiviswanath [Center for Bioprocessing Research & Development, South Dakota State University, Brookings 57007, SD (United States)

    2011-07-01

    A thermophilic microbial consortium (TMC) producing hydrolytic (cellulolytic and xylanolytic) enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass) at 60C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover) than cellulase activity (up to 367 U/l on prairie cord grass). Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 60C and 70C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase), and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase). A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of Escherichia coli

  1. History of genome editing in yeast.

    Science.gov (United States)

    Fraczek, Marcin G; Naseeb, Samina; Delneri, Daniela

    2018-05-01

    For thousands of years humans have used the budding yeast Saccharomyces cerevisiae for the production of bread and alcohol; however, in the last 30-40 years our understanding of the yeast biology has dramatically increased, enabling us to modify its genome. Although S. cerevisiae has been the main focus of many research groups, other non-conventional yeasts have also been studied and exploited for biotechnological purposes. Our experiments and knowledge have evolved from recombination to high-throughput PCR-based transformations to highly accurate CRISPR methods in order to alter yeast traits for either research or industrial purposes. Since the release of the genome sequence of S. cerevisiae in 1996, the precise and targeted genome editing has increased significantly. In this 'Budding topic' we discuss the significant developments of genome editing in yeast, mainly focusing on Cre-loxP mediated recombination, delitto perfetto and CRISPR/Cas. © 2018 The Authors. Yeast published by John Wiley & Sons, Ltd.

  2. 21 CFR 172.898 - Bakers yeast glycan.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Bakers yeast glycan. 172.898 Section 172.898 Food... Multipurpose Additives § 172.898 Bakers yeast glycan. Bakers yeast glycan may be safely used in food in accordance with the following conditions: (a) Bakers yeast glycan is the comminuted, washed, pasteurized, and...

  3. Disruption of sugarcane bagasse lignocellulosic structure by means of dilute sulfuric acid pretreatment with microwave-assisted heating

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Tu, Yi-Jian; Sheen, Herng-Kuang

    2011-01-01

    Highlights: → Pretreatment of dilute sulfuric acid on bagasse using microwave heating. → An increase in reaction temperature destroyed bagasse significantly. → Pretreated bagasse particles were characterized by fragmentation and swelling. → When the temperature was 190 o C, the fragmentation of particles became pronounced. → The influence of heating time on bagasse structure was not significant. - Abstract: Disruption of lignocellulosic structure of biomass plays a key role in producing bioethanol from lignocelluloses. This study investigated the impact of dilute sulfuric acid pretreatment on bagasse structure using microwave heating. Three reaction temperatures of 130, 160 and 190 o C with two heating times of 5 and 10 min were considered and a number of instruments were employed to analyze the properties of the bagasse particles. On account of microwave irradiation into the solution with dielectric heating, the experiments indicated that an increase in reaction temperature destroyed the lignocellulosic structure of bagasse in a significant way. The pretreated bagasse particles were simultaneously characterized by fragmentation and swelling. When the reaction temperature was as high as 190 o C, the fragmentation of particles became fairly pronounced so that the specific surface area of the pretreated material grew substantially. Meanwhile, almost all hemicellulose was removed from bagasse and the crystalline structure of cellulose disappeared. In contrast, the feature of lignin was remained clearly. However, a comparison between the heating times of 5 and 10 min revealed that the influence of the heating time on the lignocellulosic structure was not significant, indicating that the pretreatment with 5 min was sufficiently long.

  4. The wine and beer yeast Dekkera bruxellensis.

    Science.gov (United States)

    Schifferdecker, Anna Judith; Dashko, Sofia; Ishchuk, Olena P; Piškur, Jure

    2014-09-01

    Recently, the non-conventional yeast Dekkera bruxellensis has been gaining more and more attention in the food industry and academic research. This yeast species is a distant relative of Saccharomyces cerevisiae and is especially known for two important characteristics: on the one hand, it is considered to be one of the main spoilage organisms in the wine and bioethanol industry; on the other hand, it is 'indispensable' as a contributor to the flavour profile of Belgium lambic and gueuze beers. Additionally, it adds to the characteristic aromatic properties of some red wines. Recently this yeast has also become a model for the study of yeast evolution. In this review we focus on the recently developed molecular and genetic tools, such as complete genome sequencing and transformation, to study and manipulate this yeast. We also focus on the areas that are particularly well explored in this yeast, such as the synthesis of off-flavours, yeast detection methods, carbon metabolism and evolutionary history. © 2014 The Authors. Yeast published by John Wiley & Sons, Ltd.

  5. Evaluation of biogas and syngas as energy vectors for heat and power generation using lignocellulosic biomass as raw material

    Directory of Open Access Journals (Sweden)

    Juan Camilo Solarte-Toro

    2018-05-01

    Full Text Available The use of nonrenewable energy sources to provide the worldwide energy needs has caused different problems such as global warming, water pollution, and smog production. In this sense, lignocellulosic biomass has been postulated as a renewable energy source able to produce energy carriers that can cover this energy demand. Biogas and syngas are two energy vectors that have been suggested to generate heat and power through their use in cogeneration systems. Therefore, the aim of this review is to develop a comparison between these energy vectors considering their main features based on literature reports. In addition, a techno-economic and energy assessment of the heat and power generation using these vectors as energy sources is performed. If lignocellulosic biomass is used as raw material, biogas is more commonly used for cogeneration purposes than syngas. However, syngas from biomass gasification has a great potential to be employed as a chemical platform in the production of value-added products. Moreover, the investment costs to generate heat and power from lignocellulosic materials using the anaerobic digestion technology are higher than those using the gasification technology. As a conclusion, it was evidenced that upgraded biogas has a higher potential to produce heat and power than syngas. Nevertheless, the implementation of both energy vectors into the energy market is important to cover the increasing worldwide energy demand.How to cite: Solarte-Toro JC, Chacón-Pérez Y, Cardona-Alzate CA. Evaluation of biogas and syngas as energy vectors for heat and power generation using lignocellulosic biomass as raw material. Electron J Biotechnol 2018:33. https://doi.org/10.1016/j.ejbt.2018.03.005 Keywords: Anaerobic digestion, Biogas power generation, Biomass gasification, Biomethane, Energy sources, Energy vectors, Heat generation, Lignocellulosic energy production, Power generation, Renewable energy, Syngas production

  6. Biotechnology of non-Saccharomyces yeasts-the basidiomycetes.

    Science.gov (United States)

    Johnson, Eric A

    2013-09-01

    Yeasts are the major producer of biotechnology products worldwide, exceeding production in capacity and economic revenues of other groups of industrial microorganisms. Yeasts have wide-ranging fundamental and industrial importance in scientific, food, medical, and agricultural disciplines (Fig. 1). Saccharomyces is the most important genus of yeast from fundamental and applied perspectives and has been expansively studied. Non-Saccharomyces yeasts (non-conventional yeasts) including members of the Ascomycetes and Basidiomycetes also have substantial current utility and potential applicability in biotechnology. In an earlier mini-review, "Biotechnology of non-Saccharomyces yeasts-the ascomycetes" (Johnson Appl Microb Biotechnol 97: 503-517, 2013), the extensive biotechnological utility and potential of ascomycetous yeasts are described. Ascomycetous yeasts are particularly important in food and ethanol formation, production of single-cell protein, feeds and fodder, heterologous production of proteins and enzymes, and as model and fundamental organisms for the delineation of genes and their function in mammalian and human metabolism and disease processes. In contrast, the roles of basidiomycetous yeasts in biotechnology have mainly been evaluated only in the past few decades and compared to the ascomycetous yeasts and currently have limited industrial utility. From a biotechnology perspective, the basidiomycetous yeasts are known mainly for the production of enzymes used in pharmaceutical and chemical synthesis, for production of certain classes of primary and secondary metabolites such as terpenoids and carotenoids, for aerobic catabolism of complex carbon sources, and for bioremediation of environmental pollutants and xenotoxicants. Notwithstanding, the basidiomycetous yeasts appear to have considerable potential in biotechnology owing to their catabolic utilities, formation of enzymes acting on recalcitrant substrates, and through the production of unique primary

  7. In Bacillus subtilis, the SatA (Formerly YyaR) Acetyltransferase Detoxifies Streptothricin via Lysine Acetylation.

    Science.gov (United States)

    Burckhardt, Rachel M; Escalante-Semerena, Jorge C

    2017-11-01

    Soil is a complex niche, where survival of microorganisms is at risk due to the presence of antimicrobial agents. Many microbes chemically modify cytotoxic compounds to block their deleterious effects. Streptothricin is a broad-spectrum antibiotic produced by streptomycetes that affects Gram-positive and Gram-negative bacteria alike. Here we identify the SatA (for s treptothricin a ce t yltransferase A , formerly YyaR) enzyme of Bacillus subtilis as the mechanism used by this soil bacterium to detoxify streptothricin. B. subtilis strains lacking satA were susceptible to streptothricin. Ectopic expression of satA + restored streptothricin resistance to B. subtilis satA ( Bs SatA) strains. Purified Bs SatA acetylated streptothricin in vitro at the expense of acetyl-coenzyme A (acetyl-CoA). A single acetyl moiety transferred onto streptothricin by SatA blocked the toxic effects of the antibiotic. SatA bound streptothricin with high affinity ( K d [dissociation constant] = 1 μM), and did not bind acetyl-CoA in the absence of streptothricin. Expression of B. subtilis satA + in Salmonella enterica conferred streptothricin resistance, indicating that SatA was necessary and sufficient to detoxify streptothricin. Using this heterologous system, we showed that the SatA homologue from Bacillus anthracis also had streptothricin acetyltransferase activity. Our data highlight the physiological relevance of lysine acetylation for the survival of B. subtilis in the soil. IMPORTANCE Experimental support is provided for the functional assignment of gene products of the soil-dwelling bacilli Bacillus subtilis and Bacillus anthracis This study focuses on one enzyme that is necessary and sufficient to block the cytotoxic effects of a common soil antibiotic. The enzyme alluded to is a member of a family of proteins that are broadly distributed in all domains of life but poorly studied in B. subtilis and B. anthracis The initial characterization of the enzyme provides insights into its

  8. Between science and industry-applied yeast research.

    Science.gov (United States)

    Korhola, Matti

    2018-03-01

    I was fortunate to enter yeast research at the Alko Research Laboratories with a strong tradition in yeast biochemistry and physiology studies. At the same time in the 1980s there was a fundamental or paradigm change in molecular biology research with discoveries in DNA sequencing and other analytical and physical techniques for studying macromolecules and cells. Since that time biotechnological research has expanded the traditional fermentation industries to efficient production of industrial and other enzymes and specialty chemicals. Our efforts were directed towards improving the industrial production organisms: minerals enriched yeasts (Se, Cr, Zn) and high glutathione content yeast, baker´s, distiller´s, sour dough and wine yeasts, and the fungal Trichoderma reesei platform for enzyme production. I am grateful for the trust of my colleagues in several leadership positions at the Alko Research Laboratories, Yeast Industry Platform and at the international yeast community.

  9. Saccharification of recalcitrant biomass and integration options for lignocellulosic sugars from Catchlight Energy's sugar process (CLE Sugar).

    Science.gov (United States)

    Gao, Johnway; Anderson, Dwight; Levie, Benjamin

    2013-01-28

    Woody biomass is one of the most abundant biomass feedstocks, besides agriculture residuals in the United States. The sustainable harvest residuals and thinnings alone are estimated at about 75 million tons/year. These forest residuals and thinnings could produce the equivalent of 5 billion gallons of lignocellulosic ethanol annually. Softwood biomass is the most recalcitrant biomass in pretreatment before an enzymatic hydrolysis. To utilize the most recalcitrant lignocellulosic materials, an efficient, industrially scalable and cost effective pretreatment method is needed. Obtaining a high yield of sugar from recalcitrant biomass generally requires a high severity of pretreatment with aggressive chemistry, followed by extensive conditioning, and large doses of enzymes. Catchlight Energy's Sugar process, CLE Sugar, uses a low intensity, high throughput variation of bisulfite pulping to pretreat recalcitrant biomass, such as softwood forest residuals. By leveraging well-proven bisulfite technology and the rapid progress of enzyme suppliers, CLE Sugar can achieve a high yield of total biomass carbohydrate conversion to monomeric lignocellulosic sugars. For example, 85.8% of biomass carbohydrates are saccharified for un-debarked Loblolly pine chips (softwood), and 94.0% for debarked maple chips (hardwood). Furan compound formation was 1.29% of biomass feedstock for Loblolly pine and 1.10% for maple. At 17% solids hydrolysis of pretreated softwood, an enzyme dose of 0.075 g Sigma enzyme mixture/g dry pretreated (unwashed) biomass was needed to achieve 8.1% total sugar titer in the hydrolysate and an overall prehydrolysate liquor plus enzymatic hydrolysis conversion yield of 76.6%. At a much lower enzyme dosage of 0.044 g CTec2 enzyme product/g dry (unwashed) pretreated softwood, hydrolysis at 17% solids achieved 9.2% total sugar titer in the hydrolysate with an overall sugar yield of 85.0% in the combined prehydrolysate liquor and enzymatic hydrolysate. CLE Sugar has

  10. Yeast-based biosensors: design and applications.

    Science.gov (United States)

    Adeniran, Adebola; Sherer, Michael; Tyo, Keith E J

    2015-02-01

    Yeast-based biosensing (YBB) is an exciting research area, as many studies have demonstrated the use of yeasts to accurately detect specific molecules. Biosensors incorporating various yeasts have been reported to detect an incredibly large range of molecules including but not limited to odorants, metals, intracellular metabolites, carcinogens, lactate, alcohols, and sugars. We review the detection strategies available for different types of analytes, as well as the wide range of output methods that have been incorporated with yeast biosensors. We group biosensors into two categories: those that are dependent upon transcription of a gene to report the detection of a desired molecule and those that are independent of this reporting mechanism. Transcription-dependent biosensors frequently depend on heterologous expression of sensing elements from non-yeast organisms, a strategy that has greatly expanded the range of molecules available for detection by YBBs. Transcription-independent biosensors circumvent the problem of sensing difficult-to-detect analytes by instead relying on yeast metabolism to generate easily detected molecules when the analyte is present. The use of yeast as the sensing element in biosensors has proven to be successful and continues to hold great promise for a variety of applications. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

  11. Broiler performance fed jatropha curcas seed meal detoxified by fermentation, physic and chemical treatments

    Directory of Open Access Journals (Sweden)

    Elizabeth Wina

    2010-10-01

    Full Text Available Utilization of jatropha seed meal as a feed ingredient is limited by the presence of several anti nutritive and toxic compounds in the seed meal. The aim of this research is to evaluate feeding of jatropha seed meal detoxified using fermentation by two fungi and rumen microbes (as biological detoxification and using a combination of chemical and physical treatments on broiler performance. One hundred seventy five chicks (7 days old were used and were divided into 5 treatments in 7 replications and each replication in one cage consisted of 5 chicks. R1 was control feed (K without jatropha seed meal., 2 R2 was feed with 4% of Jatropha seed meal fermented by Neurosphora sitophila (FNS, R3 was feed with 4% of Jatropha seed meal fermented by Aspergillus oryzae (FAS, R4 was feed with 4% of Jatropha seed meal fermented by rumen microbes and R5 with 4% of Jatropha seed meal treated by autoclaved, refluxed by hexane and soaked in methanol (OEHM. Treated feed was given for 14 days at the end of the feeding treatment, two chickens from each replication were slaughtered and organ weights were recorded. Body weight of chicken and feed conversion ratio were calculated. The rest of the chicken was fed commercial feed for the next 7 days (recovery periode. Chicken mortality was almost 0% but 1 chicken from FAS treatment died at the recovery period. Feed consumption was lower at fermented jatropha seed meal than control (K or OEHM, resulted in lower body weight of chicken. The abdomen fat weight and organ weights especially pancreas or spleen resulted from treatment with jatropha were much lower than that of K. In the recovery period, body weight of chicken in the OEHM treatment was almost similar from that of control chicken. In conclusion, biological detoxification on BBJ was able to reduce chicken mortality but could not improve the daily gain higher than control treatment. The best method to detoxify jatropha seed meal was the combination of physical and

  12. Enhancing biogas production from recalcitrant lignocellulosic residue

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis

    Lignocellulosic substrates are abundant in agricultural areas around the world and lately, are utilized for biogas production in full-scale anaerobic digesters. However, the anaerobic digestion (AD) of these substrates is associated with specific difficulties due to their recalcitrant nature which...... protects them from enzymatic attack. Hence, the main purpose of this work was to define diverse ways to improve the performance of AD systems using these unconventional biomasses. Thus, mechanical and thermal alkaline pretreatments, microaeration and bioaugmentation with hydrolytic microbes were examined...... conductivity, soluble chemical oxygen demand and enzymatic hydrolysis) as a rapid way to predict the methane production. However, the precision of methane yield prediction was not high (R2

  13. Prevalence of candida and non-candida yeasts isolated from patients with yeast fungal infections in Tehran labs

    Directory of Open Access Journals (Sweden)

    Hashemi SJ

    2011-04-01

    Full Text Available "n 800x600 Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} Background: Infections caused by opportunistic yeasts such as Candida species, Trichosporon, Rhodotorula and Saccharomyces have increased in immunocompromis-ed patients and their identification is crucial as intrinsic and acquired resistance of some yeast species to antifungal agents are on the rise. The aim of this study was to identify the organisms to the species level in order to suggest accurate and effective antifungal therapies."n"nMethods: In this study that carried out in Tehran, Iran in 2009, 200 patients with yeast infection were medically examined and clinical specimens were prepared for direct examination and culture on Sabouraud dextrose agar. Subsequently, the isolated yeast colonies were identified using various tests including culture on Corn Meal agar with Tween 80, CHROMagar Candida and casein agar. For the definite identification of organisms some biochemical tests were done based on carbohydrate assimilation by RapID Yeast Plus System kit, and, finally, a molecular method, PCR-RFLP, using Hpa II enzyme, was performed for the remaining unknown yeast species."n"nResults: A total of 211 yeast isolates were identified in 200 patients with yeast infections. The most frequent isolated yeasts were Candida albicans, 124 (58.77%, followed by Candida parapsilosis, 36 (17.06%, Candida tropicalis, 17 (8.06%, Candida glabrata, 13 (6.16%, Candida krusei, 8 (3.79%, Candida guilliermondii, 2 (0.96%, Trichosporon, 3 (1.14%, Rhodotorula, 1 (0.47%, Saccaromyces cerevisiae, 1 (0.47% and other

  14. Oral yeast colonization throughout pregnancy.

    Science.gov (United States)

    Rio, R; Simões-Silva, L; Garro, S; Silva, M-J; Azevedo, Á; Sampaio-Maia, B

    2017-03-01

    Recent studies suggest that placenta may harbour a unique microbiome that may have origin in maternal oral microbiome. Although the major physiological and hormonal adjustments observed in pregnant women lead to biochemical and microbiological modifications of the oral environment, very few studies evaluated the changes suffered by the oral microbiota throughout pregnancy. So, the aim of our study was to evaluate oral yeast colonization throughout pregnancy and to compare it with non-pregnant women. The oral yeast colonization was assessed in saliva of 30 pregnant and non-pregnant women longitudinally over a 6-months period. Demographic information was collected, a non-invasive intra-oral examination was performed and saliva flow and pH were determined. Pregnant and non-pregnant groups were similar regarding age and level of education. Saliva flow rate did not differ, but saliva pH was lower in pregnant than in non-pregnant women. Oral yeast prevalence was higher in pregnant than in non-pregnant women, either in the first or in the third trimester, but did not attain statistical significance. In individuals colonized with yeast, the total yeast quantification (Log10CFU/mL) increase from the 1st to the 3rd trimester in pregnant women, but not in non-pregnant women. Pregnancy may favour oral yeast growth that may be associated with an acidic oral environment.

  15. Biotechnological Applications of Dimorphic Yeasts

    Science.gov (United States)

    Doiphode, N.; Joshi, C.; Ghormade, V.; Deshpande, M. V.

    The dimorphic yeasts have the equilibrium between spherical growth (budding) and polarized (hyphal or pseudohyphal tip elongation) which can be triggered by change in the environmental conditions. The reversible growth phenomenon has made dimorphic yeasts as an useful model to understand fungal evolution and fungal differentiation, in general. In nature dimorphism is clearly evident in plant and animal fungal pathogens, which survive and most importantly proliferate in the respective hosts. However, number of organisms with no known pathogenic behaviour also show such a transition, which can be exploited for the technological applications due to their different biochemical make up under different morphologies. For instance, chitin and chitosan production using dimorphic Saccharomyces, Mucor, Rhizopus and Benjaminiella, oil degradation and biotransformation with yeast-form of Yarrowia species, bioremediation of organic pollutants, exopolysac-charide production by yeast-phase of Aureobasidium pullulans, to name a few. Myrothecium verrucaria can be used for seed dressing in its yeast form and it produces a mycolytic enzyme complex in its hyphal-form for the biocontrol of fungal pathogens, while Beauveria bassiana and other entomopathogens kill the insect pest by producing yeast- like cells in the insect body. The form-specific expression of protease, chitinase, lipase, ornithine decarboxylase, glutamate dehydrogenases, etc. make Benjaminiella poitrasii, Basidiobolus sp., and Mucor rouxii strains important in bioremediation, nanobiotechnology, fungal evolution and other areas.

  16. Electron transport chain in a thermotolerant yeast.

    Science.gov (United States)

    Mejía-Barajas, Jorge A; Martínez-Mora, José A; Salgado-Garciglia, Rafael; Noriega-Cisneros, Ruth; Ortiz-Avila, Omar; Cortés-Rojo, Christian; Saavedra-Molina, Alfredo

    2017-04-01

    Yeasts capable of growing and surviving at high temperatures are regarded as thermotolerant. For appropriate functioning of cellular processes and cell survival, the maintenance of an optimal redox state is critical of reducing and oxidizing species. We studied mitochondrial functions of the thermotolerant Kluyveromyces marxianus SLP1 and the mesophilic OFF1 yeasts, through the evaluation of its mitochondrial membrane potential (ΔΨ m ), ATPase activity, electron transport chain (ETC) activities, alternative oxidase activity, lipid peroxidation. Mitochondrial membrane potential and the cytoplasmic free Ca 2+ ions (Ca 2+ cyt) increased in the SLP1 yeast when exposed to high temperature, compared with the mesophilic yeast OFF1. ATPase activity in the mesophilic yeast diminished 80% when exposed to 40° while the thermotolerant SLP1 showed no change, despite an increase in the mitochondrial lipid peroxidation. The SLP1 thermotolerant yeast exposed to high temperature showed a diminution of 33% of the oxygen consumption in state 4. The uncoupled state 3 of oxygen consumption did not change in the mesophilic yeast when it had an increase of temperature, whereas in the thermotolerant SLP1 yeast resulted in an increase of 2.5 times when yeast were grown at 30 o , while a decrease of 51% was observed when it was exposed to high temperature. The activities of the ETC complexes were diminished in the SLP1 when exposed to high temperature, but also it was distinguished an alternative oxidase activity. Our results suggest that the mitochondria state, particularly ETC state, is an important characteristic of the thermotolerance of the SLP1 yeast strain.

  17. Investigation of adsorption kinetics and isotherm of cellulase and B-Glucosidase on lignocellulosic substrates

    Science.gov (United States)

    Clear understanding of enzyme adsorption during enzymatic hydrolysis of lignocellulosic biomass is essential to enhance the cost-efficiency of hydrolysis. However, conclusions from literatures often contradicted each other because enzyme adsorption is enzyme, biomass/pretreatment and experimental co...

  18. Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate

    Energy Technology Data Exchange (ETDEWEB)

    Binder, Thomas [Archer Daniels Midland Company, Decatur, IL (United States); Erpelding, Michael [Archer Daniels Midland Company, Decatur, IL (United States); Schmid, Josef [Archer Daniels Midland Company, Decatur, IL (United States); Chin, Andrew [Archer Daniels Midland Company, Decatur, IL (United States); Sammons, Rhea [Archer Daniels Midland Company, Decatur, IL (United States); Rockafellow, Erin [Archer Daniels Midland Company, Decatur, IL (United States)

    2015-04-10

    Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate. The purpose of Archer Daniels Midlands Integrated Biorefinery (IBR) was to demonstrate a modified acetosolv process on corn stover. It would show the fractionation of crop residue to distinct fractions of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions would be further converted to ethanol as the primary product and a fraction of the sugars would be catalytically converted to acrylic acid, with butyl acrylate the final product. These primary steps have been demonstrated.

  19. Upgrading of lignocellulosic biorefinery to value-added chemicals: Sustainability and economics of bioethanol-derivatives

    DEFF Research Database (Denmark)

    Cheali, Peam; Posada, John A.; Gernaey, Krist

    2015-01-01

    with a sustainability assessment method is used as evaluation tool. First, an existing superstructure representing the lignocellulosic biorefinery design network is extended to include the options for catalytic conversion of bioethanol to value-added derivatives. Second, the optimization problem for process upgrade...... of operating profit for biorefineries producing bioethanol-derived chemicals (247 MM$/a and 241 MM$/a for diethyl ether and 1,3-butadiene, respectively). Second, the optimal designs for upgrading bioethanol (i.e. production of 1,3-butadiene and diethyl ether) performed also better with respect...... to sustainability compared with the petroleum-based processes. In both cases, the effects of the market price uncertainties were also analyzed by performing quantitative economic risk analysis and presented a significant risk of investment for a lignocellulosic biorefinery (12 MM$/a and 92 MM$/a for diethyl ether...

  20. Interactions between Drosophila and its natural yeast symbionts-Is Saccharomyces cerevisiae a good model for studying the fly-yeast relationship?

    Science.gov (United States)

    Hoang, Don; Kopp, Artyom; Chandler, James Angus

    2015-01-01

    Yeasts play an important role in the biology of the fruit fly, Drosophila melanogaster. In addition to being a valuable source of nutrition, yeasts affect D. melanogaster behavior and interact with the host immune system. Most experiments investigating the role of yeasts in D. melanogaster biology use the baker's yeast, Saccharomyces cerevisiae. However, S. cerevisiae is rarely found with natural populations of D. melanogaster or other Drosophila species. Moreover, the strain of S. cerevisiae used most often in D. melanogaster experiments is a commercially and industrially important strain that, to the best of our knowledge, was not isolated from flies. Since disrupting natural host-microbe interactions can have profound effects on host biology, the results from D. melanogaster-S. cerevisiae laboratory experiments may not be fully representative of host-microbe interactions in nature. In this study, we explore the D. melanogaster-yeast relationship using five different strains of yeast that were isolated from wild Drosophila populations. Ingested live yeasts have variable persistence in the D. melanogaster gastrointestinal tract. For example, Hanseniaspora occidentalis persists relative to S. cerevisiae, while Brettanomyces naardenensis is removed. Despite these differences in persistence relative to S. cerevisiae, we find that all yeasts decrease in total abundance over time. Reactive oxygen species (ROS) are an important component of the D. melanogaster anti-microbial response and can inhibit S. cerevisiae growth in the intestine. To determine if sensitivity to ROS explains the differences in yeast persistence, we measured yeast growth in the presence and absence of hydrogen peroxide. We find that B. naardenesis is completely inhibited by hydrogen peroxide, while H. occidentalis is not, which is consistent with yeast sensitivity to ROS affecting persistence within the D. melanogaster gastrointestinal tract. We also compared the feeding preference of D

  1. Mechanisms Involved in the Removal of Heavy Metals from Stormwater via Lignocellulosic Filtration Media

    Science.gov (United States)

    2018-01-01

    This report aims to supplement our previous report (Yonge et al. 2016; WA-RD 816.3) that assessed copper and zinc adsorption to lignocellulosic filtration media using laboratory tests and field-scale column tests for urban stormwater remediation. The...

  2. Dynamic Simulation, Sensitivity and Uncertainty Analysis of a Demonstration Scale Lignocellulosic Enzymatic Hydrolysis Process

    DEFF Research Database (Denmark)

    Prunescu, Remus Mihail; Sin, Gürkan

    2014-01-01

    This study presents the uncertainty and sensitivity analysis of a lignocellulosic enzymatic hydrolysis model considering both model and feed parameters as sources of uncertainty. The dynamic model is parametrized for accommodating various types of biomass, and different enzymatic complexes...

  3. Thermostable, haloalkaline cellulase from Bacillus halodurans CAS 1 by conversion of lignocellulosic wastes.

    Science.gov (United States)

    Annamalai, Neelamegam; Rajeswari, Mayavan Veeramuthu; Elayaraja, Sivaramasamy; Balasubramanian, Thangavel

    2013-04-15

    An extracellular thermostable, haloalkaline cellulase by bioconversion of lignocellulosic wastes from Bacillus halodurans CAS 1 was purified to homogeneity with recovery of 12.54% and purity fold 7.96 with the molecular weight of 44 kDa. The optimum temperature, pH and NaCl for enzyme activity was determined as 60°C, 9.0 and 30% and it retained 80% of activity even at 80°C, 12 and 35% respectively. The activity was greatly inhibited by EDTA, indicating that it was a metalloenzyme and significant inhibition by PMSF revealed that serine residue was essential for catalytic activity. The purified cellulase hydrolyzed CMC, cellobiose and xylan, but not avicel, cellulose and PNPG. Furthermore, the cellulase was highly stable in the presence of detergents and organic solvents such as acetone, n-hexane and acetonitrile. Thus, the purified cellulase from B. halodurans utilizing lignocellulosic biomass could be greatly useful to develop industrial processes. Published by Elsevier Ltd.

  4. Consequences of poly(vinyl chloride) presence on the thermochemical process of lignocellulosic biomass in CO₂ by thermogravimetric analysis.

    Science.gov (United States)

    He, Yao; Ma, Xiaoqian; Zeng, Guangbo

    2015-02-01

    The thermochemical processes of lignocellulosic biomass and its mixtures with poly(vinyl chloride) (PVC) fractions were investigated by thermogravimetric analysis in CO2 atmosphere. Superposition property was assumed to examine whether and/or to what extent interactions occurred during the mixture decomposition. Results showed that interactions existed, of which the intensities changed with reaction stage, heating rate and PVC quantity, and they actively behaved toward the decomposition in most cases. With PVC presence, lignocellulosic biomass turned from three-stage to four-stage decomposition process where the reactions occurred at lower temperatures with heightened intensity, especially in the first stage. The measured activation energies calculated by Ozawa-Flynn-Wall and Vyazovkin methods were of minor difference <5 kJ/mol, and comparing them between materials in each stage confirmed the results of interaction impact. This work provides a theoretical basis bringing about the possibilities of recycling CO2 into a reaction medium of thermo-treatment of lignocellulosic material with PVC contaminants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Furfural induces reactive oxygen species accumulation and cellular damage in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Slininger Patricia J

    2010-01-01

    Full Text Available Abstract Background Biofuels offer a viable alternative to petroleum-based fuel. However, current methods are not sufficient and the technology required in order to use lignocellulosic biomass as a fermentation substrate faces several challenges. One challenge is the need for a robust fermentative microorganism that can tolerate the inhibitors present during lignocellulosic fermentation. These inhibitors include the furan aldehyde, furfural, which is released as a byproduct of pentose dehydration during the weak acid pretreatment of lignocellulose. In order to survive in the presence of furfural, yeast cells need not only to reduce furfural to the less toxic furan methanol, but also to protect themselves and repair any damage caused by the furfural. Since furfural tolerance in yeast requires a functional pentose phosphate pathway (PPP, and the PPP is associated with reactive oxygen species (ROS tolerance, we decided to investigate whether or not furfural induces ROS and its related cellular damage in yeast. Results We demonstrated that furfural induces the accumulation of ROS in Saccharomyces cerevisiae. In addition, furfural was shown to cause cellular damage that is consistent with ROS accumulation in cells which includes damage to mitochondria and vacuole membranes, the actin cytoskeleton and nuclear chromatin. The furfural-induced damage is less severe when yeast are grown in a furfural concentration (25 mM that allows for eventual growth after an extended lag compared to a concentration of furfural (50 mM that prevents growth. Conclusion These data suggest that when yeast cells encounter the inhibitor furfural, they not only need to reduce furfural into furan methanol but also to protect themselves from the cellular effects of furfural and repair any damage caused. The reduced cellular damage seen at 25 mM furfural compared to 50 mM furfural may be linked to the observation that at 25 mM furfural yeast were able to exit the furfural

  6. Feasibility study for co-locating and integrating ethanol production plants from corn starch and lignocellulosic feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibsen, Kelly [National Renewable Energy Lab. (NREL), Golden, CO (United States); McAloon, Andrew [U.S. Department of Agriculture, Washington, D.C. (United States); Yee, Winnie [U.S. Department of Agriculture, Washington, D.C. (United States)

    2005-01-01

    Analysis of the feasibility of co-locating corn-grain-to-ethanol and lignocellulosic ethanol plants and potential savings from combining utilities, ethanol purification, product processing, and fermentation.

  7. Effects of thermo-chemical pre-treatment on anaerobic biodegradability and hydrolysis of lignocellulosic biomass

    NARCIS (Netherlands)

    Fernandes, T.; Klaasse Bos, G.J.; Zeeman, G.; Sanders, J.P.M.; Lier, van J.B.

    2009-01-01

    The effects of different thermo-chemical pre-treatment methods were determined on the biodegradability and hydrolysis rate of lignocellulosic biomass. Three plant species, hay, straw and bracken were thermo-chemically pre-treated with calcium hydroxide, ammonium carbonate and maleic acid. After

  8. Genomics and the making of yeast biodiversity.

    Science.gov (United States)

    Hittinger, Chris Todd; Rokas, Antonis; Bai, Feng-Yan; Boekhout, Teun; Gonçalves, Paula; Jeffries, Thomas W; Kominek, Jacek; Lachance, Marc-André; Libkind, Diego; Rosa, Carlos A; Sampaio, José Paulo; Kurtzman, Cletus P

    2015-12-01

    Yeasts are unicellular fungi that do not form fruiting bodies. Although the yeast lifestyle has evolved multiple times, most known species belong to the subphylum Saccharomycotina (syn. Hemiascomycota, hereafter yeasts). This diverse group includes the premier eukaryotic model system, Saccharomyces cerevisiae; the common human commensal and opportunistic pathogen, Candida albicans; and over 1000 other known species (with more continuing to be discovered). Yeasts are found in every biome and continent and are more genetically diverse than angiosperms or chordates. Ease of culture, simple life cycles, and small genomes (∼10-20Mbp) have made yeasts exceptional models for molecular genetics, biotechnology, and evolutionary genomics. Here we discuss recent developments in understanding the genomic underpinnings of the making of yeast biodiversity, comparing and contrasting natural and human-associated evolutionary processes. Only a tiny fraction of yeast biodiversity and metabolic capabilities has been tapped by industry and science. Expanding the taxonomic breadth of deep genomic investigations will further illuminate how genome function evolves to encode their diverse metabolisms and ecologies. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Accelerating Yeast Prion Biology using Droplet Microfluidics

    Science.gov (United States)

    Ung, Lloyd; Rotem, Assaf; Jarosz, Daniel; Datta, Manoshi; Lindquist, Susan; Weitz, David

    2012-02-01

    Prions are infectious proteins in a misfolded form, that can induce normal proteins to take the misfolded state. Yeast prions are relevant, as a model of human prion diseases, and interesting from an evolutionary standpoint. Prions may also be a form of epigenetic inheritance, which allow yeast to adapt to stressful conditions at rates exceeding those of random mutations and propagate that adaptation to their offspring. Encapsulation of yeast in droplet microfluidic devices enables high-throughput measurements with single cell resolution, which would not be feasible using bulk methods. Millions of populations of yeast can be screened to obtain reliable measurements of prion induction and loss rates. The population dynamics of clonal yeast, when a fraction of the cells are prion expressing, can be elucidated. Furthermore, the mechanism by which certain strains of bacteria induce yeast to express prions in the wild can be deduced. Integrating the disparate fields of prion biology and droplet microfluidics reveals a more complete picture of how prions may be more than just diseases and play a functional role in yeast.

  10. Lignocellulosic Biomass Transformations via Greener Oxidative Pretreatment Processes: Access to Energy and Value-Added Chemicals.

    Science.gov (United States)

    Den, Walter; Sharma, Virender K; Lee, Mengshan; Nadadur, Govind; Varma, Rajender S

    2018-01-01

    Anthropogenic climate change, principally induced by the large volume of carbon dioxide emission from the global economy driven by fossil fuels, has been observed and scientifically proven as a major threat to civilization. Meanwhile, fossil fuel depletion has been identified as a future challenge. Lignocellulosic biomass in the form of organic residues appears to be the most promising option as renewable feedstock for the generation of energy and platform chemicals. As of today, relatively little bioenergy comes from lignocellulosic biomass as compared to feedstock such as starch and sugarcane, primarily due to high cost of production involving pretreatment steps required to fragment biomass components via disruption of the natural recalcitrant structure of these rigid polymers; low efficiency of enzymatic hydrolysis of refractory feedstock presents a major challenge. The valorization of lignin and cellulose into energy products or chemical products is contingent on the effectiveness of selective depolymerization of the pretreatment regime which typically involve harsh pyrolytic and solvothermal processes assisted by corrosive acids or alkaline reagents. These unselective methods decompose lignin into many products that may not be energetically or chemically valuable, or even biologically inhibitory. Exploring milder, selective and greener processes, therefore, has become a critical subject of study for the valorization of these materials in the last decade. Efficient alternative activation processes such as microwave- and ultrasound irradiation are being explored as replacements for pyrolysis and hydrothermolysis, while milder options such as advanced oxidative and catalytic processes should be considered as choices to harsher acid and alkaline processes. Herein, we critically abridge the research on chemical oxidative techniques for the pretreatment of lignocellulosics with the explicit aim to rationalize the objectives of the biomass pretreatment step and the

  11. Metagenomic analysis of microbial consortia enriched from compost: new insights into the role of Actinobacteria in lignocellulose decomposition.

    Science.gov (United States)

    Wang, Cheng; Dong, Da; Wang, Haoshu; Müller, Karin; Qin, Yong; Wang, Hailong; Wu, Weixiang

    2016-01-01

    Compost habitats sustain a vast ensemble of microbes specializing in the degradation of lignocellulosic plant materials and are thus important both for their roles in the global carbon cycle and as potential sources of biochemical catalysts for advanced biofuels production. Studies have revealed substantial diversity in compost microbiomes, yet how this diversity relates to functions and even to the genes encoding lignocellulolytic enzymes remains obscure. Here, we used a metagenomic analysis of the rice straw-adapted (RSA) microbial consortia enriched from compost ecosystems to decipher the systematic and functional contexts within such a distinctive microbiome. Analyses of the 16S pyrotag library and 5 Gbp of metagenomic sequence showed that the phylum Actinobacteria was the predominant group among the Bacteria in the RSA consortia, followed by Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidetes. The CAZymes profile revealed that CAZyme genes in the RSA consortia were also widely distributed within these bacterial phyla. Strikingly, about 46.1 % of CAZyme genes were from actinomycetal communities, which harbored a substantially expanded catalog of the cellobiohydrolase, β-glucosidase, acetyl xylan esterase, arabinofuranosidase, pectin lyase, and ligninase genes. Among these communities, a variety of previously unrecognized species was found, which reveals a greater ecological functional diversity of thermophilic Actinobacteria than previously assumed. These data underline the pivotal role of thermophilic Actinobacteria in lignocellulose biodegradation processes in the compost habitat. Besides revealing a new benchmark for microbial enzymatic deconstruction of lignocelluloses, the results suggest that actinomycetes found in compost ecosystems are potential candidates for mining efficient lignocellulosic enzymes in the biofuel industry.

  12. Full Data of Yeast Interacting Proteins Database (Original Version) - Yeast Interacting Proteins Database | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available List Contact us Yeast Interacting Proteins Database Full Data of Yeast Interacting Proteins Database (Origin...al Version) Data detail Data name Full Data of Yeast Interacting Proteins Database (Original Version) DOI 10....18908/lsdba.nbdc00742-004 Description of data contents The entire data in the Yeast Interacting Proteins Database...eir interactions are required. Several sources including YPD (Yeast Proteome Database, Costanzo, M. C., Hoga...ematic name in the SGD (Saccharomyces Genome Database; http://www.yeastgenome.org /). Bait gene name The gen

  13. Process Design and Economics for Biochemical Conversion of Lignocellulosic Biomass to Ethanol

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-05-02

    The U.S. Department of Energy (DOE) promotes the production of ethanol and other liquid fuels from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in the program, the National Renewable Energy Laboratory (NREL) investigates the production economics of these fuels.

  14. Determining the cost of producing ethanol from corn starch and lignocellulosic feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    McAloon, Andrew [U.S. Department of Agriculture, Washington D.C. (United States); Taylor, Frank [U.S. Department of Agriculture, Washington D.C. (United States); Yee, Winnie [U.S. Department of Agriculture, Washington D.C. (United States); Ibsen, Kelly [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wooley, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2000-10-01

    This report describes the comparison of the processes, each producing 25 million annual gallons of fuel ethanol. This paper attempts to compare the two processes as mature technologies, which requires assuming that the technology improvements needed to make the lignocellulosic process commercializable are achieved, and enough plants have been built to make the design well-understood.

  15. Mountain pine beetle-killed lodgepole pine for the production of submicron lignocellulose fibrils

    Science.gov (United States)

    Ingrid Hoeger; Rolland Gleisner; Jose Negron; Orlando J. Rojas; J. Y. Zhu

    2014-01-01

    The elevated levels of tree mortality attributed to mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) in western North American forests create forest management challenges. This investigation introduces the production of submicron or nanometer lignocellulose fibrils for value-added materials from the widely available resource represented by dead pines after...

  16. Genomics and the making of yeast biodiversity

    NARCIS (Netherlands)

    Hittinger, Chris Todd; Rokas, Antonis; Bai, Feng-Yan; Boekhout, Teun; Gonçalves, Paula; Jeffries, Thomas W; Kominek, Jacek; Lachance, Marc-André; Libkind, Diego; Rosa, Carlos A; Sampaio, José Paulo; Kurtzman, Cletus P

    2015-01-01

    Yeasts are unicellular fungi that do not form fruiting bodies. Although the yeast lifestyle has evolved multiple times, most known species belong to the subphylum Saccharomycotina (syn. Hemiascomycota, hereafter yeasts). This diverse group includes the premier eukaryotic model system, Saccharomyces

  17. High performance maleated lignocellulose epicarp fibers for copper ion removal

    OpenAIRE

    Vieira,A. P.; Santana,S. A. A.; Bezerra,C. W. B.; Silva,H. A. S.; Santos,K. C. A.; Melo,J. C. P.; Silva Filho,E. C.; Airoldi,C.

    2014-01-01

    Natural lignocellulosic fiber epicarp extracted from the babassu coconut (Orbignya speciosa) was chemically modified through reaction with molten maleic anhydride without solvent, with incorporation of 189.34 mg g(-1) of carboxylic acid groups into the biopolymer structure. The success of this reaction was also confirmed by the presence of carboxylic acid bands at 1741 and 1164 cm(-1) in the infrared spectrum. Identically, the same group is observed through C-13 NMR CP/MAS in the solid state,...

  18. Production of fuels out of lignite and lignocelluloses; Herstellung von Brennstoffen aus Braunkohle und Lignozellulose

    Energy Technology Data Exchange (ETDEWEB)

    Naundorf, W.; Schroeder, H.W.; Trommer, D. [TU Bergakademie Freiberg (Germany)

    2001-12-01

    The acceptance towards solid fuels will increase again if its ease of use is improved, the production costs remain low for extended periods of time, and high thermal efficiencies as well as low pollutant emissions are achieved. These demands can only be met by optimal fuel processing and the use of modern fuel engineering which applies, if possible, continuous and controlled fuel and air feed technology. Two fuels are introduced which are produced out of lignite and lignocelluloses by compaction or by balling granulation. Considering the improvement of combustion properties, remarkable synergy effects occur due to this raw material combination. Lignocelluloses act as an ignition auxillary. Lignite functions as a binding agent, increases the fuels' fire resistance, and guarantees a long, sustained combustion with an excellent combustion rate. (orig.)

  19. LIPID METABOLISM INDICES AND FATTY ACIDS PROFILE IN THE BLOOD SERUM OF BROILER CHICKENS FED A DIET WITH LIGNOCELLULOSE

    Directory of Open Access Journals (Sweden)

    M Bogusławska-Tryk

    Full Text Available ABSTRACT The aim of the research was to determine lipid metabolism indices and fatty acid profile in the blood serum of Ross 308 chickens (n = 48, fed a finisher mixture supplemented with 0, 0.25, 0.5 and 1.0% of lignocellulose. The feeding trial lasted from 21 to 42 d of the birds' age. Blood samples were collected from each chicken at 42d of age from the pterygoid canal vein. In the blood serum the content of triglycerides (TG, total cholesterol (TCHOL and high density lipoprotein (HDL fraction was determined by the spectrophotometric method. The fatty acids concentration was estimated with the use of the gas chromatography method. Lignocellulose in doses of 0.5 and 1.0% significantly reduced the concentration of triglycerides and low density lipoprotein (LDL fraction. Saturated fatty acids (SFA and monounsaturated fatty acids (MUFA content was not affected by dietary treatments whereas lignocellulose significantly influenced the profile of polyunsaturated fatty acids (PUFA from n-3 and n-6 families. Insoluble fiber decreased (p< 0.05 serum concentration of a-linolenic acid (C18:3n-3 and increased share of docosahexaenoic acid (C22:6n-3, dihomogammalinolenic acid (C20:3n-6 and arachidonic acid (C20:4n-6 in total PUFA, compared to the control birds. The results of the present study have shown that the incorporation of limited amounts of lignocellulose into the broiler diet can influence the lipid metabolism in the chickens.

  20. Extracellular enzyme activities during lignocellulose degradation by Streptomyces spp.: a comparative study of wild-type and genetically manipulated strains

    International Nuclear Information System (INIS)

    Ramachandra, M.; Crawford, D.L.; Pometto, A.L. III

    1987-01-01

    The wild-type ligninolytic actinomycete Streptomyces viridosporus T7A and two genetically manipulated strains with enhanced abilities to produce a water-soluble lignin degradation intermediate, an acid-precipitable polymeric lignin (APPL), were grown on lignocellulose in solid-state fermentation cultures. Culture filtrates were periodically collected, analyzed for APPL, and assayed for extracellular lignocellulose-catabolizing enzyme activities. Two APPL-overproducing strains, UV irradiation mutant T7A-81 and protoplast fusion recombinant SR-10, had higher and longer persisting peroxidase, esterase, and endoglucanase activities than did the wild-type strain T7A. Results implicated one or more of these enzymes in lignin solubilization. Only mutant T7A-81 had higher xylanase activity than the wild type. The peroxidase was induced by both lignocellulose and APPL. This extracellular enzyme has some similarities to previously described ligninases in fungi. This is the first report of such an enzyme in Streptomyces spp. Four peroxidase isozymes were present, and all catalyzed the oxidation of 3,4-dihydroxyphenylalanine, while one also catalyzed hydrogen peroxide-dependent oxidation of homoprotocatechuic acid and caffeic acid. Three constitutive esterase isozymes were produced which differed in substrate specificity toward α-naphthyl acetate and α-naphthyl butyrate. Three endoglucanase bands, which also exhibited a low level of xylanase activity, were identified on polyacrylamide gels as was one xylanase-specific band. There were no major differences in the isoenzymes produced by the different strains. The probable role of each enzyme in lignocellulose degradation is discussed

  1. Yeasts preservation: alternatives for lyophilisation

    OpenAIRE

    Nyanga, Loveness K.; Nout, Martinus J. R.; Smid, Eddy J.; Boekhout, Teun; Zwietering, Marcel H.

    2012-01-01

    The aim of the study was to compare the effect of two low-cost, low technology traditional methods for drying starter cultures with standard lyophilisation. Lyophilised yeast cultures and yeast cultures preserved in dry rice cakes and dry plant fibre strands were examined for viable cell counts during 6 months storage at 4 and 25 °C. None of the yeast cultures showed a significant loss in viable cell count during 6 months of storage at 4 °C upon lyophilisation and preservation in dry rice cak...

  2. Integrative analysis and expression profiling of secondary cell wall genes in C4 biofuel model Setaria italica reveals targets for lignocellulose bioengineering

    Directory of Open Access Journals (Sweden)

    Mehanathan eMuthamilarasan

    2015-11-01

    Full Text Available Several underutilized grasses have excellent potential for use as bioenergy feedstock due to their lignocellulosic biomass. Genomic tools have enabled identification of lignocellulose biosynthesis genes in several sequenced plants. However, the non-availability of whole genome sequence of bioenergy grasses hinders the study on bioenergy genomics and their genomics-assisted crop improvement. Foxtail millet (Setaria italica L.; Si is a model crop for studying systems biology of bioenergy grasses. In the present study, a systematic approach has been used for identification of gene families involved in cellulose (CesA/Csl, callose (Gsl and monolignol biosynthesis (PAL, C4H, 4CL, HCT, C3H, CCoAOMT, F5H, COMT, CCR, CAD and construction of physical map of foxtail millet. Sequence alignment and phylogenetic analysis of identified proteins showed that monolignol biosynthesis proteins were highly diverse, whereas CesA/Csl and Gsl proteins were homologous to rice and Arabidopsis. Comparative mapping of foxtail millet lignocellulose biosynthesis genes with other C4 panicoid genomes revealed maximum homology with switchgrass, followed by sorghum and maize. Expression profiling of candidate lignocellulose genes in response to different abiotic stresses and hormone treatments showed their differential expression pattern, with significant higher expression of SiGsl12, SiPAL2, SiHCT1, SiF5H2 and SiCAD6 genes. Further, due to the evolutionary conservation of grass genomes, the insights gained from the present study could be extrapolated for identifying genes involved in lignocellulose biosynthesis in other biofuel species for further characterization.

  3. Integrative analysis and expression profiling of secondary cell wall genes in C4 biofuel model Setaria italica reveals targets for lignocellulose bioengineering.

    Science.gov (United States)

    Muthamilarasan, Mehanathan; Khan, Yusuf; Jaishankar, Jananee; Shweta, Shweta; Lata, Charu; Prasad, Manoj

    2015-01-01

    Several underutilized grasses have excellent potential for use as bioenergy feedstock due to their lignocellulosic biomass. Genomic tools have enabled identification of lignocellulose biosynthesis genes in several sequenced plants. However, the non-availability of whole genome sequence of bioenergy grasses hinders the study on bioenergy genomics and their genomics-assisted crop improvement. Foxtail millet (Setaria italica L.; Si) is a model crop for studying systems biology of bioenergy grasses. In the present study, a systematic approach has been used for identification of gene families involved in cellulose (CesA/Csl), callose (Gsl) and monolignol biosynthesis (PAL, C4H, 4CL, HCT, C3H, CCoAOMT, F5H, COMT, CCR, CAD) and construction of physical map of foxtail millet. Sequence alignment and phylogenetic analysis of identified proteins showed that monolignol biosynthesis proteins were highly diverse, whereas CesA/Csl and Gsl proteins were homologous to rice and Arabidopsis. Comparative mapping of foxtail millet lignocellulose biosynthesis genes with other C4 panicoid genomes revealed maximum homology with switchgrass, followed by sorghum and maize. Expression profiling of candidate lignocellulose genes in response to different abiotic stresses and hormone treatments showed their differential expression pattern, with significant higher expression of SiGsl12, SiPAL2, SiHCT1, SiF5H2, and SiCAD6 genes. Further, due to the evolutionary conservation of grass genomes, the insights gained from the present study could be extrapolated for identifying genes involved in lignocellulose biosynthesis in other biofuel species for further characterization.

  4. Sugar-rich sweet sorghum is distinctively affected by wall polymer features for biomass digestibility and ethanol fermentation in bagasse.

    Science.gov (United States)

    Li, Meng; Feng, Shengqiu; Wu, Leiming; Li, Ying; Fan, Chunfen; Zhang, Rui; Zou, Weihua; Tu, Yuanyuan; Jing, Hai-Chun; Li, Shizhong; Peng, Liangcai

    2014-09-01

    Sweet sorghum has been regarded as a typical species for rich soluble-sugar and high lignocellulose residues, but their effects on biomass digestibility remain unclear. In this study, we examined total 63 representative sweet sorghum accessions that displayed a varied sugar level at stalk and diverse cell wall composition at bagasse. Correlative analysis showed that both soluble-sugar and dry-bagasse could not significantly affect lignocellulose saccharification under chemical pretreatments. Comparative analyses of five typical pairs of samples indicated that DP of crystalline cellulose and arabinose substitution degree of non-KOH-extractable hemicelluloses distinctively affected lignocellulose crystallinity for high biomass digestibility. By comparison, lignin could not alter lignocellulose crystallinity, but the KOH-extractable G-monomer predominately determined lignin negative impacts on biomass digestions, and the G-levels released from pretreatments significantly inhibited yeast fermentation. The results also suggested potential genetic approaches for enhancing soluble-sugar level and lignocellulose digestibility and reducing ethanol conversion inhibition in sweet sorghum. Copyright © 2014. Published by Elsevier Ltd.

  5. Yeasts Diversity in Fermented Foods and Beverages

    Science.gov (United States)

    Tamang, Jyoti Prakash; Fleet, Graham H.

    People across the world have learnt to culture and use the essential microorganisms for production of fermented foods and alcoholic beverages. A fermented food is produced either spontaneously or by adding mixed/pure starter culture(s). Yeasts are among the essential functional microorganisms encountered in many fermented foods, and are commercially used in production of baker's yeast, breads, wine, beer, cheese, etc. In Asia, moulds are predominant followed by amylolytic and alcohol-producing yeasts in the fermentation processes, whereas in Africa, Europe, Australia and America, fermented products are prepared exclusively using bacteria or bacteria-yeasts mixed cultures. This chapter would focus on the varieties of fermented foods and alcoholic beverages produced by yeasts, their microbiology and role in food fermentation, widely used commercial starters (pilot production, molecular aspects), production technology of some common commercial fermented foods and alcoholic beverages, toxicity and food safety using yeasts cultures and socio-economy

  6. The Effect of Aqueous Ammonia Soaking Pretreatment on Methane Generation Using Different Lignocellulosic Biomasses

    DEFF Research Database (Denmark)

    Antonopoulou, Georgia; Gavala, Hariklia N.; Skiadas, Ioannis

    2015-01-01

    In the present study aqueous ammonia soaking (AAS) has been tested as a pretreatment method for the anaerobic digestion of three lignocellulosic biomasses of different origin: one agricultural residue: sunflower straw, one perennial crop: grass and a hardwood: poplar sawdust.The methane production...

  7. Detoxifying antitumoral drugs via nanoconjugation: the case of gold nanoparticles and cisplatin.

    Directory of Open Access Journals (Sweden)

    Joan Comenge

    Full Text Available Nanoparticles (NPs have emerged as a potential tool to improve cancer treatment. Among the proposed uses in imaging and therapy, their use as a drug delivery scaffold has been extensively highlighted. However, there are still some controversial points which need a deeper understanding before clinical application can occur. Here the use of gold nanoparticles (AuNPs to detoxify the antitumoral agent cisplatin, linked to a nanoparticle via a pH-sensitive coordination bond for endosomal release, is presented. The NP conjugate design has important effects on pharmacokinetics, conjugate evolution and biodistribution and results in an absence of observed toxicity. Besides, AuNPs present unique opportunities as drug delivery scaffolds due to their size and surface tunability. Here we show that cisplatin-induced toxicity is clearly reduced without affecting the therapeutic benefits in mice models. The NPs not only act as carriers, but also protect the drug from deactivation by plasma proteins until conjugates are internalized in cells and cisplatin is released. Additionally, the possibility to track the drug (Pt and vehicle (Au separately as a function of organ and time enables a better understanding of how nanocarriers are processed by the organism.

  8. Genetics of Yeasts

    Science.gov (United States)

    Querol, Amparo; Fernández-Espinar, M. Teresa; Belloch, Carmela

    The use of yeasts in biotechnology processes dates back to ancient days. Before 7000 BC, beer was produced in Sumeria. Wine was made in Assyria in 3500 BC, and ancient Rome had over 250 bakeries, which were making leavened bread by 100 BC. And milk has been made into Kefyr and Koumiss in Asia for many centuries (Demain, Phaff, & Kurtzman, 1999). However, the importance of yeast in the food and beverage industries was only realized about 1860, when their role in food manufacturing became evident.

  9. Inheritance of the yeast mitochondrial genome

    DEFF Research Database (Denmark)

    Piskur, Jure

    1994-01-01

    Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast......Mitochondrion, extrachromosomal genetics, intergenic sequences, genome size, mitochondrial DNA, petite mutation, yeast...

  10. 21 CFR 172.590 - Yeast-malt sprout extract.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Yeast-malt sprout extract. 172.590 Section 172.590... CONSUMPTION Flavoring Agents and Related Substances § 172.590 Yeast-malt sprout extract. Yeast-malt sprout... prescribed conditions: (a) The additive is produced by partial hydrolysis of yeast extract (derived from...

  11. Evaluations of cellulose accessibilities of lignocelluloses by solute exclusion and protein adsorption techniques

    Science.gov (United States)

    Q.Q. Wang; Z. He; Z. Zhu; Y.-H.P. Zhang; Y. Ni; X.L. Luo; J.Y. Zhu

    2012-01-01

    Cellulose accessibilities of a set of hornified lignocellulosic substrates derived by drying the never dried pretreated sample and a set of differently pretreated lodgepople pine substrates, were evaluated using solute exclusion and protein adsorption methods. Direct measurements of cellulase adsorption onto cellulose surface of the set of pretreated substrates were...

  12. A numerical simulation on the flow of watershed filtration reactors using lignocellulosic materials

    Science.gov (United States)

    N. Hur; B. Choi; J.S. Han; E.W. Shin; S. Min; R.M. Rowell

    2003-01-01

    Pinyon juniper, a small-diameter and underutilized (SDU) lignocellulosic material, was harvested in New Mexico, identified as Juniperus monosperma at the USDA Forest Products Laboratory, chipped, fiberized and chemically modified to remove pollutants from wastewater. This juniper species was selected as a raw material through screening test for removal of pollutants...

  13. Comet assay on tetraploid yeast cells

    DEFF Research Database (Denmark)

    Rank, Jette; Syberg, Kristian; Jensen, Klara

    2009-01-01

    Tetraploid yeast cells (Saccharomyces cerevisiae) were used in the comet assay with the intention of developing a new, fast and easy assay for detecting environmental genotoxic agents without using higher organisms. Two DNA-damaging chemicals, H2O2 and acrylamide, together with wastewater from...... three municipal treatment plants were tested for their effect on the yeast-cell DNA. The main problem with using yeast in the comet assay is the necessity to degrade the cell wall. This was achieved by using Zymolase 100 T twice during the procedure, since Zymolase 20 T did not open the cell wall....... Analytical problems that arose due to the small amount of DNA in the yeast nuclei in haploid and diploid cells, which contain 13 Mbp and 26 Mbp DNA per cell, respectively, were solved by using tetraploid yeast cells (52 Mbp) instead. DNA damage was shown after exposure to H2O2 and acrylamide. The lowest dose...

  14. Revaluation of Waste Yeast from Beer Production

    Directory of Open Access Journals (Sweden)

    Nicoleta Suruceanu

    2013-11-01

    Full Text Available Brewing yeast is an important waste product from beer production. The valorification of slurry yeast mainly consists of separation of vitamins and important nitrogen compounds. The hops compounds, one of the most important raw materials in beer technology are removed beforehand valorification. The prenylflavonoids compounds from hops are important bioactive compounds that can be revaluation with proper technology. Revaluation of prenylflavonoids from waste yeast into dietary supplement, identification and quantification of xanthohumol by HPLC method. Waste yeast from brewery pilot plant of USAMV Cluj Napoca it was dried by atomization and the powder was analyzed on xanthohumol content by HPLC method. For quantification a calibration curve it was used. The process of drying by atomisation lead to a powder product. It was used malt dextrin powder for stabilisation. The final product it was encapsulated. The xanthohumol content of powdered yeast it was 1.94 µg/ml. In conclusion the slurry yeast from beer production it is an important source of prenylflavonoids compounds.

  15. Biomass conversion inhibitors furfural and 5-hydroxymethylfurfural induce formation of messenger RNP granules and attenuate translation activity in Saccharomyces cerevisiae.

    Science.gov (United States)

    Iwaki, Aya; Kawai, Takao; Yamamoto, Yosuke; Izawa, Shingo

    2013-03-01

    Various forms of stress can cause an attenuation of bulk translation activity and the accumulation of nontranslating mRNAs into cytoplasmic messenger RNP (mRNP) granules termed processing bodies (P-bodies) and stress granules (SGs) in eukaryotic cells. Furfural and 5-hydroxymethylfurfural (HMF), derived from lignocellulosic biomass, inhibit yeast growth and fermentation as stressors. Since there is no report regarding their effects on the formation of cytoplasmic mRNP granules, here we investigated whether furfural and HMF cause the assembly of yeast P-bodies and SGs accompanied by translational repression. We found that furfural and HMF cause the attenuation of bulk translation activity and the assembly of cytoplasmic mRNP granules in Saccharomyces cerevisiae. Notably, a combination of furfural and HMF induced the remarkable repression of translation initiation and SG formation. These findings provide new information about the physiological effects of furfural and HMF on yeast cells, and also suggest the potential usefulness of cytoplasmic mRNP granules as a warning sign or index of the deterioration of cellular physiological status in the fermentation of lignocellulosic hydrolysates.

  16. Ethanol production from xylose in engineered Saccharomyces cerevisiae strains. Current state and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Matsushika, Akinori; Inoue, Hiroyuki; Sawayama, Shigeki [National Inst. of Advanced Industrial Science and Technology (AIST), Hiroshima (JP). Biomass Technology Research Center (BTRC); Kodaki, Tsutomu [Kyoto Univ. (Japan). Inst. of Advanced Energy

    2009-08-15

    Bioethanol production from xylose is important for utilization of lignocellulosic biomass as raw materials. The research on yeast conversion of xylose to ethanol has been intensively studied especially for genetically engineered Saccharomyces cerevisiae during the last 20 years. S. cerevisiae, which is a very safe microorganism that plays a traditional and major role in industrial bioethanol production, has several advantages due to its high ethanol productivity, as well as its high ethanol and inhibitor tolerance. However, this yeast cannot ferment xylose, which is the dominant pentose sugar in hydrolysates of lignocellulosic biomass. A number of different strategies have been applied to engineer yeasts capable of efficiently producing ethanol from xylose, including the introduction of initial xylose metabolism and xylose transport, changing the intracellular redox balance, and overexpression of xylulokinase and pentose phosphate pathways. In this review, recent progress with regard to these studies is discussed, focusing particularly on xylose-fermenting strains of S. cerevisiae. Recent studies using several promising approaches such as host strain selection and adaptation to obtain further improved xylose-utilizing S. cerevisiae are also addressed. (orig.)

  17. Aboveground Deadwood Deposition Supports Development of Soil Yeasts

    Directory of Open Access Journals (Sweden)

    Thorsten Wehde

    2012-12-01

    Full Text Available Unicellular saprobic fungi (yeasts inhabit soils worldwide. Although yeast species typically occupy defined areas on the biome scale, their distribution patterns within a single type of vegetation, such as forests, are more complex. In order to understand factors that shape soil yeast communities, soils collected underneath decaying wood logs and under forest litter were analyzed. We isolated and identified molecularly a total of 25 yeast species, including three new species. Occurrence and distribution of yeasts isolated from these soils provide new insights into ecology and niche specialization of several soil-borne species. Although abundance of typical soil yeast species varied among experimental plots, the analysis of species abundance and community composition revealed a strong influence of wood log deposition and leakage of organic carbon. Unlike soils underneath logs, yeast communities in adjacent areas harbored a considerable number of transient (phylloplane-related yeasts reaching 30% of the total yeast quantity. We showed that distinguishing autochthonous community members and species transient in soils is essential to estimate appropriate effects of environmental factors on soil fungi. Furthermore, a better understanding of species niches is crucial for analyses of culture-independent data, and may hint to the discovery of unifying patterns of microbial species distribution.

  18. [Distiller Yeasts Producing Antibacterial Peptides].

    Science.gov (United States)

    Klyachko, E V; Morozkina, E V; Zaitchik, B Ts; Benevolensky, S V

    2015-01-01

    A new method of controlling lactic acid bacteria contamination was developed with the use of recombinant Saccharomyces cerevisiae strains producing antibacterial peptides. Genes encoding the antibacterial peptides pediocin and plantaricin with codons preferable for S. cerevisiae were synthesized, and a system was constructed for their secretory expression. Recombinant S. cerevisiae strains producing antibacterial peptides effectively inhibit the growth of Lactobacillus sakei, Pediacoccus pentasaceus, Pediacoccus acidilactici, etc. The application of distiller yeasts producing antibacterial peptides enhances the ethanol yield in cases of bacterial contamination. Recombinant yeasts producing the antibacterial peptides pediocin and plantaricin can successfully substitute the available industrial yeast strains upon ethanol production.

  19. Made for Each Other: Ascomycete Yeasts and Insects.

    Science.gov (United States)

    Blackwell, Meredith

    2017-06-01

    Fungi and insects live together in the same habitats, and many species of both groups rely on each other for success. Insects, the most successful animals on Earth, cannot produce sterols, essential vitamins, and many enzymes; fungi, often yeast-like in growth form, make up for these deficits. Fungi, however, require constantly replenished substrates because they consume the previous ones, and insects, sometimes lured by volatile fungal compounds, carry fungi directly to a similar, but fresh, habitat. Yeasts associated with insects include Ascomycota (Saccharomycotina, Pezizomycotina) and a few Basidiomycota. Beetles, homopterans, and flies are important associates of fungi, and in turn the insects carry yeasts in pits, specialized external pouches, and modified gut pockets. Some yeasts undergo sexual reproduction within the insect gut, where the genetic diversity of the population is increased, while others, well suited to their stable environment, may never mate. The range of interactions extends from dispersal of yeasts on the surface of insects (e.g., cactus- Drosophila -yeast and ephemeral flower communities, ambrosia beetles, yeasts with holdfasts) to extremely specialized associations of organisms that can no longer exist independently, as in the case of yeast-like symbionts of planthoppers. In a few cases yeast-like fungus-insect associations threaten butterflies and other species with extinction. Technical advances improve discovery and identification of the fungi but also inform our understanding of the evolution of yeast-insect symbioses, although there is much more to learn.

  20. The growth of solar radiated yeast

    Energy Technology Data Exchange (ETDEWEB)

    Kraft, T.

    1995-09-01

    This researcher plans to determine if solar radiation affects the growth of yeast. The irradiated yeast was obtained from a sample exposed in space during a Space Shuttle flight of September 9-20, 1994. Further, the control groups were held at: (1) Goddard Space Flight Center (GSFC) in Greenbelt, Maryland; and (2) South Dakota School of Mines and Technology. The procedure used was based on the fact that yeast is most often used in consumable baked goods. Therefore, the yeast was incorporated into a basic Betty Crocker bread recipe. Data was collected by placing measured amounts of dough into sample containers with fifteen minute growth in height measurements collected and recorded. This researcher assumed the viability of yeast to be relative to its ability to produce carbon dioxide gas and cause the dough to rise. As all ingredients and surroundings were equal, this researcher assumed the yeast will produce the only significant difference in data collected. This researcher noted the approximate use date on all sample packages to be prior to arrival and experiment date. All dates equal, it was then assumed each would act in a similar manner of response. This assumption will allow for equally correct data collection.

  1. The growth of solar radiated yeast

    Science.gov (United States)

    Kraft, Tyrone

    1995-01-01

    This researcher plans to determine if solar radiation affects the growth of yeast. The irradiated yeast was obtained from a sample exposed in space during a Space Shuttle flight of September 9-20, 1994. Further, the control groups were held at: (1) Goddard Space Flight Center (GSFC) in Greenbelt, Maryland; and (2) South Dakota School of Mines and Technology. The procedure used was based on the fact that yeast is most often used in consumable baked goods. Therefore, the yeast was incorporated into a basic Betty Crocker bread recipe. Data was collected by placing measured amounts of dough into sample containers with fifteen minute growth in height measurements collected and recorded. This researcher assumed the viability of yeast to be relative to its ability to produce carbon dioxide gas and cause the dough to rise. As all ingredients and surroundings were equal, this researcher assumed the yeast will produce the only significant difference in data collected. This researcher noted the approximate use date on all sample packages to be prior to arrival and experiment date. All dates equal, it was then assumed each would act in a similar manner of response. This assumption will allow for equally correct data collection.

  2. Scheffersomyces cryptocercus: a new xylose-fermenting yeast associated with the gut of wood roaches and new combinations in the Sugiyamaella yeast clade.

    Science.gov (United States)

    Urbina, Hector; Frank, Robert; Blackwell, Meredith

    2013-01-01

    The gut of wood-feeding insects is a microhabitat for a specialized community of microbes, including bacteria and several groups of eukaryotes such as nematodes, parabasalids and fungi. The characterization of gut yeast communities from a variety of insects has shown that certain yeasts often are associated with the insects. The gut of wood-feeding insects is rich in ascomycete yeasts and in particular xylose-fermenting (X-F) and assimilating yeasts have been consistently present in the gut of lignicolous insects. The objective of this study was the characterization of the yeast flora from the gut of the wood roach Cryptocercus sp. (Blattodea: Cryptocercidae). Five wood roaches were collected along the Appalachian Trail near the border between Tennessee and North Carolina, USA. We isolated 18 yeast strains from the wood roaches identified as Sugiyamaella paludigena and Sugiyamaella lignohabitans, xylose-assimilating yeasts, and Scheffersomyces cryptocercus (NRRL Y-48824(T) = CBS 12658) a new species of X-F yeast. The presence of X-F and certain non X-F yeasts in the gut of the subsocial wood roach Cryptocercus sp. extends the previous findings of associations between certain ascomycete yeasts and lignicolous insects. New combinations were made for 13 asexual members of the Sugiyamaella clade.

  3. Identification of a laccase from Ganoderma lucidum CBS 229.93 having potential for enhancing cellulase catalyzed lignocellulose degradation.

    Science.gov (United States)

    Sitarz, Anna K; Mikkelsen, Jørn D; Højrup, Peter; Meyer, Anne S

    2013-12-10

    Based on a differential pre-screening of 44 white-rot fungi on a lignocellulose-supplemented minimal medium, four basidiomycetes were selected for further study: Ganoderma lucidum, Polyporus brumalis, Polyporus ciliatus and Trametes versicolor. Only G. lucidum was able to grow vividly on malt extract or minimal media supplemented with alkali lignin. When grown on malt extract or minimal medium supplemented with lignocellulose (sugar cane bagasse), the crude G. lucidum protein extract exhibited high laccase activity, ∼3U/mL toward syringaldazine. This activity was 13-17 fold higher than the corresponding activities of the crude protein extracts of P. brumalis, P. ciliatus and T. versicolor. Native PAGE electrophoresis of the crude G. lucidum extract confirmed the presence of an active laccase. The G. lucidum laccase had a molecular weight of ∼62.5kDa, and a Km value of 0.107mM (determined on ABTS). A partial amino acid sequence analysis of four short de novo sequenced peptides, defined after trypsin digest analysis using MALDI-TOF MS/MS analysis, revealed 64-100% homology to sequences in related laccases in the UniProt database, but also indicated that certain sequence stretches had low homology. Addition of the laccase-rich G. lucidum broth to lignocellulosic biomass (pretreated sugar cane bagasse) together with a state-of-the-art cellulase enzyme preparation (Cellic™CTec1) produced significantly increased cellulolytic yields, which were also better than those obtained with a T. versicolor laccase addition, indicating that the laccase from G. lucidum has unique properties that may be momentous in lignocellulosic biomass conversion. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Effect of increasing growth temperature on yeast fermentation ...

    African Journals Online (AJOL)

    The effect of increasing growth temperature on yeast fermentation was studied at approximately 5 oC intervals over a range of 18 – 37 oC, using one strain each of ale, lager and wine yeast. The ale and wine yeasts grew at all the temperatures tested, but lager yeast failed to grow at 37 oC. All these strains gave lower ...

  5. Yeasts preservation: alternatives for lyophilisation

    NARCIS (Netherlands)

    Nyanga, L.K.; Nout, M.J.R.; Smid, E.J.; Boekhout, T.; Zwietering, M.H.

    2012-01-01

    The aim of the study was to compare the effect of two low-cost, low technology traditional methods for drying starter cultures with standard lyophilisation. Lyophilised yeast cultures and yeast cultures preserved in dry rice cakes and dry plant fibre strands were examined for viable cell counts

  6. Biotechnology of non-Saccharomyces yeasts--the ascomycetes.

    Science.gov (United States)

    Johnson, Eric A

    2013-01-01

    Saccharomyces cerevisiae and several other yeast species are among the most important groups of biotechnological organisms. S. cerevisiae and closely related ascomycetous yeasts are the major producer of biotechnology products worldwide, exceeding other groups of industrial microorganisms in productivity and economic revenues. Traditional industrial attributes of the S. cerevisiae group include their primary roles in food fermentations such as beers, cider, wines, sake, distilled spirits, bakery products, cheese, sausages, and other fermented foods. Other long-standing industrial processes involving S. cerevisae yeasts are production of fuel ethanol, single-cell protein (SCP), feeds and fodder, industrial enzymes, and small molecular weight metabolites. More recently, non-Saccharomyces yeasts (non-conventional yeasts) have been utilized as industrial organisms for a variety of biotechnological roles. Non-Saccharomyces yeasts are increasingly being used as hosts for expression of proteins, biocatalysts and multi-enzyme pathways for the synthesis of fine chemicals and small molecular weight compounds of medicinal and nutritional importance. Non-Saccharomyces yeasts also have important roles in agriculture as agents of biocontrol, bioremediation, and as indicators of environmental quality. Several of these products and processes have reached commercial utility, while others are in advanced development. The objective of this mini-review is to describe processes currently used by industry and those in developmental stages and close to commercialization primarily from non-Saccharomyces yeasts with an emphasis on new opportunities. The utility of S. cerevisiae in heterologous production of selected products is also described.

  7. Dominant ectosymbiotic bacteria of cellulolytic protists in the termite gut also have the potential to digest lignocellulose.

    Science.gov (United States)

    Yuki, Masahiro; Kuwahara, Hirokazu; Shintani, Masaki; Izawa, Kazuki; Sato, Tomoyuki; Starns, David; Hongoh, Yuichi; Ohkuma, Moriya

    2015-12-01

    Wood-feeding lower termites harbour symbiotic gut protists that support the termite nutritionally by degrading recalcitrant lignocellulose. These protists themselves host specific endo- and ectosymbiotic bacteria, functions of which remain largely unknown. Here, we present draft genomes of a dominant, uncultured ectosymbiont belonging to the order Bacteroidales, 'Candidatus Symbiothrix dinenymphae', which colonizes the cell surface of the cellulolytic gut protists Dinenympha spp. We analysed four single-cell genomes of Ca. S. dinenymphae, the highest genome completeness was estimated to be 81.6-82.3% with a predicted genome size of 4.28-4.31 Mb. The genome retains genes encoding large parts of the amino acid, cofactor and nucleotide biosynthetic pathways. In addition, the genome contains genes encoding various glycoside hydrolases such as endoglucanases and hemicellulases. The genome indicates that Ca. S. dinenymphae ferments lignocellulose-derived monosaccharides to acetate, a major carbon and energy source of the host termite. We suggest that the ectosymbiont digests lignocellulose and provides nutrients to the host termites, and hypothesize that the hydrolytic activity might also function as a pretreatment for the host protist to effectively decompose the crystalline cellulose components. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  8. Lignocellulose deconstruction in the biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Bomble, Yannick J.; Lin, Chien-Yuan; Amore, Antonella; Wei, Hui; Holwerda, Evert K.; Ciesielski, Peter N.; Donohoe, Bryon S.; Decker, Stephen R.; Lynd, Lee R.; Himmel, Michael E.

    2017-12-01

    Microorganisms have evolved different and yet complementary mechanisms to degrade biomass in the biosphere. The chemical biology of lignocellulose deconstruction is a complex and intricate process that appears to vary in response to specific ecosystems. These microorganisms rely on simple to complex arrangements of glycoside hydrolases to conduct most of these polysaccharide depolymerization reactions and also, as discovered more recently, oxidative mechanisms via lytic polysaccharide monooxygenases or non-enzymatic Fenton reactions which are used to enhance deconstruction. It is now clear that these deconstruction mechanisms are often more efficient in the presence of the microorganisms. In general, a major fraction of the total plant biomass deconstruction in the biosphere results from the action of various microorganisms, primarily aerobic bacteria and fungi, as well as a variety of anaerobic bacteria. Beyond carbon recycling, specialized microorganisms interact with plants to manage nitrogen in the biosphere. Understanding the interplay between these organisms within or across ecosystems is crucial to further our grasp of chemical recycling in the biosphere and also enables optimization of the burgeoning plant-based bioeconomy.

  9. Lignocellulose deconstruction in the biosphere.

    Science.gov (United States)

    Bomble, Yannick J; Lin, Chien-Yuan; Amore, Antonella; Wei, Hui; Holwerda, Evert K; Ciesielski, Peter N; Donohoe, Bryon S; Decker, Stephen R; Lynd, Lee R; Himmel, Michael E

    2017-12-01

    Microorganisms have evolved different and yet complementary mechanisms to degrade biomass in the biosphere. The chemical biology of lignocellulose deconstruction is a complex and intricate process that appears to vary in response to specific ecosystems. These microorganisms rely on simple to complex arrangements of glycoside hydrolases to conduct most of these polysaccharide depolymerization reactions and also, as discovered more recently, oxidative mechanisms via lytic polysaccharide monooxygenases or non-enzymatic Fenton reactions which are used to enhance deconstruction. It is now clear that these deconstruction mechanisms are often more efficient in the presence of the microorganisms. In general, a major fraction of the total plant biomass deconstruction in the biosphere results from the action of various microorganisms, primarily aerobic bacteria and fungi, as well as a variety of anaerobic bacteria. Beyond carbon recycling, specialized microorganisms interact with plants to manage nitrogen in the biosphere. Understanding the interplay between these organisms within or across ecosystems is crucial to further our grasp of chemical recycling in the biosphere and also enables optimization of the burgeoning plant-based bioeconomy. Copyright © 2017. Published by Elsevier Ltd.

  10. Aromatic inhibitors derived from ammonia-pretreated lignocellulose hinder bacterial ethanologenesis by activating regulatory circuits controlling inhibitor efflux and detoxification

    Directory of Open Access Journals (Sweden)

    David H. Keating

    2014-08-01

    Full Text Available Efficient microbial conversion of lignocellulosic hydrolysates to biofuels is a key barrier to the economically viable deployment of lignocellulosic biofuels. A chief contributor to this barrier is the impact on microbial processes and energy metabolism of lignocellulose-derived inhibitors, including phenolic carboxylates, phenolic amides (for ammonia-pretreated biomass, phenolic aldehydes, and furfurals. To understand the bacterial pathways induced by inhibitors present in ammonia-pretreated biomass hydrolysates, which are less well studied than acid-pretreated biomass hydrolysates, we developed and exploited synthetic mimics of ammonia-pretreated corn stover hydrolysate (ACSH. To determine regulatory responses to the inhibitors normally present in ACSH, we measured transcript and protein levels in an Escherichia coli ethanologen using RNA-seq and quantitative proteomics during fermentation to ethanol of synthetic hydrolysates containing or lacking the inhibitors. Our study identified four major regulators mediating these responses, the MarA/SoxS/Rob network, AaeR, FrmR, and YqhC. Induction of these regulons was correlated with a reduced rate of ethanol production, buildup of pyruvate, depletion of ATP and NAD(PH, and an inhibition of xylose conversion. The aromatic aldehyde inhibitor 5-hydroxymethylfurfural appeared to be reduced to its alcohol form by the ethanologen during fermentation, whereas phenolic acid and amide inhibitors were not metabolized. Together, our findings establish that the major regulatory responses to lignocellulose-derived inhibitors are mediated by transcriptional rather than translational regulators, suggest that energy consumed for inhibitor efflux and detoxification may limit biofuel production, and identify a network of regulators for future synthetic biology efforts.

  11. Taming wild yeast: potential of conventional and nonconventional yeasts in industrial fermentations.

    Science.gov (United States)

    Steensels, Jan; Verstrepen, Kevin J

    2014-01-01

    Yeasts are the main driving force behind several industrial food fermentation processes, including the production of beer, wine, sake, bread, and chocolate. Historically, these processes developed from uncontrolled, spontaneous fermentation reactions that rely on a complex mixture of microbes present in the environment. Because such spontaneous processes are generally inconsistent and inefficient and often lead to the formation of off-flavors, most of today's industrial production utilizes defined starter cultures, often consisting of a specific domesticated strain of Saccharomyces cerevisiae, S. bayanus, or S. pastorianus. Although this practice greatly improved process consistency, efficiency, and overall quality, it also limited the sensorial complexity of the end product. In this review, we discuss how Saccharomyces yeasts were domesticated to become the main workhorse of food fermentations, and we investigate the potential and selection of nonconventional yeasts that are often found in spontaneous fermentations, such as Brettanomyces, Hanseniaspora, and Pichia spp.

  12. 2nd generation lignocellulosic bioethanol: is torrefaction a possible approach to biomass pretreatment?

    Energy Technology Data Exchange (ETDEWEB)

    Chiaramonti, David; Rizzo, Andrea Maria; Prussi, Matteo [University of Florence, CREAR - Research Centre for Renewable Energy and RE-CORD, Florence (Italy); Tedeschi, Silvana; Zimbardi, Francesco; Braccio, Giacobbe; Viola, Egidio [ENEA - Laboratory of Technology and Equipment for Bioenergy and Solar Thermal, Rotondella (Italy); Pardelli, Paolo Taddei [Spike Renewables s.r.l., Florence (Italy)

    2011-03-15

    Biomass pretreatement is a key and energy-consuming step for lignocellulosic ethanol production; it is largely responsible for the energy efficiency and economic sustainability of the process. A new approach to biomass pretreatment for the lignocellulosic bioethanol chain could be mild torrefaction. Among other effects, biomass torrefaction improves the grindability of fibrous materials, thus reducing energy demand for grinding the feedstock before hydrolysis, and opens the biomass structure, making this more accessible to enzymes for hydrolysis. The aim of the preliminary experiments carried out was to achieve a first understanding of the possibility to combine torrefaction and hydrolysis for lignocellulosic bioethanol processes, and to evaluate it in terms of sugar and ethanol yields. In addition, the possibility of hydrolyzing the torrefied biomass has not yet been proven. Biomass from olive pruning has been torrefied at different conditions, namely 180-280 C for 60-120 min, grinded and then used as substrate in hydrolysis experiments. The bioconversion has been carried out at flask scale using a mixture of cellulosolytic, hemicellulosolitic, {beta}-glucosidase enzymes, and a commercial strain of Saccharomyces cerevisiae. The experiments demonstrated that torrefied biomass can be enzymatically hydrolyzed and fermented into ethanol, with yields comparable with grinded untreated biomass and saving electrical energy. The comparison between the bioconversion yields achieved using only raw grinded biomass or torrefied and grinded biomass highlighted that: (1) mild torrefaction conditions limit sugar degradation to 5-10%; and (2) torrefied biomass does not lead to enzymatic and fermentation inhibition. Energy consumption for ethanol production has been preliminary estimated, and three different pretreatment steps, i.e., raw biomass grinding, biomass-torrefaction grinding, and steam explosion were compared. Based on preliminary results, steam explosion still has a

  13. Introducing a new breed of wine yeast: interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast and Saccharomyces mikatae.

    Science.gov (United States)

    Bellon, Jennifer R; Schmid, Frank; Capone, Dimitra L; Dunn, Barbara L; Chambers, Paul J

    2013-01-01

    Interspecific hybrids are commonplace in agriculture and horticulture; bread wheat and grapefruit are but two examples. The benefits derived from interspecific hybridisation include the potential of generating advantageous transgressive phenotypes. This paper describes the generation of a new breed of wine yeast by interspecific hybridisation between a commercial Saccharomyces cerevisiae wine yeast strain and Saccharomyces mikatae, a species hitherto not associated with industrial fermentation environs. While commercially available wine yeast strains provide consistent and reliable fermentations, wines produced using single inocula are thought to lack the sensory complexity and rounded palate structure obtained from spontaneous fermentations. In contrast, interspecific yeast hybrids have the potential to deliver increased complexity to wine sensory properties and alternative wine styles through the formation of novel, and wider ranging, yeast volatile fermentation metabolite profiles, whilst maintaining the robustness of the wine yeast parent. Screening of newly generated hybrids from a cross between a S. cerevisiae wine yeast and S. mikatae (closely-related but ecologically distant members of the Saccharomyces sensu stricto clade), has identified progeny with robust fermentation properties and winemaking potential. Chemical analysis showed that, relative to the S. cerevisiae wine yeast parent, hybrids produced wines with different concentrations of volatile metabolites that are known to contribute to wine flavour and aroma, including flavour compounds associated with non-Saccharomyces species. The new S. cerevisiae x S. mikatae hybrids have the potential to produce complex wines akin to products of spontaneous fermentation while giving winemakers the safeguard of an inoculated ferment.

  14. Ionic liquid-tolerant microorganisms and microbial communities for lignocellulose conversion to bioproducts.

    Science.gov (United States)

    Yu, Chaowei; Simmons, Blake A; Singer, Steven W; Thelen, Michael P; VanderGheynst, Jean S

    2016-12-01

    Chemical and physical pretreatment of biomass is a critical step in the conversion of lignocellulose to biofuels and bioproducts. Ionic liquid (IL) pretreatment has attracted significant attention due to the unique ability of certain ILs to solubilize some or all components of the plant cell wall. However, these ILs inhibit not only the enzyme activities but also the growth and productivity of microorganisms used in downstream hydrolysis and fermentation processes. While pretreated biomass can be washed to remove residual IL and reduce inhibition, extensive washing is costly and not feasible in large-scale processes. IL-tolerant microorganisms and microbial communities have been discovered from environmental samples and studies begun to elucidate mechanisms of IL tolerance. The discovery of IL tolerance in environmental microbial communities and individual microbes has lead to the proposal of molecular mechanisms of resistance. In this article, we review recent progress on discovering IL-tolerant microorganisms, identifying metabolic pathways and mechanisms of tolerance, and engineering microorganisms for IL tolerance. Research in these areas will yield new approaches to overcome inhibition in lignocellulosic biomass bioconversion processes and increase opportunities for the use of ILs in biomass pretreatment.

  15. Synthesis and photobactericidal properties of a neutral porphyrin grafted onto lignocellulosic fibers

    Energy Technology Data Exchange (ETDEWEB)

    Nzambe Ta keki, Jean Kerim; Ouk, Tan-Sothéa [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Zerrouki, Rachida [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Centre de Recherche sur les Matériaux Lignocellulosiques, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7 (Canada); Faugeras, Pierre-Antoine; Sol, Vincent [Laboratoire de chimie des substances naturelles, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges (France); Brouillette, François [Centre de Recherche sur les Matériaux Lignocellulosiques, Université du Québec à Trois-Rivières, 3351 boul. des Forges, C.P. 500, Trois-Rivières, QC G9A 5H7 (Canada)

    2016-05-01

    Photodynamic antimicrobial chemotherapy (PACT), as one of the promising alternative antimicrobial treatment, has received great attention in recent years. In this work, a new antimicrobial material has been elaborated by grafting a neutral porphyrin, the metallated 5-(4-azidophenyl)-10,15,20-triphenylporphyrin, onto lignocellulosic fibers by using the Copper (I)-Catalyzed Alkyne-Azide 1,3-dipolar Cycloaddition (CuAAC) reaction. The cross-linked porphyrin-Kraft pulp material was characterized by infrared and by XPS spectroscopy analyses, which proved the covalent linkage between the porphyrin and propargylated Kraft pulp fibers. The antimicrobial activity of this material was tested under visible light irradiation with a low light dose (9.5 J/cm{sup 2}) against Staphylococcus aureus and Pseudomonas aeruginosa. The two bacterial strains deposited on the resulting photosensitizing Kraft pulp are efficiently killed after illumination. Such materials could find applications in industrial, household and medical environments as an alternative to overcome the widespread microbial multiresistance to classical treatments. - Highlights: • Elaboration of new antimicrobial paper • Grafting of porphyrin on lignocellulosic fibers using click chemistry • Modification of Kraft pulp fibers, using water as solvent.

  16. Enhanced acetone-butanol-ethanol production from lignocellulosic hydrolysates by using starchy slurry as supplement.

    Science.gov (United States)

    Yang, Ming; Kuittinen, Suvi; Vepsäläinen, Jouko; Zhang, Junhua; Pappinen, Ari

    2017-11-01

    This study aims to improve acetone-butanol-ethanol production from the hydrolysates of lignocellulosic material by supplementing starchy slurry as nutrients. In the fermentations of glucose, xylose and the hydrolysates of Salix schwerinii, the normal supplements such as buffer, minerals, and vitamins solutions were replaced with the barley starchy slurry. The ABE production was increased from 0.86 to 14.7g/L by supplementation of starchy slurry in the fermentation of xylose and the utilization of xylose increased from 29% to 81%. In the fermentations of hemicellulosic and enzymatic hydrolysates from S. schwerinii, the ABE yields were increased from 0 and 0.26 to 0.35 and 0.33g/g sugars, respectively. The results suggested that the starchy slurry supplied the essential nutrients for ABE fermentation. The starchy slurry as supplement could improve the ABE production from both hemicellulosic and cellulosic hydrolysate of lignocelluloses, and it is particularly helpful for enhancing the utilization of xylose from hemicelluloses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Yeast Interacting Proteins Database: YFR015C, YFR015C [Yeast Interacting Proteins Database

    Lifescience Database Archive (English)

    Full Text Available yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental stress, and entr...ression induced by glucose limitation, nitrogen starvation, environmental stress, and entry into stationary ...tion, nitrogen starvation, environmental stress, and entry into stationary phase Rows with this bait as bait..., the more highly expressed yeast homolog; expression induced by glucose limitation, nitrogen starvation, environmental

  18. Hydrodynamic cavitation as a strategy to enhance the efficiency of lignocellulosic biomass pretreatment.

    Science.gov (United States)

    Terán Hilares, Ruly; Ramos, Lucas; da Silva, Silvio Silvério; Dragone, Giuliano; Mussatto, Solange I; Santos, Júlio César Dos

    2018-06-01

    Hydrodynamic cavitation (HC) is a process technology with potential for application in different areas including environmental, food processing, and biofuels production. Although HC is an undesirable phenomenon for hydraulic equipment, the net energy released during this process is enough to accelerate certain chemical reactions. The application of cavitation energy to enhance the efficiency of lignocellulosic biomass pretreatment is an interesting strategy proposed for integration in biorefineries for the production of bio-based products. Moreover, the use of an HC-assisted process was demonstrated as an attractive alternative when compared to other conventional pretreatment technologies. This is not only due to high pretreatment efficiency resulting in high enzymatic digestibility of carbohydrate fraction, but also, by its high energy efficiency, simple configuration, and construction of systems, besides the possibility of using on the large scale. This paper gives an overview regarding HC technology and its potential for application on the pretreatment of lignocellulosic biomass. The parameters affecting this process and the perspectives for future developments in this area are also presented and discussed.

  19. Adhesion improvement of lignocellulosic products by enzymatic pre-treatment.

    Science.gov (United States)

    Widsten, Petri; Kandelbauer, Andreas

    2008-01-01

    Enzymatic bonding methods, based on laccase or peroxidase enzymes, for lignocellulosic products such as medium-density fiberboard and particleboard are discussed with reference to the increasing costs of presently used petroleum-based adhesives and the health concerns associated with formaldehyde emissions from current composite products. One approach is to improve the self-bonding properties of the particles by oxidation of their surface lignin before they are fabricated into boards. Another method involves using enzymatically pre-treated lignins as adhesives for boards and laminates. The application of this technology to achieve wet strength characteristics in paper is also reviewed.

  20. Radiodiagnosis of yeast alveolits (a clinicoexperimental study)

    International Nuclear Information System (INIS)

    Amosov, I.S.; Smirnov, V.A.

    1984-01-01

    A clinicoroetgenological study was made of 115 workers engaged in the yeast production for different periods of time. Disorders of the respiration biomechanics were revealed depending on the period of service. These data were obtained as a result of the use of roentgenopneumopolygraphy. An experimental study was conducted to establish the nature of lesions in the bronchopulmonary system in allergic alveolitis. The effect of finely divided yeast dust on the bronchopulmonary system was studied on 132 guinea-pigs usinq microbronchography and morphological examination. As a result of the study it has been established that during the inhalation of yeast dust, notnceable dystrophy of the bronchi develops, the sizes of alveoli enlarge and part of them undergo emphysematous distension with the rupture of the interalveolar septa. In the course of the study, it has been shown that yeast dust is little agreessive, yeast alveolitis develops after many years of work. The clinical symptoms are non-specific and insignificant. X-ray and morphological changes are followed by the physical manifestations of yeast alveolitis