Exopolysaccharides produced by lactic acid bacteria

NARCIS (Netherlands)

Caggianiello, Graziano; Kleerebezem, Michiel; Spano, Giuseppe

2016-01-01

A wide range of lactic acid bacteria (LAB) is able to produce capsular or extracellular polysaccharides, with various chemical compositions and properties. Polysaccharides produced by LAB alter the rheological properties of the matrix in which they are dispersed, leading to typically viscous and

Decomposition and detoxification of aflatoxin B1 by lactic acid.

Science.gov (United States)

Aiko, Visenuo; Edamana, Prasad; Mehta, Alka

2016-04-01

A degradation study of aflatoxin B1 (AFB1) was carried out using a combination of physical and chemical methods. AFB1 was heated at 80 °C in the presence of acetic, citric and lactic acids for various time periods. The cytotoxicity of the degraded AFB1 and its products were determined by MTT assay. The results showed that among the three organic acids lactic acid was most efficient in degrading AFB1. Although complete degradation was not observed, up to 85% degradation of AFB1 was obtained when heated for 120 min. Degradation of AFB1 was confirmed by the reduced toxicity on HeLa cells using MTT assay. Treatment with lactic acid resulted in the conversion of AFB1 into two degradation products. These products were observed at lower retention factors of 0.63 and 0.38, which were identified as AFB2 and AFB2a, respectively. The cytotoxicity of AFB2a exhibited much reduced toxicity on HeLa cells compared to that of AFB1. The results have shown the efficiency of lactic acid in degrading AFB1. This study suggest that lactic acid may be considered for use in the food and feed industry since it is present naturally in food and is considered safe. © 2015 Society of Chemical Industry.

Catalytic acetoxylation of lactic acid to 2-acetoxypropionic acid, en route to acrylic acid

NARCIS (Netherlands)

Beerthuis, R.; Granollers, M.; Brown, D.R.; Salavagione, H.J.; Rothenberg, G.; Shiju, N.R.

2015-01-01

We present an alternative synthetic route to acrylic acid, starting from the platform chemical lactic acid and using heterogeneous catalysis. To improve selectivity, we designed an indirect dehydration reaction that proceeds via acetoxylation of lactic acid to 2-acetoxypropionic acid. This

Chemical exchange rotation transfer imaging of intermediate-exchanging amines at 2 ppm.

Science.gov (United States)

Zu, Zhongliang; Louie, Elizabeth A; Lin, Eugene C; Jiang, Xiaoyu; Does, Mark D; Gore, John C; Gochberg, Daniel F

2017-10-01

Chemical exchange saturation transfer (CEST) imaging of amine protons exchanging at intermediate rates and whose chemical shift is around 2 ppm may provide a means of mapping creatine. However, the quantification of this effect may be compromised by the influence of overlapping CEST signals from fast-exchanging amines and hydroxyls. We aimed to investigate the exchange rate filtering effect of a variation of CEST, named chemical exchange rotation transfer (CERT), as a means of isolating creatine contributions at around 2 ppm from other overlapping signals. Simulations were performed to study the filtering effects of CERT for the selection of transfer effects from protons of specific exchange rates. Control samples containing the main metabolites in brain, bovine serum albumin (BSA) and egg white albumen (EWA) at their physiological concentrations and pH were used to study the ability of CERT to isolate molecules with amines at 2 ppm that exchange at intermediate rates, and corresponding methods were used for in vivo rat brain imaging. Simulations showed that exchange rate filtering can be combined with conventional filtering based on chemical shift. Studies on samples showed that signal contributions from creatine can be separated from those of other metabolites using this combined filter, but contributions from protein amines may still be significant. This exchange filtering can also be used for in vivo imaging. CERT provides more specific quantification of amines at 2 ppm that exchange at intermediate rates compared with conventional CEST imaging. Copyright © 2017 John Wiley & Sons, Ltd.

Effects of lactic acid bacteria with bacteriocinogenic potential on the fermentation profile and chemical composition of alfalfa silage in tropical conditions.

Science.gov (United States)

Silva, V P; Pereira, O G; Leandro, E S; Da Silva, T C; Ribeiro, K G; Mantovani, H C; Santos, S A

2016-03-01

The fermentation profile, chemical composition, and microbial populations of alfalfa silages treated with microbial inoculants (MI) at different fermentation periods (T) were evaluated in tropical conditions. A 4×6 factorial arrangement was used in a randomized design with 3 replicates. Fresh alfalfa was treated with (1) no treatment (CTRL), (2) commercial inoculant (CIN), (3) Pediococcus acidilactici (strain 10.6, S1), and (4) Pediococcus pentosaceus (strain 6.16, S2). An inoculant application rate of 10(6) cfu/g of fresh forage was used. The fermentation periods were 1, 3, 7, 14, 28, and 56 d. Alfalfa was harvested 82 d after sowing at the early flowering stage, chopped into 1.5-cm particle size, and ensiled in 25 × 35 cm vacuum-sealed plastic bags. The numbers of lactic acid bacteria, enterobacteria, mold, and yeast in alfalfa before ensiling were 5.42, 5.58, 4.82, and 4.8 log cfu/g, respectively. Silage chemical composition was evaluated only at 56 d. All parameters were affected by the interaction MI × T, except the concentrations of lactic and propionic acids. Alfalfa silage treated with S1 or S2 had lower pH values than CTRL from the first day until 28 d. However, the inoculants resulted in similar pH after 56 d, and these values were lower than the CTRL. The highest concentration of lactic acid was observed in the silage treated with S1 and S2 at 7 and 14 d of ensiling. The concentration of acetic acid was lower in the silages treated with S1 and S2 than the CTRL and CIN at 3 and 28 d of fermentation. There was no effect of MI or MI × T interaction on the microbial populations. However, the number of enterobacteria decreased over the fermentation period until 14 d and increased slightly after this time point. The chemical composition of alfalfa silage was not affected by MI at 56 d of ensiling. The strain P. pentosaceus 6.16 was the most efficient in dominating the fermentation process by decreasing the pH more quickly and increasing the concentration

Cascade Production of Lactic Acid from Universal Types of Sugars Catalyzed by Lanthanum Triflate.

Science.gov (United States)

Liu, Dajiang; Kim, Kwang Ho; Sun, Jian; Simmons, Blake A; Singh, Seema

2018-02-09

Lignocellulosic biomass conversion into value-added platform chemicals in the non-toxic, water-tolerant Lewis acid, and water solutions bears the hallmark of green chemistry. Lactic acid derived from biomass is an important chemical building block for biodegradable polymers such as polylactide. Herein, a universal method of converting lignocellulosic sugars into lactic acid using catalytic amount of water-stable Lewis acid La(OTf) 3 is demonstrated. The lignocellulosic sugars studied in this work include 1) pyrolytic sugars from pyrolysis oil, and 2) sugars derived from ionic liquid (IL)-pretreated biomass. Under moderate conditions (250 °C, 1 h), levoglucosan (major pyrolytic sugar), glucose, and xylose were converted into lactic acid with carbon-based molar yields of 75, 74, and 61 %, respectively. Furthermore, roughly 49 mol % (based on levoglucosan) and 74 wt % (relative to pretreated biomass) of lactic acid were obtained from the conversion of pyrolytic sugars and sugar-rich fraction after lignin removal from switchgrass, respectively. To our knowledge, this is the first reported conversion of pyrolytic sugar into lactic acid by chemocatalysis and also lignocellulosic sugars are converted into lactic acid without hydrolysis. This approach could potentially be extended to other lignocellulosic sugars after simple removal of lignin from biomass pretreatment, rendering moderate to high yields of lactic acid. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

13C NMR Chemical Shifts of the Triclinic and Monoclinic Crystal forms of Valinomycin

International Nuclear Information System (INIS)

Kameda, Tsunenori; McGeorge, Gary; Orendt, Anita M.; Grant, David M.

2004-01-01

Two different crystalline polymorphs of valinomycin, the triclinic and monoclinic forms, have been studied by high resolution, solid state 13 C CP-MAS NMR spectroscopy. Although the two polymorphs of the crystal are remarkably similar, there are distinct differences in the isotropic chemical shifts between the two spectra. For the triclinic form, the carbon chemical shift tensor components for the alpha carbons adjacent to oxygen in the lactic acid and hydroxyisovaleric acid residues and the ester carbonyls of the valine residue were obtained using the FIREMAT experiment. From the measured components, it was found that the behavior of the isotropic chemical shift, δ iso , for valine residue ester carbonyl carbons is predominately influenced by the intermediate component, δ 22 . Additionally it was found that the smallest shift component, δ 33 , for the L-lactic acid (L-Lac) and D-α-hydroxyisovaleric acid (D-Hyi) C α -O carbon was significantly displaced depending upon the nature of individual amino acid residues, and it is the δ 33 component that governs the behavior of δ iso in these alpha carbons

Opportunities, perspectives and limits in lactic acid production from waste and industrial by-products

Directory of Open Access Journals (Sweden)

Mladenović Dragana D.

2016-01-01

Full Text Available In line with the goals of sustainable development and environmental protection today great attention is directed towards new technologies for waste and industrial by-products utilization. Waste products represent potentially good raw material for production other valuable products, such as bioethanol, biogas, biodiesel, organic acids, enzymes, microbial biomass, etc. Since the first industrial production to the present, lactic acid has found wide application in food, cosmetic, pharmaceutical and chemical industries. In recent years, the demand for lactic acid has been increasing considerably owing to its potential use as a monomer for the production of poly-lactic acid (PLA polymers which are biodegradable and biocompatible with wide applications. Waste and industrial by-products such are whey, molasses, stillage, waste starch and lignocellulosic materials are a good source of fermentable sugars and many other substances of great importance for the growth of microorganisms, such as proteins, minerals and vitamins. Utilization of waste products for production of lactic acid could help to reduce the total cost of lactic acid production and except the economic viability of the process offers a solution of their disposal. Fermentation process depends on chemical and physical nature of feedstocks and the lactic acid producer. This review describes the characteristics, abilities and limits of microorganisms involved in lactic acid production, as well as the characteristics and types of waste products for lactic acid production. The fermentation methods that have been recently reported to improve lactic acid production are summarized and compared. In order to improve processes and productivity, fed-batch fermentation, fermentation with immobilized cell systems and mixed cultures and opportunities of open (non-sterilized fermentation have been investigated.

Lactic acid Production with in situ Extraction in Membrane Bioreactor

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Hamidreza Ghafouri Taleghani

2017-01-01

Full Text Available Background and Objective: Lactic acid is widely used in the food, chemical and pharmaceutical industries. The major problems associated with lactic acid production are substrate and end-product inhibition, and by-product formation. Membrane technologyrepresents one of the most effective processes for lactic acid production. The aim of this work is to increase cell density and lactic acid productivity due to reduced inhibition effect of substrate and product in membrane bioreactor.Material and Methods: In this work, lactic acid was produced from lactose in membrane bioreactor. A laboratory scale membrane bioreactor was designed and fabricated. Five types of commercial membranes were tested at the same operating conditions (transmembrane pressure: 500 KPa and temperature: 25°C. The effects of initial lactose concentration and dilution rate on biomass growth, lactic acid production and substrate utilization were evaluated.Results and Conclusion: The high lactose retention of 79% v v-1 and low lactic acid retention of 22% v v-1 were obtained with NF1 membrane; therefore, this membrane was selected for membrane bioreactor. The maximal productivity of 17.1 g l-1 h-1 was obtainedwith the lactic acid concentration of 71.5 g l-1 at the dilution rate of 0.24 h−1. The maximum concentration of lactic acid was obtained at the dilution rate of 0.04 h−1. The inhibiting effect of lactic acid was not observed at high initial lactose concentration. The critical lactose concentration at which the cell growth severely hampered was 150 g l-1. This study proved that membrane bioreactor had great advantages such as elimination of substrate and product inhibition, high concentration of process substrate, high cell density,and high lactic acid productivity.Conflict of interest: There is no conflict of interest.

Betaine and beet molasses enhance L-lactic acid production by Bacillus coagulans.

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Ke Xu

Full Text Available Lactic acid is an important chemical with various industrial applications, and it can be efficiently produced by fermentation, in which Bacillus coagulans strains present excellent performance. Betaine can promote lactic acid fermentation as an effective osmoprotectant. Here, positive effect of betaine on fermentation by B. coagulans is revealed. Betaine could enhance lactic acid production by protecting l-LDH activity and cell growth from osmotic inhibition, especially under high glucose concentrations and with poor organic nitrogen nutrients. The fermentation with 0.05 g/L betaine could produce 17.9% more lactic acid compared to the fermentation without betaine. Beet molasses, which is rich in sucrose and betaine, was utilized in a co-feeding fermentation and raised the productivity by 22%. The efficient lactic acid fermentation by B. coagulans is thus developed by using betaine and beet molasses.

Betaine and beet molasses enhance L-lactic acid production by Bacillus coagulans.

Science.gov (United States)

Xu, Ke; Xu, Ping

2014-01-01

Lactic acid is an important chemical with various industrial applications, and it can be efficiently produced by fermentation, in which Bacillus coagulans strains present excellent performance. Betaine can promote lactic acid fermentation as an effective osmoprotectant. Here, positive effect of betaine on fermentation by B. coagulans is revealed. Betaine could enhance lactic acid production by protecting l-LDH activity and cell growth from osmotic inhibition, especially under high glucose concentrations and with poor organic nitrogen nutrients. The fermentation with 0.05 g/L betaine could produce 17.9% more lactic acid compared to the fermentation without betaine. Beet molasses, which is rich in sucrose and betaine, was utilized in a co-feeding fermentation and raised the productivity by 22%. The efficient lactic acid fermentation by B. coagulans is thus developed by using betaine and beet molasses.

Effect of systemic pH on pHi and lactic acid generation in exhaustive forearm exercise

International Nuclear Information System (INIS)

Hood, V.L.; Schubert, C.; Keller, U.; Mueller, S.

1988-01-01

To investigate whether changes in systemic pH affect intracellular pH (pH i ), energy-rich phosphates, and lactic acid generation in muscle, eight normal volunteers performed exhaustive forearm exercise with arterial blood flow occluded for 2 min on three occasions. Subjects ingested 4 mmol/kg NH 4 Cl (acidosis; A) or NaHCO 3 (alkalosis; B) or nothing (control; C) 3 h before the exercise. Muscle pH i and phosphocreatine (PCr) content were measured with 31 P-nuclear magnetic resonance ( 31 P-NMR) spectroscopy during exercise and recovery. Lactate output during 0.5-7 min of recovery was calculated as deep venous-arterial concentration differences times forearm blood flow. Before exercise, blood pH and bicarbonate were lower in acidosis than alkalosis and intermediate in control. Lactic acid output during recovery was less with A than B and intermediate in C. PCr utilization and resynthesis were not affected by extracellular pH changes. pH i did not differ before exercise or at its end. Hence systemic acidosis inhibited and alkalosis stimulated lactic acid output. These findings suggest that systemic pH regulates cellular acid production, protecting muscle pH, at the expense of energy availability

Lactic acid peeling in superficial acne scarring in Indian skin.

Science.gov (United States)

Sachdeva, Silonie

2010-09-01

Chemical peeling with both alpha and beta hydroxy acids has been used to improve acne scarring with pigmentation. Lactic acid, a mild alpha hydroxy acid, has been used in the treatment of various dermatological indications but no study is reported in acne scarring with pigmentation. To evaluate the efficacy and safety of full strength pure lactic acid 92% (pH 2.0) chemical peel in superficial acne scarring in Indian skin. Seven patients, Fitzpatrick skin type IV-V, in age group 20-30 years with superficial acne scarring were enrolled in the study. Chemical peeling was done with lactic acid at an interval of 2 weeks to a maximum of four peels. Pre- and post-peel clinical photographs were taken at every session. Patients were followed every month for 3 months after the last peel to evaluate the effects. At the end of 3 months, there was definite improvement in the texture, pigmentation, and appearance of the treated skin, with lightening of scars. Significant improvement (greater than 75% clearance of lesions) occurred in one patient (14.28%), good improvement (51-75% clearance) in three patients (42.84%), moderate improvement (26-50% clearance) in two patients (28.57%), and mild improvement (1-25% clearance) in one patient (14.28%). © 2010 Wiley Periodicals, Inc.

Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

KAUST Repository

Wang, Zhandong

2017-11-28

Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.

Unraveling the structure and chemical mechanisms of highly oxygenated intermediates in oxidation of organic compounds

KAUST Repository

Wang, Zhandong; Popolan-Vaida, Denisia M.; Chen, Bingjie; Moshammer, Kai; Mohamed, Samah; Wang, Heng; Sioud, Salim; Raji, Misjudeen; Kohse-Hö inghaus, Katharina; Hansen, Nils; Dagaut, Philippe; Leone, Stephen R.; Sarathy, Mani

2017-01-01

Decades of research on the autooxidation of organic compounds have provided fundamental and practical insights into these processes; however, the structure of many key autooxidation intermediates and the reactions leading to their formation still remain unclear. This work provides additional experimental evidence that highly oxygenated intermediates with one or more hydroperoxy groups are prevalent in the autooxidation of various oxygenated (e.g., alcohol, aldehyde, keto compounds, ether, and ester) and nonoxygenated (e.g., normal alkane, branched alkane, and cycloalkane) organic compounds. These findings improve our understanding of autooxidation reaction mechanisms that are routinely used to predict fuel ignition and oxidative stability of liquid hydrocarbons, while also providing insights relevant to the formation mechanisms of tropospheric aerosol building blocks. The direct observation of highly oxygenated intermediates for the autooxidation of alkanes at 500–600 K builds upon prior observations made in atmospheric conditions for the autooxidation of terpenes and other unsaturated hydrocarbons; it shows that highly oxygenated intermediates are stable at conditions above room temperature. These results further reveal that highly oxygenated intermediates are not only accessible by chemical activation but also by thermal activation. Theoretical calculations on H-atom migration reactions are presented to rationalize the relationship between the organic compound’s molecular structure (n-alkane, branched alkane, and cycloalkane) and its propensity to produce highly oxygenated intermediates via extensive autooxidation of hydroperoxyalkylperoxy radicals. Finally, detailed chemical kinetic simulations demonstrate the influence of these additional reaction pathways on the ignition of practical fuels.

Lactic acid bacteria as a cell factory for riboflavin production.

Science.gov (United States)

Thakur, Kiran; Tomar, Sudhir Kumar; De, Sachinandan

2016-07-01

Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin-enriched functional foods, proper selection and exploitation of riboflavin-producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Bioconversion of renewable resources into lactic acid: an industrial view.

Science.gov (United States)

Yadav, A K; Chaudhari, A B; Kothari, R M

2011-03-01

Lactic acid, an anaerobic product of glycolysis, can be theoretically produced by synthetic route; however, it is commercially produced by homo-fermentative batch mode of operations. Factors affecting its production and strategies improving it are considered while devising an optimized protocol. Although a hetero-fermentative mode of production exists, it is rarely used for commercial production. Attempts to use Rhizopus sp. for lactic acid production through either hetero-fermentative or thermophilic conditions were not economical. Since almost 70% of the cost of its production is accounted by raw materials, R & D efforts are still focused to find economically attractive agri-products to serve as sources of carbon and complex nitrogen inputs to meet fastidious nutrient needs for microbial growth and lactic acid production. Therefore, need exists for using multi-pronged strategies for higher productivity. Its present production and consumption scenario is examined. Its optically active isomers and chemical structure permit its use for the production of several industrially important chemicals, health products (probiotics), food preservatives, and bio-plastics. In addition, its salts and esters appear to have a variety of applications.

Simultaneous Saccharification and Fermentation of Sugar Beet Pulp with Mixed Bacterial Cultures for Lactic Acid and Propylene Glycol Production

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Joanna Berlowska

2016-10-01

Full Text Available Research into fermentative production of lactic acid from agricultural by-products has recently concentrated on the direct conversion of biomass, whereby pure sugars are replaced with inexpensive feedstock in the process of lactic acid production. In our studies, for the first time, the source of carbon used is sugar beet pulp, generated as a by-product of industrial sugar production. In this paper, we focus on the simultaneous saccharification of lignocellulosic biomass and fermentation of lactic acid, using mixed cultures with complementary assimilation profiles. Lactic acid is one of the primary platform chemicals, and can be used to synthesize a wide variety of useful products, including green propylene glycol. A series of controlled batch fermentations was conducted under various conditions, including pretreatment with enzymatic hydrolysis. Inoculation was performed in two sequential stages, to avoid carbon catabolite repression. Biologically-synthesized lactic acid was catalytically reduced to propylene glycol over 5% Ru/C. The highest lactic acid yield was obtained with mixed cultures. The yield of propylene glycol from the biological lactic acid was similar to that obtained with a water solution of pure lactic acid. Our results show that simultaneous saccharification and fermentation enables generation of lactic acid, suitable for further chemical transformations, from agricultural residues.

Exploring the chemical kinetics of partially oxidized intermediates by combining experiments, theory, and kinetic modeling.

Science.gov (United States)

Hoyermann, Karlheinz; Mauß, Fabian; Olzmann, Matthias; Welz, Oliver; Zeuch, Thomas

2017-07-19

Partially oxidized intermediates play a central role in combustion and atmospheric chemistry. In this perspective, we focus on the chemical kinetics of alkoxy radicals, peroxy radicals, and Criegee intermediates, which are key species in both combustion and atmospheric environments. These reactive intermediates feature a broad spectrum of chemical diversity. Their reactivity is central to our understanding of how volatile organic compounds are degraded in the atmosphere and converted into secondary organic aerosol. Moreover, they sensitively determine ignition timing in internal combustion engines. The intention of this perspective article is to provide the reader with information about the general mechanisms of reactions initiated by addition of atomic and molecular oxygen to alkyl radicals and ozone to alkenes. We will focus on critical branching points in the subsequent reaction mechanisms and discuss them from a consistent point of view. As a first example of our integrated approach, we will show how experiment, theory, and kinetic modeling have been successfully combined in the first infrared detection of Criegee intermediates during the gas phase ozonolysis. As a second example, we will examine the ignition timing of n-heptane/air mixtures at low and intermediate temperatures. Here, we present a reduced, fuel size independent kinetic model of the complex chemistry initiated by peroxy radicals that has been successfully applied to simulate standard n-heptane combustion experiments.

Advanced Biocatalytic Processing of Heterogeneous Lignocellulosic Feedstocks to a Platform Chemical Intermediate (Lactic acid Ester)

Energy Technology Data Exchange (ETDEWEB)

Dr. Sharon Shoemaker

2004-09-03

The development of commercial boi-based processes and products derived from agricultural waste biomass has the potential for significant impact on the economy and security of our nation. Adding value, rather than disposing of the waste of agriculture, can solve an environmental problem and reduce our dependence on foreign sources of fossil fuel for production of chemicals, materials and fuels.

Beneficial effects of antioxidative lactic acid bacteria

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Hisako Nakagawa

2017-01-01

Full Text Available Oxidative stress is caused by exposure to reactive oxygen intermediates. The oxidative damage of cell components such as proteins, lipids, and nucleic acids one of the important factors associated with diabetes mellitus, cancers and cardiovascular diseases. This occurs as a result of imbalance between the generations of oxygen derived radicals and the organism’s antioxidant potential. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. To date, many studies have focused on food sources, nutrients, and components that exert antioxidant activity in worms, flies, mice, and humans. Probiotics, live microorganisms that when administered in adequate amounts provide many beneficial effects on the human health, have been attracting growing interest for their health-promoting effects, and have often been administered in fermented milk products. In particular, lactic acid bacteria (LAB are known to conferre physiologic benefits. Many studies have indicated the antioxidative activity of LAB. Here we review that the effects of lactic acid bacteria to respond to oxidative stress, is connected to oxidative-stress related disease and aging.

Management of low and intermediate level radioactive wastes with regard to their chemical toxicity

International Nuclear Information System (INIS)

2002-12-01

A preliminary overview is provided of management options for low and intermediate level radioactive waste (LILW) with regard to its chemical toxicity. In particular, the following issues are identified and described associated with the management and safe disposal of chemically toxic materials in LILW: the origin and characteristics; the regulatory approaches; the pre-disposal management; the disposal; the safety assessment. Also included are: regulatory framework for chemically toxic low level wastes in the USA; pre-disposal processing options for LILW containing chemically toxic components; example treatment technologies for LILW containing chemically toxic components and safety assessment case studies for Germany, Belgium, France and Sweden

Study of mixed Ca-Zn hydroxyapatite surface modified by lactic acid

Science.gov (United States)

Turki, Thouraya; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi

2012-07-01

The new hybrid inorganic-organic composites, Ca(10-x)Znx(PO4)6(OH)2-lactic acid, at different amounts of zinc and lactic acid were prepared by dissolution of the organic compound in an hydroxyapatite suspension. They were characterized by XRD, IR, MAS NMR (13C and 1H) and chemical analysis. The crystallinity was slightly affected by the presence of organic fragments. IR and (13C and 1H) MAS NMR measurements indicate that the carboxylic groups of the acid interact with calcium and zinc ions of hydroxyapatite surface. Chemical analysis displays that zinc promotes the acid grafting. A mechanism of surface modification is proposed based on the obtained results.

Study of mixed Ca-Zn hydroxyapatite surface modified by lactic acid

International Nuclear Information System (INIS)

Turki, Thouraya; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi

2012-01-01

The new hybrid inorganic-organic composites, Ca (10-x) Zn x (PO 4 ) 6 (OH) 2 -lactic acid, at different amounts of zinc and lactic acid were prepared by dissolution of the organic compound in an hydroxyapatite suspension. They were characterized by XRD, IR, MAS NMR ( 13 C and 1 H) and chemical analysis. The crystallinity was slightly affected by the presence of organic fragments. IR and ( 13 C and 1 H) MAS NMR measurements indicate that the carboxylic groups of the acid interact with calcium and zinc ions of hydroxyapatite surface. Chemical analysis displays that zinc promotes the acid grafting. A mechanism of surface modification is proposed based on the obtained results.

Physico-chemical parameter for production of lactic acid or ethanol of (corynebacterium glutamicum) bacteria

International Nuclear Information System (INIS)

Castellanos, Angelica; Garcia, Lina Marcela; Astudillo, Myriam; Lopez Galan, Jorge Enrique; Florez Pardo, Luz Marina.

2011-01-01

The interest to obtain products for the bio-fuel industry from renewable resources has directed research to find resistant and costs-effective biotechnological systems. Corynebacterium glutamicum, is a microorganism used to produce amino acids, that grows in wide variety of substrates and its resistance during fermentation to pH, temperature, osmotic pressure variations and alcohol aggregate, renders this organism a suitable candidate to improve by genetic modifications lactic acid and ethanol synthesis. However, some aspects of its physiology remain unknown, such us increase lactic acid and ethanol production from C5 and C6 sugars. For this reason, the main aim in our work was to identify the most important variables with impact on culture and the best culture conditions to produce lactic acid or ethanol in batch culture. To achieve this objective, eight variables were tested in culture using a statistical model. The best culture conditions were obtained and tested in a bacth bioreactor system. Temperature, biotin and glucose concentration were the variables with most impact (p - 1 , 16 g/l of lactic acid was obtained after 15 h of culture with an efficiency of 32%. High glucose consumption was observed during bacterial growth, which leads to low concentration of substrate for the production process; this suggests a culture feeding at the end of exponential growth phase, which can increase the production yield.

L-(+-Lactic acid production by Lactobacillus rhamnosus B103 from dairy industry waste

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Marcela Piassi Bernardo

Full Text Available ABSTRACT Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid, a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7 g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively.

Optimisation of lactic acid fermentation for improved vinegar flavour during rosy vinegar brewing.

Science.gov (United States)

Jiang, Yujian; Guo, Jianna; Li, Yudong; Lin, Sen; Wang, Li; Li, Jianrong

2010-06-01

Rosy vinegar is a well-known traditional Chinese product whose flavour is affected by its lactic acid content. In this study, Lactobacillus bacteria were employed to increase the content of lactic acid during the ethanol fermentation stage. The optimised fermentation parameters were determined as an inoculation amount of 3% (v/v), a temperature of 30 degrees C and an initial pH value of 4.0. Fermentation under these optimal conditions resulted in an alcohol degree of 6.2% (v/v), a total acidity of 49.5 g L(-1) and a lactic acid content of 4.14 g L(-1). The content of lactic acid (4.14 g L(-1)), which approached the level achieved by solid state fermentation, was 3.56-fold higher than that in vinegar fermented without lactic acid bacteria (1.16 g L(-1)). The results indicate that mixed fermentation with Lactobacillus plantarum and Saccharomyces cerevisiae strains greatly increases the lactic acid content and improves the flavour of rosy vinegar. Copyright (c) 2010 Society of Chemical Industry.

Production of lactic acid from sucrose: strain selection, fermentation, and kinetic modeling.

Science.gov (United States)

Lunelli, Betânia H; Andrade, Rafael R; Atala, Daniel I P; Wolf Maciel, Maria Regina; Maugeri Filho, Francisco; Maciel Filho, Rubens

2010-05-01

Lactic acid is an important product arising from the anaerobic fermentation of sugars. It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. In this work, several bacterial strains were isolated from industrial ethanol fermentation, and the most efficient strain for lactic acid production was selected. The fermentation was conducted in a batch system under anaerobic conditions for 50 h at a temperature of 34 degrees C, a pH value of 5.0, and an initial sucrose concentration of 12 g/L using diluted sugarcane molasses. Throughout the process, pulses of molasses were added in order to avoid the cell growth inhibition due to high sugar concentration as well as increased lactic acid concentrations. At the end of the fermentation, about 90% of sucrose was consumed to produce lactic acid and cells. A kinetic model has been developed to simulate the batch lactic acid fermentation results. The data obtained from the fermentation were used for determining the kinetic parameters of the model. The developed model for lactic acid production, growth cell, and sugar consumption simulates the experimental data well.

Optimization of lactic acid production with immobilized Rhizopus ...

African Journals Online (AJOL)

sule

2012-04-26

Apr 26, 2012 ... Lactic acid is the most widely utilized organic acid in the food, pharmaceutical, cosmetics and chemical industries. One of its most promising applications is for used biodegradable and ... polymer supports, by embedding with natural polymers like alginate gels and synthetic polymers (Tamada et al.,. 1992).

Study of mixed Ca-Zn hydroxyapatite surface modified by lactic acid

Energy Technology Data Exchange (ETDEWEB)

Turki, Thouraya; Aissa, Abdallah [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Bac, Christophe Goze [Laboratoire Charles Coulomb, UMR 5221 CNRS/UM2, Universite Montpellier 2, Place E. Bataillon, 34095 Montpellier (France); Rachdi, Ferid, E-mail: Ferid.Rachdi@univ-montp2.fr [Laboratoire Charles Coulomb, UMR 5221 CNRS/UM2, Universite Montpellier 2, Place E. Bataillon, 34095 Montpellier (France); Debbabi, Mongi [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2012-07-01

The new hybrid inorganic-organic composites, Ca{sub (10-x)}Zn{sub x}(PO{sub 4}){sub 6}(OH){sub 2}-lactic acid, at different amounts of zinc and lactic acid were prepared by dissolution of the organic compound in an hydroxyapatite suspension. They were characterized by XRD, IR, MAS NMR ({sup 13}C and {sup 1}H) and chemical analysis. The crystallinity was slightly affected by the presence of organic fragments. IR and ({sup 13}C and {sup 1}H) MAS NMR measurements indicate that the carboxylic groups of the acid interact with calcium and zinc ions of hydroxyapatite surface. Chemical analysis displays that zinc promotes the acid grafting. A mechanism of surface modification is proposed based on the obtained results.

l-(+)-Lactic acid production by Lactobacillus rhamnosus B103 from dairy industry waste.

Science.gov (United States)

Bernardo, Marcela Piassi; Coelho, Luciana Fontes; Sass, Daiane Cristina; Contiero, Jonas

2016-01-01

Lactic acid, which can be obtained through fermentation, is an interesting compound because it can be utilized in different fields, such as in the food, pharmaceutical and chemical industries as a bio-based molecule for bio-refinery. In addition, lactic acid has recently gained more interest due to the possibility of manufacturing poly(lactic acid), a green polymer that can replace petroleum-derived plastics and be applied in medicine for the regeneration of tissues and in sutures, repairs and implants. One of the great advantages of fermentation is the possibility of using agribusiness wastes to obtain optically pure lactic acid. The conventional batch process of fermentation has some disadvantages such as inhibition by the substrate or the final product. To avoid these problems, this study was focused on improving the production of lactic acid through different feeding strategies using whey, a residue of agribusiness. The downstream process is a significant bottleneck because cost-effective methods of producing high-purity lactic acid are lacking. Thus, the investigation of different methods for the purification of lactic acid was one of the aims of this work. The pH-stat strategy showed the maximum production of lactic acid of 143.7g/L. Following purification of the lactic acid sample, recovery of reducing sugars and protein and color removal were 0.28%, 100% and 100%, respectively. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Repressive efficacy of lactic acid bacteria against the human ...

African Journals Online (AJOL)

Different strains of lactic acid bacteria (LAB) namely Lactobacillus acidophilus NCIM 2287, Lactobacillus plantarum NCIM 2085, Lactobacillus helveticus NCIM 2126 and Lactococcus lactis NCIM 2114 were procured from the National Chemical Laboratory (NCL) Pune, India. These LAB cells were individually (107 cfu/ml) ...

Biopropionic acid production via molybdenumcatalyzed deoxygenation of lactic acid

NARCIS (Netherlands)

Korstanje, T.J.; Kleijn, H.; Jastrzebski, J.T.B.H.; Klein Gebbink, R.J.M.

2013-01-01

As the search for non-fossil based building blocks for the chemical industry increases, new methods for the deoxygenation of biomass-derived substrates are required. Here we present the deoxygenation of lactic acid to propionic acid, using a catalyst based on the non-noble and abundant metal

Lactic acid test

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/003507.htm Lactic acid test To use the sharing features on this page, please enable JavaScript. Lactic acid is mainly produced in muscle cells and red ...

Depigmentation and hypertrophic scars after application of a fluid lactic acid tattoo eraser.

Science.gov (United States)

Wollina, Uwe

2015-05-01

Tattoo removal is often requested by patients. The gold standard is laser tattoo removal that can be time- and cost-intensive. Therefore, safe alternatives without lasers, pain, and scars would be desirable. We wanted to address safety of chemical tattoo erasers. We report a case of depigmentation and hypertrophic scars after use of a chemical tattoo eraser and searched the literature. Chemical tattoo erasers are not only used by physicians, but also nonmedical professionals such as beauticians, tattoo artists, and others. The case report we observed and other cases from the literature suggest that lactic acid based tattoo erasers are risky. Available safety data are unsufficient to recommend such procedure as an alternative to current laser therapy. Chemical tattoo erasers based on lactic acid may be capable to remove tattoo ink but the procedure bears safety risks of permanent adverse effects. For the safety of patients, better regulations for tattoo erasers need to be implemented. Patients need to be informed about adverse effects by such procedures.

Metformin-associated lactic acidosis (MALA)

DEFF Research Database (Denmark)

Lalau, Jean-Daniel; Kajbaf, Farshad; Protti, Alessandro

2017-01-01

Although metformin has been used for over 60 years, the balance between the drug's beneficial and adverse effects is still subject to debate. Following an analysis of how cases of so-called "metformin-associated lactic acidosis" (MALA) are reported in the literature, the present article reviews...... the pitfalls to be avoided when assessing the purported association between metformin and lactic acidosis. By starting from pathophysiological considerations, we propose a new paradigm for lactic acidosis in metformin-treated patients. Metformin therapy does not necessarily induce metformin accumulation, just...... as metformin accumulation does not necessarily induce hyperlactatemia, and hyperlactatemia does not necessarily induce lactic acidosis. In contrast to the conventional view, MALA probably accounts for a smaller proportion of cases than either metformin-unrelated lactic acidosis or metformin-induced lactic...

Glutamate Induced Thermal Equilibrium Intermediate and Counteracting Effect on Chemical Denaturation of Proteins.

Science.gov (United States)

Anumalla, Bramhini; Prabhu, N Prakash

2018-01-25

When organisms are subjected to stress conditions, one of their adaptive responses is accumulation of small organic molecules called osmolytes. These osmolytes affect the structure and stability of the biological macromolecules including proteins. The present study examines the effect of a negatively charged amino acid osmolyte, glutamate (Glu), on two model proteins, ribonuclease A (RNase A) and α-lactalbumin (α-LA), which have positive and negative surface charges at pH 7, respectively. These proteins follow two-state unfolding transitions during both heat and chemical induced denaturation processes. The addition of Glu stabilizes the proteins against temperature and induces an early equilibrium intermediate during unfolding. The stability is found to be enthalpy-driven, and the free energy of stabilization is more for α-LA compared to RNase A. The decrease in the partial molar volume and compressibility of both of the proteins in the presence of Glu suggests that the proteins attain a more compact state through surface hydration which could provide a more stable conformation. This is also supported by molecule dynamic simulation studies which demonstrate that the water density around the proteins is increased upon the addition of Glu. Further, the intermediates could be completely destabilized by lower concentrations (∼0.5 M) of guanidinium chloride and salt. However, urea subverts the Glu-induced intermediate formed by α-LA, whereas it only slightly destabilizes in the case of RNase A which has a positive surface charge and could possess charge-charge interactions with Glu. This suggests that, apart from hydration, columbic interactions might also contribute to the stability of the intermediate. Gdm-induced denaturation of RNase A and α-LA in the absence and the presence of Glu at different temperatures was carried out. These results also show the Glu-induced stabilization of both of the proteins; however, all of the unfolding transitions followed two

Treatment of periorbital dark circles: Comparative study of chemical peeling with a combination of trichloroacetic acid and lactic acid versus carboxytherapy

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Arwa Mohammad Hassan

2016-07-01

Full Text Available Periorbital dark circles (PODC are a common worldwide cosmetic problem. It is difficult to treat due to complications in its pathogenesis and aetiology. Available lines of treatment for PODC include whitening creams, topical retinoid acid, chemical peeling, laser therapy, carboxytherapy, autologous fat transplantation, injectable fillers and surgery (blepharoplasty.The aim of this study isto evaluate and compare the efficacy of chemical peels using trichloroacetic acid (3.75% and lactic acid (15% in a gel formula with that of carboxytherapy, in the treatment of periorbital hyperpigmentation.Two groups of patients with PODC were included in the study, named Group A and B in which each group consisted of 15 patients. Group A was assigned for patients who received treatment with chemical peeling with a combination of trichloroacetic acid (3.75% and lactic acid (15% in a gel formula, once a week for four weeks. Group B was assigned for patients who received carboxytherapy that was performed by subcutaneous and intradermal injection of CO2 once a week for four weeks. All patients were assessed by digital photographs, before and after treatment, by observing the improvement in the grade of PODC. Reports of patient satisfaction and global tolerance were evaluated by three medical observers. There was a significant improvement in the grade of PODC in both groups. The degree of improvement of PODC in group A was excellent, with good grade in 93.4% of the treated patients while fair grade in 6.6% of them. There was a statistically significant improvement in the pigmented type. The degree of improvement of PODC in group B was excellent, with good grade in 86.7% of the treated patients while fair grade in 13.3% of them. However, no statistically significant difference between the two groups was observed. Minimal and transient side effects were noticed; however, it did not require further treatment. In conclusion, the two methods of treatment were effective

Lactic acid production from Cellobiose and xylose by engineered Saccharomyces cerevisiae

Science.gov (United States)

Efficient and rapid production of value-added chemicals from lignocellulosic biomass is an important step towards a sustainable society. Lactic acid, used for synthesizing the bioplastic polylactide, has been produced by microbial fermentation using primarily glucose. Lignocellulosic hydrolysates co...

STUDY OF THE EFFECTS SHOWN BY THE ACTION OF VARIOUS MICROORGANISMS ON THE LACTIC FERMENTATION OF JUICES

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Iuliana Manea

2010-01-01

Full Text Available Research has established the most effective lactic acid bacteria used for fermentation of fruit and vegetables juices. The cultures were used for Bifidobacteria, Lactobacillus acidophilus and culture of micro flora obtained spontaneous shoots. Lactic fermented juice was obtained from cabbage, carrots and beetroot. Working in these variants were determined lactic fermentation parameters and some of the bioactive compounds from this process: pH, reducing sugars, viable cell counts. Determination of reducing sugars calculated as glucose was conducted using the 3.5 dinitrosalicilic acid method (DNS method, pH was determined with a pH meter electronics. Chemical parameters listed were determined every two hours during the first 24 hours, then 48 and 72 hours in thermostatic conditions at 37 degrees C and 7 days storage at refrigerator temperature. At the end of the lactic fermentation, the lowest pH 4.31, which also provide juice conservation was obtained using a pure culture of Lactobacillus acidophilus. Reducing sugar is metabolized significantly when the juice of beetroot, fermented with Lactobacillus acidophilus culture, 75.19%. The results may be an argument for obtaining juice fermented lactic acid, which are popular functional foods, to obtain a chemical composition and sensory their optimum.

Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study

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Amrit P. Toor

2011-05-01

Full Text Available The kinetic behavior of esterification of lactic acid with isopropanol over an acidic cation exchange resin, Amberlyst 15, was studied under isothermal condition. Isopropyl lactate synthesized in this reaction is an important pharmaceutical intermediate. The experiments were carried out in a stirred batch reactor in the temperature range of 323.15 to 353.15 K. The effect of various parameters such as temperature, molar ratio and catalyst loading was studied. Variation in parameters on rate of reaction demonstrated that the reaction was intrinsically controlled. Kinetic modeling was performed using Eley-Rideal model which acceptably fits the experimental data. The activation energy was found to be 22.007 kJ/mol and frequency factor was 0.036809 l2 g-1 mol-1 min-1 for forward reaction. The value of entropy for the forward reaction was found to be 182.317 J K-1 mol-1 . © 2011 BCREC UNDIP. All rights reserved(Received: 19th January 2011, Revised: 16th March 2011; Accepted: 16th March 2011[How to Cite: A.P. Toor, M. Sharma, S. Thakur, and R. K. Wanchoo. (2011. Ion-exchange Resin Catalyzed Esterification of Lactic Acid with Isopropanol: a Kinetic Study. Bulletin of Chemical Reaction Engineering and Catalysis, 6(1: 39-45. doi:10.9767/bcrec.6.1.791.39-45][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.6.1.791.39-45 || or local:  http://ejournal.undip.ac.id/index.php/bcrec/article/view/791 ] | View in  

L: (+)-Lactic acid production from non-food carbohydrates by thermotolerant Bacillus coagulans.

Science.gov (United States)

Ou, Mark S; Ingram, Lonnie O; Shanmugam, K T

2011-05-01

Lactic acid is used as an additive in foods, pharmaceuticals, and cosmetics, and is also an industrial chemical. Optically pure lactic acid is increasingly used as a renewable bio-based product to replace petroleum-based plastics. However, current production of lactic acid depends on carbohydrate feedstocks that have alternate uses as foods. The use of non-food feedstocks by current commercial biocatalysts is limited by inefficient pathways for pentose utilization. B. coagulans strain 36D1 is a thermotolerant bacterium that can grow and efficiently ferment pentoses using the pentose-phosphate pathway and all other sugar constituents of lignocellulosic biomass at 50°C and pH 5.0, conditions that also favor simultaneous enzymatic saccharification and fermentation (SSF) of cellulose. Using this bacterial biocatalyst, high levels (150-180 g l(-1)) of lactic acid were produced from xylose and glucose with minimal by-products in mineral salts medium. In a fed-batch SSF of crystalline cellulose with fungal enzymes and B. coagulans, lactic acid titer was 80 g l(-1) and the yield was close to 80%. These results demonstrate that B. coagulans can effectively ferment non-food carbohydrates from lignocellulose to L: (+)-lactic acid at sufficient concentrations for commercial application. The high temperature fermentation of pentoses and hexoses to lactic acid by B. coagulans has these additional advantages: reduction in cellulase loading in SSF of cellulose with a decrease in enzyme cost in the process and a reduction in contamination of large-scale fermentations.

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid/poly(L-lactic acid and self-assembly of polyelectrolytes

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Elena Dellacasa

2016-01-01

Full Text Available The enantiomers poly(D-lactic acid (PDLA and poly(L-lactic acid (PLLA were alternately adsorbed directly on calcium carbonate (CaCO3 templates and on poly(styrene sulfonate (PSS and poly(allylamine hydrochloride (PAH multilayer precursors in order to fabricate a novel layer-by-layer (LBL assembly. A single layer of poly(L-lysine (PLL was used as a linker between the (PDLA/PLLAn stereocomplex and the cores with and without the polymeric (PSS/PAHn/PLL multilayer precursor (PEM. Nuclear magnetic resonance (NMR and gel permeation chromatography (GPC were used to characterize the chemical composition and molecular weight of poly(lactic acid polymers. Both multilayer structures, with and without polymeric precursor, were firstly fabricated and characterized on planar supports. A quartz crystal microbalance (QCM, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR and ellipsometry were used to evaluate the thickness and mass of the multilayers. Then, hollow, spherical microcapsules were obtained by the removal of the CaCO3 sacrificial template. The chemical composition of the obtained microcapsules was confirmed by differential scanning calorimetry (DSC and wide X-ray diffraction (WXRD analyses. The microcapsule morphology was evaluated by scanning electron microscopy (SEM and transmission electron microscopy (TEM measurements. The experimental results confirm the successful fabrication of this innovative system, and its full biocompatibility makes it worthy of further characterization as a promising drug carrier for sustained release.

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

Science.gov (United States)

Yang, Gesheng; Pastorino, Laura

2016-01-01

Summary The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA)n stereocomplex and the cores with and without the polymeric (PSS/PAH)n/PLL multilayer precursor (PEM). Nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) were used to characterize the chemical composition and molecular weight of poly(lactic acid) polymers. Both multilayer structures, with and without polymeric precursor, were firstly fabricated and characterized on planar supports. A quartz crystal microbalance (QCM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and ellipsometry were used to evaluate the thickness and mass of the multilayers. Then, hollow, spherical microcapsules were obtained by the removal of the CaCO3 sacrificial template. The chemical composition of the obtained microcapsules was confirmed by differential scanning calorimetry (DSC) and wide X-ray diffraction (WXRD) analyses. The microcapsule morphology was evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements. The experimental results confirm the successful fabrication of this innovative system, and its full biocompatibility makes it worthy of further characterization as a promising drug carrier for sustained release. PMID:26925356

Engineering CRISPR interference system in Klebsiella pneumoniae for attenuating lactic acid synthesis.

Science.gov (United States)

Wang, Jingxuan; Zhao, Peng; Li, Ying; Xu, Lida; Tian, Pingfang

2018-04-05

Klebsiella pneumoniae is a promising industrial species for bioproduction of bulk chemicals such as 1,3-propanediol, 2,3-butanediol and 3-hydroxypropionic acid (3-HP). However, lactic acid is a troublesome by-product when optimizing for 3-HP production. Therefore, it is highly desirable to minimize lactic acid. Here, we show that lactic acid synthesis can be largely blocked by an engineered CRISPR interference (CRISPRi) system in K. pneumoniae. EGFP was recruited as a reporter of this CRISPRi system. Fluorescence assay of this CRISPRi system showed that enhanced green fluorescent protein (EGFP) expression level was repressed by 85-90%. To further test this CRISPRi system, guide RNAs were designed to individually or simultaneously target four lactate-producing enzyme genes. Results showed that all lactate-producing enzyme genes were significantly repressed. Notably, D-lactate dehydrogenase (ldhA) was shown to be the most influential enzyme for lactic acid formation in micro-aerobic conditions, as inhibiting ldhA alone led to lactic acid level similar to simultaneously repressing four genes. In shake flask cultivation, the strain coexpressing puuC (an aldehyde dehydrogenase catalyzing 3-hydroxypropionaldehyde to 3-HP) and dCas9-sgRNA inhibiting ldhA produced 1.37-fold 3-HP relative to the reference strain. Furthermore, in bioreactor cultivation, this CRISPRi strain inhibiting ldhA produced 36.7 g/L 3-HP, but only generated 1 g/L lactic acid. Clearly, this engineered CRISPRi system largely simplified downstream separation of 3-HP from its isomer lactic acid, an extreme challenge for 3-HP bioprocess. This study offers a deep understanding of lactic acid metabolism in diverse species, and we believe that this CRISPRi system will facilitate biomanufacturing and functional genome studies of K. pneumoniae or beyond.

Intermediate-range chemical ordering of cations in molten RbCl-AgCl

Energy Technology Data Exchange (ETDEWEB)

Tahara, S. [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, Okinawa 903-0213 (Japan); Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), Hyogo 679-5198 (Japan); Kawakita, Y. [J-PARC Center, Japan Atomic Energy Agency (JAEA), Ibaraki 319-1195 (Japan); Shimakura, H. [Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life Sciences, Niigata 956-8603 (Japan); Ohara, K. [Research and Utilization Division, Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), Hyogo 679-5198 (Japan); Fukami, T. [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, Okinawa 903-0213 (Japan); Takeda, S. [Department of Physics, Faculty of Sciences, Kyushu University, Fukuoka 812-8581 (Japan)

2015-07-28

A first sharp diffraction peak (FSDP) is observed in the X-ray total structure factor of a molten mixture of RbCl-AgCl, while both pure melts of RbCl and AgCl do not exhibit FSDP individually. Molecular dynamics simulations were performed to investigate the origin of the FSDP with the polarizable ion model (PIM). Coexistence of covalent Ag–Cl and ionic Rb–Cl bonds leads the system to evolve intermediate range ordering, which is simulated by introducing the induced polarization in different ways between Ag–Cl with fully polarizable treatment based on Vashishta-Raman potential and Rb–Cl with suppression over-polarization in the nearest neighbor contribution based on Born-Meyer potential. The partial structure factors for both the Ag–Ag and Rb–Rb correlations, S{sub AgAg}(Q) and S{sub RbRb}(Q), show a positive contribution to the FSDP, while S{sub AgRb}(Q) for the Ag–Rb correlation exhibits a negative contribution, indicating that Ag and Rb ions are distributed in an alternating manner within the intermediate-range length scale. The origin of the intermediate-range chemical ordering of cations can be ascribed to the preferred direction of the dipole moments of anions in the PIM.

Intermediate-range chemical ordering of cations in molten RbCl-AgCl

International Nuclear Information System (INIS)

Tahara, S.; Kawakita, Y.; Shimakura, H.; Ohara, K.; Fukami, T.; Takeda, S.

2015-01-01

A first sharp diffraction peak (FSDP) is observed in the X-ray total structure factor of a molten mixture of RbCl-AgCl, while both pure melts of RbCl and AgCl do not exhibit FSDP individually. Molecular dynamics simulations were performed to investigate the origin of the FSDP with the polarizable ion model (PIM). Coexistence of covalent Ag–Cl and ionic Rb–Cl bonds leads the system to evolve intermediate range ordering, which is simulated by introducing the induced polarization in different ways between Ag–Cl with fully polarizable treatment based on Vashishta-Raman potential and Rb–Cl with suppression over-polarization in the nearest neighbor contribution based on Born-Meyer potential. The partial structure factors for both the Ag–Ag and Rb–Rb correlations, S AgAg (Q) and S RbRb (Q), show a positive contribution to the FSDP, while S AgRb (Q) for the Ag–Rb correlation exhibits a negative contribution, indicating that Ag and Rb ions are distributed in an alternating manner within the intermediate-range length scale. The origin of the intermediate-range chemical ordering of cations can be ascribed to the preferred direction of the dipole moments of anions in the PIM

Chemical conditions in the repository for low- and intermediate-level reactor waste

International Nuclear Information System (INIS)

Snellman, M.; Uotila, H.

1984-01-01

The chemical conditions in the proposed repositories for low- and intermediate-level reactor waste at Haestholmen (IVO) and Olkiluoto (TVO) have been discussed with respect to materials introduced into the repository, their possible long-term changes and interaction with groundwater flowing into the repository. The main possible groundwater-rock interactions have been discussed, as well as the role of micro-organisms, organic acids and colloids in the estimation of the barrier integrity. Experimental and theoretical studies have been performed on the basis of the natural groundwater compositions expected at the repository sites. Main emphasis is put on the chemical parameters which might influence the integrity of the different barriers in the repository as well as on the parameters which might effect the release and transport of radionuclides from the repository

21 CFR 184.1061 - Lactic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactic acid. 184.1061 Section 184.1061 Food and... Substances Affirmed as GRAS § 184.1061 Lactic acid. (a) Lactic acid (C3H6O3, CAS Reg. Nos.: dl mixture, 598... hydrogen cyanide and subsequent hydrolysis to lactic acid. (b) The ingredient meets the specifications of...

Solution blow spun Poly(lactic acid)/Hydroxypropyl methylcellulose nanofibers with antimicrobial properties

Science.gov (United States)

Poly(lactic acid) (PLA) nanofibers containing hydroxypropyl methylcellulose (HPMC) and tetracycline hydrochloride (THC) were solution blow spun from two different solvents, chloroform/acetone (CA, 80:20 v/v) and 2,2,2-triflouroethanol (TFE). The diameter distribution, chemical, thermal, thermal stab...

Effects of selected lactic acid bacteria on the characteristics of amaranth sourdough.

Science.gov (United States)

Jekle, Mario; Houben, Andreas; Mitzscherling, Martin; Becker, Thomas

2010-10-01

As the processing of amaranth in baked goods is challenging, the use of sourdough fermentation is a promising possibility to exploit the advantages of this raw material. In this study the fermentation properties of Lactobacillus plantarum, Lactobacillus paralimentarius and Lactobacillus helveticus in amaranth-based sourdough were examined in order to validate them as starter cultures. pH, total titratable acidity (TTA) and lactic/acetic acid ratio of the sourdough and sensory properties of the resulting wheat bread were evaluated using fermentation temperatures of 30 and 35 °C. While fermentation pH, TTA and lactic acid concentration showed small variations with the use of L. plantarum and L. paralimentarius, L. helveticus reached the most intensive acidification after initial adaptation to the substrate. Acetic acid production was independent of lactic acid metabolism. Furthermore, the lactic/acetic acid ratio exceeded recommendation by 10-35 times (fermentation quotient 25-82). Sensory evaluation showed no significant differences between the two fermentation temperatures but differences among the three micro-organisms. The results provide relevant information on the fermentation properties required of a customised starter for amaranth flour. Copyright © 2010 Society of Chemical Industry.

A Consistent Methodology Based Parameter Estimation for a Lactic Acid Bacteria Fermentation Model

DEFF Research Database (Denmark)

Spann, Robert; Roca, Christophe; Kold, David

2017-01-01

Lactic acid bacteria are used in many industrial applications, e.g. as starter cultures in the dairy industry or as probiotics, and research on their cell production is highly required. A first principles kinetic model was developed to describe and understand the biological, physical, and chemical...... mechanisms in a lactic acid bacteria fermentation. We present here a consistent approach for a methodology based parameter estimation for a lactic acid fermentation. In the beginning, just an initial knowledge based guess of parameters was available and an initial parameter estimation of the complete set...... of parameters was performed in order to get a good model fit to the data. However, not all parameters are identifiable with the given data set and model structure. Sensitivity, identifiability, and uncertainty analysis were completed and a relevant identifiable subset of parameters was determined for a new...

Biocatalytic Synthesis of Chiral Pharmaceutical Intermediates

Directory of Open Access Journals (Sweden)

Ramesh N. Patel

2004-01-01

Full Text Available The production of single enantiomers of drug intermediates has become increasingly important in the pharmaceutical industry. Chiral intermediates and fine chemicals are in high demand from both the pharmaceutical and agrochemical industries for the preparation of bulk drug substances and agricultural products. The enormous potential of microorganisms and enzymes for the transformation of synthetic chemicals with high chemo-, regio- and enantioselectivities has been demonstrated. In this article, biocatalytic processes are described for the synthesis of chiral pharmaceutical intermediates.

Effect of lactic acid bacteria starter culture fermentation of cassava ...

African Journals Online (AJOL)

The effects of lactic acid fermentation of cassava on the chemical and sensory characteristic of fufu flour were investigated. Two strains of Lactobacillus plantarum were used as starter cultures for the fermentation of cassava to fufu for 96 h. The resultant wet fufu samples were dried at 65oC in a cabinet dryer for 48 h and ...

Significant Lactic Acidosis from Albuterol

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Deborah Diercks

2018-03-01

Full Text Available Lactic acidosis is a clinical entity that demands rapid assessment and treatment to prevent significant morbidity and mortality. With increased lactate use across many clinical scenarios, lactate values themselves cannot be interpreted apart from their appropriate clinical picture. The significance of Type B lactic acidosis is likely understated in the emergency department (ED. Given the mortality that sepsis confers, a serum lactate is an important screening study. That said, it is with extreme caution that we should interpret and react to the resultant elevated value. We report a patient with a significant lactic acidosis. Though he had a high lactate value, he did not require aggressive resuscitation. A different classification scheme for lactic acidosis that focuses on the bifurcation of the “dangerous” and “not dangerous” causes of lactic acidosis may be of benefit. In addition, this case is demonstrative of the potential overuse of lactates in the ED.

Lactic acid production by irradiated Bacillus NF17 and poly-L-lactate biopolymer formation

International Nuclear Information System (INIS)

Tongpim, Saowanit; Poonsawat, Choosak; Khansawai, Paveena; Piadaeng, Nattaya

2006-09-01

This study was conducted to manipulate the thermo tolerant, lactic acid-producing bacteria, Bacillus coagulans strain NF 1 7, in the production of L-lactic acid and a bio polymer: poly-L-lactate. The bacterial isolate NF 1 7 kept in the culture collection of Khon Kaen University and could tolerate high temperature and produce lactic acid, was employed in this research work. Cell suspension of isolate NF 1 7 was exposed to gamma irradiation at various doses (1-5 KGy). The irradiated survivors were screened on the basis of forming larger colonies and clear zones than the parent strain NF 1 7 when grown on Glucose-Yeast extract-Peptone (GYP) containing CaCO 3 . We obtained 55 effective isolates which the isolate L5I2-14(5), designated as K 1 4, was chosen together with the parent strain NF 1 7 for fermentation experiments. Each bacterial strain was inoculated into GYP broth and incubated statically at 50 o C with daily pH neutralization. After 5 days of incubation, the isolate K 1 4 and NF 1 7 produced 9.71 g/l and 7.42 g/l of L-lactic acid, respectively with a small amount of D-lactic acid. Lactic acid production from sugar cane molasses by batch fermentation of Bacillus Sp. K 1 4 was carried out in a 7 l jar fermentor containing 5 l of fermentation medium. It was found that 20% molasses with the agitation speed of 100 rpm gave the highest yield of lactic acid. Poly-L-lactic acid was chemically polymerized by bulk polymerization process at 140 o C under 40 mmHg conditions. We could obtain the off-white polymer in a small amount of powder form. Improvement the yield of poly-L-lactic acid would be achieved by using polyisoprene-g-polyvinyl monomer to separate lactic acid from the fermenting liquid prior to polymerization processes

21 CFR 862.1450 - Lactic acid test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lactic acid test system. 862.1450 Section 862.1450....1450 Lactic acid test system. (a) Identification. A lactic acid test system is a device intended to measure lactic acid in whole blood and plasma. Lactic acid measurements that evaluate the acid-base status...

21 CFR 582.1061 - Lactic acid.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Lactic acid. 582.1061 Section 582.1061 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1061 Lactic acid. (a) Product. Lactic acid. (b) Conditions of use. This substance is generally...

Efficient non-sterilized fermentation of biomass-derived xylose to lactic acid by a thermotolerant Bacillus coagulans NL01.

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Ouyang, Jia; Cai, Cong; Chen, Hai; Jiang, Ting; Zheng, Zhaojuan

2012-12-01

Xylose is the major pentose and the second most abundant sugar in lignocellulosic feedstock. Its efficient utilization is regarded as a technical barrier to the commercial production of bulk chemicals from lignocellulosic biomass. This work aimed at evaluating the lactic acid production from the biomass-derived xylose using non-sterilized fermentation by Bacillus coagulans NL01. A maximum lactic acid concentration of about 75 g/L was achieved from xylose of 100 g/L after 72 h batch fermentation. Acetic acid and levulinic acid were identified as important inhibitors in xylose fermentation, which markedly reduced lactic acid productivity at 15 and 1.0 g/L, respectively. But low concentrations of formic acid (coagulans NL01, the same preference for glucose, xylose, and arabinose was observed and18.2 g/L lactic acid was obtained after 48 h fermentation. These results proved that B. coagulans NL01 was potentially well-suited for producing lactic acid from underutilized xylose-rich prehydrolysates.

Chemical intermediate detection following corona discharge on volatile organic compounds: general method using molecular beam techniques

International Nuclear Information System (INIS)

He Luning; Sulkes, Mark

2011-01-01

Nonthermal plasma (NTP)-based treatments of volatile organic compounds (VOCs) have potential for effective environmental remediation. Theory and experiment that consider the basic science pertaining to discharge events have helped improve NTP remediation outcomes. If direct information on early post-discharge chemical intermediates were also available, it would likely lead to additional improvement in NTP remediation outcomes. To this point, however, experiments yielding direct information on post-NTP VOC intermediates have been limited. An approach using supersonic expansion molecular beam methods offers general promise for detection of post-discharge VOC intermediates. To illustrate the potential utility of these methods, we present mass spectra showing the growth of early products formed when pulsed corona discharges were carried out on toluene in He and then in He with added O 2 . Good general detection of neutral post-discharge species was obtained using 800 nm 150 fs photoionization pulses.

ISOLATION AND IDENTIFICATION OF LACTIC ACID PRODUCING BACTERIA FROM CAMEL MILK

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Toqeer Ahmad, Rashida Kanwal, Izhar Hussain Athar1, Najam Ayub

2002-03-01

Full Text Available Lactic acid bacteria (LAB were isolated from camel milk by culturing the camel milk on specific media and pure culture was obtained by sub culturing. Purification of culture was confirmed by Gram's staining and identified by different bio-chemical tests. Camel milk contains lactic acid producing bacteria including Strpptococci such as S. cremoris and S. lactis and Lactobacilli such as L. acidophilus L. acidophilus grows more rapidly in camel milk than others as its growth is supported by camel milk. A variety of food can be preserved by lactic acid fermentation, so starter culture was prepared from strains which were isolated from camel milk. Camel and buffalo's milk cheese was prepared by using starter culture. The strains isolated from camel milk were best for acid production and can coagulate the milk in less lime. Camel milk cheese was prepared and compared with buffalo's milk cheese. It is concluded that cheese can be prepared successfully from camel milk and better results can be obtained by coagulating milk with starter culture.

Plasma surface modification of poly (L-lactic acid) and poly (lactic-co-glycolic acid) films for improvement of nerve cells adhesion

International Nuclear Information System (INIS)

Khorasani, M.T.; Mirzadeh, H.; Irani, S.

2008-01-01

Radio frequency (RF) plasma treatment in O 2 was applied to modify the surface of poly (L-lactic acid) (PLLA) and poly (D,L-lactic acid-coglycolic acid) (PLGA) as biodegradable polymers. The surface structure, morphology, wettability and surface chemistry of treated films were characterized by water drop contact angle measurement, scanning electron microscope (SEM), optical invert microscope, differential scanning calorimetry (DSC) and ATIR-FTIR spectroscopy. The cell affinity of the oxygen plasma treated film was evaluated by nervous tissue B65 cell culture in stationary conditions. The results showed that the hydrophilicity increased greatly after O 2 plasma treatment. The results showed that improved cell adhesion was attributed to the combination of surface chemistry and surface wettability during plasma treatment. Cell culture results showed that B65 nervous cell attachment and growth on the plasma treated PLLA was much higher than an unmodified sample and PLGA. Surface hydrophilicity and chemical functional groups with high polar component play an important role in enhancing cell attachment and growth

Chemical composition and viability of goat milk whey for the production of lactic acid with Lactobacillus helveticus.

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Alejandra Plata Pinzón

2012-10-01

Full Text Available Goat milk whey is a byproduct of low economic value, and is perceived within Colombia as industrial waste with a negative environmental impact on ecosystems (BOD and COD of 60,000 ppm and 80,000 ppm respectively. Therefore this paper seeks to characterize this whey, and evaluate the effectiveness of the Lactobacillus Helveticus (LH strain from 0 to 0.91 for the production of lactic acid from whey goat milk enriched with three nutrients. The variables studied follow a Greco-Latin model. To this effect, 16 kinetics were conducted in an intermittent bio-fermenter containing 250 milliliters of goat milk whey wherein the highest production of lactic acid, 17.72 grams per liter, is achieved after 50 hours for a medium containing 2.5% yeast, 0.6% riboflavin, 0.45% ammonium sulfate, and the bio-fermenter operating at 42 ° C. The study concludes that apart from producing lactic acid, LH is an alternative towards avoiding contamination of ecosystems in as much as it would generate an added value to the cheese industry

No Evidence of Chemical Abundance Variations in the Intermediate-age Cluster NGC 1783

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Zhang, Hao; de Grijs, Richard; Li, Chengyuan; Wu, Xiaohan

2018-02-01

We have analyzed multi-passband photometric observations, obtained with the Hubble Space Telescope, of the massive (1.8 × 105 M ⊙), intermediate-age (1.8 Gyr-old) Large Magellanic Cloud star cluster NGC 1783. The morphology of the cluster’s red giant branch does not exhibit a clear broadening beyond its intrinsic width; the observed width is consistent with that owing to photometric uncertainties alone and independent of the photometric selection boundaries we applied to obtain our sample of red giant stars. The color dispersion of the cluster’s red giant stars around the best-fitting ridgeline is 0.062 ± 0.009 mag, which is equivalent to the width of 0.080 ± 0.001 mag derived from artificial simple stellar population tests, that is, tests based on single-age, single-metallicity stellar populations. NGC 1783 is comparably as massive as other star clusters that show clear evidence of multiple stellar populations. After incorporating mass-loss recipes from its current age of 1.8 Gyr to an age of 6 Gyr, NGC 1783 is expected to remain as massive as some other clusters that host clear multiple populations at these intermediate ages. If we were to assume that mass is an important driver of multiple population formation, then NGC 1783 should have exhibited clear evidence of chemical abundance variations. However, our results support the absence of any chemical abundance variations in NGC 1783.

EFFECT OF NITROGEN SOURCE AND INITIAL SUGAR CONCENTRATION ON LACTIC ACID FERMENTATION OF PINEAPPLE WASTE USING L.DELBRUECKII

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Abdullah Moch Busairi

2012-02-01

Full Text Available The liquid pineapple waste contains mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for lactic acid fermentation. The lactic acid is utilised in food technology as pH regulator, microbial preservative, buffering agent and in the chemical industry. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were carried out in batch fermentation at anaerobic condition with stirring speed: 50 rpm, temperature: 40 oC, pH: 6.0, and inoculum size: 5%. Effect of nitrogen source and initial sugar concentration were studied. The effect of nitrogen source on lactic acid production shows that the yeast extract is highest yield , followed by urea , corn steep liquor, malt sprout and ammonium sulphates with the yield of 78.52; 26.68; 19.14; 14.10 and 5.6 %, respectively. The highest yield of initial sugar concentration on lactic acid production obtained was 78.52 % (54.97 g/l at 70 g/l, if the concentration of sugar was increased to 110 g/l , the lactic acid production or yield decrease to51.53 g/l or 54.24%.

Simultaneous Saccharification and Fermentation of Lactic Acid from Empty Fruit Bunch at High Solids Loading

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Nursia Hassan

2016-03-01

Full Text Available The production of value-added chemicals from the bioconversion of lignocellulose biomass has been considered a promising venture. In this study, microwave, alkali-pretreated empty fruit bunch (EFB was used as the substrate, utilizing pelletized filamentous Rhizopus oryzae NRRL 395 and cellulolytic enzymes for lactic acid production in a fed-batch simultaneous saccharification and fermentation (SSF process. Insoluble solids generally do not affect the SSF process until a certain concentration is exceeded. To achieve a high lactic acid concentration in the broth, a high solids loading was required to allow a higher rate of glucose conversion. However, the results revealed a decrease in the final lactic acid yield when running SSF at a massive insoluble solids level. High osmotic pressure in the medium led to poor cellular performance and caused the Rhizopus oryzae pellets to break down, affecting the lactic acid production. To improve the process performance, a fed-batch operation mode was used. The fed-batch operation was shown to facilitate higher lactic acid yield, compared with the SSF batch mode. Enzyme feeding, as well as substrate feeding, was also investigated as a means of enabling a higher dry matter content, with a high glucose conversion in SSF of cellulose-rich EFB.

Application of hollow fiber supported liquid membrane as a chemical reactor for esterification of lactic acid and ethanol to ethyl lactate

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Teerachaiyapat, Thanyarutt; Ramakul, Prakorn [Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom (Thailand)

2016-01-15

Hollow fiber supported liquid membrane was applied as a reactor to synthesize ethyl lactate from lactic acid. Lactic acid in the feed solution was extracted by tri-n-octylamine (TOA) and stripped by ethanol with p-toluene sulfonic acid acting as the catalyst to form ethyl lactate. Central composite design (CCD) was used to determine the significant factors and their interactions. The response surface was applied for optimization. An optimized yield of 30% was predicted and its validity was evaluated by comparison with experimental results at different concentrations of lactic acid in the feed solution, with good agreement achieved.

Application of hollow fiber supported liquid membrane as a chemical reactor for esterification of lactic acid and ethanol to ethyl lactate

International Nuclear Information System (INIS)

Teerachaiyapat, Thanyarutt; Ramakul, Prakorn

2016-01-01

Hollow fiber supported liquid membrane was applied as a reactor to synthesize ethyl lactate from lactic acid. Lactic acid in the feed solution was extracted by tri-n-octylamine (TOA) and stripped by ethanol with p-toluene sulfonic acid acting as the catalyst to form ethyl lactate. Central composite design (CCD) was used to determine the significant factors and their interactions. The response surface was applied for optimization. An optimized yield of 30% was predicted and its validity was evaluated by comparison with experimental results at different concentrations of lactic acid in the feed solution, with good agreement achieved.

Continuous lactic fermentation of deproteinized sweet whey

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M. Trujillo

1998-01-01

Full Text Available Whey is a major water contaminant due to its high biochemical oxygen demand (BOD, stemming mainly from its lactose (milk sugar content. The objetive of this research was to investigate the conversion of whey into useful, value-added products. Several methods have been developed already, the most important being dehydration, production of drinks, and conversion of the sugar component into organic acids. Lactic acid including its sodium, calcium, iron and antimony salts, is a valuable product in the alimentary industry and is also a raw material in the chemical industry. To maximize lactic acid production we determined the optimal dilution rate (D carrying out eight fermentations, with D = 0.102 h-1, until the acid production was nil (D= 3.0 h-1. Working conditions were 45 ± 0.1 °C, pH 5.6 ± 0.2, and a cell concentration of 30 ± 4.0 g/L, using Lactobacillus bulgaricus, and deproteinized sweet whey as a substrate. Production of lactic acid and sodium lactate was between 0.5 and 24.37 g/L. Stability of production was reached in average after two retention times. Highest productivity was at D= 0.2 h-1 (2.5 g/Lh , where only 30% of the lactose was consumed from the substrate . Highest lactose consumption was found at D= 0.102 h-1 (53.4%, where productivity was nearly maximal (2.49g/Lh, but acid concentration (26.6% was considerably higher than at the corresponding dilution rate D= 0.2 h-1, which was 14.75 g/L.

Development of a new lactic acid bacterial inoculant for fresh rice straw silage

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Jong Geun Kim

2017-07-01

Full Text Available Objective Effects of newly isolated Lactobacillus plantarum on the fermentation and chemical composition of fresh rice straw silage was evaluated in this study. Methods Lactic acid bacteria (LAB from good crop silage were screened by growing them in MRS broth and a minimal medium with low carbohydrate content. Selected LAB (LAB 1821 were Gram-positive, rods, catalase negative, and were identified to be Lactobacillus plantarum based on their biochemical characteristics and a 16S rRNA analysis. Fresh rice straw was ensiled with two isolated LAB (1821 and 1841, two commercial inoculants (HM/F and P1132 and no additive as a control. Results After 2 months of storage at ambient temperature, rice straw silages treated with additives were well-preserved, the pH values and butyric and acetic acid contents were lower, and the lactic acid content and lactic/acetic acid ratio were higher than those in the control (p0.05 effect on acid detergent fiber or neutral detergent fiber contents. Crude protein (CP content and in vitro DM digestibility (IVDMD increased after inoculation of LAB 1821 (p<0.05. Conclusion LAB 1821 increased the CP, IVDMD, lactic acid content and ratio of lactic acid to acetic acid in rice straw silage and decreased the pH, acetic acid, NH3-N, and butyric acid contents. Therefore, adding LAB 1821 improved the fermentation quality and feed value of rice straw silage.

Analysis of microbial community variation during the mixed culture fermentation of agricultural peel wastes to produce lactic acid.

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Liang, Shaobo; Gliniewicz, Karol; Gerritsen, Alida T; McDonald, Armando G

2016-05-01

Mixed cultures fermentation can be used to convert organic wastes into various chemicals and fuels. This study examined the fermentation performance of four batch reactors fed with different agricultural (orange, banana, and potato (mechanical and steam)) peel wastes using mixed cultures, and monitored the interval variation of reactor microbial communities with 16S rRNA genes using Illumina sequencing. All four reactors produced similar chemical profile with lactic acid (LA) as dominant compound. Acetic acid and ethanol were also observed with small fractions. The Illumina sequencing results revealed the diversity of microbial community decreased during fermentation and a community of largely lactic acid producing bacteria dominated by species of Lactobacillus developed. Copyright © 2016 Elsevier Ltd. All rights reserved.

The chemical, microbial, sensory and technological effects of intermediate salt levels as a sodium reduction strategy in fresh pork sausages.

Science.gov (United States)

Cluff, MacDonald; Steyn, Hannes; Charimba, George; Bothma, Carina; Hugo, Celia J; Hugo, Arno

2016-09-01

The reduction of sodium in processed meat products is synonymous with the use of salt replacers. Rarely has there been an assessment of the use of intermediate salt levels as a sodium reduction strategy in itself. In this study, 1 and 1.5% salt levels were compared with 0 and 2% controls in fresh pork sausages for effects on chemical, microbial, sensory and technological stability. Although significant (P sausages stored at 4 °C on days 6 and 9 and stored at -18 °C on days 90 and 180; taste, texture and overall liking during sensory evaluation; and % cooking loss, % total loss and % refrigeration loss. Consumers were able to differentiate between the 2 and 1% added NaCl treatments in terms of saltiness. This study indicated that salt reduction to intermediate levels can be considered a sodium reduction strategy in itself but that further research with regards to product safety is needed. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

A perspective on Serum Lactic acid, Lactic Acidosis in a Critical Care Unit

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Agela A.Elbadri

2013-06-01

Full Text Available Breast cancer is one of the major surgical problems encountered in Libya. Lactic acidosis is a universal complication in breast cancer patients and can be considered a possible prognostic marker. Therefore, it will be beneficial to correctly understand and review the biochemistry underlying lactic acidosis and its possible significance as a prognostic marker in critical care patients, including breast cancer.

Production of L-lactic Acid from Biomass Wastes Using Scallop Crude Enzymes and Novel Lactic Acid Bacterium

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Yanagisawa, Mitsunori; Nakamura, Kanami; Nakasaki, Kiyohiko

In the present study, biomass waste raw materials including paper mill sludge, bamboo, sea lettuce, and shochu residue (from a distiller) and crude enzymes derived from inedible and discarded scallop parts were used to produce L-lactic acid for the raw material of biodegradable plastic poly-lactic acid. The activities of cellulase and amylase in the crude enzymes were 22 and 170units/L, respectively, and L-lactic acid was produced from every of the above mentioned biomass wastes, by the method of liquid-state simultaneous saccharification and fermentation (SSF) . The L-lactic acid concentrations produced from sea lettuce and shochu residue, which contain high concentration of starch were 3.6 and 9.3g/L, respectively, and corresponded to greater than 25% of the conversion of glucans contained in these biomass wastes. Furthermore, using the solid state SSF method, concentrations as high as 13g/L of L-lactic acid were obtained from sea lettuce and 26g/L were obtained from shochu residue.

Towards lactic acid bacteria-based biorefineries.

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Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica

2014-11-15

Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass. Copyright © 2014 Elsevier Inc. All rights reserved.

Lactic acidosis, hyperlactatemia and sepsis

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Andrea Montagnani

2016-12-01

Full Text Available Among hospitalized patients, lactic acidosis represents the most common cause of metabolic acidosis. Lactate is not just a metabolic product of anaerobic glycolysis but is triggered by a variety of metabolites even before the onset of anaerobic metabolism as part of an adaptive response to a hypermetabolic state. On the basis of such considerations, lactic acidosis is divided into two classes: inadequate tissue oxygenation (type A and absence of tissue hypoxia (type B. Lactic acidosis is characterized by non-specific symptoms but it should be suspected in all critical patients who show hypovolemic, hypoxic, in septic or cardiogenic shock or if in the presence of an unexplained high anion gap metabolic acidosis. Lactic acidosis in sepsis and septic shock has traditionally been explained as a result of tissue hypoxia when whole-body oxygen delivery fails to meet whole body oxygen requirements. In sepsis lactate levels correlate with increased mortality with a poor prognostic threshold of 4 mmol/L. In hemodynamically stable patients with sepsis, hyperlactatemia might be the result of impaired lactate clearance rather than overproduction. In critically ill patients the speed at which hyperlactatemia resolves with appropriate therapy may be considered a useful prognostic indicator. The measure of blood lactate should be performed within 3 h of presentation in acute care setting. The presence of lactic acidosis requires early identification of the primary cause of shock for the best appropriate treatment. Since most cases of lactic acidosis depend on whole-body oxygen delivery failure, the maximization of systemic oxygen delivery remains the primary therapeutic option. When initial resuscitation does not substantially or completely correct lactic acidosis, it is also essential to consider other causes. The treatment of acidosis with buffering agents (specifically bicarbonate is generally advocated only in the setting of severe acidosis. Ongoing

LPMOs in cellulase mixtures affect fermentation strategies for lactic acid production from lignocellulosic biomass.

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Müller, Gerdt; Kalyani, Dayanand Chandrahas; Horn, Svein Jarle

2017-03-01

Enzymatic catalysis plays a key role in the conversion of lignocellulosic biomass to fuels and chemicals such as lactic acid. In the last decade, the efficiency of commercial cellulase cocktails has increased significantly, in part due to the inclusion of lytic polysaccharide monooxygenases (LPMOs). However, the LPMOs' need for molecular oxygen to break down cellulose demands reinvestigations of process conditions. In this study, we evaluate the efficiency of lactic acid production from steam-exploded birch using an LPMO-containing cellulase cocktail in combination with lactic acid bacteria, investigating both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF). While the SSF set up generally has been considered to be more efficient because it avoids sugar accumulation which may inhibit the cellulases, the SHF set up in our study yielded 26-32% more lactic acid than the SSF. This was mainly due to competition for oxygen between LPMOs and the fermenting organisms in the SSF process, which resulted in reduced LPMO activity and thus less efficient saccharification of the lignocellulosic substrate. By means of aeration it was possible to activate the LPMOs in the SSF, but less lactic acid was produced due to a shift in metabolic pathways toward production of acetic acid. Overall, this study shows that lactic acid can be produced efficiently from lignocellulosic biomass, but that the use of LPMO-containing cellulase cocktails in fermentation processes demands re-thinking of traditional process set ups due to the requirement of oxygen in the saccharification step. Biotechnol. Bioeng. 2017;114: 552-559. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Treatment of low and intermediate aqueous waste containing Cs-137 by chemical precipitation

International Nuclear Information System (INIS)

Valdezco, E.M.; Marcelo, E.A.; Alamares, A.L.; Junio, J.B.; Dela Cruz, J.M.

1996-01-01

The use of radioactive materials in various applications has been increasing since its introduction in the early sixties. The Philippine Nuclear Research Institute has established a centralized facility for treating radioactive wastes i.e. aqueous wastes with assistance from the International Atomic Energy Agency - Technical Cooperation Programme. Liquid wastes containing Cs-137 are generated from aqueous wastes containing Cs-137 by nickel ferrocyanide precipitation will be presented. The aim of this study is to investigate the efficiency treatment in removing Cs-137 from an aqueous effluent. Actual aqueous wastes known to contain Cs-137 were used in the experiments. Low cost and simple nickel ferrocyanide precipitation method with the aid of a flocculant has been selected for the separation of Cs-137 from low and intermediate aqueous waste. By varying the chemical dosage added into the aqueous waste, different decontamination factors were obtained. Hence, the optimum dosage of the chemicals that give the highest decontamination factor can be determined. (author)

RECOVERY OF LACTIC ACID FROM AMERICAN CRYSTAL SUGAR COMPANY WASTEWATER

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Daniel J. Stepan; Edwin S. Olson; Richard E. Shockey; Bradley G. Stevens; John R. Gallagher

2001-04-30

, self-supporting thin films and have, therefore, been used for adhesives, safety glass, and finishes. If the bacterial culture produces the L-lactic acid enanatiomer form exclusively, the L-lactide prepared from this form can be used for making polymers with good fiber-forming properties. We have not currently achieved the exclusive production of L-lactate in our efforts. However, markets in films and structural shapes are available for polymers and copolymers prepared from the mixed D,L-lactide forms that result from processing the D,L-lactic acid obtained from fermentation such as that occurring naturally in sugar beet wastewater. These materials are slowly biodegraded to harmless compounds in the environment, and they burn with a clean blue flame when incinerated. These materials represent excellent opportunities for utilization of the D,L-lactic mixture produced from natural fermentation of the ACS flume water. Esters can be converted into a lactide, and the alcohol released from the ester can be recycled with no net consumption of the alcohol. Lactide intermediates could be produced locally and shipped to polymer producers elsewhere. The polymer and copolymer markets are extremely large, and the role of lactides in these markets is continuously expanding. The overall process can be readily integrated into existing factory wastewater operations. There are several environmental benefits that would be realized at the factories with incorporation of the lactate recovery process. The process reduces the organic loading to the existing wastewater treatment system that should result in enhanced operability with respect to both solids handling and treated-water quality. A higher-quality treated water will also help reduce odor levels from holding ponds. Several water reuse opportunities are probable, depending on the quality of treated water from the FT process.

pH-, Lactic Acid-, and Non-Lactic Acid-Dependent Activities of Probiotic Lactobacilli against Salmonella enterica Serovar Typhimurium

OpenAIRE

Fayol-Messaoudi, Domitille; Berger, Cédric N.; Coconnier-Polter, Marie-Hélène; Liévin-Le Moal, Vanessa; Servin, Alain L.

2005-01-01

The mechanism(s) underlying the antibacterial activity of probiotic Lactobacillus strains appears to be multifactorial and includes lowering of the pH and the production of lactic acid and of antibacterial compounds, including bacteriocins and nonbacteriocin, non-lactic acid molecules. Addition of Dulbecco's modified Eagle's minimum essential medium to the incubating medium delays the killing activity of lactic acid. We found that the probiotic strains Lactobacillus johnsonii La1, Lactobacill...

Combination of membrane technologies for purification of L (+) - lactic acid from juice of banana (Musa AAA, variety Cavendish cultivar Gram naine) obtained from an agroindustrial waste

International Nuclear Information System (INIS)

Murillo Viera, Esteban

2013-01-01

The process that has allowed recovery and purification of the L (+)-acid present in the juice fermented waste produced from banana was developed, treated enzymatically, using tangential nanofiltration. The effect of the enzymatic treatment was evaluated on physical chemical parameters of fermented banana juice. The process parameters of centrifugal clarification and microfiltration were characterized on banana juice as activities prior operations to recovery and purification of lactic acid. The temperature and the transmembrane pressure on the permeate flow and the performance of recovery and purification of lactic acid were evaluated by the ultrafiltration and nanofiltration processes. The properties physico-chemical the banana juice fermented and of the liquid filtrate obtained at the stage recovery and purification of lactic acid were compared by ultrafiltration [es

Lactic acid production from biomass-derived sugars via co-fermentation of Lactobacillus brevis and Lactobacillus plantarum.

Science.gov (United States)

Zhang, Yixing; Vadlani, Praveen V

2015-06-01

Lignocellulosic biomass is an attractive alternative resource for producing chemicals and fuels. Xylose is the dominating sugar after hydrolysis of hemicellulose in the biomass, but most microorganisms either cannot ferment xylose or have a hierarchical sugar utilization pattern in which glucose is consumed first. To overcome this barrier, Lactobacillus brevis ATCC 367 was selected to produce lactic acid. This strain possesses a relaxed carbon catabolite repression mechanism that can use glucose and xylose simultaneously; however, lactic acid yield was only 0.52 g g(-1) from a mixture of glucose and xylose, and 5.1 g L(-1) of acetic acid and 8.3 g L(-1) of ethanol were also formed during production of lactic acid. The yield was significantly increased and ethanol production was significantly reduced if L. brevis was co-cultivated with Lactobacillus plantarum ATCC 21028. L. plantarum outcompeted L. brevis in glucose consumption, meaning that L. brevis was focused on converting xylose to lactic acid and the by-product, ethanol, was reduced due to less NADH generated in the fermentation system. Sequential co-fermentation of L. brevis and L. plantarum increased lactic acid yield to 0.80 g g(-1) from poplar hydrolyzate and increased yield to 0.78 g lactic acid per g of biomass from alkali-treated corn stover with minimum by-product formation. Efficient utilization of both cellulose and hemicellulose components of the biomass will improve overall lactic acid production and enable an economical process to produce biodegradable plastics. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

LACTIC FLORA-LISTERIA MONOCYTOGENES INTERACTION

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S. Colombo

2012-08-01

Full Text Available The EC Regulation 2073/2005 (1 requires that food processors evaluate the capability of ready-to-use (RTE products to support the development of Listeria monocytogenes when their pH and aW values are favourable to the growth of this microorganism. It is renown that the lactic flora plays an important role in many different foods, both from a technological and a food safety standpoint. This study was aimed to observe the behaviour and the potential anti-Listeria effect of some natural lactic flora present in Italian liver patè crostini (chicken heart and liver, anchovies, onions, capers, starch, no added preservatives through the Combase Predictor – Max Growth Rate predictive software. The natural lactic flora of the crostini demonstrated a variable capability to inhibit the growth of Listeria monocytogenes which depends upon : the concentration of the lactic flora at the beginning of the shelf life period and the subsequent lag phase, the possible release of anti-Listeria substances, and the maximum growth rate.

A review of DOE chemical and geochemical research programmes (for disposal of low and intermediate level waste)

International Nuclear Information System (INIS)

May, R.

1987-01-01

A study of 26 DOE sponsored research programmes has been carried out with respect to their coverage of various chemical and geochemical issues posed by the proposed disposal of low and intermediate level wastes in a land repository. The study also took into account various experimental programmes sponsored by NIREX and abroad. The findings of the study are reported here. (author)

Sensitive determination of D-lactic acid and L-lactic acid in urine by high-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Henry, H; Marmy Conus, N; Steenhout, P; Béguin, A; Boulat, O

2012-04-01

D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic™ R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis. Copyright © 2011 John Wiley & Sons, Ltd.

PHAGE RESISTANT LACTIC ACID BACTERIAL MUTANTS

DEFF Research Database (Denmark)

2001-01-01

Method of obtaining mutated lactic acid bacteria having a reduced susceptibility towards attack by bacteriophages, the method comprising mutating a gene involved in the pyrimidine metabolism, including pyrG encoding CTP synthetase. Such lactic acid bacteria are useful in starter cultures...

Colonic lactate metabolism and D-lactic acidosis

DEFF Research Database (Denmark)

Hove, H; Mortensen, P B

1995-01-01

D-Lactic acidosis is seen in patients with intestinal bypass or short bowels in whom colonic produced D-lactate accumulates. An intestinal bypassed patient with D-lactic acidosis had higher fecal D-lactate (122.4 mmol/liter) and L-lactate (90.1 mmol/liter) than described before in humans. D......-Lactate fluctuated between 0.5 and 3.1 mmol/liter in plasma (normal liter) and between 1.1 and 52.8 mmol/liter in urine (normal liter) within a few hours, indicating that the human organism do metabolize and excrete D-lactate. The patient with D-lactic acidosis had a 10-fold increased DL......-lactate in feces (84.0 mmol/liter) and plasma (2.3 mmol/liter) considerably in the patient with D-lactic acidosis. Intestinal prolongation (22 cm ileum) had a temporary effect on fecal and plasma D-lactate, but intestinal continuity was reestablished 26 months later because D-lactic acidosis recurred (plasma 8...

Bacteriocins from lactic acid bacteria: purification, properties and use as biopreservatives

OpenAIRE

Parada,José Luis; Caron,Carolina Ricoy; Medeiros,Adriane Bianchi P.; Soccol,Carlos Ricardo

2007-01-01

Biopreservation systems in foods are of increasing interest for industry and consumers. Bacteriocinogenic lactic acid bacteria and/or their isolated bacteriocins are considered safe additives (GRAS), useful to control the frequent development of pathogens and spoiling microorganisms in foods and feed. The spreading of bacterial antibiotic resistance and the demand for products with fewer chemicals create the necessity of exploring new alternatives, in order to reduce the abusive use of therap...

Laboratory Studies of Aedes aegypti Attraction to Ketones, Sulfides, and Primary Chloroalkanes Tested Alone and in Combination with L-Lactic Acid.

Science.gov (United States)

Bernier, Ulrich R; Kline, Daniel L; Allan, Sandra A; Barnard, Donald R

2015-03-01

The attraction of female Aedes aegypti to single compounds and binary compositions containing L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because of their structural relation to acetone, dimethyl disulfide, and dichloromethane, which have all been reported to synergize attraction to L-lactic acid. Human odors, carbon dioxide, and the binary mixture of L-lactic acid and CO₂served as controls for comparison of attraction responses produced by the binary mixtures. All tested mixtures that contained chloroalkanes attracted mosquitoes at synergistic levels, as did L-lactic acid and CO₂. Synergism was less frequent in mixtures of L-lactic acid with sulfides and ketones; in the case of ketones, synergistic attraction was observed only for L-lactic acid combined with acetone or butanone. Suppression or inhibition of attraction response was observed for combinations that contained ketones of C7-C12 molecular chain length (optimum in the C8-C10 range). This inhibition effect is similar to that observed previously for specific ranges of carboxylic acids, aldehydes, and alcohols.

Selection of lactic acid bacteria able to ferment inulin hydrolysates

Directory of Open Access Journals (Sweden)

Octavian BASTON

2012-12-01

Full Text Available Eight homofermentative lactic acid bacteria isolates were tested for lactic acid production using chicory and Jerusalem artichoke hydrolysate as substrate. The pH, lactic acid yield and productivity were used to select the best homolactic bacteria for lactic acid production. The selected strains produced lactic acid at maximum yield after 24 hours of fermentation and the productivity was greater at 24 hours of fermentation. From all studied strains, Lb1 and Lb2 showed the best results regarding lactic acid yields andproductivity. After 48 hours of chicory and Jerusalem artichhoke hydrolysates fermentation, from all the studied strains, Lb2 produced the highest lactic acid yield (0.97%. Lb2 produced after 48 hours of fermentation the lowest pH value of 3.45±0.01. Lb2 showed greater lactic acid productivity compared to the other studied lactic acid bacteria, the highest values, 0.13 g·L-1·h-1fromJerusalem artichoke hydrolysate and 0.11g·L-1·h-1 from chicory hydrolysate, being produced after 24 hours of fermentation.

Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid

Directory of Open Access Journals (Sweden)

Jesús Manuel Quiroz-Castillo

2014-12-01

Full Text Available The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid, promoted by the compatibilizer.

Preparation and Characterization of Films Extruded of Polyethylene/Chitosan Modified with Poly(lactic acid)

Science.gov (United States)

Quiroz-Castillo, Jesús Manuel; Rodríguez-Félix, Dora Evelia; Grijalva-Monteverde, Heriberto; Lizárraga-Laborín, Lauren Lucero; Castillo-Ortega, María Mónica; del Castillo-Castro, Teresa; Rodríguez-Félix, Francisco; Herrera-Franco, Pedro Jesús

2014-01-01

The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed; then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break; additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer. PMID:28787928

Novel Method of Lactic Acid Production by Electrodialysis Fermentation

OpenAIRE

Hongo, Motoyoshi; Nomura, Yoshiyuki; Iwahara, Masayoshi

1986-01-01

In lactic acid fermentation by Lactobacillus delbrueckii, the produced lactic acid affected the lactic acid productivity. Therefore, for the purpose of alleviating this inhibitory effect, an electrodialysis fermentation method which can continuously remove produced lactic acid from the fermentation broth was applied to this fermentation process. As a result, the continuation of fermentation activity was obtained, and the productivity was three times higher than in non-pH-controlled fermentati...

RECOVERY OF LACTIC ACID FROM AMERICAN CRYSTAL SUGAR COMPANY WASTEWATER; TOPICAL

International Nuclear Information System (INIS)

Daniel J, Stepan; Edwin S, Olson; Richard E, Shockey; Bradley G, Stevens; John R, Gallagher

2001-01-01

, self-supporting thin films and have, therefore, been used for adhesives, safety glass, and finishes. If the bacterial culture produces the L-lactic acid enanatiomer form exclusively, the L-lactide prepared from this form can be used for making polymers with good fiber-forming properties. We have not currently achieved the exclusive production of L-lactate in our efforts. However, markets in films and structural shapes are available for polymers and copolymers prepared from the mixed D,L-lactide forms that result from processing the D,L-lactic acid obtained from fermentation such as that occurring naturally in sugar beet wastewater. These materials are slowly biodegraded to harmless compounds in the environment, and they burn with a clean blue flame when incinerated. These materials represent excellent opportunities for utilization of the D,L-lactic mixture produced from natural fermentation of the ACS flume water. Esters can be converted into a lactide, and the alcohol released from the ester can be recycled with no net consumption of the alcohol. Lactide intermediates could be produced locally and shipped to polymer producers elsewhere. The polymer and copolymer markets are extremely large, and the role of lactides in these markets is continuously expanding. The overall process can be readily integrated into existing factory wastewater operations. There are several environmental benefits that would be realized at the factories with incorporation of the lactate recovery process. The process reduces the organic loading to the existing wastewater treatment system that should result in enhanced operability with respect to both solids handling and treated-water quality. A higher-quality treated water will also help reduce odor levels from holding ponds. Several water reuse opportunities are probable, depending on the quality of treated water from the FT process

pH-, Lactic acid-, and non-lactic acid-dependent activities of probiotic Lactobacilli against Salmonella enterica Serovar Typhimurium.

Science.gov (United States)

Fayol-Messaoudi, Domitille; Berger, Cédric N; Coconnier-Polter, Marie-Hélène; Liévin-Le Moal, Vanessa; Servin, Alain L

2005-10-01

The mechanism(s) underlying the antibacterial activity of probiotic Lactobacillus strains appears to be multifactorial and includes lowering of the pH and the production of lactic acid and of antibacterial compounds, including bacteriocins and nonbacteriocin, non-lactic acid molecules. Addition of Dulbecco's modified Eagle's minimum essential medium to the incubating medium delays the killing activity of lactic acid. We found that the probiotic strains Lactobacillus johnsonii La1, Lactobacillus rhamnosus GG, Lactobacillus casei Shirota YIT9029, L. casei DN-114 001, and L. rhamnosus GR1 induced a dramatic decrease in the viability of Salmonella enterica serovar Typhimurium SL1344 mainly attributable to non-lactic acid molecule(s) present in the cell-free culture supernatant (CFCS). These molecules were more active against serovar Typhimurium SL1344 in the exponential growth phase than in the stationary growth phase. We also showed that the production of the non-lactic acid substance(s) responsible for the killing activity was dependent on growth temperature and that both unstable and stable substances with killing activity were present in the CFCSs. We found that the complete inhibition of serovar Typhimurium SL1344 growth results from a pH-lowering effect.

Characterization and ageing study of poly(lactic acid) films plasticized with oligomeric lactic acid

OpenAIRE

Burgos, Nuria; Martino, Verónica P.; Jiménez, Alfonso

2013-01-01

Poly(lactic acid) (PLA) was melt-blended with a bio-based oligomeric lactic acid (OLA) plasticizer at different concentrations between 15 wt% and 25 wt% in order to enhance PLA ductility and to get a fully biodegradable material with potential application in films manufacturing. OLA was an efficient plasticizer for PLA, as it caused a significant decrease on glass transition temperature (Tg) while improving considerably ductile properties. Only one Tg value was observed in all cases and no ap...

Solid state fermentation with lactic acid bacteria to improve the nutritional quality of lupin and soya bean.

Science.gov (United States)

Bartkiene, Elena; Krungleviciute, Vita; Juodeikiene, Grazina; Vidmantiene, Daiva; Maknickiene, Zita

2015-04-01

The ability of bacteriocin-like inhibitory substance (BLIS)-producing lactic acid bacteria (LAB) to degrade biogenic amines as well as to produce L(+) and D(-)-lactic acid during solid state fermentation (SSF) of lupin and soya bean was investigated. In addition, the protein digestibility and formation of organic acids during SSF of legume were investigated. Protein digestibility of fermented lupin and soya bean was found higher on average by 18.3% and 15.9%, respectively, compared to untreated samples. Tested LAB produced mainly L-lactic acid in soya bean and lupin (D/L ratio 0.38-0.42 and 0.35-0.54, respectively), while spontaneous fermentation gave almost equal amounts of both lactic acid isomers (D/L ratio 0.82-0.98 and 0.92, respectively). Tested LAB strains were able to degrade phenylethylamine, spermine and spermidine, whereas they were able to produce putrescine, histamine and tyramine. SSF improved lupin and soya bean protein digestibility. BLIS-producing LAB in lupin and soya bean medium produced a mixture of D- and L-lactic acid with a major excess of the latter isomer. Most toxic histamine and tyramine in fermented lupin and soya bean were found at levels lower those causing adverse health effects. Selection of biogenic amines non-producing bacteria is essential in the food industry to avoid the risk of amine formation. © 2014 Society of Chemical Industry.

INFLUENCE OF PACKAGING MATERIAL AND STORAGE TIME ON PHYSICAL, CHEMICAL AND MICROBIOLOGICAL PROPERTIES OF SET YOGURT: A COMPARATIVE STUDY BETWEEN MODIFIED BIODEGRADABLE POLY(LACTIC ACID AND POLYPROPYLENE

Directory of Open Access Journals (Sweden)

NAWADON PETCHWATTANA

2016-10-01

Full Text Available The current paper investigates the influence of storage time and type of polymeric packaging material on the chemical, physical and microbiological properties of set yogurt. Firstly, poly(lactic acid (PLA was modified by using a core-shell rubber (CSR and an acrylic processing aid (PA to produce PLA with high toughness and good processability. Secondly, an appropriate PLA/PA/CSR composition was selected and fabricated to yogurt cup. The yogurt was stored in both modified PLA and polypropylene (PP packages to observe some physical, chemical and biological changes. Finally, the biodegradation test was made on both packages and compared with that cellulose. Experimental results revealed that adding 5wt% CSR gave PLA/PA as tough as PP. Types of packaging material and storage time did not change the color of yogurt. The number of lactic acid bacteria grew significantly after they had been incubated for 6 days. The bacterial viability decreased dramatically due to the increased acidity and the decreased pH. A positive impact on the viability of bacterial growth was found when yogurt was stored in modified PLA package. This made yogurt had more health benefits than stored in PP package. The biodegradation test results indicated that the modified PLA degraded at a rapid rate. It achieved approximately 50% biodegradation within 40 days which was comparable to the time required to degrade the cellulose, whereas PP was non-biodegradable over the period studied. In summary, substitution conventional PP by a novel modified PLA seems to be a better way for both the health and the environment benefits.

Properties of poly(lactic acid)/hydroxyapatite composite through the use of epoxy functional compatibilizers for biomedical application.

Science.gov (United States)

Monmaturapoj, Naruporn; Srion, Autcharaporn; Chalermkarnon, Prasert; Buchatip, Suthawan; Petchsuk, Atitsa; Noppakunmongkolchai, Warobon; Mai-Ngam, Katanchalee

2017-08-01

A composite of 70/30 poly(lactic acid)/hydroxyapatite was systematically prepared using various amounts of glycidyl methacrylate as reactive compatibilizer or Joncryl ADR®-4368 containing nine glycidyl methacrylate functions as a chain extension/branching agent to improve the mechanical and biological properties for suitable usage as internal bone fixation devices. The effect of glycidyl methacrylate/Joncryl on mechanical properties of poly(lactic acid)/hydroxyapatite was investigated through flexural strength. Cell proliferation and differentiation of osteoblast-like MC3T3-E1 cells cultured on the composite samples were determined by Alamar Blue assay and alkaline phosphatase expression, respectively. Result shows that flexural strength tends to decrease, as glycidyl methacrylate content increases except for 1 wt.% glycidyl methacrylate. With an addition of dicumyl peroxide, the flexural strength shows an improvement than that of without dicumyl peroxide probably due to the chemical bonding of the hydroxyapatite and poly(lactic acid) as revealed by FTIR and NMR, whereas the composite with 5 wt.% Joncryl shows the best result, as the flexural strength increases getting close to pure poly(lactic acid). The significant morphology change could be seen in composite with Joncryl where the uniform agglomeration of hydroxyapatite particles oriented in poly(lactic acid) matrix. Addition of the epoxy functional compatibilizers at suitable percentages could also have benefits to cellular attachment, proliferation, differentiation and mineralization. So that, this poly(lactic acid)/hydroxyapatite composite could be a promising material to be used as internal bone fixation devices such as screws, pins and plates.

Lactic acid production from xylose by Geobacillus stearothermophilus strain 15

Science.gov (United States)

Kunasundari, B.; Naresh, S.; Chu, J. E.

2017-09-01

Lactic acid is an important compound with a wide range of industrial applications. The present study tested the efficiency of xylose, as a sole carbon source to be converted to lactic acid by Geobacillus stearothermophilus strain 15. To the best of our knowledge, limited information is available on the directed fermentation of xylose to lactic acid by this bacterium. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentrations of nitrogen and carbon sources on the lactic acid production were investigated statistically. It was found that the bacterium exhibited poor assimilation of xylose to lactic acid. Temperature, agitation rate and incubation time were determined to improve the lactic acid production slightly. The highest lactic acid yield obtained was 8.9% at 45°C, 300 RPM, 96 h, pH of 6.0 with carbon and nitrogen source concentrations were fixed at 5% w/v.

Efficacy of Lactic Acid, Lactic Acid-Acetic Acid Blends, and Peracetic Acid To Reduce Salmonella on Chicken Parts under Simulated Commercial Processing Conditions.

Science.gov (United States)

Ramirex-Hernandez, Alejandra; Brashears, Mindy M; Sanchez-Plata, Marcos X

2018-01-01

The poultry processing industry has been undergoing a series of changes as it modifies processing practices to comply with new performance standards for chicken parts and comminuted poultry products. The regulatory approach encourages the use of intervention strategies to prevent and control foodborne pathogens in poultry products and thus improve food safety and protect human health. The present studies were conducted to evaluate the efficacy of antimicrobial interventions for reducing Salmonella on inoculated chicken parts under simulated commercial processing conditions. Chicken pieces were inoculated by immersion in a five-strain Salmonella cocktail at 6 log CFU/mL and then treated with organic acids and oxidizing agents on a commercial rinsing conveyor belt. The efficacy of spraying with six different treatments (sterile water, lactic acid, acetic acid, buffered lactic acid, acetic acid in combination with lactic acid, and peracetic acid) at two concentrations was evaluated on skin-on and skin-off chicken thighs at three application temperatures. Skinless chicken breasts were used to evaluate the antimicrobial efficacy of lactic acid and peracetic acid. The color stability of treated and untreated chicken parts was assessed after the acid interventions. The lactic acid and buffered lactic acid treatments produced the greatest reductions in Salmonella counts. Significant differences between the control and water treatments were identified for 5.11% lactic acid and 5.85% buffered lactic acid in both skin-on and skin-off chicken thighs. No significant effect of treatment temperature for skin-on chicken thighs was found. Lactic acid and peracetic acid were effective agents for eluting Salmonella cells attached to chicken breasts.

[Regulating acid stress resistance of lactic acid bacteria--a review].

Science.gov (United States)

Wu, Chongde; Huang, Jun; Zhou, Rongqing

2014-07-04

As cell factories, lactic acid bacteria are widely used in food, agriculture, pharmaceutical and other industries. Acid stress is one the important survival challenges encountered by lactic acid bacteria both in fermentation process and in the gastrointestinal tract. Recently, the development of systems biology and metabolic engineering brings unprecedented opportunity for further elucidating the acid tolerance mechanisms and improving the acid stress resistance of lactic acid bacteria. This review addresses physiological mechanisms of lactic acid bacteria during acid stress. Moreover, strategies to improve the acid stress resistance of lactic acid were proposed.

Spectroscopic studies of neutral and chemically oxidized species of β-carotene, lycopene and norbixin in CH2Cl2: Fluorescence from intermediate compounds

International Nuclear Information System (INIS)

Alwis, D.D.D.H; Chandrika, U.G.; Jayaweera, P.M.

2015-01-01

Radical cations, dications and oxidized intermediate species of three carotenoids, namely, β-carotene, lycopene and norbixin, were generated in CH 2 Cl 2 solutions via chemical oxidation using anhydrous FeCl 3 . UV–vis, fluorescence and fluorescence-excitation spectroscopic studies were performed to understand and compare the nature of intermediate species generated during the chemical oxidation process and subsequent degradation. The intense emission observed at 550 nm can be assigned to the S 2 →S 0 (1 1 B u →1 1 A g ) transition of the carotenoid molecules. The 350 nm excitation during the oxidation process for β-carotene, lycopene and norbixin exhibit intense fluorescence peaks at 492 nm, 493 nm and 500 nm, respectively. These peaks are assigned to intermediate peroxy/epoxy compounds of the three molecules that are formed with molecular oxygen prior to the formation of oxidized short-chain stable compounds. - Highlights: • Fluorescence and UV–vis studies on β-carotene, lycopene and norbixin. • Oxidation, induced by FeCl 3 in CH 2 Cl 2 shows blue shifted fluorescence peaks. • Fluorescence peaks were assigned to intermediate peroxy/epoxy forms of carotenoids. • The D0→D3 transition of radical cations are observed in the near IR region

A method for the determination of D(-)-lactic acid

NARCIS (Netherlands)

Hamer, C.J.A. van den; Elias, R.W.

A method for the determination of D(—)-lactic acid is described. An acetone powder from Escherichia coli B in the presence of methylene blue oxidizes D(—)-lactic specifically. Oxygen consumption in a Warburg apparatus was used as a measure of the D(—)-lactic acid.

Characterization of lactic acid bacteria isolated from Algerian arid ...

African Journals Online (AJOL)

Diversity and density of lactic acid bacteria isolated from Algerian raw goats\\' milk in arid zones were studied by determination of morphological, cultural, physiological and biochemical characteristics. 206 lactic acid bacterial strains were isolated, with 115 of them belonging to lactic acid cocci and others to the genus, ...

Exploring process dynamics by near infrared spectroscopy in lactic fermentations

DEFF Research Database (Denmark)

Svendsen, Carina; Cieplak, Tomasz; van der Berg, Franciscus Winfried J

2016-01-01

In the industrial production of yoghurt, measurement of pH is normally the only in-line technique applied as a real-time monitoring signalfor following the dynamics during the fermentation process. However, every dairy company would benefit from an in-line technique giving information about...... the chemical composition, physical/textural properties and/or microbial contamination. In this study lactic fermentation batches with the starter bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus are explored by in-line near infrared (NIR) spectroscopy. The dynamics obtained...

The possibility of lactic acid fermentation in the triticale stillage

Directory of Open Access Journals (Sweden)

MILICA MARKOVIĆ

2011-06-01

Full Text Available Triticale stillage is a by-product of bioethanol production. A research study was conducted in order to see if triticale stillage is adequate for lactic acid bacteria growth and lactic acid fermentation. Three Lactobacillus strains: Lactobacillus fermentum NRRL-B-75624, Lactobacillus fermentum PL-1, and Lactobacillus plantarum PL-4 were taken into consideration. Lactic acid fermentation was monitored by measuring pH value and titratable acidity. Lactobacillus fermentum PL-1 had the greatest decrease of pH values and increase of titratable acidity so it was chosen for future work. During the research, it was investigated how nutrient composition of triticale stillage and CaCO3 can influence lactic acid fermentation and CaCO3 role in cell protection. The nutrient composition of triticale stillage was satisfactory for lactic acid fermentation. The addition of CaCO3 helped in lactic acid fermentation. Although the titratable acidity in the samples with CaCO3 was lower than in the samples without CaCO3, the number of viable cells was higher for the samples with CaCO3, which showed that CaCO3 protected lactic acid cells from inhibition by lactic acid.

Electron transport chains of lactic acid bacteria

NARCIS (Netherlands)

Brooijmans, R.J.W.

2008-01-01

Lactic acid bacteria are generally considered facultative anaerobic obligate fermentative bacteria. They are unable to synthesize heme. Some lactic acid bacteria are unable to form menaquinone as well. Both these components are cofactors of respiratory (electron transport) chains of prokaryotic

Lactic acid fermentation from refectory waste: Factorial design analysis

African Journals Online (AJOL)

Yomi

2012-04-12

Apr 12, 2012 ... method. At the end of the fermentation process, lactic acid exists in the complex medium of fermentation broth that contains whey proteins, biomass, salts and other impurities. Lactic acid is then recovered from this complex medium. Since the high cost of lactic acid purification process limits the utilization of ...

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals

Science.gov (United States)

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-06-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)-(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized.

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals

International Nuclear Information System (INIS)

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-01-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)–(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized. (focus issue review)

Recent progress in the development of solid catalysts for biomass conversion into high value-added chemicals

Science.gov (United States)

Hara, Michikazu; Nakajima, Kiyotaka; Kamata, Keigo

2015-01-01

In recent decades, the substitution of non-renewable fossil resources by renewable biomass as a sustainable feedstock has been extensively investigated for the manufacture of high value-added products such as biofuels, commodity chemicals, and new bio-based materials such as bioplastics. Numerous solid catalyst systems for the effective conversion of biomass feedstocks into value-added chemicals and fuels have been developed. Solid catalysts are classified into four main groups with respect to their structures and substrate activation properties: (a) micro- and mesoporous materials, (b) metal oxides, (c) supported metal catalysts, and (d) sulfonated polymers. This review article focuses on the activation of substrates and/or reagents on the basis of groups (a)–(d), and the corresponding reaction mechanisms. In addition, recent progress in chemocatalytic processes for the production of five industrially important products (5-hydroxymethylfurfural, lactic acid, glyceraldehyde, 1,3-dihydroxyacetone, and furan-2,5-dicarboxylic acid) as bio-based plastic monomers and their intermediates is comprehensively summarized. PMID:27877800

LACTIC ACIDOSIS: A RARE MANIFESTATION OF SYNTHETIC MARIJUANA INTOXICATION.

Science.gov (United States)

Antill, T; Jakkoju, A; Dieguez, J; Laskhmiprasad, L

2015-01-01

Synthetic cannabinoids are designer drugs that mimic the effect of cannabis, which has become popular with young drug users. These drugs have a similar chemical structure and pharmacologic effects as marijuana, but seem to be more potent. These substances have been banned by the US Drug Enforcement Agency in 2010. Prior to 2010, these drugs were perceived as "safer" by the general population. Synthetic cannabinoids cause effects similar to marijuana making the subjects euphoric. However, they act as full, rather than partial, agonist at the receptor sites causing more severe side effects such as severe agitation, seizures, acute renal failure, and lactic acidosis.

L-Lactic Acid Production by Lactobacillus rhamnosus ATCC 10863

Directory of Open Access Journals (Sweden)

Ana Lívia Chemeli Senedese

2015-01-01

Full Text Available Lactic acid has been shown to have the most promising application in biomaterials as poly(lactic acid. L. rhamnosus ATCC 10863 that produces L-lactic acid was used to perform the fermentation and molasses was used as substrate. A solution containing 27.6 g/L of sucrose (main composition of molasses and 3.0 g/L of yeast extract was prepared, considering the final volume of 3,571 mL (14.0% (v/v inoculum. Batch and fed batch fermentations were performed with temperature of 43.4°C and pH of 5.0. At the fed batch, three molasses feed were applied at 12, 24, and 36 hours. Samples were taken every two hours and the amounts of lactic acid, sucrose, glucose, and fructose were determined by HPLC. The sucrose was barely consumed at both processes; otherwise the glucose and fructose were almost entirely consumed. 16.5 g/L of lactic acid was produced at batch and 22.0 g/L at fed batch. Considering that lactic acid was produced due to the low concentration of the well consumed sugars, the final amount was considerable. The cell growth was checked and no substrate inhibition was observed. A sucrose molasses hydrolysis is suggested to better avail the molasses fermentation with this strain, surely increasing the L-lactic acid.

[Teichoic acids from lactic acid bacteria].

Science.gov (United States)

Livins'ka, O P; Harmasheva, I L; Kovalenko, N K

2012-01-01

The current view of the structural diversity of teichoic acids and their involvement in the biological activity of lactobacilli has been reviewed. The mechanisms of effects of probiotic lactic acid bacteria, in particular adhesive and immunostimulating functions have been described. The prospects of the use of structure data of teichoic acid in the assessment of intraspecific diversity of lactic acid bacteria have been also reflected.

The influence of stress conditions on the growth of selected lactic acid bacteria

International Nuclear Information System (INIS)

Bok, H.E.

1985-01-01

A study was undertaken to determine the effects of certain stress conditions on selected lactic acid bacteria. Where recontamination occurred, lactic acid bacteria was already the dominant bacterial group, with counts of higher than 10 6 /g in vacuum-packaged 'shelf stable' meat products after 1 week storage at 25 and 37 degrees Celsius respectively. Some of the isolates were capable of growing at a pH of 3,9. The minimum pH for growth of a specific culture was dependant on the type of acid that was used to lower the pH. Lactic and acetic acid had the highest inhibitory action. Hydrochloric and citric acid showed similar inhibitory effects, while the effects when using ascorbic acid or gluconic acid for lowering the pH were also fairly similar. Increase in the activity of certain lactic acid bacteria was noticed where the ratio of undissociated to dissociated citric acid in the medium was increased. After exceeding a concentration of 0,048 moles/l undissosiated citric acid in the medium, the activity of the majority of cultures was progressively inhibited. This phenomenon was also found with acetic acid for certain cultures. Selected lactic acid bacteria were resistant to an water activity (a (sub w)) of 0,94 in MRS broth, where NaCl or glycerol was used as a humectant. The minimum a (sub w) for growth was dependent on the type of humectant used. Concentrations of sodium benzoate and potassium sorbate were necessary to inhibit the majority of strains. The % inhibition by sodium benzoate and methyl paraben did not significantly change with a lowering in the pH of the growth medium. Except in the case of lactic acid, the different acids used to lower the pH of the medium did not have a significant effect on the % inhibition by the chemical preservatives. For the cocci, gamma D 10 values of between 0,82 and 1,29 kGy were recorded, whereas the lactobacilli were less resistant to gamma rays, with D 10 values of between 0,21 and 0,54 kGy

The effect of lactic acid bacteria on cocoa bean fermentation.

Science.gov (United States)

Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

2015-07-16

Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

Intensification of conversion of glucose to lactic acid : equilibria and kinetics for back extraction of lactic acid using trimethylamine

NARCIS (Netherlands)

Wasewar, Kailas L.; Heesink, A. Bert M.; Versteeg, Geert F.; Pangarkar, Vishwas G.

2004-01-01

Alamine 336 is an effective extractant for the recovery of lactic acid from aqueous solutions. An approach for regeneration and product recovery from such extracts is to back extract lactic acid with a water soluble, volatile tertiary amine such as trimethyl amine. Equilibrium data are presented

Intensification of conversion of glucose to lactic acid: equilibria and kinetics for back extraction of lactic acid using trimethylamine

NARCIS (Netherlands)

Wasewar, Kailas L.; Heesink, Albertus B.M.; Versteeg, Geert; Pangarkar, Vishwas G.

2004-01-01

Alamine 336 is an effective extractant for the recovery of lactic acid from aqueous solutions. An approach for regeneration and product recovery from such extracts is to back extract lactic acid with a water soluble, volatile tertiary amine such as trimethyl amine. Equilibrium data are presented

Engineering strategies aimed at control of acidification rate of lactic acid bacteria

DEFF Research Database (Denmark)

Martinussen, Jan; Solem, Christian; Holm, Anders Koefoed

2013-01-01

The ability of lactic acid bacteria to produce lactic acid from various sugars plays an important role in food fermentations. Lactic acid is derived from pyruvate, the end product of glycolysis and thus a fast lactic acid production rate requires a high glycolytic flux. In addition to lactic acid......, alternative end products - ethanol, acetic acid and formic acid - are formed by many species. The central role of glycolysis in lactic acid bacteria has provoked numerous studies aiming at identifying potential bottleneck(s) since knowledge about flux control could be important not only for optimizing food...

Contributory roles of two l-lactate dehydrogenases for l-lactic acid production in thermotolerant Bacillus coagulans.

Science.gov (United States)

Sun, Lifan; Zhang, Caili; Lyu, Pengcheng; Wang, Yanping; Wang, Limin; Yu, Bo

2016-11-25

Thermotolerant Bacillus coagulans is considered to be a more promising producer for bio-chemicals, due to its capacity to withstand harsh conditions. Two L-lactate dehydrogenase (LDH) encoding genes (ldhL1 and ldhL2) and one D-LDH encoding gene (ldhD) were annotated from the B. coagulans DSM1 genome. Transcriptional analysis revealed that the expression of ldhL2 was undetectable while the ldhL1 transcription level was much higher than that of ldhD at all growth phases. Deletion of the ldhL2 gene revealed no difference in fermentation profile compared to the wild-type strain, while ldhL1 single deletion or ldhL1ldhL2 double deletion completely blocked L-lactic acid production. Complementation of ldhL1 in the above knockout strains restored fermentation profiles to those observed in the wild-type strain. This study demonstrates ldhL1 is crucial for L-lactic acid production and NADH balance in B. coagulans DSM1 and lays the fundamental for engineering the thermotolerant B. coagulans strain as a platform chemicals producer.

Batch fermentative production of lactic acid from green- sugarcane juices

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Liliana Serna Cock

2004-07-01

Full Text Available Juice from the CC85-92 variety of green (unburned sugar cane was tested as a suitable substrate in lactic-acid production. Fermentations were carried out with a homo-fermentative strain isolated from crops of the same variety of cane. Both the centrifugation pre-treatment and concentrated-nitrogen effects on substrate conversion, lactic-acid concentration and yield were evaluated. After a fermentation time of 48 h at 32° C with 5% of yeast extract as nitrogen source, 40,78 g/L of lactic-acid concentration, 0.58 g/g of product yield and 33% of substrate conversion were obtained. Centrifugation did not affect lactic acid production. Key words: Lactic acid, green sugar cane, Lactococcus lactis subs. lactis.

[Modeling of lactic acid fermentation of leguminous plant juices].

Science.gov (United States)

Shurkhno, R A; Validov, Sh Z; Boronin, A M; Naumova, R P

2006-01-01

Lactic acid fermentation of leguminous plant juices was modeled to provide a comparative efficiency assessment of the previously selected strains of lactic acid bacteria as potential components of starter cultures. Juices of the legumes fodder galega, red clover, and alfalfa were subjected to lactic acid fermentation in 27 variants of experiment. Local strains (Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, and Lactobacillus sp. RS 4) and the collection strain Lactobacillus plantarum BS 933 appeared the most efficient (with reference to the rate and degree of acidogenesis, ratio of lactic and acetic acids, and dynamics of microflora) in fermenting fodder galega juice; Lactobacillus sp. RS 1, Lactobacillus sp. RS 2, Lactobacillus sp. RS 3, Lactobacillus sp. RS 4, and L. plantarum BS 933 were the most efficient for red clover juice. Correction of alfalfa juice fermentation using the tested lactic acid bacterial strains appeared inefficient, which is explainable by its increased protein content and a low level of the acids produced during fermentation.

Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae.

Directory of Open Access Journals (Sweden)

Zheng Gong

Full Text Available Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

Investigation of Chemical Exchange at Intermediate Exchange Rates using a Combination of Chemical Exchange Saturation Transfer (CEST) and Spin-Locking methods (CESTrho)

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2011-01-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer (CEST) and T1ρ magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. PMID:22009759

Investigation of chemical exchange at intermediate exchange rates using a combination of chemical exchange saturation transfer (CEST) and spin-locking methods (CESTrho).

Science.gov (United States)

Kogan, Feliks; Singh, Anup; Cai, Keija; Haris, Mohammad; Hariharan, Hari; Reddy, Ravinder

2012-07-01

Proton exchange imaging is important as it allows for visualization and quantification of the distribution of specific metabolites with conventional MRI. Current exchange mediated MRI methods suffer from poor contrast as well as confounding factors that influence exchange rates. In this study we developed a new method to measure proton exchange which combines chemical exchange saturation transfer and T(1)(ρ) magnetization preparation methods (CESTrho). We demonstrated that this new CESTrho sequence can detect proton exchange in the slow to intermediate exchange regimes. It has a linear dependence on proton concentration which allows it to be used to quantitatively measure changes in metabolite concentration. Additionally, the magnetization scheme of this new method can be customized to make it insensitive to changes in exchange rate while retaining its dependency on solute concentration. Finally, we showed the feasibility of using CESTrho in vivo. This sequence is able to detect proton exchange at intermediate exchange rates and is unaffected by the confounding factors that influence proton exchange rates thus making it ideal for the measurement of metabolites with exchangeable protons in this exchange regime. Copyright © 2011 Wiley Periodicals, Inc.

A Glutamic Acid-Producing Lactic Acid Bacteria Isolated from Malaysian Fermented Foods

Science.gov (United States)

Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B.; Saari, Nazamid

2012-01-01

l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound. PMID:22754309

Bacillus coagulans MA-13: a promising thermophilic and cellulolytic strain for the production of lactic acid from lignocellulosic hydrolysate.

Science.gov (United States)

Aulitto, Martina; Fusco, Salvatore; Bartolucci, Simonetta; Franzén, Carl Johan; Contursi, Patrizia

2017-01-01

The transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed. A thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans , named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C. The above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto

New Poly(lactic acid) Active Packaging Composite Films Incorporated with Fungal Melanin

OpenAIRE

Łukasz Łopusiewicz; Filip Jędra; Małgorzata Mizielińska

2018-01-01

In this work, fungal melanin was used for the first time to prepare poly(lactic acid)-based composites. The films of various melanin concentrations (0.025%, 0.05% and 0.2% w/w) were prepared using an extrusion method. The mechanical, antioxidant, antimicrobial, water vapor and UV-Vis barrier properties, as well as available polyphenolics on the surface, were studied. FT-IR and Raman spectroscopy studies were carried out to analyze the chemical composition of the resulting films. The hydrophob...

Enhanced D-lactic acid production from renewable resources using engineered Lactobacillus plantarum.

Science.gov (United States)

Zhang, Yixing; Vadlani, Praveen V; Kumar, Amit; Hardwidge, Philip R; Govind, Revathi; Tanaka, Tsutomu; Kondo, Akihiko

2016-01-01

D-lactic acid is used as a monomer in the production of poly-D-lactic acid (PDLA), which is used to form heat-resistant stereocomplex poly-lactic acid. To produce cost-effective D-lactic acid by using all sugars derived from biomass efficiently, xylose-assimilating genes encoding xylose isomerase and xylulokinase were cloned into an L-lactate-deficient strain, Lactobacillus plantarum. The resulting recombinant strain, namely L. plantarum NCIMB 8826 ∆ldhL1-pLEM-xylAB, was able to produce D-lactic acid (at optical purity >99 %) from xylose at a yield of 0.53 g g(-1). Simultaneous utilization of glucose and xylose to produce D-lactic acid was also achieved by this strain, and 47.2 g L(-1) of D-lactic acid was produced from 37.5 g L(-1) glucose and 19.7 g L(-1) xylose. Corn stover and soybean meal extract (SBME) were evaluated as cost-effective medium components for D-lactic acid production. Optimization of medium composition using response surface methodology resulted in 30 % reduction in enzyme loading and 70 % reduction in peptone concentration. In addition, we successfully demonstrated D-lactic acid fermentation from corn stover and SBME in a fed-batch fermentation, which yielded 61.4 g L(-1) D-lactic acid with an overall yield of 0.77 g g(-1). All these approaches are geared to attaining high D-lactic acid production from biomass sugars to produce low-cost, highly thermostable biodegradable plastics.

Design of a chemical batch plant : a study of dedicated parallel lines with intermediate storage and the plant performance

OpenAIRE

Verbiest, Floor; Cornelissens, Trijntje; Springael, Johan

2016-01-01

Abstract: Production plants worldwide face huge challenges in satisfying high service levels and outperforming competition. These challenges require appropriate strategic decisions on plant design and production strategies. In this paper, we focus on multiproduct chemical batch plants, which are typically equipped with multiple production lines and intermediate storage tanks. First we extend the existing MI(N) LP design models with the concept of parallel production lines, and optimise the as...

L-lactic acid production from starch by simultaneous saccharification and fermentation in a genetically engineered Aspergillus oryzae pure culture.

Science.gov (United States)

Wakai, Satoshi; Yoshie, Toshihide; Asai-Nakashima, Nanami; Yamada, Ryosuke; Ogino, Chiaki; Tsutsumi, Hiroko; Hata, Yoji; Kondo, Akihiko

2014-12-01

Lactic acid is a commodity chemical that can be produced biologically. Lactic acid-producing Aspergillus oryzae strains were constructed by genetic engineering. The A. oryzae LDH strain with the bovine L-lactate dehydrogenase gene produced 38 g/L of lactate from 100g/L of glucose. Disruption of the wild-type lactate dehydrogenase gene in A. oryzae LDH improved lactate production. The resulting strain A. oryzae LDHΔ871 produced 49 g/L of lactate from 100g/L of glucose. Because A. oryzae strains innately secrete amylases, A. oryzae LDHΔ871 produced approximately 30 g/L of lactate from various starches, dextrin, or maltose (all at 100 g/L). To our knowledge, this is the first report describing the simultaneous saccharification and fermentation of lactate from starch using a pure culture of transgenic A. oryzae. Our results indicate that A. oryzae could be a promising host for the bioproduction of useful compounds such as lactic acid. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stability of the pyrethroid pesticide bifenthrin in milled wheat during thermal processing, yeast and lactic acid fermentation, and storage.

Science.gov (United States)

Dorđević, Tijana M; Šiler-Marinković, Slavica S; Ðurović, Rada D; Dimitrijević-Branković, Suzana I; Gajić Umiljendić, Jelena S

2013-10-01

Pesticide residues have become an unavoidable part of food commodities. In the context of increased interest for food processing techniques as a tool for reducing pesticide residues, it is interesting to study the potential loss of pesticides during lactic acid and yeast fermentation. In the present paper the effect of fermentation by Lactobacillus plantarum and Saccharomyces cerevisiae and storage on 23 °C on bifenthrin in wheat was investigated. In addition, the effect of sterilisation (applied in order to avoid contamination with wild microorganism strains, i.e. to determine the individual effects of used strains) on bifenthrin degradation was tested as well. No significant loss of bifenthrin was observed during storage, or after the sterilisation. During the lactic acid fermentation, reduction within wheat fortified with 0.5 mg kg(-1) was 42%, while quite lower within samples fortified with 2.5 mg kg(-1) , maximum 18%. In contrast, bifenthrin concentration was not reduced during yeast fermentation, as the reduction in fortified samples was in the range of spontaneous chemical degradation during incubation period. Possible bifenthrin contamination in wheat, in amounts over the maximum residue limits, could not be reduced by sterilisation or by yeast fermentation, but lactic acid fermentation could be an effective tool for minimising residual contamination. © 2013 Society of Chemical Industry.

Influence of sodium chloride, pH, and lactic acid bacteria on anaerobic lactic acid utilization during fermented cucumber spoilage.

Science.gov (United States)

Johanningsmeier, Suzanne D; Franco, Wendy; Perez-Diaz, Ilenys; McFeeters, Roger F

2012-07-01

Cucumbers are preserved commercially by natural fermentations in 5% to 8% sodium chloride (NaCl) brines. Occasionally, fermented cucumbers spoil after the primary fermentation is complete. This spoilage has been characterized by decreases in lactic acid and a rise in brine pH caused by microbial instability. Objectives of this study were to determine the combined effects of NaCl and pH on fermented cucumber spoilage and to determine the ability of lactic acid bacteria (LAB) spoilage isolates to initiate lactic acid degradation in fermented cucumbers. Cucumbers fermented with 0%, 2%, 4%, and 6% NaCl were blended into slurries (FCS) and adjusted to pH 3.2, 3.8, 4.3, and 5.0 prior to centrifugation, sterile-filtration, and inoculation with spoilage organisms. Organic acids and pH were measured initially and after 3 wk, 2, 6, 12, and 18 mo anaerobic incubation at 25 °C. Anaerobic lactic acid degradation occurred in FCS at pH 3.8, 4.3, and 5.0 regardless of NaCl concentration. At pH 3.2, reduced NaCl concentrations resulted in increased susceptibility to spoilage, indicating that the pH limit for lactic acid utilization in reduced NaCl fermented cucumbers is 3.2 or lower. Over 18 mo incubation, only cucumbers fermented with 6% NaCl to pH 3.2 prevented anaerobic lactic acid degradation by spoilage bacteria. Among several LAB species isolated from fermented cucumber spoilage, Lactobacillus buchneri was unique in its ability to metabolize lactic acid in FCS with concurrent increases in acetic acid and 1,2-propanediol. Therefore, L. buchneri may be one of multiple organisms that contribute to development of fermented cucumber spoilage. Microbial spoilage of fermented cucumbers during bulk storage causes economic losses for producers. Current knowledge is insufficient to predict or control these losses. This study demonstrated that in the absence of oxygen, cucumbers fermented with 6% sodium chloride to pH 3.2 were not subject to spoilage. However, lactic acid was degraded

Ultrasonic Monitoring of the Progress of Lactic Acid Fermentation

Science.gov (United States)

Masuzawa, Nobuyoshi; Kimura, Akihiro; Ohdaira, Etsuzo

2003-05-01

Promotion of lactic acid fermentation by ultrasonic irradiation has been attempted. It is possible to determine the progress of fermentation and production of a curd, i.e., yoghurt and or kefir, by measuring acidity using a pH meter. However, this method is inconvenient and indirect for the evaluation of the progress of lactic acid fermentation under anaerobic condition. In this study, an ultrasonic monitoring method for evaluating the progress of lactic acid fermentation was examined.

Comparative genomics of the lactic acid bacteria

Energy Technology Data Exchange (ETDEWEB)

Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

2006-06-01

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

Monitoring the Evolution of Major Chemical Compound in Dairy Products During Shelf-Life by FTIR

Directory of Open Access Journals (Sweden)

Adriana Păucean

2014-11-01

Full Text Available Fourier-transform infrared (FTIR spectroscopy is considered to be a comprehensive and sensitive method to characterize the chemical composition and for detection of molecular changes in different samples. In this study, FTIRspectroscopy  was employed as an rapid and low-cost technique in order to characterize the FTIR spectra and identify appropriate spectral regions for dairy product fermented by a lactic culture consisting by species of Lactococcus lactis and Leuconostoc mesenteroides. A second objective was to monitore the key chemical compounds (lactose, lactic acid, flavors during fermentation and refrigerated storage (1-21 days, at 4-6°C. By FT-IR fingerprint during fermentation we identified changes of the spectra pattern with specific increasing or decreasing peaks for lactose, lactic acid, esters, aromatic compounds, aminoacids, fatty acids. Also the technique was able to identify chemical compounds involved in the microbial activity such as phosphates and phosphorylated carbohydrates during fermentation and dairy product shelf-life. All the major chemical compounds recorded significant increaments during fermentation and refrigerated storage comparing with the raw milk.

The genomic analysis of lactic acidosis and acidosis response in human cancers.

Directory of Open Access Journals (Sweden)

Julia Ling-Yu Chen

2008-12-01

Full Text Available The tumor microenvironment has a significant impact on tumor development. Two important determinants in this environment are hypoxia and lactic acidosis. Although lactic acidosis has long been recognized as an important factor in cancer, relatively little is known about how cells respond to lactic acidosis and how that response relates to cancer phenotypes. We develop genome-scale gene expression studies to dissect transcriptional responses of primary human mammary epithelial cells to lactic acidosis and hypoxia in vitro and to explore how they are linked to clinical tumor phenotypes in vivo. The resulting experimental signatures of responses to lactic acidosis and hypoxia are evaluated in a heterogeneous set of breast cancer datasets. A strong lactic acidosis response signature identifies a subgroup of low-risk breast cancer patients having distinct metabolic profiles suggestive of a preference for aerobic respiration. The association of lactic acidosis response with good survival outcomes may relate to the role of lactic acidosis in directing energy generation toward aerobic respiration and utilization of other energy sources via inhibition of glycolysis. This "inhibition of glycolysis" phenotype in tumors is likely caused by the repression of glycolysis gene expression and Akt inhibition. Our study presents a genomic evaluation of the prognostic information of a lactic acidosis response independent of the hypoxic response. Our results identify causal roles of lactic acidosis in metabolic reprogramming, and the direct functional consequence of lactic acidosis pathway activity on cellular responses and tumor development. The study also demonstrates the utility of genomic analysis that maps expression-based findings from in vitro experiments to human samples to assess links to in vivo clinical phenotypes.

Process for the preparation of lactic acid and glyceric acid

Science.gov (United States)

Jackson, James E [Haslett, MI; Miller, Dennis J [Okemos, MI; Marincean, Simona [Dewitt, MI

2008-12-02

Hexose and pentose monosaccharides are degraded to lactic acid and glyceric acid in an aqueous solution in the presence of an excess of a strongly anionic exchange resin, such as AMBERLITE IRN78 and AMBERLITE IRA400. The glyceric acid and lactic acid can be separated from the aqueous solution. Lactic acid and glyceric acid are staple articles of commerce.

The impact of lactic acid bacteria on sourdough fermentation

Directory of Open Access Journals (Sweden)

Savić Dragiša S.

2005-01-01

Full Text Available The baking of sourdough breads represents one of the oldest biotechnological processes. Despite traditionality, sourdough bread has great potential because of its benefits. Sourdough is a mixture of flour and water that is dominated by a complex microflora composed of yeasts and lactic acid bacteria that are crucial in the preparation of bread dough. Lactic acid bacteria cause acidification by producing lactic acid that increases the shelf life of bread by preventing the growth of undesirable microorganisms and affects the nutritional value of bread by increasing the availability of minerals. In addition to these advantages, the use of sourdough fermentation also improves dough machinability, breadcrumb structure and the characteristic flavour of bread. Lactic acid bacteria in sourdough fermentation are well known representing both homofermentative and heterofermentative bacteria. They may originate from selected natural contaminants in the flour or from a starter culture containing one or more known species of lactic acid bacteria. Sourdough can be cultivated in bakeries or obtained from commercial suppliers. However, many bakeries in Europe still use spontaneously fermented sourdoughs, which have been kept metabolically active for decades by the addition of flour and water at regular intervals. The impact of lactic acid bacteria on sourdough fermentation and their influence on dough and bread quality was discussed on the basis of research and literature data.

Exploitation of vegetables and fruits through lactic acid fermentation.

Science.gov (United States)

Di Cagno, Raffaella; Coda, Rossana; De Angelis, Maria; Gobbetti, Marco

2013-02-01

Lactic acid fermentation represents the easiest and the most suitable way for increasing the daily consumption of fresh-like vegetables and fruits. Literature data are accumulating, and this review aims at describing the main features of the lactic acid bacteria to be used for fermentation. Lactic acid bacteria are a small part of the autochthonous microbiota of vegetables and fruits. The diversity of the microbiota markedly depends on the intrinsic and extrinsic parameters of the plant matrix. Notwithstanding the reliable value of the spontaneous fermentation to stabilize and preserve raw vegetables and fruits, a number of factors are in favour of using selected starters. Two main options may be pursued for the controlled lactic acid fermentation of vegetables and fruits: the use of commercial/allochthonous and the use of autochthonous starters. Several evidences were described in favour of the use of selected autochthonous starters, which are tailored for the specific plant matrix. Pro-technological, sensory and nutritional criteria for selecting starters were reported as well as several functional properties, which were recently ascribed to autochthonous lactic acid bacteria. The main features of the protocols used for the manufacture of traditional, emerging and innovative fermented vegetables and fruits were reviewed. Tailored lactic acid bacteria starters completely exploit the potential of vegetables and fruits, which enhances the hygiene, sensory, nutritional and shelf life properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Metformin-associated lactic acidosis mimicking ischaemic bowel.

Science.gov (United States)

Ali, Sajjad; Labuschagne, Heloise; Azarov, Nickolay; Hindi, Zakaria; Oud, Lavi

2018-02-01

Metformin-associated lactic acidosis (MALA) is a rare complication among patients who are diabetic, commonly presenting with non-specific findings, and developing mostly among those with other risk factors for lactic acidosis. We report the development of MALA in a 67-year-old man with diabetes who presented with progressive abdominal pain and bloody diarrhoea. On presentation the patient was in shock, with signs suggestive of peritonitis, and with severe lactic acidosis, renal failure and non-specific findings on abdominal CT. Neither the patient nor family could provide details of his home pharmaceuticals. Circulatory resuscitation with intravenous crystalloids and vasopressors was commenced, along with empiric broad-spectrum antibiotics. Emergent laparotomy did not show pathological findings. Emergent haemodialysis, initiated postoperatively, resulted in rapid resolution of shock and lactic acidosis. A list of patient's medications, provided afterwards by the family, included metformin. Microbiological studies remained negative and renal function normalised by the time of patient's hospital discharge after 9 days. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Fermentative lactic acid production from coffee pulp hydrolysate using Bacillus coagulans at laboratory and pilot scales.

Science.gov (United States)

Pleissner, Daniel; Neu, Anna-Katrin; Mehlmann, Kerstin; Schneider, Roland; Puerta-Quintero, Gloria Inés; Venus, Joachim

2016-10-01

In this study, the lignocellulosic residue coffee pulp was used as carbon source in fermentative l(+)-lactic acid production using Bacillus coagulans. After thermo-chemical treatment at 121°C for 30min in presence of 0.18molL(-1) H2SO4 and following an enzymatic digestion using Accellerase 1500 carbon-rich hydrolysates were obtained. Two different coffee pulp materials with comparable biomass composition were used, but sugar concentrations in hydrolysates showed variations. The primary sugars were (gL(-1)) glucose (20-30), xylose (15-25), sucrose (5-11) and arabinose (0.7-10). Fermentations were carried out at laboratory (2L) and pilot (50L) scales in presence of 10gL(-1) yeast extract. At pilot scale carbon utilization and lactic acid yield per gram of sugar consumed were 94.65% and 0.78gg(-1), respectively. The productivity was 4.02gL(-1)h(-1). Downstream processing resulted in a pure formulation containing 937gL(-1)l(+)-lactic acid with an optical purity of 99.7%. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Lactic acid fermentation of cassava dough into agbelima.

Science.gov (United States)

Amoa-Awua, W K; Appoh, F E; Jakobsen, M

1996-08-01

The souring of cassava dough during fermentation into the fermented cassava meal, agbelima, was investigated. Four different types of traditional inocula were used to ferment the dough and increases in titrable acidity expressed as lactic acid from 0.31-0.38 to 0.78-0.91% (w/w) confirmed the fermentation to be a process of acidification. The microflora of all inocula and fermenting dough contained high counts of lactic acid bacteria, 10(8)-10(9) cfu/g in all inocula and 10(7)-10(8), 10(8)-10(9) and 10(9) cfu/g at 0, 24 and 48 h in all fermentations. Lactobacillus plantarum was the dominant species of lactic acid bacteria during all types of fermentation accounting for 51% of 171 representative isolates taken from various stages of fermentation. Other major lactic acid bacteria found were Lactobacillus brevis, 16%, Leuconostoc mesenteroides, 15% and some cocci including Streptococcus spp. whose numbers decreased with fermentation time. The lactic acid bacteria were responsible for the souring of agbelima through the production of lactic acid. All L. plantarum, L. brevis and L. mesenteroides isolates examined demonstrated linamarase as well as other enzymatic activities but did not possess tissue degrading enzymes like cellulase, pectin esterase and polygalacturonase. The aroma profile of agbelima did not vary with the type of inoculum used and in all samples the build-up of aroma compounds were dominated by a non-identified low molecular weight alcohol, 1-propanol, isoamyl alcohol, ethyl acetate, 3-methyl-1-butanol and acetoin. Substantial reductions occurred in the levels of cyanogenic compounds present in cassava during fermentation into agbelima and detoxification was enhanced by the use of inoculum.

D-Lactic acid biosynthesis from biomass-derived sugars via Lactobacillus delbrueckii fermentation.

Science.gov (United States)

Zhang, Yixing; Vadlani, Praveen V

2013-12-01

Poly-lactic acid (PLA) derived from renewable resources is considered to be a good substitute for petroleum-based plastics. The number of poly L-lactic acid applications is increased by the introduction of a stereocomplex PLA, which consists of both poly-L and D-lactic acid and has a higher melting temperature. To date, several studies have explored the production of L-lactic acid, but information on biosynthesis of D-lactic acid is limited. Pulp and corn stover are abundant, renewable lignocellulosic materials that can be hydrolyzed to sugars and used in biosynthesis of D-lactic acid. In our study, saccharification of pulp and corn stover was done by cellulase CTec2 and sugars generated from hydrolysis were converted to D-lactic acid by a homofermentative strain, L. delbrueckii, through a sequential hydrolysis and fermentation process (SHF) and a simultaneous saccharification and fermentation process (SSF). 36.3 g L(-1) of D-lactic acid with 99.8 % optical purity was obtained in the batch fermentation of pulp and attained highest yield and productivity of 0.83 g g(-1) and 1.01 g L(-1) h(-1), respectively. Luedeking-Piret model described the mixed growth-associated production of D-lactic acid with a maximum specific growth rate 0.2 h(-1) and product formation rate 0.026 h(-1), obtained for this strain. The efficient synthesis of D-lactic acid having high optical purity and melting point will lead to unique stereocomplex PLA with innovative applications in polymer industry.

Spectroscopic studies of neutral and chemically oxidized species of β-carotene, lycopene and norbixin in CH{sub 2}Cl{sub 2}: Fluorescence from intermediate compounds

Energy Technology Data Exchange (ETDEWEB)

Alwis, D.D.D.H [Department of Chemistry, The Open University of Sri Lanka, Nawala (Sri Lanka); Department of Chemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka); Chandrika, U.G. [Department of Biochemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka); Jayaweera, P.M., E-mail: pradeep@sjp.ac.lk [Department of Chemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka)

2015-02-15

Radical cations, dications and oxidized intermediate species of three carotenoids, namely, β-carotene, lycopene and norbixin, were generated in CH{sub 2}Cl{sub 2} solutions via chemical oxidation using anhydrous FeCl{sub 3}. UV–vis, fluorescence and fluorescence-excitation spectroscopic studies were performed to understand and compare the nature of intermediate species generated during the chemical oxidation process and subsequent degradation. The intense emission observed at 550 nm can be assigned to the S{sub 2}→S{sub 0} (1{sup 1}B{sub u}→1{sup 1}A{sub g}) transition of the carotenoid molecules. The 350 nm excitation during the oxidation process for β-carotene, lycopene and norbixin exhibit intense fluorescence peaks at 492 nm, 493 nm and 500 nm, respectively. These peaks are assigned to intermediate peroxy/epoxy compounds of the three molecules that are formed with molecular oxygen prior to the formation of oxidized short-chain stable compounds. - Highlights: • Fluorescence and UV–vis studies on β-carotene, lycopene and norbixin. • Oxidation, induced by FeCl{sub 3} in CH{sub 2}Cl{sub 2} shows blue shifted fluorescence peaks. • Fluorescence peaks were assigned to intermediate peroxy/epoxy forms of carotenoids. • The D0→D3 transition of radical cations are observed in the near IR region.

9th International Symposium on Lactic Acid Bacteria

NARCIS (Netherlands)

Kuipers, Oscar P.; Poolman, Berend; Hugenholtz, Jeroen

What’s new in the field of lactic acid bacteria? The 9th International Symposium on Lactic Acid Bacteria (LAB9) will take place 31 August to 4 September 2008 in Egmond aan Zee, The Netherlands. Traditionally, the triannual LAB symposium focuses on the themes of genetics, physiology, and applications

Bacteriocins and lactic acid bacteria - a minireview | Savadogo ...

African Journals Online (AJOL)

Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of biopreservation practised by mankind. Bacterial antagonism has been recognized for over a century but in recent years this phenomenon has received more scientific attention, particulary in the use of various strains of lactic acid bacteria.

Lactic acid production from xylose by engineered Saccharomyces cerevisiae without PDC or ADH deletion.

Science.gov (United States)

Turner, Timothy L; Zhang, Guo-Chang; Kim, Soo Rin; Subramaniam, Vijay; Steffen, David; Skory, Christopher D; Jang, Ji Yeon; Yu, Byung Jo; Jin, Yong-Su

2015-10-01

Production of lactic acid from renewable sugars has received growing attention as lactic acid can be used for making renewable and bio-based plastics. However, most prior studies have focused on production of lactic acid from glucose despite that cellulosic hydrolysates contain xylose as well as glucose. Microbial strains capable of fermenting both glucose and xylose into lactic acid are needed for sustainable and economic lactic acid production. In this study, we introduced a lactic acid-producing pathway into an engineered Saccharomyces cerevisiae capable of fermenting xylose. Specifically, ldhA from the fungi Rhizopus oryzae was overexpressed under the control of the PGK1 promoter through integration of the expression cassette in the chromosome. The resulting strain exhibited a high lactate dehydrogenase activity and produced lactic acid from glucose or xylose. Interestingly, we observed that the engineered strain exhibited substrate-dependent product formation. When the engineered yeast was cultured on glucose, the major fermentation product was ethanol while lactic acid was a minor product. In contrast, the engineered yeast produced lactic acid almost exclusively when cultured on xylose under oxygen-limited conditions. The yields of ethanol and lactic acid from glucose were 0.31 g ethanol/g glucose and 0.22 g lactic acid/g glucose, respectively. On xylose, the yields of ethanol and lactic acid were substrates.

Heme and menaquinone induced electron transport in lactic acid bacteria

OpenAIRE

Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen

2009-01-01

Abstract Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacill...

Lactic Acidosis ID Diabetics

African Journals Online (AJOL)

shock, chronic hepatic disease and chronic renal disease. In some the ... infection, or minor alcohol ingestion. The purpose of ..... Liver disease or liver anoxia will result in lactic acid ... lactate."'" The contributory effect of alcohol is important.

Lactic acid fermentation of crude sorghum extract

Energy Technology Data Exchange (ETDEWEB)

Samuel, W.A.; Lee, Y.Y.; Anthony, W.B.

1980-04-01

Crude extract from sweet sorghum supplemented with vetch juice was utilized as the carbohydrate source for fermentative production of lactic acid. Fermentation of media containing 7% (w/v) total sugar was completed in 60-80 hours by Lactobacillus plantarum, product yield averaging 85%. Maximum acid production rates were dependent on pH, initial substrate distribution, and concentration, the rates varying from 2 to 5 g/liter per hour. Under limited medium supplementation the lactic acid yield was lowered to 67%. The fermented ammoniated product contained over eight times as much equivalent crude protein (N x 6.25) as the original medium. Unstructured kinetic models were developed for cell growth, lactic acid formation, and substrate consumption in batch fermentation. With the provision of experimentally determined kinetic parameters, the proposed models accurately described the fermentation process. 15 references.

Effect of probiotic thermotolerant lactic bacteria on the physicochemical, microbiological and sensorial characteristics of cooked meat batters

Directory of Open Access Journals (Sweden)

Nallely Saucedo-Briviesca

2017-07-01

Full Text Available Some lactic acid bacteria (LAB can overexpress heat shock proteins and thus survive the heat treatment of meat products. The objective of this work was the effect of probiotic thermotolerant lactic acid bacteria on the physicochemical, microbiological and sensorial characteristics in a meat batter. Two thermotolerant probiotic lactic bacteria were used: Pediococcus pentosaceus and Enterococcus faecium, which were inoculated to 5% in a meat batter, another batter was made with the mixture of both strains; a batter without bacteria was the control. Both physicochemical and microbiological analyses were performed at day 1, 6, 13 and 16. At day 1 a discriminatory sensory evaluation was performed. The results show that the stability to cooking, expressible moisture, hardness and cohesion increased during storage in the batters inoculated with the 2 strains of LAB. The LAB increased in the inoculated meat batters and the coliforms decreased overall, when the strain mixture was used, the inhibition was total at day 6. Sensory analysis showed that judges detect when E. faecium are inoculated. Thermotolerant BALs can be used as functional ingredients in meat batters and improve physical-chemical and microbiological characteristics.

Composition dependence of the synergistic effect of nucleating agent and plasticizer in poly(lactic acid: A Mixture Design study

Directory of Open Access Journals (Sweden)

M. K. Fehri

2016-04-01

Full Text Available Blends consisting of commercial poly(lactic acid (PLA, poly(lactic acid oligomer (OLA8 as plasticizer and a sulfonic salt of a phthalic ester and poly(D-lactic acid as nucleating agents were prepared by melt extrusion, following a Mixture Design approach, in order to systematically study mechanical and thermal properties as a function of composition. The full investigation was carried out by differential scanning calorimetry (DSC, dynamic mechanical thermal analysis (DMTA and tensile tests. The crystallization half-time was also studied at 105 °C as a function of the blends composition. A range of compositions in which the plasticizer and the nucleation agent minimized the crystallization half-time in a synergistic way was clearly identified thanks to the application of the Mixture Design approach. The results allowed also the identification of a composition range to maximize the crystallinity developed during the rapid cooling below glass transition temperature in injection moulding, thus allowing an easier processing of PLA based materials. Moreover the mechanical properties were discussed by correlating them to the chemical structural features and thermal behaviour of blends.

Flow cytometric assessment of viability of lactic acid bacteria

NARCIS (Netherlands)

Bunthof, C.J.; Bloemen, K.; Breeuwer, P.; Rombouts, F.M.; Abee, T.

2001-01-01

The viability of lactic acid bacteria is crucial for their applications as dairy starters and as probiotics. We investigated the usefulness of flow cytometry (FCM) for viability assessment of lactic acid bacteria. The esterase substrate carboxyfluorescein diacetate (cFDA) and the dye exclusion DNA

Screening and identification of lactic acid bacteria isolated from ...

African Journals Online (AJOL)

The lactic acid bacteria (LAB) isolated from sorghum (Sorghum bicolor. L.) silage were identified during different periods of evolution of sorghum silage in west Algeria. Morphological, physiological, biochemical and technological techniques were used to characterize lactic acid bacteria isolates. A total number of 27 ...

Biodegradable poly(lactic acid)

Indian Academy of Sciences (India)

The fabrication of biodegradable poly(lactic acid) (PLA) microspheres containing total alkaloids of Caulis sinomenii was investigated. The formation, diameter, morphology and properties of the microspheres were characterized using Fourier transform infrared spectroscopy (FT–IR), laser particle size analyser and scanning ...

Risk of lactic acidosis in type 2 diabetes patients using metformin

DEFF Research Database (Denmark)

Aharaz, Abdellatif; Pottegård, Anton; Henriksen, Daniel Pilsgaard

2018-01-01

risk of lactic acidosis associated with metformin treatment. Methods This is a population-based combined cohort and case-control study among patients with type 2 diabetes mellitus who were acutely admitted with lactic acidosis at Odense University Hospital, Denmark; in the period from 1st June 2009...... to 1st October 2013. The patients included as cases were all acutely hospitalized with lactic acidosis (pH 2.0 mmol/l). For each case, we identified 24 age- and sex-matched controls sampled from the same cohort with type 2 diabetes mellitus. The use of metformin identified by using......Background Metformin constitutes first-line treatment of type 2 diabetes mellitus. It is presumed to have lactic acidosis as a dangerous, but rare, side effect. Objectives To estimate the incidence rate of lactic acidosis in patients with type 2 diabetes mellitus as well as to estimate the relative...

Kinetics and adsorption isotherm of lactic acid from fermentation broth onto activated charcoal

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Seankham Soraya

2017-01-01

Full Text Available Activated charcoal was applied for the recovery of lactic acid in undissociated form from fermentation broth. Lactic acid was obtained from the fermentation of Lactobacillus casei TISTR 1340 using acid hydrolyzed Jerusalem artichoke as a carbon source. The equilibrium adsorption isotherm and kinetics for the lactic acid separation were investigated. The experimental data for lactic acid adsorption from fermentation broth were best described by the Freundlich isotherm and the pseudo-second order kinetics with R2 values of 0.99. The initial adsorption rate was 41.32 mg/g⋅min at the initial lactic acid concentration of 40 g/L.

The relationships between consumer liking, sensory and chemical attributes of Vitis vinifera L. cv. Pinotage wines elaborated with different Oenococcus oeni starter cultures

DEFF Research Database (Denmark)

Malherbe, Sulette; Menichelli, Elena; du Toit, Maret

2013-01-01

BackgroundMalolactic fermentation (MLF) mediated by lactic acid bacteria (LAB) has been shown to modulate chemical and sensory attributes of wine. This study investigated the relation between consumer liking, chemical and sensory attributes of Vitis vinifera L. cv. Pinotage wines that were made o...... attributes can influence consumer liking. Selection of an MLF starter culture can thus potentially be used to develop specific wine styles. (c) 2013 Society of Chemical Industry......BackgroundMalolactic fermentation (MLF) mediated by lactic acid bacteria (LAB) has been shown to modulate chemical and sensory attributes of wine. This study investigated the relation between consumer liking, chemical and sensory attributes of Vitis vinifera L. cv. Pinotage wines that were made...... over two vintages by four different lactic acid Oenococcus oeni starter cultures as well as a control treatment where MLF was prevented. ResultsDescriptive analysis showed that the sensory attributes buttery, caramel, vegetative flavour, fruity and nutty aroma differed significantly between the wines...

Lactic Acidosis in a Patient with Type 2 Diabetes Mellitus.

Science.gov (United States)

Weisberg, Lawrence S

2015-08-07

Lactic acidosis occurs when lactate production exceeds its metabolism. There are many possible causes of lactic acidosis, and in any given patient, several causes may coexist. This Attending Rounds presents a case in point. Metformin's role in the pathogenesis of lactic acidosis in patients with diabetes mellitus is complex, as the present case illustrates. The treatment of lactic acidosis is controversial, except for the imperative to remedy its underlying cause. The use of sodium bicarbonate to treat the often alarming metabolic derangements may be quite efficacious in that regard but is of questionable benefit to patients. Renal replacement therapies (RRTs) have particular appeal in this setting for a variety of reasons, but their effect on clinical outcomes is untested. Copyright © 2015 by the American Society of Nephrology.

Copper (II) addition to accelerate lactic acid production from co-fermentation of food waste and waste activated sludge: Understanding of the corresponding metabolisms, microbial community and predictive functional profiling.

Science.gov (United States)

Ye, Tingting; Li, Xiang; Zhang, Ting; Su, Yinglong; Zhang, Wenjuan; Li, Jun; Gan, Yanfei; Zhang, Ai; Liu, Yanan; Xue, Gang

2018-03-20

Bio-refinery of food waste and waste activated sludge to high value-added chemicals, such as lactic acid, has attracted particular interest in recent years. In this paper, the effect of copper (II) dosing to the organic waste fermentation system on lactic acid production was evaluated, which proved to be a promising method to stimulate high yield of lactic acid (77.0% higher than blank) at dosage of 15 μM-Cu 2+ /g VSS. As mechanism study suggested, copper addition enhanced the activity of α-glycosidase and glycolysis, which increased the substrate for subsequent acidification; whereas, the high dosage (70 μM-Cu 2+ /g VSS) inhibited the conversion of lactic acid to VFA, thus stabilized lactic acid concentration. Microbial community study revealed that small amount of copper (II) at 15 μM/g VSS resulted in the proliferation of Lactobacillus to 82.6%, which mainly produced lactic acid. Finally, the variation of functional capabilities implied that the proposed homeostatic system II was activated at relatively low concentration of copper. Meanwhile, membrane transport function and carbohydrate metabolism were also strengthened. This study provides insights into the effect of copper (II) on the enhancement of lactic acid production from co-fermentation of food waste and waste activated sludge. Copyright © 2018 Elsevier Ltd. All rights reserved.

The examination of parameters for lactic acid fermentation and nutritive value of fermented juice of beetroot, carrot and brewer’s yeast autolysate

Directory of Open Access Journals (Sweden)

MILAN MAKSIMOVIC

2004-09-01

Full Text Available The conditions for lactic acid fermentation based on a mixture of beetoot juice (Beta vulgaris L. and carrot juice (Daucus carota L. and different content of brewer’s yeast autolysate with Lactobacillus plantarum A112 and with Lactobacillus acidophilus NCDO 1748 has been studied. Both cultures showed good biochemical activity in these mixtures. The production of lactic acid has been stimulated using a higher content of brewer’s yeast autolysate. In these mixtures, L. plantarum A112 showed better growth and lactic acid production than L. acidophilus NCDO 1748. From the data obtained through chemical analyses of the fermented products, it can be seen that the mixture of beetroot and carrot juice and brewer’s yeast autolysate is richer in minerals (Ca, P, Fe and b-carotene than fermented beetroot juice with the same content of brewer’s yeast autolysate.

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

NARCIS (Netherlands)

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

2016-01-01

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

Coupling two sizes of CSTR-type bioreactors for sequential lactic acid and xylitol production from hemicellulosic hydrolysates of vineshoot trimmings.

Science.gov (United States)

Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Domínguez, José Manuel

2012-02-15

This study develops a system for the efficient valorisation of hemicellulosic hydrolysates of vineshoot trimmings. By connecting two reactors of 2L and 10L, operational conditions were set up for the sequential production of lactic acid and xylitol in continuous fermentation, considering the dependence of the main metabolites and fermentation parameters on the dilution rate. In the first bioreactor, Lactobacillus rhamnosus consumed all the glucose to produce lactic acid at 31.5°C, with 150rpm and 1L of working volume as the optimal conditions. The residual sugars were employed for the xylose to xylitol bioconversion by Debaryomyces hansenii in the second bioreactor at 30°C, 250rpm and an air-flow rate of 2Lmin(-1). Several steady states were reached at flow rates (F) in the range of 0.54-5.33mLmin(-1), leading to dilution rates (D) ranging from 0.032 to 0.320h(-1) in Bioreactor 1 and from 0.006 to 0.064h(-1) in Bioreactor 2. The maximum volumetric lactic acid productivity (Q(P LA)=2.908gL(-1)h(-1)) was achieved under D=0.266h(-1) (F=4.44mLmin(-1)); meanwhile, the maximum production of xylitol (5.1gL(-1)), volumetric xylitol productivity (Q(P xylitol)=0.218gL(-1)h(-1)), volumetric rate of xylose consumption (Q(S xylose)=0.398gL(-1)h(-1)) and product yield (0.55gg(-1)) were achieved at an intermediate dilution rate of 0.043h(-1) (F=3.55mLmin(-1)). Under these conditions, ethanol, which was the main by-product of the fermentation, was produced in higher amounts (1.9gL(-1)). Finally, lactic acid and xylitol were effectively recovered by conventional procedures. Copyright © 2011 Elsevier B.V. All rights reserved.

Materials and methods for efficient lactic acid production

Science.gov (United States)

Zhou, Shengde; Ingram, Lonnie O& #x27; Neal; Shanmugam, Keelnatham T; Yomano, Lorraine; Grabar, Tammy B; Moore, Jonathan C

2013-04-23

The present invention provides derivatives of Escherichia coli constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.

Metformin-associated lactic acidosis in a peritoneal dialysis patient

Directory of Open Access Journals (Sweden)

Najlaa Almaleki

2015-01-01

Full Text Available Metformin is one of the commonly used drugs in type-2 diabetes mellitus. It reduces glucose levels by increasing insulin sensitivity, reducing hepatic glucose release and increasing muscle uptake. One of the serious complications associated with metformin use is lactic acidosis, and it is associated with high morbidity and mortality. This is more likely to happen in patients with renal failure due to reduced clearance. International guidelines recommend discontinuing metformin in advanced renal failure. We report a case of metformin-associated lactic acidosis in a patient with end-stage renal disease on peritoneal dialysis. The patient presented with severe lactic acidosis, which was successfully treated with hemodialysis.

Salt-inducible promoter derivable from a lactic acid bacterium, and its use in a lactic acid bacterium for production of a desired protein

NARCIS (Netherlands)

Sanders, Jan Willem; Kok, Jan; Venema, Gerard; Ledeboer, Adrianus Marinus

1998-01-01

The invention provides a salt-inducible promoter present in SEQ ID NO: 10 and derivable from a lactic acid bacterium in isolation from the coding sequence normally controlled by said promoter in a wild-type lactic acid bacterium, with modifications and important parts thereof. Also provided are a

Topological characterization of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites

Science.gov (United States)

Bhat, A. H.; Dasan, Y. K.; Khan, Ihsan Ullah; Ahmad, Faiz; Ayoub, Muhammad

2016-11-01

This study was conducted to evaluate the morphological and barrier properties of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites. Nanocrystalline cellulose was isolated from waste oil palm empty fruit bunch fiber using Sulphuric acid hydrolysis. Chemical modifications of nanocrystalline cellulose was performed to allow good compatibilization between fiber and the polymer matrices and also to improve dispersion of fillers. Bionanocomposite materials were produced from these nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) using solvent casting and evaporation techniques. The properties of extracted nanocrystalline cellulose were examined using FT-IR spectroscopy, X-ray diffractometer, TEM and AFM. Besides that, the properties of bionanocomposites were examined through FESEM and oxygen permeability properties analysis. Better barrier and morphological properties were obtained for nanocrystalline cellulose reinforced bionanocomposites than for neat polymer blend.

Trauma triggering thyrotoxic crisis with lactic acidosis

Directory of Open Access Journals (Sweden)

Jennifer S Prosser

2015-01-01

Full Text Available Thyrotoxic crisis (TC is defined as a life-threatening exacerbation of the hyperthyroid state that causes multiple autonomic and metabolic disturbances. It is considered to be an endocrine emergency that must be urgently diagnosed and treated. We describe a case of TC precipitated by trauma with a resultant lactic acidosis. The patient is a 24-year-old male with a history of hyperthyroidism who presented to the emergency department following a motor vehicle accident. The patient was initially tachycardic and hypertensive, however, was afebrile. Initial laboratory analysis showed an anion gap of 26, lactic acid 7.6, free T4 5.61 and thyroid stimulating hormone < 0.015. A diagnosis of TC was made, and he was treated with intravenous fluids, propranolol, and methimazole with improvement of tachycardia and lactic acidosis. We discuss the features of this case, which reviews the presentations of TC as well as its metabolic sequelae.

Enzymatic synthesis of 11C-pyruvic acid and 11C-L-lactic acid

International Nuclear Information System (INIS)

Cohen, M.B.; Spolter, L.; Chang, C.C.; Cook, J.S.; Macdonald, N.S.

1980-01-01

L-Lactic acid is formed as the end product of glycolysis under anaerobic conditions in all cells, but this reaction is of special significance in the myocardium. L-Lactic acid is reversibly formed from and is in equilibrium with myocardial pyruvic acid, which is its sole metabolic pathway. 11 C-Pyruvic acid is synthesized from 11 C carbon dioxide using pyruvate-ferredoxin oxidoreductase and coenzymes. The 11 C-pyruvic acid is then converted to 11 -L-lactic acid by lactic acid dehydrogenase. The availability of 11 C-pyruvic acid and 11 C-L-lactic acid will permit the in vivo investigation of lactate metabolism. (author)

Laboratory studies of Aedes aegypti (L.) attraction to ketones, sulfides and primary chloroalkanes tested alone and in combination with l-lactic acid

Science.gov (United States)

The attraction of female Aedes aegypti to single compounds and binary compositions comprised of L-lactic acid and an additional saturated compound from a set of ketones, sulfides, and chloroalkanes was studied using a triple-cage dual-port olfactometer. These chemical classes were studied because o...

A case of lactic acidosis complicating assessment and management of asthma

Directory of Open Access Journals (Sweden)

Veenith Tonny V

2008-04-01

Full Text Available Abstract Introduction Lactic acidosis often occurs in severely unwell patients presenting to Accident and Emergency. It is commonly associated with either hypoxia or decreased tissue perfusion secondary due to cardiovascular collapse or sepsis. Case presentation We present a case of severe lactic acidosis in the presence of normal tissue perfusion and oxygenation in a 31-year-old patient with poorly-controlled asthma. Acidosis promptly reversed on discontinuation of inhaled beta-agonists. Conclusion Lactic acidosis secondary to inhaled beta-agonist administration may be a common scenario which can be misinterpreted very easily and can confuse the clinical picture. Further studies will be needed to establish the exact aetiology of this lactic acid production.

Lactic acid and lactates

NARCIS (Netherlands)

Schreurs, V.V.A.M.

2010-01-01

This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a

DEVELOPMENT OF VEGETABLE PUREES AND DRINKS BY LACTIC ACID FERMENTATION

Directory of Open Access Journals (Sweden)

At. Kraevska

2014-03-01

Full Text Available The object of this work was to investigate the possibility for development of vegetable purees and drinks by lactic acid fermentation. It was found that by the direct lactic acid fermentation of Lb.plantarum strain 226/1 the vitamin composition of vegetable purees is preserved and the biological value is increased. Drinks, prepared from fermented vegetable purees were remarkable with the pleasant lactic acid taste, the sucrose-acid composition was stable and balanced and they can be used both in the rational and in the dietary nutrition.

Lignin poly(lactic acid) copolymers

Energy Technology Data Exchange (ETDEWEB)

Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

2017-02-14

Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

Purification of bacteriocins produced by lactic acid bacteria.

Science.gov (United States)

Saavedra, Lucila; Castellano, Patricia; Sesma, Fernando

2004-01-01

Bacteriocins are antibacterial substances of a proteinaceous nature that are produced by different bacterial species. Lactic acid bacteria (LAB) produce biologically active peptides or protein complexes that display a bactericidal mode of action almost exclusively toward Gram-positive bacteria and particularly toward closely related species. Generally they are active against food spoilage and foodborne pathogenic microorganisms including Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, and Listeria monocytogenes. There is an increased tendency to use natural occurring metabolites to prevent the growth of undesirable flora in foodstuffs. These metabolites could replace the use of chemical additives such as sorbic acid, sulfur dioxide, nitrite, nitrate, and others. For instance, bacteriocins produced by LAB may be promising for use as bio-preservaties. Bacteriocins of lactic acid bacteria are typically cationic, hydrophobic peptides and differ widely in many characteristics including molecular weight, presence of particular groups of amino acids, pI, net positive charge, and post-translational modifications of certain amino acids. This heterogeneity within the LAB bacteriocins may explain the different procedures for isolation and purification developed so far. The methods most frequently used for isolation, concentration, and purification involve salt precipitation of bacteriocins from culture supernatants, followed by various combinations of gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). In this chapter, a protocol is described that combines several methods used in our laboratory for the purification of two cationic bacteriocins, Lactocin 705AL and Enterocin CRL10, produced by Lactobacillus casei CRL705 and Enterococcus mundtii CRL10, respectively.

Production of lactic acid from C6-polyols by alkaline hydrothermal reactions

International Nuclear Information System (INIS)

Zhou Huazhen; Jin Fangming; Wu Bing; Cao Jianglin; Duan Xiaokun; Kishita, Atsushi

2010-01-01

Production of lactic acid from C6-polyols (Mannitol) under alkaline hydrothermal conditions was investigated. Experiments were performed to examine the difference in the production of lactic acid between C6-polyols and C3-polyols (glycerine), as well as C6-aldoses (glucose). Results showed that the yield of lactic acid from C6-polyols was lower than that from both glycerine and glucose. It indicated that long chain polyols might follow a different reaction pathway from that of glycerine. Further investigation is needed to clarify the reaction mechanism and improve the relatively low lactic acid acid yield from C6-polyols.

The behavior and importance of lactic acid complexation in Talspeak extraction systems

International Nuclear Information System (INIS)

Grimes, Travis S.; Nilsson, Mikael; Nash, Kenneth L.

2008-01-01

Advanced partitioning of spent nuclear fuel in the UREX +la process relies on the TALSPEAK process for separation of fission-product lanthanides from trivalent actinides. The classic TALSPEAK utilizes an aqueous medium of both lactic acid and diethylenetriaminepentaacetic acid and the extraction reagent di(2-ethylhexyl)phosphoric acid in an aromatic diluent. In this study, the specific role of lactic acid and the complexes involved in the extraction of the trivalent actinides and lanthanides have been investigated using 14 C-labeled lactic acid. Our results show that lactic acid partitions between the phases in a complex fashion. (authors)

Longitudinal acoustic properties of poly(lactic acid) and poly(lactic-co-glycolic acid)

International Nuclear Information System (INIS)

Parker, N G; Povey, M J W; Mather, M L; Morgan, S P

2010-01-01

Acoustics offers rich possibilities for characterizing and monitoring the biopolymer structures being employed in the field of biomedical engineering. Here we explore the rudimentary acoustic properties of two common biodegradable polymers: poly(lactic acid) and poly(lactic-co-glycolic acid). A pulse-echo technique is developed to reveal the bulk speed of sound, acoustic impedance and acoustic attenuation of small samples of the polymer across a pertinent temperature range of 0-70 0 C. The glass transition appears markedly as both a discontinuity in the first derivative of the speed of sound and a sharp increase in the acoustic attenuation. We further extend our analysis to consider the role of ethanol, whose presence is observed to dramatically modify the acoustic properties and reduce the glass transition temperature of the polymers. Our results highlight the sensitivity of acoustic properties to a range of bulk properties, including visco-elasticity, molecular weight, co-polymer ratio, crystallinity and the presence of plasticizers.

Oriented gold ripple-like structures on poly-L-lactic acid

Energy Technology Data Exchange (ETDEWEB)

Juřík, Petr, E-mail: petr.jurik@gmail.com [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Slepička, Petr [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic); Mistrík, Jan; Janíček, Petr [Department of Applied Physics and Mathematics, University of Pardubice (Czech Republic); Rimpelová, Silvie [Department of Biochemistry and Microbiology, Institute of Chemical Technology, Prague (Czech Republic); Kolská, Zdeňka [Faculty of Science, University of J. E. Purkyně, Ústí nad Labem (Czech Republic); Švorčík, Václav [Department of Solid State Engineering, Institute of Chemical Technology, Prague (Czech Republic)

2014-12-01

Highlights: • We prepared oriented ripple-like structures on polymer surface with thin gold layer. • These structures show preferential orientation over large areas which is unusual for heat induced wrinkling. • Significant electrical and optical anisotropy was observed. • Zeta-potential, XPS, goniometry and ellipsometry suggest formation of gold lines separated by polymer gaps. • Increase in cell growth in comparison with poly-styrene mock was observed. - Abstract: In this paper chemical, morphological, electrical and biological properties of poly-L-lactic acid thin films with gold nanolayers were studied. These samples were examined as-sputtered and annealed at glass transition temperature. Morphological changes of poly-L-lactic films introduced by annealing were studied by means of atomic force microscopy. This method showed formation of oriented ripple-like structures on the surface of the film. X-ray photoelectron spectroscopy, goniometry, ellipsometry, sheet resistance measurement and electrokinetic analysis were used to determine distribution of gold on the surface. Combined data suggests that these ripple-like structures were formed by gold lines with insulating polymer gaps in between. These lines show preferential orientation over large areas and under proper conditions offer simple way to form electrically anisotropic material on large scale. Also cytocompatibility was studied showing increased cell adhesion and proliferation of mouse embryonic fibroblasts offering another use for these easily formed structures.

Oriented gold ripple-like structures on poly-L-lactic acid

International Nuclear Information System (INIS)

Juřík, Petr; Slepička, Petr; Mistrík, Jan; Janíček, Petr; Rimpelová, Silvie; Kolská, Zdeňka; Švorčík, Václav

2014-01-01

Highlights: • We prepared oriented ripple-like structures on polymer surface with thin gold layer. • These structures show preferential orientation over large areas which is unusual for heat induced wrinkling. • Significant electrical and optical anisotropy was observed. • Zeta-potential, XPS, goniometry and ellipsometry suggest formation of gold lines separated by polymer gaps. • Increase in cell growth in comparison with poly-styrene mock was observed. - Abstract: In this paper chemical, morphological, electrical and biological properties of poly-L-lactic acid thin films with gold nanolayers were studied. These samples were examined as-sputtered and annealed at glass transition temperature. Morphological changes of poly-L-lactic films introduced by annealing were studied by means of atomic force microscopy. This method showed formation of oriented ripple-like structures on the surface of the film. X-ray photoelectron spectroscopy, goniometry, ellipsometry, sheet resistance measurement and electrokinetic analysis were used to determine distribution of gold on the surface. Combined data suggests that these ripple-like structures were formed by gold lines with insulating polymer gaps in between. These lines show preferential orientation over large areas and under proper conditions offer simple way to form electrically anisotropic material on large scale. Also cytocompatibility was studied showing increased cell adhesion and proliferation of mouse embryonic fibroblasts offering another use for these easily formed structures

Monascus ruber as cell factory for lactic acid production at low pH.

Science.gov (United States)

Weusthuis, Ruud A; Mars, Astrid E; Springer, Jan; Wolbert, Emil Jh; van der Wal, Hetty; de Vrije, Truus G; Levisson, Mark; Leprince, Audrey; Houweling-Tan, G Bwee; Pha Moers, Antoine; Hendriks, Sjon Na; Mendes, Odette; Griekspoor, Yvonne; Werten, Marc Wt; Schaap, Peter J; van der Oost, John; Eggink, Gerrit

2017-07-01

A Monascus ruber strain was isolated that was able to grow on mineral medium at high sugar concentrations and 175g/l lactic acid at pH 2.8. Its genome and transcriptomes were sequenced and annotated. Genes encoding lactate dehydrogenase (LDH) were introduced to accomplish lactic acid production and two genes encoding pyruvate decarboxylase (PDC) were knocked out to subdue ethanol formation. The strain preferred lactic acid to glucose as carbon source, which hampered glucose consumption and therefore also lactic acid production. Lactic acid consumption was stopped by knocking out 4 cytochrome-dependent LDH (CLDH) genes, and evolutionary engineering was used to increase the glucose consumption rate. Application of this strain in a fed-batch fermentation resulted in a maximum lactic acid titer of 190g/l at pH 3.8 and 129g/l at pH 2.8, respectively 1.7 and 2.2 times higher than reported in literature before. Yield and productivity were on par with the best strains described in literature for lactic acid production at low pH. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Enhanced L-lactic acid production from biomass-derived xylose by a mutant Bacillus coagulans.

Science.gov (United States)

Zheng, Zhaojuan; Cai, Cong; Jiang, Ting; Zhao, Mingyue; Ouyang, Jia

2014-08-01

Xylose effective utilization is crucial for production of bulk chemicals from low-cost lignocellulosic substrates. In this study, an efficient L-lactate production process from xylose by a mutant Bacillus coagulans NL-CC-17 was demonstrated. The nutritional requirements for L-lactate production by B. coagulans NL-CC-17 were optimized statistically in shake flask fermentations. Corn steep liquor powder and yeast exact were identified as the most significant factors by the two-level Plackett-Burman design. Steepest ascent experiments were applied to approach the optimal region of the two factors, and a central composite design was employed to determine their optimal levels. The optimal medium was used to perform batch fermentation in a 3-l bioreactor. A maximum of 90.29 g l(-1)  L-lactic acid was obtained from 100 g l(-1) xylose in 120 h. When using corn stove prehydrolysates as substrates, 23.49 g l(-1)  L-lactic acid was obtained in 36 h and the yield was 83.09 %.

Lactic acid fermentation of dahlia tuber starch and waste using Lactobacillus bulgaricus: A comparative study

Science.gov (United States)

Praputri, E.; Sundari, E.; Martynis, M.; Agenta, P.

2018-03-01

Lactic acid fermentation of dahlia tuber starch and waste was performed by means of Lactobacillus bulgaricus through enzymatic hydrolysis followed by fermentation process. The effect of pH condition on lactic acid production was investigated during the process. The selected bacteria produced lactic acid after 24 hours of fermentation and the productivity was increase after 24 hours of fermentation. After 120 hours of fermentation, it was found that dahlia tuber starch can produce up to 16.18% of lactic acid, whereas lactic acid produced from dahlia tuber waste was only 0.40% at pH of 4. The lactic acid production increase significantly for pH 3.5 and 4 until 96 hours of fermentation, then slowed down. On the other hand, for pH 4.5 the lactic acid production increase until 48 hours of fermentation and then slowed down. The identification of fermentation product indicated that the lactic acid produced in this study was 16.20%, acidic, yellow and cloudy with pH 3.4 – 4.2. The density of lactic acid produced ranged between 1.21 to 1.25 gr/ml.

Carbon-13 kinetic isotope effects in the decarbonylation of lactic acid of natural isotopic composition in phosphoric acid medium

International Nuclear Information System (INIS)

Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.; Kasprzyk, G.; Gumolka, L.; Staedter, W.

1993-01-01

The 13 C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphoric acids (PA) and by 85% H 3 PO 4 has been studied in the temperature interval of 60-150 deg C. The values of the 13 C (1) isotope effects in the decarbonylation of lactic acid in 100% H 3 PO 4 , in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate between the values calculated assuming that the C (1)- OH bond is broken in the rate-controlling step of dehydration and those calculated for rupture of the carbon-carbon bond in the transition state. In the temperature interval of 90-130 deg C the experimental 13 C fractionation factors determined in concentrated PA approach quite closely the 13 C fractionation corresponding to C (2)- C (1) bond scission. The 13 C (1) kinetic isotope effects in the decarbonylation of LA in 85% orthophosphoric acid in the temperature range of 110-150 deg C coincide with the 13 C isotope effects calculated assuming that the frequency corresponding to the C (1) -OH vibration is lost in the transition state of decarbonylation. A change of the mechanism of decarbonylation of LA in going from concentrated PA medium to 85% H 3 PO 4 has been suggested. A possible secondary 18 O and a primary 18 O kinetic isotope effect in decarbonylation of lactic acid in phosphoric acids media have been discussed, too. (author) 21 refs.; 3 tabs

Optimization of lactic acid production from glucose using geobacillus stearothermophilus strain 15

Science.gov (United States)

Kunasundari, Balakrishnan; Naresh, Sandrasekaran; Safie, Mohammad Farhan Mohd

2017-09-01

This study investigated the conversion efficiency of glucose to lactic acid by Geobacillus stearothermophilus strain 15. Six parameters (temperature, pH, incubation time, agitation speed, carbon and nitrogen concentrations) were screened to identify the most significant factors in affecting lactic acid production using glucose. Three most significant factors (temperature, pH and incubation time) were further optimized in this experiment to determine the optimal production of lactic acid. Numerical optimization gave the point prediction of lactic acid concentration produced at 9.95 g/L with the desirability of 0.979 at 40°C, pH 8.5, 24 h, 100 rpm with 5% glucose and 3% yeast extract.

THE EFFECTS OF INOCULANT LACTIC ACID BACTERIA ON THE FERMENTATION AND AEROBIC STABILITY OF SUNFLOWER SILAGE

Directory of Open Access Journals (Sweden)

Fisun Koc

2009-12-01

Full Text Available This study was carried out to determine the effects of actic acid bacterial inoculant on the fermentation and aerobic stability of sunflower silages. Sunflower was harvested at the milk stage. Inoculant-1174 (Pioneer®,USA was used as homofermentative lactic acid bacterial inoculant. Inoculant was applied 6.00 log10 cfu/g silage levels. Silages with no additive served as controls. After treatment, the chopped sunflower was ensiled in the PVC type laboratory silos. Three silos for each group were sampled for chemical and microbiological analysis on days 2, 4, 7, 14, 21, 28 and 56 after ensiling. At the end of the ensiling period, all silages were subjected to an aerobic stability test for 14 days. Neither inoculant improved the fermentation parameters of sunflower silages. At the end of the ensiling period, inoculant increased lactic acid bacteria (LAB and decreased yeast and mould numbers of silages. Inoculant treatment did not affect aerobic stability of silages.

Enhanced L-(+)-lactic acid production by an adapted strain of Rhizopus oryzae using corncob hydrolysate

DEFF Research Database (Denmark)

Bai, Dongmei; Li, S.Z.; Liu, Z.L.

2008-01-01

-added production of a variety of bioproducts. Lactic acid can be used as a precursor for poly-lactic acid production. Although current industrial lactic acid is produced by lactic acid bacteria using enriched medium, production by Rhizopus oryzae is preferred due to its exclusive formation of the......-isomer and a simple nutrition requirement by the fungus. Production of-L-(+)-lactic acid by R. oryzae using xylose has been reported; however, its yield and conversion rate are poor compared with that of using glucose. In this study, we report an adapted R. oryzae strain HZS6 that significantly improved efficiency...... of substrate utilization and enhanced production of L-(+)-lactic acid from corncob hydrolysate. It increased L-(+)-lactic acid final concentration, yield, and volumetric productivity more than twofold compared with its parental strain. The optimized growth and fermentation conditions for Strain HZS6 were...

Heme and menaquinone induced electron transport in lactic acid bacteria

NARCIS (Netherlands)

Brooijmans, R.J.W.; Smit, B.; Santos, dos F.; Riel, van J.; Vos, de W.M.; Hugenholtz, J.

2009-01-01

ABSTRACT: BACKGROUND: For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait.

Lactic Acid Bacteria : embarking on 30 more years of research

NARCIS (Netherlands)

Kok, Jan; Johansen, Eric; Kleerebezem, Michiel; Teusink, Bas

2014-01-01

The 11th International Symposium on Lactic Acid Bacteria Lactic Acid Bacteria play important roles in the pro- duction of food and feed and are increasingly used as health-promoting probiotics. The incessant scientific interest in these microorganisms by academic research groups as well as by

40 CFR 180.1090 - Lactic acid; exemption from the requirement of a tolerance.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Lactic acid; exemption from the... Exemptions From Tolerances § 180.1090 Lactic acid; exemption from the requirement of a tolerance. Lactic acid (2-hydroxypropanoic acid) is exempted from the requirement of a tolerance when used as a plant growth...

Poly(ethylene glycol) (PEG)-lactic acid nanocarrier-based degradable hydrogels for restoring the vaginal microenvironment

Science.gov (United States)

Rajan, Sujata Sundara; Turovskiy, Yevgeniy; Singh, Yashveer; Chikindas, Michael L.; Sinko, Patrick J.

2014-01-01

Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH 7.4) and acetate buffer (AB, pH 4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%–14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV. PMID:25223229

M2-like macrophage polarization in high lactic acid-producing head and neck cancer.

Science.gov (United States)

Ohashi, Toshimitsu; Aoki, Mitsuhiro; Tomita, Hiroyuki; Akazawa, Takashi; Sato, Katsuya; Kuze, Bunya; Mizuta, Keisuke; Hara, Akira; Nagaoka, Hitoshi; Inoue, Norimitsu; Ito, Yatsuji

2017-06-01

Reprogramming of glucose metabolism in tumor cells is referred to as the Warburg effect and results in increased lactic acid secretion into the tumor microenvironment. We have previously shown that lactic acid has important roles as a pro-inflammatory and immunosuppressive mediator and promotes tumor progression. In this study, we examined the relationship between the lactic acid concentration and expression of LDHA and GLUT1, which are related to the Warburg effect, in human head and neck squamous cell carcinoma (HNSCC). Tumors expressing lower levels of LDHA and GLUT1 had a higher concentration of lactic acid than those with higher LDHA and GLUT1 expression. Lactic acid also suppressed the expression of LDHA and GLUT1 in vitro. We previously reported that lactic acid enhances expression of an M2 macrophage marker, ARG1, in murine macrophages. Therefore, we investigated the relationship between the lactic acid concentration and polarization of M2 macrophages in HNSCC by measuring the expression of M2 macrophage markers, CSF1R and CD163, normalized using a pan-macrophage marker, CD68. Tumors with lower levels of CD68 showed a higher concentration of lactic acid, whereas those with higher levels of CSF1R showed a significantly higher concentration of lactic acid. A similar tendency was observed for CD163. These results suggest that tumor-secreted lactic acid is linked to the reduction of macrophages in tumors and promotes induction of M2-like macrophage polarization in human HNSCC. © 2017 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Chemical and sensory characteristics of frozen wheygurt with the addition of taro and lesser yam flours as thickening agent

Science.gov (United States)

Nurhartadi, E.; Utami, R.; Widowati, E.; Karunawati, B. M.

2018-01-01

Cheese whey is a waste product from cheese processing. It has low solid contents thus required the addition of a thickening agent. Lactic acid bacteria could utilize it in the fermented drink. This research aims to study the effect of taro and lesser yam flour addition as a thickening agent on chemical and sensory characteristics of frozen wheygurt. This research used Complete Randomized Design (CRD) with one factor that is variation ratio of taro and lesser yam flour F1 (4: 0), F2 (3: 1), F3 (2: 2), F4 (1: 3), F5 (0: 4). The number of lactic acid bacteria cell determined by using hemocytometer. The lactic acid content determined by the titrimetric method by using 0.1 N NaOH and phenolphthalein as indicator. pH value measured with pH meter. Sensory characteristics evaluated using hedonic test. The result showed that the addition of taro and lesser yam flour have a significant effect on the number of lactic acid bacteria in frozen wheygurt. The higher lesser yam flour addition, the higher lactic acid bacteria count on frozen wheygurt, due to lesser yam higher glucose and fructo-oligosaccharide content than taro. The higher lesser yam addition, the higher the lactic acid produced. The higher the total bacteria and higher levels of lactic acid, the lower the pH obtained. The conclusion of this study is addition ratio of taro and lesser yam flour effect on the chemical characteristics of frozen wheygurt. There is no difference in the level of acceptance of the panelists in sensory evaluation.

Co-electrospun gelatin-poly(L-lactic acid) scaffolds: Modulation of mechanical properties and chondrocyte response as a function of composition

Energy Technology Data Exchange (ETDEWEB)

Torricelli, Paola [Preclinical and Surgical Studies Laboratory, Codivilla Putti Research Institute, Rizzoli Orthopaedic Institute, via di Barbiano, 1/10, 40136 Bologna (Italy); Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies—Department Rizzoli Research, Innovation, Technology, via di Barbiano, 1/10, 40136 Bologna (Italy); Gioffrè, Michela; Fiorani, Andrea; Panzavolta, Silvia [Department of Chemistry “G. Ciamician” and National Consortium of Materials Science and Technology (INSTM, Bologna RU), University of Bologna (Italy); Gualandi, Chiara [Department of Chemistry “G. Ciamician” and National Consortium of Materials Science and Technology (INSTM, Bologna RU), University of Bologna (Italy); Advanced Mechanics and Materials—Interdepartmental Center for Industrial Research (AMM ICIR), University of Bologna (Italy); Fini, Milena [Preclinical and Surgical Studies Laboratory, Codivilla Putti Research Institute, Rizzoli Orthopaedic Institute, via di Barbiano, 1/10, 40136 Bologna (Italy); Laboratory of Biocompatibility, Innovative Technologies and Advanced Therapies—Department Rizzoli Research, Innovation, Technology, via di Barbiano, 1/10, 40136 Bologna (Italy); Focarete, Maria Letizia, E-mail: marialetizia.focarete@unibo.it [Department of Chemistry “G. Ciamician” and National Consortium of Materials Science and Technology (INSTM, Bologna RU), University of Bologna (Italy); Health Sciences and Technologies—Interdepartmental Center for Industrial Research (HST-ICIR) (Italy); Bigi, Adriana [Department of Chemistry “G. Ciamician” and National Consortium of Materials Science and Technology (INSTM, Bologna RU), University of Bologna (Italy)

2014-03-01

Bio-synthetic scaffolds of interspersed poly(L-lactic acid) (PLLA) and gelatin (GEL) fibers are fabricated by co-electrospinning. Tailored PLLA/GEL compositions are obtained and GEL crosslinking with genipin provides for the maintenance of good fiber morphology. Scaffold tensile mechanical properties are intermediate between those of pure PLLA and GEL and vary as a function of PLLA content. Primary human chondrocytes grown on the scaffolds exhibit good proliferation and increased values of the differentiation parameters, especially for intermediate PLLA/GEL compositions. Mineralization tests enable the deposition of a uniform layer of poorly crystalline apatite onto the scaffolds, suggesting potential applications involving cartilage as well as cartilage–bone interface tissue engineering. - Highlights: • Bio-synthetic scaffolds of PLLA and gelatin are produced by co-electrospinning. • Scaffolds with tailored PLLA–gelatin composition are fabricated. • PLLA/gelatin ratio controls scaffold mechanical properties and mineralization. • Chondrocyte proliferation and differentiation are modulated. • Scaffolds are suitable for cartilage–bone interface tissue engineering.

The production of lactic acid on liquid distillery stillage by Lactobacillus rhamnosus ATCC 7469

OpenAIRE

Đukić-Vuković, Aleksandra; Mojović, Ljiljana; Pejin, Dušanka; Vukašinović-Sekulić, Maja; Rakin, Marica; Nikolić, Svetlana; Pejin, Jelena

2011-01-01

The production of lactic acid on a liquid distillery stillage remaining after the bioethanol production on a mixture of waste bread and waste water from the production of wheat gluten was studied in this work. The lactic acid fermentation was performed with a probiotic lactic acid bacteria Lactobacillus rhamnosus ATCC 7469. During the fermentation, parameters such as the concentration of lactic acid (according to Taylor method), the concentration of reducing sugars (spectrophotometric method ...

Lactic acid levels in pleural fluid from patients with bacterial pleuritis.

OpenAIRE

Riley, T V

1985-01-01

Pleural fluid lactic acid estimations were carried out on 60 samples by gas-liquid chromatography. Lactic acid levels in 12 patients with bacterial pleural infection were statistically significantly higher (mean, 287 mg/dl; range, 135 to 482 mg/dl) than in 18 patients with malignancy (mean, 71 mg/dl; range, 24 to 157 mg/dl) and 30 other patients with pleural effusions (mean, 19 mg/dl; range, 10 to 57 mg/dl). The determination of pleural fluid lactic acid may help in differentiating between em...

L-lactic acid production by Aspergillus brasiliensis overexpressing the heterologous ldha gene from Rhizopus oryzae.

Science.gov (United States)

Liaud, Nadège; Rosso, Marie-Noëlle; Fabre, Nicolas; Crapart, Sylvaine; Herpoël-Gimbert, Isabelle; Sigoillot, Jean-Claude; Raouche, Sana; Levasseur, Anthony

2015-05-03

Lactic acid is the building block of poly-lactic acid (PLA), a biopolymer that could be set to replace petroleum-based plastics. To make lactic acid production cost-effective, the production process should be carried out at low pH, in low-nutrient media, and with a low-cost carbon source. Yeasts have been engineered to produce high levels of lactic acid at low pH from glucose but not from carbohydrate polymers (e.g. cellulose, hemicellulose, starch). Aspergilli are versatile microbial cell factories able to naturally produce large amounts of organic acids at low pH and to metabolize cheap abundant carbon sources such as plant biomass. However, they have never been used for lactic acid production. To investigate the feasibility of lactic acid production with Aspergillus, the NAD-dependent lactate dehydrogenase (LDH) responsible for lactic acid production by Rhizopus oryzae was produced in Aspergillus brasiliensis BRFM103. Among transformants, the best lactic acid producer, A. brasiliensis BRFM1877, integrated 6 ldhA gene copies, and intracellular LDH activity was 9.2 × 10(-2) U/mg. At a final pH of 1.6, lactic acid titer reached 13.1 g/L (conversion yield: 26%, w/w) at 138 h in glucose-ammonium medium. This extreme pH drop was subsequently prevented by switching nitrogen source from ammonium sulfate to Na-nitrate, leading to a final pH of 3 and a lactic acid titer of 17.7 g/L (conversion yield: 47%, w/w) at 90 h of culture. Final titer was further improved to 32.2 g/L of lactic acid (conversion yield: 44%, w/w) by adding 20 g/L glucose to the culture medium at 96 h. This strain was ultimately able to produce lactic acid from xylose, arabinose, starch and xylan. We obtained the first Aspergillus strains able to produce large amounts of lactic acid by inserting recombinant ldhA genes from R. oryzae into a wild-type A. brasiliensis strain. pH regulation failed to significantly increase lactic acid production, but switching nitrogen source and changing culture feed

Transcriptional Response to Lactic Acid Stress in the Hybrid Yeast Zygosaccharomyces parabailii.

Science.gov (United States)

Ortiz-Merino, Raúl A; Kuanyshev, Nurzhan; Byrne, Kevin P; Varela, Javier A; Morrissey, John P; Porro, Danilo; Wolfe, Kenneth H; Branduardi, Paola

2018-03-01

Lactic acid has a wide range of applications starting from its undissociated form, and its production using cell factories requires stress-tolerant microbial hosts. The interspecies hybrid yeast Zygosaccharomyces parabailii has great potential to be exploited as a novel host for lactic acid production, due to high organic acid tolerance at low pH and a fermentative metabolism with a high growth rate. Here we used mRNA sequencing (RNA-seq) to analyze Z. parabailii 's transcriptional response to lactic acid added exogenously, and we explore the biological mechanisms involved in tolerance. Z. parabailii contains two homeologous copies of most genes. Under lactic acid stress, the two genes in each homeolog pair tend to diverge in expression to a significantly greater extent than under control conditions, indicating that stress tolerance is facilitated by interactions between the two gene sets in the hybrid. Lactic acid induces downregulation of genes related to cell wall and plasma membrane functions, possibly altering the rate of diffusion of lactic acid into cells. Genes related to iron transport and redox processes were upregulated, suggesting an important role for respiratory functions and oxidative stress defense. We found differences in the expression profiles of genes putatively regulated by Haa1 and Aft1/Aft2, previously described as lactic acid responsive in Saccharomyces cerevisiae Furthermore, formate dehydrogenase ( FDH ) genes form a lactic acid-responsive gene family that has been specifically amplified in Z. parabailii in comparison to other closely related species. Our study provides a useful starting point for the engineering of Z. parabailii as a host for lactic acid production. IMPORTANCE Hybrid yeasts are important in biotechnology because of their tolerance to harsh industrial conditions. The molecular mechanisms of tolerance can be studied by analyzing differential gene expression under conditions of interest and relating gene expression patterns

Antagonism Between Osmophilic Lactic Acid Bacteria and Yeasts in Brine Fermentation of Soy Sauce

OpenAIRE

Noda, Fumio; Hayashi, Kazuya; Mizunuma, Takeji

1980-01-01

Brine fermentation by osmophilic lactic acid bacteria and yeasts for long periods of time is essential to produce a good quality of shoyu (Japanese fermented soy sauce). It is well known that lactic acid fermentation by osmophilic lactic acid bacteria results in the depression of alcoholic fermentation by osmophilic yeasts, but the nature of the interaction between osmophilic lactic acid bacteria and yeasts in brine fermentation of shoyu has not been revealed. The inhibitory effect of osmophi...

Linezolid-induced lactic acidosis: the thin line between bacterial and mitochondrial ribosomes.

Science.gov (United States)

Santini, Alessandro; Ronchi, Dario; Garbellini, Manuela; Piga, Daniela; Protti, Alessandro

2017-07-01

Linezolid inhibits bacterial growth by targeting bacterial ribosomes and by interfering with bacterial protein synthesis. Lactic acidosis is a rare, but potentially lethal, side effect of linezolid. Areas covered: The pathogenesis of linezolid-induced lactic acidosis is reviewed with special emphasis on aspects relevant to the recognition, prevention and treatment of the syndrome. Expert opinion: Linezolid-induced lactic acidosis reflects the untoward interaction between the drug and mitochondrial ribosomes. The inhibition of mitochondrial protein synthesis diminishes the respiratory chain enzyme content and thus limits aerobic energy production. As a result, anaerobic glycolysis and lactate generation accelerate independently from tissue hypoxia. In the absence of any confirmatory test, linezolid-induced lactic acidosis should be suspected only after exclusion of other, more common, causes of lactic acidosis such as hypoxemia, anemia or low cardiac output. Normal-to-high whole-body oxygen delivery, high venous oxygen saturation and lack of response to interventions that effectively increase tissue oxygen provision all suggest a primary defect in oxygen use at the mitochondrial level. During prolonged therapy with linezolid, blood drug and lactate levels should be regularly monitored. The current standard-of-care treatment of linezolid-induced lactic acidosis consists of drug withdrawal to reverse mitochondrial intoxication and intercurrent life support.

Laboratory evaluation of lactic acid on attraction of Culex spp. (Diptera: Culicidae).

Science.gov (United States)

Allan, Sandra A; Bernier, Ulrich R; Kline, Daniel L

2010-12-01

The role of lactic acid was evaluated for attraction of Culex nigripalpus, Culex quinquefasciatus, Culex tarsalis, and Aedes aegypti in the laboratory using a dual-port olfactometer. When lactic acid was combined with chicken odor, attraction was increased for Cx. quinquefasciatus compared to chicken odor alone but not for Cx. nigripalpus, Cx. tarsalis, and Ae. aegypti. Lactic acid combined with hand odor did not change attraction of Cx. tarsalis and Ae. aegypti but decreased attraction of Cx. nigripalpus and Cx. quinquefasciatus. The addition of lactic acid to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. Use of commercial lactic acid baits with CO(2) resulted in a similar trend except for Cx. nigripalpus which showed no difference. A blend of lactic acid, acetone, and dimethyl disulfide was attractive to Ae. aegypti (63.4%) but elicited low responses by all Culex spp. (1.3-26.8%). Addition of the blend to CO(2) increased attraction of Ae. aegypti and Cx. quinquefasciatus but reduced attraction of Cx. nigripalpus and Cx. tarsalis. The mixture of compounds plus CO(2) was as attractive as a hand for Cx. quinquefasciatus, Cx. tarsalis, and Ae. aegypti. © 2010 The Society for Vector Ecology.

Unusual Case of Severe Lactic Acidosis in a Liver Transplant Patient

Directory of Open Access Journals (Sweden)

Shweta Yemul Golhar

2017-01-01

Full Text Available Lactic acidosis is a standard indicator for oxygen debt and some other very significant causes. We describe a case of liver transplant patient presenting with vague abdominal pain and lactic acidosis without any liver dysfunction/failure/ischemia/rejection or sepsis. The imaging studies showed vague bowel edema and normal hepatic perfusion. The patient continued to deteriorate with rising lactic acidosis when a repeat CT abdomen eventually showed signs of lymphomatosis peritonei. Biopsy revealed the unusual diagnosis of posttransplant lymphoproliferative disorder. Immediate discontinuation of immunosuppression and initiation of chemotherapy led to clinical improvement. Our intention of presenting this case is to increase awareness of posttransplant lymphoma and propose lactic acidosis as not only an indicator of liver dysfunction or rejection but also an aid for diagnosis of this unusual but fatal and potentially curable condition.

Separation and purification of lactic acid. Thermal catalytic depolymerization of poly-lactic acid into lactide; Hakkoho nyusan no bunri seisei ni kansuru kenkyu. Pori nyusan no rakuchido eno sesshokuteki netsukai jugo

Energy Technology Data Exchange (ETDEWEB)

Morita, M.; Hirama, Y.; Liew, M. [Hokkaido National Industrial Research Institute, Sapporo (Japan)

1996-05-10

A new separation and purification method for lactic acid from fermentation broth is proposed by which poly-lactic acid produced from unpurified lactic acid is catalytically depolymerized into lactide fractions then further purified into lactide. In the present study, thermal depolymerization catalysts were investigated for commercial use. Iron catalysts, especially metallic iron, and ferrous oxide and lactate, were found to provide almost the same catalytic activity and lactide composition in depolymerization products and those in tin octoate and antimony oxide catalysts. Ferrous oxide was also applied to depolymerize poly-lactic acid derived form unpurified lactic acid to compare catalytic activity and lactide composition and was confirmed to show results similar to those of pure polymer. Based on these findings, it is concluded that iron catalysts can be used commercially. Furthermore, catalytic depolymerization of poly-lactic acids with different molecular weights were studied. Polymers with Mw 5,000-10,000 were found to be better for production of lactide, based on the behavior of depolymerization and lactide content in the product. 5 refs., 9 figs., 1 tab.

Modeling Lactic Fermentation of Gowé Using Lactobacillus Starter Culture.

Science.gov (United States)

de J C Munanga, Bettencourt; Loiseau, Gérard; Grabulos, Joël; Mestres, Christian

2016-12-01

A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso's primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μ max values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum , respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis , with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter.

Chemical characteristic of salt fermented meat inoculated with Pediococcus ssp

Science.gov (United States)

Pramono, Y. B.; Rahayu, E. S.; Suparmo; Utami, T.; Nurwantoro; Yunianto, V. D.

2018-01-01

The research goal is knowing of the characteristict of salt fermented meat by Pediococcus ssp. There were microbiological, chemical, and off-flavor compound during fermentation. This study was conducted on research of influence of salt-meat fermentation inoculated used starter. They were included microbiological characteristics, and chemical characteristics. Microbiological characteristics observed were total bacteria, number of coliform groups, bacteria producing bioamine, and total lactic acid bacteria. The result showed that decreasing of coliform and bioamine producer bacteria, and total lactic acid bacteria decreased 3 log cycle. While the soluble protein increased of 7-8% and bioamine increased of 5-6 mg/100 g. And then Off-flavour compound, TVN and TMA increased of 36-20 mg/100g and 16-30 mg/100g, respectively. Conclusion of the research that Pedioccoccus ssp. influenced salt fermented meat.

Improvement of lactic acid production in Saccharomyces cerevisiae by a deletion of ssb1.

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Lee, Jinsuk J; Crook, Nathan; Sun, Jie; Alper, Hal S

2016-01-01

Polylactic acid (PLA) is an important renewable polymer, but current processes for producing its precursor, lactic acid, suffer from process inefficiencies related to the use of bacterial hosts. Therefore, improving the capacity of Saccharomyces cerevisiae to produce lactic acid is a promising approach to improve industrial production of lactic acid. As one such improvement required, the lactic acid tolerance of yeast must be significantly increased. To enable improved tolerance, we employed an RNAi-mediated genome-wide expression knockdown approach as a means to rapidly identify potential genetic targets. In this approach, several gene knockdown targets were identified which confer increased acid tolerance to S. cerevisiae BY4741, of which knockdown of the ribosome-associated chaperone SSB1 conferred the highest increase (52%). This target was then transferred into a lactic acid-overproducing strain of S. cerevisiae CEN.PK in the form of a knockout and the resulting strain demonstrated up to 33% increased cell growth, 58% increased glucose consumption, and 60% increased L-lactic acid production. As SSB1 contains a close functional homolog SSB2 in yeast, this result was counterintuitive and may point to as-yet-undefined functional differences between SSB1 and SSB2 related to lactic acid production. The final strain produced over 50 g/L of lactic acid in under 60 h of fermentation.

Cocrystallization as a tool to solve deliquescence issues: The case of L-lactic acid

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de Maere d'Aertrycke, J. B.; Robeyns, K.; Willocq, J.; Leyssens, T.

2017-08-01

L-Lactic acid is an organic acid used in various fields such as food, cosmetic or pharmaceutical industry. It furthermore is the building-block of poly-lactic acid, a biodegradable and bioavailable polymer. Still, handling L-lactic acid under its solid form remains less straightforward mainly due to its deliquescent behavior, a phase transition from the solid to the dissolved state resulting from air humidity absorption. If several techniques are already known to avoid or reduce deliquescence, the use of cocrystallization in this context is still poorly investigated. In this paper, we investigate whether cocrystallization can be used as a suitable solution for deliquescence in the case of L-lactic acid. Out of 32 possible coformers tested, four were found to form cocrystals with L-lactic acid and the crystal structures of 1:1 L-lactic acid:D-tryptophan and 1:1 L-lactic acid:3-nitrobenzamide were determined. The hygroscopic behavior of these latter two was studied and compared to the behavior of pure L-lactic acid. Significant improvement was observed: dynamic vapor sorption at 25 °C revealed that water absorbed at 90% relative humidity dropped from 1.3157 g/gsample to 0.0017 g/gsample or 0.0299 g/gsample, with cocrystals of D-tryptophan and 3-nitrobenzamide respectively. This illustrates the effectiveness of cocrystallization as a tool to treat deliquescent materials.

Nucleotide Metabolism and its Control in Lactic Acid Bacteria

DEFF Research Database (Denmark)

Kilstrup, Mogens; Hammer, Karin; Jensen, Peter Ruhdal

2005-01-01

Most metabolic reactions are connected through either their utilization of nucleotides or their utilization of nucleotides or their regulation by these metabolites. In this review the biosynthetic pathways for pyrimidine and purine metabolism in lactic acid bacteria are described including...... the interconversion pathways, the formation of deoxyribonucleotides and the salvage pathways for use of exogenous precursors. The data for the enzymatic and the genetic regulation of these pathways are reviewed, as well as the gene organizations in different lactic acid bacteria. Mutant phenotypes and methods...... for manipulation of nucleotide pools are also discussed. Our aim is to provide an overview of the physiology and genetics of nucleotide metabolism and its regulation that will facilitate the interpretation of data arising from genetics, metabolomics, proteomics, and transcriptomics in lactic acid bacteria....

Characterization of lactic acid bacteria isolated from poultry farms in ...

African Journals Online (AJOL)

The Lactobacilli strains, both isolated from faeces, produced higher amounts of cells and lactic acid from soils as compared to the lactococci strain isolated from feathers. L (+)-lactic acid is the only optical isomer for use in pharmaceutical and food industries because is only adapted to assimilate this form. The optical isomers ...

Ibuprofen-loaded poly(lactic-co-glycolic acid films for controlled drug release

Directory of Open Access Journals (Sweden)

Pang JM

2011-04-01

Full Text Available Jianmei Pang1, Yuxia Luan1, Feifei Li1, Xiaoqing Cai1, Jimin Du2, Zhonghao Li31School of Pharmaceutical Science, Shandong University, Jinan, Shandong Province, PR China; 2School of Chemistry and Chemical Engineering, Anyang Normal University, Henan Province, PR China; 3School of Materials Science and Engineering, Shandong University, Jinan, Shandong Province, PR ChinaAbstract: Ibuprofen- (IBU loaded biocompatible poly(lactic-co-glycolic acid (PLGA films were prepared by spreading polymer/ibuprofen solution on the nonsolvent surface. By controlling the weight ratio of drug and polymer, different drug loading polymer films can be obtained. The synthesized ibuprofen-loaded PLGA films were characterized with scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry. The drug release behavior of the as-prepared IBU-loaded PLGA films was studied to reveal their potential application in drug delivery systems. The results show the feasibility of the as-obtained films for controlling drug release. Furthermore, the drug release rate of the film could be controlled by the drug loading content and the release medium. The development of a biodegradable ibuprofen system, based on films, should be of great interest in drug delivery systems.Keywords: ibuprofen, controlled release, poly(lactic-co-glycolic acid, films

SOLID AND LIQUID PINEAPPLE WASTE UTILIZATION FOR LACTIC ACID FERMENTATION USING Lactobacillus delbrueckii

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Abdullah Abdullah

2012-01-01

Full Text Available The liquid and solid  pineapple wastes contain mainly sucrose, glucose, fructose and other nutrients. It therefore can potentially be used as carbon source for fermentation to produce organic acid. Recently, lactic acid has been considered to be an important raw material for production of biodegradable lactate polymer. The experiments were  carried out in batch fermentation using  the  liquid and solid pineapple wastes to produce lactic acid. The anaerobic fermentation of lactic acid were performed at 40 oC, pH 6, 5% inocolum and  50 rpm. Initially  results show that the liquid pineapple waste by  using Lactobacillus delbrueckii can be used as carbon source  for lactic acid fermentation. The production of lactic acid  are found to be 79 % yield, while only  56% yield was produced by using solid waste. 

Lactic Acid Bacteria as a new platform for sustainable production of fuels and chemicals

DEFF Research Database (Denmark)

Boguta, Anna Monika

generation biorefineries, the conversion of lignocellulose is a more complex process; thus, the pursue for a suitable microbe continues. In this PhD study, a wide collection of Lactic Acid Bacteria was systematically screened for the strains’ tolerance levels towards various inhibitors coming from...... experiments with increased concentrations of the key inhibitors, such as furfural and HMF, as well as with the presence of the most common combinations of inhibitors, mimicking real-life lignocellulosic feedstocks: sugarcane bagasse, wheat straw and soft wood. The two most promising strains were selected...... 20284 tolerance to furfural, an adaptation experiment was performed by continuous serial-transfer method. After 408 generations, an adapted strain A28 was isolated and showed an increased growth rate on the rich MRS medium with addition of furfural; yet, it also demonstrated a 27% better growth in MRS...

Highly efficient production of D-lactic acid from chicory-derived inulin by Lactobacillus bulgaricus.

Science.gov (United States)

Xu, Qianqian; Zang, Ying; Zhou, Jie; Liu, Peng; Li, Xin; Yong, Qiang; Ouyang, Jia

2016-11-01

Inulin is a readily available feedstock for cost-effective production of biochemicals. To date, several studies have explored the production of bioethanol, high-fructose syrup and fructooligosaccharide, but there are no studies regarding the production of D-lactic acid using inulin as a carbon source. In the present study, chicory-derived inulin was used for D-lactic acid biosynthesis by Lactobacillus bulgaricus CGMCC 1.6970. Compared with separate hydrolysis and fermentation processes, simultaneous saccharification and fermentation (SSF) has demonstrated the best performance of D-lactic acid production. Because it prevents fructose inhibition and promotes the complete hydrolysis of inulin, the highest D-lactic acid concentration (123.6 ± 0.9 g/L) with a yield of 97.9 % was obtained from 120 g/L inulin by SSF. Moreover, SSF by L. bulgaricus CGMCC 1.6970 offered another distinct advantage with respect to the higher optical purity of D-lactic acid (>99.9 %) and reduced number of residual sugars. The excellent performance of D-lactic acid production from inulin by SSF represents a high-yield method for D-lactic acid production from non-food grains.

Lactic acid production from xylose by engineered Saccharomyces cerevisiae without PDC or ADH deletion

Science.gov (United States)

Production of lactic acid from renewable sugars has received growing attention as lactic acid can be used for making renewable and bio-based plastics. However, most prior studies have focused on production of lactic acid from glucose despite cellulosic hydrolysates contain xylose as well as glucose....

Lactic Acid Yield Using Different Bacterial Strains, Its Purification, and Polymerization through Ring-Opening Reactions

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F. G. Orozco

2014-01-01

Full Text Available Laboratory-scale anaerobic fermentation was performed to obtain lactic acid from lactose, using five lactic acid bacteria: Lactococcus lactis, Lactobacillus bulgaricus, L. delbrueckii, L. plantarum, and L. delbrueckii lactis. A yield of 0.99 g lactic acid/g lactose was obtained with L. delbrueckii, from which a final concentration of 80.95 g/L aqueous solution was obtained through microfiltration, nanofiltration, and inverse osmosis membranes. The lactic acid was polymerized by means of ring-opening reactions (ROP to obtain poly-DL-lactic acid (PDLLA, with a viscosity average molecular weight (Mv of 19,264 g/mol.

Extreme lactic acidosis type B associated with metformin treatment

Science.gov (United States)

Vernersson, Einar; Frid, Anders; Sterner, Gunnar

2011-01-01

The elimination of metformin is exclusively through the kidneys and elevated plasma concentrations can cause lactic acidosis. We report a case of severe lactic acidosis (pH 6.60) occuring with ostensibly normal therapeutic doses of metformin in the setting of acute renal failure. Continuous veno-venous haemodiafiltration decreased plasma metformin concentrations from 266 lmol/L at presentation to 68 lmol/L, 21 h later. The patient improved rapidly. PMID:25984205

Efficient synthesis and physicochemical characterization of natural danshensu, its S isomer and intermediates thereof

Science.gov (United States)

Sidoryk, Katarzyna; Filip, Katarzyna; Cmoch, Piotr; Łaszcz, Marta; Cybulski, Marcin

2018-02-01

The synthesis and molecular structure details of R- 3,4-dihydroxyphenyl lactic acid (danshensu) and related compounds, i.e. S isomer and the key intermediates have been described. Danshensu is an important water soluble phenolic acid of Salvia miltiorrhiza herb (danshen or red sag) with numerous applications in traditional Chinese medicine (TCM). Our synthetic approach was based on the Knoevenagel condensation of the protected 3,4-dihydroxybenzaldehyd and Meldrum acid derivative, followed by asymmetric Sharples dihydroxylation, reductive mono dehydroxylation and final deprotection. All compounds were characterized by various spectroscopic techniques: 1H-, 13C- magnetic resonance (NMR); Fourier-transformed infrared (FTIR); Raman, HR mass spectroscopy. For the determination of compound optical purities original HPLC methods were developed which allowed for the efficient resolution of danshensu R and S enantiomers as well as its intermediate enantiomers, using commercially available chiral stationary phases. Furthermore, in order to better understand danshensu specificity as a potential API in drug formulation, the physicochemical properties of the compounds were studied by thermal analysis, including differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).

Lactic acid bacteria and the human gastrointestinal tract

DEFF Research Database (Denmark)

Hove, H; Nørgaard, H; Mortensen, P B

1999-01-01

OBJECTIVE: This review summarises the effects of lactic acid bacteria on lactose malabsorption, bacterial/viral or antibiotic associated diarrhoea, and describes the impact of lactic acid bacteria on cancer and the fermentative products in the colon. RESULTS: Eight studies (including 78 patients......) demonstrated that lactase deficient subjects absorbed lactose in yogurt better than lactose in milk, while two studies (25 patients) did not support this. Two studies (22 patients) showed that unfermented acidophilus milk was absorbed better than milk, while six studies (68 patients) found no significant...

Heme and menaquinone induced electron transport in lactic acid bacteria

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Santos Filipe

2009-05-01

Full Text Available Abstract Background For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Results Heme- (and menaquinone stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. Conclusion We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species.

Integrated production of lactic acid and biomass on distillery stillage.

Science.gov (United States)

Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Vukašinović-Sekulić, Maja S; Nikolić, Svetlana B; Pejin, Jelena D

2013-09-01

The possibilities of parallel lactic acid and biomass production in batch and fed-batch fermentation on distillery stillage from bioethanol production were studied. The highest lactic acid yield and productivity of 92.3 % and 1.49 g L(-1) h(-1) were achieved in batch fermentation with initial sugar concentration of 55 g L(-1). A significant improvement of the process was achieved in fed-batch fermentation where the concentration of lactic acid was increased to 47.6 % and volumetric productivity for 21 % over the batch process. A high number of Lactobacillus rhamnosus ATCC 7469 viable cells of 10(9) CFU ml(-1) was attained at the end of fed-batch fermentation. The survival of 92.9 % of L. rhamnosus cells after 3 h of incubation at pH 2.5 validated that the fermentation media remained after lactic acid removal could be used as a biomass-enriched animal feed thus making an additional value to the process.

Heme and menaquinone induced electron transport in lactic acid bacteria.

Science.gov (United States)

Brooijmans, Rob; Smit, Bart; Santos, Filipe; van Riel, Jan; de Vos, Willem M; Hugenholtz, Jeroen

2009-05-29

For some lactic acid bacteria higher biomass production as a result of aerobic respiration has been reported upon supplementation with heme and menaquinone. In this report, we have studied a large number of species among lactic acid bacteria for the existence of this trait. Heme- (and menaquinone) stimulated aerobic growth was observed for several species and genera of lactic acid bacteria. These include Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacilllus brevis, Lactobacillus paralimentarius, Streptococcus entericus and Lactococcus garviae. The increased biomass production without further acidification, which are respiration associated traits, are suitable for high-throughput screening as demonstrated by the screening of 8000 Lactococcus lactis insertion mutants. Respiration-negative insertion-mutants were found with noxA, bd-type cytochrome and menaquinol biosynthesis gene-disruptions. Phenotypic screening and in silico genome analysis suggest that respiration can be considered characteristic for certain species. We propose that the cyd-genes were present in the common ancestor of lactic acid bacteria, and that multiple gene-loss events best explains the observed distribution of these genes among the species.

THE SEARCH AND PROPERTIES OF LACTIC ACID BACTERIA PERSPECTIVE FOR BIOTECHNOLOGY

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Naumenko О. V.

2014-10-01

Full Text Available Search of biologically active Lactobacillus strains prospective for functional milk food production was the aim of the research. The study involved the lactic acid bacteria isolated from biological material of healthy humen and non- dairy lactic products. Using modern methodological approaches, the strains of lactic acid bacteria such as Lactobacillus casei 302, Lactobacillus acidophilus 35 and Streptococcus thermophilus 21 having high level of biological activity were selected. High biological potential of selected cultures of lactic acid bacteria, which could provide stability for the technological process of production and essential characteristics of bacterial preparations and fermented their products, was set. In vitro the experiments demonstrated that selected strains had valuable production properties, namely the ability to reduce level of cholesterol and lactose during development in milk, were resistant to virulent bacteriophages and aggressive compounds of the gastrointestinal tract, and high adhesive and antagonistic activities as well.

Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

Energy Technology Data Exchange (ETDEWEB)

Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour [Radiation Application Research School, Nuclear Science and Research Institute, North Kargar Ave., Tehran (Iran, Islamic Republic of)

2009-07-01

Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

International Nuclear Information System (INIS)

Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour

2009-01-01

Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

Ultrastructural observations of chemical peeling for skin rejuvenation (ultrastructural changes of the skin due to chemical peeling).

Science.gov (United States)

Omi, Tokuya; Sato, Shigeru; Numano, Kayoko; Kawana, Seiji

2010-02-01

Chemical peeling of the skin is commonly used as a means to treat photoaging, but the mechanism underlying its efficacy has not yet been fully clarified. We recently conducted chemical peeling of the skin with glycolic acid and lactic acid and observed it at the ultrastructural level. No changes in the horny layer or the upper epidermal layer were observed but there was dissociation and vacuolation between the basal cells and increases in vimentin filaments within fibroblasts and endothelial cells were seen. These findings suggest that chemical peeling of the skin with this type of agent directly induces collagen formation within the dermis and thus directly stimulates remodeling of the dermis.

Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

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Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

2015-11-01

The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs.

Modeling Lactic Fermentation of Gowé Using Lactobacillus Starter Culture

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Bettencourt de J. C. Munanga

2016-12-01

Full Text Available A global model of the lactic fermentation step of gowé was developed by assembling blocks hosting models for bacterial growth, lactic acid production, and the drop of pH during fermentation. Commercial strains of Lactobacillus brevis and of Lactobacillus plantarum were used; their growth was modeled using Rosso’s primary model and the gamma concept as a secondary model. The optimum values of pH and temperature were 8.3 ± 0.3, 44.6 ± 1.2 °C and 8.3 ± 0.3, 3.2 ± 37.1 °C with μmax values of 1.8 ± 0.2 and 1.4 ± 0.1 for L. brevis and L. plantarum respectively. The minimum inhibitory concentration of undissociated lactic acid was 23.7 mM and 35.6 mM for L. brevis and L. plantarum, respectively. The yield of lactic acid was five times higher for L. plantarum than for L. brevis, with a yield of glucose conversion to lactic acid close to 2.0 for the former and 0.8 for the latter. A model was developed to predict the pH drop during gowé fermentation. The global model was partially validated during manufacturing of gowé. The global model could be a tool to aid in the choice of suitable starters and to determine the conditions for the use of the starter.

Antifungal Poly(lactic acid) Films Containing Thymol and Carvone

OpenAIRE

Boonruang Kanchana; Chinsirikul Wannee; Hararak Bongkot; Kerddonfag Noppadon; Chonhenchob Vanee

2016-01-01

The goal of this study was to develop antifungal poly(lactic acid) films for food packaging applications. The antifungal compounds, thymol and R-(-)-carvone were incorporated into poly(lactic acid) (PLA)-based polymer at 10, 15 and 20% by weight. Film converting process consists of three steps including melt blending, sheet extrusion and biaxial stretching. The incorporation of antifungal compounds into the polymer matrix resulted in decreased Tg and Tm, increased gas permeabilility, reduced ...

From honeycomb- to microsphere-patterned surfaces of poly(lactic acid) and a starch-poly(lactic acid) blend via the breath figure method.

Science.gov (United States)

Duarte, Ana Rita C; Maniglio, Devid; Sousa, Nuno; Mano, João F; Reis, Rui L; Migliaresi, Claudio

2017-01-26

This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods. Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions - namely, polymer concentration, vapor atmosphere temperature and substrate - to evaluate the effect of these conditions on the morphology of the precipitates obtained. The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture. The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.

Metabolic engineering of lactic acid bacteria for the production of nutraceuticals

NARCIS (Netherlands)

Hugenholtz, J.; Sybesma, W.; Groot, M.N.; Wisselink, W.; Ladero, V.; Burgess, K.; Sinderen, van D.; Piard, J.C.; Eggink, G.; Smid, E.J.; Savoy, G.; Sesma, F.; Jansen, T.; Hols, P.; Kleerebezem, M.

2002-01-01

Lactic acid bacteria display a relatively simple and well-described metabolism where the sugar source is converted mainly to lactic acid. Here we will shortly describe metabolic engineering strategies on the level of sugar metabolism, that lead to either the efficient re-routing of the lactococcal

Batch fermentation of whey ultra filtrate by Lactobacillus helveticus for lactic acid production

Energy Technology Data Exchange (ETDEWEB)

Roy, D; Goulet, J; Le Duy, Q

1986-06-01

Cheese whey ultrafiltrate (WU) was used as the carbon source for the production of lactic acid by batch fermentation with Lactobacillus helveticus strain milano. The fermentation was conducted in a 400 ml fermentor at an agitation rate of 200 revolutions per minute and under conditions of controlled temperature (42 degrees C) and pH. In the whey ultrafiltrate-corn steep liquor (WU-CSL) medium, the optimal pH for fermentation was 5.9. Inoculum propagated in skim milk (SM) medium or in lactose synthetic (LS) medium resulted in the best performance in fermentation (in terms of growth, lactic acid production, lactic acid yield and maximum productivity of lactic acid), as compared to that propagated in glucose synthetic (GS) medium. The yeast extract ultrafiltrate (YEU) used as the nitrogen/growth factor source in the WU medium at 1.5% (w/v) gave the highest maximum productivity of lactic acid of 2.70 g/l-h, as compared to the CSL and the tryptone ultrafiltrate (TU). 27 references.

Efficient production of l-lactic acid by an engineered Thermoanaerobacterium aotearoense with broad substrate specificity

Science.gov (United States)

2013-01-01

Background Efficient conversion of lignocellulosic biomass to optically pure lactic acid is a key challenge for the economical production of biodegradable poly-lactic acid. A recently isolated strain, Thermoanaerobacterium aotearoense SCUT27, is promising as an efficient lactic acid production bacterium from biomass due to its broad substrate specificity. Additionally, its strictly anaerobic and thermophilic characteristics suppress contamination from other microoragnisms. Herein, we report the significant improvements of concentration and yield in lactic acid production from various lignocellulosic derived sugars, achieved by the carbon flux redirection through homologous recombination in T. aotearoense SCUT27. Results T. aotearoense SCUT27 was engineered to block the acetic acid formation pathway to improve the lactic acid production. The genetic manipulation resulted in 1.8 and 2.1 fold increase of the lactic acid yield using 10 g/L of glucose or 10 g/L of xylose as substrate, respectively. The maximum l-lactic acid yield of 0.93 g/g glucose with an optical purity of 99.3% was obtained by the engineered strain, designated as LA1002, from 50 g/L of substrate, which is very close to the theoretical value (1.0 g/g of glucose). In particular, LA1002 produced lactic acid at an unprecedented concentration up to 3.20 g/L using 10 g/L xylan as the single substrate without any pretreatment after 48 h fermentation. The non-sterilized fermentative production of l-lactic acid was also carried out, achieving values of 44.89 g/L and 0.89 g/g mixed sugar for lactic acid concentration and yield, respectively. Conclusions Blocking acetic acid formation pathway in T. aotearoense SCUT27 increased l-lactic acid production and yield dramatically. To our best knowledge, this is the best performance of fermentation on lactic acid production using xylan as the sole carbon source, considering the final concentration, yield and fermentation time. In addition, it should be

Statin precipitated lactic acidosis?

Science.gov (United States)

Neale, R; Reynolds, T M; Saweirs, W

2004-09-01

An 82 year old woman was admitted with worsening dyspnoea. Arterial blood gases were taken on air and revealed a pH of 7.39, with a partial pressure of CO2 (pCO2) of 1.2 kPa, pO2 of 19.3 kPa, HCO3 of 13.8 mmol/litre, and base excess of -16.3 mmol/litre: a compensated metabolic acidosis with hyperventilation induced hypocapnia, which is known to be a feature of lactic acidosis. There was also an increased anion gap ((Na140 + K4.0) - (Cl 106 + HCO3 13.8) = 24.2 mEq/litre (reference range, 7-16)), consistent with unmeasured cation. Lactate was measured and found to be raised at 3.33 mmol/litre (reference range, 0.9-1.7). After exclusion of common causes of lactic acidosis Atorvastatin was stopped and her acid-base balance returned to normal. Subsequently, thiamine was also shown to be deficient. The acidosis was thought to have been the result of a mitochondrial defect caused by a deficiency of two cofactors, namely: ubiquinone (as a result of inhibition by statin) and thiamine (as a result of dietary deficiency).

Enhancement of L(+)-Lactic Acid Production of Immobilized Rhizopus Oryzae Implanted by Ion Beams

International Nuclear Information System (INIS)

Fan Yonghong; Yang Yingge; Zheng Zhiming; Li Wen; Wang Peng; Yao Liming; Yu Zengliang

2008-01-01

Immobilized Rhizopus oryzae culturing may be a solution to the inhibited production of L(+)-lactic acid in submerged fermentation, which is caused by aggregated mycelia floc. In the present study, a R. oryzae mutant (RL6041) with a 90% conversion rate of glucose into L-lactic acid was obtained by N + implantation under the optimized conditions of a beam energy of 15 keV and a dose of 2.6 x 10 15 ions/cm 2 . Using polyurethane foam as the immobilization matrix, the optimal L-lactic acid production conditions were determined as 4 mm polyurethane foam, 150 r/min, 50 g/L ∼ 80 g/L of initial glucose, 38 deg. C and pH 6.0. 15-cycle repeated productions of L-lactic acid by immobilized RL6041 were performed under the optimized culturing conditions and over 80% of the glucose was converted into L-lactic acid in 30 hours on average. The results show that immobilized RL6041 is a promising candidate for continuous L-lactic acid production.

Breeding L(+)-lactic acid high productive mutant from xylose by nitrogen ions

International Nuclear Information System (INIS)

Yang Yingge; Li Wen; Liu Dan; Fan Yonghong; Wang Dongmei; Zheng Zhiming; Yu Zengliang

2007-01-01

In order to obtain higher L(+)-lactic acid yield strain fermentating from xylose, the original strain Rhizopus oryzae RLC41-6 was mutated by 10keV N + ion implantation. A mutant strain RQ4012 was obtained. After 72h shake-flask cultivation, the concentration of L(+)-lactic acid reached 74.37g/L, and the productivity was 1.03g/(L.h). Its lactic acid yield was 160% higher than that of the original one, and the mutant strain has high genetic stability. (authors)

Characteristics of lactic acid bacteria isolates and their effect on silage fermentation of fruit residues.

Science.gov (United States)

Yang, Jinsong; Tan, Haisheng; Cai, Yimin

2016-07-01

The natural lactic acid bacteria (LAB) population, chemical composition, and silage fermentation of fruit residues were studied. Eighty-two strains of LAB were isolated from fruit residues such as banana leaf and stem, pineapple peel, and papaya peel. All strains were gram-positive and catalase-negative bacteria, and they were divided into 7 groups (A-G) according to morphological and biochemical characters. Strains in groups A to F were rods, and group G was cocci. Group F produced gas from glucose; other groups did not. Groups A to C and F formed dl-lactic acid, whereas groups D, E, and G formed l-lactic acid. Based on the 16S rRNA gene sequence and DNA-DNA hybridization analysis, groups A to G strains were identified as Lactobacillus plantarum (54.9% of the total isolates), Lactobacillus paraplantarum (3.6%), Lactobacillus nagelii (8.5%), Lactobacillus perolens (4.9%), Lactobacillus casei (11.0%), Lactobacillus fermentum (9.8%), and Enterococcus gallinarum (7.3%), respectively. Lactobacillus plantarum and Lactobacillus casei are the most frequently isolated from fruit residues as a dominant species, and they could grow at a lower pH conditions and produce more lactic acid than other isolates. Pineapple and papaya peels contained higher crude protein (11.5-13.8%) and water-soluble carbohydrate (16.8-22.4%), but lower acid detergent fiber contents (21.2 to 26.4%) than banana stems and leaves (8.2% crude protein, 42.8% acid detergent fiber, and 5.1% water-soluble carbohydrate). Compared with banana stem and leaf silages, the pineapple and papaya peel silages were well preserved with a lower pH and higher lactate content. The study suggests that the fruit residues contain excellent LAB species and abundant feed nutrients, and that they can be preserved as silage to be potential food resources for livestock. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

2016-12-01

By-products resulting from thermo-chemical pretreatment of lignocellulose can inhibit fermentation of lignocellulosic sugars to lactic acid. Furfural is such a by-product, which is formed during acid pretreatment of lignocellulose. pH-controlled fermentations with 1 L starting volume, containing YP medium and a mixture of lignocellulosic by-products, were inoculated with precultures of Bacillus coagulans DSM2314 to which 1 g/L furfural was added. The addition of furfural to precultures resulted in an increase in L(+)-lactic acid productivity by a factor 2 to 1.39 g/L/h, an increase in lactic acid production from 54 to 71 g and an increase in conversion yields of sugar to lactic acid from 68 to 88 % W/W in subsequent fermentations. The improved performance was not caused by furfural consumption or conversion, indicating that the cells acquired a higher tolerance towards this by-product. The improvement coincided with a significant elongation of B. coagulans cells. Via RNA-Seq analysis, an upregulation of pathways involved in the synthesis of cell wall components such as bacillosamine, peptidoglycan and spermidine was observed in elongated cells. Furthermore, the gene SigB and genes promoted by SigB, such as NhaX and YsnF, were upregulated in the presence of furfural. These genes are involved in stress responses in bacilli.

Influence of rice straw-derived dissolved organic matter on lactic acid fermentation by Rhizopus oryzae.

Science.gov (United States)

Chen, Xingxuan; Wang, Xiahui; Xue, Yiyun; Zhang, Tian-Ao; Li, Yuhao; Hu, Jiajun; Tsang, Yiu Fai; Zhang, Hongsheng; Gao, Min-Tian

2018-01-31

Rice straw can be used as carbon sources for lactic acid fermentation. However, only a small amount of lactic acid is produced even though Rhizopus oryzae can consume glucose in rice straw-derived hydrolysates. This study correlated the inhibitory effect of rice straw with rice straw-derived dissolved organic matter (DOM). Lactic acid fermentations with and without DOM were conducted to investigate the effect of DOM on lactic acid fermentation by R. oryzae. Fermentation using control medium with DOM showed a similar trend to fermentation with rice straw-derived hydrolysates, showing that DOM contained the major inhibitor of rice straw. DOM assay indicated that it mainly consisted of polyphenols and polysaccharides. The addition of polyphenols and polysaccharides derived from rice straw confirmed that lactic acid fermentation was promoted by polysaccharides and significantly inhibited by polyphenols. The removal of polyphenols also improved lactic acid production. However, the loss of polysaccharides during the removal of polyphenols resulted in low glucose consumption. This study is the first to investigate the effects of rice straw-derived DOM on lactic acid fermentation by R. oryzae. The results may provide a theoretical basis for identifying inhibitors and promoters associated with lactic acid fermentation and for establishing suitable pretreatment methods. Copyright © 2018 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Vaginal pH and microbicidal lactic acid when lactobacilli dominate the microbiota.

Science.gov (United States)

O'Hanlon, Deirdre E; Moench, Thomas R; Cone, Richard A

2013-01-01

Lactic acid at sufficiently acidic pH is a potent microbicide, and lactic acid produced by vaginal lactobacilli may help protect against reproductive tract infections. However, previous observations likely underestimated healthy vaginal acidity and total lactate concentration since they failed to exclude women without a lactobacillus-dominated vaginal microbiota, and also did not account for the high carbon dioxide, low oxygen environment of the vagina. Fifty-six women with low (0-3) Nugent scores (indicating a lactobacillus-dominated vaginal microbiota) and no symptoms of reproductive tract disease or infection, provided a total of 64 cervicovaginal fluid samples using a collection method that avoided the need for sample dilution and rigorously minimized aerobic exposure. The pH of samples was measured by microelectrode immediately after collection and under a physiological vaginal concentration of CO2. Commercial enzymatic assays of total lactate and total acetate concentrations were validated for use in CVF, and compared to the more usual HPLC method. The average pH of the CVF samples was 3.5 ± 0.3 (mean ± SD), range 2.8-4.2, and the average total lactate was 1.0% ± 0.2% w/v; this is a five-fold higher average hydrogen ion concentration (lower pH) and a fivefold higher total lactate concentration than in the prior literature. The microbicidal form of lactic acid (protonated lactic acid) was therefore eleven-fold more concentrated, and a markedly more potent microbicide, than indicated by prior research. This suggests that when lactobacilli dominate the vaginal microbiota, women have significantly more lactic acid-mediated protection against infections than currently believed. Our results invite further evaluations of the prophylactic and therapeutic actions of vaginal lactic acid, whether provided in situ by endogenous lactobacilli, by probiotic lactobacilli, or by products that reinforce vaginal lactic acid.

Lactic acid delays the inflammatory response of human monocytes

Energy Technology Data Exchange (ETDEWEB)

Peter, Katrin, E-mail: katrin.peter@ukr.de [Department of Internal Medicine III, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); Rehli, Michael, E-mail: michael.rehli@ukr.de [Department of Internal Medicine III, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); RCI Regensburg Center for Interventional Immunology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); Singer, Katrin, E-mail: katrin.singer@ukr.de [Department of Internal Medicine III, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); Renner-Sattler, Kathrin, E-mail: kathrin.renner-sattler@ukr.de [Department of Internal Medicine III, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); Kreutz, Marina, E-mail: marina.kreutz@ukr.de [Department of Internal Medicine III, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany); RCI Regensburg Center for Interventional Immunology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg (Germany)

2015-02-13

Lactic acid (LA) accumulates under inflammatory conditions, e.g. in wounds or tumors, and influences local immune cell functions. We previously noted inhibitory effects of LA on glycolysis and TNF secretion of human LPS-stimulated monocytes. Here, we globally analyze the influence of LA on gene expression during monocyte activation. To separate LA-specific from lactate- or pH-effects, monocytes were treated for one or four hours with LPS in the presence of physiological concentrations of LA, sodium lactate (NaL) or acidic pH. Analyses of global gene expression profiles revealed striking effects of LA during the early stimulation phase. Up-regulation of most LPS-induced genes was significantly delayed in the presence of LA, while this inhibitory effect was attenuated in acidified samples and not detected after incubation with NaL. LA targets included genes encoding for important monocyte effector proteins like cytokines (e.g. TNF and IL-23) or chemokines (e.g. CCL2 and CCL7). LA effects were validated for several targets by quantitative RT-PCR and/or ELISA. Further analysis of LPS-signaling pathways revealed that LA delayed the phosphorylation of protein kinase B (AKT) as well as the degradation of IκBα. Consistently, the LPS-induced nuclear accumulation of NFκB was also diminished in response to LA. These results indicate that the broad effect of LA on gene expression and function of human monocytes is at least partially caused by its interference with immediate signal transduction events after activation. This mechanism might contribute to monocyte suppression in the tumor environment. - Highlights: • Lactic acid broadly delays LPS-induced gene expression in human monocytes. • Expression of important monocyte effector molecules is affected by lactic acid. • Interference of lactic acid with TLR signaling causes the delayed gene expression. • The profound effect of lactic acid might contribute to immune suppression in tumors.

Lactic acid delays the inflammatory response of human monocytes

International Nuclear Information System (INIS)

Peter, Katrin; Rehli, Michael; Singer, Katrin; Renner-Sattler, Kathrin; Kreutz, Marina

2015-01-01

Lactic acid (LA) accumulates under inflammatory conditions, e.g. in wounds or tumors, and influences local immune cell functions. We previously noted inhibitory effects of LA on glycolysis and TNF secretion of human LPS-stimulated monocytes. Here, we globally analyze the influence of LA on gene expression during monocyte activation. To separate LA-specific from lactate- or pH-effects, monocytes were treated for one or four hours with LPS in the presence of physiological concentrations of LA, sodium lactate (NaL) or acidic pH. Analyses of global gene expression profiles revealed striking effects of LA during the early stimulation phase. Up-regulation of most LPS-induced genes was significantly delayed in the presence of LA, while this inhibitory effect was attenuated in acidified samples and not detected after incubation with NaL. LA targets included genes encoding for important monocyte effector proteins like cytokines (e.g. TNF and IL-23) or chemokines (e.g. CCL2 and CCL7). LA effects were validated for several targets by quantitative RT-PCR and/or ELISA. Further analysis of LPS-signaling pathways revealed that LA delayed the phosphorylation of protein kinase B (AKT) as well as the degradation of IκBα. Consistently, the LPS-induced nuclear accumulation of NFκB was also diminished in response to LA. These results indicate that the broad effect of LA on gene expression and function of human monocytes is at least partially caused by its interference with immediate signal transduction events after activation. This mechanism might contribute to monocyte suppression in the tumor environment. - Highlights: • Lactic acid broadly delays LPS-induced gene expression in human monocytes. • Expression of important monocyte effector molecules is affected by lactic acid. • Interference of lactic acid with TLR signaling causes the delayed gene expression. • The profound effect of lactic acid might contribute to immune suppression in tumors

Characterization of lactic acid bacteria from local cow´s milk kefir

Science.gov (United States)

Ismail, YS; Yulvizar, C.; Mazhitov, B.

2018-03-01

One of products from milk fermentation is kefir. It is made by adding kefir grains which are composed of lactic acid bacteria and yeast into milk. The lactic acid bacteria are a group of bacteria that produce antimicrobial substances and able to inhibit the growth of pathogenic bacteria. In this research, the lactic acid bacteria were isolated from Aceh local cow`s milk kefir to determine the genus of the isolates. The methods used in the characterization of lactic acid bacteria are colony morphology, cell morphology, and biochemical tests which includes a catalase test; 5%, 6.5%, and 10% salt endurance tests; 37°C and 14°C temperature endurance tests, SIM test, TSIA test, MR-VP test, and O/F test. Of the four isolates found from the cow’s milk kefir, two isolates were confirmed as lactic acid bacteria (isolates SK-1 and SK-4). Both isolates are Gram positive bacteria, and have negative catalase activity. From the observations of colony morphology, cell morphology, and biochemical tests, it was found that the genus of SK-1 is Lactobacillus and the genus of SK-4 is Enterococcus.

Potential of lactic acid bacteria as suppressors of wine allergies

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Yıldırım Hatice Kalkan

2017-01-01

Full Text Available Allergens causes some symptoms as all asthma, allergic conjunctivitis, and allergic rhinitis. These symptoms are seen twice as many in women than in men. The major wine allergens reported in wines are endochitinase 4A and lipid-transfer protein (LTP. This review deal with possibilities of using lactic acid bacteria as suppressors of wine allergies. Phenolic compounds present in wines have not only antioxidant properties causing radical scavenging but also some special properties reported in many in vitro studies as regulating functions in inflammatory cells as mast cells. So what is the role of lactic acid bacteria in these cases? Lactic acid bacteria are used during malolactic fermentation step of wine production with purpose of malic acid reduction. During this bioconversion complex phenolic compounds could be hydrolysed by bacterial enzymes to their aglycone forms. Obtained aglycons could pass through the intestinal epithelium of human and allowed reduction of IgE antibody production by affecting Th1/ Th2 ratio. Considering different contents and quantities of phenols in different grape varieties and consequently in different wines more studies are required in order to determine which lactic acid bacteria and strains could be effective in suppressing wine allergens.

The effect of delignification process with alkaline peroxide on lactic acid production from furfural residues

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Yong Tang

2012-11-01

Full Text Available Furfural residues produced from the furfural industry were investigated as a substrate for lactic acid production by simultaneous saccharification and fermentation (SSF. Alkaline peroxide was used for delignification of furfural residues to improve the final lactic acid concentration. The residue was treated with 1.3% to 1.7% hydrogen peroxide at 80 °C for 1 h with a substrate concentration of 3.33%. SSF of furfural residues with different delignification degrees were carried out to evaluate the effect of delignification degree on lactic acid production. Using corn hydrolysates/ furfural residues as substrates, SSF with different media were carried out to investigate the effect of lignin on the interaction between enzymes and lactic acid bacteria. Lactic acid bacteria had a negative effect on cellulase, thus resulting in the reduction of enzyme activity. Lignin and nutrients slowed down the decreasing trend of enzyme activity. A higher delignification resulted in a slower fermentation rate and lower yield due to degradation products of lignin and the effect of lignin on the interaction between enzymes and lactic acid bacteria. For the purpose of lactic acid production, a moderate delignification (furfural residues with the lignin content of 14.8% was optimum.

OPTIMIZATION OF VEGETABLE WASTES FOR LACTIC ACID PRODUCTION: A LABORATORY SCALE APPROACH

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Sailaja Daharbha

2015-04-01

Full Text Available Vegetables wastes are organic materials which are not utilized as vegetables and are discarded at all stages of production, processing and marketing. These wastes form a major part of municipal solid wastes and are cause of foul smell and growth of microorganisms due to their high organic contents. The vegetable wastes can be utilized in many different ways to produces different products. We have shown that they can be utilized for production of lactic acid using anaerobic digestion. The 2nd day was the optimum day for recovery of lactic acid while 1:1 ratio of slurry and water was found to the best ratio for production of lactic acid from vegetable wastes. Effect of salts on lactic acid was also studied and it was found that the production decreased in all the concentrations of salts.

Silage fermentation and ruminal degradation of stylo prepared with lactic acid bacteria and cellulase.

Science.gov (United States)

Li, Mao; Zhou, Hanlin; Zi, Xuejuan; Cai, Yimin

2017-10-01

In order to improve the silage fermentation of stylo (Stylosanthes guianensis) in tropical areas, stylo silages were prepared with commercial additives Lactobacillus plantarum Chikuso-1 (CH1), L. rhamnasus Snow Lact L (SN), Acremonium cellulase (CE) and their combination as SN+CE or CH1 + CE, and the fermentation quality, chemical composition and ruminal degradation of these silages were studied. Stylo silages treated with lactic acid bacteria (LAB) or cellulase, the pH value and NH 3 -N ⁄ total-N were significantly (P fermentation and ruminal degradation than SN+CE treatment. The results confirmed that LAB or LAB plus cellulase treatment could improve the fermentation quality, chemical composition and ruminal degradation of stylo silage. Moreover, the combined treatment with LAB and cellulase may have beneficial synergistic effects on ruminal degradation. © 2017 Japanese Society of Animal Science.

Characteristics of immobilized lactobacillus delbrueckii in a liquid-solid fluidized bed bioreactor for lactic acid production

Energy Technology Data Exchange (ETDEWEB)

Wang, Henian; Seki, M.; Furusaki, S. [The Univ. of Tokyo (Japan). Faculty of Engineering

1995-04-20

A fluidized bed bioreactor was employed for lactic acid production using immobilized cells. First, the cell release rate was discussed. A liquid-solid fluidized bed reactor with immobilized cells was used to perform continuous lactic acid fermentation without any operational problems. The performance of the reactor was investigated under different conditions. Cell release rate and contribution of free cells to lactic acid production were studied quantitatively. The results showed that under low gel holdup and low dilution rate conditions, free cells played a significant role in lactic acid production. However, increasing solid holdup decreased the free cell concentration in the broth due to high lactic acid concentration and also decreased the contribution of the free cells to lactic acid production. The effects of growth nutrients on reactor performance were investigated. 16 refs., 12 figs.

Clinical Efficacy Comparison of Saccharomyces Boulardii and Lactic Acid as Probiotics in Acute Pediatric Diarrhea.

Science.gov (United States)

Asmat, Shakila; Shaukat, Fouzia; Asmat, Raheela; Bakhat, Hafiz Faiq Siddique Gul; Asmat, Tauseef M

2018-03-01

To compare the efficacy of Saccharomyces boulardii and lactic acid producing probiotics in addition to usual treatment regimen to cure diarrhea among children (6 months to 5 years of age). Randomized controlled trial. Department of Pediatrics, Sheikh Zayed Hospital, Lahore, from February to July 2015. Children suffering from acute diarrhea were orally administered Saccharomyces boulardii and lactic acid producing probiotics for 5 days. The efficacy of administered probiotics was monitored. Patients were given Saccharomyces boulardii and lactic acid producing probiotics randomly to remove the bias. Two hundred patients randomly selected for trials; out of which, 100 were treated with Saccharomyces boulardii while the other 100 were supplemented with lactic acid concomitantly along with conventional diarrhea treatment. Results indicated that Saccharomyces boulardii treatment group has significantly higher efficacy rate (45%) compared to lactic acid producing probiotics (26%). This study concluded that Saccharomyces boulardii has a better efficacy compared to lactic acid and may be adopted as a probiotic of choice.

Evaluation of different lactic acid bacterial strains for probiotic characteristics

OpenAIRE

B. Srinu,; T. Madhava Rao,; P. V. Mallikarjuna Reddy; K. Kondal Reddy

2013-01-01

Objective: The objective of the present study was to collect different Lactic acid bacterial strains from culture collection centers and screen their functional probiotic characteristics such as acid tolerance, bile tolerance, antibacterial activity and antibiotic sensitivity for their commercial use. Materials and Methods: Acid and bile tolerence of selected LAB(Lactic acid bacteria) was determined. The antibiotic resistance of Lactobacillus species was assessed using different antibiotic di...

49-60 Characterization of Lactic Acid Bacteria from Camel Milk and the

African Journals Online (AJOL)

Reviwer

bacteria in the food industry is the lactic acid bacteria. (LAB) which are used ... Weinberg et al., 2007) as well as for their preservative ... Food and Drug Administration FDA (2003). In the ... lactic acid bacteria species were characterized as fast.

Lactic acid fermentation of two sorghum varieties is not affected by ...

African Journals Online (AJOL)

The study was conducted to investigate sorghum grain variety differences in lactic acid fermentation based on their differences in phenolic contents. The study wa s conductedas a 2 x 5 x 4 factorial design with three factors: Factor 1: Sorghum variety (white and red sorghum); Factor 2: Control treatment without lactic acid ...

Fractionation for further conversion: from raw corn stover to lactic acid

Science.gov (United States)

He, Ting; Jiang, Zhicheng; Wu, Ping; Yi, Jian; Li, Jianmei; Hu, Changwei

2016-12-01

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050 M oxalic acid is used to simultaneously fractionate 88.0 wt% of hemicellulose and 89.2 wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and those with β-O-4 linkage of lignin; whereas ethanol extracts G and S units as well as the skeleton with β-5 and β-β linkages of lignin. Oxalic acid effectively catalyzes the hydrolysis of hemicellulose and breaks the intermolecular linkages between hemicellulose and lignin, therefore further promotes the release of lignin. The dissolved hemicelluloses derivatives are reprocessed to produce lactic acid obtaining a high yield of 79.6 wt% with 90% selectivity by the catalysis of MgO. The remained cellulose and recovered lignin can be used further as feedstock to produce chemicals.

Fractionation for further conversion: from raw corn stover to lactic acid

Science.gov (United States)

He, Ting; Jiang, Zhicheng; Wu, Ping; Yi, Jian; Li, Jianmei; Hu, Changwei

2016-01-01

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050 M oxalic acid is used to simultaneously fractionate 88.0 wt% of hemicellulose and 89.2 wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and those with β-O-4 linkage of lignin; whereas ethanol extracts G and S units as well as the skeleton with β-5 and β-β linkages of lignin. Oxalic acid effectively catalyzes the hydrolysis of hemicellulose and breaks the intermolecular linkages between hemicellulose and lignin, therefore further promotes the release of lignin. The dissolved hemicelluloses derivatives are reprocessed to produce lactic acid obtaining a high yield of 79.6 wt% with 90% selectivity by the catalysis of MgO. The remained cellulose and recovered lignin can be used further as feedstock to produce chemicals. PMID:27917955

Electrolytic extraction drives volatile fatty acid chain elongation through lactic acid and replaces chemical pH control in thin stillage fermentation.

Science.gov (United States)

Andersen, Stephen J; Candry, Pieter; Basadre, Thais; Khor, Way Cern; Roume, Hugo; Hernandez-Sanabria, Emma; Coma, Marta; Rabaey, Korneel

2015-01-01

Volatile fatty acids (VFA) are building blocks for the chemical industry. Sustainable, biological production is constrained by production and recovery costs, including the need for intensive pH correction. Membrane electrolysis has been developed as an in situ extraction technology tailored to the direct recovery of VFA from fermentation while stabilizing acidogenesis without caustic addition. A current applied across an anion exchange membrane reduces the fermentation broth (catholyte, water reduction: H2O + e(-) → ½ H2 + OH(-)) and drives carboxylate ions into a clean, concentrated VFA stream (anolyte, water oxidation: H2O → 2e(-) + 2 H(+) + O2). In this study, we fermented thin stillage to generate a mixed VFA extract without chemical pH control. Membrane electrolysis (0.1 A, 3.22 ± 0.60 V) extracted 28 ± 6 % of carboxylates generated per day (on a carbon basis) and completely replaced caustic control of pH, with no impact on the total carboxylate production amount or rate. Hydrogen generated from the applied current shifted the fermentation outcome from predominantly C2 and C3 VFA (64 ± 3 % of the total VFA present in the control) to majority of C4 to C6 (70 ± 12 % in the experiment), with identical proportions in the VFA acid extract. A strain related to Megasphaera elsdenii (maximum abundance of 57 %), a bacteria capable of producing mid-chain VFA at a high rate, was enriched by the applied current, alongside a stable community of Lactobacillus spp. (10 %), enabling chain elongation of VFA through lactic acid. A conversion of 30 ± 5 % VFA produced per sCOD fed (60 ± 10 % of the reactive fraction) was achieved, with a 50 ± 6 % reduction in suspended solids likely by electro-coagulation. VFA can be extracted directly from a fermentation broth by membrane electrolysis. The electrolytic water reduction products are utilized in the fermentation: OH(-) is used for pH control without added chemicals, and H2 is

Influence of polysorbate 80 and cyclopropane fatty acid synthase activity on lactic acid production by Lactobacillus casei ATCC 334 at low pH.

Science.gov (United States)

Broadbent, J R; Oberg, T S; Hughes, J E; Ward, R E; Brighton, C; Welker, D L; Steele, J L

2014-03-01

Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid's pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH₄OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8.

Treating Simple Tibia Fractures with Poly-DL-Lactic Acid Screw as a ...

African Journals Online (AJOL)

) absorbable screw as a ... fractures. Keywords: Simple tibia fracture, Fracture healing time Poly-DL-lactic acid, Poly-DL-Lactic Acid, ..... bilateral cortex of the bone due to the weak anti- ... Hu YL, Yuan WQ, Wang LF, Liu HF, Jin D. A prospective.

Lactic acid bacteria: microbiological and functional aspects

National Research Council Canada - National Science Library

Lahtinen, Sampo

2012-01-01

"Updated with the substantial progress made in lactic acid and bacteria research since the third edition, this fourth volume discusses improved insights in genetics and new molecular biological techniques...

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

OpenAIRE

Elena Dellacasa; Li Zhao; Gesheng Yang; Laura Pastorino; Gleb B. Sukhorukov

2016-01-01

The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA)n stereocomplex and the cores with and without the polymeric (PSS/PAH)n/PLL multilayer precursor (PEM). N...

Non-sterilized fermentation of high optically pure D-lactic acid by a genetically modified thermophilic Bacillus coagulans strain.

Science.gov (United States)

Zhang, Caili; Zhou, Cheng; Assavasirijinda, Nilnate; Yu, Bo; Wang, Limin; Ma, Yanhe

2017-11-25

Optically pure D-lactic acid (≥ 99%) is an important precursor of polylactic acid. However, there are relatively few studies on D-lactic acid fermentation compared with the extensive investigation of L-lactic acid production. Most lactic acid producers are mesophilic organisms. Optically pure D-lactic acid produced at high temperature not only could reduce the costs of sterilization but also could inhibit the growth of other bacteria, such as L-lactic acid producers. Thermophilic Bacillus coagulans is an excellent producer of L-lactic acid with capable of growing at 50 °C. In our previous study, the roles of two L-lactic acid dehydrogenases have been demonstrated in B. coagulans DSM1. In this study, the function of another annotated possible L-lactate dehydrogenase gene (ldhL3) was verified to be leucine dehydrogenase with an activity of 0.16 units (μmol/min) per mg protein. Furthermore, the activity of native D-lactate dehydrogenase was too low to support efficient D-lactic acid production, even under the control of strong promoter. Finally, an engineered B. coagulans D-DSM1 strain with the capacity for efficient production of D-lactic acid was constructed by deletion of two L-lactate dehydrogenases genes (ldhL1 and ldhL2) and insertion of the D-lactate dehydrogenase gene (LdldhD) from Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 at the position of ldhL1. This genetically engineered strain produced only D-lactic acid under non-sterilized condition, and finally 145 g/L of D-lactic acid was produced with an optical purity of 99.9% and a high yield of 0.98 g/g. This is the highest optically pure D-lactic acid titer produced by a thermophilic strain.

Severe Lactic Acidosis in a Patient with B-Cell Lymphoma: A Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Farn Huei Chan

2009-01-01

Full Text Available Lactic acidosis is commonly observed in clinical situations such as shock and sepsis, as a result of tissue hypoperfusion and hypoxia. Lymphoma and leukemia are among other clinical situations where lactic acidosis has been reported. We present a case of a 59-year-old female with lactic acidosis who was found to have aggressive B-cell lymphoma. There have been 29 cases of lymphoma induced lactic acidosis reported thus far; however all reported cases have abnormal vital signs or concomitant medical conditions that may lead to lactic acidosis. The pathogenesis of malignancy-induced lactic acidosis is not well understood; however associated factors include increased glycolysis, increased lactate production by cancer cells, and decreased hepatic clearance of lactate. When it occurs, lactic acidosis is a poor prognostic sign in these patients. Prompt diagnosis and treatment of underlying lymphoma or leukemia remains the only way to achieve complete resolution of lactic acidosis in these patients.

Synthesis of iron oxide nanorods via chemical scavenging and phase transformations of intermediates at ambient conditions

Energy Technology Data Exchange (ETDEWEB)

Deshmukh, Ruchi; Mehra, Anurag; Thaokar, Rochish, E-mail: rochish@che.iitb.ac.in [Indian Institute of Technology-Bombay, Department of Chemical Engineering (India)

2017-01-15

Chemically induced shape transformations of isotropic seeds, comprised of iron oxyhydroxides and iron oxide borate into nanorods, is reported. Transient growth studies show that the nanorods are formed via phase transformation and aggregation of various metastable species. Addition of tetra-methyl-ammonium hydroxide (TMAH) to the in situ synthesized seeds ensures a typical reaction pathway that favors formation of magnetite (Fe {sub 3}O{sub 4}) via the steps of chemical etching, phase transformation of intermediates, and crystal consolidation. Whereas, with addition of sodium hydroxide (NaOH), either magnetite (Fe {sub 3}O{sub 4}) or a mixture of (γ-Fe {sub 2}O{sub 3} + α-FeOOH) is obtained. The shape with both the additives is always that of nanorods. When the seeds treated with TMAH were aged in an ultrasonication bath, rods with almost twice the length and diameter (length = 2800 nm, diameter = 345 nm) are obtained as compared to the sample aged without ultrasonication (length = 1535 nm, diameter = 172 nm). The morphology of nanostructures depending upon other experimental conditions such as, aging the sample at 60 {sup ∘}C, seeds synthesized under ultrasonication/ stirring or externally added are also examined and discussed in detail. All the samples show high coercivity and strong ferromagnetic behavior at room temperature and should be promising candidates as ferro-fluids for various applications.

Quantitative analysis of the lactic acid and acetaldehyde produced by Streptococcus thermophilus and Lactobacillus bulgaricus strains isolated from traditional Turkish yogurts using HPLC.

Science.gov (United States)

Gezginc, Y; Topcal, F; Comertpay, S; Akyol, I

2015-03-01

The present study was conducted to evaluate the lactic acid- and acetaldehyde-producing abilities of lactic acid bacterial species isolated from traditionally manufactured Turkish yogurts using HPLC. The lactic acid bacterial species purified from the yogurts were the 2 most widely used species in industrial yogurt production: Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria have the ability to ferment hexose sugars homofermentatively to generate lactic acid and some carbonyl compounds, such as acetaldehyde through pyruvate metabolism. The levels of the compounds produced during fermentation influence the texture and the flavor of the yogurt and are themselves influenced by the chemical composition of the milk, processing conditions, and the metabolic activity of the starter culture. In the study, morphological, biochemical, and molecular characteristics were employed to identify the bacteria obtained from homemade yogurts produced in different regions of Turkey. A collection of 91 Strep. thermophilus and 35 L. bulgaricus strains were investigated for their lactic acid- and acetaldehyde-formation capabilities in various media such as cow milk, LM17 agar, and aerobic-anaerobic SM17 agar or de Man, Rogosa, and Sharpe agar. The amounts of the metabolites generated by each strain in all conditions were quantified by HPLC. The levels were found to vary depending on the species, the strain, and the growth conditions used. Whereas lactic acid production ranged between 0 and 77.9 mg/kg for Strep. thermophilus strains, it ranged from 0 to 103.5 mg/kg for L. bulgaricus. Correspondingly, the ability to generate acetaldehyde ranged from 0 to 105.9 mg/kg in Strep. thermophilus and from 0 to 126.9 mg/kg in L. bulgaricus. Our study constitutes the first attempt to determine characteristics of the wild strains isolated from traditional Turkish yogurts, and the approach presented here, which reveals the differences in metabolite production abilities of the

Review of the microbiological, chemical and radiolytic degradation of organic material likely to be present in intermediate level and low level radioactive wastes

International Nuclear Information System (INIS)

Greenfield, B.F.; Rosevear, A.; Williams, S.J.

1990-11-01

A review has been made of the microbiological, chemical and radiolytic degradation of the solid organic materials likely to be present in intermediate-level and low-level radioactive wastes. Possible interactions between the three routes for degradation are also discussed. Attention is focussed on the generation of water-soluble degradation products which may form complexes with radioelements. The effects of complexation on radioelement solubility and sorption are considered. Recommendations are made for areas of further research. (author)

Amino acids transport in lactic streptococci

NARCIS (Netherlands)

Driessen, Arnold Jacob Mathieu

1987-01-01

Lactic streptococci are extremely fastidious bacteria. For growth an exogenous source of amino acids and other nutrients is essential. The amino acid requirement in milk is fulfilled by the milk-protein casein, which is degraded by sequential hydrolysis, involving proteases and peptidases. ... Zie:

Proteolytic enzymes of lactic acid bacteria

NARCIS (Netherlands)

Law, J; Haandrikman, A

The proteolytic system of lactic acid bacteria is essential for their growth in milk and contributes significantly to flavour development in fermented milk products where these microorganisms are used as starter cultures. The proteolytic system is composed of proteinases which initially cleave the

VHTR engineering design study: intermediate heat exchanger program. Final report

International Nuclear Information System (INIS)

1976-11-01

The work reported is the result of a follow-on program to earlier Very High Temperature Reactor (VHTR) studies. The primary use of the VHTR is to provide heat for various industrial processes, such as hydrocarbon reforming and coal gasification. For many processes the use of an intermediate heat transfer barrier between the reactor coolant and the process is desirable; for some processes it is mandatory. Various intermediate heat exchanger (IHX) concepts for the VHTR were investigated with respect to safety, cost, and engineering design considerations. The reference processes chosen were steam-hydrocarbon reforming, with emphasis on the chemical heat pipe, and steam gasification of coal. The study investigates the critically important area of heat transfer between the reactor coolant, helium, and the various chemical processes

Lactose behaviour in the presence of lactic acid and calcium.

Science.gov (United States)

Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

2016-08-01

Physical properties of lactose appeared influenced by presence of lactic acid in the system. Some other components such as Ca may further attenuate lactose behaviour and impact its phase transition. A model-based study was thus implemented with varying concentrations of Ca (0·12, 0·072 or 0·035% w/w) and lactic acid (0·05, 0·2, 0·4 or 1% w/w) in establishing the effects of these two main acid whey constituents on lactose phase behaviour. Concentrated solutions (50% w/w) containing lactose, lactic acid and Ca were analysed for thermal behaviour and structural changes by Differential Scanning Colorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. Presence of 1% (w/w) lactic acid and 0·12% (w/w) Ca in lactose solution significantly increased the evaporation enthalpy of water, delayed and increased the energy required for lactose crystallisation as compared to pure lactose. FTIR analysis indicated a strong hydration layer surrounding lactose molecules, restricting water mobility and/or inducing structural changes of lactose, hindering its crystallisation. The formation of calcium lactate, which restricts the diffusion of lactose molecules, is also partly responsible. It appears that Ca removal from acid whey may be a necessary step in improving the processability of acid whey.

The MHD intermediate shock interaction with an intermediate wave: Are intermediate shocks physical?

International Nuclear Information System (INIS)

Wu, C.C.

1988-01-01

Contrary to the usual belief that MHD intermediate shocks are extraneous, the authors have recently shown by numerical solutions of dissipative MHD equations that intermediate shocks are admissible and can be formed through nonlinear steepening from a continuous wave. In this paper, he clarifies the differences between the conventional view and the results by studying the interaction of an MHD intermediate shock with an intermediate wave. The study reaffirms his results. In addition, the study shows that there exists a larger class of shocklike solutions in the time-dependent dissiaptive MHD equations than are given by the MHD Rankine-Hugoniot relations. it also suggests a mechanism for forming rotational discontinuities through the interaction of an intermediate shock with an intermediate wave. The results are of importance not only to the MHD shock theory but also to studies such as magnetic field reconnection models

Metformin and lactic acidosis : cause or coincidence? A review of case reports

NARCIS (Netherlands)

Stades, AME; Heikens, JT; Erkelens, DW; Holleman, F; Hoekstra, JBL

Objective. Metformin has been associated with the serious side-effect lactic acidosis. However, it remains unclear whether the use of metformin was a cause or a coincidence in lactic acidosis. Design. A literature search of the Index Medicus (1959-66) and of the databases Embase, Medline, Medline

Metformin and lactic acidosis: cause or coincidence? A review of case reports

NARCIS (Netherlands)

Stades, A. M. E.; Heikens, J. T.; Erkelens, D. W.; Holleman, F.; Hoekstra, J. B. L.

2004-01-01

Objective. Metformin has been associated with the serious side-effect lactic acidosis. However, it remains unclear whether the use of metformin was a cause or a coincidence in lactic acidosis. Design. A literature search of the Index Medicus (1959-66) and of the databases Embase, Medline, Medline

Chirality Matters: Synthesis and Consumption of the d-Enantiomer of Lactic Acid by Synechocystis sp. Strain PCC6803

NARCIS (Netherlands)

Angermayr, S.A.; van der Woude, A.D.; Correddu, D.; Kern, R.; Hagemann, M.; Hellingwerf, K.J.

2015-01-01

Both enantiomers of lactic acid, l-lactic acid and d-lactic acid, can be produced in a sustainable way by a photosynthetic microbial cell factory and thus from CO2, sunlight, and water. Several properties of polylactic acid (a polyester of polymerized lactic acid) depend on the controlled blend of

The inhibitory activity of Lactic acid bacteria isolated from fresh cow cheese

Directory of Open Access Journals (Sweden)

Nevijo Zdolec

2007-04-01

Full Text Available Lactic acid bacteria are the constituent part of milk microbial flora that could influence the safety of dairy products due production of organic acids, hydrogen peroxide, carbon dioxide and bacteriocins. Taking this in consideration, the objective of this study was to investigate the composition of lactic acid bacteria population in fresh cow cheeses taken from local markets, as well as their antimicrobial capacity. Lactic acid bacteria counts were determined according to ISO 1524:1998 method, biochemical determination using API 50 CHL system, and inhibitory activity against L. monocytogenes NCTC 10527 by agar well diffusion assay. Lactic acid bacteria count in fresh cow cheeses (n=10 ranged from 5.87 to 8.38 log10 CFU g-1. Among 52 MRS isolates collected, 61.54 % were assigned to the Lactococcus lactis subsp. Lactis species, 23.07 % Lactobacillus helveticus, 11.54 % Leuconostoc mesenteroides subsp. cremoris and 3.85 % Leuconostoc mesenteroides subsp. mesenteroides. Antilisterial activity was found in 18 isolates.

Microbiological and chemical characteristics of Brazilian kefir during fermentation and storage processes.

Science.gov (United States)

Leite, A M O; Leite, D C A; Del Aguila, E M; Alvares, T S; Peixoto, R S; Miguel, M A L; Silva, J T; Paschoalin, V M F

2013-07-01

The microbial community composition and chemical characteristics of a Brazilian milk kefir sample produced during its manufacturing and refrigerated storage were investigated by culture-dependent and -independent methods and HPLC. Lactococcus lactis ssp. cremoris and ssp. lactis, Leuconostoc mesenteroides, Acetobacter lovaniensis, and Saccharomyces cerevisiae were isolated, whereas the detected bands on denaturing gel gradient electrophoresis corresponded to Lactobacillus kefiranofaciens, Lactobacillus kefiri, Lactobacillus parakefiri, and S. cerevisiae. After fermentation, lactic acid bacteria were present at levels of 10 log units, whereas acetic acid bacteria and yeast were present at levels of 7.8 and 6 log units, respectively. The lactic acid bacteria and yeast counts remained constant, whereas acetic acid bacteria counts decreased to 7.2 log units during storage. From fermentation to final storage, the pH, lactose content and citric acid of the kefir beverage decreased, followed by an increase in the concentrations of glucose, galactose, ethanol, and lactic, acetic, butyric, and propionic acids. These microbiological and chemical characteristics contribute to the unique taste and aroma of kefir. This research may serve as a basis for the future industrial production of this beverage in Brazil. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Continuous D-lactic acid production by a novel thermotolerant Lactobacillus delbrueckii subsp. lactis QU 41.

Science.gov (United States)

Tashiro, Yukihiro; Kaneko, Wataru; Sun, Yanqi; Shibata, Keisuke; Inokuma, Kentaro; Zendo, Takeshi; Sonomoto, Kenji

2011-03-01

We isolated and characterized a D-lactic acid-producing lactic acid bacterium (D-LAB), identified as Lactobacillus delbrueckii subsp. lactis QU 41. When compared to Lactobacillus coryniformis subsp. torquens JCM 1166 (T) and L. delbrueckii subsp. lactis JCM 1248 (T), which are also known as D-LAB, the QU 41 strain exhibited a high thermotolerance and produced D-lactic acid at temperatures of 50 °C and higher. In order to optimize the culture conditions of the QU 41 strain, we examined the effects of pH control, temperature, neutralizing reagent, and initial glucose concentration on D-lactic acid production in batch cultures. It was found that the optimal production of 20.1 g/l D-lactic acid was acquired with high optical purity (>99.9% of D-lactic acid) in a pH 6.0-controlled batch culture, by adding ammonium hydroxide as a neutralizing reagent, at 43 °C in MRS medium containing 20 g/l glucose. As a result of product inhibition and low cell density, continuous cultures were investigated using a microfiltration membrane module to recycle flow-through cells in order to improve D-lactic acid productivity. At a dilution rate of 0.87 h(-1), the high cell density continuous culture exhibited the highest D-lactic acid productivity of 18.0 g/l/h with a high yield (ca. 1.0 g/g consumed glucose) and a low residual glucose (<0.1 g/l) in comparison with systems published to date.

Potential Use of Gelidium amansii Acid Hydrolysate for Lactic Acid Production by Lactobacillus rhamnosus

Directory of Open Access Journals (Sweden)

Sung-Soo Jang

2013-01-01

Full Text Available Galactose and glucose are the main monosaccharides produced from the saccharification of Gelidium amansii. They were hydrolysed with 3 % (by volume H2SO4 at 140 °C for 5 min and obtained at concentrations of 19.60 and 10.21 g/L, respectively. G. amansii hydrolysate (5 %, by mass per volume was used as a substrate for L(+-lactic acid production by Lactobacillus rhamnosus. The maximum lactic acid yield (YP/S was 42.03 % with optical purity of 84.54 %. Lactic acid produced from G. amansii hydrolysate can be applicable, among others, for the production of lactic acid esters, like ethyl or methyl lactate, and disinfectant in seaweed cultivation.

Effect of Different Storage Period on Lactic Acid Bacterias from Goji Yogurt and Goji Yogurt with Honey

Directory of Open Access Journals (Sweden)

Ancuta M. Rotar

2014-05-01

Full Text Available Lactic acid bacterias (LAB: Streptococcus thermophilus-ST, Lactobacillus bulgaricus-LB are well known in the food technology area for their ability to produce lactic acid (LA from carbohydrates throught fermentation. In case of goji yogurt the interaction between the two species of LAB has influence on the fermentation period and LA quantity. LAB’s are widely used in the food industry because their growth in the dairy products lowers the carbohydrate content, they can also drop the pH values under 4.0, values were common pathogens are inhibited, and because of all these properties they are capable to prolong the shelf life. The present study aims to observe the evolution of LAB’s – ST and LB, from goji yogurt (7% (A and goji yogurt (7% with honey (B during the shelf life in corelation with other physico-chemical properties such as sugar content, fat content and dry matter. The samples for the evaluation were taken in the first day of storage, at the middle of storage period and in the last day of storage.

Screening local Lactobacilli from Iran in terms of production of lactic acid and identification of superior strains

Directory of Open Access Journals (Sweden)

Fatemeh Soleimanifard

2015-12-01

Full Text Available Introduction: Lactobacilli are a group of lactic acid bacteria that their final product of fermentation is lactic acid. The objective of this research is selection of local Lactobacilli producing L (+ lactic acid. Materials and methods: In this research the local strains were screened based on the ability to produce lactic acid. The screening was performed in two stages. The first stage was the titration method and the second stage was the enzymatic method. The superior strains obtained from titration method were selected to do enzymatic test. Finally, the superior strains in the second stage (enzymatic which had the ability to produce L(+ lactic acid were identified by biochemical tests. Then, molecular identification of strains was performed by using 16S rRNA sequencing. Results: In this study, the ability of 79 strains of local Lactobacilli in terms of production of lactic acid was studied. The highest and lowest rates of lactic acid production was 34.8 and 12.4 mg/g. Superior Lactobacilli in terms of production of lactic acid ability of producing had an optical isomer L(+, the highest levels of L(+ lactic acid were with 3.99 and the lowest amount equal to 1.03 mg/g. The biochemical and molecular identification of superior strains showed that strains are Lactobacillus paracasei. Then the sequences of 16S rRNA of superior strains were reported in NCBI with accession numbers KF735654، KF735655، KJ508201and KJ508202. Discussion and conclusion: The amounts of lactic acid production by local Lactobacilli were very different and producing some of these strains on available reports showed more products. The results of this research suggest the use of superior strains of Lactobacilli for production of pure L(+ lactic acid.

Availability of lignocellulosic feedstocks for lactic acid production - Feedstock availability, lactic acid production potential and selection criteria

NARCIS (Netherlands)

Bakker, R.R.C.

2013-01-01

The overall objective of this study is to assess the worldwide availability and suitability of agricultural residues for lactic acid production, based on fermentation of carbohydrates. The study focuses on lignocellulosic biomass that is produced as a by-product of agricultural production. The

Characterization of the spoilage lactic acid bacteria in “sliced vacuum-packed cooked ham”

Science.gov (United States)

Kalschne, Daneysa Lahis; Womer, Rute; Mattana, Ademir; Sarmento, Cleonice Mendes Pereira; Colla, Luciane Maria; Colla, Eliane

2015-01-01

The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc / Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus , following by Lactobacillus sakei and Leuconostoc mesentereoides ; the Enterococcus sp. was not present in the samples. PMID:26221105

Antifungal Poly(lactic acid Films Containing Thymol and Carvone

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Boonruang Kanchana

2016-01-01

Full Text Available The goal of this study was to develop antifungal poly(lactic acid films for food packaging applications. The antifungal compounds, thymol and R-(--carvone were incorporated into poly(lactic acid (PLA-based polymer at 10, 15 and 20% by weight. Film converting process consists of three steps including melt blending, sheet extrusion and biaxial stretching. The incorporation of antifungal compounds into the polymer matrix resulted in decreased Tg and Tm, increased gas permeabilility, reduced tensile strength and increased elongation at break of the antifungal PLA films.

Multidrug transporters in lactic acid bacteria

NARCIS (Netherlands)

Mazurkiewicz, P; Sakamoto, K; Poelarends, GJ; Konings, WN

Gram-positive lactic acid bacteria possess several Multi-Drug Resistance systems (MDRs) that excrete out of the cell a wide variety of mainly cationic lipophilic cytotoxic compounds as well as many clinically relevant antibiotics. These MDRs are either proton/drug antiporters belonging to the major

Chemical polishing of partially oxidized T-111 alloy

International Nuclear Information System (INIS)

Teaney, P.E.

1974-01-01

The specimens were pressure-mounted in Bakelite and ground through 600 grit on silicon carbide papers. The specimens were rough-polished on a vibratory polisher for 4 to 6 h, using a water slurry of one micron alumina on Texmet, followed by 0.3-μ alumina on Texmet overnight. Final polishing was accomplished by continuous swabbing with a chemical polish. A chemical polish consisting of ten parts lactic acid, four parts nitric acid, and four parts hydrofluoric acid worked well for the T-111 parent material specimens; however, in the partially oxidized specimens, considerable pitting and staining occurred in the oxygen-affected zone and in the transition zone between the oxygen-affected zone and the parent material. A chemical polish was developed for the partially oxidized specimens by adjusting the ratio of the acids to ten parts lactic acid, two parts nitric acid, and two parts hydrofluoric acid. This slowed the chemical attack on the oxygen-affected zone considerably and, with continuous swabbing, the pitting and stain could be avoided. The specimens were rinsed and checked occasionally on the metallograph to determine when the proper polish had been obtained. Some specimens required intermittent polishing times up to 1 / 2 hour. No relationship could be established between the oxygen content of the specimen and the time required for chemical polishing in the partially oxidized specimens. However, the microstructure of the transition zone was the most difficult to obtain, and specimens with uniform reaction zones across the width of the specimen polished quicker than those with the transition zone

Reduction of Campylobacter jejuni on chicken wings by chemical treatments.

Science.gov (United States)

Zhao, Tong; Doyle, Michael P

2006-04-01

Eight chemicals, including glycerol monolaurate, hydrogen peroxide, acetic acid, lactic acid, sodium benzoate, sodium chlorate, sodium carbonate, and sodium hydroxide, were tested individually or in combination for their ability to inactivate Campylobacter jejuni at 4 degrees C in suspension. Results showed that treatment for up to 20 min with 0.01% glycerol monolaurate, 0.1% sodium benzoate, 50 or 100 mM sodium chlorate, or 1% lactic acid did not substantially (5 log CFU/ml within 2 min. A combination of 0.5% acetic acid plus 0.05% potassium sorbate or 0.5% acetic acid plus 0.05% sodium benzoate reduced C. jejuni populations by >5 log CFU/ml within 1 min; however, substituting 0.5% lactic acid for 0.5% acetic acid was not effective, with a reduction of C. jejuni of 5 log CFU/ml within 1 min. All chemicals or chemical combinations for which there was a >5-log/ml reduction of C. jejuni in suspension were further evaluated for C. jejuni inactivation on chicken wings. Treatments at 4 degrees C of 2% acetic acid, 100 mM sodium carbonate, or 0.1 N sodium hydroxide for up to 45 s reduced C. jejuni populations by ca. 1.4, 1.6, or 3.5 log CFU/g, respectively. Treatment with ACS-LA at 4 degrees C for 15 s reduced C. jejuni by >5 log CFU/g to an undetectable level. The ACS-LA treatment was highly effective in chilled water at killing C. jejuni on chicken and, if recycled, may be a useful treatment in chill water tanks for poultry processors to reduce campylobacters on poultry skin after slaughter.

Simultaneous production of l-lactic acid with high optical activity and a soil amendment with food waste that demonstrates plant growth promoting activity.

Science.gov (United States)

Kitpreechavanich, Vichien; Hayami, Arisa; Talek, Anfal; Chin, Clament Fui Seung; Tashiro, Yukihiro; Sakai, Kenji

2016-07-01

A unique method to produce highly optically-active l-lactic acid and soil amendments that promote plant growth from food waste was proposed. Three Bacillus strains Bacillus subtilis KBKU21, B. subtilis N3-9 and Bacillus coagulans T27, were used. Strain KBKU21 accumulated 36.9 g/L l-lactic acid with 95.7% optical activity and 98.2% l-lactic acid selectivity when fermented at 43°C for 84 h in a model kitchen refuse (MKR) medium. Residual precipitate fraction (anaerobically-fermented MKR (AFM) compost) analysis revealed 4.60%, 0.70% and 0.75% of nitrogen (as N), phosphorous (as P2O5), and potassium (as K2O), respectively. Additionally, the carbon to nitrogen ratio decreased from 13.3 to 10.6. AFM compost with KBKU21 promoted plant growth parameters, including leaf length, plant height and fresh weight of Brassica rapa (Komatsuna), than that by chemical fertilizers or commercial compost. The concept provides an incentive for the complete recycling of food waste, contributing towards a sustainable production system. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Stimulation of Lactic Acid Bacteria by a Micrococcus Isolate: Evidence for Multiple Effects

Science.gov (United States)

Nath, K. R.; Wagner, B. J.

1973-01-01

Growth of, and rate of acid production by, six cultures of lactic acid bacteria were increased in the presence of Micrococcus isolate F4 or a preparation of its capsular material. Concentrations of hydrogen peroxide found in pure cultures of the lactic acid bacteria were not detectable, or were greatly reduced, in mixed culture with Micrococcus isolate F4. The capsular material was not as effective as whole cells in preventing accumulation of H2O2. Catalase stimulated growth of, and the rate of acid production by, the lactic acid bacteria, but not to the same extent as Micrococcus isolate F4 in some cultures. The existence of two mechanisms for micrococcal stimulation of the lactic acid bacteria is postulated. One mechanism involves removal of H2O2; the other has not been characterized. PMID:4199337

Influence of Heavy Metal Powders on Rheological Properties of Poly(Lactic Acid)

Science.gov (United States)

Lebedev, S. M.; Gefle, O. S.; Amitov, E. T.; Berchuk, D. Yu.; Zhuravlev, D. V.

2017-08-01

Main properties of poly(lactic acid) (PLA) and composite materials on its basis filled with tungsten and lead powders are investigated. An anomalous decrease of the viscosity of melts of poly(lactic acid)/tungsten and poly(lactic acid)/lead composites is detected. The methods of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and IR spectroscopy are used for investigation. It is shown that the temperature at which the composites filled with tungsten and lead begin to melt decreases by more than 8 and 3°C in comparison with neat PLA. Our investigations show impossibility of preparing radiation resistant polymer composites based on PLA filled with tungsten and lead powders.

Arctic Intermediate Water in the Nordic Seas, 1991-2009

Science.gov (United States)

Jeansson, Emil; Olsen, Are; Jutterström, Sara

2017-10-01

The evolution of the different types of Arctic Intermediate Water (AIW) in the Nordic Seas is evaluated and compared utilising hydro-chemical data from 1991 to 2009. It has been suggested that these waters are important components of the Norwegian Sea Arctic Intermediate Water (NSAIW), and of the dense overflows to the North Atlantic. Thus, it is important to understand how their properties and distribution vary with time. The AIWs from the Greenland and Iceland Seas, show different degrees of variability during the studied period; however, only the Greenland Sea Arctic Intermediate Water (GSAIW) shows an increasing temperature and salinity throughout the 2000s, which considerably changed the properties of this water mass. Optimum multiparameter (OMP) analysis was conducted to assess the sources of the NSAIW. The analysis shows that the Iceland Sea Arctic Intermediate Water (ISAIW) and the GSAIW both contribute to NSAIW, at different densities corresponding to their respective density range. This illustrates that they flow largely isopycnally from their source regions to the Norwegian Sea. The main source of the NSAIW, however, is the upper Polar Deep Water, which explains the lower concentrations of oxygen and chlorofluorocarbons, and higher salinity and nutrient concentrations of the NSAIW layer compared with the ISAIW and GSAIW. This shows how vital it is to include chemical tracers in any water mass analysis to correctly assess the sources of the water mass being studied.

Influence of different sterilization processes on the properties of commercial poly(lactic acid)

International Nuclear Information System (INIS)

Savaris, M.; Santos, V. dos; Brandalise, R.N.

2016-01-01

This study aims at analyzing the modifications in the morphological, physical, chemical and thermal properties of commercial poly(lactic acid) (PLA) films after exposure to five different sterilization processes. Films were obtained by compression molding, hygienized and sterilized by ethylene oxide (SEtO), hydrogen peroxide plasma (SH 2 O 2 ), saturated steam (SSS), electron beam radiation (SEB) and gamma radiation (SGR). The samples of PLA SEtO , PLA SH2O2 , PLA SEB and PLA SGR exhibited thermal and physical changes after being submitted to sterilization processes. PLA SSS showed morphological, chemical, thermal and physical changes. It is concluded that processes by SEtO, SH 2 O 2 , SEB and EGR can be applied for the sterilization of PLA films and the SSS process is not recommended in view of the data obtained and test conditions reported in this study for PLA films. - Highlights: • PLA was subjected to five different sterilization process. • All sterilization processes do not changed the hydrophilicity of PLA. • Morphological, chemical, physical and thermal changes were observed for the PLA SSS . • The sterilization by saturated steam is not recommended to sterilize PLA.

Isolation of lactic acid bacteria with potential protective culture characteristics from fruits

Science.gov (United States)

Hashim, Nurul Huda; Sani, Norrakiah Abdullah

2015-09-01

Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.

Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells.

Science.gov (United States)

Yamane, Takuya; Sakamoto, Tatsuji; Nakagaki, Takenori; Nakano, Yoshihisa

2018-03-27

The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis , Lactococcus . lactis subsp. Cremoris , Lactococcus. Lactis subsp. Lactis biovar diacetylactis , Lactobacillus plantarum , Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei . In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma) increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity.

[Lactic acidosis in the postictal state].

Science.gov (United States)

van Rooij, Femke J M; Admiraal-van de Pas, Yvonne

2015-01-01

Epilepsy is a neurological disorder with an annual incidence in the Netherlands of 30 per 100,000 people. We present two cases of a patient admitted to the emergency department upon experiencing a generalized seizure. In each case, severe metabolic lactic acidosis was identified through routine laboratory diagnostics. Based on their clinical presentation, we had no reasons to suspect another cause of this severe acidosis apart from the seizure. We repeated arterial blood sample one to two hours later and found that both pH and lactate were normalized. Severe lactic acidosis may occur in patients who experience seizures but otherwise do not require treatment. Taking an arterial blood sample from these patients in the emergency setting will be of limited value, because in most patients hyperlactatemia in the postictal state is self-limiting. In some patients, however, a persistent hyperlactatemia may indicate a serious underlying pathology. It is therefore advisable to repeat an arterial blood sample a few hours later.

Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

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Andrea Komesu

2017-01-01

Full Text Available Actually, there is a growing interest in the biotechnological production of lactic acid by fermentation aiming to substitute fossil fuel routes. The development of an efficient method for its separation and purification from fermentation broth is very important to assure the economic viability of production. Due to its high reactivity and tendency to decompose at high temperatures, the study of lactic acid thermal behavior is essential for its separation processes and potential application. In the present study, differential scanning calorimetry (DSC analyses showed endothermic peaks related to the process of evaporation. Data of thermogravimetry (TG/DTG were correlated to Arrhenius and Kissinger equations to provide the evaporation kinetic parameters and used to determine the vaporization enthalpy. Activation energies were 51.08 and 48.37 kJ·mol−1 and frequency values were 859.97 and 968.81 s−1 obtained by Arrhenius and Kissinger equations, respectively. Thermogravimetry, coupled with mass spectroscopy (TG-MS, provided useful information about decomposition products when lactic acid was heated at 573 K for approximately 30 min.

Antioxidant activity of probiotic lactic acid bacteria isolated from Mongolian airag

OpenAIRE

E Uugantsetseg; B Batjargal

2014-01-01

This research aimed to determine the antioxidant activity of probiotic lactic acid bacteria isolated from airag. In this study, 42 lactic acid bacteria were isolated from Mongolian airag. All isolates were identified by using morphological, biochemical and physiological methods. The isolated bacteria were studied for antagonistic effects on Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, 22 strains showed antibacterial activity. When we examined thei...

Water-lactose behavior as a function of concentration and presence of lactic acid in lactose model systems.

Science.gov (United States)

Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

2015-12-01

The presence of high amounts of lactic acid in acid whey restricts its ability to be further processed because lactose appears to remain in its amorphous form. A systematic study is lacking in this regard especially during the concentration step. Hence, the main aim of the study was to establish the structure and behavior of water molecules surrounding lactose in the presence of 1% (wt/wt) lactic acid at a concentration up to 50% (wt/wt). Furthermore, the crystallization nature of freeze-dried lactose with or without lactic acid was established using differential scanning calorimetry and Fourier transform infrared spectroscopy. Two mechanisms were proposed to describe the behavior of water molecules around lactose molecules during the concentration of pure lactose and lactose solutions with lactic acid. Pure lactose solution exhibited a water evaporation enthalpy of ~679 J·g(-1), whereas lactose+ lactic acid solution resulted in ~965 J·g(-1) at a 50% (wt/wt) concentration. This indicates a greater energy requirement for water removal around lactose in the presence of lactic acid. Higher crystallization temperatures were observed with the presence of lactic acid, indicating a delay in crystallization. Furthermore, less crystalline lactose (~12%) was obtained in the presence of lactic acid, indicating high amorphous nature compared with pure lactose where ~50% crystallinity was obtained. The Fourier transform infrared spectra revealed that the strong hydration layer consisting lactic acid and H3O(+) ions surrounded lactose molecules via strong H bonds, which restricted water mobility, induced a change in structure of lactose, or both, creating unfavorable conditions for lactose crystallization. Thus, partial or complete removal of lactic acid from acid whey may be the first step toward improving the ability of acid whey to be processed. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Sodium bicarbonate treatment during transient or sustained lactic acidemia in normoxic and normotensive rats.

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Franco Valenza

Full Text Available INTRODUCTION: Lactic acidosis is a frequent cause of poor outcome in the intensive care settings. We set up an experimental model of lactic acid infusion in normoxic and normotensive rats to investigate the systemic effects of lactic acidemia per se without the confounding factor of an underlying organic cause of acidosis. METHODOLOGY: Sprague Dawley rats underwent a primed endovenous infusion of L(+ lactic acid during general anesthesia. Normoxic and normotensive animals were then randomized to the following study groups (n = 8 per group: S sustained infusion of lactic acid, S+B sustained infusion+sodium bicarbonate, T transient infusion, T+B transient infusion+sodium bicarbonate. Hemodynamic, respiratory and acid-base parameters were measured over time. Lactate pharmacokinetics and muscle phosphofructokinase enzyme's activity were also measured. PRINCIPAL FINDINGS: Following lactic acid infusion blood lactate rose (P<0.05, pH (P<0.05 and strong ion difference (P<0.05 drop. Some rats developed hemodynamic instability during the primed infusion of lactic acid. In the normoxic and normotensive animals bicarbonate treatment normalized pH during sustained infusion of lactic acid (from 7.22 ± 0.02 to 7.36 ± 0.04, P<0.05 while overshoot to alkalemic values when the infusion was transient (from 7.24 ± 0.01 to 7.53 ± 0.03, P<0.05. When acid load was interrupted bicarbonate infusion affected lactate wash-out kinetics (P<0.05 so that blood lactate was higher (2.9 ± 1 mmol/l vs. 1.0 ± 0.2, P<0.05, group T vs. T+B respectively. The activity of phosphofructokinase enzyme was correlated with blood pH (R2 = 0.475, P<0.05. CONCLUSIONS: pH decreased with acid infusion and rose with bicarbonate administration but the effects of bicarbonate infusion on pH differed under a persistent or transient acid load. Alkalization affected the rate of lactate disposal during the transient acid load.

Neuropathic Pain Following Poly-L-Lactic Acid (Sculptra) Injection.

Science.gov (United States)

Vrcek, Ivan; El-Sawy, Tarek; Chou, Eva; Allen, Theresa; Nakra, Tanuj

Injectable fillers have become a prevalent means of facial rejuvenation and volume expansion. While typically well tolerated, serious complications have been reported. The authors present a case in which an otherwise healthy female with a history of multiple filler injections including poly-L-lactic acid, developed 3 weeks of neuropathic pain in the left temporal fossa following injection. To the best of the authors knowledge, neuropathic pain has not been reported as a complication following poly-L-lactic acid injection. The patient was treated with an injection of steroid and long-acting anesthetic with resolution of symptoms.

Highly efficient production of L-lactic acid from xylose by newly isolated Bacillus coagulans C106.

Science.gov (United States)

Ye, Lidan; Zhou, Xingding; Hudari, Mohammad Sufian Bin; Li, Zhi; Wu, Jin Chuan

2013-03-01

Cost-effective production of optically pure lactic acid from lignocellulose sugars is commercially attractive but challenging. Bacillus coagulans C106 was isolated from environment and used to produce l-lactic acid from xylose at 50°C and pH 6.0 in mineral salts medium containing 1-2% (w/v) of yeast extract without sterilizing the medium before fermentation. In batch fermentation with 85g/L of xylose, lactic acid titer and productivity reached 83.6g/L and 7.5g/Lh, respectively. When fed-batch (120+80+60g/L) fermentation was applied, they reached 215.7g/L and 4.0g/Lh, respectively. In both cases, the lactic acid yield and optical purity reached 95% and 99.6%, respectively. The lactic acid titer and productivity on xylose are the highest among those ever reported. Ca(OH)2 was found to be a better neutralizing agent than NaOH in terms of its giving higher lactic acid titer (1.2-fold) and productivity (1.8-fold) under the same conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

Science.gov (United States)

Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

2014-12-01

The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Modification of Cassava Starch Using Lactic Acid Hydrolysis in The Rotary-UV Dryer to Improve Physichocemical Properties

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Sumardiono Siswo

2018-01-01

Full Text Available Food security should be supported in an effort to utilize local products into import substitution products. Cassava starch has the potential to be developed into semi-finished products in the form of flour or starch which does not contain gluten but can inflate large baking process, potentially as a substitute for wheat flour-the main ingredient for making bread. The characteristic of the starch is influenced by the type of starch composition and structure. Natural starch has physicochemical properties i.e. a long time cooking and pasta formed hard. These constraints allow us to modify cassava starch by a combination of lactic acid hydrolysis and drying with rotary UV system. Modified cassava starch is expected to be used as a substitute for wheat flour. The aim of the research which is a combination of lactic acid hydrolysis and drying using a rotary UV system is to examine the optimum operating conditions in the drying process of starch hydrolysis with parameter the physicochemical and rheological properties of modified cassava starch. The initial process study is to hydrolyze cassava starch using lactic acid. Furthermore, hydrolyzed cassava starch is then dried using UV light in the rotary dryers system. There are a variety of changing variables, i.e. time of irradiation cassava starch-lactic acid hydrolysis products in the rotary UV light and air drying temperature. The research results show that modified starch has a better characteristic than the natural starch. From the analysis, the best point of swelling power, solubility and baking expansion is consequently 15.62 g/g; 24.19 %; 2.21 ml/gr. The FTIR result shows that there is no significant difference of the chemical structure because the starch modification only change the physical characteristics. From the SEM analysis, we can know that the size of the starch’s granule changes between the natural starch and the modified starch..

Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells

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Takuya Yamane

2018-03-01

Full Text Available The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis, Lactococcus. lactis subsp. Cremoris, Lactococcus. Lactis subsp. Lactis biovar diacetylactis, Lactobacillus plantarum, Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei. In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cells and colorectal tumor HCT116 cells. Furthermore, levels of mRNA expression and secretion of IFN-γ (interferon gamma increased in KHYG-1 cells that had been treated with the six lactic acid bacteria mixture from kefir. The results suggest that the six lactic acid bacteria mixture from kefir has strong effects on natural immunity and tumor cell cytotoxicity.

Fabrication of high-performance poly(l-lactic acid)/lignin-graft-poly(d-lactic acid) stereocomplex films.

Science.gov (United States)

Liu, Rui; Dai, Lin; Hu, Li-Qiu; Zhou, Wen-Qin; Si, Chuan-Ling

2017-11-01

The need for green renewable alternatives such as lignin to traditional fillers has driven recent interest in polylactic acid blend materials. Herein, lignin-graft-polylactic acid copolymers (LG-g-PDLA, LG-g-PDLLA, and LG-g-PLLA) have been synthesized via ring-opening polymerization of d-, dl-, and l-lactic acid. Then poly(l-lactic acid)/lignin-graft-polylactic acid (PLLA/LG-g-PDLA, /LG-g-PDLLA, and /LG-g-PLLA) complex films have been prepared. The results showed that, compared with LG-g-PDLA and LG-g-PLLA, a small amount of LG-g-PDLA addition could improve the crystallization rate, reduce the glass transition temperature and cold crystallization temperature of PLLA due to the stereocomplex crystallites. The thermal stability, tensile strength and strain of the stereocomplex films were also enhanced. Moreover, the PLLA/LG-g-PDLA films have good ultraviolet resistance and excellent biocompatibility. This study provides a green approach to design advanced polylactic acid-based blends with renewable natural resources. Copyright © 2017 Elsevier B.V. All rights reserved.

Is Lactate an undervalued functional component of lactic acid bacteria-fermented food products?

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Graciela eGarrote

2015-06-01

Full Text Available Although it has been traditionally regarded as an intermediate of carbon metabolism and major component of fermented dairy products contributing to organoleptic and antimicrobial properties of food, there is evidence gathered in recent years that lactate has bioactive properties that may be responsible of broader properties of functional foods. Lactate can regulate critical functions of several key players of the immune system such as macrophages and dendritic cells, being able to modulate inflammatory activation of epithelial cells as well. Intraluminal levels of lactate derived from fermentative metabolism of lactobacilli have been shown to modulate inflammatory environment in intestinal mucosa. The molecular mechanisms responsible to these functions, including histone deacetylase dependent-modulation of gene expression and signalling through G-protein coupled receptors have started to be described. Since lactate is a major fermentation product of several bacterial families with probiotic properties, we here propose that it may contribute to some of the properties attributed to these microorganisms and in a larger view, to the properties of food products fermented by lactic acid bacteria.

Characterization of anti-listerial lactic acid bacteria isolated from Thai fermented fish products

DEFF Research Database (Denmark)

Østergaard, Anya; Embarek, Peter Karim Ben; Wedell-Neergaard, C.

1998-01-01

Thai fermented fish products were screened for lactic acid bacteria capable of inhibiting Listeria sp. (Listeria innocua). Of 4150 assumed lactic acid bacteria colonies from MRS agar plates that were screened by an agar-overlay method 58 (1.4%) were positive. Forty four of these strains were...

Lactic acid bacteria: promising supplements for enhancing the biological activities of kombucha.

Science.gov (United States)

Nguyen, Nguyen Khoi; Dong, Ngan Thi Ngoc; Nguyen, Huong Thuy; Le, Phu Hong

2015-01-01

Kombucha is sweetened black tea that is fermented by a symbiosis of bacteria and yeast embedded within a cellulose membrane. It is considered a health drink in many countries because it is a rich source of vitamins and may have other health benefits. It has previously been reported that adding lactic acid bacteria (Lactobacillus) strains to kombucha can enhance its biological functions, but in that study only lactic acid bacteria isolated from kefir grains were tested. There are many other natural sources of lactic acid bacteria. In this study, we examined the effects of lactic acid bacteria from various fermented Vietnamese food sources (pickled cabbage, kefir and kombucha) on kombucha's three main biological functions: glucuronic acid production, antibacterial activity and antioxidant ability. Glucuronic acid production was determined by high-performance liquid chromatography-mass spectrometry, antibacterial activity was assessed by the agar-well diffusion method and antioxidant ability was evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity. Four strains of food-borne pathogenic bacteria were used in our antibacterial experiments: Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028 and Bacillus cereus ATCC 11778. Our findings showed that lactic acid bacteria strains isolated from kefir are superior to those from other sources for improving glucuronic acid production and enhancing the antibacterial and antioxidant activities of kombucha. This study illustrates the potential of Lactobacillus casei and Lactobacillus plantarum isolated from kefir as biosupplements for enhancing the bioactivities of kombucha.

A study on the effect of parameters on lactic acid production from whey

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Taleghani Hamidreza Ghafouri

2016-03-01

Full Text Available In batch fermentation of whey, selection of suitable species at desired conditions such as substrate, product concentrations, temperature and inoculum size were investigated. Four Lactobacillus species and one Lactococcus species were screened for lactic acid production. Among them L. bulgaricus ATCC 11842 were selected for further studies. The optimal growth of the selected organism for variable size of inocula was examined. The results indicated that inoculum size had insignificant effect on the cell and lactic acid concentration. The effect of temperature was also studied at 32, 37, 42 and 47°C. Results showed that the concentration of cell dry weight increased with increment of temperature from 32 to 42°C. The maximum cell and lactic acid concentration was obtained at 42°C. The effect of initial substrate concentration on lactic acid production was also examined. The optimum initial lactose concentration was found to be 90 g/l.

Mass transfer behavior in lactic acid fermentation using immobilized lactobacillus delbrueckii

Energy Technology Data Exchange (ETDEWEB)

Wang, H.; Seki, M.; Furusaki, S. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

1995-08-20

We performed simulation studies on mass transfer behavior for immobilized cells in lactic acid fermentation using the mathematical model developed previously. The simulations pointed to an unusual result; that lactate ion diffuses into the bead center from outside during the batch fermentation and the startup period of the continuous fermentation, whereas free lactic acid and protons diffuse in the opposite direction. This phenomenon is caused by the addition of base to keep pH constant in the broth. Also, using an appropriate buffer to control pH in the broth can reduce the inward diffusion of lactate ion and improve the productivity of lactic acid. A singular mass transfer phenomenon is expected to take place in other production processes using immobilized cells (or enzyme), where alkali solution is added to broth to keep pH constant. 9 refs., 6 figs.

Genotypic identification and technological characterization of lactic ...

African Journals Online (AJOL)

enoh

2012-04-05

Apr 5, 2012 ... natural lactic acid bacteria (LAB) found in Kargi tulum cheese. ... remaining whey is drained by putting a weight over the ... days under anaerobic conditions at 37 or 30°C, respectively. Five ..... Part 3: Block-digestion method.

D-lactic acid interferes with the effects of platelet activating factor on bovine neutrophils.

Science.gov (United States)

Alarcón, P; Conejeros, I; Carretta, M D; Concha, C; Jara, E; Tadich, N; Hidalgo, M A; Burgos, R A

2011-11-15

D-lactic acidosis occurs in ruminants, such as cattle, with acute ruminal acidosis caused by ingestion of excessive amounts of highly fermentable carbohydrates. Affected animals show clinical signs similar to those of septic shock, as well as acute laminitis and liver abscesses. It has been proposed that the inflammatory response and susceptibility to infection could both be caused by the inhibition of phagocytic mechanisms. To determine the effects of d-lactic acid on bovine neutrophil functions, we pretreated cells with different concentrations of D-lactic acid and measured intracellular pH using 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein acetoxymethyl ester (BCECF-AM) and calcium flux using FLUO-3 AM-loaded neutrophils. Reactive oxygen species (ROS) production was measured using a luminol chemiluminescence assay, and MMP-9/gelatinase-B granule release was measured by zymography. CD11b and CD62L/l-selectin expression, changes in cell shape, superoxide anion production, phagocytosis of Escherichia coli-Texas red bioparticles, and apoptosis were all measured using flow cytometry. Our results demonstrated that D-lactic acid reduced ROS production, CD11b upregulation and MMP-9 release in bovine neutrophils treated with 100 nM platelet-activating factor (PAF). D-lactic acid induced MMP-9 release and, at higher concentrations, upregulated CD11b expression, decrease L-selectin expression, and induces late apoptosis. We concluded that D-lactic acid can interfere with neutrophil functions induced by PAF, leading to reduced innate immune responses during bacterial infections. Moreover, the increase of MMP-9 release and CD11b expression induced by 10mM D-lactic acid could promote an nonspecific neutrophil-dependent inflammatory reaction in cattle with acute ruminal acidosis. Copyright © 2011 Elsevier B.V. All rights reserved.

Analysis of Poly(Lactic-co-Glycolic Acid/Poly(Isoprene Polymeric Blend for application as biomaterial

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Douglas Ramos Marques

2013-01-01

Full Text Available The application of renewable raw materials encourages research in the biopolymers area. The Poly(Lactic-co-Glycolic Acid/Poly(Isoprene (PLGA/IR blend combines biocompatibility for application in the health field with excellent mechanical properties. The blend was obtained by solubilization of polymers in organic solvents. To investigate the polymer thermochemical properties, FTIR and DSC were applied. To investigate the composition's influence over polymer mechanical properties, tensile and hardness test were applied. To analyze the blends response in the cell environment, a stent was produced by injection molding process, and Cell Viability Test and Previous Implantability were used. The Infrared spectra show that chemical composition is related only with polymers proportion in the blend. The calorimetry shows a partial miscibility in the blend. The tensile test shows that adding Poly(Isoprene to Poly(Lactic-co-Glycolic Acid induced a relevant reduction in the Young modulus, tensile stress and tenacity of the material, which was altered from the fragile raw PLGA to a ductile material. The composition did not affect the blend hardness. The cell viability test shows that the blend has potential application as biomaterial, while the first results of implantability indicate that the polymeric stent kept its original position and caused low fibrosis.

Characterization And Identification Of Lactic Acid Bacteria From ...

African Journals Online (AJOL)

$hr3k

2013-06-05

, Pakistan. Accepted ... stands next to whole milk especially during summer. Dahi ... natural preservation. ... LAB is more varying and inconsistent as compared to ..... Interaction between probiotic lactic acid bacteria and canine.

Production of L-lactic acid from metabolically engineered strain of Enterobacter aerogenes ATCC 29007.

Science.gov (United States)

Thapa, Laxmi Prasad; Lee, Sang Jun; Park, Chulhwan; Kim, Seung Wook

2017-07-01

In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δpta) was generated by the deletion of phosphate acetyltransferase (pta) gene from the chromosome of E. aerogenes ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37°C and pH 6 for 84h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δpta) in flask fermentation using 100g/L mannitol as the carbon source was 40.05g/L as compared to that of the wild type counterpart 20.70g/L. At the end of the batch fermentation in bioreactor the production of L-lactic acid reached to 46.02g/L and yield was 0.41g/g by utilizing 112.32g/L mannitol. This is the first report regarding the production of L-lactic acid from Enterobacter species. We believe that this result may provide valuable guidelines for further engineering Enterobacter strain for the improvement of L-lactic acid production. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of different media on production of lactic acid from whey by ...

African Journals Online (AJOL)

Whey containing 50 g.l -1 lactose was fermented to lactic acid in batch process by Lactobacillus bulgaricus. The impact of 5 different media with change in volume percent of whey and nutrient was investigated at 32 ± 0.5°C. Substrate consumption and lactic acid production were determined at 0, 12, 24, 36, 48, 60 and 72 h.

Isolation and Characterization of Lactic Acid Bacteria from Inasua

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Ferymon Mahulette

2017-04-01

Full Text Available Inasua is a traditionally product of wet salt fish fermentation produced by Teon, Nila and Serua (TNS Communities in Central Maluku, Indonesia. The community made this fermented fish to anticipate the lean time when fisherman could not go to sea.  The  fish that used as inasua raw material is demersal fishes that live around coral reefs, such as Samandar fish (Siganatus guttatus, Gala-gala fish (Lutjanus sp. and Sikuda fish (Lethrinus ornatus. The objective of the research was to isolate and characterize of bacterial indigenous in  Inasua from three producers in Seram Island. The measurement of pH from inasua samples were 5.9, 5.0 and 5.8, respectively. The highest number of lactic acid bacteria was found from  Gala – gala inasua was 2,5x107 cfu/g sample. Isolation of all isolates bacteria from inasua showed that a total of 7 isolates of bacteria was obtained  from Samadar inasua, 9 isolates from  Gala-gala inasua, and 7 isolates from  Sikuda inasua.  From a total of 23 isolates, only 6 isolates had characteristic as lactic acid bacteria that were Gram  positive, negative catalase, and cocci shape. The microscopic characteristics  of the isolates are coccid in pairs or uniforms which combine to form tetrads. Carbohydrate utilization test  of selected isolate by using API 50 CHB kit indicated that 13 carbohydrates are fermented by these isolates  after incubation for 48 hours. The research  was concluded that the dominant bacteria in inasua sample  is  cocci-lactic acid bacteria. Keywords : fermented fish, inasua, lactic acid bacteria, MRSA medium

Cerebral lactic acidosis correlates with neurological impairment in MELAS.

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Kaufmann, P; Shungu, D C; Sano, M C; Jhung, S; Engelstad, K; Mitsis, E; Mao, X; Shanske, S; Hirano, M; DiMauro, S; De Vivo, D C

2004-04-27

To evaluate the role of chronic cerebral lactic acidosis in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). The authors studied 91 individuals from 34 families with MELAS and the A3243G point mutation and 15 individuals from two families with myoclonus epilepsy and ragged red fibers (MERRF) and the A8344G mutation. Subjects were divided into four groups. Paternal relatives were studied as controls (Group 1). The maternally related subjects were divided clinically into three groups: asymptomatic (no clinical evidence of neurologic disease) (Group 2), oligosymptomatic (neurologic symptoms but without the full clinical picture of MELAS or MERRF) (Group 3), and symptomatic (fulfilling MELAS or MERRF criteria) (Group 4). The authors performed a standardized neurologic examination, neuropsychological testing, MRS, and leukocyte DNA analysis in all subjects. The symptomatic and oligosymptomatic MELAS subjects had significantly higher ventricular lactate than the other groups. There was a significant correlation between degree of neuropsychological and neurologic impairment and cerebral lactic acidosis as estimated by ventricular MRS lactate levels. High levels of ventricular lactate, the brain spectroscopic signature of MELAS, are associated with more severe neurologic impairment.

Accelerated fatigue of dentin with exposure to lactic acid.

Science.gov (United States)

Do, D; Orrego, S; Majd, H; Ryou, H; Mutluay, M M; Xu, Hockin H K; Arola, D

2013-11-01

Composite restorations accumulate more biofilm than other dental materials. This increases the likelihood for the hard tissues supporting a restoration (i.e. dentin and enamel) to be exposed to acidic conditions beyond that resulting from dietary variations. In this investigation the fatigue strength and fatigue crack growth resistance of human coronal dentin were characterized within a lactic acid solution (with pH = 5) and compared to that of controls evaluated in neutral conditions (pH = 7). A comparison of the fatigue life distributions showed that the lactic acid exposure resulted in a significant reduction in the fatigue strength (p ≤ 0.001), and nearly 30% reduction in the apparent endurance limit (from 44 MPa to 32 MPa). The reduction in pH also caused a significant decrease (p ≤ 0.05) in the threshold stress intensity range required for the initiation of cyclic crack growth, and significant increase in the incremental rate of crack extension. Exposure of tooth structure to lactic acid may cause demineralization, but it also increases the likelihood of restored tooth failures via fatigue, and after short time periods. © 2013 Elsevier Ltd. All rights reserved.

Chemical Peels

Science.gov (United States)

... Back Injectable Deoxycholic Acid Injectable Hyaluronic Acid Injectable Poly-l-lactic Acid Injectable Polymethylmethacrylate + Bovine Collagen Filler ... but do not cause a great deal of pain. The gentlest peels use alpha-hydroxy, glycolic, lactic ...

Some features of transplutonium and rare earth elements extraction by HDEHP from lactic acid solutions

International Nuclear Information System (INIS)

Nikolaev, V.M.; Lebedev, V.M.; Lebedeva, L.S.

1986-01-01

The mechanisms of transplutonium (TPE) and rare earth elements (REE) extraction by HDEHP from lactic acid solutions are analysed in the literature. On the base of the known expressions and experimental data the model for TPE and REE extraction by HDEHP from lactic acid, accounting lactic acid and metal extraction as MeA 3 x3HA, MeLA 2 x2HA and MeLA 2 complexes, is suggested. The expression, permitting to estimate quantitatively the effect of TPE and REE complexing with lactic acid and the extraction of complex forms on the distribution coefficient of the extracted metal, is obtained. Comparison of calculational data with experimental ones show their good coincidence that confirms the rightness of the model accepted for extraction

Probiotic lactic acid bacteria ? the fledgling cuckoos of the gut?

OpenAIRE

Berstad, Arnold; Raa, Jan; Midtvedt, Tore; Valeur, J?rgen

2016-01-01

It is tempting to look at bacteria from our human egocentric point of view and label them as either ‘good’ or ‘bad’. However, a microbial society has its own system of government – ‘microcracy’ – and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being ‘friendly’ – th...

Probiotic lactic acid bacteria - the fledgling cuckoos of the gut?

Science.gov (United States)

Berstad, Arnold; Raa, Jan; Midtvedt, Tore; Valeur, Jørgen

2016-01-01

It is tempting to look at bacteria from our human egocentric point of view and label them as either 'good' or 'bad'. However, a microbial society has its own system of government - 'microcracy' - and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being 'friendly' - they may instead behave like fledgling cuckoos.

ASIC3: A Lactic Acid Sensor for Cardiac Pain

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D.C. Immke

2001-01-01

Full Text Available Angina, the prototypic vasoocclusive pain, is a radiating chest pain that occurs when heart muscle gets insufficient blood because of coronary artery disease. Other examples of vasoocclusive pain include the acute pain of heart attack and the intermittent pains that accompany sickle cell anemia and peripheral artery disease. All these conditions cause ischemia � insufficient oxygen delivery for local metabolic demand — and this releases lactic acid as cells switch to anaerobic metabolism. Recent discoveries demonstrate that sensory neurons innervating the heart are richly endowed with an ion channel that is opened by, and perfectly tuned for, the lactic acid released by muscle ischemia[1,2].

Effect of high pressure on mesophilic lactic fermentation streptococci

Energy Technology Data Exchange (ETDEWEB)

Reps, A; Kuzmicka, M; Wisniewska, K [Chair of Food Biotechnology, University of Warmia and Mazury, ul. Heweliusza 1, 10-724 Olsztyn (Poland)], E-mail: arnold.reps@uwm.edu.pl

2008-07-15

The research concerned the effect of high pressure on mesophilic lactic fermentation streptococci, present in two cheese-making commercial inocula produced by Christian-Hansen. Water solutions of inocula were pressurized at 50-800 MPa, at room temperature, for 30-120 min. Pressurization at 50-100 MPa slightly increased or reduced the number of lactic streptococci, depending on the inoculum and pressurization time. Pressurization at 200 MPa caused a reduction in the number of streptococci by over 99.9%, whereas the pressure of 400 MPa and above almost completely inactivated streptococci. Pressurization also reduced the dynamics of microorganism growth and acidification, to the degree depending on the pressure.

Identification of exopolysaccharides-producing lactic acid bacteria ...

African Journals Online (AJOL)

Spacer region between 16S and 23 S rRNA genes of thirteen lactic acid bacteria strains from Burkina Faso fermented milk samples were amplified by the polymerase chain reaction (PCR). Lactobacillus delbrueckii, Lactobacillus acidophilus, Lactobacillus fermentum, Streptococcus thermophilus, Pediococcus spp, ...

The proteolytic systems of lactic acid bacteria

NARCIS (Netherlands)

Kunji, Edmund R.S.; Mierau, Igor; Hagting, Anja; Poolman, Bert; Konings, Wil N.

1996-01-01

Proteolysis in dairy lactic acid bacteria has been studied in great detail by genetic, biochemical and ultrastructural methods. From these studies the picture emerges that the proteolytic systems of lactococci and lactobacilli are remarkably similar in their components and mode of action. The

Production of D- and L-Lactic Acid by Mono- and Mixed Cultures of Lactobacillus sp.

Directory of Open Access Journals (Sweden)

Antonija Trontel

2011-01-01

Full Text Available Batch cultivation of monoculture of Lactobacillus sp. and two–strain mixed culture of Lactobacillus sp. and Lactobacillus amylovorus DSM 20531T was carried out with the aim of producing L-(+- and D-(–/L-(+-lactic acid to be implemented in poly(lactic acid polymer production. Metabolic capacity of two Lactobacillus strains to ferment different carbon sources (glucose, sucrose or soluble starch during cultivation in MRS medium at 40 °C, in a laboratory-scale stirred tank bioreactor was defined. Lactobacillus sp. showed similar affinity towards mono- and disaccharide substrates, which were homofermentatively converted mostly to L-(+-lactic acid. L. amylovorus DSM 20531T has been characterized as a D/L-lactate producer and it is capable of conducting simultaneous saccharification and fermentation. Due to the interaction of Lactobacillus sp. with L. amylovorus DSM 20531T, starch was hydrolysed and fermented to the mixture of L-(+- and D-(–-lactic acid. Modified Luedeking-Piret kinetics used for the description of substrate utilization, growth of mono- and mixed cultures and production of lactic acid stereoisomers showed good agreement with experimental data.

The influence of brewers' yeast addition on lactic acid fermentation of brewers' spent grain hydrolysate by Lactobacillus rhamnosus

OpenAIRE

Pejin, Jelena; Radosavljević, Miloš; Kocić-Tanackov, Sunčica; Đukić-Vuković, Aleksandra; Mladenović, Dragana; Mojović, Ljiljana

2015-01-01

In this study brewers' spent grain (BSG) hydrolysate was produced using optimal conditions. Hydrolysates were used for lactic acid fermentation by Lactobacillus rhamnosus ATCC 7469. The aim of this study was to evaluate possibilities of the BSG hydrolysate utilization as a substrate for lactic acid fermentation as well as the effect of dry brewers' yeast (1.0, 3.0, and 5.0 %) addition in hydrolysate on lactic acid fermentation parameters (L-(+)-lactic acid and reducing sugars concentration an...

Lactic acid bacteria in the quality improvement and depreciation of wine.

Science.gov (United States)

Lonvaud-Funel, A

1999-01-01

The winemaking process includes two main steps: lactic acid bacteria are responsible for the malolactic fermentation which follows the alcoholic fermentation by yeasts. Both types of microorganisms are present on grapes and on cellar equipment. Yeasts are better adapted to growth in grape must than lactic acid bacteria, so the alcoholic fermentation starts quickly. In must, up to ten lactic acid bacteria species can be identified. They belong to the Lactobacillus, Pediococcus, Leuconostoc and Oenococcus genera. Throughout alcoholic fermentation, a natural selection occurs and finally the dominant species is O. oeni, due to interactions between yeasts and bacteria and between bacteria themselves. After bacterial growth, when the population is over 10(6) CFU/ml, malolactic transformation is the obvious change in wine composition. However, many other substrates can be metabolized. Some like remaining sugars and citric acid are always assimilated by lactic acid bacteria, thus providing them with energy and carbon. Other substrates such as some amino acids may be used following pathways restricted to strains carrying the adequate enzymes. Some strains can also produce exopolysaccharides. All these transformations greatly influence the sensory and hygienic quality of wine. Malic acid transformation is encouraged because it induces deacidification. Diacetyl produced from citric acid is also helpful to some extent. Sensory analyses show that many other reactions change the aromas and make malolactic fermentation beneficial, but they are as yet unknown. On the contrary, an excess of acetic acid, the synthesis of glucane, biogenic amines and precursors of ethylcarbamate are undesirable. Fortunately, lactic acid bacteria normally multiply in dry wines; moreover some of these activities are not widespread. Moreover, the most striking trait of wine lactic acid bacteria is their capacity to adapt to a hostile environment. The mechanisms for this are not yet completely elucidated

Production of lactic acid from corn cobs through fermentation lactobacillus delbruekii

International Nuclear Information System (INIS)

Ali, Z.; Anjum, M.; Zahoor, T.

2007-01-01

Corn cobs were used as the source of reducing sugars for conversion into lactic acid through fermentation by a local strain of Lactobacillus delbruekii, under varying parameters of time, temperature, pH and glucose concentration, The production of lactic acid significantly increased with increase in Ph, fermentation time and glucose concentration (1-5%) and was significantly high (8.40 g/1) at pH 6, while significantly low (7.67 g/1) at pH 5. (author)

Strategies for improving production performance of probiotic Pediococcus acidilactici viable cell by overcoming lactic acid inhibition.

Science.gov (United States)

Othman, Majdiah; Ariff, Arbakariya B; Wasoh, Helmi; Kapri, Mohd Rizal; Halim, Murni

2017-11-27

Lactic acid bacteria are industrially important microorganisms recognized for fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Fermentation conditions such as concentration of initial glucose in the culture, concentration of lactic acid accumulated in the culture, types of pH control strategy, types of aeration mode and different agitation speed had influenced the cultivation performance of batch fermentation of Pediococcus acidilactici. The maximum viable cell concentration obtained in constant fed-batch fermentation at a feeding rate of 0.015 L/h was 6.1 times higher with 1.6 times reduction in lactic acid accumulation compared to batch fermentation. Anion exchange resin, IRA 67 was found to have the highest selectivity towards lactic acid compared to other components studied. Fed-batch fermentation of P. acidilactici coupled with lactic acid removal system using IRA 67 resin showed 55.5 and 9.1 times of improvement in maximum viable cell concentration compared to fermentation without resin for batch and fed-batch mode respectively. The improvement of the P. acidilactici growth in the constant fed-batch fermentation indicated the use of minimal and simple process control equipment is an effective approach for reducing by-product inhibition. Further improvement in the cultivation performance of P. acidilactici in fed-bath fermentation with in situ addition of anion-exchange resin significantly helped to enhance the growth of P. acidilactici by reducing the inhibitory effect of lactic acid and thus increasing probiotic production.

Conversion of Aqueous Ammonia-Treated Corn Stover to Lactic Acid by Simultaneous Saccharification and Cofermentation

Science.gov (United States)

Zhu, Yongming; Lee, Y. Y.; Elander, Richard T.

Treatment of corn stover with aqueous ammonia removes most of the structural lignin, whereas retaining the majority of the carbohydrates in the solids. After treatment, both the cellulose and hemicellulose in corn stover become highly susceptible to enzymatic digestion. In this study, corn stover treated by aqueous ammonia was investigated as the substrate for lactic acid production by simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Spezyme-CP) and Lactobacillus pentosus American Type Culture Collection (ATCC) 8041 (Spanish Type Culture Collection [CECT]-4023) were used for hydrolysis and fermentation, respectively. In batch SSCF operation, the carbohydrates in the treated corn stover were converted to lactic acid with high yields, the maximum lactic acid yield reaching 92% of the stoichiometric maximum based on total fermentable carbohydrates (glucose, xylose, and arabinose). A small amount of acetic acid was also produced from pentoses through the phosphoketolase pathway. Among the major process variables for batch SSCF, enzyme loading and the amount of yeast extract were found to be the key factors affecting lactic acid production. Further tests on nutrients indicated that corn steep liquor could be substituted for yeast extract as a nitrogen source to achieve the same lactic acid yield. Fed-batch operation of the SSCF was beneficial in raising the concentration of lactic acid to a maximum value of 75.0 g/L.

Understanding lactic acidosis in paracetamol (acetaminophen) poisoning.

Science.gov (United States)

Shah, Anoop D; Wood, David M; Dargan, Paul I

2011-01-01

Paracetamol (acetaminophen) is one of the most commonly taken drugs in overdose in many areas of the world, and the most common cause of acute liver failure in both the UK and USA. Paracetamol poisoning can result in lactic acidosis in two different scenarios. First, early in the course of poisoning and before the onset of hepatotoxicity in patients with massive ingestion; a lactic acidosis is usually associated with coma. Experimental evidence from studies in whole animals, perfused liver slices and cell cultures has shown that the toxic metabolite of paracetamol, N-acetyl-p-benzo-quinone imine, inhibits electron transfer in the mitochondrial respiratory chain and thus inhibits aerobic respiration. This occurs only at very high concentrations of paracetamol, and precedes cellular injury by several hours. The second scenario in which lactic acidosis can occur is later in the course of paracetamol poisoning as a consequence of established liver failure. In these patients lactate is elevated primarily because of reduced hepatic clearance, but in shocked patients there may also be a contribution of peripheral anaerobic respiration because of tissue hypoperfusion. In patients admitted to a liver unit with paracetamol hepatotoxicity, the post-resuscitation arterial lactate concentration has been shown to be a strong predictor of mortality, and is included in the modified King's College criteria for consideration of liver transplantation. We would therefore recommend that post-resuscitation lactate is measured in all patients with a severe paracetamol overdose resulting in either reduced conscious level or hepatic failure. © 2010 The Authors. British Journal of Clinical Pharmacology © 2010 The British Pharmacological Society.

Production of lactic acid from hemicellulose extracts by Bacillus coagulans MXL-9.

Science.gov (United States)

Walton, Sara L; Bischoff, Kenneth M; van Heiningen, Adriaan R P; van Walsum, G Peter

2010-08-01

Bacillus coagulans MXL-9 was found capable of growing on pre-pulping hemicellulose extracts, utilizing all of the principle monosugars found in woody biomass. This organism is a moderate thermophile isolated from compost for its pentose-utilizing capabilities. It was found to have high tolerance for inhibitors such as acetic acid and sodium, which are present in pre-pulping hemicellulose extracts. Fermentation of 20 g/l xylose in the presence of 30 g/l acetic acid required a longer lag phase but overall lactic acid yield was not diminished. Similarly, fermentation of xylose in the presence of 20 g/l sodium increased the lag time but did not affect overall product yield, though 30 g/l sodium proved completely inhibitory. Fermentation of hot water-extracted Siberian larch containing 45 g/l total monosaccharides, mainly galactose and arabinose, produced 33 g/l lactic acid in 60 h and completely consumed all sugars. Small amounts of co-products were formed, including acetic acid, formic acid, and ethanol. Hemicellulose extract formed during autohydrolysis of mixed hardwoods contained mainly xylose and was converted into lactic acid with a 94% yield. Green liquor-extracted hardwood hemicellulose containing 10 g/l acetic acid and 6 g/l sodium was also completely converted into lactic acid at a 72% yield. The Bacillus coagulans MXL-9 strain was found to be well suited to production of lactic acid from lignocellulosic biomass due to its compatibility with conditions favorable to industrial enzymes and its ability to withstand inhibitors while rapidly consuming all pentose and hexose sugars of interest at high product yields.

Production of L- and D-lactic acid from waste Curcuma longa biomass through simultaneous saccharification and cofermentation.

Science.gov (United States)

Nguyen, Cuong Mai; Kim, Jin-Seog; Nguyen, Thanh Ngoc; Kim, Seul Ki; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Kim, Jin-Cheol

2013-10-01

Simultaneous saccharification and cofermentation (SSCF) of Curcuma longa waste biomass obtained after turmeric extraction to L- and D-lactic acid by Lactobacillus coryniformis and Lactobacillus paracasei, respectively, was investigated. This is a rich, starchy, agro-industrial waste with potential for use in industrial applications. After optimizing the fermentation of the biomass by adjusting nitrogen sources, enzyme compositions, nitrogen concentrations, and raw material concentrations, the SSCF process was conducted in a 7-l jar fermentor at 140 g dried material/L. The maximum lactic acid concentration, average productivity, reducing sugar conversion and lactic acid yield were 97.13 g/L, 2.7 g/L/h, 95.99% and 69.38 g/100 g dried material for L-lactic acid production, respectively and 91.61 g/L, 2.08 g/L/h, 90.53% and 65.43 g/100 g dried material for D-lactic acid production, respectively. The simple and efficient process described in this study could be utilized by C. longa residue-based lactic acid industries without requiring the alteration of plant equipment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of Pyruvate Decarboxylase Knockout on Product Distribution Using Pichia pastoris (Komagataella phaffii) Engineered for Lactic Acid Production.

Science.gov (United States)

Melo, Nadiele T M; Mulder, Kelly C L; Nicola, André Moraes; Carvalho, Lucas S; Menino, Gisele S; Mulinari, Eduardo; Parachin, Nádia S

2018-02-16

Lactic acid is the monomer unit of the bioplastic poly-lactic acid (PLA). One candidate organism for lactic acid production is Pichia pastoris , a yeast widely used for heterologous protein production. Nevertheless, this yeast has a poor fermentative capability that can be modulated by controlling oxygen levels. In a previous study, lactate dehydrogenase (LDH) activity was introduced into P. pastoris, enabling this yeast to produce lactic acid. The present study aimed to increase the flow of pyruvate towards the production of lactic acid in P. pastoris . To this end, a strain designated GLp was constructed by inserting the bovine lactic acid dehydrogenase gene (LDHb) concomitantly with the interruption of the gene encoding pyruvate decarboxylase (PDC). Aerobic fermentation, followed by micro-aerophilic culture two-phase fermentations, showed that the GLp strain achieved a lactic acid yield of 0.65 g/g. The distribution of fermentation products demonstrated that the acetate titer was reduced by 20% in the GLp strain with a concomitant increase in arabitol production: arabitol increased from 0.025 g/g to 0.174 g/g when compared to the GS115 strain. Taken together, the results show a significant potential for P. pastoris in producing lactic acid. Moreover, for the first time, physiological data regarding co-product formation have indicated the redox balance limitations of this yeast.

Concurrent Lactic and Volatile Fatty Acid Analysis of Microbial Fermentation Samples by Gas Chromatography with Heat Pre-treatment.

Science.gov (United States)

Darwin; WipaCharles; Cord-Ruwisch, Ralf

2018-01-01

Organic acid analysis of fermentation samples can be readily achieved by gas chromatography (GC), which detects volatile organic acids. However, lactic acid, a key fermentation acid is non-volatile and can hence not be quantified by regular GC analysis. However the addition of periodic acid to organic acid samples has been shown to enable lactic acid analysis by GC, as periodic acid oxidizes lactic acid to the volatile acetaldehyde. Direct GC injection of lactic acid standards and periodic acid generated inconsistent and irreproducible peaks, possibly due to incomplete lactic acid oxidation to acetaldehyde. The described method is developed to improve lactic acid analysis by GC by using a heat treated derivatization pre-treatment, such that it becomes independent of the retention time and temperature selection of the GC injector. Samples containing lactic acid were amended by periodic acid and heated in a sealed test tube at 100°C for at least 45 min before injecting it to the GC. Reproducible and consistent peaks of acetaldehyde were obtained. Simultaneous determination of lactic acid, acetone, ethanol, butanol, volatile fatty acids could also be accomplished by applying this GC method, enabling precise and convenient organic acid analysis of biological samples such as anaerobic digestion and fermentation processes. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Fundamentals of poly(lactic acid) microstructure, crystallization behavior, and properties

Science.gov (United States)

Kang, Shuhui

Poly(lactic acid) is an environmentally-benign biodegradable and sustainable thermoplastic material, which has found broad applications as food packaging films and as non-woven fibers. The crystallization and deformation mechanisms of the polymer are largely determined by the distribution of conformation and configuration. Knowledge of these mechanisms is needed to understand the mechanical and thermal properties on which processing conditions mainly depend. In conjunction with laser light scattering, Raman spectroscopy and normal coordinate analysis are used in this thesis to elucidate these properties. Vibrational spectroscopic theory, Flory's rotational isomeric state (RIS) theory, Gaussian chain statistics and statistical mechanics are used to relate experimental data to molecular chain structure. A refined RIS model is proposed, chain rigidity recalculated and chain statistics discussed. A Raman spectroscopic characterization method for crystalline and amorphous phase orientation has been developed. A shrinkage model is also proposed to interpret the dimensional stability for fibers and uni- or biaxially stretched films. A study of stereocomplexation formed by poly(l-lactic acid) and poly(d-lactic acid) is also presented.

Correlation between working positions and lactic acid levels with musculoskeletal complaints among dentists

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Fiory Dioptis Putriwijaya

2016-12-01

Full Text Available Background: Musculoskeletal complaints have been common for dentists since their body is unknowingly often in inappropriate positions when caring for patients. For example, they bend towards patients, suddenly move, and then rotate from one side to another. The repetitive movements are done in long term. High activities and sufficient recovery time can cause a buildup of lactic acid in their blood leading to obstruction of the energy intake from the aerobic system in their muscle cells, resulting in fatigue. As a result, such conditions trigger decreased muscle performances. Purpose: This study aimed to determine the correlation between working positions and lactic acid levels with the risk of musculoskeletal disorders among dentists at Public Health Centers in Surabaya. Method: This research was an analytical observational research using cross sectional approach. Sampling technique used in this research was cluster random sampling with nineteen samples. To evaluate the working positions of those samples, a rapid entire body assessment (REBA method was used. Meanwhile, to observe the musculoskeletal disorders of those samples, a Nordic body map was used. Data obtained then were analyzed using Pearson correlation test with a significance level (p<0.05. Result: Results of data analysis using the Pearson correlation test showed that the significance value obtained was 0.036. It indicates that there was a correlation between the working positions and the lactic acid levels with the musculoskeletal disorders in those dentists. The results of the Pearson correlation test also revealed that there was a correlation between the working positions and the lactic acid levels among those dentists with a significance value of 0.025. Conclusion: It may be concluded that the wrong body positions during working can increase lactic acid level in the body of dentists. The increased level of lactic acid then can affect their muscles, leading to the high risk of

Influence of different sterilization processes on the properties of commercial poly(lactic acid)

Energy Technology Data Exchange (ETDEWEB)

Savaris, M.; Santos, V. dos, E-mail: vsantos2@ucs.br; Brandalise, R.N.

2016-12-01

This study aims at analyzing the modifications in the morphological, physical, chemical and thermal properties of commercial poly(lactic acid) (PLA) films after exposure to five different sterilization processes. Films were obtained by compression molding, hygienized and sterilized by ethylene oxide (SEtO), hydrogen peroxide plasma (SH{sub 2}O{sub 2}), saturated steam (SSS), electron beam radiation (SEB) and gamma radiation (SGR). The samples of PLA{sub SEtO}, PLA{sub SH2O2}, PLA{sub SEB} and PLA{sub SGR} exhibited thermal and physical changes after being submitted to sterilization processes. PLA{sub SSS} showed morphological, chemical, thermal and physical changes. It is concluded that processes by SEtO, SH{sub 2}O{sub 2}, SEB and EGR can be applied for the sterilization of PLA films and the SSS process is not recommended in view of the data obtained and test conditions reported in this study for PLA films. - Highlights: • PLA was subjected to five different sterilization process. • All sterilization processes do not changed the hydrophilicity of PLA. • Morphological, chemical, physical and thermal changes were observed for the PLA{sub SSS}. • The sterilization by saturated steam is not recommended to sterilize PLA.

SLUG FLOW CAPILLARY MICROREACTORS FOR LACTIC ACID EXTRACTION: EXPERIMENTAL STUDY AND MASS TRANSFER MODELLING

NARCIS (Netherlands)

Susanti, Susanti; Winkelman, Jozef; Schuur, Boelo; Heeres, Hero; Yue, Jun

2015-01-01

Lactic acid is an important commercial product and has been widely used for manufacturing biodegradable polymer. Current method of lactic acid isolation from fermentation broths is energy intensive and leads to the formation of large amounts of salts. Reactive liquid-liquid extraction has been

Antimicrobial Activity – The Most Important Property of Probiotic and Starter Lactic Acid Bacteria

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Blaženka Kos

2010-01-01

Full Text Available The antimicrobial activity of industrially important lactic acid bacteria as starter cultures and probiotic bacteria is the main subject of this review. This activity has been attributed to the production of metabolites such as organic acids (lactic and acetic acid, hydrogen peroxide, ethanol, diacetyl, acetaldehyde, acetoine, carbon dioxide, reuterin, reutericyclin and bacteriocins. The potential of using bacteriocins of lactic acid bacteria, primarily used as biopreservatives, represents a perspective, alternative antimicrobial strategy for continuously increasing problem with antibiotic resistance. Another strategy in resolving this problem is an application of probiotics for different gastrointestinal and urogenital infection therapies.

Phenotypic and genotypic characterization of lactic acid bacteria ...

African Journals Online (AJOL)

... of lactic acid bacteria isolated from Azerbaijani traditional dairy products. ... yogurts were produced from bovine's milk and the Ganja yogurt from buffalo's milk. ... It was determined using biochemical tests and molecular methods that four ...

Reactive extraction of lactic acid using alamine

NARCIS (Netherlands)

Wasewar, Kailas L.; Heesink, Albertus B.M.; Versteeg, Geert; Pangarkar, Vishwas G.

2002-01-01

Lactic acid is an important commercial product and extracting it out of aqueous solution is a growing requirement in fermentation based industries and recovery from waste streams. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid–amine (solvent)

New Poly(lactic acid Active Packaging Composite Films Incorporated with Fungal Melanin

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Łukasz Łopusiewicz

2018-04-01

Full Text Available In this work, fungal melanin was used for the first time to prepare poly(lactic acid-based composites. The films of various melanin concentrations (0.025%, 0.05% and 0.2% w/w were prepared using an extrusion method. The mechanical, antioxidant, antimicrobial, water vapor and UV-Vis barrier properties, as well as available polyphenolics on the surface, were studied. FT-IR and Raman spectroscopy studies were carried out to analyze the chemical composition of the resulting films. The hydrophobicity, color response, thermal, optical properties, and opacity values were also determined. The results of this study show that the addition of fungal melanin to poly(lactic acid (PLA as a modifier influenced mechanical and water vapor barrier properties depending on melanin concentration. In low concentration, melanin enhanced the mechanical and barrier properties of the modified films, but in larger amounts, the properties were decreased. The UV-Vis barrier properties of PLA/melanin composites were marginally improved. Differential Scanning Calorimetry (DSC analysis indicated that crystallinity of PLA increased by the addition of melanin, but this did not affect the thermal stability of the films. Modified PLA/melanin films showed good antioxidant activity and were active against Enterococcus faecalis, Pseudomonas aeruginosa and Pseudomonas putida. The addition of melanin caused changes in color values, decreasing lightness and increasing the redness and yellowness of films. Based on the results of this study, fungal melanin has good potential to be exploited as a value-added modifier that can improve the overall properties of PLA.

Lactic acid fermentation of human urine to improve its fertilizing value and reduce odour emissions.

Science.gov (United States)

Andreev, N; Ronteltap, M; Boincean, B; Wernli, M; Zubcov, E; Bagrin, N; Borodin, N; Lens, P N L

2017-08-01

During storage of urine, urea is biologically decomposed to ammonia, which can be lost through volatilization and in turn causes significant unpleasant smell. In response, lactic acid fermentation of urine is a cost-effective technique to decrease nitrogen volatilization and reduce odour emissions. Fresh urine (pH = 5.2-5.3 and NH 4 + -N = 1.2-1.3 g L -1 ) was lacto-fermented for 36 days in closed glass jars with a lactic acid bacterial inoculum from sauerkraut juice and compared to untreated, stored urine. In the lacto-fermented urine, the pH was reduced to 3.8-4.7 and the ammonium content by 22-30%, while the pH of the untreated urine rose to 6.1 and its ammonium content increased by 32% due to urea hydrolysis. The concentration of lactic acid bacteria in lacto-fermented urine was 7.3 CFU ml -1 , suggesting that urine is a suitable growth medium for lactic acid bacteria. The odour of the stored urine was subjectively perceived by four people to be twice as strong as that of lacto-fermented samples. Lacto-fermented urine induced increased radish germination compared to stored urine (74-86% versus 2-31%). Adding a lactic acid bacterial inoculum to one week old urine in the storage tanks in a urine-diverting dry toilet reduced the pH from 8.9 to 7.7 after one month, while the ammonium content increased by 35%, probably due to the high initial pH of the urine. Given that the hydrolyzed stale urine has a high buffering capacity, the lactic acid bacterial inoculum should be added to the urine storage tank of a UDDT before urine starts to accumulate there to increase the efficiency of the lactic acid fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis of 1- and 3-11C-labelled L-lactic acid using multi-enzyme catalysis

International Nuclear Information System (INIS)

Bjurling, P.; Laangstroem, B.

1990-01-01

The synthesis of 1- and 3- 11 C-labelled L-lactic acid from the corresponding racemic 1- or 3- 11 C-labelled alanine using a multi-enzymatic reaction route, is presented. DL-[1- 11 C]Alanine was synthesised by reacting sodium 1-hydroxy-ethyl sulfite with hydrogen [ 11 C]cyanide, obtained from [ 11 C]carbon dioxide, and ammonia followed by acid hydrolysis. DL-[3- 11 C]-Alanine was synthesised by a methylation of a glycine derivative, N-(diphenylmethylene)-glycine tert-butyl ester, with [ 11 C]methyl iodide, obtained from [ 11 C]carbon dioxide, and subsequent hydrolysis. The racemic 1- or 3- 11 C-labelled alanine was then converted to pyruvic acid, by D-amino acid oxidase/catalase and glutamic-pyruvic transaminase, which was directly reduced to L-lactic acid by L-lactic dehydrogenase in a one-pot procedure. The total synthesis time was 40 minutes, counted from release of [ 11 C]carbon dioxide. The decay corrected radiochemical yields were ca. 80% for L-[1- 11 C]lactic acid, based on hydrogen cyanide, and ca. 60% for L-[3- 11 C]lactic acid, based on carbon dioxide. The radiochemical purities were higher than 99% analysed by HPLC. (author)

Degradation of Poly (lactic acid under Simulated Landfill Conditions

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Chomnutcha Boonmee

2017-03-01

Full Text Available In this study, the physical and chemical properties change of poly(lactic acid after burying in the mixture of soil and sludge under thermophilic (61 °C oxygen limited conditions were investigated using various analytical techniques. The environmental factors under these setting conditions and microbial activities accelerated the degradation process of PLA. Under tested conditions, PLA loss their weight about 90% at the burying time of 90 days. During the degradation process, PLA samples were continuously broken to small fragile fragments and showed the size less than 1 mm at the end of degradation test. Change of the surface morphology change was revealed by scanning electron microscopy (SEM. Many pores, cracks and irregular roughness were presented on the PLA surface. Thermal decomposition was decreased from 387.8 to 289.2 °C. The percentage of carbon content in molecular structure decreased from 49.46% to 45.42%. In addition, the Fourier transformed infrared spectroscopy (FTIR revealed the change of ester bonds. This study can be used for developing PLA waste management process.

Optimization of β-galactosidase production from lactic acid bacteria

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Carević Milica

2015-01-01

Full Text Available β-galactosidase, commonly known as lactase, represents commercially important enzyme that is prevalently used for lactose hydrolysis in milk and whey. To the date, it has been isolated from various sources. In this study different strains of lactic acid bacteria were assessed for their β-galactosidase productivity, and Lactobacillus acidophilus ATCC 4356 resulted with the highest production potential. Thereafter, optimal conditions for accomplishing high yields of β-galactosidase activity were determined. Maximal specific activity (1.01 IU mL-1 was accomplished after 2 days shake flask culture fermentation (150 rpm at 37ºC, with modified Man Rogosa Sharpe culture broth using lactose (2.5% as sole carbon source. Finally, in order to intensify release of intracellular β-galactosidase different mechanical and chemical methods were conducted. Nevertheless, vortexing with quartz sand (150 μm as abrasive was proven to be the most efficient method of cell disruption. The optimum temperature of obtained β-galactosidase was 45°C and the optimum range pH 6.5-7.5.

Lactic acid alleviates stress: good for female genital tract homeostasis, bad for protection against malignancy.

Science.gov (United States)

Witkin, Steven S

2018-05-01

Women are unique from all other mammals in that lactic acid is present at high levels in the vagina during their reproductive years. This dominance may have evolved in response to the unique human lifestyle and a need to optimally protect pregnant women and their fetuses from endogenous and exogenous insults. Lactic acid in the female genital tract inactivates potentially pathogenic bacteria and viruses, maximizes survival of vaginal epithelial cells, and inhibits inflammation that may be damaging to the developing fetus and maintenance of the pregnancy. In an analogous manner, lactic acid production facilitates survival of malignantly transformed cells, inhibits activation of immune cells, and prevents the release of pro-inflammatory mediators in response to tumor-specific antigens. Thus, the same stress-reducing properties of lactic acid that promote lower genital tract health facilitate malignant transformation and progression.

Culture-independent analysis of lactic acid bacteria diversity associated with mezcal fermentation.

Science.gov (United States)

Narváez-Zapata, J A; Rojas-Herrera, R A; Rodríguez-Luna, I C; Larralde-Corona, C P

2010-11-01

Mezcal is an alcoholic beverage obtained from the distillation of fermented juices of cooked Agave spp. plant stalks (agave must), and each region in Mexico with denomination of origin uses defined Agave species to prepare mezcal with unique organoleptic characteristics. During fermentation to produce mezcal in the state of Tamaulipas, not only alcohol-producing yeasts are involved, but also a lactic acid bacterial community that has not been characterized yet. In order to address this lack of knowledge on this traditional Mexican beverage, we performed a DGGE-16S rRNA analysis of the lactic acid bacterial diversity and metabolite accumulation during the fermentation of a typical agave must that is rustically produced in San Carlos County (Tamaulipas, Mexico). The analysis of metabolite production indicated a short but important malolactic fermentation stage not previously described for mezcal. The denaturing gradient gel electrophoresis (DGGE) analysis of the 16S rRNA genes showed a distinctive lactic acid bacterial community composed mainly of Pediococcus parvulus, Lactobacillus brevis, Lactobacillus composti, Lactobacillus parabuchneri, and Lactobacillus plantarum. Some atypical genera such as Weissella and Bacillus were also found in the residual must. Our results suggest that the lactic acid bacteria could strongly be implicated in the organoleptic attributes of this traditional Mexican distilled beverage.

Kinetics of free radical decay reactions in lactic acid homo and copolymers irradiated to sterilization dose

International Nuclear Information System (INIS)

Kantoglu, O.; Ozbey, T.; Gueven, O.

1995-01-01

The kinetics of free radical decay reactions of poly(L-Lactic acid), poly(DL-Lactic acid) and random copolymer of lactic and glycolic acid have been investigated for decays taking place in air and in vacuum. The change in ESR lines of γ-irradiated polymers have been followed over a long time period. The decay has been found to follow neither simple first-order nor second-order kinetics. Various kinetic approaches including composite first or second-order mechanisms and diffusion-controlled first or second-order equations were determined to be also unsatisfactory. The decay of radicals in bulk irradiated lactic acid homo and copolymers was found to be best described when the second-order non-classical equation with time dependent rate constant approach was used. (Author)

Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

Science.gov (United States)

Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun

2015-01-01

Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research. PMID:26068451

Effects of levan-type fructan on growth performance, nutrient digestibility, diarrhoea scores, faecal shedding of total lactic acid bacteria and coliform bacteria, and faecal gas emission in weaning pigs.

Science.gov (United States)

Lei, Xin Jian; Kim, Yong Min; Park, Jae Hong; Baek, Dong Heon; Nyachoti, Charles Martin; Kim, In Ho

2018-03-01

The use of antibiotics as growth promoters in feed has been fully or partially banned in several countries. The objective of this study was to evaluate effects of levan-type fructan on growth performance, nutrient digestibility, faecal shedding of lactic acid bacteria and coliform bacteria, diarrhoea scores, and faecal gas emission in weaning pigs. A total of 144 weaning pigs [(Yorkshire × Landrace) × Duroc] were randomly allocated to four diets: corn-soybean meal-based diets supplemented with 0, 0.1, 0.5, or 1.0 g kg -1 levan-type fructan during this 42-day experiment. During days 0 to 21 and 0 to 42, average daily gain and average daily feed intake were linearly increased (P bacteria counts were linearly increased (P = 0.001). The results indicate that dietary supplementation with increasing levan-type fructan enhanced growth performance, improved nutrient digestibility, and increased faecal lactic acid bacteria counts in weaning pigs linearly. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Ammonia oxidation at high pressure and intermediate temperatures

DEFF Research Database (Denmark)

Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt

2016-01-01

were interpreted in terms of a detailed chemical kinetic model. The rate constant for the reaction of the important intermediate H2NO with O2 was determined from ab initio calculations to be 2.3 × 102 T2.994 exp (−9510 K/T) cm3 mol−1 s−1. The agreement between experimental results and model work...

Lactic acidosis occurrence during exercises in the smoke chamber in a 53-year-old firefighter with no significant medical history

Directory of Open Access Journals (Sweden)

Agata Bronisz

2014-04-01

Full Text Available Lactic acidosis is a form of metabolic acidosis with a high anion gap, reduced rate of arterial blood pH under 7.35 mmol/l, and lactic acid concentration over 7 mmol/l. In the literature we can find some descriptions of the cases of lactic acidosis in patients with severe systemic diseases (cancer, acquired immunodeficiency syndrome, sepsis, diabetes with cardiovascular disease and after organ transplantations. We present the case of lactic acidosis in a patient with no chronic disease - a firefighter in whom lactic acidosis has developed during standard exercises in the smoke chamber.

The effect of citrulline and arginine supplementation on lactic acidemia in MELAS syndrome☆

Science.gov (United States)

El-Hattab, Ayman W.; Emrick, Lisa T.; Williamson, Kaitlin C.; Craigen, William J.; Scaglia, Fernando

2013-01-01

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a mitochondrial disorder in which nitric oxide (NO) deficiency may play a role in the pathogenesis of several complications including stroke-like episodes and lactic acidosis. Supplementing the NO precursors arginine and citrulline restores NO production in MELAS syndrome. In this study we evaluated the effect of arginine or citrulline on lactic acidemia in adults with MELAS syndrome. Plasma lactate decreased significantly after citrulline supplementation, whereas the effect of arginine supplementation did not reach statistical significance. These results support the potential therapeutic utility of arginine and citrulline in MELAS syndrome and suggest that citrulline supplementation may be more efficacious. However, therapeutic efficacy of these compounds should be further evaluated in clinical trials. PMID:25411654

The effect of citrulline and arginine supplementation on lactic acidemia in MELAS syndrome.

Science.gov (United States)

El-Hattab, Ayman W; Emrick, Lisa T; Williamson, Kaitlin C; Craigen, William J; Scaglia, Fernando

2013-12-01

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a mitochondrial disorder in which nitric oxide (NO) deficiency may play a role in the pathogenesis of several complications including stroke-like episodes and lactic acidosis. Supplementing the NO precursors arginine and citrulline restores NO production in MELAS syndrome. In this study we evaluated the effect of arginine or citrulline on lactic acidemia in adults with MELAS syndrome. Plasma lactate decreased significantly after citrulline supplementation, whereas the effect of arginine supplementation did not reach statistical significance. These results support the potential therapeutic utility of arginine and citrulline in MELAS syndrome and suggest that citrulline supplementation may be more efficacious. However, therapeutic efficacy of these compounds should be further evaluated in clinical trials.

Modification of azo dyes by lactic acid bacteria.

Science.gov (United States)

Pérez-Díaz, I M; McFeeters, R F

2009-08-01

The ability of Lactobacillus casei and Lactobacillus paracasei to modify the azo dye, tartrazine, was recently documented as the result of the investigation on red coloured spoilage in acidified cucumbers. Fourteen other lactic acid bacteria (LAB) were screened for their capability to modify the food colouring tartrazine and other azo dyes of relevance for the textile industry. Most LAB modified tartrazine under anaerobic conditions, but not under aerobic conditions in modified chemically defined media. Microbial growth was not affected by the presence of the azo dyes in the culture medium. The product of the tartrazine modification by LAB was identified as a molecule 111 daltons larger than its precursor by liquid chromatography-mass spectrometry. This product had a purple colour under aerobic conditions and was colourless under anaerobic conditions. It absorbed light at 361 and 553 nm. LAB are capable of anabolizing azo dyes only under anaerobic conditions. IMPACT AND SIGNIFICANCE OF THE STUDY: Although micro-organisms capable of reducing the azo bond on multiple dyes have been known for decades, this is the first report of anabolism of azo dyes by food related micro-organisms, such as LAB.

original article antimicrobial susceptibility pattern of lactic acid

African Journals Online (AJOL)

User

All the 57 tested lactic acid bacteria isolates were sensitive to Pencillin G (Pen, 10units), and ... resistance genes for Penicillin G and Erythromycin as indicated by the sensitivity of isolates. .... Antibiotic Susceptibility Test: The LAB isolates were ...

Effect of lactic acid suppositories compared with oral metronidazole and placebo in bacterial vaginosis: a randomised clinical trial.

Science.gov (United States)

Boeke, A J; Dekker, J H; van Eijk, J T; Kostense, P J; Bezemer, P D

1993-01-01

OBJECTIVE--To compare the effect of lactic acid locally, metronidazole orally and placebo in women with bacterial vaginosis. DESIGN--Randomised clinical trial. SETTING--30 general practices in the Netherlands. PATIENTS--125 women consulting the general practitioner for symptomatic bacterial vaginosis. MAIN OUTCOME MEASURES--Duration of subjective symptoms, recurrence of symptoms, clinically diagnosed cure, adverse events. RESULTS--Survival analysis showed a significantly faster disappearance of symptoms in the metronidazole category compared with both lactic acid and placebo (p = 0.0005 metronidazole v placebo, p = 0.0002 metronidazole v lactic acid p = 0.6521 lactic acid v placebo [The stratified Mantel Cox test]). The median duration until absence of symptoms was 21 days for metronidazole and 80 days for placebo. Disappearance of symptoms did not occur in 50% of the lactic acid group in 90 days. Recurrence rates of symptoms were similar over the treatment categories (p = 0.13 metronidazole v placebo and p = 0.12 lactic acid v placebo). After 2 weeks cure rates (cure defined as less than three of four clinical criteria present) were 83%, 49% and 47% for metronidazole, lactic acid and placebo category respectively. At that time cure rates (cure defined as none of three clinical criteria present) were 10%, 0% and 3%. After four weeks and three months these figures were: 55%, 20%, 20% and 64%, 28%, 28%. No differences in adverse events were found between the three interventions. CONCLUSIONS--Lactic acid suppositories are ineffective, metronidazole capsules are effective on signs and symptoms in bacterial vaginosis. A considerable proportion of the patients recover without active medication. PMID:8244360

Inhaled β-agonist therapy and respiratory muscle fatigue as under-recognised causes of lactic acidosis.

Science.gov (United States)

Lau, Emily; Mazer, Jeffrey; Carino, Gerardo

2013-10-14

A 49-year-old man with chronic obstructive pulmonary disease (COPD) presented with significant tachypnoea, fevers, productive cough and increased work of breathing for the previous 4 days. Laboratory data showed elevated lactate of 3.2 mEq/L. Continuous inhaled ipratropium and albuterol nebuliser treatments were administered. Lactate levels increased to 5.5 and 3.9 mEq/L, at 6 and 12 h, respectively. No infectious source was found and the lactic acidosis cleared as the patient improved. The lactic acidosis was determined to be secondary to respiratory muscle fatigue and inhaled β-agonist therapy, two under-recognised causes of lactic acidosis in patients presenting with respiratory distress. Lactic acidosis is commonly used as a clinical marker for sepsis and shock, but in the absence of tissue hypoperfusion and severe hypoxia, alternative aetiologies for elevated levels should be sought to avoid unnecessary and potentially harmful medical interventions.

Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

Directory of Open Access Journals (Sweden)

Yanhua Cui

2015-06-01

Full Text Available Plasmids are widely distributed in different sources of lactic acid bacteria (LAB as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research.

Dynamic modeling of lactic acid fermentation metabolism with Lactococcus lactis.

Science.gov (United States)

Oh, Euhlim; Lu, Mingshou; Park, Changhun; Park, Changhun; Oh, Han Bin; Lee, Sang Yup; Lee, Jinwon

2011-02-01

A dynamic model of lactic acid fermentation using Lactococcus lactis was constructed, and a metabolic flux analysis (MFA) and metabolic control analysis (MCA) were performed to reveal an intensive metabolic understanding of lactic acid bacteria (LAB). The parameter estimation was conducted with COPASI software to construct a more accurate metabolic model. The experimental data used in the parameter estimation were obtained from an LC-MS/ MS analysis and time-course simulation study. The MFA results were a reasonable explanation of the experimental data. Through the parameter estimation, the metabolic system of lactic acid bacteria can be thoroughly understood through comparisons with the original parameters. The coefficients derived from the MCA indicated that the reaction rate of L-lactate dehydrogenase was activated by fructose 1,6-bisphosphate and pyruvate, and pyruvate appeared to be a stronger activator of L-lactate dehydrogenase than fructose 1,6-bisphosphate. Additionally, pyruvate acted as an inhibitor to pyruvate kinase and the phosphotransferase system. Glucose 6-phosphate and phosphoenolpyruvate showed activation effects on pyruvate kinase. Hexose transporter was the strongest effector on the flux through L-lactate dehydrogenase. The concentration control coefficient (CCC) showed similar results to the flux control coefficient (FCC).

Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn

Science.gov (United States)

Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu

2017-10-01

A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.

Mitochondrial encephalopathy with lactic acidosis and stroke-like ...

African Journals Online (AJOL)

Laila Selim

2013-04-12

Apr 12, 2013 ... heteroplasmic A3243G mutation was detected in the blood of the patient and his mother. .... mitochondrial defects, such as lactic acidosis or Ragged Red ..... [48] Pulkes T, Eunson L, Patterson V, Siddiqui A, Wood NW, Nelson.

Controlled overproduction of proteins by lactic acid bacteria

NARCIS (Netherlands)

Kuipers, Oscar P.; Ruyter, Pascalle G.G.A. de; Kleerebezem, Michiel; Vos, Willem M. de

1997-01-01

Lactic acid bacteria are widely used in industrial food fermentations, contributing to flavour, texture and preservation of the fermented products. Here we describe recent advances in the development of controlled gene expression systems, which allow the regulated overproduction of any desirable

A comparative study on experimental and theoretical ESR spectra of lactic acid polymers irradiated by gamma rays

International Nuclear Information System (INIS)

Kantoglu, Oe.; Oezbey, T.; Gueven, O.

1998-01-01

Homo polymers of L-Lactic acid (LLA) and D,L-Lactic acid (DLLA), being biocompatible and absorbable in body iluids have recently found wide applications in the preparation of surgical sutures, controlled drug delivery systems, burn wound coverings etc. For sometime these polymers have also been prepared in the form of plates and screws for mandibular fracture fixation, tissue implants. Their chemical sensitivities against relatively high temperatures and hydrolysis with water make them unsuitable for conventional sterilization techniques like hot water vapor and ethylene oxide. Sterilization of the devices made of these polymers is therefore possible by gamma ray irradiation. This has initiated a number of research works in order to better understand the effects of ionizing radiation on this polymer. The aim of this study is to determine the possible radical types, their location on macromolecular structure and the reasons for peak shifts in the experimental and theoretical ESR spectra. Polymer samples were irradiated in air and in vacuum (10□□ torr) to 25 kGy sterilization dose at the dose rate 0.59 kGy/h and at room temperature by 60 Co γ-irradiator. Despite being chemically the same radical type, some differences were observed in the splitting of peaks of PLLA and PDLLA samples. These differences were determined and compared by means of fitting studies. Firstly, PLLA was characterized and its g and hyperfine splitting values were found as 2.0032±0.0002 and 20.37±0.2. In the characterization study of PDLLA, it was found that one of the nearest two radicals was on the upper and the other one was on the lower plane of PDLLA chain. (author)

Poly(Lactic Acid) Based Flexible Films

OpenAIRE

Fathilah binti Ali; Jamarosliza Jamaluddin; Arun Kumar Upadhyay

2014-01-01

Poly(lactic acid) (PLA) is a biodegradable polymer which has good mechanical properties, however, its brittleness limits its usage especially in packaging materials. Therefore, in this work, PLA based polyurethane films were prepared by synthesizing with different types of isocyanates; methylene diisocyanate (MDI) and hexamethylene diisocyanates (HDI). For this purpose, PLA based polyurethane must have good strength and flexibility. Therefore, polycaprolactone which has b...

Open fermentative production of L-lactic acid with high optical purity by thermophilic Bacillus coagulans using excess sludge as nutrient.

Science.gov (United States)

Ma, Kedong; Maeda, Toshinari; You, Huiyan; Shirai, Yoshihito

2014-01-01

The development of a low-cost polymer-grade L-lactic acid production process was achieved in this study. Excess sludge hydrolyzate (ESH) was chosen as nutrient source for the objective of reducing nutrient cost in lactic acid production. 1% of ESH had high performance in lactic acid production relative to 2g/l yeast extract (YE) while the production cost of ESH was much lower than that of YE, indicating ESH was a promising substitute of YE. By employing a thermophilic strain of Bacillus coagulans (NBRC 12583), non-sterilized batch and repeated batch L-lactic acid fermentation was successfully performed, and the optical purity of L-lactic acid accumulated was more than 99%. Moreover, the factors associated with cell growth and lactic acid fermentation was investigated through a two-stage lactic acid production strategy. Oxygen played an important role in cell growth, and the optimal condition for cell growth and fermentation was pH 7.0 and 50°C. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phenotypic and genotypic characterization of lactic acid bacteria isolated from raw goat milk and effect of farming practices on the dominant species of lactic acid bacteria.

Science.gov (United States)

Tormo, Hélène; Ali Haimoud Lekhal, Djamila; Roques, C

2015-10-01

Lactic acid bacteria, in particular Lactococcus lactis, play a decisive role in the cheese making process and more particularly in lactic cheeses which are primarily produced on goat dairy farms. The objective of this study was therefore to identify the main lactic acid bacteria found in raw goats' milk from three different regions in France and evaluate if certain farming practices have an effect on the distribution of species of lactic acid bacteria in the various milk samples. Identification at genus or species level was carried out using phenotypic tests and genotypic methods including repetitive element REP-PCR, species-specific PCR and 16S rRNA gene sequencing. The distribution of the main bacterial species in the milk samples varied depending on farms and their characteristics. Out of the 146 strains identified, L. lactis was the dominant species (60% of strains), followed by Enterococcus (38%) of which Enterococcus faecalis and Enterococcus faecium. Within the species L. lactis, L. lactis subsp lactis was detected more frequently than L. lactis subsp cremoris (74% vs. 26%). The predominance of L. lactis subsp cremoris was linked to geographical area studied. It appears that the animals' environment plays a role in the balance between the dominance of L. lactis and enterococci in raw goats' milk. The separation between the milking parlor and the goat shed (vs no separation) and only straw in the bedding (vs straw and hay) seems to promote L. lactis in the milk (vs enterococci). Copyright © 2015 Elsevier B.V. All rights reserved.

Antimicrobial activities of lactic acid bacteria isolated from akamu ...

African Journals Online (AJOL)

The partially purified inhibitory compounds were screened by agar spot assay method for antagonistic ... The partially purified compounds exhibited strong activity against ... Keywords: Bacteriocins, lactic acid bacteria (LAB), target organisms, ...

Characterization of Lactic Acid Bacteria (LAB) isolated from Indonesian shrimp paste (terasi)

Science.gov (United States)

Amalia, U.; Sumardianto; Agustini, T. W.

2018-02-01

Shrimp paste was one of fermented products, popular as a taste enhancer in many dishes. The processing of shrimp paste was natural fermentation, depends on shrimp it self and the presence of salt. The salt inhibits the growth of undesirable microorganism and allows the salt-tolerant lactic acid bacteria (LAB) to ferment the protein source to lactic acids. The objectives of this study were to characterize LAB isolated from Indonesian shrimp paste or "Terasi" with different times of fermentation (30, 60 and 90 days). Vitech analysis showed that there were four strains of the microorganism referred to as lactic acid bacteria (named: LABS1, LABS2, LABS3 and LABS4) with 95% sequence similarity. On the basis of biochemical, four isolates represented Lactobacillus, which the name Lactobacillus plantarum is proposed. L.plantarum was play role in resulting secondary metabolites, which gave umami flavor in shrimp paste.

Utilization of Encapsulated CaCO_3 in Liquid Core Capsules for Improving Lactic Acid Fermentation

International Nuclear Information System (INIS)

Boon-Beng, Lee; Nurul Ainina Zulkifli

2016-01-01

Lactic acid bacteria (LAB) have been used for food fermentation due to its fermentative ability to improve and enhance the quality of the end food products. However, the performance of LAB is affected as fermentation time elapsed because the microbial growth is inhibited by its end product, for example lactic acid. In this study, a new approach was introduced to reduce the product inhibition effect using CaCO_3 which is encapsulated in spherical liquid core capsules of diameter 3.5 mm and 3.6 mm produced through extrusion dripping method. The results showed that the pH and lactic acid concentration of LAB fermentation was well maintained by the capsules. The results of the fermentation conducted to control pH and lactic acid concentration using the capsules were better than those of the control set and comparable with that of the free CaCO_3 set. In addition, the viable cell concentration of L. casei shirota was high at the end of fermentation when the fermentation was conducted using the capsules. The results of this study suggested that the capsules have high potential to be applied for pH and lactic acid level control in LAB fermentation for various productions. (author)

Effect of different fermentation parameters on L-lactic acid production from liquid distillery stillage.

Science.gov (United States)

Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Vukašinović-Sekulić, Maja S; Rakin, Marica B; Nikolić, Svetlana B; Pejin, Jelena D; Bulatović, Maja L

2012-09-15

Expansion of lactic acid applications, predominantly for the preparation of biodegradable polymers increased the research interest for new, economically favourable production processes. Liquid stillage from bioethanol production can be an inexpensive, valuable source of nutrients for growth of lactic acid bacteria. Utilisation of residual biomass with spent fermentation media as a functional animal feed can greatly influence the process value and its ecological aspect. In this paper, the kinetics of lactic acid and biomass production on liquid stillage by Lactobacillus rhamnosus ATCC 7469 was studied. In addition, the impact of temperature, inoculum concentration, shaking and pH control by addition of CaCO(3) was evaluated. Maximal lactic acid yield of 73.4%, as well as high biomass production (3×10(8) CFU ml(-1)) were achieved under selected conditions (41°C, 5% (v/v) of inoculum, 1% (w/v) of CaCO(3), initial pH of 6.5 and shaking rate of 90 rpm). These results were achieved without supplementation of the stillage with nitrogen or mineral sources. Copyright © 2012 Elsevier Ltd. All rights reserved.

Comparative study of chemical composition, isolation and identification of micro-flora in traditional fermented camel milk products: Gariss, Suusac, and Shubat

Directory of Open Access Journals (Sweden)

Amal Bakr Shori

2012-06-01

Full Text Available The importance of micro-flora in dairy products cannot be overemphasised. Although there are scores of academic papers that elucidated on this subject, however, to the best knowledge of the researcher, there is no published paper that compares the composition of the traditional fermented camel milk products. Therefore, this paper aims to compare the preparation methods, chemical compositions, microbial counts and pH, isolation and identification of lactic acid bacteria, as well as yeasts in Gariss, Suusac, and Shubat. Through comparative analysis of previous existing published papers, the researcher discovered that different preparation methods of these three products have effects on their chemical compositions, microbial counts and pH, and as well as growth of lactic acid bacteria and yeast species.

Fermentation of Prefermented and Extruded Rice Flour by Lactic Acid Bacteria from Sikhae

DEFF Research Database (Denmark)

Lee, C. H.; Min, K. C.; Souane, M.

1992-01-01

of prefermentation of rice flour in solid-state with Bacillus laevolacticus and Saccharomyces cerevisiae, extrusion cooking and addition of soymilk as the substrate of lactic acid fermentation were tested. Extrusion cooking and prefermentation of rice increased the soluble solid and sugar contents before malt......The acid- and flavor-forming properties of Lactobacillus plantarum and Leuconostoc mesenteroides isolated from Sikhae, a Korean traditional lactic acid fermented fish product, were examined and compared to those of Lactobacillus casei and Lactococcus lactis subsp. diacetylactis DRC3. The effects...... digestion. The amount of sugar consumption during lactic fermentation varied with the type of bacteria. Leuconostoc mesenteroides(sikhae) and Lactobacillus plantarum(sikhae) increased up to 6 times of original cell number by 24 hrs of fermentation in rice + soymilk substrate, but Lactococcus lactis...

Correlation of Lactic Acid and Base Deficit Values Obtained From Arterial and Peripheral Venous Samples in a Pediatric Population During Intraoperative Care.

Science.gov (United States)

Bordes, Brianne M; Walia, Hina; Sebastian, Roby; Martin, David; Tumin, Dmitry; Tobias, Joseph D

2017-12-01

Lactic acid and base deficit (BD) values are frequently monitored in the intensive care unit and operating room setting to evaluate oxygenation, ventilation, cardiac output, and peripheral perfusion. Although generally obtained from an arterial cannula, such access may not always be available. The current study prospectively investigates the correlation of arterial and peripheral venous values of BD and lactic acid. The study cohort included 48 patients. Arterial BD values ranged from -8 to 4 mEq/L and peripheral venous BD values ranged from -8 to 4 mEq/L. Arterial lactic acid values ranged from 0.36 to 2.45 μmol/L and peripheral venous lactic acid values ranged from 0.38 to 4 μmol/L. The arterial BD (-0.4 ± 2.2 mEq/L) was not significantly different from the peripheral venous BD (-0.6 ± 2.2 mEq/L). The arterial lactic acid (1.0 ± 0.5 μmol/L) was not significantly different from the peripheral venous lactic acid (1.1 ± 0.6 μmol/L). Pearson correlation coefficients demonstrated a very high correlation between arterial and peripheral venous BD ( r = .88, P lactic acid ( r = .67, P lactic acid corresponded to a 0.9-unit increase in peripheral venous lactic acid (95% CI: 0.6-1.2; P lactic acid and BD values.

Thermal properties of poly (lactic acid)/milkweed composites

Science.gov (United States)

Currently, most polymer composites utilize petroleum-based materials that are non-degradable and difficult to recycle or incur substantial cost for disposal. Green composites can be used in nondurable limited applications. In order to determine the degree of compatibility between Poly (lactic Acid...

Lactic acid bacteria in a changing legislative environment

NARCIS (Netherlands)

Feord, J.

2002-01-01

The benefits of using lactic acid bacteria in the food chain, both through direct consumption and production of ingredients, are increasingly recognised by the food industry and consumers alike. The regulatory environment surrounding these products is diverse, covering foods and food ingredients,

Electrospinnability of poly lactic-co-glycolic acid (PLGA)

DEFF Research Database (Denmark)

Liu, Xiaoli; Baldursdottir, Stefania G.; Aho, Johanna

2017-01-01

PURPOSE: In this study, the electrospinnability of poly(lactic-co-glycolic acid) (PLGA) solutions was investigated, with a focus on understanding the influence of molecular weight of PLGA, solvent type and solvent composition on the physical properties of electrospun nanofibers. METHOD: Various s...

Calibration of a lactic-acid model for simulating biofilm-induced degradation of the dentin-composite interface.

Science.gov (United States)

Zhu, Laikuan; Li, Yuping; Carrera, Carola A; Chen, Yung-Chung; Li, Mingyu; Fok, Alex

2017-11-01

To verify and calibrate a chemical model for simulating the degradation of the dentin-composite interface induced by multi-species oral biofilms in vitro. Dentin-composite disks (5-mm dia.×2-mm thick) were made from bovine incisor roots and filled with either Z100™ (Z100) or Filtek™ LS (LS) composite. The disks, which were covered with nail varnish, but with one of the dentin-composite margins exposed, were immersed in lactic acid solution at pH 4.5 for up to 48h. Diametral compression was performed to measure the reduction in bond strength of the dentin-composite disks following acid challenge. Scanning electron microscopy (SEM) was used to examine decalcification of dentin and fracture modes of the disks. To better understand the degradation process, micro-computed tomography, in combination with a radiopaque dye (AgNO 3 ), was used to assess interfacial leakage in 3D longitudinally, while SEM was used to determine the path of leakage. One-way analysis of variance (ANOVA) was used to analyze the results, with the level of statistical significance set at pcomposite interface, instead. The degree of dentin demineralization, the reduction in debonding load and the modes of failure observed were very similar to those induced by multi-species oral biofilms found in the previous work. Leakage of AgNO 3 occurred mainly along the hybrid layer. The specimens filled with Z100 had a thicker hybrid layer (∼6.5μm), which exhibited more interfacial leakage than those filled with LS. The chemical model with lactic acid used in this study can induce degradation to the dentin-composite interface similar to those produced by multi-species biofilms. With appropriate calibration, this could provide an effective in vitro method for ageing composite restorations in assessing their potential clinical performance. Copyright © 2017 The Academy of Dental Materials. All rights reserved.

Production of D-lactic acid from sugarcane bagasse using steam-explosion

Science.gov (United States)

Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi

2012-03-01

This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.

Taurocholate Deconjugation and Cholesterol Binding by Indigenous Dadih Lactic Acid Bacteria

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USMAN PATO

2005-09-01

Full Text Available High serum cholesterol levels have been associated with an increased risk for human coronary heart disease. Lowering of serum cholesterol has been suggested to prevent the heart disease. To reduce serum cholesterol levels one may consumed diet supplementat of fermented dairy product such as dadih. Lactic acid bacteria present in dadih may alter serum cholesterol by directly bind to dietary cholesterol and/or deconjugation of bile salts. Acid and bile tolerance, deconjugation of sodium taurocholate, and the cholesterol-binding ability of lactic acid bacteria from dadih were examined. Among ten dadih lactic acid bacteria tested, six strains namely I-11, I-2775, K-5, I-6257, IS-7257, and B-4 could bind cholesterol and deconjugate sodium taurocholate. However, the last four strains were very sensitive to bile. Therefore, Lactobacillus fermentum I-11 and Leuconostoc lactis subsp. lactis I-2775 those were tolerant to acid and oxgall (bile and deconjugated sodium taurocholate and bound cholesterol could be recommended as probiotic to prevent coronary heart disease.

Production of D-lactic acid from sugarcane bagasse using steam-explosion

International Nuclear Information System (INIS)

Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi

2012-01-01

This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.

Efficient in situ separation and production of L-lactic acid by Bacillus coagulans using weak basic anion-exchange resin.

Science.gov (United States)

Zhang, Yitong; Qian, Zijun; Liu, Peng; Liu, Lei; Zheng, Zhaojuan; Ouyang, Jia

2018-02-01

To get rid of the dependence on lactic acid neutralizer, a simple and economical approach for efficient in situ separation and production of L-lactic acid was established by Bacillus coagulans using weak basic anion-exchange resin. During ten tested resins, the 335 weak basic anion-exchange resins demonstrated the highest adsorption capacity and selectivity for lactic acid recovery. The adsorption study of the 335 resins for lactic acid confirmed that it is an efficient adsorbent under fermentation condition. Langmuir models gave a good fit to the equilibrium data at 50 °C and the maximum adsorption capacity for lactic acid by 335 resins was about 402 mg/g. Adsorption kinetic experiments showed that pseudo-second-order kinetics model gave a good fit to the adsorption rate. When it was used for in situ fermentation, the yield of L-lactic acid by B. coagulans CC17 was close to traditional fermentation and still maintained at about 82% even after reuse by ten times. These results indicated that in situ separation and production of L-lactic acid using the 335 resins were efficient and feasible. This process could greatly reduce the dosage of neutralizing agent and potentially be used in industry.

Laboratory Evaluation of Synthetic Blends of l-(+)-Lactic Acid, Ammonia, and Ketones As Potential Attractants For Aedes aegypti.

Science.gov (United States)

Venkatesh, P M; Sen, A

2017-12-01

Attraction of Aedes aegypti to various binary, trinary, and quaternary blends of lactic acid and ketones with or without ammonia was studied using a dual choice olfactometer. A dose dependent attraction was observed in cases of single compounds where cyclopentanone attracted the highest percentage (36.9 ± 1.8%) of Ae. aegypti when tested alone. No significant difference was observed between the attraction levels of trinary and binary blends of lactic acid and acetone or butanone when tested against clear air. However, in competitive bioassays, the trinary blend of lactic acid, acetone, and butanone was significantly preferred over binary blends of individual compounds ( P lactic acid. However, acetylacetone acted as an attraction inhibitor when blended with other compounds. Cyclopentanone was attractive, but enhancement of attraction was not observed when blended with other components. Addition of ammonia to binary or trinary blends of lactic acid, acetone, and/or butanone did not increase the attraction significantly. In competitive bioassays, the blends containing ammonia were significantly preferred over the blends lacking ammonia ( P lactic acid, ammonia, acetone, and butanone was most attractive (65 ± 1.5%) and preferred blend of all other combinations.

Time related total lactic acid bacteria population diversity and ...

African Journals Online (AJOL)

user

2011-02-07

Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

Bio-Inspired Materials and Devices for Chemical and Biological Defense

Science.gov (United States)

2010-09-01

studies the acid system chosen (formic, lactic, acetic, propionic, ascorbic , malic) had significant effect on the product, particularly in terms of...desired on the substrate. Some of the simplest approaches to this include immobilization by poly(ethylene glycol) (PEG), cholesterol mixing, chemical...this is the liposome, typically a spherical lipid bilayer consisting of phospholipid and cholesterol layers which serve to isolate the interior of

Differentiation studies of predominant lactic acid bacteria isolated ...

African Journals Online (AJOL)

Twelve isolates known as weakly amylolytic lactic acid bacteria were isolated from different time during growol fermentation, a cassava based product from Indonesia. Differentiation tests of these strains were performed using molecular and phenotypic characterization. 16S subunit of the ribosomal RNA and phenylalanyl ...

Probiotic potential of noni juice fermented with lactic acid bacteria and bifidobacteria.

Science.gov (United States)

Wang, Chung-Yi; Ng, Chang-Chai; Su, Hsuan; Tzeng, Wen-Sheng; Shyu, Yuan-Tay

2009-01-01

The present study assesses the feasibility of noni as a raw substrate for the production of probiotic noni juice by lactic acid bacteria (Lactobacilluscasei and Lactobacillus plantarum) and bifidobacteria (Bifidobacteriumlongum). Changes in pH, acidity, sugar content, cell survival and antioxidant properties during fermentation were monitored. All tested strains grew well on noni juice, reaching nearly 10⁹ colony-forming units/ml after 48 h fermentation. L.casei produced less lactic acid than B.longum and L. plantarum. After 4 weeks of cold storage at 4°C, B.longum and L. plantarum survived under low-pH conditions in fermented noni juice. In contrast, L.casei exhibited no cell viability after 3 weeks. Moreover, noni juice fermented with B.longum had a high antioxidant capacity that did not differ significantly (P <0.05) from that of lactic acid bacteria. Finally, we found that B.longum and L. plantarum are optimal probiotics for fermentation with noni juice.

Amylolytic Enzymes Acquired from L-Lactic Acid Producing Enterococcus faecium K-1 and Improvement of Direct Lactic Acid Production from Cassava Starch.

Science.gov (United States)

Unban, Kridsada; Kanpiengjai, Apinun; Takata, Goro; Uechi, Keiko; Lee, Wen-Chien; Khanongnuch, Chartchai

2017-09-01

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112 kDa with optimal pH value and temperature measured of 7.0 and 40 °C, respectively. It was stable at a pH range of 6.0-7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba 2+ , Al 3+ , and Co 2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2 g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10 g/L cassava starch as the sole carbon source when cultivated at 37 °C for 48 h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150 g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.

Probiotic lactic acid bacteria – the fledgling cuckoos of the gut?

Directory of Open Access Journals (Sweden)

Arnold Berstad

2016-05-01

Full Text Available It is tempting to look at bacteria from our human egocentric point of view and label them as either ‘good’ or ‘bad’. However, a microbial society has its own system of government – ‘microcracy’ – and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being ‘friendly’ – they may instead behave like fledgling cuckoos.

Production of lactic acid from Starchy-based food substrates

African Journals Online (AJOL)

SARAH

2013-11-30

Nov 30, 2013 ... are rather costly. This necessitated ... found application in many industries and various commercial ... and Sharpe (MRS) agar for total lactic acid bacteria ..... An Economic ... of Enzymes and Microbial Technology, 26: 87-. 107.

Lactic acid production on liquid distillery stillage by Lactobacillus rhamnosus immobilized onto zeolite.

Science.gov (United States)

Djukić-Vuković, Aleksandra P; Mojović, Ljiljana V; Jokić, Bojan M; Nikolić, Svetlana B; Pejin, Jelena D

2013-05-01

In this study, lactic acid and biomass production on liquid distillery stillage from bioethanol production with Lactobacillus rhamnosus ATCC 7469 was studied. The cells were immobilized onto zeolite, a microporous aluminosilicate mineral and the lactic acid production with free and immobilized cells was compared. The immobilization allowed simple cell separation from the fermentation media and their reuse in repeated batch cycles. A number of viable cells of over 10(10) CFU g(-1) of zeolite was achieved at the end of fourth fermentation cycle. A maximal process productivity of 1.69 g L(-1), maximal lactic acid concentration of 42.19 g L(-1) and average yield coefficient of 0.96 g g(-1) were achieved in repeated batch fermentation on the liquid stillage without mineral or nitrogen supplementation. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Organoleptic and Physic Characteristics and Lactic Acid Contents of Yoghurt with Commercial Starter Added Bifidobacteria bifidum

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Tatik Khusniati

2012-10-01

Full Text Available Bifidobacteria bifidum is probiotic bacteria which inhibit negative bacteria in human ulcer. Adding B. bifidum in commercial yoghurt starter, may increase yoghurt quality. To know yoghurt quality, organoleptic and physic characteristics and lactic acidcontents of yoghurt with commercial starter added B. bifidum was observed. B. bifidum concentrations added were 1:4, 2:4, 3:4 (v/v. Organoleptic characteristics were conducted by 18 panelists, physics were visually detected and lactic acid contents were by titration method. The results show that accepted yoghurt characteristics were yoghurt with commercial starter added B. bifidum 1:4 (v/v, and fat yoghurt were more acceptable than that skim. The higher B. bifidum concentrations used, the stronger flavours (after expiry date and colours (at and after expiry date of yoghurt, while yoghurt homogenity decreased (at and after expiry date. Fat yoghurt flavours were stronger than that of skim. The higher B. bifidum concentrations and storage times, the higher yoghurt lactic acid contents. Lactic acid contents of fat yoghurt with various starters, were higher than that skim at storage 0-15 days. The fat yoghurt lactic acid contents were 0.99%-1.44%, while that skim were 0.95-1.20%. Based on organoleptic and physic characteristics and lactic acid contents, fat yoghurt were more acceptable that that skim.

Composition of lactic acid bacteria in dairy products and their effect on tourism development of inner Mongolia

Directory of Open Access Journals (Sweden)

Min Liu

2016-08-01

Full Text Available In recent years, the development of dairy industry in Inner Mongolia has accelerated its economic growth, and its grassland culture has become appealing to the public. As an important support industry for the economic development in tourism area of Inner Mongolia, dairy industry can create economic value for the development of tourism. In view of the importance of dairy products-the habitat of lactic acid bacteria, this study aims to reveal the composition of lactic acid bacteria in dairy products and isolate lactic acid bacteria resources. Firstly, we selected 60 traditional dairy product samples (from the pasture in scenic area of Inner Mongolia as the research objects. Based on the 16S rRNA gene sequence analysis, lactic acid bacteria in the samples were isolated and identified; Real-time quantitative polymerase chain reaction (q-PCR technology was applied to the comparative analysis on the population of dominant bacteria in samples. It was found that there were significant differences in the numbers of dominant bacteria in different dairy products. With the advantages of improving nutritional value and extending storage time of dairy products, lactic acid bacteria is contributive to the development of dairy industry, which further promotes the prosperity of economy and tourism. Therefore, it is of great importance to study the composition of lactic acid bacteria in dairy products.

Antimicrobial potential of triticale stillage after lactic acid fermentation with Lactobacillus fermentum PL-1

OpenAIRE

Kujundžić Žužana; Dimić Gordana R.; Markov Siniša L.; Kocić-Tanackov Sunčica D.; Mojović Ljiljana V.; Pejin Jelena D.; Marković Milica N.

2013-01-01

This study is concerned with the testing of antimicrobial activity of triticale stillage obtained after lactic fermentation by Lactobacillus fermentum PL-1. The antimicrobial tests were performed using the disc-diffusion and agar well diffusion methods. It was found that fermented triticale stillage after lactic acid fermentation exhibited an inhibitory effect towards tested Gram positive and Gram negative bacteria: Escherichia coli, Salmonella enteritidis,...

Effects of a series of acidic drugs on L-lactic acid transport by the monocarboxylate transporters MCT1 and MCT4.

Science.gov (United States)

Leung, Yat Hei; Belanger, Francois; Lu, Jennifer; Turgeon, Jacques; Michaud, Veronique

2018-03-07

Drug-induced myopathy is a serious side effect that often requires removal of a medication from a drug regimen. For most drugs, the underlying mechanism of drug-induced myopathy remains unclear. Monocarboxylate transporters (MCTs) mediate L-lactic acid transport, and inhibition of MCTs may potentially lead to perturbation of L-lactic acid accumulation and muscular disorders. Therefore, we hypothesized that L-lactic acid transport may be involved in the development of drug-induced myopathy. The aim of this study was to assess the inhibitory potential of 24 acidic drugs on L-lactic acid transport using breast cancer cell lines Hs578T and MDA-MB-231, which selectively express MCT1 and MCT4, respectively. The influx transport of L-lactic acid was minimally inhibited by all drugs tested. The efflux transport was next examined: loratadine (IC50: 10 and 61 µM) and atorvastatin (IC50: 78 and 41 µM) demonstrated the greatest potency for inhibition of L-lactic acid efflux by MCT1 and MCT4, respectively. Acidic drugs including fluvastatin, cerivastatin, simvastatin acid, lovastatin acid, irbesartan and losartan exhibited weak inhibitory potency on L-lactic acid efflux. Our results suggest that some acidic drugs, such as loratadine and atorvastatin, can inhibit the efflux transport of L-lactic acid. This inhibition may cause an accumulation of intracellular L-lactic acid leading to acidification and muscular disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Intermediate phase evolution in YBCO thin films grown by the TFA process

International Nuclear Information System (INIS)

Zalamova, K; Pomar, A; Palau, A; Puig, T; Obradors, X

2010-01-01

The YBCO thin film growth process from TFA precursors involves a complex reaction path which includes several oxide, fluoride and oxyfluoride intermediate phases, and the final microstructure and properties of the films are strongly influenced by the morphological and chemical evolution of these intermediate phases. In this work we present a study of the evolution of the intermediate phases involved in the TFA YBCO growth process under normal pressure conditions and we show that the oxygen partial pressure during pyrolysis of the TFA precursors is an important parameter. The Cu phase after the TFA pyrolysis can be either CuO, Cu 2 O or a mixture of both as the oxygen partial pressure is modified. The kinetics evolution of the intermediate phases has been determined for films pyrolysed in oxygen and nitrogen atmospheres and it is concluded that non-equilibrium phase transformations influence the reaction path towards epitaxial YBCO films and its microstructure. The intermediate phase evolution in these two series of films is summarized in kinetic phase diagrams.

Development of a LC-MS/MS Method for the Simultaneous Detection of Tricarboxylic Acid Cycle Intermediates in a Range of Biological Matrices

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Omar Al Kadhi

2017-01-01

Full Text Available It is now well-established that perturbations in the tricarboxylic acid (TCA cycle play an important role in the metabolic transformation occurring in cancer including that of the prostate. A method for simultaneous qualitative and quantitative analysis of TCA cycle intermediates in body fluids, tissues, and cultured cell lines of human origin was developed using a common C18 reversed-phase column by LC-MS/MS technique. This LC-MS/MS method for profiling TCA cycle intermediates offers significant advantages including simple and fast preparation of a wide range of human biological samples. The analytical method was validated according to the guideline of the Royal Society of Chemistry Analytical Methods Committee. The limits of detection were below 60 nM for most of the TCA intermediates with the exception of lactic and fumaric acids. The calibration curves of all TCA analytes showed linearity with correlation coefficients r2>0.9998. Recoveries were >95% for all TCA analytes. This method was established taking into consideration problems and limitations of existing techniques. We envisage that its application to different biological matrices will facilitate deeper understanding of the metabolic changes in the TCA cycle from in vitro, ex vivo, and in vivo studies.

CHARACTERIZATION OF AUTOCHTHONUS LACTIC FLORA OF A CAMPANIAN CHILLI CHEESE PRODUCED FROM RAW SHEEP MILK

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A. Mormile

2012-08-01

Full Text Available The natural lactic flora of the artisanal chilli “Tramonti” cheese, a typical product manufactured in the “Lattari mountains”, area of Salerno province (Italy, was investigated. Particular attention was paid to the growth dynamics assessment and to the molecular identification of the indigenous lactic acid bacteria involved in the ripening of this cheese made with raw sheep milk without starter cultures. One batch was monitored taking 4 sample on 0, 30, 50 and 105 ripening days. Lactobacillus and Lactococcus were enumerated and randomly isolated on MRS and LM17 agar (32ºC x 48h -mesophilic flora- and 42°C x 48h -thermophilic flora, respectively. N. 66 presumptive lactic acid bacteria isolates, gram positive and catalase negative, were genotipically identified by Ribotyping. Mesophilic Lactobacillus remained at levels of 107 cfu/g during whole maturation time and thermophilic Lactobacillus, from initial values of 105 cfu/g, reached concentratios of 106 cfu/g at the end of maturation. Mesophilic and thermophilic Lactococcus showed, on average, levels of 106 since the beginning of the ripening. Ribotyping allowed to detect 4 lactic acid bacteria species: Enterococcus faecium (65,15%, Lactococcus lactis spp. cremoris (24,24%, Enterococcus faecalis (6,06% and Enterococcus durans (4,54%, showing the diversity of indigenous lactic acid bacteria of chilli “Tramonti” cheese.

Diversity and distribution of culturable lactic acid bacterial species in Indonesian Sayur Asin

OpenAIRE

Mangunwardoyo, Wibowo; Abinawanto,; Salamah, Andi; Sukara, Endang; Sulistiani,; Dinoto, Achmad

2016-01-01

Background and Objectives: Lactic acid bacteria (LAB) play important roles in processing of Sayur Asin (spontaneously fermented mustard). Unfortunately, information about LAB in Indonesian Sayur Asin, prepared by traditional manufactures which is important as baseline data for maintenance of food quality and safety, is unclear. The aim of this study was to describe the diversity and distribution of culturable lactic acid bacteria in Sayur Asin of Indonesia.Materials and Methods: Four Sayur As...

The effects of adding lactic acid bacteria and cellulase in oil palm (Elais guineensis Jacq.) frond silages on fermentation quality, chemical composition and in vitro digestibility

NARCIS (Netherlands)

Ebrahimi, Mahdi; Rajion, Mohamed Ali; Goh, Yong Meng; Farjam, Abdoreza Soleimani; Sazili, Awis Qurni; Schonewille, Jan Thomas

2014-01-01

The main objective of the current study was to evaluate whether oil palm frond (OPF) can be successfully ensiled without or with the additives cellulase or lactic acid bacteria (LAB). Thus, fresh OPF was ensiled either without additives or with cellulase or LAB or their combination. Ensiling was

Refractory Lactic Acidosis in Small Cell Carcinoma of the Lung

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Daniel J. Oh

2017-01-01

Full Text Available Background. Elevated lactate levels in critically ill patients are most often thought to be indicative of relative tissue hypoxia or type A lactic acidosis. Shock, severe anemia, and thromboembolic events can all cause elevated lactate due to tissue hypoperfusion, as well as the mitochondrial dysfunction thought to occur in sepsis and other critically ill states. Malignancy can also lead to elevation in lactate, a phenomenon described as type B lactic acidosis, which is much less commonly encountered in the critically ill. Case Presentation. We present the case of a 73-year-old Caucasian woman with type 2 diabetes and hypertension who presented with abdominal pain, nausea, vomiting, nonbloody diarrhea, and weight loss over five weeks and was found to have unexplained refractory lactic acidosis despite fluids and antibiotics. She was later diagnosed with small cell carcinoma of the lung. Conclusions. In this case report, we describe a critically ill patient whose elevated lactate was incorrectly attributed to her acute illness, when in truth it was an indicator of an underlying, as yet undiagnosed, malignancy. We believe this case is instructive to the critical care clinician as a reminder of the importance of considering malignancy on the differential diagnosis of a patient presenting with elevated lactate out of proportion to their critical illness.

Synthesis of copolymer from lactic acid-polyethylene terephthalate ...

African Journals Online (AJOL)

Bio-plastic has been a need of the hour for the past few decades and the usage of lactic acid (LA) in the production of bio plastic opens a new ... of the environment and also helping in the production of bio-degradable plastics in the run.

Lactic Acid Bacteria Differentially Activate Natural Killer Cells

DEFF Research Database (Denmark)

Fink, Lisbeth Nielsen; Christensen, Hanne Risager; Frøkiær, Hanne

antigen presenting cells and T-cells. Bacteria translocating across the gastrointestinal mucosa are presumed to gain access to NK cell compartments, as consumption of certain strains of lactic acid bacteria has been shown to increase in vivo NK cytotoxic activity. On-going research in our lab aims...

Lactic acid and Lactates in Health and wellness

NARCIS (Netherlands)

Gertjan Schaafsma; Victor Schreurs

2010-01-01

This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a

High titer L-lactic acid production from corn stover with minimum wastewater generation and techno-economic evaluation based on Aspen plus modeling.

Science.gov (United States)

Liu, Gang; Sun, Jiaoe; Zhang, Jian; Tu, Yi; Bao, Jie

2015-12-01

Technological potentials of l-lactic acid production from corn stover feedstock were investigated by experimental and techno-economic studies. An optimal performance with 104.5 g/L in l-lactic acid titer and 71.5% in overall yield from cellulose in corn stover to l-lactic acid using an engineered Pediococcus acidilactici strain were obtained by overcoming several technical barriers. A rigorous Aspen plus model for l-lactic acid production starting from dry dilute acid pretreated and biodetoxified corn stover was developed. The techno-economic analysis shows that the minimum l-lactic acid selling price (MLSP) was $0.523 per kg, which was close to that of the commercial l-lactic acid produced from starch feedstock, and 24% less expensive than that of ethanol from corn stover, even though the xylose utilization was not considered. The study provided a prototype of industrial application and an evaluation model for high titer l-lactic acid production from lignocellulose feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of soymilk fermentation with a lactic culture

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Martha Cecilia Quicazán

2001-07-01

Full Text Available Soymilk, the protein slurry extracted in water from soybeans, obtained by means of a process tested previously at ICTA (the National University of Colombia's Institute of Food Science and Technology, was fermented by using a thermophyllic lactic culture consisting of L delbrueckii ss. bulgaricus, L. delbrueckii ss. lactis and S. salivarius ss. thermophilus. The soymilk composition was standardised (before fermentation, regarding solids and protein contení, by means of Brix0 as process variable. Soymilk was fermented by applying those same basic operations followed in cow milk fermentation. Acidification was assessed by evaluating pH, titrable acidity and organic acid production during the process by HPLC in an ionic exclusion column. Reologyc property modification was studied and compared with that for cow milk. It was proved that, despite the absence of lactose as substrate, soymilk acidification during this process can be explained by lactic acid production and that soymilk solid content influences acid production and changes in viscosity.

Prolonged local anesthetic action through slow release from poly (lactic acid co castor oil).

Science.gov (United States)

Sokolsky-Papkov, Marina; Golovanevski, Ludmila; Domb, Abraham J; Weiniger, Carolyn F

2009-01-01

To evaluate a new formulation of bupivacaine loaded in an injectable fatty acid based biodegradable polymer poly(lactic acid co castor oil) in prolonging motor and sensory block when injected locally. The polyesters were synthesized from DL: -lactic acid and castor oil with feed ratio of 4:6 and 3:7 w/w. Bupivacaine was dispersed in poly(fatty ester) liquid and tested for drug release in vitro. The polymer p(DLLA:CO) 3:7 loaded with 10% bupivacaine was injected through a 22G needle close to the sciatic nerve of ICR mice and the duration of sensory and motor nerve blockade was measured. The DL: -lactic acid co castor oil p(DLLA:CO) 3:7 released 65% of the incorporated bupivacaine during 1 week in vitro. Single injection of 10% bupivacaine loaded into this polymer caused motor block that lasted 24 h and sensory block that lasted 48 h. Previously we developed a ricinoleic acid based polymer with incorporated bupivacaine which prolonged anesthesia to 30 h. The new polymer poly(lactic acid co castor oil) 3:7 provides slow release of effective doses of the incorporated local anesthetic agent and prolongs anesthesia to 48 h.

Blends of low molecular weight of poly lactic acid (PLA) with gondorukem (gum rosin)

Science.gov (United States)

Kaavessina, Mujtahid; Distantina, Sperisa; Chafidz, Achmad; Utama, Aditya; Anggraeni, Venisa Mega Puteri

2018-02-01

The utilization of plastic was increasing as well as the increasing its demand in wide range application. Consequently, the number of plastic litter will increase and make more serious environmental problems. This research concerns to minimize waste problems by designing biodegradable plastic. In this research, biodegradable plastic was made of poly lactic acid (PLA) and gondorukem (Gum rosin, Resina colophonium) as the plasticizer. The effect of gondorukem towards PLA properties such as rheology and degradability was investigated. The research divided into two steps: (i) the polycondensation of lactic acid (LA) and (ii) modification of obtained poly lactic acid. In the first step, polycondensation was done in N2 atmosphere (138°C) for 30 hours and added 0.1 %w of SnCl2 as catalyst. Bulk modification was conducted by blending of gondurukem in varied weight (0.5, 1, and 2 g in 10 g of PLA). Furthermore, the modified PLA was analyzed its molecular structure, biodegradability and rheological property. The presence of gondorukem enhanced the biodegradability of poly lactic acid. Gondorukem could act as the plasticizer. It is confirmed that the complex viscosity of PLA melt decreased upon the addition of gondorukem

Probing the Catalytic Mechanism of S-Ribosylhomocysteinase (LuxS) with Catalytic Intermediates and Substrate Analogues

Energy Technology Data Exchange (ETDEWEB)

Gopishetty, Bhaskar; Zhu, Jinge; Rajan, Rakhi; Sobczak, Adam J.; Wnuk, Stanislaw F.; Bell, Charles E.; Pei, Dehua; (OSU); (FIU)

2009-05-12

S-Ribosylhomocysteinase (LuxS) cleaves the thioether bond in S-ribosylhomocysteine (SRH) to produce homocysteine (Hcys) and 4,5-dihydroxy-2,3-pentanedione (DPD), the precursor of the type II bacterial quorum sensing molecule (AI-2). The catalytic mechanism of LuxS comprises three distinct reaction steps. The first step involves carbonyl migration from the C1 carbon of ribose to C2 and the formation of a 2-ketone intermediate. The second step shifts the C=O group from the C2 to C3 position to produce a 3-ketone intermediate. In the final step, the 3-ketone intermediate undergoes a {beta}-elimination reaction resulting in the cleavage of the thioether bond. In this work, the 3-ketone intermediate was chemically synthesized and shown to be chemically and kinetically competent in the LuxS catalytic pathway. Substrate analogues halogenated at the C3 position of ribose were synthesized and reacted as time-dependent inhibitors of LuxS. The time dependence was caused by enzyme-catalyzed elimination of halide ions. Examination of the kinetics of halide release and decay of the 3-ketone intermediate catalyzed by wild-type and mutant LuxS enzymes revealed that Cys-84 is the general base responsible for proton abstraction in the three reaction steps, whereas Glu-57 likely facilitates substrate binding and proton transfer during catalysis.

Characterization of airag collected in Ulaanbaatar, Mongolia with emphasis on isolated lactic acid bacteria.

Science.gov (United States)

Choi, Suk-Ho

2016-01-01

Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

Viability of Lactic Acid Bacteria Isolated from Kombucha Tea Against Low pH and Bile Salt

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Ni Nyoman Puspawati

2016-03-01

Full Text Available Kombucha tea is a functional drink fermented by various types of microbes. Kombucha tea is also a source of lactic acid bacteria that can maintain the balance of the microflora of the digestive tract which can improve the health of the human body. Lactic acid bacteria can act as a probiotic if it is able to survive to the human gastrointestinal tract, where in order to reach the digestive tract, lactic acid bacteria has to be resistant to the low pH in the stomach and bile salts. The purpose of this study was to determine the level of resistance of lactic acid bacteria in kombucha tea against low pH and bile salts. This study uses 20 isolates, each of these isolates were tested to the resistance of low pH 2.0 and 0.5 % bile salts with incubation time of 4 hours. The results indicated that from 20 isolates of lactic acid bacteria that were obtained from kombucha tea, 15 isolates were resistant to low pH and 13 isolates were resistant to bile salts. The isolates have a huge potential to be developed as a probiotic candidate that can contribute greatly to the health of the digestive tract.

Release of Polyphenols Is the Major Factor Influencing the Bioconversion of Rice Straw to Lactic Acid.

Science.gov (United States)

Chen, Xingxuan; Xue, Yiyun; Hu, Jiajun; Tsang, Yiu Fai; Gao, Min-Tian

2017-11-01

In this study, we found that p-coumaric acid (p-CA), ferulic acid (FA), and condensed tannins were released from rice straw during saccharification. The presence of polyphenols prolonged the lag phase and lowered the productivity of lactic acid. p-CA was identified as a key inhibitor. Tannins had a lower inhibitory effect than p-CA; FA had little inhibitory effect. Acid, alkaline, and ball milling pretreatments elicited different levels of polyphenol release from rice straw. Due to the different levels of polyphenol release in the pretreatment step, the enzymatic hydrolysates contained different concentrations of polyphenols. Compared with fermentation with a synthetic medium, fermentation with the hydrolysates of ball-milled rice straw provided much lower productivity and yield of lactic acid due to the presence of polyphenols. Removal of these compounds played an important role in lactic acid fermentation. When rice straw was alkaline pretreated, the hydrolysates contained few phenolic compounds, resulting in high productivity and yield of lactic acid (1.8 g/L/h and 26.7 g/100 g straw), which were comparable to those in a synthetic medium. This indicates that there is a correlation between removal of phenolic compounds and efficiency in lactic acid fermentation.

Inhibitory Properties of Lactic Acid Bacteria against Moulds Associated with Spoilage of Bakery Products

OpenAIRE

I. A. Adesina; A. O. Ojokoh; D. J. Arotupin

2017-01-01

Aim: To evaluate the potentiality of LAB strains isolated from different fermented products to inhibit moulds associated with spoilage of bakery products. Methodology: Lactic acid bacterial (LAB) strains obtained from fermented products (“burukutu”, “pito”, yoghurt, and “iru”) were screened for antifungal activity against moulds (Aspergillus flavus, Aspergillus fumigatus, Aspergillus repens and Penicillium sp.) isolated from spoilt bakery products. Inhibitory activities of the lactic acid...

Chemical compatibility and properties of suspension plasma-sprayed SrTiO3-based anodes for intermediate-temperature solid oxide fuel cells

Science.gov (United States)

Zhang, Shan-Lin; Li, Cheng-Xin; Li, Chang-Jiu

2014-10-01

La-doped strontium titanate (LST) is a promising, redox-stable perovskite material for direct hydrocarbon oxidation anodes in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, nano-sized LST and Sm-doped ceria (SDC) powders are produced by the sol-gel and glycine-nitrate processes, respectively. The chemical compatibility between LST and electrolyte materials is studied. A LST-SDC composite anode is prepared by suspension plasma spraying (SPS). The effects of annealing conditions on the phase structure, microstructure, and chemical stability of the LST-SDC composite anode are investigated. The results indicate that the suspension plasma-sprayed LST-SDC anode has the same phase structure as the original powders. LST exhibits a good chemical compatibility with SDC and Mg/Sr-doped lanthanum gallate (LSGM). The anode has a porosity of ∼40% with a finely porous structure that provides high gas permeability and a long three-phase boundary for the anode reaction. Single cells assembled with the LST-SDC anode, La0.8Sr0.2Ga0.8Mg0.2O3 electrolyte, and La0.8Sr0.2CoO3-SDC cathode show a good performance at 650-800 °C. The annealing reduces the impedances due to the enhancement in the bonding between the particles in the anode and interface of anode and LSGM electrolyte, thus improving the output performance of the cell.

original article antimicrobial susceptibility pattern of lactic acid

African Journals Online (AJOL)

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Abstract. Currently, the efficacies of antimicrobials have been threatened due to the development of resistance to antibiotics by some microorganisms. Lactic acid bacteria (LAB) from fermented products, may act as reservoir of antimicrobial resistance-genes that could be transferred to pathogens, either in the food matrix or ...

Efficient production of L-lactic acid by newly isolated thermophilic Bacillus coagulans WCP10-4 with high glucose tolerance.

Science.gov (United States)

Zhou, Xingding; Ye, Lidan; Wu, Jin Chuan

2013-05-01

A thermophilic Bacillus coagulans WCP10-4 with tolerance to high concentration of glucose was isolated from soil and used to produce optically pure L-lactic acid from glucose and starch. In batch fermentation at pH 6.0, 240 g/L of glucose was completely consumed giving 210 g/L of L-lactic acid with a yield of 95 % and a productivity of 3.5 g/L/h. In simultaneous saccharification and fermentation at 50 °C without sterilizing the medium, 200 g/L of corn starch was completely consumed producing 202.0 g/L of L-lactic acid. To the best of our knowledge, this strain shows the highest osmotic tolerance to glucose among the strains ever reported for lactic acid production. This is the first report of simultaneous saccharification and fermentation of starch for lactic acid production under a non-sterilized condition.

DNA fingerprinting of lactic acid bacteria in sauerkraut fermentations.

Science.gov (United States)

Plengvidhya, Vethachai; Breidt, Fredrick; Lu, Zhongjing; Fleming, Henry P

2007-12-01

Previous studies using traditional biochemical identification methods to study the ecology of commercial sauerkraut fermentations revealed that four species of lactic acid bacteria, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis, were the primary microorganisms in these fermentations. In this study, 686 isolates were collected from four commercial fermentations and analyzed by DNA fingerprinting. The results indicate that the species of lactic acid bacteria present in sauerkraut fermentations are more diverse than previously reported and include Leuconostoc citreum, Leuconostoc argentinum, Lactobacillus paraplantarum, Lactobacillus coryniformis, and Weissella sp. The newly identified species Leuconostoc fallax was also found. Unexpectedly, only two isolates of P. pentosaceus and 15 isolates of L. brevis were recovered during this study. A better understanding of the microbiota may aid in the development of low-salt fermentations, which may have altered microflora and altered sensory characteristics.

Radiation induced crystallinity damage in poly(L-lactic acid)

CERN Document Server

Kantoglu, O

2002-01-01

The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

Sustainable production of acetaldehyde from lactic acid over the carbon catalysts

Energy Technology Data Exchange (ETDEWEB)

Tang, Congming; Peng, Jiansheng; Li, Xinli; Zhai, Zhanjie; Gao, Hejun; Liao, Yunwen [China West Normal University, Nanchong (China); Bai, Wei; Jiang, Ning [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu (China)

2016-01-15

The synthesis of acetaldehyde from lactic acid over the carbon material catalysts was investigated. The carbon materials were characterized by scanning electron microscopy for morphologic features, by X-ray diffraction for crystal phases, by Fourier transform infrared spectroscopy for functional group structures, by N2 sorption for specific surface area and by ammonia temperature-programed desorption for acidity, respectively. Among the tested carbon catalysts, mesoporous carbon displayed the most excellent catalytic performance. By acidity analysis, the medium acidity is a crucial factor for catalytic performance: more medium acidity favored the formation of acetaldehyde from lactic acid. To verify, we compared the catalytic performance of fresh activated carbon with that of the activated carbon treated by nitric acid. Similarly, the modified activated carbon also displayed better activity due to a drastic increase of medium acidity amount. However, in contrast to fresh carbon nanotube, the treated sample displayed worse activity due to decrease of medium acidity amount. The effect of reaction temperature and time on stream on the catalytic performance was also investigated. Under the optimal reaction conditions, 100% lactic acid conversion and 91.6% acetaldehyde selectivity were achieved over the mesoporous carbon catalyst.

Profound neonatal hypoglycemia and lactic acidosis caused by pyridoxine-dependent epilepsy.

Science.gov (United States)

Mercimek-Mahmutoglu, Saadet; Horvath, Gabriella A; Coulter-Mackie, Marion; Nelson, Tanya; Waters, Paula J; Sargent, Michael; Struys, Eduard; Jakobs, Cornelis; Stockler-Ipsiroglu, Sylvia; Connolly, Mary B

2012-05-01

Pyridoxine-dependent epilepsy (PDE) was first described in 1954. The ALDH7A1 gene mutations resulting in α-aminoadipic semialdehyde dehydrogenase deficiency as a cause of PDE was identified only in 2005. Neonatal epileptic encephalopathy is the presenting feature in >50% of patients with classic PDE. We report the case of a 13-month-old girl with profound neonatal hypoglycemia (0.6 mmol/L; reference range >2.4), lactic acidosis (11 mmol/L; reference range A (p.Val278Val), and a novel putative pathogenic missense mutation c.1192G>C (p.Gly398Arg) in the ALDH7A1 gene. She has been seizure-free since 1.5 months of age on treatment with pyridoxine alone. She has motor delay and central hypotonia but normal language and social development at the age of 13 months. This case is the first description of a patient with PDE due to mutations in the ALDH7A1 gene who presented with profound neonatal hypoglycemia and lactic acidosis masquerading as a neonatal-onset gluconeogenesis defect. PDE should be included in the differential diagnosis of hypoglycemia and lactic acidosis in addition to medically refractory neonatal seizures.

Lactobacilli inactivate Chlamydia trachomatis through lactic acid but not H2O2.

Directory of Open Access Journals (Sweden)

Zheng Gong

Full Text Available Lactobacillus species dominate the microbiome in the lower genital tract of most reproductive-age women. Producing lactic acid and H2O2, lactobacilli are believed to play an important role in prevention of colonization by and growth of pathogens. However, to date, there have been no reported studies characterizing how lactobacilli interact with Chlamydia trachomatis, a leading sexually transmitted bacterium. In this report, we demonstrate inactivation of C. trachomatis infectivity by culture media conditioned by Lactobacillus crispatus, L. gasseri and L. jensenii, known to be dominating organisms in the human vaginal microbiome. Lactobacillus still cultures produced lactic acid, leading to time- and concentration-dependent killing of C. trachomatis. Neutralization of the acidic media completely reversed chlamydia killing. Addition of lactic acid into Lactobacillus-unconditioned growth medium recapitulated the chlamydiacidal activity of conditioned media. The H2O2 concentrations in the still cultures were found to be comparable to those reported for the cervicovaginal fluid, but insufficient to inactivate chlamydiae. Aeration of Lactobacillus cultures by shaking markedly induced H2O2 production, but strongly inhibited Lactobacillus growth and lactic acid production, and thus severely affected acidification, leading to significantly reduced chlamydiacidal efficiency. These observations indicate lactobacilli inactivate chlamydiae primarily through maintaining acidity in a relatively hypoxic environment in the vaginal lumen with limited H2O2, which is consistent with the notion that women with higher vaginal pH are more prone to sexually transmitted C. trachomatis infection. In addition to lactic acid, formic acid and acetic acid also exhibited potent chlamydiacidal activities. Taken together, our findings imply that lowering the vaginal pH through engineering of the vaginal microbiome and other means will make women less susceptible to C

[Applications of nitrile converting enzymes in the production of fine chemicals].

Science.gov (United States)

Zheng, Yuguo; Xue, Yaping; Liu, Zhiqiang; Zheng, Renchao; Shen, Yinchu

2009-12-01

Nitriles are an important type of synthetic intermediates in the production of fine chemicals because of their easy preparations and versatile transformations. The traditional chemical conversion of nitriles to carboxylic acids and amides is feasible but it requires relatively harsh conditions of heat, acid or alkali. Nitrile converting enzymes (nitrilase, nitrile hydratase and amidase) which are used as biocatalyst for the production of fine chemicals have attracted substantial interest because of their ability to convert readily available nitriles into the corresponding higher value amides or acids under mild conditions with excellent chemo-, regio- and stereo-selectivities. Many nitrile converting enzymes have been explored and widely used for the production of fine chemicals. In this paper, various examples of biocatalytic synthesis of pharmaceuticals and their intermediates, agrochemicals and their intermediates, food and feed additives, and other fine chemicals are presented. In the near future, an increasing number of novel nitrile converting enzymes will be screened and their potential in the production of useful fine chemicals will be further exploited.

Increased iron bioavailability from lactic-fermented vegetables is likely an effect of promoting the formation of ferric iron (Fe(3+)).

Science.gov (United States)

Scheers, Nathalie; Rossander-Hulthen, Lena; Torsdottir, Inga; Sandberg, Ann-Sofie

2016-02-01

Lactic fermentation of foods increases the availability of iron as shown in a number of studies throughout the years. Several explanations have been provided such as decreased content of inhibitory phytate, increased solubility of iron, and increased content of lactic acid in the fermented product. However, to our knowledge, there are no data to support that the bioavailability of iron is affected by lactic fermentation. The objective of the present study was to investigate whether the bioavailability of iron from a vegetable mix was affected by lactic fermentation and to propose a mechanism for such an event, by conducting human and cell (Caco-2, HepG2) studies and iron speciation measurements (voltammetry). We also investigated whether the absorption of zinc was affected by the lactic fermentation. In human subjects, we observed that lactic-fermented vegetables served with both a high-phytate and low-phytate meal increased the absorption of iron, but not zinc. In vitro digested fermented vegetables were able to provoke a greater hepcidin response per ng Fe than fresh vegetables, indicating that Fe in the fermented mixes was more bioavailable, independent on the soluble Fe content. We measured that hydrated Fe(3+) species were increased after the lactic fermentation, while there was no significant change in hydrated Fe(2+). Furthermore, lactate addition to Caco-2 cells did not affect ferritin formation in response to Fe nor did lactate affect the hepcidin response in the Caco-2/HepG2 cell system. The mechanism for the increased bioavailability of iron from lactic-fermented vegetables is likely an effect of the increase in ferric iron (Fe(3+)) species caused by the lactic fermentation. No effect on zinc bioavailability was observed.

Antibacterial Activity of Lactic Acid Bacteria Isolated from Salad ...

African Journals Online (AJOL)

To determine the inhibitory capacity of lactic acid bacteria (LAB) due to the action of antagonistic substances, 8 members of the LAB group namely, Lactobacillus brevis, Lactobacillus casei, Lactobacillus cellebiosuis, Lactobacillus delbruesckii, Lactobacillus fermentum, Lactobacillus plantarum, Leuconostoc mesenteroides ...

Characterization of lactic acid bacteria isolated from indigenous dahi ...

African Journals Online (AJOL)

Diversity and density of lactic acid bacteria from indigenous dahi were studied by the determination of morphological, cultural, physiological and biochemical characteristics. A total of 143 isolates were identified phenotypically and divided into three genera: Lactobacillus, Lactococcus and Streptococcus.

Lactic acid bacteria population dynamics during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine.

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Pardali, Eleni; Paramithiotis, Spiros; Papadelli, Marina; Mataragas, Marios; Drosinos, Eleftherios H

2017-06-01

The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30 °C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.

Antimicrobial properties of lactic acid bacteria isolated from uruguayan artisan cheese

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Martín Fraga Cotelo

2013-12-01

Full Text Available Uruguayan artisan cheese is elaborated with raw milk and non-commercial starters. The associated native microbiota may include lactic acid bacteria and also potentially pathogenic bacteria. Lactic acid bacteria were isolated from artisan cheese, raw milk, and non-commercial starter cultures, and their potential bacteriocin production was assessed. A culture collection of 509 isolates was obtained, and five isolates were bacteriocin-producers and were identified as Enterococcus durans,Lactobacillus casei, and Lactococcus lactis. No evidence of potential virulence factors were found in E. durans strains. These are promising results in terms of using these native strains for cheese manufacture and to obtain safe products.

Biodegradability and Biocompatibility Study of Poly(Chitosan-g-lactic Acid Scaffolds

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Zhe Zhang

2012-03-01

Full Text Available A biodegradable, biocompatible poly(chitosan-g-lactic acid (PCLA scaffold was prepared and evaluated in vitro and in vivo. The PCLA scaffold was obtained by grafting lactic acid (LA onto the amino groups on chitosan (CS without a catalyst. The PCLA scaffolds were characterized by Fourier Transform infrared spectroscopy (FT-IR and scanning electron microscopy (SEM. The biodegradabilty was determined by mass loss in vitro, and degradation in vivo as a function of feed ratio of LA/CS. Bone marrow mesenchymal stem cell (BMSC culture experiments and histological examination were performed to evaluate the PCLA scaffolds’ biocompatibility. The results indicated that PCLA was promising for tissue engineering application.

Dichloroacetate prevents hypoxic lactic acidosis in rats | Bosco ...

African Journals Online (AJOL)

acidosis, particularly in the cerebral tissue and the cerebrospinal fluid. Assess the efficiency of dichloroacetate in the prevention of hypoxia-induced lactic acidosis. We used adult rats, 3 months old, with a weight of 250-300 grams. Anesthesia was achieved by intraperitoneal injection of pentobarbital (Nembutal®), at the ...

Intermediate treatments

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John R. Jones; Wayne D. Shepperd

1985-01-01

Intermediate treatments are those applied after a new stand is successfully established and before the final harvest. These include not only intermediate cuttings - primarily thinning - but also fertilization, irrigation, and protection of the stand from damaging agents.

Effects of ensiling treatments on lactic acid production and supplementary methane formation of maize and amaranth--an advanced green biorefining approach.

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Haag, Nicola Leonard; Nägele, Hans-Joachim; Fritz, Thomas; Oechsner, Hans

2015-02-01

A green biorefinery enables the material and energetic use of biomass via lactic acid and methane production. Different ensiling techniques were applied to maize and amaranth with the aim to increase the amount of lactic acid in the silage. In addition the methane formation potential of the ensiled samples and the remaining solid residues after separating the organic juice were assessed. Treating maize with homofermentative lactic acid bacteria in combination with carbonated lime increased the amount of lactic acid about 91.9%. For amaranth no additional lactic acid production was obtained by treating the raw material. Specific methane yields for the solid residues of amaranth were significantly lower in comparison to the corresponding silages. The most promising treatment resulted in a production of 127.9±4.1 g kg(-1) DM lactic acid and a specific methane yield for the solid residue of 349.5±6.6 lN kg(-1) ODM. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of total solid content and pretreatment on the production of lactic acid from mixed culture dark fermentation of food waste.

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Yousuf, Ahasa; Bastidas-Oyanedel, Juan-Rodrigo; Schmidt, Jens Ejbye

2018-04-28

Food waste landfilling causes environmental degradation, and this work assesses a sustainable food valorization technique. In this study, food waste is converted into lactic acid in a batch assembly by dark fermentation without pH control and without the addition of external inoculum at 37 °C. The effect of total solid (TS), enzymatic and aeration pretreatment was investigated on liquid products concentration and product yield. The maximum possible TS content was 34% of enzymatic pretreated waste, and showed the highest lactic acid concentration of 52 g/L, with a lactic acid selectivity of 0.6 g lactic /g totalacids . The results indicated that aeration pretreatment does not significantly improve product concentration or yield. Non-pretreated waste in a 29% TS system showed a lactic acid concentration of 31 g/L. The results showed that enzymatic pretreated waste at TS of 34% results in the highest production of lactic acid. Copyright © 2018 Elsevier Ltd. All rights reserved.

Antibacterial Activity of Lactic Acid Bacteria Isolated from Healthy ...

African Journals Online (AJOL)

Abstract. Lactic acid bacteria (LAB), namely, Lactobacillus acidophilus 1, Lactobacillus acidophilus 2, Lactobacillus brevis 1, Lactobacillus rhamnosus 1, Lactococcus lactis subsp. lactis 1, Lactococcus lactis subsp. lactis 2, Lactococcus raffinolactis 1, Pediococcus acidilactici 1, Pediococcus pentosaceus 1, and Pediococcus ...

Styrene-Assisted Maleic Anhydride Grafted Poly(lactic acid as an Effective Compatibilizer for Wood Flour/Poly(lactic acid Bio-Composites

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Jun Du

2017-11-01

Full Text Available This study aimed to evaluate the effect of styrene-assisted maleic anhydride-grafted poly(lactic acid (PLA-g-St/MAH on the interfacial properties of wood flour/poly(lactic acid (PLA bio-composites. PLA-g-St/MAH was synthesized by free-radical melt grafting using styrene as a comonomer and dicumyl peroxide as an initiator. The structure of PLA-g-St/MAH was characterized by Fourier transform infrared spectroscopy. Wood flour/PLA composites were prepared by compression molding using PLA-g-St/MAH as a compatibilizer. The effects of PLA-g-St/MAH on the rheological and mechanical properties, as well as on the fractured surface morphology of the composites were investigated. Results indicated that storage modulus, complex viscosity, equilibrium torque, and shear heat were significantly increased. The mechanical properties of the wood flour/PLA composites were also significantly increased after the addition of PLA-g-St/MAH. The maximum values were achieved at the loading rate of 3 wt % because of the improved interfacial adhesion between the wood flour and the PLA matrix.

Physicochemical properties of poly(lactic acid-co-glycolic acid film modified via blending with poly(butyl acrylate-co-methyl methacrylate

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Guoquan Zhu

2013-01-01

Full Text Available A series of poly(lactic acid-co-glycolic acid (PLGA/poly(butyl acrylate-co-methyl methacrylate (P(BA-co-MMA blend films with different P(BA-co-MMA mole contents were prepared by casting the polymer blend solution in chloroform. Surface morphologies of the PLGAP(BA-co-MMA blend films were studied by scanning electron microscopy (SEM. Thermal, mechanical, and chemical properties of PLGAP(BA-co-MMA blend films were investigated by differential scanning calorimeter (DSC, thermogravimetric analysis (TGA, tensile tests, and surface contact angle tests. The introduction of P(BA-co-MMA could modify the properties of PLGA films.

Direct lactic acid fermentation of Jerusalem artichoke tuber extract using Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis.

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Choi, Hwa-Young; Ryu, Hee-Kyoung; Park, Kyung-Min; Lee, Eun Gyo; Lee, Hongweon; Kim, Seon-Won; Choi, Eui-Sung

2012-06-01

Lactic acid fermentation of Jerusalem artichoke tuber was performed with strains of Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis prior to fermentation. Some strains of L. paracasei, notably KCTC13090 and KCTC13169, could ferment hot-water extract of Jerusalem artichoke tuber more efficiently compared with other Lactobacillus spp. such as L. casei type strain KCTC3109. The L. paracasei strains could utilize almost completely the fructo-oligosaccharides present in Jerusalem artichoke. Inulin-fermenting L. paracasei strains produced c.a. six times more lactic acid compared with L. casei KCTC3109. Direct lactic fermentation of Jerusalem artichoke tuber extract at 111.6g/L of sugar content with a supplement of 5 g/L of yeast extract by L. paracasei KCTC13169 in a 5L jar fermentor produced 92.5 ce:hsp sp="0.25"/>g/L of lactic acid with 16.8 g/L fructose equivalent remained unutilized in 72 h. The conversion efficiency of inulin-type sugars to lactic acid was 98% of the theoretical yield. Copyright © 2012 Elsevier Ltd. All rights reserved.

Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells

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Takuya Yamane; Tatsuji Sakamoto; Takenori Nakagaki; Yoshihisa Nakano

2018-01-01

The Japanese fermented beverage, homemade kefir, contains six lactic acid bacteria: Lactococcus. lactis subsp. Lactis, Lactococcus. lactis subsp. Cremoris, Lactococcus. Lactis subsp. Lactis biovar diacetylactis, Lactobacillus plantarum, Leuconostoc meseuteroides subsp. Cremoris and Lactobacillus casei. In this study, we found that a mixture of the six lactic acid bacteria from kefir increased the cytotoxicity of human natural killer KHYG-1 cells to human chronic myelogenous leukemia K562 cell...

Co-production of functional exopolysaccharides and lactic acid by Lactobacillus kefiranofaciens originated from fermented milk, kefir.

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Cheirsilp, Benjamas; Suksawang, Suwannee; Yeesang, Jarucha; Boonsawang, Piyarat

2018-01-01

Kefiran is a functional exopolysaccharide produced by Lactobacillus kefiranofaciens originated from kefir, traditional fermented milk in the Caucasian Mountains, Russia. Kefiran is attractive as thickeners, stabilizers, emulsifiers, gelling agents and also has antimicrobial and antitumor activity. However, the production costs of kefiran are still high mainly due to high cost of carbon and nitrogen sources. This study aimed to produce kefiran and its co-product, lactic acid, from low-cost industrial byproducts. Among the sources tested, whey lactose (at 2% sugar concentration) and spent yeast cells hydrolysate (at 6 g-nitrogen/L) gave the highest kefiran of 480 ± 21 mg/L along with lactic acid of 20.1 ± 0.2 g/L. The combination of these two sources and initial pH were optimized through Response Surface Methodology. With the optimized medium, L. kefiranofaciens produced more kefiran and lactic acid up to 635 ± 7 mg/L and 32.9 ± 0.7 g/L, respectively. When the pH was controlled to alleviate the inhibition from acidic pH, L. kefiranofaciens could consume all sugars and produced kefiran and lactic acid up to 1693 ± 29 mg/L and 87.49 ± 0.23 g/L, respectively. Moreover, the fed-batch fermentation with intermittent adding of whey lactose improved kefiran and lactic acid productions up to 2514 ± 93 mg/L and 135 ± 1.75 g/L, respectively. These results indicate the promising approach to economically produce kefiran and lactic acid from low-cost nutrient sources.

Complete Genome Sequence of a thermotolerant sporogenic lactic acid bacterium, Bacillus coagulans strain 36D1

Energy Technology Data Exchange (ETDEWEB)

Xie, Gary [Los Alamos National Laboratory (LANL); Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Chertkov, Olga [Los Alamos National Laboratory (LANL); Land, Miriam L [ORNL

2011-01-01

Bacillus coagulans is a ubiquitous soil bacterium that grows at 50-55 C and pH 5.0 and fer-ments various sugars that constitute plant biomass to L (+)-lactic acid. The ability of this sporogenic lactic acid bacterium to grow at 50-55 C and pH 5.0 makes this organism an attractive microbial biocatalyst for production of optically pure lactic acid at industrial scale not only from glucose derived from cellulose but also from xylose, a major constituent of hemi-cellulose. This bacterium is also considered as a potential probiotic. Complete genome squence of a representative strain, B. coagulans strain 36D1, is presented and discussed.

Trimethoprim/Sulfamethoxazole-Induced Severe Lactic Acidosis: A Case Report and Review of the Literature.

Science.gov (United States)

Bulathsinghala, Marie; Keefer, Kimberly; Van de Louw, Andry

2016-04-01

Propylene glycol (PG) is used as a solvent in numerous medications, including trimethoprim/sulfamethoxazole (TMP/SMX) and lorazepam, and is metabolized in the liver to lactic acid. Cases of lactic acidosis related to PG toxicity have been described and always involved large doses of benzodiazepines and PG. We present the first case of severe lactic acidosis after a 3-day course of TMP/SMX alone, involving allegedly safe amounts of PG.A 31-year-old female with neurofibromatosis and pilocytic astrocytoma, receiving temozolomide and steroids, was admitted to the intensive care unit for pneumonia and acute respiratory failure requiring intubation. Her initial hemodynamic and acid-base statuses were normal. She was treated with intravenous TMP/SMX for possible Pneumocystis jirovecii pneumonia and was successfully extubated on day 2. On day 3, she developed tachypnea and arterial blood gas analysis revealed a severe metabolic acidosis (pH 7.2, PCO2 19 mm Hg, bicarbonates 8 mEq/L) with anion gap of 25 mEq/L and lactate of 12.1 mmol/L. TMP/SMX was discontinued and the lactate decreased to 2.9 mmol/L within 24 hours while her plasma bicarbonates normalized, without additional intervention. The patient never developed hypotension or severe hypoxia, and her renal and liver functions were normal. No other cause for lactic acidosis was identified and it resolved after TMP/SMX cessation alone, suggesting PG toxicity.Although PG-related lactic acidosis is well recognized after large doses of lorazepam, clinicians should bear in mind that TMP/SMX contains PG as well and should suspect PG toxicity in patients developing unexplained metabolic acidosis while receiving TMP/SMX.

Characterization of airag collected in Ulaanbaatar, Mongolia with emphasis on isolated lactic acid bacteria

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Suk-Ho Choi

2016-03-01

Full Text Available Abstract Background Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares’ milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Methods Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Results Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10–3.36 % lactose, 1.44–2.33 % ethyl alcohol, 1.08–1.62 % lactic acid and 0.12–0.22 % acetic acid. Lactobacillus (L. helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Conclusion Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares’ milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

Biofuel and chemical production by recombinant microorganisms via fermentation of proteinaceous biomass

Science.gov (United States)

Liao, James C.; Cho, Kwang Myung; Yan, Yajun; Huo, Yixin

2016-03-15

Provided herein are metabolically modified microorganisms characterized by having an increased keto-acid flux when compared with the wild-type organism and comprising at least one polynucleotide encoding an enzyme that when expressed results in the production of a greater quantity of a chemical product when compared with the wild-type organism. The recombinant microorganisms are useful for producing a large number of chemical compositions from various nitrogen containing biomass compositions and other carbon sources. More specifically, provided herein are methods of producing alcohols, acetaldehyde, acetate, isobutyraldehyde, isobutyric acid, n-butyraldehyde, n-butyric acid, 2-methyl-1-butyraldehyde, 2-methyl-1-butyric acid, 3-methyl-1-butyraldehyde, 3-methyl-1-butyric acid, ammonia, ammonium, amino acids, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-1,4-butanediamine, isobutene, itaconate, acetoin, acetone, isobutene, 1,5-diaminopentane, L-lactic acid, D-lactic acid, shikimic acid, mevalonate, polyhydroxybutyrate (PHB), isoprenoids, fatty acids, homoalanine, 4-aminobutyric acid (GABA), succinic acid, malic acid, citric acid, adipic acid, p-hydroxy-cinnamic acid, tetrahydrofuran, 3-methyl-tetrahydrofuran, gamma-butyrolactone, pyrrolidinone, n-methylpyrrolidone, aspartic acid, lysine, cadeverine, 2-ketoadipic acid, and/or S-adenosyl-methionine (SAM) from a suitable nitrogen rich biomass.

Optimization of probiotic and lactic acid production by Lactobacillus plantarum in submerged bioreactor systems.

Science.gov (United States)

Brinques, Graziela Brusch; do Carmo Peralba, Maria; Ayub, Marco Antônio Záchia

2010-02-01

Biomass and lactic acid production by a Lactobacillus plantarum strain isolated from Serrano cheese, a microorganism traditionally used in foods and recognized as a potent probiotic, was optimized. Optimization procedures were carried out in submerged batch bioreactors using cheese whey as the main carbon source. Sequential experimental Plackett-Burman designs followed by central composite design (CCD) were used to assess the influence of temperature, pH, stirring, aeration rate, and concentrations of lactose, peptone, and yeast extract on biomass and lactic acid production. Results showed that temperature, pH, aeration rate, lactose, and peptone were the most influential variables for biomass formation. Under optimized conditions, the CCD for temperature and aeration rate showed that the model predicted maximal biomass production of 14.30 g l(-1) (dw) of L. plantarum. At the central point of the CCD, a biomass of 10.2 g l(-1) (dw), with conversion rates of 0.10 g of cell g(-1) lactose and 1.08 g lactic acid g(-1) lactose (w/w), was obtained. These results provide useful information about the optimal cultivation conditions for growing L. plantarum in batch bioreactors in order to boost biomass to be used as industrial probiotic and to obtain high yields of conversion of lactose to lactic acid.

GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

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AbstractThe need for the development of polymeric materials based on renewable resources has led to the development of poly(lactic acid) (PLA) which is being produced from a feedstock of corn rather than petroleum. The present study examines the permeation of nitrogen...

Validation of a hot water rinse and lactic acid spray in combination with scaling for treating hide-on carcasses to control biotype I strains of Escherichia coli used as surrogates for Shiga toxin-producing E. coli

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Scalding of hide-on bob veal carcasses with or without standard scalding chemical agents typically used for hogs, followed by an 82.2degreeC hot water wash and lactic acid spray (applied at ambient temperature) prior to chilling, was evaluated to determine its effectiveness in reducing the levels of...

Antimicrobial potential of triticale stillage after lactic acid fermentation with Lactobacillus fermentum PL-1

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Kujundžić Žužana

2013-01-01

Full Text Available This study is concerned with the testing of antimicrobial activity of triticale stillage obtained after lactic fermentation by Lactobacillus fermentum PL-1. The antimicrobial tests were performed using the disc-diffusion and agar well diffusion methods. It was found that fermented triticale stillage after lactic acid fermentation exhibited an inhibitory effect towards tested Gram positive and Gram negative bacteria: Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa, Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis. The triticale stillage without addition of CaCO3 before fermentation showed a stronger antimicrobial effect in comparison with the triticale stillage with added CaCO3. Triticale stillage after lactic acid fermentation did not show any antifungal effect on the growth of tested moulds (Alternaria alternata, Aspergillus versicolor, Penicillium brevicompactum, and Fusarium subglutinans. [Projekat Ministarstva nauke Republike Srbije, br. TR-31017

Mutation in mitochondrial complex IV subunit COX5A causes pulmonary arterial hypertension, lactic acidemia, and failure to thrive.

Science.gov (United States)

Baertling, Fabian; Al-Murshedi, Fathiya; Sánchez-Caballero, Laura; Al-Senaidi, Khalfan; Joshi, Niranjan P; Venselaar, Hanka; van den Brand, Mariël Am; Nijtmans, Leo Gj; Rodenburg, Richard Jt

2017-06-01

COX5A is a nuclear-encoded subunit of mitochondrial respiratory chain complex IV (cytochrome c oxidase). We present patients with a homozygous pathogenic variant in the COX5A gene. Clinical details of two affected siblings suffering from early-onset pulmonary arterial hypertension, lactic acidemia, failure to thrive, and isolated complex IV deficiency are presented. We show that the variant lies within the evolutionarily conserved COX5A/COX4 interface domain, suggesting that it alters the interaction between these two subunits during complex IV biogenesis. In patient skin fibroblasts, the enzymatic activity and protein levels of complex IV and several of its subunits are reduced. Lentiviral complementation rescues complex IV deficiency. The monomeric COX1 assembly intermediate accumulates demonstrating a function of COX5A in complex IV biogenesis. A potential therapeutic lead is demonstrated by showing that copper supplementation leads to partial rescue of complex IV deficiency in patient fibroblasts. © 2017 Wiley Periodicals, Inc.

Highly efficient production of optically pure l-lactic acid from corn stover hydrolysate by thermophilic Bacillus coagulans.

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Ma, Kedong; Hu, Guoquan; Pan, Liwei; Wang, Zichao; Zhou, Yi; Wang, Yanwei; Ruan, Zhiyong; He, Mingxiong

2016-11-01

A thermophilic strain Bacillus coagulans (NBRC 12714) was employed to produce l-lactic acid from corn stover hydrolysate in membrane integrated continuous fermentation. The strain NBRC 12714 metabolized glucose and xylose by the Embden-Meyerhof-Parnas pathway (EMP) and the pentose phosphate pathway (PPP), producing l-lactic acid with optical purity >99.5%. The overall l-lactic acid titer of 92g/l with a yield of 0.91g/g and a productivity of 13.8g/l/h were achieved at a dilution rate of 0.15h(-1). The productivity obtained was 1.6-fold than that of conventional continuous fermentation without cell recycling, and also was the highest among the relevant studies ever reported. These results indicated that the process developed had great potential for economical industrial production of l-lactic acid from lignocellulosic biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid

Science.gov (United States)

Liguori, Rossana; Soccol, Carlos Ricardo; Vandenberghe, Luciana Porto de Souza; Woiciechowski, Adenise Lorenci; Ionata, Elena; Marcolongo, Loredana; Faraco, Vincenza

2015-01-01

Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source. PMID:26640784

Biodiversity and evolution of lactic acid bacteria in deferent periods ...

African Journals Online (AJOL)

f e c

2013-04-03

Apr 3, 2013 ... Key words: Lactic acid bacteria, identification, silage, sorghum, evolution, amylolytic, .... milk was checked which indicates the presence of LAB (Sengun et ..... pH, temperature and salinity cannot be used as reference.

Biotechnological conversion of spent coffee grounds into lactic acid.

Science.gov (United States)

Hudeckova, H; Neureiter, M; Obruca, S; Frühauf, S; Marova, I

2018-04-01

This work investigates the potential bioconversion of spent coffee grounds (SCG) into lactic acid (LA). SCG were hydrolysed by a combination of dilute acid treatment and subsequent application of cellulase. The SCG hydrolysate contained a considerable amount of reducing sugars (9·02 ± 0·03 g l -1 , glucose; 26·49 ± 0·10 g l -1 galactose and 2·81 ± 0·07 g l -1 arabinose) and it was used as a substrate for culturing several lactic acid bacteria (LAB) and LA-producing Bacillus coagulans. Among the screened micro-organisms, Lactobacillus rhamnosus CCM 1825 was identified as the most promising producer of LA on a SCG hydrolysate. Despite the inhibitory effect exerted by furfural and phenolic compounds in the medium, reasonably high LA concentrations (25·69 ± 1·45 g l -1 ) and yields (98%) were gained. Therefore, it could be demonstrated that SCG is a promising raw material for the production of LA and could serve as a feedstock for the sustainable large-scale production of LA. Spent coffee grounds (SCG) represent solid waste generated in millions of tonnes by coffee-processing industries. Their disposal represents a serious environmental problem; however, SCG could be valorized within a biorefinery concept yielding various valuable products. Herein, we suggest that SCG can be used as a complex carbon source for the lactic acid production. © 2018 The Society for Applied Microbiology.

Study of Chemical Intermediates by Means of ATR-IR Spectroscopy and Hybrid Hard- and Soft-Modelling Multivariate Curve Resolution-Alternating Least Squares

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Junxiu Ma

2017-01-01

Full Text Available 3,5-Diamino-1,2,4-triazole (DAT became a significant energetic materials intermediate, and the study of its reaction mechanism has fundamental significance in chemistry. The aim of this study is to investigate the ability of online attenuated total reflection infrared (ATR-IR spectroscopy combined with the novel approach of hybrid hard- and soft-modelling multivariate curve resolution-alternating least squares (HS-MCR analysis to monitor and detect changes in structural properties of compound during 3,5-diamino-1,2,4-triazole (DAT synthesis processes. The subspace comparison method (SCM was used to obtain the principal components number, and then the pure IR spectra of each substance were obtained by independent component analysis (ICA and HS-MCR. The extent of rotation ambiguity was estimated from the band boundaries of feasible solutions calculated using the MCR-BANDS procedure. There were five principal components including two intermediates in the process in the results. The reaction rate constants of DAT formation reaction were also obtained by HS-MCR. HS-MCR was used to analyze spectroscopy data in chemical synthesis process, which not only increase the information domain but also reduce the ambiguities of the obtained results. This study provides the theoretical basis for the optimization of synthesis process and technology of energetic materials and provides a strong technical support of research and development of energy material with extraordinary damage effects.

Study of Chemical Intermediates by Means of ATR-IR Spectroscopy and Hybrid Hard- and Soft-Modelling Multivariate Curve Resolution-Alternating Least Squares.

Science.gov (United States)

Ma, Junxiu; Qi, Juan; Gao, Xinyu; Yan, Chunhua; Zhang, Tianlong; Tang, Hongsheng; Li, Hua

2017-01-01

3,5-Diamino-1,2,4-triazole (DAT) became a significant energetic materials intermediate, and the study of its reaction mechanism has fundamental significance in chemistry. The aim of this study is to investigate the ability of online attenuated total reflection infrared (ATR-IR) spectroscopy combined with the novel approach of hybrid hard- and soft-modelling multivariate curve resolution-alternating least squares (HS-MCR) analysis to monitor and detect changes in structural properties of compound during 3,5-diamino-1,2,4-triazole (DAT) synthesis processes. The subspace comparison method (SCM) was used to obtain the principal components number, and then the pure IR spectra of each substance were obtained by independent component analysis (ICA) and HS-MCR. The extent of rotation ambiguity was estimated from the band boundaries of feasible solutions calculated using the MCR-BANDS procedure. There were five principal components including two intermediates in the process in the results. The reaction rate constants of DAT formation reaction were also obtained by HS-MCR. HS-MCR was used to analyze spectroscopy data in chemical synthesis process, which not only increase the information domain but also reduce the ambiguities of the obtained results. This study provides the theoretical basis for the optimization of synthesis process and technology of energetic materials and provides a strong technical support of research and development of energy material with extraordinary damage effects.

Isovector couplings for nucleon charge-exchange reactions at intermediate energies

International Nuclear Information System (INIS)

Love, W.G.; Nakayama, K.; Franey, M.A.

1987-01-01

The isovector parts of the effective nucleon-nucleon interaction are studied by examination of the reaction /sup 14/C(p,n) at intermediate energies near zero momentum transfer with use of recently developed G-matrix and free--t-matrix interactions. The spin-independent coupling (V/sub tau/) exhibits a strong energy and density dependence which, in the case of the G matrix based on the Bonn potential, significantly improves the agreement between calculated values of chemical bondV/sub σ//sub tau//V/sub tau/chemical bond 2 at q = 0 and those recently extracted from the reaction /sup 14/C

Feasibility of converting lactic acid to ethanol in food waste fermentation by immobilized lactate oxidase

International Nuclear Information System (INIS)

Ma, Hong-zhi; Xing, Yi; Yu, Miao; Wang, Qunhui

2014-01-01

Highlights: • Residue lactic acid in food waste could be converted to pyruvic acid. • Calcium alginate immobilized the lactate oxidase with high pH and thermal stability. • Immobilized enzyme could convert 70% lactic acid to pyruvic acid. • Ethanol yield could be increased by 20% with lactate oxidase added. - Abstract: Adoption of lactic acid bacteria (LAB) into ethanol fermentation from food waste can replace the sterilization process. However, LAB inoculation will convert part of the substrate into lactic acid (LA), not ethanol. This study adopted lactate oxidase to convert the produced LA to pyruvate, and then ethanol fermentation was carried out. The immobilization enzyme was utilized, and corresponding optimum conditions were determined. Results showed that calcium alginate could successfully immobilize the enzyme and improve pH and thermal stability. The optimum pH and temperature were 6.2 and 55 °C, respectively. The utilization of immobilized enzyme with catalytic time of 5 h could convert 70% LA to pyruvate, and the addition of enzyme increased the ethanol yield by 20% more than that of the control. The process could be applied in food waste storage and can help in reducing carbon source consumption

In vitro Degradation of Butanediamine-Grafted Poly(DL-Lactic acids)

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The degradation of butanediamine-grafted poly(DL-lactic acid) polymers (BDPLAs) in vitro together with PDLLA and maleic anhydride-grafted poly(DL-lactic acid) polymers (MPLAs) was investigated by observation of the changes of the pH value of incubation media, and weight loss ratio during degradation duration of 12 weeks. The results reveal that the acidity of PDLLA degradation products was weakened or neutralized by grafting butanediamine onto PDLLA. A uniform degradation of BDPLAs was observed in comparison with an acidity-induced auto-accelerating degradation featured by PDLLA and MPLAs. The biodegradation behaviors of BDPLAs can be adjusted by controlling the content of BDA. BDPLAs might be a new derivative of PDLLA-based biodegradable materials for medical applications without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as that of PDLLA.

Lactic acid induces aberrant amyloid precursor protein processing by promoting its interaction with endoplasmic reticulum chaperone proteins.

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Yiwen Xiang

Full Text Available BACKGROUND: Lactic acid, a natural by-product of glycolysis, is produced at excess levels in response to impaired mitochondrial function, high-energy demand, and low oxygen availability. The enzyme involved in the production of β-amyloid peptide (Aβ of Alzheimer's disease, BACE1, functions optimally at lower pH, which led us to investigate a potential role of lactic acid in the processing of amyloid precursor protein (APP. METHODOLOGY/PRINCIPAL FINDINGS: Lactic acid increased levels of Aβ40 and 42, as measured by ELISA, in culture medium of human neuroblastoma cells (SH-SY5Y, whereas it decreased APP metabolites, such as sAPPα. In cell lysates, APP levels were increased and APP was found to interact with ER-chaperones in a perinuclear region, as determined by co-immunoprecipitation and fluorescence microscopy studies. Lactic acid had only a very modest effect on cellular pH, did increase the levels of ER chaperones Grp78 and Grp94 and led to APP aggregate formation reminiscent of aggresomes. CONCLUSIONS/SIGNIFICANCE: These findings suggest that sustained elevations in lactic acid levels could be a risk factor in amyloidogenesis related to Alzheimer's disease through enhanced APP interaction with ER chaperone proteins and aberrant APP processing leading to increased generation of amyloid peptides and APP aggregates.

Chemical yield determination for 59Ni, 63Ni and 56Fe in low and intermediate nuclear wastes by ICP-AES

International Nuclear Information System (INIS)

Franco, Milton B.; Santos Neto, Francisco C. dos; Reis Junior, Aluisio S.; Temba, Eliane S.C.; Monteiro, Roberto P.G.

2011-01-01

Iron and nickel are constituents of a wide range of metallic materials used in nuclear reactor construction and their corresponding activation products are often encountered in reactor-derived solid low and intermediate-level wastes. The most significant radioisotopes of iron and nickel, in terms of quantity and half life, are 55 Fe (t 1/2 =2.73y), 59 Ni (t 1/2 =7.6x10 4 y) and 63 Ni (t 1/2 =10 2 y) and they are activation products of stable iron and nickel. 59 Ni is an X-ray - emitting and 55 Fe and 63 Ni are β-particle-emitting radionuclides and so they are radionuclides of interest for the performance of assessment studies of waste storage or disposal. For their determination in the radioactive wastes is necessary to know the chemical yield for the radiochemical separation procedures prior analytical measurements. In this work Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) technique was used for this aim. Total nickel and iron in waste samples from nuclear power plants were determined before and after the radiochemical separation at specific wavelengths, 231.604 nm and 259.940 nm respectively. The chemical yields for nickel and iron recovery were around 82 % for iron and 59 % for nickel according the analytical methodology adopted. (author)

Lactic Acid Bacterial Vaginosis among Outpatients in Addis Ababa ...

African Journals Online (AJOL)

Background: Bacterial vaginosis (BV) is a polymicrobial syndrome in which a decrease in vaginal acidity and concentration of lactobacilli is accompanied by an increase of other pathogenic micro-organisms. The distribution of lactic acid bacteria in vaginal environment of Ethiopian women has not been documented.

Valorization of Agri-Food Waste via Fermentation: Production of l-lactic Acid as a Building Block for the Synthesis of Biopolymers

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Giovanni Dedenaro

2016-11-01

Full Text Available Global interest towards lactic acid production has recently significantly increased because lactic acid can be used as raw material for the production of polylactic acid (PLA, a polymer used in biodegradable plastics for its special, environmentally-friendly properties. However, the high production costs have hindered the large-scale application of PLA due to the high price of lactic acid. Here we evaluated the potential of pear pomace and ricotta cheese whey (RCW as a low-cost source of nutrients for lactic acid fermentation of Lactobacillus casei and Lactobacillus farciminis in microaerophilic conditions and mild sterility. After an initial lab-scale screening of 19 lactic acid bacteria (LAB strains to select the highest producer of lactic acid, we reported the 1L-batch scale-up to test process efficiency and productivity of the most promising LAB strains. Batch fermentation of a 25:75 mixture of pear pomace and RCW, respectively, reached an overall yield factor of 90% and a volumetric productivity of 0.42 g/L·h.

Chemical substructure analysis in toxicology

Energy Technology Data Exchange (ETDEWEB)

Beauchamp, R.O. Jr. [Center for Information on Toxicology and Environment, Raleigh, NC (United States)

1990-12-31

A preliminary examination of chemical-substructure analysis (CSA) demonstrates the effective use of the Chemical Abstracts compound connectivity file in conjunction with the bibliographic file for relating chemical structures to biological activity. The importance of considering the role of metabolic intermediates under a variety of conditions is illustrated, suggesting structures that should be examined that may exhibit potential activity. This CSA technique, which utilizes existing large files accessible with online personal computers, is recommended for use as another tool in examining chemicals in drugs. 2 refs., 4 figs.

Effect of sodium bicarbonate administration on mortality in patients with lactic acidosis: a retrospective analysis.

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Hyun Jeong Kim

Full Text Available BACKGROUND: Lactic acidosis is a common cause of high anion gap metabolic acidosis. Sodium bicarbonate may be considered for an arterial pH <7.15 but paradoxically depresses cardiac performance and exacerbates acidosis by enhancing lactate production. This study aimed to evaluate the cause and mortality rate of lactic acidosis and to investigate the effect of factors, including sodium bicarbonate use, on death. METHODS: We conducted a single center analysis from May 2011 through April 2012. We retrospectively analyzed 103 patients with lactic acidosis among 207 patients with metabolic acidosis. We used SOFA and APACHE II as severity scores to estimate illness severity. Multivariate logistic regression analysis and Cox regression analysis models were used to identify factors that affect mortality. RESULTS: Of the 103 patients with a mean age of 66.1±11.4 years, eighty-three patients (80.6% died from sepsis (61.4%, hepatic failure, cardiogenic shock and other causes. The percentage of sodium bicarbonate administration (p = 0.006, catecholamine use, ventilator care and male gender were higher in the non-survival group than the survival group. The non-survival group had significantly higher initial and follow-up lactic acid levels, lower initial albumin, higher SOFA scores and APACHE II scores than the survival group. The mortality rate was significantly higher in patients who received sodium bicarbonate. Sodium bicarbonate administration (p = 0.016 was associated with higher mortality. Independent factors that affected mortality were SOFA score (Exp (B = 1.72, 95% CI = 1.12-2.63, p = 0.013 and sodium bicarbonate administration (Exp (B = 6.27, 95% CI = 1.10-35.78, p = 0.039. CONCLUSIONS: Lactic acidosis, which has a high mortality rate, should be evaluated in patients with metabolic acidosis. In addition, sodium bicarbonate should be prescribed with caution in the case of lactic acidosis because sodium bicarbonate

Complete Genome Sequence of a thermotolerant sporogenic lactic acid bacterium, Bacillus coagulans strain 36D1