Yeasts in sustainable bioethanol production: A review

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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.

Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass

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Irena Kolouchová

2016-01-01

Full Text Available We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp. and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90% content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70.

Yeast flocculation: New story in fuel ethanol production.

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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.

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)

Yeast synthetic biology toolbox and applications for biofuel production.

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Tsai, Ching-Sung; Kwak, Suryang; Turner, Timothy L; Jin, Yong-Su

2015-02-01

Yeasts are efficient biofuel producers with numerous advantages outcompeting bacterial counterparts. While most synthetic biology tools have been developed and customized for bacteria especially for Escherichia coli, yeast synthetic biological tools have been exploited for improving yeast to produce fuels and chemicals from renewable biomass. Here we review the current status of synthetic biological tools and their applications for biofuel production, focusing on the model strain Saccharomyces cerevisiae We describe assembly techniques that have been developed for constructing genes, pathways, and genomes in yeast. Moreover, we discuss synthetic parts for allowing precise control of gene expression at both transcriptional and translational levels. Applications of these synthetic biological approaches have led to identification of effective gene targets that are responsible for desirable traits, such as cellulosic sugar utilization, advanced biofuel production, and enhanced tolerance against toxic products for biofuel production from renewable biomass. Although an array of synthetic biology tools and devices are available, we observed some gaps existing in tool development to achieve industrial utilization. Looking forward, future tool development should focus on industrial cultivation conditions utilizing industrial strains. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

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.

Biotransformation of vegetable and fruit processing wastes into yeast biomass enriched with selenium

Energy Technology Data Exchange (ETDEWEB)

Stabnikova, O.; Jing Yuan Wang; Hong Bo Ding; Joo Hwa Tay [Nanyang Technological Univ., Singapore (Singapore). School of Civil and Environmental Engineering

2005-04-01

Water extracts of cabbage, watermelon, a mixture of residual biomass of green salads and tropical fruits were used for yeast cultivation. These extracts contained from 1420 to 8900 mg/l of dissolved organic matter, and from 600 to 1800 mg/l of nitrogen. pH of the extracts was in the range from 4.1 to 6.4. Biomass concentration of yeast, Saccharomyces cerevisiae CEE 12 grown at 30 {sup o}C for 96 h in the sterilized extracts without any nutrient supplements was from 6.4 to 8.2 g/l; content of protein was from 40% to 45% of dry biomass. The yield was comparable with the yield of yeast biomass grown in potato dextrose broth. The biomass can be considered as the protein source. Its feed value was enhanced by incorporation of selenium in biomass to the level of 150 {mu}g/g of dry biomass. Therefore, it was recommended to transform the extracts from vegetable and fruit processing wastes into the yeast biomass enriched with selenium. (Author)

Low cost production of perdeuterated biomass using methylotrophic yeasts

International Nuclear Information System (INIS)

Haon, S.; Auge, S.; Tropis, M.; Milon, A.; Lindley, N.D.

1993-01-01

Three strains of methylotropic yeasts, Candida boidinii, Pichia angusta (previously Hansenula polymorpha) and Pichia pastoris, were studied for their capacity to grow on methanol in deuterated media. Growth rates, determined relative to the extent of deuteration of water and/or methanol, showed that water deuteration was the major limiting factor. After adaptation to deuterium by progressive transfer through media of increasing deuteration, growth rates were diminished relative to those obtained on hydrogenated media of identical salts composition: the two Pichia species retained the highest growth rates in the full deuterated medium. Perdeuterated biomass (16 g) was obtained in a 1 liter fed-batch fermentation and the extent of deuteration of isolated ergosterol has been shown to be 97.5% by mass spectrometric analysis. (Author)

Treatment and Valorization of Palm Oil Mill Effluent through Production of Food Grade Yeast Biomass

OpenAIRE

Joy O. Iwuagwu; J. Obeta Ugwuanyi

2014-01-01

Palm oil mill effluent (POME) is high strength wastewater derived from processing of palm fruit. It is generated in large quantities in all oil palm producing nations where it is a strong pollutant amenable to microbial degradation being rich in organic carbon, nitrogen, and minerals. Valorization and treatment of POME with seven yeast isolates was studied under scalable conditions by using POME to produce value-added yeast biomass. POME was used as sole source of carbon and nitrogen and the ...

Recombinant protein production facility for fungal biomass-degrading enzymes using the yeast Pichia pastoris

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Mireille eHaon

2015-09-01

Full Text Available Filamentous fungi are the predominant source of lignocellulolytic enzymes used in industry for the transformation of plant biomass into high-value molecules and biofuels. The rapidity with which new fungal genomic and post-genomic data are being produced is vastly outpacing functional studies. This underscores the critical need for developing platforms dedicated to the recombinant expression of enzymes lacking confident functional annotation, a prerequisite to their functional and structural study. In the last decade, the yeast Pichia pastoris has become increasingly popular as a host for the production of fungal biomass-degrading enzymes, and particularly carbohydrate-active enzymes (CAZymes. This study aimed at setting-up a platform to easily and quickly screen the extracellular expression of biomass-degrading enzymes in Pichia pastoris. We first used three fungal glycoside hydrolases that we previously expressed using the protocol devised by Invitrogen to try different modifications of the original protocol. Considering the gain in time and convenience provided by the new protocol, we used it as basis to set-up the facility and produce a suite of fungal CAZymes (glycoside hydrolases, carbohydrate esterases and auxiliary activity enzyme families out of which more than 70% were successfully expressed. The platform tasks range from gene cloning to automated protein purifications and activity tests, and is open to the CAZyme users’ community.

Biomedical applications of yeast- a patent view, part one: yeasts as workhorses for the production of therapeutics and vaccines.

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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'.

Detergent assisted ultrasonication aided in situ transesterification for biodiesel production from oleaginous yeast wet biomass.

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Yellapu, Sravan Kumar; Kaur, Rajwinder; Tyagi, Rajeshwar D

2017-01-01

In situ transesterification of oleaginous yeast wet biomass for fatty acid methyl esters (FAMEs) production using acid catalyst, methanol with or without N-Lauroyl sarcosine (N-LS) treatment was performed. The maximum FAMEs yield obtained with or without N-LS treatment in 24h reaction time was 96.1±1.9 and 71±1.4% w/w, respectively. The N-LS treatment of biomass followed by with or without ultrasonication revealed maximum FAMEs yield of 94.3±1.9% and 82.9±1.8% w/w using methanol to lipid molar ratio 360:1 and catalyst concentration 360mM (64μL H 2 SO 4 /g lipid) within 5 and 25min reaction time, respectively. The FAMEs composition obtained in in situ transesterification was similar to that obtained with conventional two step lipid extraction and transesterification process. Biodiesel fuel properties (density, kinematic viscosity, cetane number and total glycerol) were in accordance with international standard (ASTM D6751), which suggests the suitability of biodiesel as a fuel. Copyright © 2016 Elsevier Ltd. All rights reserved.

The yeast stands alone: the future of protein biologic production.

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Love, Kerry R; Dalvie, Neil C; Love, J Christopher

2017-12-22

Yeasts are promising alternative hosts for the manufacturing of recombinant protein therapeutics because they simply and efficiently meet needs for both platform and small-market drugs. Fast accumulation of biomass and low-cost media reduce the cost-of-goods when using yeast, which in turn can enable agile, small-volume manufacturing facilities. Small, tractable yeast genomes are amenable to rapid process development, facilitating strain and product quality by design. Specifically, Pichia pastoris is becoming a widely accepted yeast for biopharmaceutical manufacturing in much of the world owing to a clean secreted product and the rapidly expanding understanding of its cell biology as a host organism. We advocate for a near term partnership spanning industry and academia to promote open source, timely development of yeast hosts. Copyright © 2017. Published by Elsevier Ltd.

Optimization of biomass and dihydroorotase (DHOase) production ...

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Growth conditions which maintains DHOase overproduction by Saccharomyces cerevisiae MNJ3 (pMNJ1) and allow sufficient biomass production to ensure DHoase's purification were investigated. We used as basal medium the Yeast Carbon Base (YCB; Difco), especially designed for studies of nitrogen metabolism in ...

Non-canonical regulation of glutathione and trehalose biosynthesis characterizes non-Saccharomyces wine yeasts with poor performance in active dry yeast production

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Esther Gamero-Sandemetrio

2018-01-01

Full Text Available Several yeast species, belonging to Saccharomyces and non-Saccharomyces genera, play fundamental roles during spontaneous must grape fermentation, and recent studies have shown that mixed fermentations, co-inoculated with S. cerevisiae and non-Saccharomyces strains, can improve wine organoleptic properties. During active dry yeast (ADY production, antioxidant systems play an essential role in yeast survival and vitality as both biomass propagation and dehydration cause cellular oxidative stress and negatively affect technological performance. Mechanisms for adaptation and resistance to desiccation have been described for S. cerevisiae, but no data are available on the physiology and oxidative stress response of non-Saccharomyces wine yeasts and their potential impact on ADY production. In this study we analyzed the oxidative stress response in several non-Saccharomyces yeast species by measuring the activity of reactive oxygen species (ROS scavenging enzymes, e.g., catalase and glutathione reductase, accumulation of protective metabolites, e.g., trehalose and reduced glutathione (GSH, and lipid and protein oxidation levels. Our data suggest that non-canonical regulation of glutathione and trehalose biosynthesis could cause poor fermentative performance after ADY production, as it corroborates the corrective effect of antioxidant treatments, during biomass propagation, with both pure chemicals and food-grade argan oil.

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

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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.

Use of sugar cane molasses and vinasse for proteic and lipidic biomass production by yeast and bacteria

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Marcia Luciana Cazetta

2005-02-01

Full Text Available This work evaluated the lipid and protein growth and synthesis capacity by Saccharomyces cerevisiae, Rhodotoruda mucilaginosa, Candida lipolytica, a yeast isolated from vinasse lakes and Corynebacterium glutamicum in 10% molasses and sugar cane crude vinasse. All microorganisms grew both in molasses and vinasse. The highest growth in crude vinasse was performed by R. mucilaginosa (7.05 g/L, and in 10% molasses, by C. lipolytica, yielding 6,09 g/L. In vinasse, the highest protein content in the biomass was produced by S. cerevisiae (50.35% and in 10% molasses, by C. glutamicum (46,16%. C. lipolytica and R. mucilaginosa showed the best lipid production, above 20% and 18%, respectively, both in vinasse and in molasses.

Nutritional Requirements for the Mycelial Biomass and Exopolymer Production by Hericium erinaceus CZ-2

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Daming Huang

2007-01-01

Full Text Available In this work, the effects of medium composition and fermentation parameters on the simultaneous production of mycelial biomass and exopolymer by medicinal mushroom Hericium erinaceus CZ-2 were investigated in shake flask cultures using one-factor-at-a-time method and orthogonal array design. Results showed that the most suitable carbon, nitrogen, mineral sources, and cofactors for the mycelial biomass and exopolymer production were: corn flour combined with 1 % glucose, yeast extract, KH2PO4 and corn steep liquor. The intuitive analysis of orthogonal array design results indicated that the effects of nutritional requirement on the mycelial growth of Hericium erinaceus CZ-2 were in regular sequence of corn flour combined with 1 % glucose > yeast extract > corn steep liquor > KH2PO4, and those on exopolymer production were in the order of corn flour combined with glucose > KH2PO4 > yeast extract > corn steep liquor. The maximal yield of mycelial biomass (16.07 g/L was obtained when the composition of the culture medium was (in g/L: corn flour 30, glucose 10, yeast extract 3, KH2PO4 1, CaCO3 0.5, and 15 mL/L of corn steep liquor; while the maximal exopolymer yield (1.314 g/L was achieved when the composition of medium was (in g/L: corn flour 30, glucose 10, yeast extract 5, KH2PO4 3, CaCO3 0.5, and 15 mL/L of corn steep liquor. In the 15-litre scale-up fermentation, the maximum mycelial biomass yield of 20.50 g/L was achieved using the optimized medium.

Evaluation of Yeast Biomass (Candida utilis in a Practical Diet for Rainbow Trout (Oncorhynchus mykiss

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J.S. Goddard

1999-01-01

Full Text Available A yeast, Candida utilis, cultured on a substrate derived from a mixture of peat moss and fish processing waste, was substituted for fish meal in a practical diet for rainbow trout, Oncorhynchus mykiss. The formulated diets were isonitrogenous (40% crude protein and isoealoric (gross energy 20 kJ per g dry matter. During a 50-day feeding trial fish tripled in weight, and there were no significant differences in the mean final weights of groups of fish fed diets in which 0%, 25% and 35% of fishmeal had been replaced by yeast biomass. Diets containing yeast were palatable, as determined by food intake, and were highly digestible for protein. Carcass analysis revealed that the fish fed with yeast biomass had slightly higher crude protein and ash contents, and lower lipid levels than those of the control group. Significant reductions were recorded in food conversion efficiency as the yeast content of the diets increased. The results indicate the potential for partial replacement of fish meal (between 25-35% by Candida utilis biomass in feeds formulated for rainbow trout.

Influence of the Addition of Riboflavin in Culture Medium on Delivering Biomass Using Yeast Strains of Saccharomyces Carlsbengensis

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Cornelia Nicoară

2010-05-01

Full Text Available Yeasts requirements for growth factors should be considered both in terms of ability to summarize the simpleaverage and the dependence on external supplies. Vitamins are components of coenzymes or enzymes prostheticgroups and thus they are growth factors for yeast. The study concerns about the influence of the addition ofriboflavin in culture medium in different quantities, the accumulation of yeast biomass under the action of yeaststrains of beer. The process of cultivation has been made for 24 hours at a temperature of 220C. The addition ofriboflavin in culture medium of yeast biomass increased in each strain of yeast compared with the witness - thesample without added riboflavin. Biomass obtained by follow this procedure could be used to create new foodproducts with high ration nutritional value.

Evaluation of specific lipid production and nutrients removal from wastewater by Rhodosporidium toruloides and biodiesel production from wet biomass via microwave irradiation

International Nuclear Information System (INIS)

Ling, Jiayin; Nip, Saiwa; Alves de Toledo, Renata; Tian, Yuan; Shim, Hojae

2016-01-01

This study investigated the potential use of yeast Rhodosporidium toruloides for lipid production and removal of organics and nutrients while treating a mixture of distillery and domestic wastewater at low cost without sterilization. The highest specific biomass (24.1 × 10"−"9 g L"−"1 cell"−"1 h"−"1), lipid yield (9.9 × 10"−"9 g L"−"1 cell"−"1 h"−"1), and lipid content (8.54 × 10"−"3 g lipid g"−"1 biomass h"−"1) were achieved on the 2nd day of cultivation. The organics and nutrients removal also reached the highest removal rates within 2 days, with the specific removal rates for COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) at 39.5, 2.57, and 0.29 × 10"−"9 mg cell"−"1 h"−"1, respectively. The indigenous microorganisms slightly contributed to both lipid production and removal of organics and nutrients. The direct transesterification process via microwave irradiation from wet biomass was further optimized under the conditions of solvent to wet biomass rate 16 mL/g, methanol and chloroform mix rate 1:1, addition of catalyst H_2SO_4 6%, and reaction time 10 min at the reaction temperature of 60 °C. The FAMEs (fatty acid methyl esters) composition and the possibility of biodiesel production from wet oleaginous yeast biomass by the direct transesterification were also assessed. - Highlights: • Yeast Rhodosporidium toruloides used for lipid production in real mixed wastewater. • No significant lipid production and nutrients removal by indigenous organisms. • Highest specific lipid production and nutrient removal rates achieved with 0.05 × 10"8 cells mL"−"1. • Biodiesel production from wet biomass via microwave assisted direct transesterification is feasible.

Reduction of oxidative cellular damage by overexpression of the thioredoxin TRX2 gene improves yield and quality of wine yeast dry active biomass

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Ros Joaquim

2010-02-01

Full Text Available Abstract Background Wine Saccharomyces cerevisiae strains, adapted to anaerobic must fermentations, suffer oxidative stress when they are grown under aerobic conditions for biomass propagation in the industrial process of active dry yeast production. Oxidative metabolism of sugars favors high biomass yields but also causes increased oxidation damage of cell components. The overexpression of the TRX2 gene, coding for a thioredoxin, enhances oxidative stress resistance in a wine yeast strain model. The thioredoxin and also the glutathione/glutaredoxin system constitute the most important defense against oxidation. Trx2p is also involved in the regulation of Yap1p-driven transcriptional response against some reactive oxygen species. Results Laboratory scale simulations of the industrial active dry biomass production process demonstrate that TRX2 overexpression increases the wine yeast final biomass yield and also its fermentative capacity both after the batch and fed-batch phases. Microvinifications carried out with the modified strain show a fast start phenotype derived from its enhanced fermentative capacity and also increased content of beneficial aroma compounds. The modified strain displays an increased transcriptional response of Yap1p regulated genes and other oxidative stress related genes. Activities of antioxidant enzymes like Sod1p, Sod2p and catalase are also enhanced. Consequently, diminished oxidation of lipids and proteins is observed in the modified strain, which can explain the improved performance of the thioredoxin overexpressing strain. Conclusions We report several beneficial effects of overexpressing the thioredoxin gene TRX2 in a wine yeast strain. We show that this strain presents an enhanced redox defense. Increased yield of biomass production process in TRX2 overexpressing strain can be of special interest for several industrial applications.

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.

Thermodynamic analysis of fermentation and anaerobic growth of baker's yeast for ethanol production.

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Teh, Kwee-Yan; Lutz, Andrew E

2010-05-17

Thermodynamic concepts have been used in the past to predict microbial growth yield. This may be the key consideration in many industrial biotechnology applications. It is not the case, however, in the context of ethanol fuel production. In this paper, we examine the thermodynamics of fermentation and concomitant growth of baker's yeast in continuous culture experiments under anaerobic, glucose-limited conditions, with emphasis on the yield and efficiency of bio-ethanol production. We find that anaerobic metabolism of yeast is very efficient; the process retains more than 90% of the maximum work that could be extracted from the growth medium supplied to the chemostat reactor. Yeast cells and other metabolic by-products are also formed, which reduces the glucose-to-ethanol conversion efficiency to less than 75%. Varying the specific ATP consumption rate, which is the fundamental parameter in this paper for modeling the energy demands of cell growth, shows the usual trade-off between ethanol production and biomass yield. The minimum ATP consumption rate required for synthesizing cell materials leads to biomass yield and Gibbs energy dissipation limits that are much more severe than those imposed by mass balance and thermodynamic equilibrium constraints. 2010 Elsevier B.V. All rights reserved.

The production of arabitol by a novel plant yeast isolate Candida parapsilosis 27RL-4

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Kordowska-Wiater Monika

2017-10-01

Full Text Available Polyalcohol arabitol can be used in the food and pharmaceutical industries as a natural sweetener, a dental caries reducer, and texturing agent. Environmental samples were screened to isolate effective yeast producers of arabitol. The most promising isolate 27RL-4, obtained from raspberry leaves, was identified genetically and biochemically as Candida parapsilosis. It secreted 10.42– 10.72 g l-1 of product from 20 g l-1 of L-arabinose with a yield of 0.51 - 0.53 g g-1 at 28°C and a rotational speed of 150 rpm. Batch cultures showed that optimal pH value for arabitol production was 5.5. High yields and productivities of arabitol were obtained during incubation of the yeast at 200 rpm, or at 32°C, but the concentrations of the polyol did not exceed 10 g l-1. In modified medium, with reduced amounts of nitrogen compounds and pH 5.5-6.5, lower yeast biomass produced a similar concentration of arabitol, suggesting higher efficiency of yeast cells. This strain also produced arabitol from glucose, with much lower yields. The search for new strains able to successfully produce arabitol is important for allowing the utilization of sugars abundant in plant biomass.

Engineered Trx2p industrial yeast strain protects glycolysis and fermentation proteins from oxidative carbonylation during biomass propagation

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Gómez-Pastor Rocío

2012-01-01

Full Text Available Abstract Background In the yeast biomass production process, protein carbonylation has severe adverse effects since it diminishes biomass yield and profitability of industrial production plants. However, this significant detriment of yeast performance can be alleviated by increasing thioredoxins levels. Thioredoxins are important antioxidant defenses implicated in many functions in cells, and their primordial functions include scavenging of reactive oxygen species that produce dramatic and irreversible alterations such as protein carbonylation. Results In this work we have found several proteins specifically protected by yeast Thioredoxin 2 (Trx2p. Bidimensional electrophoresis and carbonylated protein identification from TRX-deficient and TRX-overexpressing cells revealed that glycolysis and fermentation-related proteins are specific targets of Trx2p protection. Indeed, the TRX2 overexpressing strain presented increased activity of the central carbon metabolism enzymes. Interestingly, Trx2p specifically preserved alcohol dehydrogenase I (Adh1p from carbonylation, decreased oligomer aggregates and increased its enzymatic activity. Conclusions The identified proteins suggest that the fermentative capacity detriment observed under industrial conditions in T73 wine commercial strain results from the oxidative carbonylation of specific glycolytic and fermentation enzymes. Indeed, increased thioredoxin levels enhance the performance of key fermentation enzymes such as Adh1p, which consequently increases fermentative capacity.

Towards the design of an optimal strategy for the production of ergosterol from Saccharomyces cerevisiae yeasts.

Science.gov (United States)

Náhlík, Jan; Hrnčiřík, Pavel; Mareš, Jan; Rychtera, Mojmír; Kent, Christopher A

2017-05-01

The total yield of ergosterol produced by the fermentation of the yeast Saccharomyces cerevisiae depends on the final amount of yeast biomass and the ergosterol content in the cells. At the same time ergosterol purity-defined as percentage of ergosterol in the total sterols in the yeast-is equally important for efficient downstream processing. This study investigated the development of both the ergosterol content and ergosterol purity in different physiological (metabolic) states of the microorganism S. cerevisiae with the aim of reaching maximal ergosterol productivity. To expose the yeast culture to different physiological states during fermentation an on-line inference of the current physiological state of the culture was used. The results achieved made it possible to design a new production strategy, which consists of two preferable metabolic states, oxidative-fermentative growth on glucose followed by oxidative growth on glucose and ethanol simultaneously. Experimental application of this strategy achieved a value of the total efficiency of ergosterol production (defined as product of ergosterol yield coefficient and volumetric productivity), 103.84 × 10 -6 g L -1 h -1 , more than three times higher than with standard baker's yeast fed-batch cultivations, which attained in average 32.14 × 10 -6 g L -1 h -1 . At the same time the final content of ergosterol in dry biomass was 2.43%, with a purity 86%. These results make the product obtained by the proposed control strategy suitable for effective down-stream processing. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:838-848, 2017. © 2017 American Institute of Chemical Engineers.

Use of Several waste substrates for carotenoid-rich yeast biomass production

International Nuclear Information System (INIS)

Marova, I.; Carnecka, M.; Halienova, A.; Dvorakova, T.; Haronikova, A.

2009-01-01

Carotenoids are industrially significant pigments produced in many bacteria, fungi, and plants. Carotenoid biosynthesis in yeasts is involved in stress response mechanisms. Thus, control ed physiological and nutrition stress can be used for enhanced pigment production. Huge commercial demand for natural carotenoids has focused attention on developing of suitable biotechnological techniques including use of liquid waste substrates as carbon and/or nitrogen source. (Author)

Thermotolerant Yeasts for Bioethanol Production Using Lignocellulosic Substrates

Science.gov (United States)

Pasha, Chand; Rao, L. Venkateswar

No other sustainable option for production of transportation fuels can match ethanol made from lignocellulosic biomass with respect to its dramatic environmental, economic, strategic and infrastructure advantages. Substantial progress has been made in advancing biomass ethanol (bioethanol) production technology to the point that it now has commercial potential, and several firms are engaged in the demanding task of introducing first-of-a-kind technology into the marketplace to make bioethanol a reality in existing fuel-blending markets. In order to lower pollution India has a long-term goal to use biofuels (bioethanol and biodiesel). Ethanol may be used either in pure form, or as a blend in petrol in different proportions. Since the cost of raw materials, which can account up to 50 % of the total production cost, is one of the most significant factors affecting the economy of alcohol, nowadays efforts are more concentrated on using cheap and abundant raw materials. Several forms of biomass resources exist (starch or sugar crops, weeds, oil plants, agricultural, forestry and municipal wastes) but of all biomass cellulosic resources represent the most abundant global source. The lignocellulosic materials include agricultural residues, municipal solid wastes (MSW), pulp mill refuse, switchgrass and lawn, garden wastes. Lignocellulosic materials contain two types of polysaccharides, cellulose and hemicellulose, bound together by a third component lignin. The principal elements of the lignocellulosic research include: i) evaluation and characterization of the waste feedstock; ii) pretreatment including initial clean up or dewatering of the feedstock; and iii) development of effective direct conversion bioprocessing to generate ethanol as an end product. Pre-treatment of lignocellulosic materials is a step in which some of the hemicellulose dissolves in water, either as monomeric sugars or as oligomers and polymers. The cellulose cannot be enzymatically hydrolyzed to

Utilization of hydrothermally pretreated wheat straw for production of bioethanol and carotene-enriched biomass

DEFF Research Database (Denmark)

Petrik, SiniŠa; Márová, Ivana; Kádár, Zsófia

2013-01-01

In this work hydrothermally pretreated wheat straw was used for production of bioethanol by Saccharomyces cerevisiae and carotene-enriched biomass by red yeasts Rhodotorula glutinis, Cystofilobasidium capitatum and Sporobolomyces roseus. To evaluate the convertibility of pretreated wheat straw...

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.

Metabolic Engineering of Oleaginous Yeasts for Fatty Alcohol Production

Energy Technology Data Exchange (ETDEWEB)

Wang, Wei; Wei, Hui; Knoshaug, Eric; Van Wychen, Stefanie; Xu, Qi; Himmel, Michael E.; Zhang, Min

2016-04-25

To develop pathways for advanced biological upgrading of sugars to hydrocarbons, we are seeking biological approaches to produce high carbon efficiency intermediates amenable to separations and catalytic upgrading to hydrocarbon fuels. In this study, we successfully demonstrated fatty alcohol production by oleaginous yeasts Yarrowia lipolytica and Lipomyces starkeyi by expressing a bacteria-derived fatty acyl-CoA reductase (FAR). Moreover, we find higher extracellular distribution of fatty alcohols produced by FAR-expressing L. starkeyi strain as compared to Y. lipolytica strain, which would benefit the downstream product recovery process. In both oleaginous yeasts, long chain length saturated fatty alcohols were predominant, accounting for more than 85% of the total fatty alcohols produced. To the best of our knowledge, this is the first report of fatty alcohol production in L. starkeyi. Taken together, our work demonstrates that in addition to Y. lipolytica, L. starkeyi can also serve as a platform organism for production of fatty acid-derived biofuels and bioproducts via metabolic engineering. We believe strain and process development both will significantly contribute to our goal of producing scalable and cost-effective fatty alcohols from renewable biomass.

Synergistic effects of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris for enhancement of biomass and lipid yields.

Science.gov (United States)

Zhang, Zhiping; Ji, Hairui; Gong, Guiping; Zhang, Xu; Tan, Tianwei

2014-07-01

The optimal mixed culture model of oleaginous yeast Rhodotorula glutinis and microalga Chlorella vulgaris was confirmed to enhance lipid production. A double system bubble column photo-bioreactor was designed and used for demonstrating the relationship of yeast and alga in mixed culture. The results showed that using the log-phase cultures of yeast and alga as seeds for mixed culture, the improvements of biomass and lipid yields reached 17.3% and 70.9%, respectively, compared with those of monocultures. Growth curves of two species were confirmed in the double system bubble column photo-bioreactor, and the second growth of yeast was observed during 36-48 h of mixed culture. Synergistic effects of two species for cell growth and lipid accumulation were demonstrated on O2/CO2 balance, substance exchange, dissolved oxygen and pH adjustment in mixed culture. This study provided a theoretical basis and culture model for producing lipids by mixed culture in place of monoculture. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production of Food Grade Yeasts

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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.

Biogas Production from Brewer’s Yeast Using an Anaerobic Sequencing Batch Reactor

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Gregor Drago Zupančič

2017-01-01

Full Text Available Renewable energy sources are becoming increasingly important in the beverage and food industries. In the brewing industry, a significant percentage of the used raw materials finishes the process as secondary resource or waste. The research on the anaerobic digestion of brewer’s yeast has been scarce until recent years. One of the reasons for this is its use as a secondary resource in the food industry and as cattle feed. Additionally, market value of brewer’s yeast is higher than its energy value. Due to the increase of energy prices, brewer’s yeast has become of interest as energy substrate despite its difficult degradability in anaerobic conditions. The anaerobic co-digestion of brewer’s yeast and anaerobically treated brewery wastewater was studied using a pilot-scale anaerobic sequencing batch reactor (ASBR seeded with granular biomass. The experiments showed very good and stable operation with an organic loading rate of up to 8.0 kg/(m3·day, and with a maximum achieved organic loading rate of 13.6 kg/(m3·day in a single cycle. A specific biogas productivity of over 0.430 m3/kg of the total chemical oxygen demand (COD inserted, and total COD removal efficiencies of over 90 % were achieved. This study suggests that the brewer’s yeast can be successfully digested in an ASBR without adverse effects on the biogas production from brewer’s yeast/wastewater mixtures of up to 8 % (by volume. By using the brewer’s yeast in the ASBR process, the biogas production from brewery wastewater could be increased by 50 %.

Effect of yeast biomass with high content of carotenoids on erythrocyte deformability, NO production and Na,K-ATPase activity in healthy and LPS treated rats.

Science.gov (United States)

Radosinska, J; Mezesova, L; Okruhlicova, L; Frimmel, K; Breierova, E; Bartekova, M; Vrbjar, N

2016-11-25

Measurements of red blood cell (RBC) deformability together with estimation of NO-synthase activity and Na,K-ATPase activity were used for characterization of RBC functionality in rats subjected to single dose of Escherichia coli lipopolysaccharides (LPS) at a dose of 1 mg/kg. We hypothesized that LPS might initiate a malfunction of RBC. We also investigated the potential effect of carotenoids (10 mg/kg/day) produced in red yeast biomass of Rhodotorula glutinis on RBC in LPS-challenged rats. LPS significantly reduced the deformability of RBC (by 14%) together with decrease of NO-synthase activity by 20%. Daily supplementation of carotenoids for 10 days attenuated the LPS-induced injury, as observed by 22% increase of RBC deformability and 23% increase of NO-synthase activity. The activity of Na,K-ATPase was also improved probably due to increased number of active enzyme molecules as indicated by 66% enhancement of Vmax value, hence maintaining the activity of erythrocyte Na,K-ATPase to the level even higher as compared with healthy control animals. It may be concluded that administration of yeast biomass with high content of carotenoids resulted in advanced function of erythrocytes as concerns their ability to squeeze through narrow capillaries of the circulation, better intrinsic production of NO and improvement of intracellular homeostasis of sodium.

EVALUACIÓN DEL CONTENIDO DE NUTRIENTES Y PRODUCCIÓN DE BIOMASA EN CEPAS DE LEVADURA COLOMBIANAS Y COMERCIALES EVALUATION OF THE NUTRIENT CONTENT AND BIOMASS PRODUCTION IN COLOMBIAN AND COMMERCIAL YEAST STRAINS

Directory of Open Access Journals (Sweden)

Nohora Patricia Manovacía Moreno

2008-12-01

Full Text Available En el presente estudio se evaluó la producción de biomasa, el contenido de algunos nutrientes (selenio, carbohidratos totales y proteína microbiana y el consumo de sustrato de cepas de levaduras comerciales y nativas pertenecientes al Banco de Germoplasma de la Nación Colombiana, manejado por la Corporación Colombiana de Investigación Agropecuaria, CORPOICA. Inicialmente se determinó el crecimiento de tres levaduras nativas seleccionadas al azar bajo diferentes condiciones de pH, temperatura y tiempo de fermentación usando un medio líquido de extracto de malta. Dentro de estas condiciones, las mejores respuestas se observaron a pH de 4,5, 25 °C y 24 horas de fermentación. Usando estas condiciones se evaluaron 100 accesiones de levaduras nativas y 4 comerciales por su producción de biomasa, contenido de selenio, carbohidratos totales y proteína microbiana y consumo de sustratos. De acuerdo con estas variables y un análisis de conglomerados fue posible agrupar las levaduras en grupos homogéneos. Hubo elevada variabilidad en la producción de biomasa entre las 104 cepas evaluadas, probablemente debido a la variabilidad biológica existente en la población estudiada. Los rendimientos de biomasa variaron entre 0,101 y 0,480 g de biomasa g-1 de azúcar consumido y las velocidades de producción de biomasa oscilaron entre 0,040 y 0,185 g L-1 h-1. El consumo promedio de nutrientes (g de nutrientes consumidos/ g de nutrientes disponibles fue de 91,6% en el caso de los carbohidratos y de 17,8% en el caso de la proteína. Se identificaron diez cepas de superior crecimiento y contenido de nutrientes, cuyo potencial prebiótico y probiótico será evaluado en futuros ensayos In vivo.In the present study biomass production and nutrient (selenium, total carbohydrate and microbial protein were evaluated in both commercial and native yeast isolates from the Colombian Germplasm Bank managed by the Colombian Corporation of Agricultural Research

Effect of the yeast and bacteria biomass on the microbiota in the rumen.

Science.gov (United States)

Vamanu, E; Vamanu, A; Popa, O; Vassu, Tatiana; Ghindea, Raluca; Pelinescu, Diana; Nita, Sultana; Babeanu, Narcisa

2008-09-15

This study aims at obtaining a probiotic product based on viable biomass from 6 yeast strains and 2 strains of lactic bacteria used for nutrition of animals. The strains are subjected to some resistance tests, at temperature, pH, pepsin, pancreatin and biliary salts so as to make obvious their viability. Tests were done by comparison to the witness strain and respectively a protective solution based on mucin and casein. Based on the resulted viabilities 2 products are formulated. Their effect is tested by inoculating fresh rumen content and supervising the microbic balance for a period of 12 days. After the final tests, it resulted that the product Fpl (20% Saccharomyces cerevisiae 1-29, 10% Kluyveromyces marxianus R-CS, 20% Issatchenkia orientalis R-BC, 30% Lactobacillus paracasei CMGB16, 20% Enterococcus faecium GM8) was chosen because anaerobic strains were preponderant as a consequence of the tests performed with rumen.

Biomass production and biological depuration of sugar cane vinasse by mixed culture of filamentous fungi and yeasts; Producao de biomassa e depuracao biologica da vinhaca de cana-de-acucar por cultura mista de fungos filamentosos e leveduras

Energy Technology Data Exchange (ETDEWEB)

Ceccato, Sandra Regina

1988-12-01

Sugar and alcohol technology has originated wastes such as vinasse with organic load that causes pollution in Brazil. Many alternatives have been proposed to convert it into useful products such as microbial protein. The aim of this work was to select mixed cultures of filamentous fungi and yeasts with high biomass production in vinasse and to study the cultural condition optimization of the selected combination based on the protein content and the waste depuration. The growth of pure cultures along the time was also evaluated as well as the amino acid composition of the biomass obtained. (author)

Intracellular biosynthesis and removal of copper nanoparticles by dead biomass of yeast isolated from the wastewater of a mine in the Brazilian Amazonia.

Directory of Open Access Journals (Sweden)

Marcia R Salvadori

Full Text Available In this study was developed a natural process using a biological system for the biosynthesis of nanoparticles (NPs and possible removal of copper from wastewater by dead biomass of the yeast Rhodotorula mucilaginosa. Dead and live biomass of Rhodotorula mucilaginosa was used to analyze the equilibrium and kinetics of copper biosorption by the yeast in function of the initial metal concentration, contact time, pH, temperature, agitation and inoculum volume. Dead biomass exhibited the highest biosorption capacity of copper, 26.2 mg g(-1, which was achieved within 60 min of contact, at pH 5.0, temperature of 30°C, and agitation speed of 150 rpm. The equilibrium data were best described by the Langmuir isotherm and Kinetic analysis indicated a pseudo-second-order model. The average size, morphology and location of NPs biosynthesized by the yeast were determined by scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS and transmission electron microscopy (TEM. The shape of the intracellularly synthesized NPs was mainly spherical, with an average size of 10.5 nm. The X-ray photoelectron spectroscopy (XPS analysis of the copper NPs confirmed the formation of metallic copper. The dead biomass of Rhodotorula mucilaginosa may be considered an efficiently bioprocess, being fast and low-cost to production of copper nanoparticles and also a probably nano-adsorbent of this metal ion in wastewater in bioremediation process.

STUDY CONCERNING THE PRODUCTION OF BIOMASS PROTEIN BY VALORISATION OF BY-PRODUCTS FROM THE DAIRY INDUSTRY ETUDE CONCERNANT L’OBTENTION DE BIOMASSE PROTEIQUE PAR VALORISATION DES SOUS-PRODUITS DE L’INDUSTRIE LAITIERE

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LUMINITA GROSU

2015-07-01

Full Text Available The development of the food industry ensures the necessary protein for the population and in this perspective the valorisation of by-products from the dairy industry (whey and buttermilk can be a solution in this direction. Whey is a very important substrate for the biosynthesis of single cell protein by its lactose content which is the main source of fermentable substrate for yeasts. As part of our research, the biomass protein was obtained using whey as source of lactose and other sugars and yeast strains of Candida utilis. The modelling program used is 2nd order system centred with three variables: amount of sugar, amount of nitrogen and quantity of phosphorus. The following parameters have been pursued: biomass content, yield of sugar consumption and protein content. The process conditions are influenced by the addition of different nutrients.

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.

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.

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.

Pectin-rich biomass as feedstock for fuel ethanol production.

Science.gov (United States)

Edwards, Meredith C; Doran-Peterson, Joy

2012-08-01

The USA has proposed that 30 % of liquid transportation fuel be produced from renewable resources by 2030 (Perlack and Stokes 2011). It will be impossible to reach this goal using corn kernel-based ethanol alone. Pectin-rich biomass, an under-utilized waste product of the sugar and juice industry, can augment US ethanol supplies by capitalizing on this already established feedstock. Currently, pectin-rich biomass is sold (at low value) as animal feed. This review focuses on the three most studied types of pectin-rich biomass: sugar beet pulp, citrus waste and apple pomace. Fermentations of these materials have been conducted with a variety of ethanologens, including yeasts and bacteria. Escherichia coli can ferment a wide range of sugars including galacturonic acid, the primary component of pectin. However, the mixed acid metabolism of E. coli can produce unwanted side products. Saccharomyces cerevisiae cannot naturally ferment galacturonic acid nor pentose sugars but has a homoethanol pathway. Erwinia chrysanthemi is capable of degrading many of the cell wall components of pectin-rich materials, including pectin. Klebsiella oxytoca can metabolize a diverse array of sugars including cellobiose, one degradation product of cellulose. However, both E. chrysanthemi and K. oxytoca produce side products during fermentation, similar to E. coli. Using pectin-rich residues from industrial processes is beneficial because the material is already collected and partially pretreated to facilitate enzymatic deconstruction of the plant cell walls. Using biomass already produced for other purposes is an attractive practice because fewer greenhouse gases (GHG) will be anticipated from land-use changes.

Pectin-rich biomass as feedstock for fuel ethanol production

Energy Technology Data Exchange (ETDEWEB)

Edwards, Meredith C.; Doran-Peterson, Joy [Georgia Univ., Athens, GA (United States). Dept. of Microbiology

2012-08-15

The USA has proposed that 30 % of liquid transportation fuel be produced from renewable resources by 2030 (Perlack and Stokes 2011). It will be impossible to reach this goal using corn kernel-based ethanol alone. Pectin-rich biomass, an under-utilized waste product of the sugar and juice industry, can augment US ethanol supplies by capitalizing on this already established feedstock. Currently, pectin-rich biomass is sold (at low value) as animal feed. This review focuses on the three most studied types of pectin-rich biomass: sugar beet pulp, citrus waste and apple pomace. Fermentations of these materials have been conducted with a variety of ethanologens, including yeasts and bacteria. Escherichia coli can ferment a wide range of sugars including galacturonic acid, the primary component of pectin. However, the mixed acid metabolism of E. coli can produce unwanted side products. Saccharomyces cerevisiae cannot naturally ferment galacturonic acid nor pentose sugars but has a homoethanol pathway. Erwinia chrysanthemi is capable of degrading many of the cell wall components of pectin-rich materials, including pectin. Klebsiella oxytoca can metabolize a diverse array of sugars including cellobiose, one degradation product of cellulose. However, both E. chrysanthemi and K. oxytoca produce side products during fermentation, similar to E. coli. Using pectin-rich residues from industrial processes is beneficial because the material is already collected and partially pretreated to facilitate enzymatic deconstruction of the plant cell walls. Using biomass already produced for other purposes is an attractive practice because fewer greenhouse gases (GHG) will be anticipated from land-use changes. (orig.)

Revaluation of Waste Yeast from Beer Production

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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.

Effect of inoculum and molasses concentration as supplement to vinasse of distillery for the production of biomass of native Candida utilis

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Lady Cajo

2011-06-01

Full Text Available Vinasse is a residue of alcohol distilleries, rich in mineral salts and organic matter, whose use is limited and finally it is poured to the sewage system, causing pollution, nevertheless, can constitute a substrate for the production of biomass yeasts, used in the animal feed. In the present investigation was determined the effect of the concentration of the inoculum and the molasses as supplement of the vinasse, for the production of biomass of native Candida utilis. Yeasts were isolated of leaves of Zea mays L. "maize" in Sabouraud glucosade agar, were identified 40.23 % as C. utilis. Next, were cultivated in vinasse with 30 g/L of molasses, to 28 ºC, during 24 hours, the biomass was weighed and was selected C. utilis MKJ12, because it had the highest biomass value of 7.667 g/L. This yeast in concentration of 25, 50 and 75 mL/L of inoculum was cultivated in bioreactors Batch tank type containing 300 mL of vinasse with 10, 30, and 50 g/L of molasses, with downward air flow (1vvm, and incubation was 28 ºC during 20 hours. With 50 mL/L of inoculum and 50 g/L of molasses was determined the shortest generation time (2.88 h and the highest values in number of generations (6.95, specific rate of growth (0.35 h-1 , weight of biomass (11.78 g/L and percentage of protein (40.15 %. Feasibility was demonstrated of the production of C. utilis biomass with 5 mL of inoculum in vinasse supplemented by molasses.

Improving conversion yield of fermentable sugars into fuel ethanol in 1st generation yeast-based production processes.

Science.gov (United States)

Gombert, Andreas K; van Maris, Antonius J A

2015-06-01

Current fuel ethanol production using yeasts and starch or sucrose-based feedstocks is referred to as 1st generation (1G) ethanol production. These processes are characterized by the high contribution of sugar prices to the final production costs, by high production volumes, and by low profit margins. In this context, small improvements in the ethanol yield on sugars have a large impact on process economy. Three types of strategies used to achieve this goal are discussed: engineering free-energy conservation, engineering redox-metabolism, and decreasing sugar losses in the process. Whereas the two former strategies lead to decreased biomass and/or glycerol formation, the latter requires increased process and/or yeast robustness. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

Science.gov (United States)

Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

2017-12-01

The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

Removal of copper ions from dilute solutions by Streptomyces noursei mycelium. Comparison with yeast biomass

Czech Academy of Sciences Publication Activity Database

Kujan, Petr; Prell, Aleš; Šafář, Hynek; Sobotka, Miroslav; Řezanka, Tomáš; Holler, Pavel

2005-01-01

Roč. 50, č. 4 (2005), s. 309-313 ISSN 0015-5632 Institutional research plan: CEZ:AV0Z50200510 Keywords : streptomyces noursei * copper * yeast biomass Subject RIV: EE - Microbiology, Virology Impact factor: 0.918, year: 2005

Energy production from biomass

International Nuclear Information System (INIS)

Bestebroer, S.I.

1995-01-01

The aim of the task group 'Energy Production from Biomass', initiated by the Dutch Ministry of Economic Affairs, was to identify bottlenecks in the development of biomass for energy production. The bottlenecks were identified by means of a process analysis of clean biomass fuels to the production of electricity and/or heat. The subjects in the process analysis are the potential availability of biomass, logistics, processing techniques, energy use, environmental effects, economic impact, and stimulation measures. Three categories of biomass are distinguished: organic residual matter, imported biomass, and energy crops, cultivated in the Netherlands. With regard to the processing techniques attention is paid to co-firing of clean biomass in existing electric power plants (co-firing in a coal-fired power plant or co-firing of fuel gas from biomass in a coal-fired or natural gas-fired power plant), and the combustion or gasification of clean biomass in special stand-alone installations. 5 figs., 13 tabs., 28 refs

Dextransucrase production using cashew apple juice as substrate: effect of phosphate and yeast extract addition.

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Chagas, Clarice M A; Honorato, Talita L; Pinto, Gustavo A S; Maia, Geraldo A; Rodrigues, Sueli

2007-05-01

Cashew apples are considered agriculture excess in the Brazilian Northeast because cashew trees are cultivated primarily with the aim of cashew nut production. In this work, the use of cashew apple juice as a substrate for Leuconostoc mesenteroides cultivation was investigated. The effect of yeast extract and phosphate addition was evaluated using factorial planning tools. Both phosphate and yeast extract addition were significant factors for biomass growth, but had no significant effect on maximum enzyme activity. The enzyme activities found in cashew apple juice assays were at least 3.5 times higher than the activity found in the synthetic medium. Assays with pH control (pH = 6.5) were also carried out. The pH-controlled fermentation enhanced biomass growth, but decreased the enzyme activity. Crude enzyme free of cells produced using cashew apple juice was stable for 16 h at 30 degrees C at a pH of 5.0.

Fermentation of biomass sugars to ethanol using native industrial yeast strains.

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Yuan, Dawei; Rao, Kripa; Relue, Patricia; Varanasi, Sasidhar

2011-02-01

In this paper, the feasibility of a technology for fermenting sugar mixtures representative of cellulosic biomass hydrolyzates with native industrial yeast strains is demonstrated. This paper explores the isomerization of xylose to xylulose using a bi-layered enzyme pellet system capable of sustaining a micro-environmental pH gradient. This ability allows for considerable flexibility in conducting the isomerization and fermentation steps. With this method, the isomerization and fermentation could be conducted sequentially, in fed-batch, or simultaneously to maximize utilization of both C5 and C6 sugars and ethanol yield. This system takes advantage of a pH-dependent complexation of xylulose with a supplemented additive to achieve up to 86% isomerization of xylose at fermentation conditions. Commercially-proven Saccharomyces cerevisiae strains from the corn-ethanol industry were used and shown to be very effective in implementation of the technology for ethanol production. Copyright © 2010 Elsevier Ltd. All rights reserved.

Application of Local Adsorbant From Southeast Sulawesi Clay Immobilized Saccharomyces Cerevisiae Bread’s Yeast Biomass for Adsorption Of Mn(Ii) Metal Ion

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R, Halimahtussaddiyah; Mashuni; Budiarni

2017-05-01

Southeast Sulawesi has a great stock of clay. It is probably to use as a source of adsorbent. The adsorbent capacity of clay can be largered with teratment using bread’s yeast as biomass. At this research, study of analysis adsorption of Mn(II) metal ion on clay immobilized Saccharomyces cerevisiae bread’s yeast biomass adsorbent has been conducted. The aims of this research were to determine the effects of contact time, pH and concentration of Mn(II) metal ion and to determine the adsorption capacity of clay immobilized S. cerevisiae biomass for adsorbtion of Mn(II) metal ion. Activated clay was synthesized by reaction of clay with KMnO4, H2SO4 and HCl. S. cerevisiae biomass was result by bread’s yeast mashed. Immobilization of S. cerevisiae biomass into clay was done by mixing of ratio of S. cerevisiae bread’s yeast biomass and clay equal to 1:3 (mass of biomassa : mass of clay). The adsorption capacity was determined by using Freundlich and Langmuir adsorption isoterms. The results of FTIR spectrums showed that the functional groups of clay immobilized S. cerevisiae biomass were Si-OH (wave number 1643 cm-1), Si-O-Si (wave number 1033 cm-1), N-H (wave number 2337 cm-1), O-H (wave number 3441cm-1), and C-H (wave number 2931 cm-1). The result of adsorption capacity from Mn(II) metal ion of contact time optimum 120 minutes, pH optimun at 7 and concentration optimum 50 mg/L were 1,816 mg/g; 0,509 mg/g and 2,624mg/g respectively. The adsorption capacity of Mn(II) metal ion with ratio 1:3 (biomass : clay) was 0,1045 mg/g. Type of isothermal adsorption followed the Freunlich adsorption.

Construction of a novel selection system for endoglucanases exhibiting carbohydrate-binding modules optimized for biomass using yeast cell-surface engineering.

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Nakanishi, Akihito; Bae, Jungu; Kuroda, Kouichi; Ueda, Mitsuyoshi

2012-10-23

To permit direct cellulose degradation and ethanol fermentation, Saccharomyces cerevisiae BY4741 (Δsed1) codisplaying 3 cellulases (Trichoderma reesei endoglucanase II [EG], T. reesei cellobiohydrolase II [CBH], and Aspergillus aculeatus β-glucosidase I [BG]) was constructed by yeast cell-surface engineering. The EG used in this study consists of a family 1 carbohydrate-binding module (CBM) and a catalytic module. A comparison with family 1 CBMs revealed conserved amino acid residues and flexible amino acid residues. The flexible amino acid residues were at positions 18, 23, 26, and 27, through which the degrading activity for various cellulose structures in each biomass may have been optimized. To select the optimal combination of CBMs of EGs, a yeast mixture with comprehensively mutated CBM was constructed. The mixture consisted of yeasts codisplaying EG with mutated CBMs, in which 4 flexible residues were comprehensively mutated, CBH, and BG. The yeast mixture was inoculated in selection medium with newspaper as the sole carbon source. The surviving yeast consisted of RTSH yeast (the mutant sequence of CBM: N18R, S23T, S26S, and T27H) and wild-type yeast (CBM was the original) in a ratio of 1:46. The mixture (1 RTSH yeast and 46 wild-type yeasts) had a fermentation activity that was 1.5-fold higher than that of wild-type yeast alone in the early phase of saccharification and fermentation, which indicates that the yeast mixture with comprehensively mutated CBM could be used to select the optimal combination of CBMs suitable for the cellulose of each biomass.

Conventional and Non-Conventional Yeasts in Beer Production

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Angela Capece

2018-06-01

Full Text Available The quality of beer relies on the activity of fermenting yeasts, not only for their good fermentation yield-efficiency, but also for their influence on beer aroma, since most of the aromatic compounds are intermediate metabolites and by-products of yeast metabolism. Beer production is a traditional process, in which Saccharomyces is the sole microbial component, and any deviation is considered a flaw. However, nowadays the brewing sector is faced with an increasing demand for innovative products, and it is diffusing the use of uncharacterized autochthonous starter cultures, spontaneous fermentation, or non-Saccharomyces starters, which leads to the production of distinctive and unusual products. Attempts to obtain products with more complex sensory characteristics have led one to prospect for non-conventional yeasts, i.e., non-Saccharomyces yeasts. These generally are characterized by low fermentation yields and are more sensitive to ethanol stress, but they provide a distinctive aroma and flavor. Furthermore, non-conventional yeasts can be used for the production of low-alcohol/non-alcoholic and light beers. This review aims to present the main findings about the role of traditional and non-conventional yeasts in brewing, demonstrating the wide choice of available yeasts, which represents a new biotechnological approach with which to target the characteristics of beer and to produce different or even totally new beer styles.

Pretreated densified biomass products

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Dale, Bruce E; Ritchie, Bryan; Marshall, Derek

2014-03-18

A product comprising at least one densified biomass particulate of a given mass having no added binder and comprised of a plurality of lignin-coated plant biomass fibers is provided, wherein the at least one densified biomass particulate has an intrinsic density substantially equivalent to a binder-containing densified biomass particulate of the same given mass and h a substantially smooth, non-flakey outer surface. Methods for using and making the product are also described.

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

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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.

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

BIOMASS PRODUCTION AND FORMULATION OF Bacillus subtilis FOR BIOLOGICAL CONTROL

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Amran Muis

2016-10-01

Full Text Available Bacillus subtilis is a widespread bacterium found in soil, water, and air. It controls the growth of certain harmful bacteria and fungi, presumably by competing for nutrients, growth sites on plants, and by directly colonizing and attaching to fungal pathogens. When applied to seeds, it colonizes the developing root system of the plants and continues to live on the root system and provides protection throughout the growing season. The study on biomass production and formulation of B. subtilis for biological control was conducted in the laboratory of Department of Plant Pathology, College of Agriculture, University of the Philippines Los Baños (UPLB-CA, College, Laguna from May to July 2005. The objective of the study was to determine the optimum pH and a good carbon source for biomass production of B. subtilis and to develop a seed treatment formulation of B. subtilis as biological control agent. Results showed that the optimum pH for growth of B. subtilis was pH 6 (1.85 x 109 cfu/ml. In laboratory tests for biomass production using cassava flour, corn flour, rice flour, and brown sugar as carbon sources, it grew best in brown sugar plus yeast extract medium (6.8 x 108 cfu ml-1 in sterile distilled water and 7.8 x 108 cfu ml-1 in coconut water. In test for bacterial biomass carriers, talc proved to be the best in terms of number of bacteria recovered from the seeds (3.98 x 105 cfu seed-1.

Effet du nombre de recyclages de la biomasse de Saccharomyces uvarum sur quelques paramètres de la fermentation primaire au cours de la production de la bière en Côte d'Ivoire

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Zebre, AC.

2011-01-01

Full Text Available Effect of the number of recycled biomass of the yeast Saccharomyces uvarum on some parameters of primary fermentation during beer production in Côte d'Ivoire. A study was conducted on the yeast Saccharomyces uvarum during the production of beer to determine the impact of the number of recycled yeast biomass on some primary fermentation parameters and to understand variations during primary fermentation time. The work was carried out with six cycles of beer production. The first cycle was done with the initial culture of S. uvarum and the five others with its recycled biomass. After each cycle of production, the yeast biomass obtained is re-used to inoculate another mash and the same operation was repeated until the sixth cycle of production of the beer. Thus during each of the six cycles, several parameters such as the rate of fermentation, the diacetyle reduction time, the rate of alcohol production, etc. were measured. The fifth and sixth cycles showed the longest primary fermentation time (10 days and the longest diacetyle reduction time (6.8 and 7.6 days respectively. The first and second cycles have the shortest primary fermentation time (8.33 and 8.25 days respectively and diacetyle reduction time (3.33 days for each cycle. The interval between the theoretical and the practical attenuation limit differs according to the cycle of production. The highest gap (0.51 was obtained with the last cycle (sixth while the shortest was obtained with the first cycle, 0.13. The fermentation rate varied from 1.71 to 1.97°P per day. The quantity of sugar consumed varied from 8.83 to 10.70°P and the rate of alcohol produced from 4.56 to 4.90°P. The yeast from the two last cycles flocculated quicker than the others. The number of cells in suspension for these cycles was 4.1.106 and 4.2.106 cells.ml-1 respectively versus 25.106 and 20.106 cells.ml-1 respectively for the two first cycles. The yeast biomass from the first four cycles should be used for the

Optimising culture medium for producing the yeast Pichia onychis (Lv027

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Andrés Díaz

2005-01-01

Full Text Available Optimising Pichia onychis yeast biomass production was evaluated using different substrates and different physicochemical conditions for liquid fermentation. The Plackett-Burman statistical design was initially applied for screening the most important nutritional variables (three carbon sources and eight nitrogen sources affecting yeast biomass production. Four nutritional sources and two physicochemical variables were subsequently evaluated using a factorial fractionated design as the starting point for optimising the process by applying a central composite rotational design. The results obtained f rom employing a polynomial regression model using the experimental data showed that biomass production was strongly affected by nutritional and physicochemical conditions. The highest yield was obtained in the following conditions: 43,42 g/L carbon source, 0,261 g/L nitrogen organic source, shaking at 110 rpm, 6,0 pH, 48 h total fermentation time during which 8,95 XlO9 cells/mL were obtained, equivalent to 6,30 g/L dry biomass. Key words: Pichia onychis, optimisation, liquid fermentation.

Production of astaxanthin rich feed supplement for animals from Phaffia rhodozyma yeast at low cost

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Irtiza, Ayesha; Shatunova, Svetlana; Glukhareva, Tatiana; Kovaleva, Elena

2017-09-01

Dietary nutrients such as amino acids, vitamins, minerals and antioxidants can play a significant role in determining meat quality and also the growth rate of poultry or animal. Phaffia rhodozyma was grown on waste from brewery industry to produce astaxanthin rich feed supplements at a very low cost. Phaffia rhodozyma is yeast specie that has ability to produce carotenoids and approximately 80% of its total carotenoid content is astaxanthin, which is highly valuable carotenoid for food, feed and aquaculture industry. This study was carried out to test yeast extract of spent yeast from brewing industry waste (residual yeast) as potential nitrogen source for growth of Phaffia rhodozyma. Cultivation was carried out in liquid media prepared by yeast extracts and other components (glucose and peptone). Carotenoids from the biomass were released into biomass by suspending cells in DMSO for destruction of cells followed by extraction with petroleum ether. The extracted carotenoids were studied by spectrophotometry to identify and quantify astaxanthin and other carotenoids produced.

Combined heat treatment and acid hydrolysis of cassava grate waste (CGW) biomass for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Agu, R.C.; Amadife, A.E.; Ude, C.M.; Onyia, A.; Ogu, E.O. [Enugu State Univ. of Science and Technology (Nigeria). Faculty of Applied Natural Sciences; Okafor, M.; Ezejiofor, E. [Nnamdi Azikiwe Univ., Awka (Nigeria). Dept. of Applied Microbiology

1997-12-31

The effect of combined heat treatment and acid hydrolysis (various concentrations) on cassava grate waste (CGW) biomass for ethanol production was investigated. At high concentrations of H{sub 2}SO{sub 4} (1--5 M), hydrolysis of the CGW biomass was achieved but with excessive charring or dehydration reaction. At lower acid concentrations, hydrolysis of CGW biomass was also achieved with 0.3--0.5 M H{sub 2}SO{sub 4}, while partial hydrolysis was obtained below 0.3 M H{sub 2}SO{sub 4} (the lowest acid concentration that hydrolyzed CGW biomass) at 120 C and 1 atm pressure for 30 min. A 60% process efficiency was achieved with 0.3 M H{sub 2}SO{sub 4} in hydrolyzing the cellulose and lignin materials present in the CGW biomass. High acid concentration is therefore not required for CGW biomass hydrolysis. The low acid concentration required for CGW biomass hydrolysis, as well as the minimal cost required for detoxification of CGW biomass because of low hydrogen cyanide content of CGW biomass would seem to make this process very economical. From three liters of the CGW biomass hydrolysate obtained from hydrolysis with 0.3M H{sub 2}SO{sub 4}, ethanol yield was 3.5 (v/v%) after yeast fermentation. However, although the process resulted in gainful utilization of CGW biomass, additional costs would be required to effectively dispose new by-products generated from CGW biomass processing.

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.

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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.

Xylose isomerase improves growth and ethanol production rates from biomass sugars for both Saccharomyces pastorianus and Saccharomyces cerevisiae.

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Miller, Kristen P; Gowtham, Yogender Kumar; Henson, J Michael; Harcum, Sarah W

2012-01-01

The demand for biofuel ethanol made from clean, renewable nonfood sources is growing. Cellulosic biomass, such as switch grass (Panicum virgatum L.), is an alternative feedstock for ethanol production; however, cellulosic feedstock hydrolysates contain high levels of xylose, which needs to be converted to ethanol to meet economic feasibility. In this study, the effects of xylose isomerase on cell growth and ethanol production from biomass sugars representative of switch grass were investigated using low cell density cultures. The lager yeast species Saccharomyces pastorianus was grown with immobilized xylose isomerase in the fermentation step to determine the impact of the glucose and xylose concentrations on the ethanol production rates. Ethanol production rates were improved due to xylose isomerase; however, the positive effect was not due solely to the conversion of xylose to xylulose. Xylose isomerase also has glucose isomerase activity, so to better understand the impact of the xylose isomerase on S. pastorianus, growth and ethanol production were examined in cultures provided fructose as the sole carbon. It was observed that growth and ethanol production rates were higher for the fructose cultures with xylose isomerase even in the absence of xylose. To determine whether the positive effects of xylose isomerase extended to other yeast species, a side-by-side comparison of S. pastorianus and Saccharomyces cerevisiae was conducted. These comparisons demonstrated that the xylose isomerase increased ethanol productivity for both the yeast species by increasing the glucose consumption rate. These results suggest that xylose isomerase can contribute to improved ethanol productivity, even without significant xylose conversion. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

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

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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.

Experimental study of the production of biomass by Sacharomyces ...

African Journals Online (AJOL)

SERVER

2008-04-17

Apr 17, 2008 ... h-1 exceeds by far the maximum specific growth rate of the yeast under aerobic condition as obtained ... use for bread-making, a staple food for large section of ..... mental yield of biomass may be inaccurate measurement.

Microbial lipid production by oleaginous yeast Cryptococcus sp. in the batch cultures using corncob hydrolysate as carbon source

International Nuclear Information System (INIS)

Chang, Yi-Huang; Chang, Ku-Shang; Lee, Ching-Fu; Hsu, Chuan-Liang; Huang, Cheng-Wei; Jang, Hung-Der

2015-01-01

To realize the feasibility of biodiesel production from high-lipid cell culture, microbial lipid production by the oleaginous yeasts was studied using glucose and sucrose as carbon source. Among the tested strains, Cryptococcus sp. SM5S05 accumulated the highest levels of intracellular lipids. The crude lipid contents of Cryptococcus sp. cultured in yeast malt agar reached 30% on a dry weight basis. The accumulation of lipids strongly depended on carbon/nitrogen ratio and nitrogen concentration. The highest content of lipids, measured at a carbon/nitrogen ratio of 60–90 and at a nitrogen concentration of 0.2%, was 60–57% lipids in the dry biomass. Batch cultures using corncob hydrolysate demonstrated that there was minimal inhibitory effect with a reducing sugar concentration of 60 g l −1 or higher. Batch cultures of Cryptococcus sp. SM5S05 in the corncob hydrolysate medium with 60 g l −1 glucose resulted in a dry biomass, lipid yields, and content of 12.6 g l −1 , 7.6 g l −1 , and 60.2%, respectively. The lipids contained mainly long-chain saturated and unsaturated fatty acids with 16 and 18 carbon atoms. The fatty acid profile of Cryptococcus oils was quite similar to that of conventional vegetable oil. The cost of lipid production could be further reduced with corncob hydrolysate being utilized as the raw material for the oleaginous yeast. The results showed that the microbial lipid from Cryptococcus sp. was a potential alternative resource for biodiesel production. - Highlights: • Microbial oil production from oleaginous yeast Cryptococcus sp. was studied. • Accumulation of lipid strongly depended on C/N ratio and nitrogen concentration. • Cultures in hydrolysate medium with 60 g/l glucose resulted in maximum lipid yields. • Maximal lipid content in the Cryptococcus sp. were 60.2% on dried weight basis

Ethanol production from biomass by repetitive solid-state fed-batch fermentation with continuous recovery of ethanol

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Moukamnerd, Churairat; Kino-oka, Masahiro; Sugiyama, Minetaka; Kaneko, Yoshinobu; Harashima, Satoshi; Katakura, Yoshio [Osaka Univ. (Japan). Dept. of Biotechnology; Boonchird, Chuenchit [Mahidol Univ., Bangkok (Thailand). Dept. of Biotechnology; Noda, Hideo [Kansai Chemical Engineering Co., Ltd., Amagasaki (Japan); Ninomiya, Kazuaki [Kanazawa Univ. (Japan). Inst. of International Environment Technology; Shioya, Suteaki [Sojo Univ., Kumamoto (Japan). Dept. of Applied Life Science

2010-09-15

To save cost and input energy for bioethanol production, a consolidated continuous solid-state fermentation system composed of a rotating drum reactor, a humidifier, and a condenser was developed. Biomass, saccharifying enzymes, yeast, and a minimum amount of water are introduced into the system. Ethanol produced by simultaneous saccharification and fermentation is continuously recovered as vapor from the headspace of the reactor, while the humidifier compensates for the water loss. From raw corn starch as a biomass model, 95 {+-} 3, 226 {+-} 9, 458 {+-} 26, and 509 {+-} 64 g l{sup -1} of ethanol solutions were recovered continuously when the ethanol content in reactor was controlled at 10-20, 30-50, 50-70 and 75-85 g kg-mixture{sup -1}, respectively. The residue showed a lesser volume and higher solid content than that obtained by conventional liquid fermentation. The cost and energy for intensive waste water treatment are decreased, and the continuous fermentation enabled the sustainability of enzyme activity and yeast in the system. (orig.)

[Biomass composition of thermotolerant yeasts of the genus Candida under elevated cultivation temperatures].

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Chistiakova, T I; Dediukhina, E G; Eroshin, V K

1981-01-01

The effect of growth temperature on the content of nucleic acids, the content and composition of protein, and the pool of free amino acids and lipids was studied under the conditions of chemostat cultivation of yeast strains at constant flow rates and pO2. The pool of free amino acids in all of the strains decreased with an increase in the temperature of growth. Changes in the content and composition of other cellular components depending on temperature were determined by individual characteristics of the strains. A linear relationship between the content of biomass components and the temperature of growth was found only in Candida scottii. The temperature of yeast cultivation may be used as a factor regulating the pool of free intracellular amino acids and the fatty acids composition of lipids.

Enhancement of ethanol fermentation in Saccharomyces cerevisiae sake yeast by disrupting mitophagy function.

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Shiroma, Shodai; Jayakody, Lahiru Niroshan; Horie, Kenta; Okamoto, Koji; Kitagaki, Hiroshi

2014-02-01

Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 has one of the highest fermentation rates among brewery yeasts used worldwide; therefore, it is assumed that it is not possible to enhance its fermentation rate. However, in this study, we found that fermentation by sake yeast can be enhanced by inhibiting mitophagy. We observed mitophagy in wild-type sake yeast during the brewing of Ginjo sake, but not when the mitophagy gene (ATG32) was disrupted. During sake brewing, the maximum rate of CO2 production and final ethanol concentration generated by the atg32Δ laboratory yeast mutant were 7.50% and 2.12% higher than those of the parent strain, respectively. This mutant exhibited an improved fermentation profile when cultured under limiting nutrient concentrations such as those used during Ginjo sake brewing as well as in minimal synthetic medium. The mutant produced ethanol at a concentration that was 2.76% higher than the parent strain, which has significant implications for industrial bioethanol production. The ethanol yield of the atg32Δ mutant was increased, and its biomass yield was decreased relative to the parent sake yeast strain, indicating that the atg32Δ mutant has acquired a high fermentation capability at the cost of decreasing biomass. Because natural biomass resources often lack sufficient nutrient levels for optimal fermentation, mitophagy may serve as an important target for improving the fermentative capacity of brewery yeasts.

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

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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.

The synergistic effects for the co-cultivation of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus on the biomass and total lipids accumulation.

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Yen, Hong-Wei; Chen, Pin-Wen; Chen, Li-Juan

2015-05-01

In this co-culture of oleaginous yeast-Rhodotorula glutinis and microalgae-Scenedesmus obliquus, microalgae potentially acts as an oxygen generator for the growth of aerobic yeast while the yeast mutually provides CO2 to the microalgae as both carry out the production of lipids. To explore the synergistic effects of co-cultivation on the cells growth and total lipids accumulation, several co-culture process parameters including the carbon source concentration, temperature and dissolved oxygen level would be firstly investigated in the flask trials. The results of co-culture in a 5L photobioreactor revealed that about 40-50% of biomass increased and 60-70% of total lipid increased was observed as compared to the single culture batches. Besides the synergistic effects of gas utilization, the providing of trace elements to each other after the natural cells lysis was believed to be another benefit to the growth of the overall co-culture system. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimizing a culture medium for biomass and phenolic compounds production using Ganoderma lucidum

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Carlos Andrés Zárate-Chaves

2013-01-01

Full Text Available The present work was aimed at optimizing a culture medium for biomass production and phenolic compounds by using Ganoderma lucidum. The culture was optimized in two stages; a Plackett-Burman design was used in the first one for identifying key components in the medium and a central composite design was used in the second one for optimizing their concentration. Both responses (biomass and phenolic compounds were simultaneously optimized by the latter methodology regarding desirability, and the optimal concentrations obtained were 50.00 g/L sucrose, 13.29 g/L yeast extract and 2.99 g/L olive oil. Maximum biomass production identified in these optimal conditions was 9.5 g/L and that for phenolic compounds was 0.0452 g/L, this being 100% better than that obtained in the media usually used in the laboratory. Similar patterns regarding chemical characterization and biological activity towards Aspergillus sp., from both fruiting body and mycelium-derived secondary metabolites and extracts obtained in the proposed medium were observed. It was shown that such statistical methodologies are useful for optimizing fermentation and, in the specific case of G. lucidum, optimizing processes for its production and its metabolites in submerged culture as an alternative to traditional culture.

Selection of oleaginous yeasts for fatty acid production

NARCIS (Netherlands)

Lamers, Dennis; Biezen, van Nick; Martens, Dirk; Peters, Linda; Zilver, van de Eric; Jacobs-van Dreumel, Nicole; Wijffels, René H.; Lokman, Christien

2016-01-01

Background: Oleaginous yeast species are an alternative for the production of lipids or triacylglycerides (TAGs). These yeasts are usually non-pathogenic and able to store TAGs ranging from 20 % to 70 % of their cell mass depending on culture conditions. TAGs originating from oleaginous yeasts

Fostering triacylglycerol accumulation in novel oleaginous yeast Cryptococcus psychrotolerans IITRFD utilizing groundnut shell for improved biodiesel production.

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Deeba, Farha; Pruthi, Vikas; Negi, Yuvraj S

2017-10-01

The investigation was carried out to examine the potential of triacylglycerol (TAG) accumulation by novel oleaginous yeast isolate Cryptococcus psychrotolerans IITRFD on utilizing groundnut shell acid hydrolysate (GSH) as cost-effective medium. The maximum biomass productivity and lipid productivity of 0.095±0.008g/L/h and 0.044±0.005g/L/h, respectively with lipid content 46% was recorded on GSH. Fatty acid methyl ester (FAME) profile obtained by GC-MS analysis revealed oleic acid (37.8%), palmitic (29.4%) and linoleic (32.8%) as major fatty acids representing balance between oxidative stability (OS) and cold flow filter properties (CFFP) for improved biodiesel quality. The biodiesel property calculated were correlated well with the fuel standards limits of ASTM D6751, EN 14214 and IS 15607. The present findings raise the possibility of using agricultural waste groundnut shell as a substrate for production of biodiesel by novel oleaginous yeast isolate C. psychrotolerans IITRFD. Copyright © 2017 Elsevier Ltd. All rights reserved.

Continuous production of pectinase by immobilized yeast cells on spent grains.

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Almeida, Catarina; Brányik, Tomás; Moradas-Ferreira, Pedro; Teixeira, José

2003-01-01

A yeast strain secreting endopolygalacturonase was used in this work to study the possibility of continuous production of this enzyme. It is a feasible and interesting alternative to fungal batch production essentially due to the specificity of the type of pectinase excreted by Kluyveromyces marxianus CCT 3172, to the lower broth viscosity and to the easier downstream operations. In order to increase the reactors' productivity, a cellulosic carrier obtained from barley spent grains was tested as an immobilization support. Two types of reactors were studied for pectinase production using glucose as a carbon and energy source--a continuous stirred tank reactor (CSTR) and a packed bed reactor (PBR) with recycled flow. The highest value for pectinase volumetric productivity (P(V)=0.98 U ml(-1) h(-1)) was achieved in the PBR for D=0.40 h(-1), a glucose concentration on the inlet of S(in)=20 g l(-1), and a biomass load in the support of X(i)=0.225 g g(-1). The results demonstrate the attractiveness of the packed bed system for pectinase production.

From potential to reality. Yeasts derived from ethanol production for animal nutrition

International Nuclear Information System (INIS)

Fernandes, E.A.N.; Trevizam, A.B.; Nepomuceno, N.; Amorim, H.V.

1998-01-01

The high costs of cereals and vegetable protein supplements used for animal nutrition have directed much attention toward non-conventional alternative protein sources. Brazil has a significant potential to provide such material, since it is the world's largest producer of ethanol (13 billion liters per year) derived from fermentation by yeasts (sugar cane being the basic raw material). Distilleries are recovering surplus yeast to produce dry yeast for use in animal food formulations. With regard to the yeast biomass elemental composition, INAA analyses performed on a pool of samples from various different fermentations have shown the presence of various trace elements, e.g. As, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Na, Rb, Sc, Sm, Th, and Zn. This reinforces the need for additional studies concerning the suitability of yeast in terms of maximum tolerable levels of these elements in formulations for domestic animals. (author)

One-step production of biocommodities from lignocellulosic biomass by recombinant cellulolytic bacillus subtilis: opportunities and challenges

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiao-Zhou [Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States); Zhang, Yi-Heng P. [Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States); Institute for Critical Technology and Applied Science, Virginia Polytechnic Institute and State University, Blacksburg, VA (United States); BioEnergy Science Center of Department of Energy, Oak Ridge, TN (United States)

2010-10-15

One-step consolidated bioprocessing that integrates cellulase production, cellulose hydrolysis, and product fermentation into a single step for decreasing costly cellulase use, increasing volumetric productivity, and reducing capital investment is widely accepted for low-cost production of biofuels or other value-added biochemicals. Considering the narrow margins between biomass and low-value biocommodities, good physiological performance of industrial microbes is crucial for economically viable production. Bacillus subtilis, the best-characterized Gram-positive microorganism, is a major industrial microorganism with numerous valuable features such as hexose and pentose utilization, low-nutrient needs, fast growth rate, high protein secretion capacity, industrial safety, etc. As compared with other potential consolidated bioprocessing microorganisms such as Clostridium spp., Escherichia coli, and the yeast Saccharomyces cerevisiae, recombinant cellulolytic B. subtilis strains would be a potential platform for biocommodity production from nonfood biomass. Here, we review the advances in recombinant cellulolytic B. subtilis development and metabolic engineering for biocommodity production, and discuss the opportunities and challenges of cellulolytic B. subtilis for biocommodity production. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Yeast synthetic biology for the production of recombinant therapeutic proteins.

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Kim, Hyunah; Yoo, Su Jin; Kang, Hyun Ah

2015-02-01

The production of recombinant therapeutic proteins is one of the fast-growing areas of molecular medicine and currently plays an important role in treatment of several diseases. Yeasts are unicellular eukaryotic microbial host cells that offer unique advantages in producing biopharmaceutical proteins. Yeasts are capable of robust growth on simple media, readily accommodate genetic modifications, and incorporate typical eukaryotic post-translational modifications. Saccharomyces cerevisiae is a traditional baker's yeast that has been used as a major host for the production of biopharmaceuticals; however, several nonconventional yeast species including Hansenula polymorpha, Pichia pastoris, and Yarrowia lipolytica have gained increasing attention as alternative hosts for the industrial production of recombinant proteins. In this review, we address the established and emerging genetic tools and host strains suitable for recombinant protein production in various yeast expression systems, particularly focusing on current efforts toward synthetic biology approaches in developing yeast cell factories for the production of therapeutic recombinant proteins. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Yarrowia lipolytica: a model yeast for citric acid production.

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Cavallo, Ema; Charreau, Hernán; Cerrutti, Patricia; Foresti, María Laura

2017-12-01

Every year more than 2 million tons of citric acid (CA) are produced around the world for industrial uses. Although initially extracted from citrus, the low profitability of the process and the increasing demand soon stimulated the search for more efficient methods to produce CA. Currently, most world CA demand (99%) is satisfied by fermentations with microorganisms, especially filamentous fungi and yeasts. CA production with yeasts has certain advantages over molds (e.g. higher productivity and easier cultivation), which in the last two decades have triggered a clear increase in publications and patents devoted to the use of yeasts in this field. Yarrowia lipolytica has become a model yeast that proved to be successful in different production systems. Considering the current interest evidenced in the literature, the most significant information on CA production using Y. lipolytica is summarized. The relevance on CA yields of key factors such as strains, media formulation, environmental conditions and production regimes is thoroughly discussed, with particular focus on increasing CA productivity. Besides, the possibility of tuning the mentioned variables to reduce concomitant isocitric acid production-the biggest disadvantage of using yeasts-is analyzed. Available methods for CA purification/quantification are also discussed. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach.

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Dong, Tao; Yu, Liang; Gao, Difeng; Yu, Xiaochen; Miao, Chao; Zheng, Yubin; Lian, Jieni; Li, Tingting; Chen, Shulin

2015-12-01

Accurate determination of fatty acid contents is routinely required in microalgal and yeast biofuel studies. A method of rapid in situ fatty acid methyl ester (FAME) derivatization directly from wet fresh microalgal and yeast biomass was developed in this study. This method does not require prior solvent extraction or dehydration. FAMEs were prepared with a sequential alkaline hydrolysis (15 min at 85 °C) and acidic esterification (15 min at 85 °C) process. The resulting FAMEs were extracted into n-hexane and analyzed using gas chromatography. The effects of each processing parameter (temperature, reaction time, and water content) upon the lipids quantification in the alkaline hydrolysis step were evaluated with a full factorial design. This method could tolerate water content up to 20% (v/v) in total reaction volume, which equaled up to 1.2 mL of water in biomass slurry (with 0.05-25 mg of fatty acid). There were no significant differences in FAME quantification (p>0.05) between the standard AOAC 991.39 method and the proposed wet in situ FAME preparation method. This fatty acid quantification method is applicable to fresh wet biomass of a wide range of microalgae and yeast species.

The use of a thermotolerant fermentative Kluyveromyces marxianus IMB3 yeast strain for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Banat, I.M. [Univ. of the United Arab Emirates, Al-Ain (United Arab Emirates). Dept. of Biolology; Singh, D. [Haryana Agriculture Univ., Hisar (India). Dept. of Microbiology; Marchant, R. [Ulster Univ. (United Kingdom). School of Applied Biological and Chemical Sciences

1996-12-31

An investigation was carried out on the growth and ethanol production of a novel thermotolerant ethanol-producing Kluyveromyces marxianus IMB3 yeast strain. It grew aerobically on glucose, lactose, cellobiose, xylose and whey permeate and fermented all the above carbon sources to ethanol at 45 C. This strain was capable of growing under anaerobic chemostat fermentation conditions at 45 C and a dilution rate of 0.15 h{sup -1} and produced {<=}0.9 g/l biomass and 1.8% (v/v) ethanol. An increase in biomass (up to 10.0 g/l) and ethanol (up to 4.3% v/v at 45 C and 7.7% v/v at 40 C) were achieved by applying a continuous two-stage fermentation in sequence (one aerobic and one anerobic stage) or a two-stage anaerobic fermentation with cell recycling. Potential applications, involving alcohol production systems, for use in dairy and wood related industries, were discussed. (orig.)

Biomass in Switzerland. Energy production

International Nuclear Information System (INIS)

Guggisberg, B.

2006-01-01

In the long term, biomass could be used for energy production in a three times more intensive way, compared to current figures. A major contribution would be delivered to Switzerland's energy supply. Numerous biomass conversion technologies do exist, for the production of heat, power or vehicle fuel. However, the implementation of such a large-scale utilisation of biomass requires a couple of strategic decisions in order to improve the framework conditions for biomass development and precisely target the supporting measures applicable to both research and pilot plants. In short, a clear and efficient strategy is necessary in what regards biomass, that will be used for the definition of a future catalogue of measures. (author)

Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.

Science.gov (United States)

Mekoue Nguela, Julie; Vernhet, Aude; Sieczkowski, Nathalie; Brillouet, Jean-Marc

2015-09-02

Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.

Advances in cellulosic conversion to fuels: engineering yeasts for cellulosic bioethanol and biodiesel production.

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Ko, Ja Kyong; Lee, Sun-Mi

2018-04-01

Cellulosic fuels are expected to have great potential industrial applications in the near future, but they still face technical challenges to become cost-competitive fuels, thus presenting many opportunities for improvement. The economical production of viable biofuels requires metabolic engineering of microbial platforms to convert cellulosic biomass into biofuels with high titers and yields. Fortunately, integrating traditional and novel engineering strategies with advanced engineering toolboxes has allowed the development of more robust microbial platforms, thus expanding substrate ranges. This review highlights recent trends in the metabolic engineering of microbial platforms, such as the industrial yeasts Saccharomyces cerevisiae and Yarrowia lipolytica, for the production of renewable fuels. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

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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).

Metabolic efficiency in yeast Saccharomyces cerevisiae in relation to temperature dependent growth and biomass yield.

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Zakhartsev, Maksim; Yang, Xuelian; Reuss, Matthias; Pörtner, Hans Otto

2015-08-01

Canonized view on temperature effects on growth rate of microorganisms is based on assumption of protein denaturation, which is not confirmed experimentally so far. We develop an alternative concept, which is based on view that limits of thermal tolerance are based on imbalance of cellular energy allocation. Therefore, we investigated growth suppression of yeast Saccharomyces cerevisiae in the supraoptimal temperature range (30-40°C), i.e. above optimal temperature (Topt). The maximal specific growth rate (μmax) of biomass, its concentration and yield on glucose (Yx/glc) were measured across the whole thermal window (5-40°C) of the yeast in batch anaerobic growth on glucose. Specific rate of glucose consumption, specific rate of glucose consumption for maintenance (mglc), true biomass yield on glucose (Yx/glc(true)), fractional conservation of substrate carbon in product and ATP yield on glucose (Yatp/glc) were estimated from the experimental data. There was a negative linear relationship between ATP, ADP and AMP concentrations and specific growth rate at any growth conditions, whilst the energy charge was always high (~0.83). There were two temperature regions where mglc differed 12-fold, which points to the existence of a 'low' (within 5-31°C) and a 'high' (within 33-40°C) metabolic mode regarding maintenance requirements. The rise from the low to high mode occurred at 31-32°C in step-wise manner and it was accompanied with onset of suppression of μmax. High mglc at supraoptimal temperatures indicates a significant reduction of scope for growth, due to high maintenance cost. Analysis of temperature dependencies of product formation efficiency and Yatp/glc revealed that the efficiency of energy metabolism approaches its lower limit at 26-31°C. This limit is reflected in the predetermined combination of Yx/glc(true), elemental biomass composition and degree of reduction of the growth substrate. Approaching the limit implies a reduction of the safety margin

Xylitol production from colombian native yeast strains

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Isleny Andrea Vanegas Córdoba

2004-07-01

Full Text Available Xylitol is an alternative sweetener with similar characteristics to sucrose that has become of great interest, due mainly to its safe use in diabetic patients and those deficient in glucose-6-phosphate-dehydrogenase. Its chemical production is expensive and generates undesirable by-products, whereas biotechnological process, which uses different yeasts genera, is a viable production alternative because it is safer and specific. Colombia has a privilege geographic location and offers a great microbial variety, this can be taken advantage of with academic and commercial goals. Because of this, some native microorganisms with potential to produce xylitol were screened in this work. It were isolated 25 yeasts species, from which was possible to identify 84% by the kit API 20C-AUX. Three yeasts: Candida kefyr, C. tropicalis y C. parapsilosis presented greater capacity to degrade xylose compared to the others, therefore they were selected for the later evaluation of its productive capacity. Discontinuous cellular cultures were developed in shaken flasks at 200 rpm and 35°C by 30 hours, using synthetic media with xylose as carbon source. Xylose consumption and xylitol production were evaluated by thin layer chromatography and high performance liquid chromatography. The maximal efficiency were obtained with Candida kefyr and C. tropicalis (Yp/s 0.5 y 0.43 g/g, respectively, using an initial xylose concentration of 20 g/L. Key words: Xylitol, xylose, yeasts, Candida kefyr, C. tropicalis, C. parapsilosis.

Using reaction-technical models for characterisation and optimisation of continuous ethanol production with biomass recirculation

Energy Technology Data Exchange (ETDEWEB)

Yayanata, Y

1983-11-28

Ethanol production from S. cerevisiae was studied experimentally in one- and two-stage plants, with and without biomass recirculation. The hydrogen sources were glucose and molasses. The experimental findings were used as a basis for mathematical models whose kinetic parameters were established by comparison with the experiments. In the fermentation processes with glucose as carbon and energy source, an activation kinetics of yeast extract was considered in addition to the limitations resulting from the substrate and the inhibition by the produced ethanol. The problem of biomass recirculation received particular attention. Lamellar separators in the form of a cated tube cluster are described as an alternative to conventional conical separator tanks. Biomass concentrations in the fermenter may amount to about 80 gTS/l. Satisfactory simulation of the plant behaviour is possible by combining the kinetic approaches for the fermenter with the mathematical models for the separator.

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.)

Development of a cultivation process for the enhancement of human interferon alpha 2b production in the oleaginous yeast, Yarrowia lipolytica

Directory of Open Access Journals (Sweden)

Gasmi Najla

2011-11-01

Full Text Available Abstract Background As an oleaginous yeast, Yarrowia lipolytica is able to assimilate hydrophobic substrates. This led to the isolation of several promoters of key enzymes of this catabolic pathway. Less is known about the behavior of Y. lipolytica in large bioreactors using these substrates. There is therefore a lack of established know-how concerning high cell density culture protocols of this yeast. Consequently, the establishment of suitable induction conditions is required, to maximize recombinant protein production under the control of these promoters. Results Human interferon α2b (huIFN α2b production in Yarrowia lipolytica was used as a model for the enhancement of recombinant protein production under the control of the oleic acid (OA-inducible promoter POX2. Cell viability and heterologous protein production were enhanced by exponential glucose feeding, to generate biomass before OA induction. The optimal biomass level before induction was determined (73 g L-1, and glucose was added with oleic acid during the induction phase. Several oleic acid feeding strategies were assessed. Continuous feeding with OA at a ratio of 0.02 g OA per g dry cell weight increased huIFNα2b production by a factor of 1.88 (425 mg L-1 and decreased the induction time (by a factor of 2.6, 21 h. huIFN α2b degradation by an aspartic protease secreted by Y. lipolytica was prevented by adding pepstatin (10 μM, leading to produce a 19-fold more active huIFN α2b (26.2 × 107 IU mg-1. Conclusion Y. lipolytica, a generally regarded as safe (GRAS microorganism is one of the most promising non conventional yeasts for the production of biologically active therapeutic proteins under the control of hydrophobic substrate-inducible promoter.

Fed-batch production of green coconut hydrolysates for high-gravity second-generation bioethanol fermentation with cellulosic yeast.

Science.gov (United States)

Soares, Jimmy; Demeke, Mekonnen M; Van de Velde, Miet; Foulquié-Moreno, Maria R; Kerstens, Dorien; Sels, Bert F; Verplaetse, Alex; Fernandes, Antonio Alberto Ribeiro; Thevelein, Johan M; Fernandes, Patricia Machado Bueno

2017-11-01

The residual biomass obtained from the production of Cocos nucifera L. (coconut) is a potential source of feedstock for bioethanol production. Even though coconut hydrolysates for ethanol production have previously been obtained, high-solid loads to obtain high sugar and ethanol levels remain a challenge. We investigated the use of a fed-batch regime in the production of sugar-rich hydrolysates from the green coconut fruit and its mesocarp. Fermentation of the hydrolysates obtained from green coconut or its mesocarp, containing 8.4 and 9.7% (w/v) sugar, resulted in 3.8 and 4.3% (v/v) ethanol, respectively. However, green coconut hydrolysate showed a prolonged fermentation lag phase. The inhibitor profile suggested that fatty acids and acetic acid were the main fermentation inhibitors. Therefore, a fed-batch regime with mild alkaline pretreatment followed by saccharification, is presented as a strategy for fermentation of such challenging biomass hydrolysates, even though further improvement of yeast inhibitor tolerance is also needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Yeasts in foods and beverages: impact on product quality and safety.

Science.gov (United States)

Fleet, Graham H

2007-04-01

The role of yeasts in food and beverage production extends beyond the well-known bread, beer and wine fermentations. Molecular analytical technologies have led to a major revision of yeast taxonomy, and have facilitated the ecological study of yeasts in many other products. The mechanisms by which yeasts grow in these ecosystems and impact on product quality can now be studied at the level of gene expression. Their growth and metabolic activities are moderated by a network of strain and species interactions, including interactions with bacteria and other fungi. Some yeasts have been developed as agents for the biocontrol of food spoilage fungi, and others are being considered as novel probiotic organisms. The association of yeasts with opportunistic infections and other adverse responses in humans raises new issues in the field of food safety.

Solving ethanol production problems with genetically modified yeast strains

Directory of Open Access Journals (Sweden)

A. Abreu-Cavalheiro

2013-09-01

Full Text Available The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Solving ethanol production problems with genetically modified yeast strains.

Science.gov (United States)

Abreu-Cavalheiro, A; Monteiro, G

2013-01-01

The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products) has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Production of methanol/DME from biomass

DEFF Research Database (Denmark)

Ahrenfeldt, Jesper; Henriksen, Ulrik Birk; Münster-Swendsen, Janus

In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier...... cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51...... gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic...

Potential of sustainable biomass production systems in Texas

International Nuclear Information System (INIS)

Sanderson, M.A.; Hussey, M.A.; Wiselogel, A.E.

1992-01-01

Biomass production for liquid fuels feedstock from systems based on warm-season perennial grasses (WSPG) offers a sustainable alternative for forage-livestock producers in Texas. Such systems also would enhance diversity and flexibility in current production systems. Research is needed to incorporate biomass production for liquid fuels, chemicals, and electrical power into current forage-livestock management systems. Our research objectives were to (i) document the potential of several WSPG in diverse Texas environments for biomass feedstock production, (ii) conduct fundamental research on morphological development of WSPG to enhance management for biomass feedstock production, (iii) examine current on-farm production systems for opportunities to incorporate biomass production, and (iv) determine feedstock quality and stability during storage

Hydrothermal decomposition of yeast cells for production of proteins and amino acids

Energy Technology Data Exchange (ETDEWEB)

Lamoolphak, Wiwat [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Goto, Motonobu [Department of Applied Chemistry and Biochemistry, Kumamoto University, Kumamoto 850-8555 (Japan); Sasaki, Mitsuru [Department of Applied Chemistry and Biochemistry, Kumamoto University, Kumamoto 850-8555 (Japan); Suphantharika, Manop [Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400 (Thailand); Muangnapoh, Chirakarn [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Prommuag, Chattip [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand); Shotipruk, Artiwan [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Patumwan, Payathai Road, Bangkok 10330 (Thailand)]. E-mail: artiwan.s@chula.ac.th

2006-10-11

This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 deg. C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 deg. C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 deg. C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products.

Hydrothermal decomposition of yeast cells for production of proteins and amino acids

International Nuclear Information System (INIS)

Lamoolphak, Wiwat; Goto, Motonobu; Sasaki, Mitsuru; Suphantharika, Manop; Muangnapoh, Chirakarn; Prommuag, Chattip; Shotipruk, Artiwan

2006-01-01

This study examines hydrothermal decomposition of Baker's yeast cells, used as a model for spent Brewer's yeast waste, into protein and amino acids. The reaction was carried out in a closed batch reactor at various temperatures between 100 and 250 deg. C. The reaction products were separated into water-soluble and solid residue. The results demonstrated that the amount of yeast residue decreased with increasing hydrolysis temperature. After 20 min reaction in water at 250 deg. C, 78% of yeast was decomposed. The highest amount of protein produced was also obtained at this condition and was found to be 0.16 mg/mg dry yeast. The highest amount of amino acids (0.063 mg/mg dry yeast) was found at the lowest temperature tested after 15 min. The hydrolysis product obtained at 200 deg. C was tested as a nutrient source for yeast growth. The growth of yeast cells in the culture medium containing 2 w/v% of this product was comparable to that of the cells grown in the medium containing commercial yeast extract at the same concentration. These results demonstrated the feasibility of using subcritical water to potentially decompose proteinaceous waste such as spent Brewer's yeast while recovering more useful products

Genome and metabolic engineering in non-conventional yeasts: Current advances and applications.

Science.gov (United States)

Löbs, Ann-Kathrin; Schwartz, Cory; Wheeldon, Ian

2017-09-01

Microbial production of chemicals and proteins from biomass-derived and waste sugar streams is a rapidly growing area of research and development. While the model yeast Saccharomyces cerevisia e is an excellent host for the conversion of glucose to ethanol, production of other chemicals from alternative substrates often requires extensive strain engineering. To avoid complex and intensive engineering of S. cerevisiae, other yeasts are often selected as hosts for bioprocessing based on their natural capacity to produce a desired product: for example, the efficient production and secretion of proteins, lipids, and primary metabolites that have value as commodity chemicals. Even when using yeasts with beneficial native phenotypes, metabolic engineering to increase yield, titer, and production rate is essential. The non-conventional yeasts Kluyveromyces lactis, K. marxianus, Scheffersomyces stipitis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris have been developed as eukaryotic hosts because of their desirable phenotypes, including thermotolerance, assimilation of diverse carbon sources, and high protein secretion. However, advanced metabolic engineering in these yeasts has been limited. This review outlines the challenges of using non-conventional yeasts for strain and pathway engineering, and discusses the developed solutions to these problems and the resulting applications in industrial biotechnology.

Occurrence and growth of yeasts in processed meat products - implications for potential spoilage

DEFF Research Database (Denmark)

Nielsen, Dennis Sandris; Jacobsen, Tomas; Jespersen, Lene

2008-01-01

of the processed meat products. The yeast microflora was complex with 4-12 different species isolated from the different production sites. In general, Candida zeylanoides, Debaryomyces hansenii and the newly described Candida alimentaria were found to be the dominant yeast species. In addition, three putatively......Spoilage of meat products is in general attributed to bacteria but new processing and storage techniques inhibiting growth of bacteria may provide opportunities for yeasts to dominate the microflora and cause spoilage of the product. With the aim of obtaining a deeper understanding of the potential...... role of yeast in spoilage of five different processed meat products (bacon, ham, salami and two different liver patés), yeasts were isolated, enumerated and identified during processing, in the final product and in the final product at the end of shelf life. Yeasts were isolated along the bacon...

The Slime Production by Yeasts Isolated from Subclinical Mastitic Cows

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Süheyla Türkyılmaz

2010-01-01

Full Text Available The aim of this study was to isolate yeasts from subclinical mastitic cows and to investigate the slime production by the isolated yeasts. The material used in this study included 339 milk samples from 152 dairy cattle with subclinical mastitis. Milk was plated onto blood agar, MacConkey agar and Sabouraud dextrose agar. Forty-one samples (12.1% of total milk samples were found positive for the yeast by API 20 C AUX identification system. The isolated yeasts were classified into four genera of Candida, Trichosporon, Cryptococcus and Saccharomyces. The Candida species were following: C. krusei, C. kefyr, C. guilliermondii, C. famata, C. rugosa and C. utulis. Other yeasts were identified as Trichosporon mucoides, T. asahii, Cryptococcus laurentii, C.  neoformans and Saccharomyces cerevisiae. Slime production was tested on Congo red brain heart infusion agar and evaluated according to Congo red phenomenon. Fifteen (36.6% strains were slime factor positive: seven were C. krusei, four C. kefyr, one C. guilliermondii, one C. famata, one T. asahii, and one C. laurentii. The results of the present study indicate that yeast mastitis is significant for causing economic losses and slime production is mostly found in non-albicans Candida species. Therefore, non-albicans Candida species should be examined for slime production.

METHOD FOR THE PRODUCTION OF HETEROLOGOUS POLYPEPTIDES IN TRANSFORMED YEAST CELLS

DEFF Research Database (Denmark)

2000-01-01

The invention describes industrial fermentation of a $i(Saccharomyces) yeast species for production of a heterologous product encoded by a plasmid or DNA contained in said $i(Saccharomyces) yeast species with method utilizes the substrate more efficiently and without fermentative metabolism...... resulting in formation of ethanol and other unwanted primary products of fermentative activity whereby high yields of the heterologous product are obtained. The $i(Saccharomyces) yeast species is preferably a Crabtree negative $i(Saccharomyces species) in particular $i(Saccharomyces kluyveri)....

Single cell oils of the cold-adapted oleaginous yeast Rhodotorula glacialis DBVPG 4785

Science.gov (United States)

2010-01-01

Background The production of microbial lipids has attracted considerable interest during the past decade since they can be successfully used to produce biodiesel by catalyzed transesterification with short chain alcohols. Certain yeast species, including several psychrophilic isolates, are oleaginous and accumulate lipids from 20 to 70% of biomass under appropriate cultivation conditions. Among them, Rhodotorula glacialis is a psychrophilic basidiomycetous species capable to accumulate intracellular lipids. Results Rhodotorula glacialis DBVPG 4785 is an oleaginous psychrophilic yeast isolated from a glacial environment. Despite its origin, the strain abundantly grew and accumulated lipids between -3 to 20°C. The temperature did not influence the yield coefficients of both biomass and lipids production, but had positive effect on the growth rate and thus on volumetric productivity of lipid. In glucose-based media, cellular multiplication occurred first, while the lipogenic phase followed whenever the culture was limited by a nutrient other than glucose. The extent of the carbon excess had positive effects on triacylglycerols production, that was maximum with 120 g L-1 glucose, in terms of lipid concentration (19 g L-1), lipid/biomass (68%) and lipid/glucose yields (16%). Both glucose concentration and growth temperature influenced the composition of fatty acids, whose unsaturation degree decreased when the temperature or glucose excess increased. Conclusions This study is the first proposed biotechnological application for Rhodotorula glacialis species, whose oleaginous biomass accumulates high amounts of lipids within a wide range of temperatures through appropriate cultivation C:N ratio. Although R. glacialis DBVPG 4785 is a cold adapted yeast, lipid production occurs over a broad range of temperatures and it can be considered an interesting microorganism for the production of single cell oils. PMID:20863365

Single cell oils of the cold-adapted oleaginous yeast Rhodotorula glacialis DBVPG 4785

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De Lucia Marzia

2010-09-01

Full Text Available Abstract Background The production of microbial lipids has attracted considerable interest during the past decade since they can be successfully used to produce biodiesel by catalyzed transesterification with short chain alcohols. Certain yeast species, including several psychrophilic isolates, are oleaginous and accumulate lipids from 20 to 70% of biomass under appropriate cultivation conditions. Among them, Rhodotorula glacialis is a psychrophilic basidiomycetous species capable to accumulate intracellular lipids. Results Rhodotorula glacialis DBVPG 4785 is an oleaginous psychrophilic yeast isolated from a glacial environment. Despite its origin, the strain abundantly grew and accumulated lipids between -3 to 20°C. The temperature did not influence the yield coefficients of both biomass and lipids production, but had positive effect on the growth rate and thus on volumetric productivity of lipid. In glucose-based media, cellular multiplication occurred first, while the lipogenic phase followed whenever the culture was limited by a nutrient other than glucose. The extent of the carbon excess had positive effects on triacylglycerols production, that was maximum with 120 g L-1 glucose, in terms of lipid concentration (19 g L-1, lipid/biomass (68% and lipid/glucose yields (16%. Both glucose concentration and growth temperature influenced the composition of fatty acids, whose unsaturation degree decreased when the temperature or glucose excess increased. Conclusions This study is the first proposed biotechnological application for Rhodotorula glacialis species, whose oleaginous biomass accumulates high amounts of lipids within a wide range of temperatures through appropriate cultivation C:N ratio. Although R. glacialis DBVPG 4785 is a cold adapted yeast, lipid production occurs over a broad range of temperatures and it can be considered an interesting microorganism for the production of single cell oils.

Selection of oleaginous yeasts for fatty acid production.

Science.gov (United States)

Lamers, Dennis; van Biezen, Nick; Martens, Dirk; Peters, Linda; van de Zilver, Eric; Jacobs-van Dreumel, Nicole; Wijffels, René H; Lokman, Christien

2016-05-27

Oleaginous yeast species are an alternative for the production of lipids or triacylglycerides (TAGs). These yeasts are usually non-pathogenic and able to store TAGs ranging from 20 % to 70 % of their cell mass depending on culture conditions. TAGs originating from oleaginous yeasts can be used as the so-called second generation biofuels, which are based on non-food competing "waste carbon sources". In this study the selection of potentially new interesting oleaginous yeast strains is described. Important selection criteria were: a broad maximum temperature and pH range for growth (robustness of the strain), a broad spectrum of carbon sources that can be metabolized (preferably including C-5 sugars), a high total fatty acid content in combination with a low glycogen content and genetic accessibility. Based on these selection criteria, among 24 screened species, Schwanniomyces occidentalis (Debaromyces occidentalis) CBS2864 was selected as a promising strain for the production of high amounts of lipids.

Selection and identification of oleaginous yeast isolated from soil, animal feed and ruminal fluid for use as feed supplement in dairy cattle.

Science.gov (United States)

Paserakung, A; Pattarajinda, V; Vichitphan, K; Froetschel, M A

2015-10-01

The purpose of this study was to select oleaginous yeast for microbial lipid production. Sixty-four yeast isolates were obtained from soil (GSY1-12), animal feeds (FDY1-21), and ruminal fluid (RMY1-31) using yeast extract peptone dextrose (YPD) agar. The cultivation of these isolates on nitrogen limited-medium revealed that GSY2 to GSY6, GSY10, FDY2, FDY12 and FDY14 accumulated lipid over 20% of dry biomass. Therefore, they were preliminarily classified as oleaginous yeast. In subsequent experiment, an 8 × 3 factorial in completely randomized design was conducted to examine the effect of eight oleaginous yeast strains and three nitrogen sources (peptone, (NH4 )2 SO4 , urea) on lipid accumulation when using molasses as substrate. The result illustrated that only GSY3 and GSY10 accumulated lipid over 20% of biomass when using peptone or (NH4 )2 SO4 but urea did not. However, GSY10 gave higher biomass and lipid yield than GSY3 (P yeast for microbial lipid production from molasses. This study illustrated the ability of T. asahii GSY10 to utilize molasses and (NH4 )2 SO4 for synthesizing and accumulating cellular lipid of which oleic acid (C18:1 ) was predominant. This yeast would be used for microbial lipid production used as feed supplement in dairy cattle. © 2015 The Society for Applied Microbiology.

Yeast diversity and dynamics in the production processes of Norwegian dry-cured meat products.

Science.gov (United States)

Asefa, Dereje T; Møretrø, Trond; Gjerde, Ragnhild O; Langsrud, Solveig; Kure, Cathrine F; Sidhu, Maan S; Nesbakken, Truls; Skaar, Ida

2009-07-31

This study investigate the diversity and dynamics of yeasts in the production processes of one unsmoked and two smoked dry-cured meat products of a Norwegian dry-cured meat production facility. A longitudinal observational study was performed to collect 642 samples from the meat, production materials, room installations and indoor and outdoor air of the production facility. Nutrient rich agar media were used to isolate the yeasts. Morphologically different isolates were re-cultivated in their pure culture forms. Both classical and molecular methods were employed for species identification. Totally, 401 yeast isolates belonging to 10 species of the following six genera were identified: Debaryomyces, Candida, Rhodotorula, Rhodosporidium, Cryptococcus and Sporidiobolus. Debaryomyces hansenii and Candida zeylanoides were dominant and contributed by 63.0% and 26.4% respectively to the total isolates recovered from both smoked and unsmoked products. The yeast diversity was higher at the pre-salting production processes with C. zeylanoides being the dominant. Later at the post-salting stages, D. hansenii occurred frequently. Laboratory studies showed that D. hansenii was more tolerant to sodium chloride and nitrite than C. zeylanoides. Smoking seems to have a killing or a temporary growth inhibiting effect on yeasts that extend to the start of the drying process. Yeasts were isolated only from 31.1% of the environmental samples. They belonged to six different species of which five of them were isolated from the meat samples too. Debaryomyces hansenii and Rhodotorula glutinis were dominant with a 62.6% and 22.0% contribution respectively. As none of the air samples contained D. hansenii, the production materials and room installations used in the production processes were believed to be the sources of contamination. The dominance of D. hansenii late in the production process replacing C. zeylanoides should be considered as a positive change both for the quality and safety

Characterization of wine yeasts for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Jimenez, J.; Benitez, T.

1986-11-01

Selected wine yeasts were tested for their ethanol and sugar tolerance, and for their fermentative capacity. Growth (..mu..) and fermentation rates (..nu..) were increasingly inhibited by increasing ethanol and glucose concentrations, ''flor'' yeasts being the least inhibited. Except in the latter strains, the ethanol production rate was accelerated by adding the glucose stepwise. The best fermenting strains selected in laboratory medium were also the best at fermenting molasses. Invertase activity was not a limiting step in ethanol production, ..nu.. being accelerated by supplementing molasses with ammonia and biotine, and by cell recycle.

Cyanobacterial biomass as carbohydrate and nutrient feedstock for bioethanol production by yeast fermentation

DEFF Research Database (Denmark)

Möllers, K Benedikt; Canella, D.; Jørgensen, Henning

2014-01-01

cyanobacterium Synechococcus sp. PCC 7002 was fermented using yeast into bioethanol. Results: The cyanobacterium accumulated a total carbohydrate content of about 60% of cell dry weight when cultivated under nitrate limitation. The cyanobacterial cells were harvested by centrifugation and subjected to enzymatic...... cyanobacteria or microalgae. Importantly, as well as fermentable carbohydrates, the cyanobacterial hydrolysate contained additional nutrients that promoted fermentation. This hydrolysate is therefore a promising substitute for the relatively expensive nutrient additives (such as yeast extract) commonly used...... hydrolysis using lysozyme and two alpha-glucanases. This enzymatic hydrolysate was fermented into ethanol by Saccharomyces cerevisiae without further treatment. All enzyme treatments and fermentations were carried out in the residual growth medium of the cyanobacteria with the only modification being that p...

Production of biopharmaceutical proteins by yeast: Advances through metabolic engineering

DEFF Research Database (Denmark)

Nielsen, Jens

2013-01-01

Production of recombinant proteins for use as pharmaceuticals, so-called biopharmaceuticals, is a multi-billion dollar industry. Many different cell factories are used for the production of biopharmaceuticals, but the yeast Saccharomyces cerevisiae is an important cell factory as it is used for p...... production. The involvement of directed metabolic engineering through the integration of tools from genetic engineering, systems biology and mathematical modeling, is also discussed....... by yeast are human serum albumin, hepatitis vaccines and virus like particles used for vaccination against human papillomavirus. Here is given a brief overview of biopharmaceutical production by yeast and it is discussed how the secretory pathway can be engineered to ensure more efficient protein...

Low-Frequency Electrochemical Impedance Spectroscopy as a Monitoring Tool for Yeast Growth in Industrial Brewing Processes

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Christoph Slouka

2017-08-01

Full Text Available Today’s yeast total biomass and viability measurements during the brewing process are dependent on offline methods such as methylene blue or florescence dye-based staining, and/or the usage of flow cytometric measurements. Additionally, microscopic cell counting methods decelerate an easy and quick prediction of yeast viability. These processes are time consuming and result in a time-delayed response signal, which not only reduces the knowledge of the performance of the yeast itself, but also impacts the quality of the final product. Novel approaches in process monitoring during the aerobic and anaerobic fermentation of Saccharomyces cerevisiae are not only limited to classical pH, dO2 and off-gas analysis, but they also use different in situ and online sensors based on different physical principles to determine the biomass, product quality and cell death. Within this contribution, electrochemical impedance spectroscopy (EIS was used to monitor the biomass produced in aerobic and anaerobic batch cultivation approaches, simulating the propagation and fermentation unit operation of industrial brewing processes. Increases in the double-layer capacitance (CDL, determined at frequencies below 1 kHz, were proportional to the increase of biomass in the batch, which was monitored in the online and inline mode. A good correlation of CDL with the cell density was found. In order to prove the robustness and flexibility of this novel method, different state-of-the-art biomass measurements (dry cell weight—DCW and optical density—OD were performed for comparison. Because measurements in this frequency range are largely determined by the double-layer region between the electrode and media, rather minor interferences with process parameters (aeration and stirring were to be expected. It is shown that impedance spectroscopy at low frequencies is not only a powerful tool for the monitoring of viable yeast cell concentrations during operation, but it is

The occurrence of spoilage yeasts in cream-filled bakery products.

Science.gov (United States)

Osimani, Andrea; Milanović, Vesna; Taccari, Manuela; Cardinali, Federica; Pasquini, Marina; Aquilanti, Lucia; Clementi, Francesca

2017-04-01

Filling creams can provide an adequate substrate for spoilage yeasts because some yeasts can tolerate the high osmotic stress in these products. To discover the source of spoilage of a cream-filled baked product, end products, raw materials, indoor air and work surfaces were subjected to microbiological and molecular analyses. The efficacy of disinfectants against spoilage yeasts was also assessed. The analyses on end products revealed the presence of the closest relatives to Zygosaccharomyces bailii with counts ranging from 1.40 to 4.72 log cfu g -1 . No spoilage yeasts were found in the indoor air and work surfaces. Polymerase chain reaction-denaturing gradient gel electrophoresis analysis, carried out directly on filling creams collected from unopened cans, showed the presence of bands ascribed to the closest relatives to Z. bailii sensu lato, although with counts products, reliable and sensitive methods must be used. Moreover, hygiene and the application of good manufacturing practices represent the most efficient way for the prevention and minimization of cross-contamination. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Economic analysis of biomass crop production in Florida

Energy Technology Data Exchange (ETDEWEB)

Rahmani, M.; Hodges, A.W.; Stricker, J.A.; Kiker, C.F. [University of Florida, Gainesville, FL (United States)

1997-07-01

Favorable soil and climate conditions for production of biomass crops in Florida, and a market for their use, provide the essentials for developing a biomass energy system in the State. Recent surveys showed that there is low opportunity cost land available and several high yield herbaceous and woody crops have potential as biomass crops. Comparison of biomass crop yields, farmgate costs, and costs of final products in Florida and other states show that Florida can be considered as one of the best areas for development of biomass energy systems in the United States. This paper presents facts and figures on biomass production and conversion in Florida and addresses issues of concern to the economics of biomass energy in the State. (author)

Economic analysis of biomass crop production in Florida

International Nuclear Information System (INIS)

Rahmani, M.; Hodges, A.W.; Stricker, J.A.; Kiker, C.F.

1997-01-01

Favorable soil and climate conditions for production of biomass crops in Florida, and a market for their use, provide the essentials for developing a biomass energy system in the State. Recent surveys showed that there is low opportunity cost land available and several high yield herbaceous and woody crops have potential as biomass crops. Comparison of biomass crop yields, farmgate costs, and costs of final products in Florida and other states show that Florida can be considered as one of the best areas for development of biomass energy systems in the United States. This paper presents facts and figures on biomass production and conversion in Florida and addresses issues of concern to the economics of biomass energy in the State. (author)

Sustainable biomass production for energy in Sri Lanka

International Nuclear Information System (INIS)

Perera, K.K.C.K.; Rathnasiri, P.G.; Sugathapala, A.G.T.

2003-01-01

The present study concentrates mainly on the estimation of land availability for biomass production and the estimation of sustainable biomass production potential for energy. The feasible surplus land area available for bioenergy plantation is estimated assuming two land availability scenarios (Scenarios 1 and 2) and three biomass demand scenarios (IBD Scenario, SBD Scenario and FBD Scenario). Scenario 1 assumes that 100% of the surplus area available in base year 1997 will be suitable for plantation without considering population growth and food production and that 75% of this surplus land is feasible for plantation. Scenario 2 assumes that future food requirement will grow by 20% and the potential surplus area will be reduced by that amount. The incremental biomass demand scenario (IBD Scenario) assumes that only the incremental demand for biomass in the year 2010 with respect to the base year 1997 has to be produced from new plantation. The sustainable biomass demand scenario (SBD Scenario) assumes that the total sustainable supply of biomass in 1997 is deducted from the future biomass demand in 2010 and only the balance is to be met by new plantation. The full biomass demand scenario (FBD Scenario) assumes that the entire projected biomass demand of the year 2010 needs to be produced from new plantation. The total feasible land area for the scenarios IBD-1, 1BD-2, SBD-1, SBD-2, FBD-1 and FBD-2 are approximately 0.96, 0.66, 0.80, 0.94, 0.60 and 0.30 Mha, respectively. Biomass production potential is estimated by selecting appropriate plant species, plantation spacing and productivity level. The results show that the total annual biomass production in the country could vary from 2 to 9.9 Mt. With the production option (i.e. 1.5 mx1.5 m spacing plantation with fertilizer application) giving the highest yield, the total biomass production for energy under IBD Scenario would be 9.9 Mt yr -1 for Scenario 1 and 6.7 Mt yr -1 for Scenario 2. Under SBD Scenario, the

Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals.

Science.gov (United States)

Borodina, Irina; Nielsen, Jens

2014-05-01

Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology and the advances in yeast strain engineering will stimulate development of novel yeast-based processes for chemicals production. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metabolic Engineering of Oleaginous Yeasts for Production of Fuels and Chemicals

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Shuobo Shi

2017-11-01

Full Text Available Oleaginous yeasts have been increasingly explored for production of chemicals and fuels via metabolic engineering. Particularly, there is a growing interest in using oleaginous yeasts for the synthesis of lipid-related products due to their high lipogenesis capability, robustness, and ability to utilize a variety of substrates. Most of the metabolic engineering studies in oleaginous yeasts focused on Yarrowia that already has plenty of genetic engineering tools. However, recent advances in systems biology and synthetic biology have provided new strategies and tools to engineer those oleaginous yeasts that have naturally high lipid accumulation but lack genetic tools, such as Rhodosporidium, Trichosporon, and Lipomyces. This review highlights recent accomplishments in metabolic engineering of oleaginous yeasts and recent advances in the development of genetic engineering tools in oleaginous yeasts within the last 3 years.

Pyrolysis of biomass for hydrogen production

International Nuclear Information System (INIS)

Constantinescu, Marius; David, Elena; Bucura, Felicia; Sisu, Claudia; Niculescu, Violeta

2006-01-01

Biomass processing is a new technology within the area of renewable energies. Current energy supplies in the world are dominated by fossil fuels (some 80% of the total use of over 400 EJ per year). Nevertheless, about 10-15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. On average, in the industrialized countries biomass contributes some 9-13% to the total energy supplies, but in developing countries the proportion is as high as a fifth to one third. In quite a number of countries biomass covers even over 50 to 90% of the total energy demand. Classic application of biomass combustion is heat production for domestic applications. A key issue for bio-energy is that its use should be modernized to fit into a sustainable development path. Especially promising are the production of electricity via advanced conversion concepts (i.e. gasification and state-of-the-art combustion and co-firing) and modern biomass derived fuels like methanol, hydrogen and ethanol from ligno-cellulosic biomass, which can reach competitive cost levels within 1-2 decades (partly depending on price developments with petroleum). (authors)

Yeast selection for fuel ethanol production in Brazil.

Science.gov (United States)

Basso, Luiz C; de Amorim, Henrique V; de Oliveira, Antonio J; Lopes, Mario L

2008-11-01

Brazil is one of the largest ethanol biofuel producers and exporters in the world and its production has increased steadily during the last three decades. The increasing efficiency of Brazilian ethanol plants has been evident due to the many technological contributions. As far as yeast is concerned, few publications are available regarding the industrial fermentation processes in Brazil. The present paper reports on a yeast selection program performed during the last 12 years aimed at selecting Saccharomyces cerevisiae strains suitable for fermentation of sugar cane substrates (cane juice and molasses) with cell recycle, as it is conducted in Brazilian bioethanol plants. As a result, some evidence is presented showing the positive impact of selected yeast strains in increasing ethanol yield and reducing production costs, due to their higher fermentation performance (high ethanol yield, reduced glycerol and foam formation, maintenance of high viability during recycling and very high implantation capability into industrial fermenters). Results also suggest that the great yeast biodiversity found in distillery environments could be an important source of strains. This is because during yeast cell recycling, selective pressure (an adaptive evolution) is imposed on cells, leading to strains with higher tolerance to the stressful conditions of the industrial fermentation.

Production of fuel ethanol from molasses by thermotolerant yeast

International Nuclear Information System (INIS)

Hamad, S. H.

2009-01-01

A thermotolerant strain of the yeast Kluyveromyces marxians, isolated from Kenana sugar factory in the Sudan, was used for the production of ethanol from molasses. Fermentations were carried out in a bioreactor with 10-litre working volume at three temperatures and three sugar concentrations in batch and at one temperature and three feeding rates in fed-batch processes. In the batch fermentations, the best results were obtained at 40 o C and 20% sugar, where a maximum of 9.2% (w/v) ethanol concentration was produced in 30 hours with a yield of 90% of the theoretical and a maximum ethanol specific productivity of 0.65 g per gramme yeast and hour. In the fed-batch process at 40 o C , the best results were obtained at 0.5 1/h feeding rate of a substrate with 400 g/1 sugar. Under such conditions, the yeast produced up to 9.34% (w/v) ethanol with 91.6% of the theoretical yield in 14 hours of fermentation and a maximum specific ethanol productivity of 0.9 g per gramme yeast and hour. (Author)

Engineering yeast metabolism for production of fuels and chemicals

DEFF Research Database (Denmark)

Nielsen, Jens

2016-01-01

faster development of metabolically engineered strains that can be used for production of fuels and chemicals. The yeast Saccharomyces cerevisiae is widely used for production of fuels, chemicals, pharmaceuticals and materials. Through metabolic engineering of this yeast a number of novel industrial...... as for metabolic design. In this lecture it will be demonstrated how the Design-Build-Test cycle of metabolic engineering has allowed for development of yeast cell factories for production of a range of different fuels and chemicals. Some examples of different technologies will be presented together with examples......Metabolic engineering relies on the Design-Build-Test cycle. This cycle includes technologies like mathematical modeling of metabolism, genome editing and advanced tools for phenotypic characterization. In recent years there have been advances in several of these technologies, which has enabled...

Potentials for forest woody biomass production in Serbia

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Vasiljević Aleksandar Lj.

2015-01-01

Full Text Available The paper presents the analysis of possible potentials for the production of forest biomass in Serbia taking into consideration the condition of forests, present organizational and technical capacities as well as the needs and situation on the firewood market. Starting point for the estimation of production potentials for forest biomass is the condition of forests which is analyzed based on the available planning documents on all levels. Potentials for biomass production and use refer to initial periods in the production and use of forest biomass in Serbia.

Genome and metabolic engineering in non-conventional yeasts: Current advances and applications

Directory of Open Access Journals (Sweden)

Ann-Kathrin Löbs

2017-09-01

Full Text Available Microbial production of chemicals and proteins from biomass-derived and waste sugar streams is a rapidly growing area of research and development. While the model yeast Saccharomyces cerevisiae is an excellent host for the conversion of glucose to ethanol, production of other chemicals from alternative substrates often requires extensive strain engineering. To avoid complex and intensive engineering of S. cerevisiae, other yeasts are often selected as hosts for bioprocessing based on their natural capacity to produce a desired product: for example, the efficient production and secretion of proteins, lipids, and primary metabolites that have value as commodity chemicals. Even when using yeasts with beneficial native phenotypes, metabolic engineering to increase yield, titer, and production rate is essential. The non-conventional yeasts Kluyveromyces lactis, K. marxianus, Scheffersomyces stipitis, Yarrowia lipolytica, Hansenula polymorpha and Pichia pastoris have been developed as eukaryotic hosts because of their desirable phenotypes, including thermotolerance, assimilation of diverse carbon sources, and high protein secretion. However, advanced metabolic engineering in these yeasts has been limited. This review outlines the challenges of using non-conventional yeasts for strain and pathway engineering, and discusses the developed solutions to these problems and the resulting applications in industrial biotechnology.

Microbial Biodiesel Production by Direct Transesterification of Rhodotorula glutinis Biomass

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I-Ching Kuan

2018-04-01

Full Text Available (1 Background: Lipids derived from oleaginous microbes have become promising alternative feedstocks for biodiesel. This is mainly because the lipid production rate from microbes is one to two orders of magnitude higher than those of energy crops. However, the conventional process for converting these lipids to biodiesel still requires a large amount of energy and organic solvents; (2 Methods: In this study, an oleaginous yeast, Rhodotorula glutinis, was used for direct transesterification without lipid pre-extraction to produce biodiesel, using sulfuric acid or sodium hydroxide as a catalyst. Such processes decreased the amount of energy and organic solvents required simultaneously; (3 Results: When 1 g of dry R. glutinis biomass was subject to direct transesterification in 20 mL of methanol catalyzed by 0.6 M H2SO4 at 70 °C for 20 h, the fatty acid methyl ester (FAME yield reached 111%. Using the same amount of biomass and methanol loading but catalyzed by 1 g/L NaOH at 70 °C for 10 h, the FAME yield reached 102%. The acid-catalyzed process showed a superior moisture tolerance; when the biomass contained 70% moisture, the FAME yield was 43% as opposed to 34% of the base-catalyzed counterpart; (4 Conclusions: Compared to conventional transesterification, which requires lipid pre-extraction, direct transesterification not only simplifies the process and shortens the reaction time, but also improves the FAME yield.

Production of methanol/DME from biomass

Energy Technology Data Exchange (ETDEWEB)

Ahrenfeldt, J.; Birk Henriksen, U.; Muenster-Swendsen, J.; Fink, A.; Roengaard Clausen, L.; Munkholt Christensen, J.; Qin, K.; Lin, W.; Arendt Jensen, P.; Degn Jensen, A.

2011-07-01

In this project the production of DME/methanol from biomass has been investigated. Production of DME/methanol from biomass requires the use of a gasifier to transform the solid fuel to a synthesis gas (syngas) - this syngas can then be catalytically converted to DME/methanol. Two different gasifier types have been investigated in this project: 1) The Two-Stage Gasifier (Viking Gasifier), designed to produce a very clean gas to be used in a gas engine, has been connected to a lab-scale methanol plant, to prove that the gas from the gasifier could be used for methanol production with a minimum of gas cleaning. This was proved by experiments. Thermodynamic computer models of DME and methanol plants based on using the Two-Stage Gasification concept were created to show the potential of such plants. The models showed that the potential biomass to DME/methanol + net electricity energy efficiency was 51-58% (LHV). By using waste heat from the plants for district heating, the total energy efficiencies could reach 87-88% (LHV). 2) A lab-scale electrically heated entrained flow gasifier has been used to gasify wood and straw. Entrained flow gasifiers are today the preferred gasifier type for commercial coal gasification, but little information exists on using these types of gasifiers for biomass gasification. The experiments performed provided quantitative data on product and gas composition as a function of operation conditions. Biomass can be gasified with less oxygen consumption compared to coal. The organic fraction of the biomass that is not converted to gas appears as soot. Thermodynamic computer models of DME and methanol plants based on using entrained flow gasification were created to show the potential of such plants. These models showed that the potential torrefied biomass to DME/methanol + net electricity energy efficiency was 65-71% (LHV). Different routes to produce liquid transport fuels from biomass are possible. They include production of RME (rapeseed oil

The availability of biomass for energy production

International Nuclear Information System (INIS)

Zeevalkink, J.A.; Borsboom, N.W.J.; Sikkema, R.

1997-12-01

The Dutch energy policy aims at 75 PJ energy production from biomass in the Netherlands by the year 2020. This requires the development of a biomass market for biomass fuels so that suppliers as well as users can sell and buy biomass, respectively. The study concentrates on the contribution that information about biomass supply and demand can make to the realization of such a market for biomass fuels and stimulating its functioning. During the study, an inventory was made of public information on biomass quantities that are expected to become available for energy production in the short term. It was proposed to set up a database that contains information about the supply and suppliers of forest wood (specifically thinnings), (clean) waste wood from wood-processing industries, used timber and green wood waste from public parks. On the basis of rough estimates it can be concluded that these biomass flows account for an approximate annual quantity of 900,000 tonnes of dry biomass, or an annual 16,000 W energy production. This quantity would cover 66% of the goal set for the year 2000 and 20% of the goal set for 2020. Various database models were described and discussed during a workshop which was organized for potentially interested parties so as to find out their interest in and potential support for such an information system. Though the results of the survey conducted earlier suggested otherwise, it turned out that there was only minor interest in an information system, i.e. there was an interest in a survey of the companies involved in biomass supply and demand. In addition, most parties preferred bilateral confidential contacts to contract biomass. The opinion of many parties was that Novem's major tasks were to characterize biomass quality, and to give support to the discussions about the legal framework for using (waste) wood for energy production. It was concluded that at this moment a database must not be set up; in the future, however, there could be a

Metabolic engineering of yeast for fermentative production of flavonoids

DEFF Research Database (Denmark)

Rodriguez Prado, Edith Angelica; Strucko, Tomas; Stahlhut, Steen Gustav

2017-01-01

Yeast Saccharomyces cerevisiae was engineered for de novo production of six different flavonoids (naringenin, liquiritigenin, kaempferol, resokaempferol, quercetin, and fisetin) directly from glucose, without supplementation of expensive intermediates. This required reconstruction of long...... demonstrates the potential of flavonoid-producing yeast cell factories....

Enhancement of carotenoids and lipids production by oleaginous red yeast Sporidiobolus pararoseus KM281507.

Science.gov (United States)

Chaiyaso, Thanongsak; Manowattana, Atchara

2018-01-02

Bioconversion of biodiesel-derived crude glycerol into carotenoids and lipids was investigated by a microbial conversion of an oleaginous red yeast Sporidiobolus pararoseus KM281507. The methanol content in crude glycerol (0.5%, w/v) did not show a significant effect on biomass production by strain KM281507. However, demethanolized crude glycerol significantly supported the production of biomass (8.64 ± 0.13 g/L), lipids (2.92 ± 0.03 g/L), β-carotene (15.76 ± 0.85 mg/L), and total carotenoids (33.67 ± 1.28 mg/L). The optimal conditions suggested by central composite design were crude glycerol concentration (55.04 g/L), initial pH of medium (pH 5.63) and cultivation temperature (24.01°C). Under these conditions, the production of biomass, lipids, β-carotene, and total carotenoids were elevated up to 8.83 ± 0.05, 4.00 ± 0.06 g/L, 27.41 ± 0.20, and 53.70 ± 0.48 mg/L, respectively. Moreover, an addition of olive oil (0.5 - 2.0%) dramatically increased the production of biomass (14.47 ± 0.15 g/L), lipids (6.40 ± 0.09 g/L), β-carotene (54.43 ± 0.95 mg/L), and total carotenoids (70.92 ± 0.51 mg/L). The oleic acid content in lipids was also increased to 75.1% (w/w) of total fatty acids, indicating a good potential to be an alternative biodiesel feedstock. Meanwhile, the β-carotene content in total carotenoids was increased to 76.7% (w/w). Hence, strain KM281507 could be a good potential source of renewable biodiesel feedstock and natural carotenoids.

The Prospects of Rubberwood Biomass Energy Production in Malaysia

Directory of Open Access Journals (Sweden)

Jegatheswaran Ratnasingam

2015-03-01

Full Text Available Rubber has been shown to be one of the most important plantation crops in Malaysia, and rubber tree biomass has widespread applications in almost all sectors of the wood products manufacturing sector. Despite its abundance, the exploitation of rubberwood biomass for energy generation is limited when compared to other available biomass such as oil palm, rice husk, cocoa, sugarcane, coconut, and other wood residues. Furthermore, the use of biomass for energy generation is still in its early stages in Malaysia, a nation still highly dependent on fossil fuels for energy production. The constraints for large scale biomass energy production in Malaysia are the lack of financing for such projects, the need for large investments, and the limited research and development activities in the sector of efficient biomass energy production. The relatively low cost of energy in Malaysia, through the provision of subsidy, also restricts the potential utilization of biomass for energy production. In order to fully realize the potential of biomass energy in Malaysia, the environmental cost must be factored into the cost of energy production.

Yeast-yeast interactions revealed by aromatic profile analysis of Sauvignon Blanc wine fermented by single or co-culture of non-Saccharomyces and Saccharomyces yeasts.

Science.gov (United States)

Sadoudi, Mohand; Tourdot-Maréchal, Raphaëlle; Rousseaux, Sandrine; Steyer, Damien; Gallardo-Chacón, Joan-Josep; Ballester, Jordi; Vichi, Stefania; Guérin-Schneider, Rémi; Caixach, Josep; Alexandre, Hervé

2012-12-01

There has been increasing interest in the use of selected non-Saccharomyces yeasts in co-culture with Saccharomyces cerevisiae. The main reason is that the multistarter fermentation process is thought to simulate indigenous fermentation, thus increasing wine aroma complexity while avoiding the risks linked to natural fermentation. However, multistarter fermentation is characterised by complex and largely unknown interactions between yeasts. Consequently the resulting wine quality is rather unpredictable. In order to better understand the interactions that take place between non-Saccharomyces and Saccharomyces yeasts during alcoholic fermentation, we analysed the volatile profiles of several mono-culture and co-cultures. Candida zemplinina, Torulaspora delbrueckii and Metschnikowia pulcherrima were used to conduct fermentations either in mono-culture or in co-culture with S. cerevisiae. Up to 48 volatile compounds belonging to different chemical families were quantified. For the first time, we show that C. zemplinina is a strong producer of terpenes and lactones. We demonstrate by means of multivariate analysis that different interactions exist between the co-cultures studied. We observed a synergistic effect on aromatic compound production when M. pulcherrima was in co-culture with S. cerevisiae. However a negative interaction was observed between C. zemplinina and S. cerevisiae, which resulted in a decrease in terpene and lactone content. These interactions are independent of biomass production. The aromatic profiles of T. delbrueckii and S. cerevisiae in mono-culture and in co-culture are very close, and are biomass-dependent, reflecting a neutral interaction. This study reveals that a whole family of compounds could be altered by such interactions. These results suggest that the entire metabolic pathway is affected by these interactions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation of biomass production in unleaded gasoline and BTEX-fed batch reactors.

Science.gov (United States)

Acuna-Askar, K; Englande, A J; Ramirez-Medrano, A; Coronado-Guardiola, J E; Chavez-Gomez, B

2003-01-01

BTEX removal under aerobic conditions by unleaded gasoline acclimated biomass and BTEX acclimated biomass, and the effect of surfactant on BTEX biodegradation were evaluated. The effect of BTEX concentration as the sole source of carbon for biomass acclimation and the effect of yeast extract on cell growth in unleaded gasoline-fed reactors were also evaluated. For the unleaded gasoline acclimated biomass, benzene was shown the most recalcitrant among all BTEX, followed by o-xylene and toluene with 16-23%, 35-41% and 57-69% biodegradation, respectively. Ethylbenzene was consistently the fastest BTEX chemical removed with 99% biodegradation for the four bioreactor acclimated biomasses tested. For the 1,200 ppm BTEX acclimated biomass, benzene showed the highest removal efficiency (99%) among the four biomass environmental conditions tested, along with 99% toluene and 99% ethylbenzene biodegradation. O-xylene showed 92-94% removal. In all bioassays tested Tergitol NP-10 was fully removed, and did not have a substantial effect on BTEX biodegradation at the end of a 10-day evaluation.

Bioethanol production from starchy biomass by direct fermentation using saccharomyces diastaticus in batch free and immobilized cell systems

Energy Technology Data Exchange (ETDEWEB)

Kilonzo, P.M.; Margaritis, A. [University of Western Ontario, London, ON (Canada). Dept. of Chemical and Biochemical Engineering; Yu, J.; Ye, Q. [East China Univ. of Science and Technology, Shanghai (China). Biochemical Engineering Research Inst. and State Key Lab

2006-07-01

The feasibility of using amylolytic yeasts for the direct fermentation of starchy biomass to ethanol was discussed. Although amylolytic yeasts such as Saccharomycopsis, Lipomyces, and Schwaniomyces secrete both {alpha}-amylase and glucoamylase enzymes that synergistically enhance starch degradation, they are not suitable for industrial bio-ethanol production because of low tolerance for ethanol and slow fermentation rate. For that reason, this study examined the direct ethanol fermentation of soluble starch or dextrin with the amylolytic yeast Saccharomyces diastaticus in batch free and immobilized cells systems. Saccharomyces diastaticus secretes glucoamylase and can therefore assimilate and ferment starch and starch-like biomass. The main focus of the study was on parameters leading to higher ethanol yields from high concentration of dextrin and soluble starch using batch cultures. A natural attachment method was proposed in which polyurethane foam sheets were used as the carrier for amylolytic yeasts immobilization in ethanol fermentations. The support was chosen because it was inexpensive, autoclavable, pliable and could be tailored to suit process requirements regarding net surface charge, shape and size. It was found that Saccharomyces diastaticus was very efficient in terms of fermentation of high initial concentrations of dextrin or soluble starch. Higher concentrations of ethanol were produced. In batch fermentations, the cells fermented high dextrin concentrations more efficiently. In particular, in batch fermentation, more than 92 g-L of ethanol was produced from 240 g-L of dextrin, at conversion efficiency of 90 per cent. The conversion efficiency decreased to 60 per cent but a higher final ethanol concentration of 147 g/L was attained with a medium containing 500 g/L of dextrin. In an immobilized cell bioreactor, Saccharomyces diastaticus produced 83 g/L of ethanol from 240 g/L of dextrin, corresponding to ethanol volumetric productivity of 9.1 g

Enhanced α-ketoglutaric acid production and recovery in Yarrowia lipolytica yeast by effective pH controlling.

Science.gov (United States)

Morgunov, Igor G; Kamzolova, Svetlana V; Samoilenko, Vladimir A

2013-10-01

The replacement of chemical synthesis by environmentally friendly energy-efficient technologies for production of valuable metabolites is a principal strategy of developing biotechnological industry all over the world. In the present study, we develop a method for α-ketoglutaric acid (KGA) production from rapeseed oil with the use of Yarrowia lipolytica yeast. Sixty strains of Y. lipolytica yeasts were tested for their ability to produce KGA, and the strain Y. lipolytica 212 (Y. lipolytica VKM Y-2412) was selected as a promising KGA producer. Using a three-stage pH controlling, in which pH was 4.5 in the growth phase, then since 72 to 144 h, pH was maintained at 3.5 and in the later phase of acid production, the titration by KOH was switch off, selected strain produced 106.5 g l(-1) of KGA with mass yield of 0.95 g g(-1). KGA in the form of monopotassium salt was isolated from the culture broth and purified. The isolation procedure involved separation of biomass, extraction of residual triglycerides, filtrate bleaching, and acidification with mineral acid (to pH 2.8-3.4), concentration, precipitation of mineral salts, and crystallization of the product. The purity of KGA isolated from the culture filtrate reached 99.1 %.

Growth conditions for the biomass yield of two methanol utilizing yeast spp. , Candida sp. and Rhodotorula sp

Energy Technology Data Exchange (ETDEWEB)

Hong, S.W.

1976-01-01

More than 580 MeOH utilizing yeasts were isolated from samples collected throughout South Korea. Of these, 2 strains showed good biomass yield and were selected and tentatively identified as Candida melinii and Rhodotorula glutinis glutinis. Experiments on growth conditions for these 2 species were performed. Optimum pH was 2.6 for Candida, 5.2 for Rhodotorula, and the temperature optimum was 28 to 30/sup 0/ for both. Maximum biomass yield was 4.32 g/L for Candida and 4.2l g/L for Rhodotorula. Optimum concentrations were (NH/sub 4/)/sub 2/SO/sub 4/ 0.3%, Mg/sup +/ 400 ppM, Fe/sup +/ 10 to 15 ppM for Candida and (NH/sub 4/)/sub 2/SO/sub 4/ 0.3% Mg/sup +/ 600 ppM Ca/sup +/ 2 ppM for Rhodotorula. Biotin stimulated Candida. Protein contents of the dry cell biomass were 39.3% in Candida and 44.0% in Rhodotorula.

Strategies for Optimizing Algal Biology for Enhanced Biomass Production

International Nuclear Information System (INIS)

Barry, Amanda N.; Starkenburg, Shawn R.; Sayre, Richard T.

2015-01-01

One of the most environmentally sustainable ways to produce high-energy density (oils) feed stocks for the production of liquid transportation fuels is from biomass. Photosynthetic carbon capture combined with biomass combustion (point source) and subsequent carbon capture and sequestration has also been proposed in the intergovernmental panel on climate change report as one of the most effective and economical strategies to remediate atmospheric greenhouse gases. To maximize photosynthetic carbon capture efficiency and energy-return-on-investment, we must develop biomass production systems that achieve the greatest yields with the lowest inputs. Numerous studies have demonstrated that microalgae have among the greatest potentials for biomass production. This is in part due to the fact that all alga cells are photoautotrophic, they have active carbon concentrating mechanisms to increase photosynthetic productivity, and all the biomass is harvestable unlike plants. All photosynthetic organisms, however, convert only a fraction of the solar energy they capture into chemical energy (reduced carbon or biomass). To increase aerial carbon capture rates and biomass productivity, it will be necessary to identify the most robust algal strains and increase their biomass production efficiency often by genetic manipulation. We review recent large-scale efforts to identify the best biomass producing strains and metabolic engineering strategies to improve aerial productivity. These strategies include optimization of photosynthetic light-harvesting antenna size to increase energy capture and conversion efficiency and the potential development of advanced molecular breeding techniques. To date, these strategies have resulted in up to twofold increases in biomass productivity.

Strategies for Optimizing Algal Biology for Enhanced Biomass Production

Energy Technology Data Exchange (ETDEWEB)

Barry, Amanda N.; Starkenburg, Shawn R.; Sayre, Richard T., E-mail: rsayre@newmexicoconsortium.org [Los Alamos National Laboratory, New Mexico Consortium, Los Alamos, NM (United States)

2015-02-02

One of the most environmentally sustainable ways to produce high-energy density (oils) feed stocks for the production of liquid transportation fuels is from biomass. Photosynthetic carbon capture combined with biomass combustion (point source) and subsequent carbon capture and sequestration has also been proposed in the intergovernmental panel on climate change report as one of the most effective and economical strategies to remediate atmospheric greenhouse gases. To maximize photosynthetic carbon capture efficiency and energy-return-on-investment, we must develop biomass production systems that achieve the greatest yields with the lowest inputs. Numerous studies have demonstrated that microalgae have among the greatest potentials for biomass production. This is in part due to the fact that all alga cells are photoautotrophic, they have active carbon concentrating mechanisms to increase photosynthetic productivity, and all the biomass is harvestable unlike plants. All photosynthetic organisms, however, convert only a fraction of the solar energy they capture into chemical energy (reduced carbon or biomass). To increase aerial carbon capture rates and biomass productivity, it will be necessary to identify the most robust algal strains and increase their biomass production efficiency often by genetic manipulation. We review recent large-scale efforts to identify the best biomass producing strains and metabolic engineering strategies to improve aerial productivity. These strategies include optimization of photosynthetic light-harvesting antenna size to increase energy capture and conversion efficiency and the potential development of advanced molecular breeding techniques. To date, these strategies have resulted in up to twofold increases in biomass productivity.

Removal of remazol brilliant blue R dye from aqueous solutions using yeast biomass as biosorbent

International Nuclear Information System (INIS)

Barreda-Reyes, Karen L.; Ortega-López, Jocelyn; Ortega-Regules, Ana E.; Santiago-Santiago, Luis A.; Netzahuatl-Muñoz, Alma R.

2015-01-01

The main purpose of this study was to obtain kinetic and equilibrium parameters for the anthraquinone dye r emoval of Remazol Brilliant Blue R dye from aqueous solutions using yeast biomass as biosorbent, and identify the functional groups responsible for biosorption by infrared spectrometry. Biosorption dye kinetics at temperatures of 10 °C, 20 °C, 30 °C and 40 °C were fitted correctly by the pseudo-first and pseudo-second order models. The values of thermodynamic activation parameters indicated that the biosorption process is endothermic and no spontaneous. Sorption isotherm at 20 °C, pH 2,0 and a biomass concentration of 1,0 g L-1 was obtained, finding a value of 127,6 mg g-1 for the saturated monolayer according to the Langmuir model. Infrared studies showed that carboxyl and amide are the main functional groups responsible for dye biosorption. (author)

Economic feasibility of invesment alternatives for reducing torula yeast' production cost

International Nuclear Information System (INIS)

Torres Fernández, Alfredo; Díaz de los Ríos, Manuel; Saura Laria, Gustavo

2016-01-01

The prices of ammonium salts which are used in the torula yeast production technology are very high nowadays. In the other hand, this technology has very high energy costs which are consumed by blowers in fermentation, separators machines and in the concentration and drying of yeast. In this paper, different technical alternatives are analyzed for reducing the production cost of torula yeast, through changes in production inputs, electric motors and the replacement of a portion of the fuel used for drying by biogas. Then, the economic feasibility in both currencies is evaluated for practical application. (author)

ECONOMIC FEASIBILITY OF INVESMENT ALTERNATIVES FOR REDUCING TORULA YEAST' PRODUCTION COST

Directory of Open Access Journals (Sweden)

Alfredo Torres Fernández

2016-01-01

Full Text Available The prices of ammonium salts which are used in the torula yeast production technology are very high nowadays. In the other hand, this technology has very high energy costs which are consumed by blowers in fermentation, separators machines and in the concentration and drying of yeast. In this paper, different technical alternatives are analyzed for reducing the production cost of torula yeast, through changes in production inputs, electric motors and the replacement of a portion of the fuel used for drying by biogas. Then, the economic feasibility in both currencies is evaluated for practical application.

Electricity production by advanced biomass power systems

Energy Technology Data Exchange (ETDEWEB)

Solantausta, Y [VTT Energy, Espoo (Finland). Energy Production Technologies; Bridgwater, T [Aston Univ. Birmingham (United Kingdom); Beckman, D [Zeton Inc., Burlington, Ontario (Canada)

1996-11-01

This report gives the results of the Pyrolysis Collaborative Project organized by the International Energy Agency (IEA) under Biomass Agreement. The participating countries or organizations were Canada, European Community (EC), Finland, United States of America, and the United Kingdom. The overall objective of the project was to establish baseline assessments for the performance and economics of power production from biomass. Information concerning the performance of biomass-fuelled power plants based on gasification is rather limited, and even less data is available of on pyrolysis based power applications. In order to gain further insight into the potential for these technologies, this study undertook the following tasks: (1) Prepare process models to evaluate the cost and performance of new advanced biomass power production concepts, (2) Assess the technical and economic uncertainties of different biomass power concepts, (3) Compare the concepts in small scale and in medium scale production (5 - 50 MW{sub e}) to conventional alternatives. Processes considered for this assessment were biomass power production technologies based on gasification and pyrolysis. Direct combustion technologies were employed as a reference for comparison to the processes assessed in this study. Wood was used a feedstock, since the most data was available for wood conversion

[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.

Thermodynamic evaluation of biomass-to-biofuels production systems

International Nuclear Information System (INIS)

Piekarczyk, Wodzisław; Czarnowska, Lucyna; Ptasiński, Krzysztof; Stanek, Wojciech

2013-01-01

Biomass is a renewable feedstock for producing modern energy carriers. However, the usage of biomass is accompanied by possible drawbacks, mainly due to limitation of land and water, and competition with food production. In this paper, the analysis concerns so-called second generation biofuels, like Fischer–Tropsch fuels or Substitute Natural Gas which are produced either from wood or from waste biomass. For these biofuels the most promising conversion case is the one which involves production of syngas from biomass gasification, followed by synthesis of biofuels. The thermodynamic efficiency of biofuels production is analyzed and compared using both the direct exergy analysis and the thermo-ecological cost. This analysis leads to the detection of exergy losses in various elements which forms the starting point to the improvement of conversion efficiency. The efficiency of biomass conversion to biofuels is also evaluated for the whole production chain, including biomass cultivation, transportation and conversion. The global effects of natural resources management are investigated using the thermo-ecological cost. The energy carriers' utilities such as electricity and heat are externally generated either from fossil fuels or from renewable biomass. In the former case the production of biofuels not always can be considered as a renewable energy source whereas in the latter case the production of biofuels leads always to the reduction of depletion of non-renewable resources

Study on the IAA (Indole acetic acid) Productivity of Soil Yeast Strain Isolats

International Nuclear Information System (INIS)

Nwe Nwe Soe Hlaing; Swe Zin Yu; San San Yu

2011-12-01

Twelve isolated soil yeast were tested in IAA production in peptone yeast glucose broth (PYG). All strains were screened for the Indole Acetic Acid (IAA) producing activity in PYG broth supplemented with or without L-Tryptophan (L-TRP) as precusor. IAA production was assayed calorimetrically using Salkowski's reagent. The concentration of IAA produced by yeast strains was measured by spectrophotometric method at 530nm. Y6 strain was the highest IAA producer (79ppm) at 9 days incubation period without tryptophan. Y3, Y10 and Y12 strains that were incubated without L-TRP also had the higher ability in the production of IAA than other yeast isolates. The selected yeasts having high IAA production activity were characterized by morphological study and biochemical tests including sugar assimilation and fermentation tests.

Continuous primary fermentation of beer with yeast immobilized on spent grains : the effect of operational conditions

OpenAIRE

Brányik, Tomáš; Vicente, A. A.; Cruz, José Machado; Teixeira, J. A.

2004-01-01

A one-stage continuous primary beer fermentation with immobilized brewing yeast was studied. The objective of the work was to optimize the operational conditions (aeration and temperature) in terms of volumetric productivity and organoleptic quality of green beer. The system consisted of an internal-loop airlift reactor and a carrier material prepared from spent grains (a brewing by-product). An industrial wort and yeast strain were used. The immobilized biomass (in amounts from two to sevenf...

PREPARATION OF ZINC ENRICHED YEAST (SACCHAROMYCES CEREVISIAE BY CULTIVATION WITH DIFFERENT ZINC SALTS

Directory of Open Access Journals (Sweden)

Ľuboš Harangozo

2012-02-01

Full Text Available The yeast Saccharomyces cerevisiae is the best known microorganism and therefore widely used in many branches of industry. This study aims to investigate the accumulation of three inorganic zinc salts. Our research presents the ability of this yeast to absorb zinc from liquid medium and such enriched biomass use as a potential source of microelements in animal and/or human nutrition. It was found that the addition of different zinc forms, i.e. zinc nitrate, zinc sulphate and zinc chloride in fixed concentrations of 0, 25, 50 and 100 mg.100 ml-1 did not affect the amount of dry yeast biomass yielded, i.e. 1.0 – 1.2 g of yeast cells from 100 ml of cultivation medium, while higher presence of zinc solutions caused significantly lower yield of yeast biomass. The highest amount of zinc in yeast cells was achieved when added in the form of zinc nitrate in concentration of 200 mg.100 ml-1 YPD medium. The increment of intracellular zinc was up to 18.5 mg.g-1 of yeast biomass.

Stable current outputs and phytate degradation by yeast-based biofuel cell.

Science.gov (United States)

Hubenova, Yolina; Georgiev, Danail; Mitov, Mario

2014-09-01

In this paper, we report for the first time that Candida melibiosica 2491 yeast strain expresses enhanced phytase activity when used as a biocatalyst in biofuel cells. The polarization also results in an increase of the yeast biomass. Higher steady-state electrical outputs, assigned to earlier production of an endogenous mediator, were achieved at continuous polarization under constant load. The obtained results prove that the C. melibiosica yeast-based biofuel cell could be used for simultaneous electricity generation and phytate bioremediation. In addition, the higher phytase activity obtained by interruptive polarization suggests a new method for increasing the phytase yield from microorganisms. Copyright © 2014 John Wiley & Sons, Ltd.

Biomass production efficiency controlled by management in temperate and boreal ecosystems

Science.gov (United States)

Campioli, M.; Vicca, S.; Luyssaert, S.; Bilcke, J.; Ceschia, E.; Chapin, F. S., III; Ciais, P.; Fernández-Martínez, M.; Malhi, Y.; Obersteiner, M.; Olefeldt, D.; Papale, D.; Piao, S. L.; Peñuelas, J.; Sullivan, P. F.; Wang, X.; Zenone, T.; Janssens, I. A.

2015-11-01

Plants acquire carbon through photosynthesis to sustain biomass production, autotrophic respiration and production of non-structural compounds for multiple purposes. The fraction of photosynthetic production used for biomass production, the biomass production efficiency, is a key determinant of the conversion of solar energy to biomass. In forest ecosystems, biomass production efficiency was suggested to be related to site fertility. Here we present a database of biomass production efficiency from 131 sites compiled from individual studies using harvest, biometric, eddy covariance, or process-based model estimates of production. The database is global, but dominated by data from Europe and North America. We show that instead of site fertility, ecosystem management is the key factor that controls biomass production efficiency in terrestrial ecosystems. In addition, in natural forests, grasslands, tundra, boreal peatlands and marshes, biomass production efficiency is independent of vegetation, environmental and climatic drivers. This similarity of biomass production efficiency across natural ecosystem types suggests that the ratio of biomass production to gross primary productivity is constant across natural ecosystems. We suggest that plant adaptation results in similar growth efficiency in high- and low-fertility natural systems, but that nutrient influxes under managed conditions favour a shift to carbon investment from the belowground flux of non-structural compounds to aboveground biomass.

Performance evaluation of startup for a yeast membrane bioreactor (MBRy) treating landfill leachate.

Science.gov (United States)

Amaral, Míriam C S; Gomes, Rosimeire F; Brasil, Yara L; Oliveira, Sílvia M A; Moravia, Wagner G

2017-12-06

The startup process of a membrane bioreactor inoculated with yeast biomass (Saccharomyces cerevisiae) and used in the treatment of landfill leachate was evaluated. The yeast membrane bioreactor (MBRy) was inoculated with an exogenous inoculum, a granulated active dry commercial bakers' yeast. The MBRy was successfully started up with a progressive increase in the landfill leachate percentage in the MBRy feed and the use of Sabouraud Dextrose Broth. The membrane plays an important role in the startup phase because of its full biomass retention and removal of organic matter. MBRy is a suitable and promising process to treat recalcitrant landfill leachate. After the acclimation period, the COD and NH 3 removal efficiency reached values of 72 ± 3% and 39 ± 2% respectively. MBRy shows a low membrane-fouling potential. The membrane fouling was influenced by soluble microbial products, extracellular polymeric substances, sludge particle size, and colloidal dissolved organic carbon.

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

Science.gov (United States)

Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

2015-01-01

Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

LIVE/DEAD YEAST VIABILITY STAINING AS A TOOL FOR IMPROVING ARTISANAL PILSNER BEER PRODUCTION

Directory of Open Access Journals (Sweden)

Benedetta Bottari

2014-10-01

Full Text Available The production of an artisanal beer, made by brewers using traditional practices on a small scale, is founded on the empirical adjustment of parameters, including yeasts handling and serial repitching. The aim of this study was to monitor yeast viability during different stages of artisanal beer productions through the Live/Dead Yeast viability staining and to correlate it with fermentation dynamics in order to increase process standardization and to maintain the quality of final products. Yeast viability and fermentation activities were evaluated during seven fermentation cycles of an artisanal pilsner beer. Yeast inoculated with higher viability performed generally better in fermentation, resulting in faster sugar consumption, faster ethanol production and stability. Handling yeast and serial repitching based on Live/Dead viability measurements, could be the key way to ensure reliable manufacture of high quality beer and to improve process standardization particularly for microbreweries, where variability of production can be a challenging point.

Growth and biomass production with enhanced {beta}-glucan and dietary fibre contents of Ganoderma australe ATHUM 4345 in a batch-stirred tank bioreactor

Energy Technology Data Exchange (ETDEWEB)

Papaspyridi, Lefki-Maria; Christakopoulos, Paul [BIOtechMASS Unit, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens (Greece); Katapodis, Petros [BIOtechMASS Unit, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens (Greece); Biotechnology Laboratory, Department of Biological Applications and Technologies, University of Ioannina, Ioannina (Greece); Gonou-Zagou, Zacharoula; Kapsanaki-Gotsi, Evangelia [Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, Athens (Greece)

2011-02-15

In this study we maximized biomass production by the basidiomycete Ganoderma australe ATHUM 4345, a species of pharmaceutical interest as it is a valuable source of nutraceuticals, including dietary fibers and glucans. We used the Biolog FF MicroPlate to screen 95 different carbon sources for growth monitoring. The pattern of substrate catabolism forms a substrate assimilation fingerprint, which is useful in selecting components for media optimization of maximum biomass production. Response surface methodology, based on the central composite design was applied to explore the optimum concentrations of carbon and nitrogen sources of culture medium in shake flask cultures. When the improved culture medium was tested in a 20-L stirred tank bioreactor, using 13.7 g/L glucose and 30.0 g/L yeast extract, high biomass yields (10.1{+-}0.4 g/L) and productivity of 0.09 g L{sup -1} h{sup -1} were obtained. The yield coefficients for total glucan and dietary fibers on biomass formed were 94.82{+-}6 and 341.15{+-}12.3 mg/g mycelium dry weight, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Use Of Local Product Yeast For Substitution Torula Yeast In The Formulation Of Artificial Diet Fruit Fly Larvae Bactrocera Carambolae Drew and Hancock

International Nuclear Information System (INIS)

Sikumbang, I.; Nasution, A.I.; Indarwatmi, M.; Kuswandi, A.N.

2000-01-01

The use of local product yeast I.e brewer yeast, yeast of tapai (fermented cassava), yeast of tempe (fermented soy beam), and brem(intoxicating beverage made of fermented rice) after cooked and uncooked were used to substitute torula yeast to reduce cost production for mass-rearing of fruit fly had been carried out. Artificial diet formulation consisted of torula yeast, wheat bran, nipagin, sodium benzoate, cane sugar, water and HCI ti make pH of 4. One kilogram of diet was inoculated with 1 ml of fruit fly eggs. Parameters of the experiment were, the number of pupae, weight of pupae, percentage of pupae and the percentage of viable fly. The results showed that the number of pupae were 6356 for brewers yeast with cooked and 0.942 gram/100 pupae for brem. Percentage viable emergence fly were 70%, 18.25% and 15.25% for brewers yeast with cooked and uncooked respectively. Cost production for 1.000.000 using cooked brewer yeast was reduced about Rp.179,200 or cost efficiency were 55.56%

Thermodynamic analysis of hydrogen production from biomass gasification

International Nuclear Information System (INIS)

Cohce, M.K.; Dincer, I.; Rosen, M.A.

2009-01-01

'Full Text': Biomass resources have the advantage of being renewable and can therefore contribute to renewable hydrogen production. In this study, an overview is presented of hydrogen production methods in general, and biomass-based hydrogen production in particular. For two methods in the latter category (direct gasification and pyrolysis), assessments are carried out, with the aim of investigating the feasibility of producing hydrogen from biomass and better understanding the potential of biomass as a renewable energy source. A simplified model is presented here for biomass gasification based on chemical equilibrium considerations, and the effects of temperature, pressure and the Gibbs free energy on the equilibrium hydrogen yield are studied. Palm oil (designated C 6 H 10 O 5 ), one of the most common biomass resources in the world, is considered in the analyses. The gasifier is observed to be one of the most critical components of a biomass gasification system, and is modeled using stoichiometric reactions. Various thermodynamic efficiencies are evaluated, and both methods are observed to have reasonably high efficiencies. (author)

Yeast synthetic biology for high-value metabolites.

Science.gov (United States)

Dai, Zhubo; Liu, Yi; Guo, Juan; Huang, Luqi; Zhang, Xueli

2015-02-01

Traditionally, high-value metabolites have been produced through direct extraction from natural biological sources which are inefficient, given the low abundance of these compounds. On the other hand, these high-value metabolites are usually difficult to be synthesized chemically, due to their complex structures. In the last few years, the discovery of genes involved in the synthetic pathways of these metabolites, combined with advances in synthetic biology tools, has allowed the construction of increasing numbers of yeast cell factories for production of these metabolites from renewable biomass. This review summarizes recent advances in synthetic biology in terms of the use of yeasts as microbial hosts for the identification of the pathways involved in the synthesis, as well as for the production of high-value metabolites. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Environmental assessment of different strategies for production of stabilized yeast

OpenAIRE

Monclus, Vincent; Pénicaud, Caroline; Perret, Bruno; Fonseca, Fernanda

2016-01-01

Yeast are widely used for producing fermented (bread, beer...) and health benefit (probiotics) products. The production of stable and active yeast involves fermentation, concentration, protection, drying (stabilization) and storage. During the stabilization and storage steps, the cells face numerous stress which may deteriorate functional properties and cause cell death. Different strategies can be used to preserve cell survival, such as changing growth medium for fermentation or adapting pro...

Sustainable Biomass Resources for Biogas Production

DEFF Research Database (Denmark)

Meyer, Ane Katharina Paarup

The aim of this thesis was to identify and map sustainable biomass resources, which can be utilised for biogas production with minimal negative impacts on the environment, nature and climate. Furthermore, the aim of this thesis was to assess the resource potential and feasibility of utilising...... such biomasses in the biogas sector. Sustainability in the use of biomass feedstock for energy production is of key importance for a stable future food and energy supply, and for the functionality of the Earths ecosystems. A range of biomass resources were assessed in respect to sustainability, availability...... from 39.3-66.9 Mtoe, depending on the availability of the residues. Grass from roadside verges and meadow habitats in Denmark represent two currently unutilised sources. If utilised in the Danish biogas sector, the results showed that the resources represent a net energy potential of 60,000 -122,000 GJ...

Advances in metabolic engineering of yeast Saccharomyces cerevisiae for production of chemicals

DEFF Research Database (Denmark)

Borodina, Irina; Nielsen, Jens

2014-01-01

Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up the deve......Yeast Saccharomyces cerevisiae is an important industrial host for production of enzymes, pharmaceutical and nutraceutical ingredients and recently also commodity chemicals and biofuels. Here, we review the advances in modeling and synthetic biology tools and how these tools can speed up...... the development of yeast cell factories. We also present an overview of metabolic engineering strategies for developing yeast strains for production of polymer monomers: lactic, succinic, and cis,cis-muconic acids. S. cerevisiae has already firmly established itself as a cell factory in industrial biotechnology...

Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

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Elham Aslankoohi

Full Text Available Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

Produção de biossurfactante por levedura Biosurfactants production by yeasts

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Gizele Cardoso Fontes

2008-01-01

Full Text Available Biosurfactants are molecules extracellularly produced by bacteria, yeast and fungi that have significant interfacial activity properties. This review focuses on relevant parameters that influence biosurfactant production by yeasts. Many works have investigated the optimization of yeast biosurfactant production, mainly within the last decade, revealing that the potential of such microorganisms is not well explored in the industrial field. The main points to increase the process viability lays on the reduction of the production costs and enhancement of biosynthesis efficiency through optimization the culture conditions (carbon and nitrogen source, pH, aeration, speed agitation and the selection of inexpensive medium components.

Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

Science.gov (United States)

Bywaters, Kathryn F.; Fritsen, Christian H.

2015-01-01

Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems – in addition to oil-derived fuels (Bird et al., 2011, 2012). Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass, and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 39.0 to 344.1 mg C L−1 day−1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production) ranged from 0 to 38.74 mg free fatty acids (FFA) and triacylglycerols (TAG) L−1 day−1; the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio) decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment. All results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels. PMID:25763368

Biomass and Neutral Lipid Production in Geothermal Microalgal Consortia

Directory of Open Access Journals (Sweden)

Kathryn Faye Bywaters

2015-02-01

Full Text Available Recently, technologies have been developed that offer the possibility of using algal biomass as feedstocks to energy producing systems- in addition to oil-derived fuels (Bird et al., 2011;Bird et al., 2012. Growing native mixed microalgal consortia for biomass in association with geothermal resources has the potential to mitigate negative impacts of seasonally low temperatures on biomass production systems as well as mitigate some of the challenges associated with growing unialgal strains. We assessed community composition, growth rates, biomass and neutral lipid production of microalgal consortia obtained from geothermal hot springs in the Great Basin/Nevada area that were cultured under different thermal and light conditions. Biomass production rates ranged from 368 to 3246 mg C L-1 d-1. The neutral lipid production in these consortia with and without shifts to lower temperatures and additions of bicarbonate (both environmental parameters that have been shown to enhance neutral lipid production ranged from zero to 38.74 mg free fatty acids and triacylglycerols L-1 d-1, the upper value was approximately 6% of the biomass produced. The higher lipid values were most likely due to the presence of Achnanthidium sp. Palmitic and stearic acids were the dominant free fatty acids. The S/U ratio (the saturated to unsaturated FA ratio decreased for cultures shifted from their original temperature to 15°C. Biomass production was within the upper limits of those reported for individual strains, and production of neutral lipids was increased with secondary treatment – all results demonstrate a potential of culturing and manipulating resultant microalgal consortia for biomass-based energy production and perhaps even for biofuels.

Biomass gasification for production of 'green energy'

International Nuclear Information System (INIS)

Mambre, V.

2008-01-01

This paper presents the differences between biomass gasification and biomass methanation, two ways of using biomass for decentralized production of energy. The stakes of biomass and biomass gasification for meeting the European and national energy goals and environmental targets are summarized. The gasification principle is described and in particular the FICFB optimized process from Repotec for the production of concentrated syngas. The four different ways of syngas valorization (combined heat and power (CHP), 'green methane' (SNG), 'green hydrogen' (gas shift) and liquid biofuels of 2. generation (Fisher-Tropsch)) are recalled and compared with each other. Finally, the economical and environmental key issues of the global chain are summarized with their technological and scientific key locks. The GAYA R and D project of Gaz de France Suez group, which aims at developing gasification and methanation demonstration plants through different programs with European partners, is briefly presented. (J.S.)

Relationships between biomass composition and liquid products formed via pyrolysis

Directory of Open Access Journals (Sweden)

Fan eLin

2015-10-01

Full Text Available Thermal conversion of biomass is a rapid, low-cost way to produce a dense liquid product, known as bio-oil, that can be refined to transportation fuels. However, utilization of bio-oil is challenging due to its chemical complexity, acidity, and instability—all results of the intricate nature of biomass. A clear understanding of how biomass properties impact yield and composition of thermal products will provide guidance to optimize both biomass and conditions for thermal conversion. To aid elucidation of these associations, we first describe biomass polymers, including phenolics, polysaccharides, acetyl groups, and inorganic ions, and the chemical interactions among them. We then discuss evidence for three roles (i.e., models for biomass components in formation of liquid pyrolysis products: (1 as direct sources, (2 as catalysts, and (3 as indirect factors whereby chemical interactions among components and/or cell wall structural features impact thermal conversion products. We highlight associations that might be utilized to optimize biomass content prior to pyrolysis, though a more detailed characterization is required to understand indirect effects. In combination with high-throughput biomass characterization techniques this knowledge will enable identification of biomass particularly suited for biofuel production and can also guide genetic engineering of bioenergy crops to improve biomass features.

Relationships between Biomass Composition and Liquid Products Formed via Pyrolysis

International Nuclear Information System (INIS)

Lin, Fan; Waters, Christopher L.; Mallinson, Richard G.; Lobban, Lance L.; Bartley, Laura E.

2015-01-01

Thermal conversion of biomass is a rapid, low-cost way to produce a dense liquid product, known as bio-oil, that can be refined to transportation fuels. However, utilization of bio-oil is challenging due to its chemical complexity, acidity, and instability – all results of the intricate nature of biomass. A clear understanding of how biomass properties impact yield and composition of thermal products will provide guidance to optimize both biomass and conditions for thermal conversion. To aid elucidation of these associations, we first describe biomass polymers, including phenolics, polysaccharides, acetyl groups, and inorganic ions, and the chemical interactions among them. We then discuss evidence for three roles (i.e., models) for biomass components in the formation of liquid pyrolysis products: (1) as direct sources, (2) as catalysts, and (3) as indirect factors whereby chemical interactions among components and/or cell wall structural features impact thermal conversion products. We highlight associations that might be utilized to optimize biomass content prior to pyrolysis, though a more detailed characterization is required to understand indirect effects. In combination with high-throughput biomass characterization techniques, this knowledge will enable identification of biomass particularly suited for biofuel production and can also guide genetic engineering of bioenergy crops to improve biomass features.

Immobilised Sarawak Malaysia yeast cells for production of bioethanol.

Science.gov (United States)

Zain, Masniroszaime Mohd; Kofli, Noorhisham Tan; Rozaimah, Siti; Abdullah, Sheikh

2011-05-01

Bioethanol production using yeast has become a popular topic due to worrying depleting worldwide fuel reserve. The aim of the study was to investigate the capability of Malaysia yeast strains isolated from starter culture used in traditional fermented food and alcoholic beverages in producing Bioethanol using alginate beads entrapment method. The starter yeast consists of groups of microbes, thus the yeasts were grown in Sabouraud agar to obtain single colony called ST1 (tuak) and ST3 (tapai). The growth in Yeast Potatoes Dextrose (YPD) resulted in specific growth of ST1 at micro = 0.396 h-1 and ST3 at micro = 0.38 h-1, with maximum ethanol production of 7.36 g L-1 observed using ST1 strain. The two strains were then immobilized using calcium alginate entrapment method producing average alginate beads size of 0.51 cm and were grown in different substrates; YPD medium and Local Brown Sugar (LBS) for 8 h in flask. The maximum ethanol concentration measured after 7 h were at 6.63 and 6.59 g L-1 in YPD media and 1.54 and 1.39 g L-1in LBS media for ST1 and ST3, respectively. The use of LBS as carbon source showed higher yield of product (Yp/s), 0.59 g g-1 compared to YPD, 0.25 g g-1 in ST1 and (Yp/s), 0.54 g g-1 compared to YPD, 0.24 g g-1 in ST3 . This study indicated the possibility of using local strains (STI and ST3) to produce bioethanol via immobilization technique with local materials as substrate.

Biomass production efficiency controlled by management in temperate and boreal ecosystems

NARCIS (Netherlands)

Campioli, M.; Vicca, S.; Luyssaert, S.; Bilcke, J.; Ceschia, E.; Chapin, F.S. III; Ciais, P.; Fernández-Martínez, M.; Malhi, Y.; Obersteiner, M.; Olefeldt, D.; Papale, D.; Piao, S.L.; Peñuelas, J.; Sullivan, P. F.; Wang, X.; Zenone, T.; Janssens, I.A.

2015-01-01

Plants acquire carbon through photosynthesis to sustain biomass production, autotrophic respiration and production of non-structural compounds for multiple purposes. The fraction of photosynthetic production used for biomass production, the biomass production efficiency, is a key determinant of the

Method for producing ethanol and co-products from cellulosic biomass

Science.gov (United States)

Nguyen, Quang A

2013-10-01

The present invention generally relates to processes for production of ethanol from cellulosic biomass. The present invention also relates to production of various co-products of preparation of ethanol from cellulosic biomass. The present invention further relates to improvements in one or more aspects of preparation of ethanol from cellulosic biomass including, for example, improved methods for cleaning biomass feedstocks, improved acid impregnation, and improved steam treatment, or "steam explosion."

Yeast cell surface display: An efficient strategy for improvement of bioethanol fermentation performance.

Science.gov (United States)

Chen, Xianzhong

2017-03-04

The cell surface serves as a functional interface between the inside and the outside of the cell. Within the past 20 y the ability of yeast (Saccharomyces cerevisiae) to display heterologous proteins on the cell surface has been demonstrated. Furthermore, S. cerevisiae has been both developed and applied in expression of various proteins on the cell surface. Using this novel and useful strategy, proteins and peptides of various kinds can be displayed on the yeast cell surface by fusing the protein of interest with the glycosylphosphatidylinositol (GPI)-anchoring system. Consolidated bioprocessing (CBP) using S. cerevisiae represents a promising technology for bioethanol production. However, further work is needed to improve the fermentation performance. There is some excellent previous research regarding construction of yeast biocatalyst using the surface display system to decrease cost, increase efficiency of ethanol production and directly utilize starch or biomass for fuel production. In this commentary, we reviewed the yeast surface display system and highlighted recent work. Additionally, the strategy for decrease of phytate phosphate content in dried distillers grains with solubles (DDGS) by display of phytase on the yeast cell surface is discussed.

Spectrophotometric evaluation of selenium binding by Saccharomyces cerevisiae ATCC MYA-2200 and Candida utilis ATCC 9950 yeast.

Science.gov (United States)

Kieliszek, Marek; Błażejak, Stanisław; Płaczek, Maciej

2016-05-01

In this study, the ability of selenium binding the biomas of Saccharomyces cerevisiae ATCC MYA-2200 and Candida utilis ATCC 9950 was investigated. Sodium selenite(IV) salts were added to the experimental media at concentrations of 10, 20, 40, and 60 mg Se(4+) L(-1). In the tested concentration range, one concentration reported a significant reduction in the biomass yield of both yeast strains. Intense growth was observed for C. utilis yeast, which reached the highest biomass yield of 15 gd.w.L(-1) after 24h cultivation in the presence of 10mg Se(4+) L(-1). Based on the use of spectrophotometric method for the determination of selenium content by using Variamine Blue as a chromogenic agent, efficient accumulation of this element in the biomass of the investigated yeast was observed. The highest amount of selenium, that is, 5.64 mg Se(4+)gd.w.(-1), was bound from the environment by S. cerevisiae ATCC MYA-2200 cultured in the presence of 60 mg Se(4+) L(-1) medium 72h Slightly less amount, 5.47 mg Se(4+) gd.w.(-1), was absorbed by C. utilis ATCC 9950 during similar cultural conditions. Based on the results of the biomass yield and the use of selenium from the medium, it can be observed that yeasts of the genus Candida are more efficient in binding this element, and this property finds practical application in the production of selenium-enriched yeast. Copyright © 2016 Elsevier GmbH. All rights reserved.

Production of baker's yeast using date juice.

Science.gov (United States)

Beiroti, A; Hosseini, S N

2007-07-01

Baker's yeast is an important additive among the products which improves bread quality and for present time is being produced in different countries by batch, fed batch or continuous cultures. Saccharomyces cerevisiae is used in fermentation of starch in dough, giving a favourable taste and produces a variety of vitamins and proteins. The main ingredient in yeast production is carbon source such as beet molasses, cane molasses, and so on. Since beet molasses has other major function as in high yield alcohol production and also due to the bioenvironmental issues and related wastewater treatment, the use of other carbohydrate sources may be considered. One of these carbohydrate sources is date which is wasted a great deal annually in this country (Iran) . In this study, the capability of date to act as a suitable carbon sources was investigated. The waste date turned into juice and consequently production and growth rate of Sacchromyces cervisiae were studied with this juice. A maximum possible yield of 50% was obtained by the optimum medium (P3), at pH 3.4, 30 degrees C, 1.4 vvm aeration rate and agitation of 500 r/min.

Biomass production potentials in Central and Eastern Europe under different scenarios

International Nuclear Information System (INIS)

Dam, J. van; Faaij, A.P.C.; Lewandowski, I.; Fischer, G.

2007-01-01

A methodology for the assessment of biomass potentials was developed and applied to Central and Eastern European countries (CEEC). Biomass resources considered are agricultural residues, forestry residues, and wood from surplus forest and biomass from energy crops. Only land that is not needed for food and feed production is considered as available for the production of energy crops. Five scenarios were built to depict the influences of different factors on biomass potentials and costs. Scenarios, with a domination of current level of agricultural production or ecological production systems, show the smallest biomass potentials of 2-5.7 EJ for all CEEC. Highest potentials can reach up to 11.7 EJ (85% from energy crops, 12% from residues and 3% from surplus forest wood) when 44 million ha of agricultural land become available for energy crop production. This potential is, however, only realizable under high input production systems and most advanced production technology, best allocation of crop production over all CEEC and by choosing willow as energy crops. The production of lignocellulosic crops, and willow in particular, best combines high biomass production potentials and low biomass production costs. Production costs for willow biomass range from 1.6 to 8.0 EUR/GJ HHV in the scenario with the highest agricultural productivity and 1.0-4.5 EUR/GJ HHV in the scenario reflecting the current status of agricultural production. Generally the highest biomass production costs are experienced when ecological agriculture is prevailing and on land with lower quality. In most CEEC, the production potentials are larger than the current energy use in the more favourable scenarios. Bulk of the biomass potential can be produced at costs lower than 2 EUR/GJ. High potentials combined with the low cost levels gives CEEC major export opportunities. (author)

Production of fermentation aroma compounds by Saccharomyces cerevisiae wine yeasts: effects of yeast assimilable nitrogen on two model strains.

Science.gov (United States)

Carrau, Francisco M; Medina, Karina; Farina, Laura; Boido, Eduardo; Henschke, Paul A; Dellacassa, Eduardo

2008-11-01

The contribution of yeast fermentation metabolites to the aromatic profile of wine is well documented; however, the biotechnological application of this knowledge, apart from strain selection, is still rather limited and often contradictory. Understanding and modeling the relationship between nutrient availability and the production of desirable aroma compounds by different strains must be one of the main objectives in the selection of industrial yeasts for the beverage and food industry. In order to overcome the variability in the composition of grape juices, we have used a chemically defined model medium for studying yeast physiological behavior and metabolite production in response to nitrogen supplementation so as to identify an appropriate yeast assimilable nitrogen level for strain differentiation. At low initial nitrogen concentrations, strain KU1 produced higher quantities of esters and fatty acids whereas M522 produced higher concentrations of isoacids, gamma-butyrolactone, higher alcohols and 3-methylthio-1-propanol. We propose that although strains KU1 and M522 have a similar nitrogen consumption profile, they represent useful models for the chemical characterization of wine strains in relation to wine quality. The differential production of aroma compounds by the two strains is discussed in relation to their capacity for nitrogen usage and their impact on winemaking. The results obtained here will help to develop targeted metabolic footprinting methods for the discrimination of industrial yeasts.

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.

Glycobiology in yeast: production of bio-ative biopolymers and small molecules

Energy Technology Data Exchange (ETDEWEB)

Scheller, Henrik [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2014-04-30

The accomplished goals of the CRADA were the establishment of a yeast strain capable of producing levels of vanillin suitable for commercial production and the identification of novel glycosyltransferases to construct the biosynthetic pathway of a gum Arabic-variant in yeast.

Production of liquid transport fuel from cellulose material (wood). III Laboratory preparation of wood sugars and fermentation to ethanol and yeast

Energy Technology Data Exchange (ETDEWEB)

Whitworth, D A; Harwood, V D

1977-10-25

A laboratory procedure is described for hydrolyzing cellulose material to sugars by the use of hot sulfuric acid. The procedure has been used routinely for assessing raw materials. Raw materials used were radiata pine (fresh wood and decayed thinnings), pine needles, sawdust from old dumps, newspaper, cardboard, beech wood, and coconut wood. The neutralized sugar-liquors produced, supplemented with fertilizer grade nutrients, were fermented with bakers' yeast and gave near optimal conversion of hexoses to ethanol and of pentoses to protein biomass. From 100 g radiata pine (wood: bark mix 85:15) 25 ml (20 g) of ethanol and 2 g yeast biomass were routinely produced, although fermentation rates were lower than with pure sugars. The results, however, clearly showed that, by a hot dilute sulfure acid hydrolysis followed by a yeast fermentation process, cellulose resources avaliable in New Zealand are suitable for conversion to ethanol. 5 table, 1 figure.

Yeast Extract Promotes Cell Growth and Induces Production of Polyvinyl Alcohol-Degrading Enzymes

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Min Li

2011-01-01

Full Text Available Polyvinyl alcohol-degrading enzymes (PVAases have a great potential in bio-desizing processes for its low environmental impact and low energy consumption. In this study, the effect of yeast extract on PVAases production was investigated. A strategy of four-point yeast extract addition was developed and applied to maximize cell growth and PVAases production. As a result, the maximum dry cell weight achieved was 1.48 g/L and the corresponding PVAases activity was 2.99 U/mL, which are 46.5% and 176.8% higher than the control, respectively. Applying this strategy in a 7 L fermentor increased PVAases activity to 3.41 U/mL. Three amino acids (glycine, serine, and tyrosine in yeast extract play a central role in the production of PVAases. These results suggest that the new strategy of four-point yeast extract addition could benefit PVAases production.

Catabolism of biomass-derived sugars in fungi and metabolic engineering as a tool for organic acid production

Energy Technology Data Exchange (ETDEWEB)

Koivistoinen, O.

2013-11-01

The use of metabolic engineering as a tool for production of biochemicals and biofuels requires profound understanding of cell metabolism. The pathways for the most abundant and most important hexoses have already been studied quite extensively but it is also important to get a more complete picture of sugar catabolism. In this thesis, catabolic pathways of L-rhamnose and D-galactose were studied in fungi. Both of these hexoses are present in plant biomass, such as in hemicellulose and pectin. Galactoglucomannan, a type of hemicellulose that is especially rich in softwood, is an abundant source of D-galactose. As biotechnology is moving from the usage of edible and easily metabolisable carbon sources towards the increased use of lignocellulosic biomass, it is important to understand how the different sugars can be efficiently turned into valuable biobased products. Identification of the first fungal L-rhamnose 1-dehydrogenase gene, which codes for the first enzyme of the fungal catabolic L-rhamnose pathway, showed that the protein belongs to a protein family of short-chain alcohol dehydrogenases. Sugar dehydrogenases oxidising a sugar to a sugar acid are not very common in fungi and thus the identification of the L-rhamnose dehydrogenase gene provides more understanding of oxidative sugar catabolism in eukaryotic microbes. Further studies characterising the L-rhamnose cluster in the yeast Scheffersomyces stipitis including the expression of the L-rhamnonate dehydratase in Saccharomyces cerevisiae finalised the biochemical characterisation of the enzymes acting on the pathway. In addition, more understanding of the regulation and evolution of the pathway was gained. D-Galactose catabolism was studied in the filamentous fungus Aspergillus niger. Two genes coding for the enzymes of the oxido-reductive pathway were identified. Galactitol dehydrogenase is the second enzyme of the pathway converting galactitol to L-xylo-3-hexulose. The galactitol dehydrogenase encoding

Biotechnological production of carotenoids by yeasts: an overview

Science.gov (United States)

2014-01-01

Nowadays, carotenoids are valuable molecules in different industries such as chemical, pharmaceutical, poultry, food and cosmetics. These pigments not only can act as vitamin A precursors, but also they have coloring and antioxidant properties, which have attracted the attention of the industries and researchers. The carotenoid production through chemical synthesis or extraction from plants is limited by low yields that results in high production costs. This leads to research of microbial production of carotenoids, as an alternative that has shown better yields than other aforementioned. In addition, the microbial production of carotenoids could be a better option about costs, looking for alternatives like the use of low-cost substrates as agro-industrials wastes. Yeasts have demonstrated to be carotenoid producer showing an important growing capacity in several agro-industrial wastes producing high levels of carotenoids. Agro-industrial wastes provide carbon and nitrogen source necessary, and others elements to carry out the microbial metabolism diminishing the production costs and avoiding pollution from these agro-industrial wastes to the environmental. Herein, we discuss the general and applied concepts regarding yeasts carotenoid production and the factors influencing carotenogenesis using agro-industrial wastes as low-cost substrates. PMID:24443802

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)

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.

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...

Selection of Willows (Salix sp. for Biomass Production

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Davorin Kajba

2014-12-01

Full Text Available Background and Purpose: Willows compared with other species are the most suitable for biomass production in short rotations because of their very abundant growth during the first years. Nowadays, in Croatia, a large number of selected and registered willow clones are available. The main objective of the research should be to find genotypes which, with minimum nutrients, will produce the maximum quantity of biomass. Material and Methods: Clonal test of the arborescent willows include the autochthonous White Willow (Salix alba, interracial hybrids of the autochthonous White Willow and the English ‘cricket’ Willow (S. alba var. calva, interspecies hybrids (S. matsudana × S. alba, as well as multispecies hybrids of willows. Average production of dry biomass (DM∙ha-1∙a-1 per hectare was estimated in regard to the clone, survival, spacing and the number of shoots per stump. Results: The highest biomass production as well as the best adaptedness and phenotypic stability on testing site was shown by clones (‘V 374’, ‘V 461’, ‘V 578’ from 15.2 - 25.0 t∙DM∙ha-1∙a-1 originated from backcross hybrid S. matsudana × (S. matsudana × S. alba and by one S. alba clone (‘V 95’, 23.1 - 25.7 t∙DM∙ha-1∙a-1. These clones are now at the stage of registration and these results indicate significant potential for further breeding aimed at biomass production in short rotations. Conclusions: Willow clones showed high biomass production on marginal sites and dry biomass could be considerably increased with the application of intensive silvicultural and agro technical measures. No nutrition or pest control measures were applied (a practice otherwise widely used in intensive cultivation system, while weed vegetation was regulated only at the earliest age.

Utilization of spent brewer’s yeast Saccharomyces cerevisiae for the production of yeast enzymatic hydrolysate

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M Bayarjargal

2014-09-01

Full Text Available Spent brewer’s yeast (Saccharomyces cerevisiae is a rich source of protein, vitamins and widely used as a raw material for production of food supplements. The autolysis and enzymatic treatment of spent brewer’s yeast using Pancreatin (2.5% and Flavourzyme (2.5% were performed at 45 °C and 50 °C, respectively. The autolysis and hydrolysis processes were evaluated by determining a soluble solids, soluble protein concentration and α-amino nitrogen content in a reaction mixture. The yield of pancreatic digest and α-amino nitrogen content was high in comparison with autolysis and Flavourzyme treatment. The total solids recovery in dry Yeast hydrolysate was about 50%, a protein and α-amino nitrogen content was 55.9 and 4.8%, respectively. These results show the possibility of utilizing the spent brewer’s yeast as hydrolysate using hydrolytic enzymes and use it as a food supplement after biological experiments.DOI: http://dx.doi.org/10.5564/mjc.v12i0.179 Mongolian Journal of Chemistry Vol.12 2011: 88-91

Sugar utilization patterns and respiro-fermentative metabolism in the baker's yeast Torulaspora delbrueckii.

Science.gov (United States)

Alves-Araújo, C; Pacheco, A; Almeida, M J; Spencer-Martins, I; Leão, C; Sousa, M J

2007-03-01

The highly osmo- and cryotolerant yeast species Torulaspora delbrueckii is an important case study among the non-Saccharomyces yeast species. The strain T. delbrueckii PYCC 5321, isolated from traditional corn and rye bread dough in northern Portugal, is considered particularly interesting for the baking industry. This paper reports the sugar utilization patterns of this strain, using media with glucose, maltose and sucrose, alone or in mixtures. Kinetics of growth, biomass and ethanol yields, fermentation and respiration rates, hydrolase activities and sugar uptake rates were used to infer the potential applied relevance of this yeast in comparison to a conventional baker's strain of Saccharomyces cerevisiae. The results showed that both maltase and maltose transport in T. delbrueckii were subject to glucose repression and maltose induction, whereas invertase was subject to glucose control but not dependent on sucrose induction. A comparative analysis of specific sugar consumption rates and transport capacities suggests that the transport step limits both glucose and maltose metabolism. Specific rates of CO(2) production and O(2) consumption showed a significantly higher contribution of respiration to the overall metabolism in T. delbrueckii than in S. cerevisiae. This was reflected in the biomass yields from batch cultures and could represent an asset for the large-scale production of the former species. This work contributes to a better understanding of the physiology of a non-conventional yeast species, with a view to the full exploitation of T. delbrueckii by the baking industry.

Activation of waste brewer's yeast Saccharomyces cerevisiae for bread production

Directory of Open Access Journals (Sweden)

Popov Stevan D.

2005-01-01

Full Text Available The waste brewer's yeast S. cerevisiae (activated and non-activated was compared with the commercial baker's yeast regarding the volume of developed gas in dough, volume and freshness stability of produced bread. The activation of waste brewer's yeast resulted in the increased volume of developed gas in dough by 100% compared to non-activated brewer's yeast, and the obtained bread is of more stable freshness compared to bread produced with baker's yeast. The activation of BY affects positively the quality of produced bread regarding bread volume. The volume of developed gas in dough prepared with the use of non-activated BY was not sufficient, therefore, it should not be used as fermentation agent, but only as an additive in bread production process for bread freshness preservation. Intense mixing of dough results in more compressible crumb 48 hrs after baking compared to high-speed mixing.

Large-Scale Selection and Breeding To Generate Industrial Yeasts with Superior Aroma Production

Science.gov (United States)

Steensels, Jan; Meersman, Esther; Snoek, Tim; Saels, Veerle

2014-01-01

The concentrations and relative ratios of various aroma compounds produced by fermenting yeast cells are essential for the sensory quality of many fermented foods, including beer, bread, wine, and sake. Since the production of these aroma-active compounds varies highly among different yeast strains, careful selection of variants with optimal aromatic profiles is of crucial importance for a high-quality end product. This study evaluates the production of different aroma-active compounds in 301 different Saccharomyces cerevisiae, Saccharomyces paradoxus, and Saccharomyces pastorianus yeast strains. Our results show that the production of key aroma compounds like isoamyl acetate and ethyl acetate varies by an order of magnitude between natural yeasts, with the concentrations of some compounds showing significant positive correlation, whereas others vary independently. Targeted hybridization of some of the best aroma-producing strains yielded 46 intraspecific hybrids, of which some show a distinct heterosis (hybrid vigor) effect and produce up to 45% more isoamyl acetate than the best parental strains while retaining their overall fermentation performance. Together, our results demonstrate the potential of large-scale outbreeding to obtain superior industrial yeasts that are directly applicable for commercial use. PMID:25192996

Dynamic Analysis of Bioethanol Production from Corn Stover and Immobilized Yeast

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Shuang-Qi Tian

2016-05-01

Full Text Available The use of low cost and abundant corn stover in yeast fermentation can reduce product costs. In this study, bioethanol was produced from a hydrolysate of corn stover using immobilized yeast. A kinetic model was established for the total reducing sugar consumption and the production of bioethanol. The parameter estimation for kinetic modeling considered the main process variables during bioethanol production from corn stover. Total reducing sugar concentrations decreased exponentially in the bioethanol fermentation for 6 h; consumption was more than 90%. To use kinetic modelling of yeast growth for bioethanol fermentation, the value of μmax reached 0.2891 h-1, and the matrix inhibition constant (KIS and production inhibition constant (KIP were 8.9154 g/dm3 and 0.00676 g/dm3, respectively. To use kinetic modelling of fermentation time on bioethanol, the maximum ratio of bioethanol production rate (qmax reached 1.427 g/g•L. However, KIS was 2.813 g/dm3, and KIP was 0.0149 g/dm3.

Synthetic yeast based cell factories for vanillin-glucoside production

DEFF Research Database (Denmark)

Strucko, Tomas

and controlled expression/overexpression of genes of interest. De novo biosynthetic pathway for vanillin-β-glucoside production was employed as a model system for several case studies in this project. In order to construct yeast cell factories fulfilling current demands of industrial biotechnology, methods......The yeast Saccharomyces cerevisiae is well a characterized microorganism and widely used as eukaryotic model organism as well as a key cell factory for bioproduction of various products. The latter comprise a large variety of scientifically and industrially relevant products such as low-value bulk...... chemicals and biofuels, food additives, high-value chemicals and recombinant proteins. Despite the recent achievements in the fields of systems biology and metabolic engineering together with availability of broad genetic engineering toolbox, the full potential of S. cerevisiae as a cell factory is not yet...

Achieving sustainable biomass conversion to energy and bio products

International Nuclear Information System (INIS)

Matteson, G. C.

2009-01-01

The present effort in to maximize biomass conversion-to-energy and bio products is examined in terms of sustain ability practices. New goals, standards in practice, measurements and certification are needed for the sustainable biomass industry. Sustainable practices produce biomass energy and products in a manner that is secure, renewable, accessible locally, and pollution free. To achieve sustainable conversion, some new goals are proposed. (Author)

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...

Microalgal biomass pretreatment for bioethanol production: a review

Directory of Open Access Journals (Sweden)

Jesús Velazquez-Lucio

2018-03-01

Full Text Available Biofuels derived from microalgae biomass have received a great deal of attention owing to their high potentials as sustainable alternatives to fossil fuels. Microalgae have a high capacity of CO2 fixation and depending on their growth conditions, they can accumulate different quantities of lipids, proteins, and carbohydrates. Microalgal biomass can, therefore, represent a rich source of fermentable sugars for third generation bioethanol production. The utilization of microalgal carbohydrates for bioethanol production follows three main stages: i pretreatment, ii saccharification, and iii fermentation. One of the most important stages is the pretreatment, which is carried out to increase the accessibility to intracellular sugars, and thus plays an important role in improving the overall efficiency of the bioethanol production process. Diverse types of pretreatments are currently used including chemical, thermal, mechanical, biological, and their combinations, which can promote cell disruption, facilitate extraction, and result in the modification the structure of carbohydrates as well as the production of fermentable sugars. In this review, the different pretreatments used on microalgae biomass for bioethanol production are presented and discussed. Moreover, the methods used for starch and total carbohydrates quantification in microalgae biomass are also briefly presented and compared.

Torrefaction of biomass for power production

DEFF Research Database (Denmark)

Saleh, Suriyati Binti

In order to increase the share of biomass for sustainable energy production, it will be an advantage to utilize fuels as straw, wood and waste on large suspension fired boilers. On a European scale, currently large straw resources are available that are not fully utilized for energy production...... rates, relatively low superheater temperatures have to be applied, which in turn lower the power efficiency. The idea for this Ph.D. project is to develop a biomass pretreatment method that could provide the heating value of the fuel for the boiler, but in a way such that the fuel is easily pulverized.......D. thesis focus on the following subjects: 1) the development of experimental procedures for a novel laboratory scale reactor (simultaneous torrefaction and grinding) and a study on the torrefaction of straw and wood; 2) study the influence of biomass chemical properties such as ash content, ash composition...

Embodied HANPP. Mapping the spatial disconnect between global biomass production and consumption

International Nuclear Information System (INIS)

Erb, Karl-Heinz; Krausmann, Fridolin; Haberl, Helmut; Lucht, Wolfgang

2009-01-01

Biomass trade results in a growing spatial disconnect between environmental impacts due to biomass production and the places where biomass is being consumed. The pressure on ecosystems resulting from the production of traded biomass, however, is highly variable between regions and products. We use the concept of embodied human appropriation of net primary production (HANPP) to map the spatial disconnect between net-producing and net-consuming regions. Embodied HANPP comprises total biomass withdrawals and land use induced changes in productivity resulting from the provision of biomass products. International net transfers of embodied HANPP are of global significance, amounting to 1.7 PgC/year. Sparsely populated regions are mainly net producers, densely populated regions net consumers, independent of development status. Biomass consumption and trade are expected to surge over the next decades, suggesting a need to sustainably manage supply and demand of products of ecosystems on a global level. (author)

Thermotolerant Yeast Strains Adapted by Laboratory Evolution Show Trade-Off at Ancestral Temperatures and Preadaptation to Other Stresses.

Science.gov (United States)

Caspeta, Luis; Nielsen, Jens

2015-07-21

A major challenge for the production of ethanol from biomass-derived feedstocks is to develop yeasts that can sustain growth under the variety of inhibitory conditions present in the production process, e.g., high osmolality, high ethanol titers, and/or elevated temperatures (≥ 40 °C). Using adaptive laboratory evolution, we previously isolated seven Saccharomyces cerevisiae strains with improved growth at 40 °C. Here, we show that genetic adaptations to high temperature caused a growth trade-off at ancestral temperatures, reduced cellular functions, and improved tolerance of other stresses. Thermotolerant yeast strains showed horizontal displacement of their thermal reaction norms to higher temperatures. Hence, their optimal and maximum growth temperatures increased by about 3 °C, whereas they showed a growth trade-off at temperatures below 34 °C. Computational analysis of the physical properties of proteins showed that the lethal temperature for yeast is around 49 °C, as a large fraction of the yeast proteins denature above this temperature. Our analysis also indicated that the number of functions involved in controlling the growth rate decreased in the thermotolerant strains compared with the number in the ancestral strain. The latter is an advantageous attribute for acquiring thermotolerance and correlates with the reduction of yeast functions associated with loss of respiration capacity. This trait caused glycerol overproduction that was associated with the growth trade-off at ancestral temperatures. In combination with altered sterol composition of cellular membranes, glycerol overproduction was also associated with yeast osmotolerance and improved tolerance of high concentrations of glucose and ethanol. Our study shows that thermal adaptation of yeast is suitable for improving yeast resistance to inhibitory conditions found in industrial ethanol production processes. Yeast thermotolerance can significantly reduce the production costs of biomass

Biomass and lipid production of Chlorella protothecoides under heterotrophic cultivation on a mixed waste substrate of brewer fermentation and crude glycerol.

Science.gov (United States)

Feng, Xiaoyu; Walker, Terry H; Bridges, William C; Thornton, Charles; Gopalakrishnan, Karthik

2014-08-01

Biomass and lipid accumulation of heterotrophic microalgae Chlorella protothecoides by supplying mixed waste substrate of brewer fermentation and crude glycerol were investigated. The biomass concentrations of the old and the new C. protothecoides strains on day 6 reached 14.07 and 12.73 g/L, respectively, which were comparable to those in basal medium with supplement of glucose and yeast extract (BM-GY) (14.47 g/L for old strains and 11.43 g/L for new strains) (P>0.05). Approximately 81.5% of total organic carbon and 65.1% of total nitrogen in the mixed waste were effectively removed. The accumulated lipid productivities of the old and the new C. protothecoides strains in BM-GY were 2.07 and 1.61 g/L/day, respectively, whereas in the mixed waste, lipid productivities could reach 2.12 and 1.81 g/L/day, respectively. Our result highlights a new approach of mixing carbon-rich and nitrogen-rich wastes as economical and practical alternative substrates for biofuel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biomass production in energy plantation of Prosopis juliflora

Energy Technology Data Exchange (ETDEWEB)

Gurumurti, K.

1984-09-01

Studies on time trends of biomass production by means of age series in energy plantations (spacing 1.3 x 1.3 m) of Prosopis juliflora is presented. The component biomass production at the age of 18, 24, 30, 36 and 48 months was determined. The results show considerable variation among the population of trees. However, distinct linear relationship between girth at breast height (GBH) and total height was discernible. The total biomass produced at 18, 24, 30, 36 and 48 months of age was 19.69, 41.39, 69.11, 114.62 and 148.63 dry tonnes per hectare, respectively. The corresponding figures for utilizable biomass (wood, bark and branch) were 14.63, 32.17, 50.59, 88.87 and 113.25 dry tonnes per hectare. At all the periods of study, branch component formed the major portion of total biomass being around 50 to 55%. Utilizable biomass was three-fourths of total biomass at all ages. The solar energy conversion efficiency ranged from 0.59% at 18 months to 1.68% at 48 months of age, the peak value being 1.87% at the age of 36 months. It is shown that the variables diameter and height can be used to reliably predict the biomass production in Prosopis juliflora with the help of the regression equations developed in the present study. It is concluded that Prosopis juliflora is an ideal candidate for energy plantations in semi arid and marginal lands, not only to meet the fuelwood demands but also to improve the soil fertility, for, this plant is a fast growing and nitrogen fixing leguminous tree.

Biomass pyrolysis/gasification for product gas production: the overall investigation of parametric effects

International Nuclear Information System (INIS)

Chen, G.; Andries, J.; Luo, Z.; Spliethoff, H.

2003-01-01

The conventional biomass pyrolysis/gasification process for production of medium heating value gas for industrial or civil applications faces two disadvantages, i.e. low gas productivity and the accompanying corrosion of downstream equipment caused by the high content of tar vapour contained in the gas phase. The objective of this paper is to overcome these disadvantages, and therefore, the effects of the operating parameters on biomass pyrolysis are investigated in a laboratory setup based on the principle of keeping the heating value of the gas almost unchanged. The studied parameters include reaction temperature, residence time of volatile phase in the reactor, physico-chemical pretreatment of biomass particles, heating rate of the external heating furnace and improvement of the heat and mass transfer ability of the pyrolysis reactor. The running temperature of a separate cracking reactor and the geometrical configuration of the pyrolysis reactor are also studied. However, due to time limits, different types of catalysts are not used in this work to determine their positive influences on biomass pyrolysis behaviour. The results indicate that product gas production from biomass pyrolysis is sensitive to the operating parameters mentioned above, and the product gas heating value is high, up to 13-15 MJ/N m 3

Biochemical conversions of lignocellulosic biomass for sustainable fuel-ethanol production in the upper Midwest

Science.gov (United States)

Brodeur-Campbell, Michael J.

Biofuels are an increasingly important component of worldwide energy supply. This research aims to understand the pathways and impacts of biofuels production, and to improve these processes to make them more efficient. In Chapter 2, a life cycle assessment (LCA) is presented for cellulosic ethanol production from five potential feedstocks of regional importance to the upper Midwest — hybrid poplar, hybrid willow, switchgrass, diverse prairie grasses, and logging residues — according to the requirements of Renewable Fuel Standard (RFS). Direct land use change emissions are included for the conversion of abandoned agricultural land to feedstock production, and computer models of the conversion process are used in order to determine the effect of varying biomass composition on overall life cycle impacts. All scenarios analyzed here result in greater than 60% reduction in greenhouse gas emissions relative to petroleum gasoline. Land use change effects were found to contribute significantly to the overall emissions for the first 20 years after plantation establishment. Chapter 3 is an investigation of the effects of biomass mixtures on overall sugar recovery from the combined processes of dilute acid pretreatment and enzymatic hydrolysis. Biomass mixtures studied were aspen, a hardwood species well suited to biochemical processing; balsam, a high-lignin softwood species, and switchgrass, an herbaceous energy crop with high ash content. A matrix of three different dilute acid pretreatment severities and three different enzyme loading levels was used to characterize interactions between pretreatment and enzymatic hydrolysis. Maximum glucose yield for any species was 70% of theoretical for switchgrass, and maximum xylose yield was 99.7% of theoretical for aspen. Supplemental β-glucosidase increased glucose yield from enzymatic hydrolysis by an average of 15%, and total sugar recoveries for mixtures could be predicted to within 4% by linear interpolation of the pure

Assessment of potential biomass energy production in China towards 2030 and 2050

Science.gov (United States)

Zhao, Guangling

2018-01-01

The objective of this paper is to provide a more detailed picture of potential biomass energy production in the Chinese energy system towards 2030 and 2050. Biomass for bioenergy feedstocks comes from five sources, which are agricultural crop residues, forest residues and industrial wood waste, energy crops and woody crops, animal manure, and municipal solid waste. The potential biomass production is predicted based on the resource availability. In the process of identifying biomass resources production, assumptions are made regarding arable land, marginal land, crops yields, forest growth rate, and meat consumption and waste production. Four scenarios were designed to describe the potential biomass energy production to elaborate the role of biomass energy in the Chinese energy system in 2030. The assessment shows that under certain restrictions on land availability, the maximum potential biomass energy productions are estimated to be 18,833 and 24,901 PJ in 2030 and 2050.

Production costs for SRIC Populus biomass

International Nuclear Information System (INIS)

Strauss, C.H.

1991-01-01

Production costs for short rotation, intensive culture (SRIC) Populus biomass were developed from commercial-sized plantations under investigation throughout the US. Populus hybrid planted on good quality agricultural sites at a density of 850 cuttings/acre was projected to yield an average of 7 ovendry (OD) tons/acre/year. Discounted cash-flow analysis of multiple rotations showed preharvest production costs of $14/ton (OD). Harvesting and transportation expenses would increase the delivered cost to $35/ton (OD). Although this total cost compared favorably with the regional market price for aspen (Populus tremuloides), future investments in SRIC systems will require the development of biomass energy markets

In vitro ability of beer fermentation residue and yeast-based products to bind aflatoxin B1

Directory of Open Access Journals (Sweden)

Fernanda Bovo

2015-06-01

Full Text Available This study aimed to verify the in vitro ability of beer fermentation residue (BFR containing Saccharomyces cerevisiae cells and five commercial products that differed in the viability and integrity of S. cerevisiae cells to remove aflatoxin B1 (AFB1 from a citrate-phosphate buffer solution (CPBS. BFR was collected at a microbrewery and prepared by drying and milling. The commercial yeast-based products were as follows: inactive intact yeast cells from beer alcoholic fermentation, inactive intact yeast cells from sugarcane alcoholic fermentation, hydrolyzed yeast cells, yeast cell walls and active yeast cells. Adsorption assays were performed in CPBS spiked with 1.0 μg AFB1/mL at pH 3.0 and 6.0 for a contact time of 60 min at room temperature. Analysis of AFB1 in the samples was performed by high performance liquid chromatography. AFB1 adsorption by the products ranged from 45.5% to 69.4% at pH 3.0 and from 24.0% to 63.8% at pH 6.0. The higher percentages (p 0.05 from commercial products containing inactive intact yeast cells. The results of this trial indicate that the yeast-based products tested, especially the BFR, have potential applications in animal feeds as a suitable biological method for reducing the adverse effects of aflatoxins.

In vitro ability of beer fermentation residue and yeast-based products to bind aflatoxin B1.

Science.gov (United States)

Bovo, Fernanda; Franco, Larissa Tuanny; Rosim, Roice Eliana; Barbalho, Ricardo; de Oliveira, Carlos Augusto Fernandes

2015-06-01

This study aimed to verify the in vitro ability of beer fermentation residue (BFR) containing Saccharomyces cerevisiae cells and five commercial products that differed in the viability and integrity of S. cerevisiae cells to remove aflatoxin B1 (AFB1) from a citrate-phosphate buffer solution (CPBS). BFR was collected at a microbrewery and prepared by drying and milling. The commercial yeast-based products were as follows: inactive intact yeast cells from beer alcoholic fermentation, inactive intact yeast cells from sugarcane alcoholic fermentation, hydrolyzed yeast cells, yeast cell walls and active yeast cells. Adsorption assays were performed in CPBS spiked with 1.0 μg AFB1/mL at pH 3.0 and 6.0 for a contact time of 60 min at room temperature. Analysis of AFB1 in the samples was performed by high performance liquid chromatography. AFB1 adsorption by the products ranged from 45.5% to 69.4% at pH 3.0 and from 24.0% to 63.8% at pH 6.0. The higher percentages (p 0.05) from commercial products containing inactive intact yeast cells. The results of this trial indicate that the yeast-based products tested, especially the BFR, have potential applications in animal feeds as a suitable biological method for reducing the adverse effects of aflatoxins.

Bioenergy potential of Ulva lactuca: Biomass yield, methane production and combustion

DEFF Research Database (Denmark)

Bruhn, Annette; Dahl, Jonas; Bangsø Nielsen, Henrik

2011-01-01

The biomass production potential at temperate latitudes (56°N), and the quality of the biomass for energy production (anaerobic digestion to methane and direct combustion) were investigated for the green macroalgae, Ulva lactuca. The algae were cultivated in a land based facility demonstrating...... in weight specific methane production compared to wet biomass. Ash and alkali contents are the main challenges in the use of U. lactuca for direct combustion. Application of a bio-refinery concept could increase the economical value of the U. lactuca biomass as well as improve its suitability for production...

Increase of ethanol productivity by cell-recycle fermentation of flocculating yeast.

Science.gov (United States)

Wang, F Z; Xie, T; Hui, M

2011-01-01

Using the recombinant flocculating Angel yeast F6, long-term repeated batch fermentation for ethanol production was performed and a high volumetric productivity resulted from half cells not washed and the optimum opportunity of residual glucose 20 g l(-1) of last medium. The obtained highest productivity was 2.07 g l-(1) h(-1), which was improved by 75.4% compared with that of 1.18 g l(-1) h(-1) in the first batch fermentation. The ethanol concentration reached 8.4% corresponding to the yield of 0.46 g g(-1). These results will contribute greatly to the industrial production of fuel ethanol using the commercial method with the flocculating yeast.

Post-fermentative production of glutathione by baker's yeast (S. cerevisiae) in compressed and dried forms.

Science.gov (United States)

Musatti, Alida; Manzoni, Matilde; Rollini, Manuela

2013-01-25

The study was aimed at investigating the best biotransformation conditions to increase intracellular glutathione (GSH) levels in samples of baker's yeast (Saccharomyces cerevisiae) employing either the commercially available compressed and dried forms. Glucose, GSH precursors amino acids, as well as other cofactors, were dissolved in a biotransformation solution and yeast cells were added (5%dcw). Two response surface central composite designs (RSCCDs) were performed in sequence: in the first step the influence of amino acid composition (cysteine, glycine, glutamic acid and serine) on GSH accumulation was investigated; once their formulation was set up, the influence of other components was studied. Initial GSH content was found 0.53 and 0.47%dcw for compressed and dried forms. GSH accumulation ability of baker's yeast in compressed form was higher at the beginning of shelf life, that is, in the first week, and a maximum of 2.04%dcw was obtained. Performance of yeast in dried form was not found satisfactory, as the maximum GSH level was 1.18%dcw. When cysteine lacks from the reaction solution, yeast cells do not accumulate GSH. With dried yeast, the highest GSH yields occurred when cysteine was set at 3 g/L, glycine and glutamic acid at least at 4 g/L, without serine. Employing compressed yeast, the highest GSH yields occurred when cysteine and glutamic acid were set at 2-3 g/L, while glycine and serine higher than 2 g/L. Results allowed to set up an optimal and feasible procedure to obtain GSH-enriched yeast biomass, with up to threefold increase with respect to initial content. Copyright © 2012 Elsevier B.V. All rights reserved.

Engineering yeast metabolism for production of terpenoids for use as perfume ingredients, pharmaceuticals and biofuels.

Science.gov (United States)

Zhang, Yueping; Nielsen, Jens; Liu, Zihe

2017-12-01

Terpenoids represent a large class of natural products with significant commercial applications. These chemicals are currently mainly obtained through extraction from plants and microbes or through chemical synthesis. However, these sources often face challenges of unsustainability and low productivity. In order to address these issues, Escherichia coli and yeast have been metabolic engineered to produce non-native terpenoids. With recent reports of engineering yeast metabolism to produce several terpenoids at high yields, it has become possible to establish commercial yeast production of terpenoids that find applications as perfume ingredients, pharmaceuticals and advanced biofuels. In this review, we describe the strategies to rewire the yeast pathway for terpenoid biosynthesis. Recent advances will be discussed together with challenges and perspectives of yeast as a cell factory to produce different terpenoids. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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...

Binding and Conversion of Selenium in Candida utilis ATCC 9950 Yeasts in Bioreactor Culture

Directory of Open Access Journals (Sweden)

Marek Kieliszek

2017-02-01

Full Text Available Selenium is considered an essential component of all living organisms. The use of yeasts as a selenium supplement in human nutrition has gained much interest over the last decade. The accumulation and biochemical transformation of selenium in yeast cells is particularly interesting to many researchers. In this article, we present the results of the determination of selenium and selenomethionine content in the biomass of feed yeast Candida utilis ATCC 9950 obtained from the culture grown in a bioreactor. The results indicated that C. utilis cells performed the biotransformation of inorganic selenium(IV to organic derivatives (e.g., selenomethionine. Selenium introduced (20–30 mg Se4+∙L−1 to the experimental media in the form of sodium(IV selenite (Na2SeO3 salt caused a significant increase in selenium content in the biomass of C. utilis,irrespective of the concentration. The highest amount of selenium (1841 μg∙gd.w.−1 was obtained after a 48-h culture in media containing 30 mg Se4+∙L−1. The highest content of selenomethionine (238.8 μg∙gd.w.−1 was found after 48-h culture from the experimental medium that was supplemented with selenium at a concentration of 20 mg Se4+∙L−1. Biomass cell in the cultures supplemented with selenium ranged from 1.5 to 14.1 g∙L−1. The results of this study indicate that yeast cell biomass of C. utilis enriched mainly with the organic forms of selenium can be a valuable source of protein. It creates the possibility of obtaining selenium biocomplexes that can be used in the production of protein-selenium dietary supplements for animals and humans

Antioxidant defense parameters as predictive biomarkers for fermentative capacity of active dried wine yeast.

Science.gov (United States)

Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

2014-08-01

The production of active dried yeast (ADY) is a common practice in industry for the maintenance of yeast starters and as a means of long term storage. The process, however, causes multiple cell injuries, with oxidative damage being one of the most important stresses. Consequentially, dehydration tolerance is a highly appreciated property in yeast for ADY production. In this study we analyzed the cellular redox environment in three Saccharomyces cerevisiae wine strains, which show markedly different fermentative capacities after dehydration. To measure/quantify the effect of dehydration on the S. cerevisiae strains, we used: (i) fluorescent probes; (ii) antioxidant enzyme activities; (ii) intracellular damage; (iii) antioxidant metabolites; and (iv) gene expression, to select a minimal set of biochemical parameters capable of predicting desiccation tolerance in wine yeasts. Our results show that naturally enhanced antioxidant defenses prevent oxidative damage after wine yeast biomass dehydration and improve fermentative capacity. Based on these results we chose four easily assayable parameters/biomarkers for the selection of industrial yeast strains of interest for ADY production: trehalose and glutathione levels, and glutathione reductase and catalase enzymatic activities. Yeast strains selected in accordance with this process display high levels of trehalose, low levels of oxidized glutathione, a high induction of glutathione reductase activity, as well as a high basal level and sufficient induction of catalase activity, which are properties inherent in superior ADY strains. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improving yeast strains using recyclable integration cassettes, for the production of plant terpenoids

Directory of Open Access Journals (Sweden)

Johnson Christopher B

2011-01-01

Full Text Available Abstract Background Terpenoids constitute a large family of natural products, attracting commercial interest for a variety of uses as flavours, fragrances, drugs and alternative fuels. Saccharomyces cerevisiae offers a versatile cell factory, as the precursors of terpenoid biosynthesis are naturally synthesized by the sterol biosynthetic pathway. Results S. cerevisiae wild type yeast cells, selected for their capacity to produce high sterol levels were targeted for improvement aiming to increase production. Recyclable integration cassettes were developed which enable the unlimited sequential integration of desirable genetic elements (promoters, genes, termination sequence at any desired locus in the yeast genome. The approach was applied on the yeast sterol biosynthetic pathway genes HMG2, ERG20 and IDI1 resulting in several-fold increase in plant monoterpene and sesquiterpene production. The improved strains were robust and could sustain high terpenoid production levels for an extended period. Simultaneous plasmid-driven co-expression of IDI1 and the HMG2 (K6R variant, in the improved strain background, maximized monoterpene production levels. Expression of two terpene synthase enzymes from the sage species Salvia fruticosa and S. pomifera (SfCinS1, SpP330 in the modified yeast cells identified a range of terpenoids which are also present in the plant essential oils. Co-expression of the putative interacting protein HSP90 with cineole synthase 1 (SfCinS1 also improved production levels, pointing to an additional means to improve production. Conclusions Using the developed molecular tools, new yeast strains were generated with increased capacity to produce plant terpenoids. The approach taken and the durability of the strains allow successive rounds of improvement to maximize yields.

Heterologous expression of a deuterated membrane-integrated receptor and partial deuteration in methylotrophic yeasts

International Nuclear Information System (INIS)

Massou, S.; Puech, V.; Talmont, F.; Demange, P.; Lindley, N.D.; Tropis, M.; Milon, A.

1999-01-01

Methylotrophic yeast has previously been shown to be an excellent system for the cost-effective production of perdeuterated biomass and for the heterologous expression of membrane receptors. A protocol for the expression of 85% deuterated, functional human μ-opiate receptor was established. For partially deuterated biomass, deuteration level and distribution were determined for fatty acids, amino acids and carbohydrates. It was shown that prior to biosynthesis of lipids and amino acids (and of carbohydrates, to a lower extent), exchange occurs between water and methanol hydrogen atoms, so that 80%-90% randomly deuterated biomass and over-expressed proteins may be obtained using only deuterated water

Superstructure optimization of biodiesel production from microalgal biomass

DEFF Research Database (Denmark)

Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

2013-01-01

In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass...... for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case study. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed and their significances are discussed....

Production of chemicals and fuels from biomass

Science.gov (United States)

Qiao, Ming; Woods, Elizabeth; Myren, Paul; Cortright, Randy; Kania, John

2018-01-23

Methods, reactor systems, and catalysts are provided for converting in a continuous process biomass to fuels and chemicals, including methods of converting the water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

Expanding a dynamic flux balance model of yeast fermentation to genome-scale

Science.gov (United States)

2011-01-01

Background Yeast is considered to be a workhorse of the biotechnology industry for the production of many value-added chemicals, alcoholic beverages and biofuels. Optimization of the fermentation is a challenging task that greatly benefits from dynamic models able to accurately describe and predict the fermentation profile and resulting products under different genetic and environmental conditions. In this article, we developed and validated a genome-scale dynamic flux balance model, using experimentally determined kinetic constraints. Results Appropriate equations for maintenance, biomass composition, anaerobic metabolism and nutrient uptake are key to improve model performance, especially for predicting glycerol and ethanol synthesis. Prediction profiles of synthesis and consumption of the main metabolites involved in alcoholic fermentation closely agreed with experimental data obtained from numerous lab and industrial fermentations under different environmental conditions. Finally, fermentation simulations of genetically engineered yeasts closely reproduced previously reported experimental results regarding final concentrations of the main fermentation products such as ethanol and glycerol. Conclusion A useful tool to describe, understand and predict metabolite production in batch yeast cultures was developed. The resulting model, if used wisely, could help to search for new metabolic engineering strategies to manage ethanol content in batch fermentations. PMID:21595919

Electricity production from microbial fuel cell by using yeast

International Nuclear Information System (INIS)

Vorasingha, A.; Souvakon, C.; Boonchom, K.

2006-01-01

The continuous search for methods to generate electricity from renewable sources such as water, solar energy, wind, nuclear or chemicals was discussed with particular focus on attaining the full power of the microbial fuel cell (MFC). Under ideal environmental conditions, the only byproducts of a biofuel cell would be water and carbon dioxide (CO 2 ). The production of energy from renewables such as biomass is important for sustainable development and reducing global emissions of CO 2 . Hydrogen can also be an important component of an energy infrastructure that reduces CO 2 emissions if the hydrogen is produced from renewable sources and used in fuel cells. Hydrogen gas can be biologically produced at high concentration from the fermentation of high sugar substrates such as glucose and sucrose. Some of the issues of MFC design were addressed, including the use of cheap substrates to derive microbial electricity. In the MFC, yeast donates electrons to a chemical electron mediator, which in turn transfers the electrons to an electrode, producing electricity. Experimental results showed that glucose yielded the highest peak voltage, but a semi-processed sugar and molasses were similar to glucose in the electricity production pattern. It was noted that this technology is only at the research stages, and more research is needed before household microbial fuel cells can be made available for producing power for prolonged periods of time. Future research efforts will focus on increasing the efficiency, finding alternatives to hazardous electron mediators and finding new microbes. 12 refs., 6 figs

Fuels production by the thermochemical transformation of the biomass; La production de carburants par transformation thermochimique de la biomasse

Energy Technology Data Exchange (ETDEWEB)

Claudet, G. [CEA, 75 - Paris (France)

2005-07-01

The biomass is a local and renewable energy source, presenting many advantages. This paper proposes to examine the biomass potential in France, the energy valorization channels (thermochemical chains of thermolysis and gasification) with a special interest for the hydrogen production and the research programs oriented towards the agriculture and the forest. (A.L.B.)

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.

Yeast dynamics during spontaneous fermentation of mawe and tchoukoutou, two traditional products from Benin

DEFF Research Database (Denmark)

Greppi, Anna; Rantisou, Kalliopi; Padonou, Wilfrid

2013-01-01

Mawe and tchoukoutou are two traditional fermented foods largely consumed in Benin, West Africa. Their preparations remain as a house art and they are the result of spontaneous fermentation processes. In this study, dynamics of the yeast populations occurring during spontaneous fermentations...... of mawe and tchoukoutou were investigated using both culture-dependent and -independent approaches. For each product, two productions were followed. Samples were taken at different fermentation times and yeasts were isolated, resulting in the collection of 177 isolates. They were identified by the PCR......-DGGE technique followed by the sequencing of the D1/D2 domain of the 26S rRNA gene. The predominant yeast species identified were typed by rep-PCR. Candida krusei was the predominant yeast species in mawe fermentation followed by Candida glabrata and Kluyveromyces marxianus. Other yeast species were detected...

Biomass Energy Production in California: The Case for a Biomass Policy Initiative; Final Report

Energy Technology Data Exchange (ETDEWEB)

Morris, G.

2000-12-14

During the 1980s California developed the largest and most divers biomass energy industry in the world. Biomass energy production has become an important component of the state's environmental infrastructure, diverting solid wastes from open burning and disposal in landfills to a beneficial use application.

Biomass productivity improvement for eastern cottonwood

Science.gov (United States)

Terry L. Robison; Randy J. Rousseau; Jianwei Zhang

2006-01-01

Eastern cottonwood ( Populus deltoides Marsh.) is grown in plantations by MeadWestvaco for use at its Wickliffe Kentucky Fine Papers Mill1. Genetic and productivity research over the past two decades have led to significant increases in biomass yield while reducing production costs.Initially, genetic research identified fast growing...

Biomass and pigments production in photosynthetic bacteria wastewater treatment: Effects of photoperiod.

Science.gov (United States)

Zhou, Qin; Zhang, Panyue; Zhang, Guangming; Peng, Meng

2015-08-01

This study aimed at enhancing the bacterial biomass and pigments production in together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via using different photoperiods. Different light/dark cycles and light/dark cycle frequencies were examined. Results showed that PSB had the highest biomass production, COD removal and biomass yield, and light energy efficiency with light/dark cycle of 2h/1h. The corresponding biomass, COD removal and biomass yield reached 2068mg/L, 90.3%, and 0.38mg-biomass/mg-COD-removal, respectively. PSB showed higher biomass production and biomass yield with higher light/dark cycle frequency. Mechanism analysis showed within a light/dark cycle from 1h/2h to 2h/1h, the carotenoid and bacteriochlorophyll production increased with an increase in light/dark cycle. Moreover, the pigment contents were much higher with lower frequency of 2-4 times/d. Copyright © 2015 Elsevier Ltd. All rights reserved.

Hydrogen from algal biomass: A review of production process

Directory of Open Access Journals (Sweden)

Archita Sharma

2017-09-01

Full Text Available Multifariousness of biofuel sources has marked an edge to an imperative energy issue. Production of hydrogen from microalgae has been gathering much contemplation right away. But, mercantile production of microalgae biofuels considering bio-hydrogen is still not practicable because of low biomass concentration and costly down streaming processes. This review has taken up the hydrogen production by microalgae. Biofuels are the up and coming alternative to exhaustible, environmentally and unsafe fossil fuels. Algal biomass has been considered as an enticing raw material for biofuel production, these days photobioreactors and open-air systems are being used for hydrogen production from algal biomass. The formers allow the careful cultivation control whereas the latter ones are cheaper and simpler. A contemporary, encouraging optimization access has been included called algal cell immobilization on various matrixes which has resulted in marked increase in the productivity per volume of a reactor and addition of the hydrogen-production phase.

Reflections on the aerobic fermentation stoichiometry of crabtree positive yeasts

DEFF Research Database (Denmark)

Villadsen, John; Jørgensen, Sten Bay

2014-01-01

In this communication a stoichiometric steady state model for Crabtree positive yeasts is proposed. The model is sufficiently simple to be corroborated by experimental data on the key metabolic events around Dcrit. The key feature of the model is that the bottleneck aperture for biomass production...... in the model of Sonnleitner and Käppeli, 1986 shrinks abruptly at Dcrit and continues to decrease with increasing dilution rate. A black box stoichiometric analysis of experiments reported in literature indicates that production of acetaldehyde might account for the abrupt shrinkage through a severe poisoning...

Integrated production of warm season grasses and agroforestry for biomass production

Energy Technology Data Exchange (ETDEWEB)

Samson, R.; Omielan, J. [Resource Efficient Agricultural Production-Canada, Ste, Anne de Bellevue, Quebec (Canada); Girouard, P.; Henning, J. [McGill Univ., Ste. Anne de Bellevue, Quebec (Canada)

1993-12-31

Increased research on C{sub 3} and C{sub 4} perennial biomass crops is generating a significant amount of information on the potential of these crops to produce large quantities of low cost biomass. In many parts of North America it appears that both C{sub 3} and C{sub 4} species are limited by water availability particularly on marginal soils. In much of North America, rainfall is exceeded by evaporation. High transpiration rates by fast growing trees and rainfall interception by the canopy appear to indicate that this can further exacerbate the problem of water availability. C{sub 4} perennial grasses appear to have distinct advantages over C{sub 3} species planted in monoculture systems particularly on marginal soils. C{sub 4} grasses historically predominated over much of the land that is now available for biomass production because of their adaptation to low humidity environments and periods of low soil moisture. The planting of short rotation forestry (SRF) species in an energy agroforestry system is proposed as an alternative production strategy which could potentially alleviate many of the problems associated with SRF monocultures. Energy agroforestry would be complementary to both production of conventional farm crops and C{sub 4} perennial biomass crops because of beneficial microclimatic effects.

A Review on Biomass Torrefaction Process and Product Properties

Energy Technology Data Exchange (ETDEWEB)

Jaya Shankar Tumuluru; Shahab Sokhansanj; Christopher T. Wright; J. Richard Hess; Richard D. Boardman

2011-08-01

Biomass Torrefaction is gaining attention as an important preprocessing step to improve the quality of biomass in terms of physical properties and chemical composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of approximately 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-280 C. Thus, the process can be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, which produces a final product that will have a lower mass but a higher heating value. The present review work looks into (a) torrefaction process and different products produced during the process and (b) solid torrefied material properties which include: (i) physical properties like moisture content, density, grindability, particle size distribution and particle surface area and pelletability; (ii) chemical properties like proximate and ultimate composition; and (iii) storage properties like off-gassing and spontaneous combustion.

High-temperature fermentation. How can processes for ethanol production at high temperatures become superior to the traditional process using mesophilic yeast?

Energy Technology Data Exchange (ETDEWEB)

Abdel-Banat, Babiker M.A.; Hoshida, Hisashi; Nonklang, Sanom; Akada, Rinji [Yamaguchi Univ. Graduate School of Medicine, Ube (Japan). Dept. of Applied Molecular Bioscience; Ano, Akihiko [Iwata Chemical Co. Ltd. (Japan)

2010-01-15

The process of ethanol fermentation has a long history in the production of alcoholic drinks, but much larger scale production of ethanol is now required to enable its use as a substituent of gasoline fuels at 3%, 10%, or 85% (referred to as E3, E10, and E85, respectively). Compared with fossil fuels, the production costs are a major issue for the production of fuel ethanol. There are a number of possible approaches to delivering cost-effective fuel ethanol production from different biomass sources, but we focus in our current report on high-temperature fermentation using a newly isolated thermotolerant strain of the yeast Kluyveromyces marxianus. We demonstrate that a 5 C increase only in the fermentation temperature can greatly affect the fuel ethanol production costs. We contend that this approach may also be applicable to the other microbial fermentations systems and propose that thermotolerant mesophilic microorganisms have considerable potential for the development of future fermentation technologies. (orig.)

Microalgal biomass production pathways: evaluation of life cycle environmental impacts.

Science.gov (United States)

Zaimes, George G; Khanna, Vikas

2013-06-20

Microalgae are touted as an attractive alternative to traditional forms of biomass for biofuel production, due to high productivity, ability to be cultivated on marginal lands, and potential to utilize carbon dioxide (CO2) from industrial flue gas. This work examines the fossil energy return on investment (EROIfossil), greenhouse gas (GHG) emissions, and direct Water Demands (WD) of producing dried algal biomass through the cultivation of microalgae in Open Raceway Ponds (ORP) for 21 geographic locations in the contiguous United States (U.S.). For each location, comprehensive life cycle assessment (LCA) is performed for multiple microalgal biomass production pathways, consisting of a combination of cultivation and harvesting options. Results indicate that the EROIfossil for microalgae biomass vary from 0.38 to 1.08 with life cycle GHG emissions of -46.2 to 48.9 (g CO2 eq/MJ-biomass) and direct WDs of 20.8 to 38.8 (Liters/MJ-biomass) over the range of scenarios analyzed. Further anaylsis reveals that the EROIfossil for production pathways is relatively location invariant, and that algae's life cycle energy balance and GHG impacts are highly dependent on cultivation and harvesting parameters. Contrarily, algae's direct water demands were found to be highly sensitive to geographic location, and thus may be a constraining factor in sustainable algal-derived biofuel production. Additionally, scenarios with promising EROIfossil and GHG emissions profiles are plagued with high technological uncertainty. Given the high variability in microalgae's energy and environmental performance, careful evaluation of the algae-to-fuel supply chain is necessary to ensure the long-term sustainability of emerging algal biofuel systems. Alternative production scenarios and technologies may have the potential to reduce the critical demands of biomass production, and should be considered to make algae a viable and more efficient biofuel alternative.

Effect of diverse ecological conditions on biomass production of ...

African Journals Online (AJOL)

Kangaroo grass native to Australia is known as the best grass to grow on different environmental and soil conditions. Biomass production of any grass is the key factor to estimate that if the grass could fulfill the animal requirements. Biomass production of kangaroo grass was estimated in this study at three growth stages on ...

Biomass gasification for energy production

Energy Technology Data Exchange (ETDEWEB)

Lundberg, H.; Morris, M.; Rensfelt, E. [TPS Termiska Prosesser Ab, Nykoeping (Sweden)

1997-12-31

Biomass and waste are becoming increasingly interesting as fuels for efficient and environmentally sound power generation. Circulating fluidized bed (CFB) gasification for biomass and waste has been developed and applied to kilns both in the pulp and paper industry and the cement industry. A demonstration plant in Greve-in- Chianti, Italy includes two 15 MW{sub t}h RDF-fuelled CFB gasifiers of TPS design, the product gas from which is used in a cement kiln or in steam boiler for power generation. For CFB gasification of biomass and waste to reach a wider market, the product gas has to be cleaned effectively so that higher fuel to power efficiencies can be achieved by utilizing power cycles based on engines or gas turbines. TPS has developed both CFB gasification technology and effective secondary stage tar cracking technology. The integrated gasification - gas-cleaning technology is demonstrated today at pilot plant scale. To commercialise the technology, the TPS`s strategy is to first demonstrate the process for relatively clean fuels such as woody biomass and then extend the application to residues from waste recycling. Several demonstration projects are underway to commercialise TPS`s gasification and gas cleaning technology. In UK the ARBRE project developed by ARBRE Energy will construct a gasification plant at Eggborough, North Yorkshire, which will provide gas to a gas turbine and steam turbine generation system, producing 10 MW and exporting 8 Mw of electricity. It has been included in the 1993 tranche of the UK`s Non Fossil Fuel Obligation (NFFO) and has gained financial support from EC`s THERMIE programme as a targeted BIGCC project. (author)

Biomass gasification for energy production

Energy Technology Data Exchange (ETDEWEB)

Lundberg, H; Morris, M; Rensfelt, E [TPS Termiska Prosesser Ab, Nykoeping (Sweden)

1998-12-31

Biomass and waste are becoming increasingly interesting as fuels for efficient and environmentally sound power generation. Circulating fluidized bed (CFB) gasification for biomass and waste has been developed and applied to kilns both in the pulp and paper industry and the cement industry. A demonstration plant in Greve-in- Chianti, Italy includes two 15 MW{sub t}h RDF-fuelled CFB gasifiers of TPS design, the product gas from which is used in a cement kiln or in steam boiler for power generation. For CFB gasification of biomass and waste to reach a wider market, the product gas has to be cleaned effectively so that higher fuel to power efficiencies can be achieved by utilizing power cycles based on engines or gas turbines. TPS has developed both CFB gasification technology and effective secondary stage tar cracking technology. The integrated gasification - gas-cleaning technology is demonstrated today at pilot plant scale. To commercialise the technology, the TPS`s strategy is to first demonstrate the process for relatively clean fuels such as woody biomass and then extend the application to residues from waste recycling. Several demonstration projects are underway to commercialise TPS`s gasification and gas cleaning technology. In UK the ARBRE project developed by ARBRE Energy will construct a gasification plant at Eggborough, North Yorkshire, which will provide gas to a gas turbine and steam turbine generation system, producing 10 MW and exporting 8 Mw of electricity. It has been included in the 1993 tranche of the UK`s Non Fossil Fuel Obligation (NFFO) and has gained financial support from EC`s THERMIE programme as a targeted BIGCC project. (author)

A study of ethanol production of yeast cells immobilized with polymer carrier produced by radiation polymerization

International Nuclear Information System (INIS)

Lu Zhaoxin; Fujimura, Takashi

1993-01-01

Polymer carriers, poly(hydroxyethyl acrylate(HEA)-methoxy polyethylene glycol methylacrylate (M-23G)) and poly(hydroxyethyl acrylate(HEA)-glycidyl methylacrylate (GMA)) used for the immobilization of yeast cells were prepared by radiation polymerization at low temperature. Yeast cells were immobilized through adhesion and multiplication of yeast cells. The ethanol productivity of immobilized yeast cells with these carriers was related to the monomer composition of polymers and the optimum monomer composition was 20%:10% in poly(HEA-M-23G) and 17%:6% in poly(HEA-GMA). In this case, the ethanol productivity of immobilized yeast cells was about 4 times that of cells in free system. The relationship between the activity of immobilized yeast cells and the water content of the polymer carrier were also discussed. (author)

Thermodynamic evaluation of biomass-to-biofuels production systems

NARCIS (Netherlands)

Piekarczyk, W.; Czarnowska, L.; Ptasinski, K.J.; Stanek, W.

2013-01-01

Biomass is a renewable feedstock for producing modern energy carriers. However, the usage of biomass is accompanied by possible drawbacks, mainly due to limitation of land and water, and competition with food production. In this paper, the analysis concerns so-called second generation biofuels, like

Efficiency analysis of hydrogen production methods from biomass

NARCIS (Netherlands)

Ptasinski, K.J.

2008-01-01

Abstract: Hydrogen is considered as a universal energy carrier for the future, and biomass has the potential to become a sustainable source of hydrogen. This article presents an efficiency analysis of hydrogen production processes from a variety of biomass feedstocks by a thermochemical method –

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

Exopolysaccharide production by Lactobacillus confusus TISTR 1498 using coconut water as an alternative carbon source: the effect of peptone, yeast extract and beef extract

Directory of Open Access Journals (Sweden)

Phisit Seesuriyachan

2011-08-01

Full Text Available Coconut water (CW is a by-product of food industry and has little value in Thailand. It is usually discarded as a wasteinto the environment. Consequently, we developed a value added process of exopolysaccharide (EPS production usingLactobacillus confusus TISTR 1498 and coconut water. The effect of three expensive supplements (peptone, yeast extractand beef extract on EPS and biomass production was investigated at 35°C for 24 h. Using a mod-MRS-CW medium, preparedby replacing the de-ionized water with 100% CW and supplemented with 20 g/l crystalline sucrose and a reduced quantity(50% of the three expensive supplements (5 g/l of peptone, 2.5 g/l of yeast extract, and 2.5 g/l of beef extract gave thehighest yield of EPS (12.3 g/l. By optimizing the conditions for fermentation (pH 5.5, agitation speed at 50 rpm and initialsucrose concentration of 100 g/l, EPS yield increased up to 38.2 g/l. When compared with the modified MRS medium, themedium supplemented with CW was found to be suitable for the reduction of cost spent on the organic nitrogen and growthfactors (savings close to 50%.

Production of chemicals and fuels from biomass

Energy Technology Data Exchange (ETDEWEB)

Woods, Elizabeth; Qiao, Ming; Myren, Paul; Cortright, Randy D.; Kania, John

2015-12-15

Described are methods, reactor systems, and catalysts for converting biomass to fuels and chemicals in a batch and/or continuous process. The process generally involves the conversion of water insoluble components of biomass, such as hemicellulose, cellulose and lignin, to volatile C.sub.2+O.sub.1-2 oxygenates, such as alcohols, ketones, cyclic ethers, esters, carboxylic acids, aldehydes, and mixtures thereof. In certain applications, the volatile C.sub.2+O.sub.1-2 oxygenates can be collected and used as a final chemical product, or used in downstream processes to produce liquid fuels, chemicals and other products.

Food and disturbance effects on Arctic benthic biomass and production size spectra

Science.gov (United States)

Górska, Barbara; Włodarska-Kowalczuk, Maria

2017-03-01

Body size is a fundamental biological unit that is closely coupled to key ecological properties and processes. At the community level, changes in size distributions may influence energy transfer pathways in benthic food webs and ecosystem carbon cycling; nevertheless they remain poorly explored in benthic systems, particularly in the polar regions. Here, we present the first assessment of the patterns of benthic biomass size spectra in Arctic coastal sediments and explore the effects of glacial disturbance and food availability on the partitioning of biomass and secondary productivity among size-defined components of benthic communities. The samples were collected in two Arctic fjords off west Spitsbergen (76 and 79°N), at 6 stations that represent three regimes of varying food availability (indicated by chlorophyll a concentration in the sediments) and glacial sedimentation disturbance intensity (indicated by sediment accumulation rates). The organisms were measured using image analysis to assess the biovolume, biomass and the annual production of each individual. The shape of benthic biomass size spectra at most stations was bimodal, with the location of a trough and peaks similar to those previously reported in lower latitudes. In undisturbed sediments macrofauna comprised 89% of the total benthic biomass and 56% of the total production. The lower availability of food resources seemed to suppress the biomass and secondary production across the whole size spectra (a 6-fold decrease in biomass and a 4-fold decrease in production in total) rather than reshape the spectrum. At locations where poor nutritional conditions were coupled with disturbance, the biomass was strongly reduced in selected macrofaunal size classes (class 10 and 11), while meiofaunal biomass and production were much higher, most likely due to a release from macrofaunal predation and competition pressure. As a result, the partitioning of benthic biomass and production shifted towards meiofauna

Development of Value-Added Products from Residual Algae to Biomass

Energy Technology Data Exchange (ETDEWEB)

Behnke, Craig [Sapphire Energy, San Diego, CA (United States)

2016-02-29

DOE Award # EE0000393 was awarded to fund research into the development of beneficial uses of surplus algal biomass and the byproducts of biofuel production. At the time of award, Sapphire’s intended fuel production pathway was a fairly conventional extraction of lipids from biomass, resulting in a defatted residue which could be processed using anaerobic digestion. Over the lifetime of the award, we conducted extensive development work and arrived at the conclusion that anaerobic digestion presented significant technical challenges for this high-nitrogen, high-ash, and low carbon material. Over the same timeframe, Sapphire’s fuel production efforts came to focus on hydrothermal liquefaction. As a result of this technology focus, the residue from fuel production became unsuitable for either anaerobic digestion (or animal feed uses). Finally, we came to appreciate the economic opportunity that the defatted biomass could represent in the animal feed space, as well as understanding the impact of seasonal production on a biofuels extraction plant, and sought to develop uses for surplus biomass produced in excess of the fuel production unit’s capacity.

Biomass production as renewable energy resource at reclaimed Serbian lignite open-cast mines

Directory of Open Access Journals (Sweden)

Jakovljević Milan

2015-01-01

Full Text Available The main goal of this paper is the overview of the scope and dynamics of biomass production as a renewable energy source for substitution of coal in the production of electrical energy in the Kolubara coal basin. In order to successfully realize this goal, it was necessary to develop a dynamic model of the process of coal production, overburden dumping and re-cultivation of dumping sites by biomass planting. The results obtained by simulation of the dynamic model of biomass production in Kolubara mine basin until year 2045 show that 6870 hectares of overburden waste dumps will be re-cultivated by biomass plantations. Biomass production modeling point out the significant benefits of biomass production by planting the willow Salix viminalis cultivated for energy purposes. Under these conditions, a 0.6 % participation of biomass at the end of the period of intensive coal production, year 2037, is achieved. With the decrease of coal production to 15 million tons per year, this percentage steeply rises to 1.4 % in 2045. This amount of equivalent tons of coal from biomass can be used for coal substitution in the production of electrical energy. [Projekat Ministarstva nauke Republike Srbije, br. TR 33039

Biosurfactant production using mixed cultures under non-aseptic conditions

International Nuclear Information System (INIS)

Vipulanandan, C.; Ghurye, G.L.; Willson, R.C.

1994-01-01

The use of surfactants is of increasing interest for remediation of petroleum hydrocarbons in groundwater and soil. Surfactants increase the accessibility of adsorbed hydrocarbons and mobilize immiscible petroleum hydrocarbons for treatment. Biosurfactants have the advantage of biodegradability and non-toxicity over their synthetic counterparts, and can be produced from renewable sources. In this study the production of biosurfactant from molasses was investigated in continuously stirred batch reactors. The effects of substrate concentration, yeast extract and peptone on biomass accumulation and biosurfactant production were investigated. Biosurfactant production was quantified by surface tension reduction and critical micelle dilution (CMD). Biosurfactant production was directly correlated with biomass production, and was improved with the addition of yeast extract. Centrifugation of the whole broth reduced surface tension. The performance of the biosurfactant produced from molasses under non-aseptic condition is comparable to other published results

Simultaneous saccharification and fermentation (SSF) using cellobiose fermenting yeast Brettanomyces custersii

Science.gov (United States)

Spindler, Diane D.; Grohmann, Karel; Wyman, Charles E.

1992-01-01

A process for producing ethanol from plant biomass includes forming a substrate from the biomass with the substrate including hydrolysates of cellulose and hemicellulose. A species of the yeast Brettanomyces custersii (CBS 5512), which has the ability to ferment both cellobiose and glucose to ethanol, is then selected and isolated. The substrate is inoculated with this yeast, and the inoculated substrate is then fermented under conditions favorable for cell viability and conversion of hydrolysates to ethanol.

Biomass production for direct generation of energy

International Nuclear Information System (INIS)

1992-01-01

In continuing its activities for the formation of public opinion the Deutsche Farming Association) held a colloquium in 1991 on the issue of biomass production and combustion. Its aim was to gather all current knowledge on this issue and, for the first time, to make a comprehensive appraisal of it. The following aspects were dealt with: Abatement of atmospheric pollution, ecologically oriented production, nature conservation, organisation of decentralized power plant operating corporations, state of the art in combustion technology, operational calculations and, not least, agrarin-political framework conditions. The meeting yielded important statements on remarkable innovations in the area of ecological biomass production and for its utilization as an energy source together with the conventional energy sources of oil, gas, coal and nuclear energy. (orig.) [de

(DHOase) production by Saccharomyces cerevisiae MNJ3 (pMNJ1)

African Journals Online (AJOL)

STORAGESEVER

2009-01-05

Jan 5, 2009 ... (pMNJ1) and allow sufficient biomass production to ensure DHoase's purification were investigated. We used as basal medium the Yeast Carbon Base (YCB; Difco), especially designed for studies of nitrogen metabolism in yeasts. Thus the effects of an additional carbon source (glucose or citric acid) and ...

Method for creating high carbon content products from biomass oil

Science.gov (United States)

Parker, Reginald; Seames, Wayne

2012-12-18

In a method for producing high carbon content products from biomass, a biomass oil is added to a cracking reactor vessel. The biomass oil is heated to a temperature ranging from about 100.degree. C. to about 800.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to crack the biomass oil. Tar is separated from the cracked biomass oil. The tar is heated to a temperature ranging from about 200.degree. C. to about 1500.degree. C. at a pressure ranging from about vacuum conditions to about 20,700 kPa for a time sufficient to reduce the tar to a high carbon content product containing at least about 50% carbon by weight.

Succinic acid production by Actinobacillus succinogenes using hydrolysates of spent yeast cells and corn fiber.

Science.gov (United States)

Chen, Ke-Quan; Li, Jian; Ma, Jiang-Feng; Jiang, Min; Wei, Ping; Liu, Zhong-Min; Ying, Han-Jie

2011-01-01

The enzymatic hydrolysate of spent yeast cells was evaluated as a nitrogen source for succinic acid production by Actinobacillus succinogenes NJ113, using corn fiber hydrolysate as a carbon source. When spent yeast cell hydrolysate was used directly as a nitrogen source, a maximum succinic acid concentration of 35.5 g/l was obtained from a glucose concentration of 50 g/l, with a glucose utilization of 95.2%. Supplementation with individual vitamins showed that biotin was the most likely factor to be limiting for succinic acid production with spent yeast cell hydrolysate. After supplementing spent yeast cell hydrolysate and 90 g/l of glucose with 150 μg/l of biotin, cell growth increased 32.5%, glucose utilization increased 37.6%, and succinic acid concentration was enhanced 49.0%. As a result, when biotin-supplemented spent yeast cell hydrolysate was used with corn fiber hydrolysate, a succinic acid yield of 67.7% was obtained from 70.3 g/l of total sugar concentration, with a productivity of 0.63 g/(l h). Our results suggest that biotin-supplemented spent yeast cell hydrolysate may be an alternative nitrogen source for the efficient production of succinic acid by A. succinogenes NJ113, using renewable resources. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

Integrated cellulosic enzymes hydrolysis and fermentative advanced yeast bioconversion solution ready for biomass biorefineries

Energy Technology Data Exchange (ETDEWEB)

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

2011-05-04

These are slides from this conference. 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.

Improved vanillin production in baker's yeast through in silico design.

Science.gov (United States)

Brochado, Ana Rita; Matos, Claudia; Møller, Birger L; Hansen, Jørgen; Mortensen, Uffe H; Patil, Kiran Raosaheb

2010-11-08

Vanillin is one of the most widely used flavouring agents, originally obtained from cured seed pods of the vanilla orchid Vanilla planifolia. Currently vanillin is mostly produced via chemical synthesis. A de novo synthetic pathway for heterologous vanillin production from glucose has recently been implemented in baker's yeast, Saccharamyces cerevisiae. In this study we aimed at engineering this vanillin cell factory towards improved productivity and thereby at developing an attractive alternative to chemical synthesis. Expression of a glycosyltransferase from Arabidopsis thaliana in the vanillin producing S. cerevisiae strain served to decrease product toxicity. An in silico metabolic engineering strategy of this vanillin glucoside producing strain was designed using a set of stoichiometric modelling tools applied to the yeast genome-scale metabolic network. Two targets (PDC1 and GDH1) were selected for experimental verification resulting in four engineered strains. Three of the mutants showed up to 1.5 fold higher vanillin β-D-glucoside yield in batch mode, while continuous culture of the Δpdc1 mutant showed a 2-fold productivity improvement. This mutant presented a 5-fold improvement in free vanillin production compared to the previous work on de novo vanillin biosynthesis in baker's yeast. Use of constraints corresponding to different physiological states was found to greatly influence the target predictions given minimization of metabolic adjustment (MOMA) as biological objective function. In vivo verification of the targets, selected based on their predicted metabolic adjustment, successfully led to overproducing strains. Overall, we propose and demonstrate a framework for in silico design and target selection for improving microbial cell factories.

An inventory control model for biomass dependent production systems

International Nuclear Information System (INIS)

Grado, S.C.; Strauss, C.H.

1993-01-01

The financial performance of a biomass dependent production system was critiqued based on the development and validation of an inventory control model. Dynamic programming was used to examine the constraints and capabilities of producing ethanol from various biomass crops. In particular, the model evaluated the plantation, harvest, and manufacturing components of a woody biomass supply system. The optimum wood to ethanol production scheme produced 38 million litres of ethanol in the harvest year, at 13.6 million litre increase over the least optimal policy as demonstrated in the dynamic programming results. The system produced ethanol at a delivered cost of $0.38 L -1 which was consistent with the unit costs from other studies. Nearly 60% of the delivered costs were in ethanol production. The remaining costs were attributed to growing biomass (14%), harvest and shipment of the crop (18%), storage of the raw material and finished product (7%) and open-quotes lost salesclose quotes (2%). Inventory control, in all phases of production, proved to be an important cost consideration throughout the model. The model also analyzed the employment of alternative harvesting policies and the use of different or multiple feedstocks. A comparison between the least cost wood system and an even cut wood system further revealed the benefits of using an inventory control system

Biomass production and carbon storage of Populus ×canadensis ...

African Journals Online (AJOL)

euramericana (Dode) Guinier ex Piccarolo) clone I-214 have good potential for biomass production. The objective of the study was estimation of biomass using allometric equations and estimation of carbon allocation according to tree components.

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.

Integrated carbon analysis of biomass production on fallow agricultural land and product substitution in Sweden - Preliminary results

Energy Technology Data Exchange (ETDEWEB)

Dornburg, Veronika; Eggers, Thies; Gustavsson, Leif [Mid Sweden Univ., Oestersund (Sweden). Ecotechnology

2006-07-15

An important option in the Swedish context to reduce its net emissions of carbon dioxide (CO{sub 2}) is the increased use of biomass for energy and material substitution. On fallow agricultural land additional production of biomass would be possible. We analyse biomass production systems based on Norway spruce, hybrid poplar and willow hybrids and the use of this biomass to replace fossil energy and energy intensive material systems. The highest biomass production potential is for willow in southern Sweden. Fertilisation management of spruce could shorten the rotation lengths by about 17%. The fertilised production of Norway spruce with use of harvested timber for construction and use of remaining woody biomass for heat and power production gives the largest reductions of carbon emissions per hectare under the assumptions made. The use of willow for heat and power and of fertilised spruce for a wood product mix lead to the highest fossil primary energy savings in our scenarios. Spruce cultivations can achieve considerable carbon emission reductions in the long term, but willow and poplar might be a good option when fossil energy savings and carbon emission reductions should be achieved in the short term.

Hydrogen production from biomass by thermochemical recuperative energy conversion

Energy Technology Data Exchange (ETDEWEB)

Fushimi, C.; Araki, K.; Yamaguchi, Y.; Tsutsumi, A. [Tokyo Univ. (Japan). Dept. of Chemical System Engineering

2002-07-01

The authors conducted, using a thermogravimetric reactor, a kinetic study of production of thermochemical recuperative hydrogen from biomass. The four different biomass materials used were: cellulose, lignin, metroxylon stem, and coconut husk. Under both rapid heating and slow heating conditions, the weight changes of the biomass samples during the steam gasification or pyrolysis were measured at 973 Kelvin. Simultaneously, measurements of the evolution rates of low-molecular-weight gas products such as hydrogen, methane, carbon monoxide, and carbon dioxide were taken with the help of a mass spectrometer and a micro gas chromatograph (GC). The steam gasification of char significantly increased the amount of hydrogen and carbon dioxide production. The results also indicated that at higher heating rate, the cold gas efficiency of steam gasification was increased. This can be explained by the suppression of the tar production at lower temperature. 25 refs., 2 tabs., 10 figs.

Furfural production from biomass pretreatment hydrolysate using vapor-releasing reactor system.

Science.gov (United States)

Liu, Lu; Chang, Hou-Min; Jameel, Hasan; Park, Sunkyu

2018-03-01

Biomass hydrolysate from autohydrolysis pretreatment was used for furfural production considering it is in rich of xylose, xylo-oligomers, and other decomposition products from hemicellulose structure. By using the vapor-releasing reactor system, furfural was protected from degradation by separating it from the reaction media. The maximum furfural yield of 73% was achieved at 200 °C for biomass hydrolysate without the use of the catalyst. This is because the presence of organic acids such as acetic acid in hydrolysate functioned as a catalyst. According to the results in this study, biomass hydrolysate with a vapor-releasing system proves to be efficient for furfural production. The biorefinery process which allows the separation of xylose-rich autohydrolysate from other parts from biomass feedstock also improves the overall application of the biomass. Copyright © 2018 Elsevier Ltd. All rights reserved.

Improvement of lipid production by the oleaginous yeast Rhodosporidium toruloides through UV mutagenesis.

Science.gov (United States)

Yamada, Ryosuke; Kashihara, Tomomi; Ogino, Hiroyasu

2017-05-01

Oleaginous yeasts are considered a promising alternative lipid source for biodiesel fuel production. In this study, we attempted to improve the lipid productivity of the oleaginous yeast Rhodosporidium toruloides through UV irradiation mutagenesis and selection based on ethanol and H 2 O 2 tolerance or cerulenin, a fatty acid synthetase inhibitor. Glucose consumption, cell growth, and lipid production of mutants were evaluated. The transcription level of genes involved in lipid production was also evaluated in mutants. The ethanol and H 2 O 2 tolerant strain 8766 2-31M and the cerulenin resistant strain 8766 3-11C were generated by UV mutagenesis. The 8766 2-31M mutant showed a higher lipid production rate, and the 8766 3-11C mutant produced a larger amount of lipid and had a higher lipid production rate than the wild type strain. Transcriptional analysis revealed that, similar to the wild type strain, the ACL1 and GND1 genes were expressed at significantly low levels, whereas IDP1 and ME1 were highly expressed. In conclusion, lipid productivity in the oleaginous yeast R. toruloides was successfully improved via UV mutagenesis and selection. The study also identified target genes for improving lipid productivity through gene recombination.

Anaerobic biotechnological approaches for production of liquid energy carriers from biomass

DEFF Research Database (Denmark)

Karakashev, Dimitar Borisov; Thomsen, Anne Belinda; Angelidaki, Irini

2007-01-01

In recent years, increasing attention has been paid to the use of renewable biomass for energy production. Anaerobic biotechnological approaches for production of liquid energy carriers (ethanol and a mixture of acetone, butanol and ethanol) from biomass can be employed to decrease environmental...... pollution and reduce dependency on fossil fuels. There are two major biological processes that can convert biomass to liquid energy carriers via anaerobic biological breakdown of organic matter: ethanol fermentation and mixed acetone, butanol, ethanol (ABE) fermentation. The specific product formation...

Potential and impacts of renewable energy production from agricultural biomass in Canada

International Nuclear Information System (INIS)

Liu, Tingting; McConkey, Brian; Huffman, Ted; Smith, Stephen; MacGregor, Bob; Yemshanov, Denys; Kulshreshtha, Suren

2014-01-01

Highlights: • This study quantifies the bioenergy production potential in the Canadian agricultural sector. • Two presented scenarios included the mix of market and non-market policy targets and the market-only drivers. • The scenario that used mix of market and policy drivers had the largest impact on the production of bioenergy. • The production of biomass-based ethanol and electricity could cause moderate land use changes up to 0.32 Mha. • Overall, agricultural sector has a considerable potential to generate renewable energy from biomass. - Abstract: Agriculture has the potential to supply considerable amounts of biomass for renewable energy production from dedicated energy crops as well as from crop residues of existing production. Bioenergy production can contribute to the reduction of greenhouse gas (GHG) emissions by using ethanol and biodiesel to displace petroleum-based fuels and through direct burning of biomass to offset coal use for generating electricity. We used the Canadian Economic and Emissions Model for Agriculture to estimate the potential for renewable energy production from biomass, the impacts on agricultural production, land use change and greenhouse gas emissions. We explored two scenarios: the first considers a combination of market incentives and policy mandates (crude oil price of $120 bbl −1 ; carbon offset price of $50 Mg −1 CO 2 equivalent and policy targets of a substitution of 20% of gasoline by biomass-based ethanol; 8% of petroleum diesel by biodiesel and 20% of coal-based electricity by direct biomass combustion), and a second scenario considers only carbon offset market incentives priced at $50 Mg −1 CO 2 equivalent. The results show that under the combination of market incentives and policy mandates scenario, the production of biomass-based ethanol and electricity increases considerably and could potentially cause substantial changes in land use practices. Overall, agriculture has considerable potential to

Biological hydrogen production from biomass by thermophilic bacteria

International Nuclear Information System (INIS)

Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T.; van Niel, E.W.J.

2006-01-01

To meet the reduction of the emission of CO 2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

β-Carotene from Yeasts Enhances Laccase Production of Pleurotus eryngii var. ferulae in Co-culture.

Science.gov (United States)

Guo, Chaolin; Zhao, Liting; Wang, Feng; Lu, Jian; Ding, Zhongyang; Shi, Guiyang

2017-01-01

Laccase is widely used in several industrial applications and co-culture is a common method for enhancing laccase production in submerged fermentation. In this study, the co-culture of four yeasts with Pleurotus eryngii var. ferulae was found to enhance laccase production. An analysis of sterilization temperatures and extraction conditions revealed that the stimulatory compound in yeasts was temperature-sensitive, and that it was fat-soluble. An LC-MS analysis revealed that the possible stimulatory compound for laccase production in the four yeast extracts was β-carotene. Moreover, the addition of 4 mg β-carotene to 150 mL of P. eryngii var. ferulae culture broth improved laccase production by 2.2-fold compared with the control (i.e., a monoculture), and was similar to laccase production in co-culture. In addition, the enhanced laccase production was accompanied by an increase of lac gene transcription, which was 6.2-time higher than the control on the fifth day. Therefore, it was concluded that β-carotene from the co-cultured yeasts enhanced laccase production in P. eryngii var. ferulae , and strains that produce β-carotene could be selected to enhance fungal laccase production in a co-culture. Alternatively, β-carotene or crude extracts of β-carotene could be used to induce high laccase production in large scale.

Ethanol production from biomass: technology and commercialisation status

Energy Technology Data Exchange (ETDEWEB)

Mielenz, J.R.

2001-06-01

Owing to technical improvements in the processes used to produce ethanol from biomass, construction of at least two waste-to-ethanol production plants in the United States is expected to start this year. Although there are a number of robust fermentation microorganisms available, initial pretreatment of the biomass and costly cellulase enzymes remain critical targets for process and cost improvements. A highly efficient, very low-acid pretreatment process is approaching pilot testing, while research on cellulases for ethanol production is expanding at both enzyme and organism level. (Author)

Presence and changes in populations of yeasts on raw and processed poultry products stored at refrigeration temperature.

Science.gov (United States)

Ismail, S A; Deak, T; El-Rahman, H A; Yassien, M A; Beuchat, L R

2000-12-05

A study was undertaken to determine populations and profiles of yeast species on fresh and processed poultry products upon purchase from retail supermarkets and after storage at 5 degrees C until shelf life expiration, and to assess the potential role of these yeasts in product spoilage. Fifty samples representing 15 commercial raw, marinated, smoked, or roasted chicken and turkey products were analyzed. Yeast populations were determined by plating on dichloran rose bengal chloramphenicol (DRBC) agar and tryptone glucose yeast extract (TGY) agar. Proteolytic activity was determined using caseinate and gelatin agars and lipolytic activity was determined on plate count agar supplemented with tributyrin. Populations of aerobic microorganisms were also determined. Initial populations of yeasts (log10 cfu/g) ranged from less than 1 (detection limit) to 2.89, and increased by the expiration date to 0.37-5.06, indicating the presence of psychrotrophic species. Highest initial populations were detected in raw chicken breast, wings, and ground chicken, as well as in turkey necks and legs, whereas roasted chicken and turkey products contained less than 1 log10 cfu/g. During storage, yeast populations increased significantly (P chicken, ground chicken, liver, heart and gizzard, and in ground turkey and turkey sausage. Isolates (152 strains) of yeasts from poultry products consisted of 12 species. Yarrowia lipolytica and Candida zeylanoides were predominant, making up 39 and 26% of the isolates, respectively. Six different species of basidiomycetous yeasts representing 24% of the isolates were identified. Most Y. lipolytica strains showed strong proteolytic and lipolytic activities, whereas C. zeylanoides was weakly lipolytic. Results suggest that yeasts, particularly Y. lipolytica, may play a more prominent role than previously recognized in the spoilage of fresh and processed poultry stored at 5 degrees C.

yeast transformation of Mucor circinelloides Tieghe

African Journals Online (AJOL)

GRACE

2006-05-02

May 2, 2006 ... A nested model analysis of variance of growth data of induced yeast .... Figure 2. Mean biomass and relative growth rates of M. circinelloides cultivated in treatments in ..... Pullman B (ed) Frontiers in Physicochemical Biology.

The Mississippi University Research Consortium for the Utilization of Biomass: Production of Alternative Fuels from Waste Biomass Initiative

Energy Technology Data Exchange (ETDEWEB)

Drs. Mark E. Zapp; Todd French; Lewis Brown; Clifford George; Rafael Hernandez; Marvin Salin (from Mississippie State University); Drs. Huey-Min Hwang, Ken Lee, Yi Zhang; Maria Begonia (from Jackson State University); Drs. Clint Williford; Al Mikell (from the University of Mississippi); Drs. Robert Moore; Roger Hester (from the University of Southern Mississippi).

2009-03-31

The Mississippi Consortium for the Utilization of Biomass was formed via funding from the US Department of Energy's EPSCoR Program, which is administered by the Office of Basic Science. Funding was approved in July of 1999 and received by participating Mississippi institutions by 2000. The project was funded via two 3-year phases of operation (the second phase was awarded based on the high merits observed from the first 3-year phase), with funding ending in 2007. The mission of the Consortium was to promote the utilization of biomass, both cultured and waste derived, for the production of commodity and specialty chemicals. These scientific efforts, although generally basic in nature, are key to the development of future industries within the Southeastern United States. In this proposal, the majority of the efforts performed under the DOE EPSCoR funding were focused primarily toward the production of ethanol from lignocellulosic feedstocks and biogas from waste products. However, some of the individual projects within this program investigated the production of other products from biomass feeds (i.e. acetic acid and biogas) along with materials to facilitate the more efficient production of chemicals from biomass. Mississippi is a leading state in terms of raw biomass production. Its top industries are timber, poultry production, and row crop agriculture. However, for all of its vast amounts of biomass produced on an annual basis, only a small percentage of the biomass is actually industrially produced into products, with the bulk of the biomass being wasted. This situation is actually quite representative of many Southeastern US states. The research and development efforts performed attempted to further develop promising chemical production techniques that use Mississippi biomass feedstocks. The three processes that were the primary areas of interest for ethanol production were syngas fermentation, acid hydrolysis followed by hydrolyzate fermentation, and

Improved vanillin production in baker's yeast through in silico design

Science.gov (United States)

2010-01-01

Background Vanillin is one of the most widely used flavouring agents, originally obtained from cured seed pods of the vanilla orchid Vanilla planifolia. Currently vanillin is mostly produced via chemical synthesis. A de novo synthetic pathway for heterologous vanillin production from glucose has recently been implemented in baker's yeast, Saccharamyces cerevisiae. In this study we aimed at engineering this vanillin cell factory towards improved productivity and thereby at developing an attractive alternative to chemical synthesis. Results Expression of a glycosyltransferase from Arabidopsis thaliana in the vanillin producing S. cerevisiae strain served to decrease product toxicity. An in silico metabolic engineering strategy of this vanillin glucoside producing strain was designed using a set of stoichiometric modelling tools applied to the yeast genome-scale metabolic network. Two targets (PDC1 and GDH1) were selected for experimental verification resulting in four engineered strains. Three of the mutants showed up to 1.5 fold higher vanillin β-D-glucoside yield in batch mode, while continuous culture of the Δpdc1 mutant showed a 2-fold productivity improvement. This mutant presented a 5-fold improvement in free vanillin production compared to the previous work on de novo vanillin biosynthesis in baker's yeast. Conclusion Use of constraints corresponding to different physiological states was found to greatly influence the target predictions given minimization of metabolic adjustment (MOMA) as biological objective function. In vivo verification of the targets, selected based on their predicted metabolic adjustment, successfully led to overproducing strains. Overall, we propose and demonstrate a framework for in silico design and target selection for improving microbial cell factories. PMID:21059201

Improved vanillin production in baker's yeast through in silico design

Directory of Open Access Journals (Sweden)

Hansen Jørgen

2010-11-01

Full Text Available Abstract Background Vanillin is one of the most widely used flavouring agents, originally obtained from cured seed pods of the vanilla orchid Vanilla planifolia. Currently vanillin is mostly produced via chemical synthesis. A de novo synthetic pathway for heterologous vanillin production from glucose has recently been implemented in baker's yeast, Saccharamyces cerevisiae. In this study we aimed at engineering this vanillin cell factory towards improved productivity and thereby at developing an attractive alternative to chemical synthesis. Results Expression of a glycosyltransferase from Arabidopsis thaliana in the vanillin producing S. cerevisiae strain served to decrease product toxicity. An in silico metabolic engineering strategy of this vanillin glucoside producing strain was designed using a set of stoichiometric modelling tools applied to the yeast genome-scale metabolic network. Two targets (PDC1 and GDH1 were selected for experimental verification resulting in four engineered strains. Three of the mutants showed up to 1.5 fold higher vanillin β-D-glucoside yield in batch mode, while continuous culture of the Δpdc1 mutant showed a 2-fold productivity improvement. This mutant presented a 5-fold improvement in free vanillin production compared to the previous work on de novo vanillin biosynthesis in baker's yeast. Conclusion Use of constraints corresponding to different physiological states was found to greatly influence the target predictions given minimization of metabolic adjustment (MOMA as biological objective function. In vivo verification of the targets, selected based on their predicted metabolic adjustment, successfully led to overproducing strains. Overall, we propose and demonstrate a framework for in silico design and target selection for improving microbial cell factories.

PRODUCTION OF NEW BIOMASS/WASTE-CONTAINING SOLID FUELS

Energy Technology Data Exchange (ETDEWEB)

David J. Akers; Glenn A. Shirey; Zalman Zitron; Charles Q. Maney

2001-04-20

CQ Inc. and its team members (ALSTOM Power Inc., Bliss Industries, McFadden Machine Company, and industry advisors from coal-burning utilities, equipment manufacturers, and the pellet fuels industry) addressed the objectives of the Department of Energy and industry to produce economical, new solid fuels from coal, biomass, and waste materials that reduce emissions from coal-fired boilers. This project builds on the team's commercial experience in composite fuels for energy production. The electric utility industry is interested in the use of biomass and wastes as fuel to reduce both emissions and fuel costs. In addition to these benefits, utilities also recognize the business advantage of consuming the waste byproducts of customers both to retain customers and to improve the public image of the industry. Unfortunately, biomass and waste byproducts can be troublesome fuels because of low bulk density, high moisture content, variable composition, handling and feeding problems, and inadequate information about combustion and emissions characteristics. Current methods of co-firing biomass and wastes either use a separate fuel receiving, storage, and boiler feed system, or mass burn the biomass by simply mixing it with coal on the storage pile. For biomass or biomass-containing composite fuels to be extensively used in the U.S., especially in the steam market, a lower cost method of producing these fuels must be developed that includes both moisture reduction and pelletization or agglomeration for necessary fuel density and ease of handling. Further, this method of fuel production must be applicable to a variety of combinations of biomass, wastes, and coal; economically competitive with current fuels; and provide environmental benefits compared with coal. Notable accomplishments from the work performed in Phase I of this project include the development of three standard fuel formulations from mixtures of coal fines, biomass, and waste materials that can be used in

Solid state fermentation (SSF): diversity of applications to valorize waste and biomass.

Science.gov (United States)

Lizardi-Jiménez, M A; Hernández-Martínez, R

2017-05-01

Solid state fermentation is currently used in a range of applications including classical applications, such as enzyme or antibiotic production, recently developed products, such as bioactive compounds and organic acids, new trends regarding bioethanol and biodiesel as sources of alternative energy, and biosurfactant molecules with environmental purposes of valorising unexploited biomass. This work summarizes the diversity of applications of solid state fermentation to valorize biomass regarding alternative energy and environmental purposes. The success of applying solid state fermentation to a specific process is affected by the nature of specific microorganisms and substrates. An exhaustive number of microorganisms able to grow in a solid matrix are presented, including fungus such as Aspergillus or Penicillum for antibiotics, Rhizopus for bioactive compounds, Mortierella for biodiesel to bacteria, Bacillus for biosurfactant production, or yeast for bioethanol.

Cocoa butter-like lipid production ability of non-oleaginous and oleaginous yeasts under nitrogen-limited culture conditions.

Science.gov (United States)

Wei, Yongjun; Siewers, Verena; Nielsen, Jens

2017-05-01

Cocoa butter (CB) extracted from cocoa beans is the main raw material for chocolate production. However, growing chocolate demands and limited CB production has resulted in a shortage of CB supply. CB is mainly composed of three different kinds of triacylglycerols (TAGs), POP (C16:0-C18:1-C16:0), POS (C16:0-C18:1-C18:0), and SOS (C18:0-C18:1-C18:0). The storage lipids of yeasts, mainly TAGs, also contain relative high-level of C16 and C18 fatty acids and might be used as CB-like lipids (CBL). In this study, we cultivated six different yeasts, including one non-oleaginous yeast strain, Saccharomyces cerevisiae CEN.PK113-7D, and five oleaginous yeast strains, Trichosporon oleaginosus DSM11815, Rhodotorula graminis DSM 27356, Lipomyces starkeyi DSM 70296, Rhodosporidium toruloides DSM 70398, and Yarrowia lipolytica CBS 6124, in nitrogen-limited medium and compared their CBL production ability. Under the same growth conditions, we found that TAGs were the main lipids in all six yeasts and that T. oleaginosus can produce more TAGs than the other five yeasts. Less than 3% of the total TAGs were identified as potential SOS in the six yeasts. However, T. oleaginosus produced 27.8% potential POP and POS at levels of 378 mg TAGs/g dry cell weight, hinting that this yeast may have potential as a CBL production host after further metabolic engineering in future.

Process Design and Economics for the Conversion of Algal Biomass to Biofuels: Algal Biomass Fractionation to Lipid-and Carbohydrate-Derived Fuel Products

Energy Technology Data Exchange (ETDEWEB)

None

2014-09-11

The U.S. Department of Energy (DOE) promotes the production of a range of liquid fuels and fuel blendstocks from biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass production, conversion, and sustainability. As part of its involvement in this program, the National Renewable Energy Laboratory (NREL) investigates the conceptual production economics of these fuels. This includes fuel pathways from lignocellulosic (terrestrial) biomass, as well as from algal (aquatic) biomass systems.

Biomass production and utilisation. Policy implications for LDCs

International Nuclear Information System (INIS)

Davidson, O.

1997-01-01

The importance of biomass in the energy sector of LDCs and in Africa in particular is illustrated so as to provide the background to the policy importance on the production and use of this energy source. The main areas for policy attention discussed are: biomass for power generation, biomass use in the transport sector, urban energy supply and the interactions with agricultural policies. The roles of the major institutions the government, private sector institutions, educational institutions and non-governmental organizations are identified. It is concluded that with the necessary policy shift that is being advocated, biomass can contribute to a more equitable supply of high quality and efficient energy services in the future of African countries. (K.A.)

BioRefine. New biomass products programme 2007-2012. Final report

Energy Technology Data Exchange (ETDEWEB)

Makinen, T. (ed.) [VTT Technical Research Centre of Finland, Espoo (Finland); Alakangas, E.; Holviala, N. (eds.) [VTT Technical Research Centre of Finland, Jyvaskyla (Finland)

2012-07-01

The focal areas of the BioRefine programme have been business development, raw materials, and product lines. The key issue in the programme has been the development of business opportunities. The other two programme areas - raw materials and product lines, including technologies and services - have always been viewed from the perspective of short, medium or long-term business activities.The programme has organised four calls for research projects. The focus of the first call was on biomass-based fuels for transport (in the autumn 2007), the second one focused on other biomass-based products like chemicals and materials (in the spring 2008), and the third one on new biomass sources and waste-based biomass, and research supporting the business development of SME companies (early in 2010). In the last call in the spring 2011, project proposals were expected to focus on the following areas: new innovative and multidisciplinary research initiatives related to biomass utilisation, small distributed biorefinery concepts, efficient and sustainable utilisation of biomass raw materials in new integrated solutions for biorefining, and new integrated solutions for the efficient utilisation of sidestreams in the biorefining value chain or in its parts. Unlike research organizations, companies have been able to apply for funding continuously from Tekes.

Production and characterization of bio-oil from catalytic biomass pyrolysis

Directory of Open Access Journals (Sweden)

Antonakou Eleni V.

2006-01-01

Full Text Available Biomass flash pyrolysis is a very promising thermochemical process for the production of bio-fuels and/or chemicals. However, large-scale applications are still under careful consideration, because of the high bio-liquid upgrading cost. In this paper the production of bio-liquids from biomass flash pyrolysis in a single stage catalytic process is being investigated using a novel once through fluid bed reactor. This biomass pyrolysis unit was constructed in Chemical Process Engineering Research Institute and comprises of a catalyst regenerator, a biomass-vibrating hopper, a fluidization reactor (that consists of an injector and a riser reactor, a product stripper along with a hot cyclone and a filter housing and finally a product condensation/recovery section. The unit can process up to 20 g/min. of biomass (50-800 mm and can circulate up to 300 g/min. of catalyst or inert material. The experiments performed in the pilot plant showed that the unit operates without problems and with satisfactory mass balances in a wide range of experimental conditions both in the absence and presence of catalyst. With the incorporation of an FCC catalyst in the pyrolysis, the physical properties of the bio-oil produced changed, while more stable bio-oil was produced. .

Optimal mode of operation for biomass production

NARCIS (Netherlands)

Betlem, Ben H.L.; Roffel, Brian; Mulder, P.

2002-01-01

The rate of biomass production is optimised for a predefined feed exhaustion using the residue ratio as a degree of freedom. Three modes of operation are considered: continuous, repeated batch, and repeated fed-batch operation. By means of the Production Curve, the transition points of the optimal

Direct production of fractionated and upgraded hydrocarbon fuels from biomass

Science.gov (United States)

Felix, Larry G.; Linck, Martin B.; Marker, Terry L.; Roberts, Michael J.

2014-08-26

Multistage processing of biomass to produce at least two separate fungible fuel streams, one dominated by gasoline boiling-point range liquids and the other by diesel boiling-point range liquids. The processing involves hydrotreating the biomass to produce a hydrotreatment product including a deoxygenated hydrocarbon product of gasoline and diesel boiling materials, followed by separating each of the gasoline and diesel boiling materials from the hydrotreatment product and each other.

Assessment of potential biomass energy production in China towards 2030 and 2050

OpenAIRE

Zhao, Guangling

2016-01-01

The objective of this paper is to provide a more detailed picture of potential biomass energy production in the Chinese energy system towards 2030 and 2050. Biomass for bioenergy feedstocks comes from five sources, which are agricultural crop residues, forest residues and industrial wood waste, energy crops and woody crops, animal manure, and municipal solid waste. The potential biomass production is predicted based on the resource availability. In the process of identifying biomass resources...

Characterization of biofilm-forming cyanobacteria for biomass and lipid production.

Science.gov (United States)

Bruno, L; Di Pippo, F; Antonaroli, S; Gismondi, A; Valentini, C; Albertano, P

2012-11-01

This work reports on one of the first attempts to use biofilm-forming cyanobacteria for biomass and lipid production. Three isolates of filamentous cyanobacteria were obtained from biofilms at different Italian sites and characterized by a polyphasic approach, involving microscopic observations, ecology and genetic diversity (studying the 16S rRNA gene). The isolates were grown in batch systems and in a semi-continuous flow incubator, specifically designed for biofilms development. Culture system affected biomass and lipid production, but did not influence the fatty acid profile. The composition of fatty acids was mainly palmitic acid (>50%) and less amounts of other saturated and monounsaturated fatty acids. Only two isolates contained two polyunsaturated fatty acids. Data obtained from the flow-lane incubator system would support a more economical and sustainable use of the benthic micro-organisms for biomass production. The produced lipids contained fatty acids suitable for a high-quality biodiesel production, showing high proportions of saturated and monounsaturated fatty acids. Data seem promising when taking into account the savings in cost and time derived from easy procedures for biomass harvesting, especially when being able to obtain the co-production of other valuable by-products. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Biosynthesis of fluorescent CdS nanocrystals with semiconductor properties: Comparison of microbial and plant production systems.

Science.gov (United States)

Al-Shalabi, Zahwa; Doran, Pauline M

2016-04-10

This study investigated fission yeast (Schizosaccharomyces pombe) and hairy roots of tomato (Solanum lycopersicum) as in vitro production vehicles for biological synthesis of CdS quantum dots. Cd added during the mid-growth phase of the cultures was detoxified within the biomass into inorganic sulphide-containing complexes with the quantum confinement properties of semiconductor nanocrystals. Significant differences were found between the two host systems in terms of nanoparticle production kinetics, yield and quality. The much slower growth rate of hairy roots compared with yeast is a disadvantage for commercial scaled-up production. Nanoparticle extraction from the biomass was less effective for the roots: 19% of the Cd present in the hairy roots was recovered after extraction compared with 34% for the yeast. The overall yield of CdS quantum dots was also lower for the roots: relative to the amount of Cd taken up into the biomass, 8.5% was recovered in yeast gel filtration fractions exhibiting quantum dot properties whereas the result for hairy roots was only 0.99%. Yeast-produced CdS crystallites were somewhat smaller with diameters of approximately 2-6 nm compared with those of 4-10nm obtained from the roots. The average ratio of inorganic sulphide to Cd for the purified and size-fractionated particles was 0.44 for the yeast and 1.6 for the hairy roots. Despite the limitations associated with hairy roots in terms of culture kinetics and product yield, this system produced CdS nanoparticles with enhanced photostability and 3.7-13-fold higher fluorescence quantum efficiency compared with those generated by yeast. This work demonstrates that the choice of cellular host can have a significant effect on nanoparticle functional properties as well as on the bioprocessing aspects of biological quantum dot synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

Agroecology of Novel Annual and Perennial Crops for Biomass Production

DEFF Research Database (Denmark)

Manevski, Kiril; Jørgensen, Uffe; Lærke, Poul Erik

The agroecological potential of many crops under sustainable intensification has not been investigated. This study investigates such potential for novel annual and perennial crops grown for biomass production.......The agroecological potential of many crops under sustainable intensification has not been investigated. This study investigates such potential for novel annual and perennial crops grown for biomass production....

Advanced biomass science and technology for bio-based products: proceedings

Science.gov (United States)

Chung Hse; Zehui Jiang; Mon-Lin Kuo

2009-01-01

This book was developed from the proceedings of the Advanced Biomass Science and Technology for Bio-Based Products Symposium held in Beijing, China, May 23-25, 2007. The symposium was designed to provide a forum for researchers, producers, and consumers of biomass and bio-based products; to exchange information and ideas; and to stimulate new research and...

Biomass and pigments production in photosynthetic bacteria wastewater treatment: effects of light sources.

Science.gov (United States)

Zhou, Qin; Zhang, Panyue; Zhang, Guangming

2015-03-01

This study is aimed at enhancing biomass and pigments production together with pollution removal in photosynthetic bacteria (PSB) wastewater treatment via different light sources. Red, yellow, blue, white LED and incandescent lamp were used. Results showed different light sources had great effects on the PSB. PSB had the highest biomass production, COD removal and biomass yield with red LED. The corresponding biomass, COD removal and biomass yield reached 2580 mg/L, 88.6% and 0.49 mg-biomass/mg-COD-removal, respectively. The hydraulic retention time of wastewater treatment could be shortened to 72 h with red LED. Mechanism analysis showed higher ATP was produced with red LED than others. Light sources could significantly affect the pigments production. The pigments productions were greatly higher with LED than incandescent lamp. Yellow LED had the highest pigments production while red LED produced the highest carotenoid/bacteriochlorophyll ratio. Considering both efficiency and energy cost, red LED was the optimal light source. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simultaneous cell growth and ethanol production from cellulose by an engineered yeast consortium displaying a functional mini-cellulosome

Directory of Open Access Journals (Sweden)

Madan Bhawna

2011-11-01

Full Text Available Abstract Background The recalcitrant nature of cellulosic materials and the high cost of enzymes required for efficient hydrolysis are the major impeding steps to their practical usage for ethanol production. Ideally, a recombinant microorganism, possessing the capability to utilize cellulose for simultaneous growth and ethanol production, is of great interest. We have reported recently the use of a yeast consortium for the functional presentation of a mini-cellulosome structure onto the yeast surface by exploiting the specific interaction of different cohesin-dockerin pairs. In this study, we engineered a yeast consortium capable of displaying a functional mini-cellulosome for the simultaneous growth and ethanol production on phosphoric acid swollen cellulose (PASC. Results A yeast consortium composed of four different populations was engineered to display a functional mini-cellulosome containing an endoglucanase, an exoglucanase and a β-glucosidase. The resulting consortium was demonstrated to utilize PASC for growth and ethanol production. The final ethanol production of 1.25 g/L corresponded to 87% of the theoretical value and was 3-fold higher than a similar yeast consortium secreting only the three cellulases. Quantitative PCR was used to enumerate the dynamics of each individual yeast population for the two consortia. Results indicated that the slight difference in cell growth cannot explain the 3-fold increase in PASC hydrolysis and ethanol production. Instead, the substantial increase in ethanol production is consistent with the reported synergistic effect on cellulose hydrolysis using the displayed mini-cellulosome. Conclusions This report represents a significant step towards the goal of cellulosic ethanol production. This engineered yeast consortium displaying a functional mini-cellulosome demonstrated not only the ability to grow on the released sugars from PASC but also a 3-fold higher ethanol production than a similar yeast

Maintaining environmental quality while expanding biomass production: Sub-regional U.S. policy simulations

International Nuclear Information System (INIS)

Egbendewe-Mondzozo, Aklesso; Swinton, Scott M.; Izaurralde, R. César; Manowitz, David H.; Zhang, Xuesong

2013-01-01

This paper evaluates environmental policy effects on ligno-cellulosic biomass production and environmental outcomes using an integrated bioeconomic optimization model. The environmental policy integrated climate (EPIC) model is used to simulate crop yields and environmental indicators in current and future potential bioenergy cropping systems based on weather, topographic and soil data. The crop yield and environmental outcome parameters from EPIC are combined with biomass transport costs and economic parameters in a representative farmer profit-maximizing mathematical optimization model. The model is used to predict the impact of alternative policies on biomass production and environmental outcomes. We find that without environmental policy, rising biomass prices initially trigger production of annual crop residues, resulting in increased greenhouse gas emissions, soil erosion, and nutrient losses to surface and ground water. At higher biomass prices, perennial bioenergy crops replace annual crop residues as biomass sources, resulting in lower environmental impacts. Simulations of three environmental policies namely a carbon price, a no-till area subsidy, and a fertilizer tax reveal that only the carbon price policy systematically mitigates environmental impacts. The fertilizer tax is ineffectual and too costly to farmers. The no-till subsidy is effective only at low biomass prices and is too costly to government. - Highlights: ► Bioeconomic optimization model predicts how biomass production affects environment. ► Rising biomass production could impair climate and water quality. ► Environmental protection policies compared as biomass supply grows. ► Carbon price protects the environment cost-effectively as biomass supply expands

Techno-economic analysis of ammonia production via integrated biomass gasification

International Nuclear Information System (INIS)

Andersson, Jim; Lundgren, Joakim

2014-01-01

Highlights: • Techno-economic results regarding biomass-based ammonia production systems. • Integration of an ammonia production process in a pulp and paper mill. • Integrated ammonia production gains higher system efficiency than stand-alone production. • The economics of an integrated production system is improved compared to stand-alone production. - Abstract: Ammonia (NH 3 ) can be produced by synthesis of nitrogen and hydrogen in the Haber–Bosch process, where the economic challenge is the hydrogen production. Currently, substantial amounts of greenhouse gases are emitted from the ammonia industry since the hydrogen production is almost exclusively based on fossil feedstocks. Hydrogen produced via gasification of lignocellulosic biomass is a more environmentally friendly alternative, but the economic performance is critical. The main objective of this work was to perform a techno-economic evaluation of ammonia production via integrated biomass gasification in an existing pulp and paper mill. The results were compared with a stand-alone production case to find potential technical and economic benefits deriving from the integration. The biomass gasifier and the subsequent NH 3 production were modelled using the commercial software Aspen Plus. A process integration model based on Mixed Integer Linear Programming (MILP) was used to analyze the effects on the overall energy system of the pulp mill. Important modelling constraints were to maintain the pulp production and the steam balance of the mill. The results showed that the process economics and energy performance are favourable for the integrated case compared to stand-alone production. The main conclusion was however that a rather high NH 3 selling price is required to make both production cases economically feasible

Production of xylitol from biomass using an inhibitor-tolerant fungal strain

Science.gov (United States)

Inhibitory compounds arising from physical–chemical pretreatment of biomass feedstock can interfere with fermentation of biomass sugars to product. A fungus, Coniochaeta ligniaria NRRL30616 improves fermentability of biomass sugars by metabolizing a variety of microbial inhibitors including furan al...

Ethanol production potential of local yeast strains isolated from ripe ...

African Journals Online (AJOL)

STORAGESEVER

2008-05-16

May 16, 2008 ... ... of these studies, the preferred candidate for industrial production of ethanol ... The yeast strains were isolated using the method of Ameh et al. (1989), on ... gas in the Durham tube during the incubation period. Fermentation ...

Selection of culture medium and conditions for the production of ...

African Journals Online (AJOL)

oyaide

2013-05-15

May 15, 2013 ... improving the productivity and economical benefits in livestock production ... was to improve the yeast biomass production measured as dry cell ... the total livestock population in India was 1708 Million ... Media for culture maintenance and optimization .... which is very economical and efficient source for the.

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

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

Availability of biomass for energy production. GRAIN: Global Restrictions on biomass Availability for Import to the Netherlands

International Nuclear Information System (INIS)

Lysen, E.H.

2000-08-01

The report includes reports of activities that were carried out within the GRAIN project. This evaluation shows that the (technical) potential contribution of bio-energy to the future world's energy supply could be very large. In theory, energy farming on current agricultural land could contribute over 800 EJ, without jeopardising the world's food supply. Use of degraded lands may add another 150 EJ, although this contribution will largely come from crops with a low productivity. The growing demand for bio-materials may require a biomass input equivalent to 20-50 EJ, which must be grown on plantations when existing forests are not able to supply this growing demand. Organic wastes and residues could possibly supply another 40-170 EJ, with uncertain contributions from forest residues and potentially a very significant role for organic waste, especially when bio-materials are used on a larger scale. In total, the upper limit of the bio-energy potential could be over 1000 EJ per year. This is considerably more than the current global energy use of 400 EJ. However, this contribution is by no means guaranteed: crucial factors determining biomass availability for energy are: (1) Population growth and economic development; (2) The efficiency and productivity of food production systems that must be adopted worldwide and the rate of their deployment in particular in developing countries; (3) Feasibility of the use of marginal/degraded lands; (4) Productivity of forests and sustainable harvest levels; (5) The (increased) utilisation of bio-materials. Major transitions are required to exploit this bio-energy potential. It is uncertain to what extent such transitions are feasible. Depending on the factors mentioned above, the bio-energy potential could be very low as well. At regional/local level the possibilities and potential consequences of biomass production and use can vary strongly, but the insights in possible consequences are fairly limited up to now. Bio-energy offers

Single Cell Oil Production from Hydrolysates of Inulin by a Newly Isolated Yeast Papiliotrema laurentii AM113 for Biodiesel Making.

Science.gov (United States)

Wang, Guangyuan; Liu, Lin; Liang, Wenxing

2018-01-01

Microbial oils are among the most attractive alternative feedstocks for biodiesel production. In this study, a newly isolated yeast strain, AM113 of Papiliotrema laurentii, was identified as a potential lipid producer, which could accumulate a large amount of intracellular lipids from hydrolysates of inulin. P. laurentii AM113 was able to produce 54.6% (w/w) of intracellular oil in its cells and 18.2 g/l of dry cell mass in a fed-batch fermentation. The yields of lipid and biomass were 0.14 and 0.25 g per gram of consumed sugar, respectively. The lipid productivity was 0.092 g of oil per hour. Compositions of the fatty acids produced were C 14:0 (0.9%), C 16:0 (10.8%), C 16:1 (9.7%), C 18:0 (6.5%), C 18:1 (60.3%), and C 18:2 (11.8%). Biodiesel obtained from the extracted lipids could be burnt well. This study not only provides a promising candidate for single cell oil production, but will also probably facilitate more efficient biodiesel production.

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.

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

Urea production by yeasts other than Saccharomyces in food fermentation

NARCIS (Netherlands)

Wu, Qun; Cui, Kaixiang; Lin, Jianchun; Zhu, Yang; Xu, Yan

2017-01-01

Urea is an important intermediate in the synthesis of carcinogenic ethyl carbamate in various food fermentations. Identifying urea-producing microorganisms can help control or reduce ethyl carbamate production. Using Chinese liquor fermentation as a model system, we identified the yeasts responsible

Engineering yeast for high-level production of stilbenoid antioxidants

DEFF Research Database (Denmark)

Li, Mingji; Schneider, Konstantin; Kristensen, Mette

2016-01-01

engineered the yeast Saccharomyces cerevisiae for production of stilbenoids on a simple mineral medium typically used for industrial production. We applied a pull-push-block strain engineering strategy that included overexpression of the resveratrol biosynthesis pathway, optimization of the electron transfer...... to the cytochrome P450 monooxygenase, increase of the precursors supply, and decrease of the pathway intermediates degradation. Fed-batch fermentation of the final strain resulted in a final titer of 800 mg l(-1) resveratrol, which is by far the highest titer reported to date for production of resveratrol from...

Development of a yeast cell factory for production of aromatic products

DEFF Research Database (Denmark)

Rodriguez Prado, Edith Angelica; Kildegaard, Kanchana Rueksomtawin; Li, Mingji

2014-01-01

There is much interest in aromatic chemicals in the chemical industry as these can be used for production of dyes, anti-oxidants, nutraceuticals and food ingredients. Yeast is a widely used cell factory and it is particularly well suited for production of aromatic chemicals via complex biosynthetic...... routes involving P450 enzymes. In Saccharomyces cerevisiae the fluxes towards aromatic acids (L-tryptophan, L-tyrosine and L-phenylalanine) are strictly controlled on transcriptional and kinetic levels and therefore are difficult to manipulate. We engineered S. cerevisiae for increased production...... of aromatic compounds by eliminating degradation, up-regulating the key enzyme encoding genes, and removing feed-back inhibition in the pathway. In order to test the strain performance we overexpressed heterologous pathway for coumaric acid production. We obtained 4-fold higher concentrations of coumaric acid...

Techno Economic Analysis of Hydrogen Production by gasification of biomass

Energy Technology Data Exchange (ETDEWEB)

Francis Lau

2002-12-01

Biomass represents a large potential feedstock resource for environmentally clean processes that produce power or chemicals. It lends itself to both biological and thermal conversion processes and both options are currently being explored. Hydrogen can be produced in a variety of ways. The majority of the hydrogen produced in this country is produced through natural gas reforming and is used as chemical feedstock in refinery operations. In this report we will examine the production of hydrogen by gasification of biomass. Biomass is defined as organic matter that is available on a renewable basis through natural processes or as a by-product of processes that use renewable resources. The majority of biomass is used in combustion processes, in mills that use the renewable resources, to produce electricity for end-use product generation. This report will explore the use of hydrogen as a fuel derived from gasification of three candidate biomass feedstocks: bagasse, switchgrass, and a nutshell mix that consists of 40% almond nutshell, 40% almond prunings, and 20% walnut shell. In this report, an assessment of the technical and economic potential of producing hydrogen from biomass gasification is analyzed. The resource base was assessed to determine a process scale from feedstock costs and availability. Solids handling systems were researched. A GTI proprietary gasifier model was used in combination with a Hysys(reg. sign) design and simulation program to determine the amount of hydrogen that can be produced from each candidate biomass feed. Cost estimations were developed and government programs and incentives were analyzed. Finally, the barriers to the production and commercialization of hydrogen from biomass were determined. The end-use of the hydrogen produced from this system is small PEM fuel cells for automobiles. Pyrolysis of biomass was also considered. Pyrolysis is a reaction in which biomass or coal is partially vaporized by heating. Gasification is a more

Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models.

Science.gov (United States)

Pfohl-Leszkowicz, A; Hadjeba-Medjdoub, K; Ballet, N; Schrickx, J; Fink-Gremmels, J

2015-01-01

The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease

Quantifying biomass production in crops grown for energy

Energy Technology Data Exchange (ETDEWEB)

Bullard, M J; Christian, D; Wilkins, C

1997-12-31

One estimate suggests that continued CAP (Common Agricultural Policy) reform may lead to as much as 2 million hectares of land set aside from arable production by the year 2020 in the UK alone, with 20 million hectares in the EU in total. Set-aside currently occupies more than 500,000 hectares in the UK. Set-aside land is providing more opportunities for non-food crops, for example fuel crops, which provide biomass for energy. Whilst any crop species will produce biomass which can be burnt to produce energy, arable crops were not developed with this in mind but rather a specific harvestable commodity, e.g. grain, and therefore the total harvestable commodity is seldom maximised. The characteristics of an ideal fuel crop have been identified as: dry harvested material for efficient combustion; perennial growth to minimise establishment costs and lengthen the growing season; good disease resistance; efficient conversion of solar radiation to biomass energy; efficient use of nitrogen fertiliser (where required) and water; and yield close to the theoretical maximum. Miscanthus, a genus of Oriental and African C4 perennial grasses, has been identified as possessing the above characteristics. There may be other species, which, if not yielding quite as much biomass, have other characteristics of merit. This has led to the need to identify inherently productive species which are adapted to the UK, and to validate the productivity of species which have already been 'discovered'. (author)

Quantifying biomass production in crops grown for energy

Energy Technology Data Exchange (ETDEWEB)

Bullard, M.J.; Christian, D.; Wilkins, C.

1996-12-31

One estimate suggests that continued CAP (Common Agricultural Policy) reform may lead to as much as 2 million hectares of land set aside from arable production by the year 2020 in the UK alone, with 20 million hectares in the EU in total. Set-aside currently occupies more than 500,000 hectares in the UK. Set-aside land is providing more opportunities for non-food crops, for example fuel crops, which provide biomass for energy. Whilst any crop species will produce biomass which can be burnt to produce energy, arable crops were not developed with this in mind but rather a specific harvestable commodity, e.g. grain, and therefore the total harvestable commodity is seldom maximised. The characteristics of an ideal fuel crop have been identified as: dry harvested material for efficient combustion; perennial growth to minimise establishment costs and lengthen the growing season; good disease resistance; efficient conversion of solar radiation to biomass energy; efficient use of nitrogen fertiliser (where required) and water; and yield close to the theoretical maximum. Miscanthus, a genus of Oriental and African C4 perennial grasses, has been identified as possessing the above characteristics. There may be other species, which, if not yielding quite as much biomass, have other characteristics of merit. This has led to the need to identify inherently productive species which are adapted to the UK, and to validate the productivity of species which have already been 'discovered'. (author)

Effects of spent craft brewers’ yeast on fermentation and methane production by rumen microorganisms

Science.gov (United States)

Saccharomyces cerevisiae is a key component of beer brewing and a major by-product. The leftover, spent brewers’ yeast, from large breweries has been used for some time as a protein supplement in cattle, however the possible advantages of spent yeast from smaller craft breweries, containing much hig...

Production of fungal biomass protein using microfungi from winery wastewater treatment.

Science.gov (United States)

Zhang, Zhan Ying; Jin, Bo; Bai, Zhi Hui; Wang, Xiao Yi

2008-06-01

This study was carried out to investigate the production of fungal biomass protein (FBP) in treatment of winery wastewater using microfungi. Three fungal strains, Trichoderma viride WEBL0702, Aspergillus niger WEBL0901 and Aspergillus oryzae WEBL0401, were selected in terms of microbial capability for FBP production and COD reduction. T. viride appeared to be the best strain for FBP production due to high productivity and less nitrogen requirement. More than 5 g/L of fungal biomass was produced in shake fermentation using T. viride without nitrogen addition, and by A. oryzae and A. niger with addition of 0.5-1.0 g/L (NH4)2SO4. The FBP production process corresponded to 84-90% COD reduction of winery wastewater. Fungal biomass contained approximately 36% protein produced by two Aspergillus strains, while biomass produced by T. viride consisted of 19.8% protein. Kinetic study indicated that maximum fungal cell growth could be achieved in 24h for T. viride and 48 h for A. oryzae and A. niger. Current results indicated that it could be feasible to develop a biotechnological treatment process integrated with FBP production from the winery waste streams.

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.

Catalytic Production of Ethanol from Biomass-Derived Synthesis Gas

Energy Technology Data Exchange (ETDEWEB)

Trewyn, Brian G. [Colorado School of Mines, Golden, CO (United States); Smith, Ryan G. [Iowa State Univ., Ames, IA (United States)

2016-06-01

Heterogeneous catalysts have been developed for the conversion of biomass-derived synthetic gas (syngas) to ethanol. The objectives of this project were to develop a clean synthesis gas from biomass and develop robust catalysts with high selectivity and lifetime for C₂ oxygenate production from biomass-derived syngas and surrogate syngas. During the timeframe for this project, we have made research progress on the four tasks: (1) Produce clean bio-oil generated from biomass, such as corn stover or switchgrass, by using fast pyrolysis system, (2) Produce clean, high pressure synthetic gas (syngas: carbon monoxide, CO, and hydrogen, H₂) from bio-oil generated from biomass by gasification, (3) Develop and characterize mesoporous mixed oxide-supported metal catalysts for the selective production of ethanol and other alcohols, such as butanol, from synthesis gas, and (4) Design and build a laboratory scale synthesis gas to ethanol reactor system evaluation of the process. In this final report, detailed explanations of the research challenges associated with this project are given. Progress of the syngas production from various biomass feedstocks and catalyst synthesis for upgrading the syngas to C₂-oxygenates is included. Reaction properties of the catalyst systems under different reaction conditions and different reactor set-ups are also presented and discussed. Specifically, the development and application of mesoporous silica and mesoporous carbon supports with rhodium nanoparticle catalysts and rhodium nanoparticle with manganese catalysts are described along with the significant material characterizations we completed. In addition to the synthesis and characterization, we described the activity and selectivity of catalysts in our micro-tubular reactor (small scale) and fixed bed reactor (larger scale). After years of hard work, we are proud of the work done on this project, and do believe that this work will provide a solid

Future production and utilisation of biomass in Sweden: potentials and CO2 mitigation

International Nuclear Information System (INIS)

Boerjesson, P.; Gustavsson, L.; Christersson, L.; Linder, S.

1997-01-01

Swedish biomass production potential could be increased significantly if new production methods, such as optimised fertilisation, were to be used. Optimised fertilisation on 25% of Swedish forest land and the use of stem wood could almost double the biomass potential from forestry compared with no fertilisation, as both logging residues and large quantities of excess stem wood not needed for industrial purposes could be used for energy purposes. Together with energy crops and straw from agriculture, the total Swedish biomass potential would be about 230 TWh/yr or half the current Swedish energy supply if the demand for stem wood for building and industrial purposes were the same as today. The new production methods are assumed not to cause any significant negative impact on the local environment. The cost of utilising stem wood produced with optimised fertilisation for energy purposes has not been analysed and needs further investigation. Besides replacing fossil fuels and, thus, reducing current Swedish CO 2 emissions by about 65%, this amount of biomass is enough to produce electricity equivalent to 20% of current power production. Biomass-based electricity is produced preferably through co-generation using district heating systems in densely populated regions, and pulp industries in forest regions. Alcohols for transportation and stand-alone power production are preferably produced in less densely populated regions with excess biomass. A high intensity in biomass production would reduce biomass transportation demands. There are uncertainties regarding the future demand for stem wood for building and industrial purposes, the amount of arable land available for energy crop production and future yields. These factors will influence Swedish biomass potential and earlier estimates of the potential vary from 15 to 125 TWh/yr. (author)

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.

Production of ethanol from cassava pulp via fermentation with a surface-engineered yeast strain displaying glucoamylase

Energy Technology Data Exchange (ETDEWEB)

Kosugi, Akihiko; Murata, Yoshinori; Arai, Takamitsu; Mori, Yutaka [Post-harvest Science and Technology Division, Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686 (Japan); Kondo, Akihiko [Department of Chemical Science and Engineering, Faculty of Engineering, Kobe University, Nada-ku, Kobe, 657-8501 (Japan); Ueda, Mitsuyoshi [Department of Applied Biochemistry, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Vaithanomsat, Pilanee; Thanapase, Warunee [Nanotechnology and Biotechnology Division, Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI), Kasetsart University, 50 Chatuchak, Ladyao, Bangkok 10900 (Thailand)

2009-05-15

Cassava (Manihot esculenta Crantz) pulp, produced in large amounts as a by-product of starch manufacturing, is a major biomass resource in Southeast Asian countries. It contains abundant starch (approximately 60%) and cellulose fiber (approximately 20%). To effectively utilize the cassava pulp, an attempt was made to convert its components to ethanol using a sake-brewing yeast displaying glucoamylase on the cell surface. Saccharomyces cerevisiae Kyokai no. 7 (strain K7) displaying Rhizopus oryzae glucoamylase, designated strain K7G, was constructed using the C-terminal-half region of {alpha}-agglutinin. A sample of cassava pulp was pretreated with a hydrothermal reaction (140 C for 1 h), followed by treatment with a Trichoderma reesei cellulase to hydrolyze the cellulose in the sample. The K7G strain fermented starch and glucose in pretreated samples without addition of amylolytic enzymes, and produced ethanol in 91% and 80% of theoretical yield from 5% and 10% cassava pulp, respectively. (author)

Does species richness affect fine root biomass and production in young forest plantations?

Science.gov (United States)

Domisch, Timo; Finér, Leena; Dawud, Seid Muhie; Vesterdal, Lars; Raulund-Rasmussen, Karsten

2015-02-01

Tree species diversity has been reported to increase forest ecosystem above-ground biomass and productivity, but little is known about below-ground biomass and production in diverse mixed forests compared to single-species forests. For testing whether species richness increases below-ground biomass and production and thus complementarity between forest tree species in young stands, we determined fine root biomass and production of trees and ground vegetation in two experimental plantations representing gradients in tree species richness. Additionally, we measured tree fine root length and determined species composition from fine root biomass samples with the near-infrared reflectance spectroscopy method. We did not observe higher biomass or production in mixed stands compared to monocultures. Neither did we observe any differences in tree root length or fine root turnover. One reason for this could be that these stands were still young, and canopy closure had not always taken place, i.e. a situation where above- or below-ground competition did not yet exist. Another reason could be that the rooting traits of the tree species did not differ sufficiently to support niche differentiation. Our results suggested that functional group identity (i.e. conifers vs. broadleaved species) can be more important for below-ground biomass and production than the species richness itself, as conifers seemed to be more competitive in colonising the soil volume, compared to broadleaved species.

Biosurfactants production by yeasts using soybean oil and glycerol as low cost substrate.

Science.gov (United States)

Accorsini, Fábio Raphael; Mutton, Márcia Justino Rossini; Lemos, Eliana Gertrudes Macedo; Benincasa, Maria

2012-01-01

Biosurfactants are bioactive agents that can be produced by many different microorganisms. Among those, special attention is given to yeasts, since they can produce many types of biosurfactants in large scale, using several kinds of substrates, justifying its use for industrial production of those products. For this production to be economically viable, the use of residual carbon sources is recommended. The present study isolated yeasts from soil contaminated with petroleum oil hydrocarbons and assessed their capacity for producing biosurfactants in low cost substrates. From a microbial consortium enriched, seven yeasts were isolated, all showing potential for producing biosurfactants in soybean oil. The isolate LBPF 3, characterized as Candida antarctica, obtained the highest levels of production - with a final production of 13.86 g/L. The isolate LBPF 9, using glycerol carbon source, obtained the highest reduction in surface tension in the growth medium: approximately 43% of reduction after 24 hours of incubation. The products obtained by the isolates presented surfactant activity, which reduced water surface tension to values that varied from 34 mN/m, obtained from the product of isolates LBPF 3 and 16 LBPF 7 (respectively characterized as Candida antarctica and Candida albicans) to 43 mN/m from the isolate LPPF 9, using glycerol as substrate. The assessed isolates all showed potential for the production of biosurfactants in conventional sources of carbon as well as in agroindustrial residue, especially in glycerol.

Biosurfactants production by yeasts using soybean oil and glycerol as low cost substrate

Directory of Open Access Journals (Sweden)

Fábio Raphael Accorsini

2012-03-01

Full Text Available Biosurfactants are bioactive agents that can be produced by many different microorganisms. Among those, special attention is given to yeasts, since they can produce many types of biosurfactants in large scale, using several kinds of substrates, justifying its use for industrial production of those products. For this production to be economically viable, the use of residual carbon sources is recommended. The present study isolated yeasts from soil contaminated with petroleum oil hydrocarbons and assessed their capacity for producing biosurfactants in low cost substrates. From a microbial consortium enriched, seven yeasts were isolated, all showing potential for producing biosurfactants in soybean oil. The isolate LBPF 3, characterized as Candida antarctica, obtained the highest levels of production - with a final production of 13.86 g/L. The isolate LBPF 9, using glycerol carbon source, obtained the highest reduction in surface tension in the growth medium: approximately 43% of reduction after 24 hours of incubation. The products obtained by the isolates presented surfactant activity, which reduced water surface tension to values that varied from 34 mN/m, obtained from the product of isolates LBPF 3 and 16 LBPF 7 (respectively characterized as Candida antarctica and Candida albicans to 43 mN/m from the isolate LPPF 9, using glycerol as substrate. The assessed isolates all showed potential for the production of biosurfactants in conventional sources of carbon as well as in agroindustrial residue, especially in glycerol.

Biomass production of pleurotus sajor-caju by submerged culture fermentation

International Nuclear Information System (INIS)

Kausar, T.; Nasreen, Z.; Nadeem, M.; Baig, S.

2006-01-01

The effect of different carbon sources, namely, sawdust and powder of agro wastes (as such, or water soluble extracts), and inorganic/natural nitrogen sources on the biomass production of Pleurotus sajor-caju by submerged culture fermentation was studied. Supplementation of the fermentation medium with 2% molasses, 2% wheat spike powder, extract of 2% wheat spike powder, and com gluten meal resulted in 12.85, 10.85, 12.35 and 13.92 g/sub l/ biomass production of P. sajor-caju, respectively. The fungal hyphae biomass contained 8.28% moisture, 21.18% crude protein, 1.55% fat, 3.59% ash, 2.32% crude fibre, and 63.48% nitrogen-free extract. (author)

A Novel Production Method for High-Fructose Glucose Syrup from Sucrose-Containing Biomass by a Newly Isolated Strain of Osmotolerant Meyerozyma guilliermondii.

Science.gov (United States)

Khattab, Sadat Mohammad Rezq; Kodaki, Tsutomu

2016-04-28

One osmotolerant strain from among 44 yeast isolates was selected based on its growth abilities in media containing high concentrations of sucrose. This selected strain, named SKENNY, was identified as Meyerozyma guilliermondii by sequencing the internal transcribed spacer regions and partial D1/D2 large-subunit domains of the 26S ribosomal RNA. SK-ENNY was utilized to produce high-fructose glucose syrup (HFGS) from sucrose-containing biomass. Conversion rates to HFGS from 310-610 g/l of pure sucrose and from 75-310 g/l of sugar beet molasses were 73.5-94.1% and 76.2-91.1%, respectively. In the syrups produced, fructose yields were 89.4-100% and 96.5-100% and glucose yields were 57.6-82.5% and 55.3-79.5% of the theoretical values for pure sucrose and molasses sugars, respectively. This is the first report of employing M. guilliermondii for production of HFGS from sucrose-containing biomass.

Biohydrogen Production from Hydrolysates of Selected Tropical Biomass Wastes with Clostridium Butyricum

Science.gov (United States)

Dan Jiang; Fang, Zhen; Chin, Siew-Xian; Tian, Xiao-Fei; Su, Tong-Chao

2016-06-01

Biohydrogen production has received widespread attention from researchers in industry and academic fields. Response surface methodology (RSM) was applied to evaluate the effects of several key variables in anaerobic fermentation of glucose with Clostridium butyrium, and achieved the highest production rate and yield of hydrogen. Highest H2 yield of 2.02 mol H2/mol-glucose was achieved from 24 h bottle fermentation of glucose at 35 °C, while the composition of medium was (g/L): 15.66 glucose, 6.04 yeast extract, 4 tryptone, 3 K2HPO4, 3 KH2PO4, 0.05 L-cysteine, 0.05 MgSO4·7H2O, 0.1 MnSO4·H2O and 0.3 FeSO4·7H2O, which was very different from that for cell growth. Sugarcane bagasse and Jatropha hulls were selected as typical tropical biomass wastes to produce sugars via a two-step acid hydrolysis for hydrogen production. Under the optimized fermentation conditions, H2 yield (mol H2/mol-total reducing sugar) was 2.15 for glucose, 2.06 for bagasse hydrolysate and 1.95 for Jatropha hull hydrolysate in a 3L fermenter for 24 h at 35 °C, with H2 purity of 49.7-64.34%. The results provide useful information and basic data for practical use of tropical plant wastes to produce hydrogen.

Yeast species diversity in apple juice for cider production evidenced by culture-based method.

Science.gov (United States)

Lorenzini, Marilinda; Simonato, Barbara; Zapparoli, Giacomo

2018-05-07

Identification of yeasts isolated from apple juices of two cider houses (one located in a plain area and one in an alpine area) was carried out by culture-based method. Wallerstein Laboratory Nutrient Agar was used as medium for isolation and preliminary yeasts identification. A total of 20 species of yeasts belonging to ten different genera were identified using both BLAST algorithm for pairwise sequence comparison and phylogenetic approaches. A wide variety of non-Saccharomyces species was found. Interestingly, Candida railenensis, Candida cylindracea, Hanseniaspora meyeri, Hanseniaspora pseudoguilliermondii, and Metschnikowia sinensis were recovered for the first time in the yeast community of an apple environment. Phylogenetic analysis revealed a better resolution in identifying Metschnikowia and Moesziomyces isolates than comparative analysis using the GenBank or YeastIP gene databases. This study provides important data on yeast microbiota of apple juice and evidenced differences between two geographical cider production areas in terms of species composition.

Fuels production by the thermochemical transformation of the biomass

International Nuclear Information System (INIS)

Claudet, G.

2005-01-01

The biomass is a local and renewable energy source, presenting many advantages. This paper proposes to examine the biomass potential in France, the energy valorization channels (thermochemical chains of thermolysis and gasification) with a special interest for the hydrogen production and the research programs oriented towards the agriculture and the forest. (A.L.B.)

Stimulation of Egg Production in Japanese Quails by Enriching Feed with Residual Yeast

Directory of Open Access Journals (Sweden)

Letitia Oprean

2010-05-01

Full Text Available Quail eggs are more and more approved for consumers because they bring many benefits to the human body. Therefore, quails breeding for eggs production have become a very profitable business. Residual yeast may be a nutritional supplement, especially rich in vitamins and proteins. This article studies the influence of residual beer yeast on egg laying in Japanese quails. In order to be integrated into the diet of quails the yeast has undergone a process of autolysis; its influence has been examined on separate groups. The results were reported as a percentage compared with the control group, where the feed does not contain this supplement. Due to its content rich in vitamins and proteins, the residual beer yeast used in feeding the quails bred for eggs stimulates egg laying.

Protein concentrate production from the biomass contaminated with radionuclides

International Nuclear Information System (INIS)

Nizhko, V.F.; Shinkarenko, M.P.; Polozhaj, V.V.; Krivchik, O.V.

1992-01-01

Coefficients of radionuclides accumulation are determined for traditional and rare forage crops grown on contaminated soils. It is shown that with low concentration of radionuclides in soil minimal level of contamination were found in the biomass of lupine (Lupinus luteus L.) and sainfoin (Onobrychis hybridus L.). Relatively high levels of contamination were found in comfrey (Symphytum asperum Lepech.) and bistort (Polygonum divaricatum L.). Comparatively low accumulation coefficients in case of higher density of soil contamination were observed for white and yellow sweetclovers (Melilotus albus Medik. and M. officinalis (L.) Desr.), while higher values of coefficients were found for bird's-foot trefoil (Lotus corniculatus L.), white clover (Trifolium repens L.) and alsike clover (t. hybridum L.). Biomass of white sweet-clover and alsike clover has been processed to produce leaf protein concentrate. It is shown that with biomass contamination of 1 kBq/kg and above conventional technology based on thermal precipitation of the protein does not provide production of pure product. More purified protein concentrates are obtained after two-stage processing of the biomass

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.

Exergy analysis of thermochemical ethanol production via biomass gasification and catalytic synthesis

NARCIS (Netherlands)

van der Heijden, H.H.J.L.; Ptasinski, K.J.

2012-01-01

In this paper an exergy analysis of thermochemical ethanol production from biomass is presented. This process combines a steam-blown indirect biomass gasification of woody feedstock, with a subsequent conversion of produced syngas into ethanol. The production process involves several process

Comparison of biomass productivity and nitrogen fixing potential of Azolla SPP

Energy Technology Data Exchange (ETDEWEB)

Arora, A.; Singh, P.K. [Indian Agricultural Research Inst., New Delhi (India)

2003-03-01

Study was conducted on six different Azolla species, available in the germplasm collection of NCCUBGA, IARI, New Delhi namely A. filiculoides, A. mexicana, A. microphylla, A. pinnata, A. rubra and A. caroliniana in a polyhouse to assess their growth potential by determining their maximal biomass productivity, doubling time and relative growth rates. Their nitrogen fixing potential was assessed by acetylene reduction assay. Among them Azolla microphylla gave highest biomass production and relative growth rate followed by Azolla caroliniana. Both these had high nitrogenase activity also. Peak nitrogenase activity of these strains was found on 14th day of growth and it declined on further incubation. Azolla microphylla and Azolla rubra were more tolerant to salinity than others. On the other hand Azolla pinnata, which is endemic species found in India, exhibited low biomass production, relative growth rate and lower nitrogenase activity compared to other species. It was unable to sustain growth in saline medium. Under polyhouse conditions, A. microphylla was found to perform better than other cultures in terms of biomass productivity, N fixing ability and salt tolerance. Hence it is taken up for mass production.(author)

Continuous ethanol production using yeast immobilized on sugar-cane stalks

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, J.N. de [Alagoas Univ., Maceio, AL (Brazil). Dept. de Engenharia Quimica]. E-mail: jnunes@ctec.ufal.br; Lopes, C.E. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Antibioticos; Franca, F.P. de [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica. Dept. de Engenharia Bioquimica

2004-09-01

Sugar-cane stalks, 2.0 cm long, were used as a support for yeast immobilization envisaging ethanol production. The assays were conducted in 38.5 L fermenters containing a bed of stalks with 50% porosity. The operational stability of the immobilized yeast, the efficiency and stability of the process, as well as the best dilution rate were evaluated. Molasses from demerara sugar production was used in the medium formulation. It was diluted to obtain 111.75 {+-} 1.51 g/L without any further treatment. Sulfuric acid was used to adjust the pH value to around 4.2. Every two days Kamoran HJ (10 ppm) or with a mixture containing penicillin (10 ppm) and tetracycline (10 ppm), was added to the medium. Ethanol yield and efficiency were 29.64 g/L.h and 86.40%, respectively, and the total reducing sugars conversion was 74.61% at a dilution rate of 0.83 h{sup -1}. The yeast-stalk system was shown to be stable for over a 60 day period at extremely variable dilution rates ranging from 0.05 h{sup -1} to 3.00 h{sup -1}. The concentration of immobilized cell reached around 109 cells/gram of dry sugar-cane stalk when the fermenter was operating at the highest dilution rate (3.00 h{sup -1}). (author)

Maximizing renewable hydrogen production from biomass in a bio/catalytic refinery

DEFF Research Database (Denmark)

Westermann, Peter; Jørgensen, Betina; Lange, L.

2007-01-01

Biological production of hydrogen from biomass by fermentative or photofermentative microorganisms has been described in numerous research articles and reviews. The major challenge of these techniques is the low yield from fermentative production, and the large reactor volumes necessary for photo......Biological production of hydrogen from biomass by fermentative or photofermentative microorganisms has been described in numerous research articles and reviews. The major challenge of these techniques is the low yield from fermentative production, and the large reactor volumes necessary...

Lactic acid bacteria and yeasts associated with gowé production from sorghum in Bénin.

Science.gov (United States)

Vieira-Dalodé, G; Jespersen, L; Hounhouigan, J; Moller, P L; Nago, C M; Jakobsen, M

2007-08-01

To identify the dominant micro-organisms involved in the production of gowé, a fermented beverage, and to select the most appropriate species for starter culture development. Samples of sorghum gowé produced twice at three different production sites were taken at different fermentation times. DNA amplification by internal transcribed spacer-polymerase chain reaction of 288 lactic acid bacteria (LAB) isolates and 16S rRNA gene sequencing of selected strains revealed that the dominant LAB responsible for gowé fermentation were Lactobacillus fermentum, Weissella confusa, Lactobacillus mucosae, Pediococcus acidilactici, Pediococcus pentosaceus and Weissella kimchii. DNA from 200 strains of yeasts was amplified and the D1/D2 domain of the 26S rRNA gene was sequenced for selected isolates, revealing that the yeasts species were Kluyveromyces marxianus, Pichia anomala, Candida krusei and Candida tropicalis. Gowé processing is characterized by a mixed fermentation dominated by Lact. fermentum, W. confusa and Ped. acidilactici for the LAB and by K. marxianus, P. anomala and C. krusei for the yeasts. The diversity of the LAB and yeasts identified offers new opportunities for technology upgrading and products development in gowé production. The identified species can be used as possible starter for a controlled fermentation of gowé.

Bio energy: Production of Biomass; Produksjon av biomasse

Energy Technology Data Exchange (ETDEWEB)

Noreng, Katrina; Indergaard, Mentz; Liodden, Ole Joergen; Hohle, Erik Eid; Sandberg, Eiliv

2001-07-01

This is Chapter 2 of the book ''Bio energy - Environment, technique and market''. Its main sections are: (1) Biomass resources in Norway, (2) The foundation - photosynthesis, (3) Biomass from forestry, (4) Biomass from peat lands, (5) Biomass from agriculture and (6) Biomass from lakes and sea. The exposition largely describes the conditions in Norway, where the use of bio energy can be increased from 15 TWh to 35 TWh using available technology. At present, water-borne heating systems are not extensively used in Norway and 30% of the biomass that is cut in the forests remains there as waste. Using this waste for energy generation would not only contribute to reduce the emission of greenhouse gases, but would often lead to improved forest rejuvenation. Use of a few per thousand of the Norwegian peat lands would produce 2 - 3 TWh. According to calculations, along the coast of Norway, there are at least 15 mill tonnes of kelp and sea tangle and these resources can be utilized in a sustainable way.

Aggravated phosphorus limitation on biomass production under increasing nitrogen loading: a meta-analysis.

Science.gov (United States)

Li, Yong; Niu, Shuli; Yu, Guirui

2016-02-01

Nitrogen (N) and phosphorus (P), either individually or in combination, have been demonstrated to limit biomass production in terrestrial ecosystems. Field studies have been extensively synthesized to assess global patterns of N impacts on terrestrial ecosystem processes. However, to our knowledge, no synthesis has been done so far to reveal global patterns of P impacts on terrestrial ecosystems, especially under different nitrogen (N) levels. Here, we conducted a meta-analysis of impacts of P addition, either alone or with N addition, on aboveground (AGB) and belowground biomass production (BGB), plant and soil P concentrations, and N : P ratio in terrestrial ecosystems. Overall, our meta-analysis quantitatively confirmed existing notions: (i) colimitation of N and P on biomass production and (ii) more P limitation in tropical forest than other ecosystems. More importantly, our analysis revealed new findings: (i) P limitation on biomass production was aggravated by N enrichment and (ii) plant P concentration was a better indicator of P limitation than soil P availability. Specifically, P addition increased AGB and BGB by 34% and 13%, respectively. The effect size of P addition on biomass production was larger in tropical forest than grassland, wetland, and tundra and varied with P fertilizer forms, P addition rates, or experimental durations. The P-induced increase in biomass production and plant P concentration was larger under elevated than ambient N. Our findings suggest that the global limitation of P on biomass production will become severer under increasing N fertilizer and deposition in the future. © 2015 John Wiley & Sons Ltd.

Production of ethanol and polyethanol by yeasts isolated from date ...

African Journals Online (AJOL)

Linda

valuation by biotechnological processes enables the production of high value added materials with low cost. In this regard, the objective of this study focused on the selection of yeasts ... produce ethyl alcohol from this waste used in many industries and ... fundamental economic interest. ..... Industrial enzymes from marine.

Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities.

Science.gov (United States)

Muto, Masaki; Nojima, Daisuke; Yue, Liang; Kanehara, Hideyuki; Naruse, Hideaki; Ujiro, Asuka; Yoshino, Tomoko; Matsunaga, Tadashi; Tanaka, Tsuyoshi

2017-03-01

Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 mg/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 ± 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

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

Biomass energy production in agriculture: A weighted goal programming analysis

International Nuclear Information System (INIS)

Ballarin, A.; Vecchiato, D.; Tempesta, T.; Marangon, F.; Troiano, S.

2011-01-01

Energy production from biomasses can be an important resource that, when combined with other green energies such as wind power and solar plants, can contribute to reduce dependency on fossil fuels. The aim of this study is to assess how agriculture could contribute to the production of bio-energy. A multi-period Weighted Goal Programming model (MpWGP) has been applied to identify the optimal land use combinations that simultaneously maximise farmers' income and biomass energy production under three concurrent constraints: water, labour and soil availability. Alternative scenarios are considered that take into account the effect of climate change and social change. The MpWGP model was tested with data from the Rovigo county area (Italy) over a 15-year time period. Our findings show that trade-off exists between the two optimisation targets considered. Although the optimisation of the first target requires traditional agricultural crops, which are characterised by high revenue and a low production of biomass energy, the latter would be achievable with intensive wood production, namely, high-energy production and low income. Our results also show the importance of the constraints imposed, particularly water availability; water scarcity has an overall negative effect and specifically affects the level of energy production. - Research Highlights: → The aim of this study is to assess how agriculture could contribute to the production of bio-energy. → A multi-period (15-year) Weighted Goal Programming model (MpWGP) has been applied. → We identify the optimal land use combinations that simultaneously maximise farmers' income and biomass energy production. → Three concurrent constraints have been considered: water, labour and soil availability.→ Water scarcity has an overall negative effect and specifically affects the level of energy production.

Biomass upgrading by torrefaction for the production of biofuels: A review

International Nuclear Information System (INIS)

Stelt, M.J.C. van der; Gerhauser, H.; Kiel, J.H.A.; Ptasinski, K.J.

2011-01-01

An overview of the research on biomass upgrading by torrefaction for the production of biofuels is presented. Torrefaction is a thermal conversion method of biomass in the low temperature range of 200-300 o C. Biomass is pre-treated to produce a high quality solid biofuel that can be used for combustion and gasification. In this review the characteristics of torrefaction are described and a short history of torrefaction is given. Torrefaction is based on the removal of oxygen from biomass which aims to produce a fuel with increased energy density by decomposing the reactive hemicellulose fraction. Different reaction conditions (temperature, inert gas, reaction time) and biomass resources lead to various solid, liquid and gaseous products. A short overview of the different mass and energy balances is presented. Finally, the technology options and the most promising torrefaction applications and their economic potential are described. -- Highlights: → We reviewed recent developments in biomass upgrading by torrefaction. → Torrefaction improves biomass to a high quality solid fuel. → Main advantages of torrefaction are improvement of energy density and grindability. → Further research on kinetics is recommended for design of torrefaction reactor.

Evaluation of in vitro gas production and nutrient digestibility of complete diets supplemented with different levels of thermotolerant yeast in Nellore rams

Directory of Open Access Journals (Sweden)

Ch. Harikrishna

degradable organic matter were recorded for rations D to D over control, whereas the difference among D to D diets was not 2 6 2 4 significant. Significant (P<0.05 partitioning factor and efficiency of microbial biomass synthesis (EMBP values for rations D and D and significant (P<0.01 microbial biomass production for D to D diets, recorded. Significant (P<0.01 nitrogen 2 3 2 6 (N retention was recorded in yeast supplemented rations with high EMBP than control. Dry matter intake (DMI, DMI (% b. wt., DMI/kg W0.75 and the digestibility of dry matter, organic matter, crude protein, crude fibre, ether extract (P<0.05, nitrogen free extract and fiber fractions were significant (P<0.01 on rations D to D over control, while the difference among 2 4 rations D to D was not significant. All rams were in positive N balance and was higher (P<0.01 on rations D to D over 2 4 2 4 control. The digestible crude protein (DCP and ME were higher (P<0.01 on rations D to D indicating all rams were 2 4 adequately met with DCP and ME requirements as suggested by ICAR, India. Conclusions: The present study demonstrated the potential of theromotolerant yeast at 1 g/kg to 3g/kg level in improving digestibility of nutrients, intake of DCP and ME and N retention without affecting health of rams under study. Thus, incorporation of 1 g/kg level of thermotolerant probiotic yeast in complete diet for lambs appears to be beneficial for livestock producers. [Vet. World 2012; 5(8.000: 477-485

A biotechnological valorization and treatment of olive mill waste waters by selected yeast strains

Directory of Open Access Journals (Sweden)

Mouncif, M.

1995-12-01

Full Text Available Olive mill waste waters were diluted to 1/10, supplied with 2% urea and inoculated with yeast strains. 20 yeast strains isolated from Olive Mill Waste (OMW water were screened for their biomass production, GOD reduction and polyphenols bioconversión activities. Pure cultures of yeasts were realized in 100 ml erlen-meyer flasks. 50 ml cultures were used and the flasks were incubated at room temperature (22°G on a shaker. Biomass production, COD (chemical oxygen demand reduction and Polyphenols bioconversión were followed up in the inoculated OMW waters. Results showed that the urea supply improve significantly the biomass production relatively to the control. This reached in some assays 2.06% expressed as g of biomass dry weight per 100 mL of OMW water. Polyphenols removal was estimated to around 50% and the COD was decreased from 54.14 g/Kg to 21.56 g/Kg. This aerobic treatment lead to the biomass production and also to a pretreated efluent by the COD and the removal of the methanization inhibiting polyphenolic compounds.

Aguas residuales de la molturación de la aceituna se diluyeron en la proporción 1/10, se le añadió un 2% de urea y se inoculó con cepas de levaduras. 20 cepas de levaduras aisladas de aguas residuales de la molturación de la aceituna (OMW se seleccionaron por su producción de biomasa, reducción DQO y actividades de bioconversión de polifenoles. Se llevaron a cabo cultivos puros de levaduras en matraces erlenmeyer de 100 mi. Se tomaron 50 ml de cultivos y los matraces se incubaron a temperatura ambiente (22°C en un agitador. Se siguió la producción de biomasa, la reducción de DQO (demanda química de oxígeno y la bioconversión de polifenoles en las aguas residuales de la aceituna. Los resultados mostraron que el suministro de urea mejoró significativamente la producción de biomasa en relación al control. Esta alcanzó en algunos ensayos el 2.06% expresado como g de peso seco de biomasa por 100 ml de

Effect of methanol feeding strategies on production and yield of recombinant mouse endostatin from Pichia pastoris.

Science.gov (United States)

Trinh, L B; Phue, J N; Shiloach, Joseph

2003-05-20

Pichia pastoris, a methylotrophic yeast, is an efficient producer of recombinant proteins in which the heterologous gene is under the control of the methanol-induced AOX1 promoter. Hence, the accepted production procedure has two phases: In the first phase, the yeast utilizes glycerol and biomass is accumulated; in the second phase, the yeast utilizes methanol which is used both as an inducer for the expression of the recombinant protein and as a carbon source. Since the yeast is sensitive to methanol concentration, the methanol is supplied gradually to the growing culture. Three methanol addition strategies were evaluated for the purpose of optimizing recombinant endostatin production. Two strategies were based on the yeast metabolism; one responding to the methanol consumption using a methanol sensor, and the other responding to the oxygen consumption. In these two strategies, the methanol supply is unlimited. The third strategy was based on a predetermined exponential feeding rate, controling the growth rate at 0.02 h(-1), in this strategy the methanol supply is limited. Throughout the induction phase glycerol, in addition to methanol, was continuously added at a rate of 1 g L h(-1). Total endostatin production was similar in all three strategies, (400 mg was obtained from 3 L initial volume), but the amount of methanol added and the biomass produced were lower in the predetermined rate method. This caused the specific production of endostatin per biomass and per methanol to be 2 times higher in the predetermined rate than in the other two methods, making the growth control strategy not only more efficient but also more convenient for downstream processing. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 82: 438-444, 2003.

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.

Xylitol from rice husks by acid hydrolysis and Candida yeast fermentation

Directory of Open Access Journals (Sweden)

Magale K. D. Rambo

2013-01-01

Full Text Available An investigation was conducted into the production of xylose by acid hydrolysis of rice husks and its subsequent bioconversion to xylitol. The parameters were optimised using the response surface methodology. The fermentation stage took place with the aid of the yeast species Candida guilliermondii and Candida tropicalis. An evaluation of the influence of several biomass pre-treatments was also performed. The effects of the acid concentration and hydrolysate pH on xylitol global yield were also assessed, and the highest yield of xylitol was 64.0% (w/w. The main products, xylose and xylitol, were identified and quantified by means of liquid chromatography.

Very high gravity ethanol fermentation by flocculating yeast under redox potential-controlled conditions

Directory of Open Access Journals (Sweden)

Liu Chen-Guang

2012-08-01

Full Text Available Abstract Background Very high gravity (VHG fermentation using medium in excess of 250 g/L sugars for more than 15% (v ethanol can save energy consumption, not only for ethanol distillation, but also for distillage treatment; however, stuck fermentation with prolonged fermentation time and more sugars unfermented is the biggest challenge. Controlling redox potential (ORP during VHG fermentation benefits biomass accumulation and improvement of yeast cell viability that is affected by osmotic pressure and ethanol inhibition, enhancing ethanol productivity and yield, the most important techno-economic aspect of fuel ethanol production. Results Batch fermentation was performed under different ORP conditions using the flocculating yeast and media containing glucose of 201 ± 3.1, 252 ± 2.9 and 298 ± 3.8 g/L. Compared with ethanol fermentation by non-flocculating yeast, different ORP profiles were observed with the flocculating yeast due to the morphological change associated with the flocculation of yeast cells. When ORP was controlled at −100 mV, ethanol fermentation with the high gravity (HG media containing glucose of 201 ± 3.1 and 252 ± 2.9 g/L was completed at 32 and 56 h, respectively, producing 93.0 ± 1.3 and 120.0 ± 1.8 g/L ethanol, correspondingly. In contrast, there were 24.0 ± 0.4 and 17.0 ± 0.3 g/L glucose remained unfermented without ORP control. As high as 131.0 ± 1.8 g/L ethanol was produced at 72 h when ORP was controlled at −150 mV for the VHG fermentation with medium containing 298 ± 3.8 g/L glucose, since yeast cell viability was improved more significantly. Conclusions No lag phase was observed during ethanol fermentation with the flocculating yeast, and the implementation of ORP control improved ethanol productivity and yield. When ORP was controlled at −150 mV, more reducing power was available for yeast cells to survive, which in turn improved their viability and VHG

Drying enhances immunoactivity of spent brewer's yeast cell wall β-D-glucans.

Science.gov (United States)

Liepins, Janis; Kovačova, Elena; Shvirksts, Karlis; Grube, Mara; Rapoport, Alexander; Kogan, Grigorij

2015-07-20

Due to immunological activity, microbial cell wall polysaccharides are defined as 'biological response modifiers' (BRM). Cell walls of spent brewer's yeast also have some BRM activity. However, up to date there is no consensus on the use of spent brewer's yeast D-glucan as specific BRM in humans or animals. The aim of this paper is to demonstrate the potential of spent brewer's yeast β-D-glucans as BRM, and drying as an efficient pretreatment to increase β-D-glucan's immunogenic activity. Our results revealed that drying does not change spent brewer's yeast biomass carbohydrate content as well as the chemical structure of purified β-D-glucan. However, drying increased purified β-D-glucan TNF-α induction activity in the murine macrophage model. We presume drying pretreatment enhances purity of extracted β-D-glucan. This is corroborated with FT-IR analyses of the β-D-glucan spectra. Based on our results, we suggest that dry spent brewer's yeast biomass can be used as a cheap source for high-quality β-D-glucan extraction. Drying in combination with carboxylmethylation (CM), endows spent brewer's yeast β-D-glucan with the immunoactivity similar or exceeding that of a well-characterized fungal BRM pleuran. Copyright © 2015 Elsevier B.V. All rights reserved.

Furfural and ethanol production from corn stover by dilute phosphoric acid pretreatment

Science.gov (United States)

Lignocellulosic biomass is the most abundant carbohydrate source in the world and has potential for economical production of biofuels, especially ethanol. However, its composition is an obstacle for the production of ethanol by the conventional ethanol producing yeast Saccharomyces cerevisiae as it...

The effect of different nutrient sources on biomass production of ...

African Journals Online (AJOL)

The effect of various organic, inorganic and complex compounds on the biomass production (mycelial dry weight) of Lepiota procera, a Nigerian edible higher fungus was investigated. Among the seventeen carbon compounds tested, mannose enhanced the best biomass yield. This was followed in order by glucose, ...

Influence of aeration and lighting on biomass production and protein ...

African Journals Online (AJOL)

The influence aeration and light intensity could have on biomass production and protein biosynthesis in a Spirulina sp. isolated from an oil-polluted brackish water marsh is examined. Biomass, proximal composition and amino acid composition obtained from aerated cultures of the organism were compared with ...

Comparison of pulp-mill-integrated hydrogen production from gasified black liquor with stand-alone production from gasified biomass

International Nuclear Information System (INIS)

Andersson, E.; Harvey, S.

2007-01-01

When gasified black liquor is used for hydrogen production, significant amounts of biomass must be imported. This paper compares two alternative options for producing hydrogen from biomass: (A) pulp-mill-integrated hydrogen production from gasified back liquor; and (B) stand-alone production of hydrogen from gasified biomass. The comparison assumes that the same amount of biomass that is imported in Alternative A is supplied to a stand-alone hydrogen production plant and that the gasified black liquor in Alternative B is used in a black liquor gasification combined cycle (BLGCC) CHP unit. The comparison is based upon equal amounts of black liquor fed to the gasifier, and identical steam and power requirements for the pulp mill. The two systems are compared on the basis of total CO 2 emission consequences, based upon different assumptions for the reference energy system that reflect different societal CO 2 emissions reduction target levels. Ambitions targets are expected to lead to a more CO 2 -lean reference energy system, in which case hydrogen production from gasified black liquor (Alternative A) is best from a CO 2 emissions' perspective, whereas with high CO 2 emissions associated with electricity production, hydrogen from gasified biomass and electricity from gasified black liquor (Alternative B) is preferable. (author)

Phenotypic and metabolic traits of commercial Saccharomyces cerevisiae yeasts.

Science.gov (United States)

Barbosa, Catarina; Lage, Patrícia; Vilela, Alice; Mendes-Faia, Arlete; Mendes-Ferreira, Ana

2014-01-01

Currently, pursuing yeast strains that display both a high potential fitness for alcoholic fermentation and a favorable impact on quality is a major goal in the alcoholic beverage industry. This considerable industrial interest has led to many studies characterizing the phenotypic and metabolic traits of commercial yeast populations. In this study, 20 Saccharomyces cerevisiae strains from different geographical origins exhibited high phenotypic diversity when their response to nine biotechnologically relevant conditions was examined. Next, the fermentation fitness and metabolic traits of eight selected strains with a unique phenotypic profile were evaluated in a high-sugar synthetic medium under two nitrogen regimes. Although the strains exhibited significant differences in nitrogen requirements and utilization rates, a direct relationship between nitrogen consumption, specific growth rate, cell biomass, cell viability, acetic acid and glycerol formation was only observed under high-nitrogen conditions. In contrast, the strains produced more succinic acid under the low-nitrogen regime, and a direct relationship with the final cell biomass was established. Glucose and fructose utilization patterns depended on both yeast strain and nitrogen availability. For low-nitrogen fermentation, three strains did not fully degrade the fructose. This study validates phenotypic and metabolic diversity among commercial wine yeasts and contributes new findings on the relationship between nitrogen availability, yeast cell growth and sugar utilization. We suggest that measuring nitrogen during the stationary growth phase is important because yeast cells fermentative activity is not exclusively related to population size, as previously assumed, but it is also related to the quantity of nitrogen consumed during this growth phase.

Hydrogen Production Cost Estimate Using Biomass Gasification: Independent Review

Energy Technology Data Exchange (ETDEWEB)

Ruth, M.

2011-10-01

This independent review is the conclusion arrived at from data collection, document reviews, interviews and deliberation from December 2010 through April 2011 and the technical potential of Hydrogen Production Cost Estimate Using Biomass Gasification. The Panel reviewed the current H2A case (Version 2.12, Case 01D) for hydrogen production via biomass gasification and identified four principal components of hydrogen levelized cost: CapEx; feedstock costs; project financing structure; efficiency/hydrogen yield. The panel reexamined the assumptions around these components and arrived at new estimates and approaches that better reflect the current technology and business environments.

Optimization of Baker's Yeast Production on Date Extract Using Response Surface Methodology (RSM).

Science.gov (United States)

Kara Ali, Mounira; Outili, Nawel; Ait Kaki, Asma; Cherfia, Radia; Benhassine, Sara; Benaissa, Akila; Kacem Chaouche, Noreddine

2017-08-07

This work aims to study the production of the biomass of S. cerevisiae on an optimized medium using date extract as the only carbon source in order to obtain a good yield of the biomass. The biomass production was carried out according to the central composite experimental design (CCD) as a response surface methodology using Minitab 16 software. Indeed, under optimal biomass production conditions, temperature (32.9 °C), pH (5.35) and the total reducing sugar extracted from dates (70.93 g/L), S. cerevisiae produced 40 g/L of their biomass in an Erlenmeyer after only 16 h of fermentation. The kinetic performance of the S. cerevisiae strain was investigated with three unstructured models i.e., Monod, Verhulst, and Tessier. The conformity of the experimental data fitted showed a good consistency with Monod and Tessier models with R² = 0.945 and 0.979, respectively. An excellent adequacy was noted in the case of the Verhulst model ( R² = 0.981). The values of kinetic parameters ( Ks , X m , μ m , p and q ) calculated by the Excel software, confirmed that Monod and Verhulst were suitable models, in contrast, the Tessier model was inappropriately fitted with the experimental data due to the illogical value of Ks (-9.434). The profiles prediction of the biomass production with the Verhulst model, and that of the substrate consumption using Leudeking Piret model over time, demonstrated a good agreement between the simulation models and the experimental data.

Productivity and cost of harvesting a stemwood biomass product from integrated cut-to-length harvest operations in Australian Pinus radiata plantations

International Nuclear Information System (INIS)

Walsh, D.; Strandgard, M.

2014-01-01

Significant quantities of woody biomass from the tops of trees and larger woody ‘waste’ pieces that fall outside existing sawlog and pulpwood specifications are left on site post final harvest in Australian radiata Pinus radiata (D. Don) (radiata pine) plantations. Woody biomass is a potential product for pulp making or energy generation. Commercial use of woody biomass from radiata pine plantations would add extra value to the Australian plantation estate through improved resource utilisation, and potentially reduced post-harvesting silvicultural costs. This study investigated the productivity and cost impact of the harvest and extraction to roadside of woody biomass in an integrated harvest operation in a typical Australian two machine (harvester/processor and forwarder), cut-to-length, clearfall operation in a mature, thinned radiata pine plantation. The harvest operation yielded 23 GMt/ha (5% of the total yield) of woody biomass (known as ‘fibreplus’), 443 GMt/ha of sawlogs and 28 GMt/ha of pulpwood. The mean quantity of biomass left on site was 128 GMt/ha, mainly consisting of branches and needles, sufficient to minimise nutrient loss and protect the soil from erosion. Woodchips derived from the fibreplus product were suitable for kraft pulp making, (when blended in small amounts with clean de-barked roundwood woodchips), and for energy generation. The method trialed with the fibreplus product being produced did not impact harvesting and processing productivity and costs, but extraction was 14% less productive. Through analysis of the productivities of each phase and development of a cost model the harvest and extraction of the fibreplus product was estimated to increase total unit costs by ∼4.9%. - Highlights: • Study of the productivity and cost impact of producing a woody biomass product. • We compared two scenarios – harvesting with and without the biomass product. • An additional 23 GMt/ha (5% of the total yield) of woody biomass

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.)

Carbon and nitrogen trade-offs in biomass energy production

Energy Technology Data Exchange (ETDEWEB)

Cucek, Lidija; Klemes, Jiri Jaromir [University of Pannonia, Centre for Process Integration and Intensification (CPI" 2), Research Institute of Chemical and Process Engineering, Faculty of Information Technology, Veszprem (Hungary); Kravanja, Zdravko [University of Maribor, Faculty of Chemistry and Chemical Engineering, Maribor (Slovenia)

2012-06-15

This contribution provides an overview of carbon (CFs) and nitrogen footprints (NFs) concerning their measures and impacts on the ecosystem and human health. The adversarial relationship between them is illustrated by the three biomass energy production applications, which substitute fossil energy production applications: (i) domestic wood combustion where different fossil energy sources (natural gas, coal, and fuel oil) are supplemented, (ii) bioethanol production from corn grain via the dry-grind process, where petrol is supplemented, and (iii) rape methyl ester production from rape seed oil via catalytic trans-esterification, where diesel is supplemented. The life cycle assessment is applied to assess the CFs and NFs resulting from different energy production applications from 'cradle-to-grave' span. The results highlighted that all biomass-derived energy generations have lower CFs and higher NFs whilst, on the other hand, fossil energies have higher CFs and lower NFs. (orig.)

High-temperature ethanol production using thermotolerant yeast newly isolated from Greater Mekong Subregion

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Atiya Techaparin

Full Text Available Abstract The application of high-potential thermotolerant yeasts is a key factor for successful ethanol production at high temperatures. Two hundred and thirty-four yeast isolates from Greater Mekong Subregion (GMS countries, i.e., Thailand, The Lao People's Democratic Republic (Lao PDR and Vietnam were obtained. Five thermotolerant yeasts, designated Saccharomyces cerevisiae KKU-VN8, KKU-VN20, and KKU-VN27, Pichia kudriavzevii KKU-TH33 and P. kudriavzevii KKU-TH43, demonstrated high temperature and ethanol tolerance levels up to 45 °C and 13% (v/v, respectively. All five strains produced higher ethanol concentrations and exhibited greater productivities and yields than the industrial strain S. cerevisiae TISTR5606 during high-temperature fermentation at 40 °C and 43 °C. S. cerevisiae KKU-VN8 demonstrated the best performance for ethanol production from glucose at 37 °C with an ethanol concentration of 72.69 g/L, a productivity of 1.59 g/L/h and a theoretical ethanol yield of 86.27%. The optimal conditions for ethanol production of S. cerevisiae KKU-VN8 from sweet sorghum juice (SSJ at 40 °C were achieved using the Box-Behnken experimental design (BBD. The maximal ethanol concentration obtained during fermentation was 89.32 g/L, with a productivity of 2.48 g/L/h and a theoretical ethanol yield of 96.32%. Thus, the newly isolated thermotolerant S. cerevisiae KKU-VN8 exhibits a great potential for commercial-scale ethanol production in the future.