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Sample records for lactic acid sting

  1. 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 ...

  2. Take a Bite Out of Mosquito Stings

    Science.gov (United States)

    ... mosquito stings Share | Take a Bite Out of Mosquito Stings This article has been reviewed by Thanai ... lactic acid and carbon dioxide attract the female mosquito to skin. She inserts the tip of her ...

  3. 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 perspec

  4. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    OpenAIRE

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  5. [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.

  6. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    Directory of Open Access Journals (Sweden)

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  7. 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...

  8. Engineering robust lactic acid bacteria

    NARCIS (Netherlands)

    Bron, P.A.; Bokhorst-van de Veen, van H.; Wels, M.; Kleerebezem, M.

    2011-01-01

    For centuries, lactic acid bacteria (LAB) have been industrially exploited as starter cultures in the fermentation of foods and feeds for their spoilage-preventing and flavor-enhancing characteristics. More recently, the health-promoting effects of LAB on the consumer have been widely acknowledged,

  9. Lactic acid oligomers (OLAs) as prodrug moieties.

    Science.gov (United States)

    Kruse, J; Lachmann, B; Lauer, R; Eppacher, S; Noe, C R

    2013-02-01

    In this paper we propose the use of lactic acid oligomers (OLAs) as prodrug moieties. Two synthetic approaches are presented, on the one hand a non selective oligomerisation of lactic acid and on the other hand a block synthesis to tetramers of lactic acid. Dimers of lactic acid were investigated with respect to their plasma stability and their adsorption to albumine. Ibuprofen was chosen as the first drug for OLAylation. The ester 19 of LA(1)-ibuprofen was evaluated with respect to the degradation to human plasma and the adsorption to albumine. All results indicate that lactic acid oligomers are promising prodrug moieties.

  10. Amino acids analysis during lactic acid fermentation by single strain ...

    African Journals Online (AJOL)

    SAM

    2014-07-09

    Jul 9, 2014 ... of the three LAB strains to utilize amino acids for growth and lactic acid production were employed to ... Lactic acid bacteria (LAB), which are used for the ..... and characterization of potential probiotic lactobacilli from pig feces.

  11. 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, 598-82-3; l-isomer, 79-33-4; d-isomer, 10326-41-7), the chemical 2-hydroxypropanoic acid, occurs...

  12. 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...

  13. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Directory of Open Access Journals (Sweden)

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  14. Lactic Acid Bacteria in the Gut

    NARCIS (Netherlands)

    Stolaki, M.; Vos, de W.M.; Kleerebezem, M.; Zoetendal, E.G.

    2012-01-01

    From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped,

  15. 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...

  16. Lactic Acid Bacteria in the Gut

    NARCIS (Netherlands)

    Stolaki, M.; Vos, de W.M.; Kleerebezem, M.; Zoetendal, E.G.

    2012-01-01

    From all bacterial groups, the lactic acid bacteria (LAB) are probably the group of bacteria that is most associated with human lifestyle. The term LAB mainly refers to the ability of these organisms to convert sugars to lactic acid. The LAB comprise non-sporing, aerotolerant, coccus or rod-shaped,

  17. Energy transduction in lactic acid bacteria

    NARCIS (Netherlands)

    Poolman, Bert

    In the discovery of some general principles of energy transduction, lactic acid bacteria have played an important role. In this review, the energy transducing processes of lactic acid bacteria are discussed with the emphasis on the major developments of the past 5 years. This work not only includes

  18. 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 bact

  19. Lactic acid fermentation-aided biomass conversion

    Energy Technology Data Exchange (ETDEWEB)

    Martin, A.M. [Memorial Univ. of Newfoundland, St. John`s, NF (Canada). Dept. of Biochemistry

    1996-09-01

    The preservation of fisheries biomass by lactic acid fermentation is discussed. This method is favourably compared to acid ensiling and fish meal production in terms of safety considerations, energy requirements, simplicity of process and product quality. (Author)

  20. Lactic Acid Bacteria in Health and Disease

    African Journals Online (AJOL)

    reports demonstrating the health promoting effects of ... therapy. In 1908, élie Metchinkoff, proposed that the acid-producing organisms (lactic acid bacteria) ... Phage resistance aids in .... In a study conducted [29] in children aged 3 it was found.

  1. Genetics of Lactic Acid Bacteria

    Science.gov (United States)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  2. Quorum sensing mechanism in lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Hatice Yılmaz - Yıldıran

    2015-04-01

    and detection occurs as a consecution it is hard to understand their QS mechanism. In this review, connection between QS mechanism and some characteristics of lactic acid bacteria are evaluated such as concordance with its host, inhibition of pathogen development and colonization in gastrointestinal system, bacteriocin production, acid and bile resistance, adhesion to epithelium cells. Understanding QS mechanism of lactic acid bacteria will be useful to design metabiotics which is defined as novel probiotics.

  3. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T.; Altermann, E.; Arigoni, F.; Bolotin, A.; Breidt, F.; Broadbent, J.; Cano, R.; Chaillou, S.; Deutscher, J.; Gasson, M.; Guchte, van de M.; Guzzo, J.; Hartke, A.; Hawkins, T.; Hols, P.; Hutkins, R.; Kleerebezem, M.; Kok, J.; Kuipers, O.; Lubbers, M.; Maguin, E.; McKay, L.; Mills, D.; Nauta, A.; Overbeek, R.; Pel, H.; Pridmore, D.; Saier, M.; Sinderen, van D.; Sorokin, A.; Steele, J.; O'Sullivan, D.; Vos, de W.; Weimer, B.; Zagorec, M.; Siezen, R.

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in

  4. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T; Altermann, E; Arigoni, F; Bolotin, A; Breidt, F; Broadbent, J; Cano, R; Chaillou, S; Deutscher, J; Gasson, M; van de Guchte, M; Guzzo, J; Hartke, A; Hawkins, T; Hols, P; Hutkins, R; Kleerebezem, M; Kok, J; Kuipers, O; Maguin, E; McKay, L; Mills, D; Nauta, A; Overbeek, R; Pel, H; Pridmore, D; Saier, M; van Sinderen, D; Sorokin, A; Steele, J; O'Sullivan, D; de Vos, W; Weimer, B; Zagorec, M; Siezen, R

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in

  5. 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...

  6. 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.

  7. The proteolytic system of lactic acid bacteria.

    Science.gov (United States)

    Mayo, B

    1993-12-01

    Lactic acid bacteria are widely used throughout the world, empirically or deliberately, in the manufacturing of several food and feed stuffs, including milk products (such as cheese, butter, yoghurt, buttermilk, etc.), fermented vegetables (pickles, olives and sauerkraut), sausages, sourdough bread and silage, due to their ability to convert sugars into lactic acid. Of these, dairy products are of outstanding economic importance. Starter cultures used in the dairy industry are mixtures of carefully selected lactic acid bacteria which are added to the milk to fulfil the desired fermentation. Dairy starter cultures must reach high densities in milk in order to produce lactic acid at the required rates for manufacturing. Under these conditions, amino acids supply becomes limitant due to their scarce concentration in milk and to the auxotrophies shown by many starter bacteria. This implies the necessity of a proteolytic system, able to degrade the most abundant protein in milk, casein, into assimilable amino acids and peptides. Casein degradation and utilization require the concerted action of proteinases, peptidases and amino acid and peptide uptake systems. This whole set of enzymes constitutes the proteolytic system. In this article an overview of the recent biochemical and genetic data on the proteolytic system of lactic acid bacteria will be presented.

  8. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    1988-01-01

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  9. Genetics of proteinases of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan; Venema, Gerhardus

    Because it is essential for good growth with concomitant rapid acid production, and for the production of flavorous peptides and amino acids, the proteolytic ability of lactic acid bacteria is of crucial importance for reliable dairy product quality. In view of this importance, considerable research

  10. 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.

  11. Effects of a honeybee sting on the serum free amino acid profile in humans.

    Directory of Open Access Journals (Sweden)

    Jan Matysiak

    Full Text Available The aim of this study was to assess the response to a honeybee venom by analyzing serum levels of 34 free amino acids. Another goal of this study was to apply complex analytic-bioinformatic-clinical strategy based on up-to-date achievements of mass spectrometry in metabolomic profiling. The amino acid profiles were determined using hybrid triple quadrupole/linear ion trap mass spectrometer coupled with a liquid chromatography instrument. Serum samples were collected from 27 beekeepers within 3 hours after they were stung and after a minimum of 6 weeks following the last sting. The differences in amino acid profiles were evaluated using MetaboAnalyst and ROCCET web portals. Chemometric tests showed statistically significant differences in the levels of L-glutamine (Gln, L-glutamic acid (Glu, L-methionine (Met and 3-methyl-L-histidine (3MHis between the two analyzed groups of serum samples. Gln and Glu appeared to be the most important metabolites for distinguishing the beekeepers tested shortly after a bee sting from those tested at least 6 weeks later. The role of some amino acids in the response of an organism to the honeybee sting was also discussed. This study indicated that proposed methodology may allow to identify the individuals just after the sting and those who were stung at least 6 weeks earlier. The results we obtained will contribute to better understanding of the human body response to the honeybee sting.

  12. 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:

  13. 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.

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

    African Journals Online (AJOL)

    African Journal of Biotechnology ... Fermentation of various foods by lactic acid bacteria (LAB) is one of the oldest forms of ... scientific research about lactic acid bacteria as probiotics and their bacteriocins for healthy nutrition of fermented food.

  15. 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...

  16. Lactic acid bacterial cell factories for gamma-aminobutyric acid.

    Science.gov (United States)

    Li, Haixing; Cao, Yusheng

    2010-11-01

    Gamma-aminobutyric acid is a non-protein amino acid that is widely present in organisms. Several important physiological functions of gamma-aminobutyric acid have been characterized, such as neurotransmission, induction of hypotension, diuretic effects, and tranquilizer effects. Many microorganisms can produce gamma-aminobutyric acid including bacteria, fungi and yeasts. Among them, gamma-aminobutyric acid-producing lactic acid bacteria have been a focus of research in recent years, because lactic acid bacteria possess special physiological activities and are generally regarded as safe. They have been extensively used in food industry. The production of lactic acid bacterial gamma-aminobutyric acid is safe and eco-friendly, and this provides the possibility of production of new naturally fermented health-oriented products enriched in gamma-aminobutyric acid. The gamma-aminobutyric acid-producing species of lactic acid bacteria and their isolation sources, the methods for screening of the strains and increasing their production, the enzymatic properties of glutamate decarboxylases and the relative fundamental research are reviewed in this article. And the potential applications of gamma-aminobutyric acid-producing lactic acid bacteria were also referred to.

  17. Anchoring of proteins to lactic acid bacteria

    NARCIS (Netherlands)

    Leenhouts, K; Buist, Girbe; Kok, Jan

    1999-01-01

    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been exp

  18. Why engineering lactic acid bacteria for biobutanol

    Science.gov (United States)

    The Gram-positive Lactic acid bacteria (LAB) are considered attractive biocatalysts for biomass to biofuels for several reasons. They have GRAS (Generally Recognized As Safe) status that are acceptable in food, feed, and medical applications. LAB are fermentative: selected strains are capable of f...

  19. 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) sy

  20. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

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

    2005-01-01

    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

  1. 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

  2. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T; Altermann, E; Arigoni, F; Bolotin, A; Breidt, F; Broadbent, J; Cano, R; Chaillou, S; Deutscher, J; Gasson, M; van de Guchte, M; Guzzo, J; Hartke, A; Hawkins, T; Hols, P; Hutkins, R; Kleerebezem, M; Kok, J; Kuipers, O; Maguin, E; McKay, L; Mills, D; Nauta, A; Overbeek, R; Pel, H; Pridmore, D; Saier, M; van Sinderen, D; Sorokin, A; Steele, J; O'Sullivan, D; de Vos, W; Weimer, B; Zagorec, M; Siezen, R

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, environmental habitat, and its role in ferment

  3. Discovering lactic acid bacteria by genomics

    NARCIS (Netherlands)

    Klaenhammer, T.; Altermann, E.; Arigoni, F.; Bolotin, A.; Breidt, F.; Broadbent, J.; Cano, R.; Chaillou, S.; Deutscher, J.; Gasson, M.; Guchte, van de M.; Guzzo, J.; Hartke, A.; Hawkins, T.; Hols, P.; Hutkins, R.; Kleerebezem, M.; Kok, J.; Kuipers, O.; Lubbers, M.; Maguin, E.; McKay, L.; Mills, D.; Nauta, A.; Overbeek, R.; Pel, H.; Pridmore, D.; Saier, M.; Sinderen, van D.; Sorokin, A.; Steele, J.; O'Sullivan, D.; Vos, de W.; Weimer, B.; Zagorec, M.; Siezen, R.

    2002-01-01

    This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in fermenta

  4. 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

  5. Multidrug transporters in lactic acid bacteria

    NARCIS (Netherlands)

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

    2005-01-01

    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

  6. 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 proteo

  7. Anchoring of proteins to lactic acid bacteria

    NARCIS (Netherlands)

    Leenhouts, K; Buist, Girbe; Kok, Jan

    1999-01-01

    The anchoring of proteins to the cell surface of lactic acid bacteria (LAB) using genetic techniques is an exciting and emerging research area that holds great promise for a wide variety of biotechnological applications. This paper reviews five different types of anchoring domains that have been exp

  8. Precision genome engineering in lactic acid bacteria.

    Science.gov (United States)

    van Pijkeren, Jan Peter; Britton, Robert A

    2014-08-29

    Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety.

  9. Making More of Milk Sugar by Engineering Lactic Acid Bacteria

    NARCIS (Netherlands)

    Vos, Willem M. de; Hols, Pascal; Kranenburg, Richard van; Luesink, Evert; Kuipers, Oscar P.; Oost, John van der; Kleerebezem, Michiel; Hugenholtz, Jeroen

    1998-01-01

    By exploiting their genetic and metabolic capacity, lactic acid bacteria can be used to generate a variety of products from milk sugar lactose other than the archetypical lactic acid. This review will outline the different genetic and metabolic engineering strategies that can be applied to lactic ac

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

    NARCIS (Netherlands)

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

    1958-01-01

    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.

  11. Making More of Milk Sugar by Engineering Lactic Acid Bacteria

    NARCIS (Netherlands)

    Vos, Willem M. de; Hols, Pascal; Kranenburg, Richard van; Luesink, Evert; Kuipers, Oscar P.; Oost, John van der; Kleerebezem, Michiel; Hugenholtz, Jeroen

    1998-01-01

    By exploiting their genetic and metabolic capacity, lactic acid bacteria can be used to generate a variety of products from milk sugar lactose other than the archetypical lactic acid. This review will outline the different genetic and metabolic engineering strategies that can be applied to lactic

  12. Corrosion Behavior of Titanium in Artificial Saliva by Lactic Acid

    Directory of Open Access Journals (Sweden)

    Qing Qu

    2014-07-01

    Full Text Available As one of the main products produced by oral microorganisms, the role of lactic acid in the corrosion of titanium is very important. In this study, the corrosion behavior of titanium in artificial saliva with and without lactic acid were investigated by open-circuit potentials (OCPs, polarization curves and electrochemical impedance spectroscopy (EIS. OCP firstly increased with the amount of lactic acid from 0 to 3.2 g/L and then tended to decrease from 3.2 to 5.0 g/L. The corrosion of titanium was distinctly affected by lactic acid, and the corrosion rate increased with increasing the amount of lactic acid. At each concentration of lactic acid, the corrosion rate clearly increased with increasing the immersing time. Results of scanning electron microscopy (SEM also indicated that lactic acid accelerated the pitting corrosion in artificial saliva. A probable mechanism was also proposed to explain the experimental results.

  13. Hydrogen production by fermentation using acetic acid and lactic acid.

    Science.gov (United States)

    Matsumoto, Mitsufumi; Nishimura, Yasuhiko

    2007-03-01

    Microbial hydrogen production from sho-chu post-distillation slurry solution (slurry solution) containing large amounts of organic acids was investigated. The highest hydrogen producer, Clostridium diolis JPCC H-3, was isolated from natural environment and produced hydrogen at 6.03+/-0.15 ml from 5 ml slurry solution in 30 h. Interestingly, the concentration of acetic acid and lactic acid in the slurry solution decreased during hydrogen production. The substrates for hydrogen production by C. diolis JPCC H-3, in particular organic acids, were investigated in an artificial medium. No hydrogen was produced from acetic acid, propionic acid, succinic acid, or citric acid on their own. Hydrogen and butyric acid were produced from a mixture of acetic acid and lactic acid, showing that C. diolis. JPCC H-3 could produce hydrogen from acetic acid and lactic acid. Furthermore, calculation of the Gibbs free energy strongly suggests that this reaction would proceed. In this paper, we describe for the first time microbial hydrogen production from acetic acid and lactic acid by fermentation.

  14. [Bacteriocins produced by lactic acid bacteria].

    Science.gov (United States)

    Bilková, Andrea; Sepova, Hana Kinová; Bilka, Frantisek; Balázová, Andrea

    2011-04-01

    Lactic acid bacteria comprise several genera of gram-positive bacteria that are known for the production of structurally different antimicrobial substances. Among them, bacteriocins are nowadays in the centre of scientific interest. Bacteriocins, proteinaceous antimicrobial substances, are produced ribosomally and have usually a narrow spectrum of bacterial growth inhibition. According to their structure and the target of their activity, they are divided into four classes, although there are some suggestions for a renewed classification. The most interesting and usable class are lantibiotics. They comprise the most widely commercially used and well examined bacteriocin, nisin. The non-pathogenic character of lactic acid bacteria is advantageous for using their bacteriocins in food preservation as well as in feed supplements or in veterinary medicine.

  15. 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.

  16. Technological and economic potential of poly(lactic acid) and lactic acid derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.; Bonsignore, P.; Moon, S.H.; Frank, J.R.

    1993-10-01

    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}40,000 tons/yr) used in a wide range of food processing and industrial applications. lactic acid h,as the potential of becoming a very large volume, commodity-chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, plant growth regulators, environmentally friendly ``green`` solvents, and specially chemical intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of tactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. In this paper, the recent technical advances in tactic and polylactic acid processes are discussed. The economic potential and manufacturing cost estimates of several products and process options are presented. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.

  17. Recent advances in lactic acid production by microbial fermentation processes.

    Science.gov (United States)

    Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Sonomoto, Kenji

    2013-11-01

    Fermentative production of optically pure lactic acid has roused interest among researchers in recent years due to its high potential for applications in a wide range of fields. More specifically, the sharp increase in manufacturing of biodegradable polylactic acid (PLA) materials, green alternatives to petroleum-derived plastics, has significantly increased the global interest in lactic acid production. However, higher production costs have hindered the large-scale application of PLA because of the high price of lactic acid. Therefore, reduction of lactic acid production cost through utilization of inexpensive substrates and improvement of lactic acid production and productivity has become an important goal. Various methods have been employed for enhanced lactic acid production, including several bioprocess techniques facilitated by wild-type and/or engineered microbes. In this review, we will discuss lactic acid producers with relation to their fermentation characteristics and metabolism. Inexpensive fermentative substrates, such as dairy products, food and agro-industrial wastes, glycerol, and algal biomass alternatives to costly pure sugars and food crops are introduced. The operational modes and fermentation methods that have been recently reported to improve lactic acid production in terms of concentrations, yields, and productivities are summarized and compared. High cell density fermentation through immobilization and cell-recycling techniques are also addressed. Finally, advances in recovery processes and concluding remarks on the future outlook of lactic acid production are presented.

  18. Bacteriocins From Lactic Acid Bacteria: Interest For Food Products Biopreservation

    OpenAIRE

    Dortu, C.; Thonart, Philippe

    2009-01-01

    Bacteriocins from lactic acid bacteria: interest for food products biopreservation. Bacteriocins from lactic acid bacteria are low molecular weight antimicrobial peptides. They have inhibitory activity against the bacteria that are closed related to the producer strains and a narrow inhibitory spectrum. Nevertheless, most of them have activity against some food-born pathogenic bacteria as Listeria monocytogenes. The application of bacteriocins or bacteriocin producing lactic acid bacteria in ...

  19. Modeling the continuous lactic acid production process from wheat flour.

    Science.gov (United States)

    Gonzalez, Karen; Tebbani, Sihem; Lopes, Filipa; Thorigné, Aurore; Givry, Sébastien; Dumur, Didier; Pareau, Dominique

    2016-01-01

    A kinetic model of the simultaneous saccharification, protein hydrolysis, and fermentation (SSPHF) process for lactic acid production from wheat flour has been developed. The model describes the bacterial growth, substrate consumption, lactic acid production, and maltose hydrolysis. The model was fitted and validated with data from SSPHF experiments obtained under different dilution rates. The results of the model are in good agreement with the experimental data. Steady state concentrations of biomass, lactic acid, glucose, and maltose as function of the dilution rate were predicted by the model. This steady state analysis is further useful to determine the operating conditions that maximize lactic acid productivity.

  20. SCREENING OF BACTERIA FOR LACTIC ACID PRODUCTION FROM WHEY WATER

    Directory of Open Access Journals (Sweden)

    Vethakanraj Helen Shiphrah

    2013-01-01

    Full Text Available Lactobacilli have the property of converting lactose and other sugars to lactic acid through fermentation. So whey water, the greenish translucent liquid rich in lactose, vitamins, proteins and mineral salts, obtained as a by-product after the precipitation of cheese can be used as a substrate for Lactobacilli for lactic acid production which otherwise is a serious environmental pollutant when disposed without pre-treatment. 16 isolates of Lactic acid producing bacteria isolated from various biological sources were inoculated in whey water (1% inoculum and kept at 37°C in the shaker at a speed of 150 revolutions per minute for 36 h. Lactic acid production was estimated after 36 h and the strains 4a, 12a and 15b showed lactic acid production of which 12a produced the highest concentration. The amount of Lactic acid produced by 12a was 0.62 g L-1 under unadjusted condition which is comparable to previously reported strains in enriched medium. So the lactic acid production by strain 12a was further investigated to find the effect of pH and temperature on the production efficiency. Lactic acid production was also checked in Luria-Bertani broth and whey water was found to be the medium of choice for prolonged lactic acid production.

  1. [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.

  2. Beneficial effects of antioxidative lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    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.

  3. Microbial production of lactic acid: the latest development.

    Science.gov (United States)

    Juturu, Veeresh; Wu, Jin Chuan

    2016-12-01

    Lactic acid is an important platform chemical for producing polylactic acid (PLA) and other value-added products. It is naturally produced by a wide spectrum of microbes including bacteria, yeast and filamentous fungi. In general, bacteria ferment C5 and C6 sugars to lactic acid by either homo- or hetero-fermentative mode. Xylose isomerase, phosphoketolase, transaldolase, l- and d-lactate dehydrogenases are the key enzymes that affect the ways of lactic acid production. Metabolic engineering of microbial strains are usually needed to produce lactic acid from unconventional carbon sources. Production of d-LA has attracted much attention due to the demand for producing thermostable PLA, but large scale production of d-LA has not yet been commercialized. Thermophilic Bacillus coagulans strains are able to produce l-lactic acid from lignocellulose sugars homo-fermentatively under non-sterilized conditions, but the lack of genetic tools for metabolically engineering them severely affects their development for industrial applications. Pre-treatment of agriculture biomass to obtain fermentable sugars is a pre-requisite for utilization of the huge amounts of agricultural biomass to produce lactic acid. The major challenge is to obtain quality sugars of high concentrations in a cost effective-way. To avoid or minimize the use of neutralizing agents during fermentation, genetically engineering the strains to make them resist acidic environment and produce lactic acid at low pH would be very helpful for reducing the production cost of lactic acid.

  4. Lactic acid Production with in situ Extraction in Membrane Bioreactor

    Directory of Open Access Journals (Sweden)

    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.

  5. 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

  6. 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

  7. Metabolic engineering as a tool for enhanced lactic acid production.

    Science.gov (United States)

    Upadhyaya, Bikram P; DeVeaux, Linda C; Christopher, Lew P

    2014-12-01

    Metabolic engineering is a powerful biotechnological tool that finds, among others, increased use in constructing microbial strains for higher lactic acid productivity, lower costs and reduced pollution. Engineering the metabolic pathways has concentrated on improving the lactic acid fermentation parameters, enhancing the acid tolerance of production organisms and their abilities to utilize a broad range of substrates, including fermentable biomass-derived sugars. Recent efforts have focused on metabolic engineering of lactic acid bacteria as they produce high yields and have a small genome size that facilitates their genetic manipulation. We summarize here the current trends in metabolic engineering techniques and strategies for manipulating lactic acid producing organisms developed to address and overcome major challenges in the lactic acid production process.

  8. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery.

  9. Towards lactic acid bacteria-based biorefineries.

    Science.gov (United States)

    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.

  10. 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 b

  11. Bacteriocins of lactic acid bacteria : extending the family

    NARCIS (Netherlands)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-01-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceo

  12. 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. RES

  13. 9th International Symposium on Lactic Acid Bacteria

    NARCIS (Netherlands)

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

    2008-01-01

    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

  14. 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 indust

  15. Bacteriocins of lactic acid bacteria : extending the family

    NARCIS (Netherlands)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-01-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are

  16. Functional genomics of lactic acid bacteria: from food to health

    NARCIS (Netherlands)

    Douillard, F.P.; Vos, de W.M.

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria a

  17. Engineering metabolic highways in Lactococci and other lactic acid bacteria

    NARCIS (Netherlands)

    Vos, de W.M.; Hugenholtz, J.

    2004-01-01

    Lactic acid bacteria (LAB) are widely used in industrial food fermentations and are receiving increased attention for use as cell factories for the production of food and pharmaceutical products. Glycolytic conversion of sugars into lactic acid is the main metabolic highway in these Gram-positive

  18. Functional genomics of lactic acid bacteria: from food to health

    NARCIS (Netherlands)

    Douillard, F.P.; Vos, de W.M.

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria

  19. Bacteriocins of lactic acid bacteria : extending the family

    NARCIS (Netherlands)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-01-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceo

  20. Capillary microreactors for lactic acid extraction: experimental and modelling study

    NARCIS (Netherlands)

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

    2015-01-01

    Lactic acid is an important biobased chemical and, among others, is used for the production of poly-lactic acid. Down-stream processing using state of the art technology is energy intensive and leads to the formation of large amounts of salts. In this presentation, experimental and modeling studies

  1. 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

  2. Engineering metabolic highways in Lactococci and other lactic acid bacteria

    NARCIS (Netherlands)

    Vos, de W.M.; Hugenholtz, J.

    2004-01-01

    Lactic acid bacteria (LAB) are widely used in industrial food fermentations and are receiving increased attention for use as cell factories for the production of food and pharmaceutical products. Glycolytic conversion of sugars into lactic acid is the main metabolic highway in these Gram-positive ba

  3. Exopolysaccharides from sourdough lactic acid bacteria.

    Science.gov (United States)

    Galle, Sandra; Arendt, Elke K

    2014-01-01

    The use of sourdough improves the quality and increases the shelf life of bread. The positive effects are associated with metabolites produced by lactic acid bacteria (LAB) during sourdough fermentation, including organic acids, exopolysaccharides (EPS), and enzymes. EPS formed during sourdough fermentation by glycansucrase activity from sucrose influence the viscoelastic properties of the dough and beneficially affect the texture and shelf life (in particular, starch retrogradation) of bread. Accordingly, EPS have the potential to replace hydrocolloids currently used as bread improvers and meet so the consumer demands for a reduced use of food additives. In this review, the current knowledge about the functional aspects of EPS formation by sourdough LAB especially in baking applications is summarized.

  4. 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 tha

  5. Effects of Lactic Acid Bacteria Inoculated Fermentation on Pickled Cucumbers

    OpenAIRE

    2013-01-01

    The aim of this study was to determine the effects of Lactic Acid Bacteria (LAB) fermentation on the texture and organic acid of pickled cucumbers. Texture and sensory evaluation as well as a microscopic observation were performed to study the textural differences among fresh cucumber, Spontaneous fermentation (SF) cucumber and LAB Inoculating Fermentation (LABIF) cucumber. Accumulation of seven organic acids i.e., oxalic, tartaric, malic, lactic, acetic, citric and succinic acid during cucum...

  6. 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.

  7. Biotechnological production of enantiomerically pure d-lactic acid.

    Science.gov (United States)

    Klotz, Silvia; Kaufmann, Norman; Kuenz, Anja; Prüße, Ulf

    2016-11-01

    The fermentation process of l-lactic acid is well known. Little importance was attached to d-lactic acid, but in the past 10 years, d-lactic acid gained significantly in importance. d-Lactic acid is an interesting precursor for manufacturing heat-resistant polylactic acid (PLA) bioplastics which can be widely used, for example as packaging material, coatings, for textiles or in the automotive industry.This review provides a comprehensive overview of the most recent developments, including a spectrum of studied microorganisms and their capabilities for the production of d-lactic acid. Additionally, the technological achievements in biotechnological d-lactic acid production including fermentation techniques like fed batch, simultaneous saccharification, and fermentation and continuous techniques are presented. Attention is also turned to suitable alternative substrates and their applicability in fermentation processes. Furthermore, advantages and disadvantages of product recovery and purification are discussed. Economic aspects of PLA are pointed out, and the present industrial producers of lactic acid are briefly introduced.

  8. Progress in engineering acid stress resistance of lactic acid bacteria.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2014-02-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of fermented foods, and are considered as probiotic due to their health-promoting effect. However, LAB encounter various environmental stresses both in industrial fermentation and application, among which acid stress is one of the most important survival challenges. Improving the acid stress resistance may contribute to the application and function of probiotic action to the host. Recently, the advent of genomics, functional genomics and high-throughput technologies have allowed for the understanding of acid tolerance mechanisms at a systems level, and many method to improve acid tolerance have been developed. This review describes the current progress in engineering acid stress resistance of LAB. Special emphasis is placed on engineering cellular microenvironment (engineering amino acid metabolism, introduction of exogenous biosynthetic capacity, and overproduction of stress response proteins) and maintaining cell membrane functionality. Moreover, strategies to improve acid tolerance and the related physiological mechanisms are also discussed.

  9. From lactic acid to poly(lactic acid) (PLA): characterization and analysis of PLA and its precursors.

    Science.gov (United States)

    Inkinen, Saara; Hakkarainen, Minna; Albertsson, Ann-Christine; Södergård, Anders

    2011-03-14

    The quality of the monomers lactic acid and lactide as well as the chemical changes induced during polymerization and processing are crucial parameters for controlling the properties of the resulting poly(lactic acid) (PLA) products. This review presents the most important analysis and characterization methods for quality assessment of PLA and its precursors. The impurities typically present in lactic acid or lactide monomers and their possible origins and effects on resulting PLA products are discussed. The significance of the analyses for the different polymer production stages is considered, and special applications of the methods for studying features specific for PLA-based materials are highlighted.

  10. Time related total lactic acid bacteria population diversity and ...

    African Journals Online (AJOL)

    ... diversity and dominance in cowpea-fortified fermented cereal-weaning food. ... in the spontaneous fermentation of malted cowpea fortified cereal weaning food ... those in Genbank database revealed that, the dominating lactic acid bacteria ...

  11. Production of lactic acid from Starchy-based food substrates

    African Journals Online (AJOL)

    SARAH

    2013-11-30

    Nov 30, 2013 ... Keywords: Starchy substrates, Fermentation, Lactic acid, Spectrophotometric ... substrates such as glucose and lactose are used but are rather costly. ..... 4days or when blended (solid state fermentation) and left to ferment for ...

  12. Technologically important properties of lactic acid bacteria isolated ...

    African Journals Online (AJOL)

    SERVER

    2007-07-18

    Jul 18, 2007 ... strains displaying the general characteristics of lactic acid bacteria were chosen ...... Food Flavour: Generation Analysis and Process Influence. Amsterdam, The ... Farah Z, Streiff T, Bachmann M R (1990). Preparation and ...

  13. Novel applications of Lactic Acid Bacteria (LAB) and Recombinant ...

    African Journals Online (AJOL)

    Novel applications of Lactic Acid Bacteria (LAB) and Recombinant LAB as ... through acidification, competition for essential nutrients, and / or production of inhibitory ... that allows the expression of heterologous proteins, they are being probed ...

  14. DNA fingerprinting of lactic acid bacteria in sauerkraut fermentations

    Science.gov (United States)

    Previous studies using traditional biochemical methods to study the ecology of commercial sauerkraut fermentations revealed that four lactic acid bacteria species, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis were the primary microorganisms in...

  15. Mixed cultures of Kimchi lactic acid bacteria show increased cell ...

    African Journals Online (AJOL)

    ufuoma

    kimchi lactobacilli on batch fermentation increased the cell density and lactic acid production with low nutrients .... first series of fermentations were carried out using pure cultures of each ... Each number represents the mean. ± SD of three ...

  16. Identification of lactic acid bacteria isolated from corn stovers

    National Research Council Canada - National Science Library

    PANG, Huili; ZHANG, Meng; QIN, Guangyong; TAN, Zhongfang; LI, Zongwei; WANG, Yanping; CAI, Yimin

    2011-01-01

    One hundred and twenty‐six strains were isolated from corn stover in Henan Province, China, of which 105 isolates were considered to be lactic acid bacteria (LAB) according to Gram‐positive, catalase...

  17. Lactic Acid Bacterial Vaginosis among Outpatients in Addis Ababa

    African Journals Online (AJOL)

    Bernt Lindtjorn

    In healthy vagina, lactobacilli produce hydrogen peroxide and lactic acid. These lower ... vaginal flora, consisting of hydrogen peroxide-producing lactobacilli, are ..... Reid G, Jass J, Sebulsky T John K. Potential Uses of. Probiotics in Clinical ...

  18. Mechanocatalytic Production of Lactic Acid from Glucose by Ball Milling

    Directory of Open Access Journals (Sweden)

    Luyang Li

    2017-06-01

    Full Text Available A solvent-free process was developed for the direct production of lactic acid from glucose in a mechanocatalytic process in the presence of Ba(OH2, and a moderate lactic acid yield of 35.6% was obtained. Glucose conversion and lactic acid formation were favorable at higher catalyst/glucose mass ratios. However, at relatively lower catalyst/glucose mass ratios, they were greatly inhibited, and the promotion of fructose formation was observed. The mechanocatalytic process was applicable for various carbohydrates such as C5 sugars, C6 sugars, and disaccharides with 20–36% lactic acid yields achieved. This work provides a new pathway for the production of value-added chemicals from biomass resources.

  19. Crystallization kinetics of poly(lactic acid)-talc composites

    OpenAIRE

    Battegazzore, Daniele; Bocchini, Sergio; Frache, Alberto

    2011-01-01

    The crystallization kinetics of Poly(lactic acid) / talc composites were determined over a range of 0 wt.% to 15 wt.% of talc. Talc was found to change the crystallization kinetics. The presence of talc increases the crystallization rate and this increase is related to talc concentration and to crystallization temperature. In order to understand the effect of talc and PLA crystallinity on mechanical properties, dynamic mechanical thermal analyses were performed on Poly(lactic acid) / talc com...

  20. Materials and methods for efficient lactic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shengde (Sycamore, IL); Ingram, Lonnie O' Neal (Gainesville, FL); Shanmugam, Keelnatham T. (Gainesville, FL); Yomano, Lorraine (Gainesville, FL); Grabar, Tammy B. (Gainesville, FL); Moore, Jonathan C. (Gainesville, FL)

    2009-12-08

    The present invention provides derivatives of ethanologenic Escherichia coli K011 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.

  1. 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.

  2. The importance of lactic acid in migraines and fibromyalgia.

    Science.gov (United States)

    de Sá Ribeiro, Guido Assis Cachuba; Scola, Rosana Hermínia; Piovesan, Elcio Juliato; Wollmann Junior, Darley Rugeri; Paiva, Eduardo Dos Santos; da Cunha, Claudio Leinig Pereira; Werneck, Lineu Cesar

    2015-01-01

    Lactic acid is a byproduct of both muscle metabolism and the central nervous system. Changes in metabolism are related to various physiological and pathological conditions. The aim of this study was to determine the relationship between migraine and fibromyalgia with the levels of lactic acid in the blood. We study of 93 patients was divided into five groups: 1) patients with fibromyalgia (n=20); 2) episodic migraine (n=20); 3) chronic migraine (n=20); 4) fibromyalgia and episodic migraine (n= 13); and 5) fibromyalgia and chronic migraine (n=20), and 20 healthy subjects (control group). Blood levels of lactic acid were measured at four different time points: at rest, during aerobic exercise, during anaerobic physical activity and while resting after anaerobic exercise. Lactic acid increased in all groups during anaerobic physical activity without predominance for either group. During aerobic physical activity, all groups increased lactic acid levels, but the increase was more expressive in the chronic migraine group and the chronic migraine with fibromyalgia group without statistical significance. We did not found abnormalities involving the metabolism of lactic acid in episodic and chronic migraine with or without fibromyalgia. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

  3. Zinc Binding by Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Jasna Mrvčić

    2009-01-01

    Full Text Available Zinc is an essential trace element in all organisms. A common method for the prevention of zinc deficiency is pharmacological supplementation, especially in a highly available form of a metalloprotein complex. The potential of different microbes to bind essential and toxic heavy metals has recently been recognized. In this work, biosorption of zinc by lactic acid bacteria (LAB has been investigated. Specific LAB were assessed for their ability to bind zinc from a water solution. Significant amount of zinc ions was bound, and this binding was found to be LAB species-specific. Differences among the species in binding performance at a concentration range between 10–90 mg/L were evaluated with Langmuir model for biosorption. Binding of zinc was a fast process, strongly influenced by ionic strength, pH, biomass concentration, and temperature. The most effective metal-binding LAB species was Leuconostoc mesenteroides (27.10 mg of Zn2+ per gram of dry mass bound at pH=5 and 32 °C, during 24 h. FT-IR spectroscopy analysis and electron microscopy demonstrated that passive adsorption and active uptake of the zinc ions were involved.

  4. Microbial granulation for lactic acid production

    DEFF Research Database (Denmark)

    Kim, Dong-Hoon; Lee, Mo-Kwon; Hwang, Yuhoon

    2016-01-01

    was fed with 2% glucose and operated at a hydraulic retention time (HRT) of 12 h and pH 5.0 ± 0.1 under a thermophilic condition (50°C). The mixed liquor in the CSTR was then transferred to an up-flow anaerobic sludge blanket reactor (UASB). The fermentation performance and granulation process were......This work investigated the formation of microbial granules to boost the productivity of lactic acid (LA). The flocculated form of LA-producing microbial consortium, dominated by Lactobacillus sp. (91.5% of total sequence), was initially obtained in a continuous stirred-tank reactor (CSTR), which...... monitored with a gradual decrease of HRT from 8.0 to 0.17 h, corresponding to an increase in the substrate loading from 60 to 2,880 g glucose L−1d−1. As the operation continued, the accumulation of biomass in the UASB was clearly observed, which changed from flocculent to granular form with decrease in HRT...

  5. Bacterial adherence to titanium, poly-L-lactic acid, and composite hydroxyapatite and poly-L-lactic acid interference screws.

    Science.gov (United States)

    Masini, Brendan D; Stinner, Daniel J; Waterman, Scott M; Wenke, Joseph C; Gerlinger, Tad L

    2012-01-01

    This study investigates a potential site of bacterial adherence, the implant surface, comparing titanium, poly-L-lactic acid (PLLA), and composite hydroxyapatite and poly-L-lactic acid (PLLA-HA) interference screws using a bioluminescent in vitro model. Interference screws of three materials, titanium (Arthrex, Naples, FL), bioabsorbable poly-L-lactic acid (BIORCI, Smith & Nephew, Andover, MA), and bioabsorbable composite hydroxyapatite and poly-L-lactic acid (BIORCI-HA, Smith & Nephew, Andover, MA) were immersed in a broth of bioluminescent Staphylococcus aureus. The screws were irrigated and then imaged with a photon-capturing camera system yielding a total photon count correlating with residual adherent bacteria. The titanium screws had the lowest mean total bacterial counts followed by the PLLA-HA screws and with the PLLA screws having the highest mean total counts. The difference in means between the titanium group and the PLLA group was statistically significant (p bacterial adherence than comparable bioabsorbable PLLA screws.

  6. Poly(lactic acid) and poly(lactic-co-glycolic acid) particles as versatile carrier platforms for vaccine delivery.

    Science.gov (United States)

    Pavot, Vincent; Berthet, Morgane; Rességuier, Julien; Legaz, Sophie; Handké, Nadège; Gilbert, Sarah C; Paul, Stéphane; Verrier, Bernard

    2014-12-01

    The development of safe and effective vaccines for cancer and infectious diseases remains a major goal in public health. Over the last two decades, controlled release of vaccine antigens and immunostimulant molecules has been achieved using nanometer or micron-sized delivery vehicles synthesized using biodegradable polymers. In addition to achieving a depot effect, enhanced vaccine efficacy using such delivery vehicles has been attributed to efficient targeting of antigen presenting cells such as dendritic cells. Biodegradable and biocompatible poly(lactic acid) and poly(lactic-co-glycolic acid) polymers belong to one such family of polymers that have been a popular choice of material used in the design of these delivery vehicles. This review summarizes research findings from ourselves and others highlighting the promise of poly(lactic acid)- and poly(lactic-co-glycolic acid)-based vaccine carriers in enhancing immune responses.

  7. Metabolite Profiles of Lactic Acid Bacteria in Grass Silage▿

    OpenAIRE

    Broberg, Anders; Jacobsson, Karin; Ström, Katrin; Schnürer, Johan

    2007-01-01

    The metabolite production of lactic acid bacteria (LAB) on silage was investigated. The aim was to compare the production of antifungal metabolites in silage with the production in liquid cultures previously studied in our laboratory. The following metabolites were found to be present at elevated concentrations in silos inoculated with LAB strains: 3-hydroxydecanoic acid, 2-hydroxy-4-methylpentanoic acid, benzoic acid, catechol, hydrocinnamic acid, salicylic acid, 3-phenyllactic acid, 4-hydro...

  8. Safety evaluation of poly(lactic-co-glycolic acid)/poly(lactic-acid) microspheres through intravitreal injection in rabbits

    OpenAIRE

    Rong XF; Yuan WE; Lu Y; Mo XF

    2014-01-01

    Xianfang Rong,1 Weien Yuan,2 Yi Lu,1 Xiaofen Mo11Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, People’s Republic of China; 2School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaAbstract: Poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic-acid) (PLA) microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of P...

  9. Efficacy of fungicide combinations, phosphoric acid, and plant extract from stinging nettle on potato late blight management and tuber yield

    Science.gov (United States)

    Late blight, caused by Phytophthora infestans is a major constraint to potato production. Inadequate management of the disease has often resulted in heavy losses in various production regions. We assessed the efficacy of fungicides, phosphoric acid, and stinging nettle plant extract combinations for...

  10. Genetics of the proteolytic system of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan

    1990-01-01

    The proteolytic system of lactic acid bacteria is of eminent importance for the rapid growth of these organisms in protein-rich media. The combined action of proteinases and peptidases provides the cell with small peptides and essential amino acids. The amino acids and peptides thus liberated have t

  11. Genetics of the proteolytic system of lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan

    1990-01-01

    The proteolytic system of lactic acid bacteria is of eminent importance for the rapid growth of these organisms in protein-rich media. The combined action of proteinases and peptidases provides the cell with small peptides and essential amino acids. The amino acids and peptides thus liberated have

  12. Stress Physiology of Lactic Acid Bacteria.

    Science.gov (United States)

    Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A; Linares, Daniel M; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie; Kok, Jan

    2016-09-01

    Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

  13. Microbial granulation for lactic acid production.

    Science.gov (United States)

    Kim, Dong-Hoon; Lee, Mo-Kwon; Hwang, Yuhoon; Im, Wan-Taek; Yun, Yeo-Myeong; Park, Chul; Kim, Mi-Sun

    2016-01-01

    This work investigated the formation of microbial granules to boost the productivity of lactic acid (LA). The flocculated form of LA-producing microbial consortium, dominated by Lactobacillus sp. (91.5% of total sequence), was initially obtained in a continuous stirred-tank reactor (CSTR), which was fed with 2% glucose and operated at a hydraulic retention time (HRT) of 12 h and pH 5.0 ± 0.1 under a thermophilic condition (50°C). The mixed liquor in the CSTR was then transferred to an up-flow anaerobic sludge blanket reactor (UASB). The fermentation performance and granulation process were monitored with a gradual decrease of HRT from 8.0 to 0.17 h, corresponding to an increase in the substrate loading from 60 to 2,880 g glucose L(-1) d(-1) . As the operation continued, the accumulation of biomass in the UASB was clearly observed, which changed from flocculent to granular form with decrease in HRT. Up to the HRT decrease to 0.5 h, the LA concentration was maintained at 19-20 g L(-1) with over 90% of substrate removal efficiency. However, further decrease of HRT resulted in a decrease of LA concentration with increase in residual glucose. Nevertheless, the volumetric LA productivity continuously increased, reaching 67 g L-fermenter (-1) h(-1) at HRT 0.17 h. The size of LA-producing granules and hydrophobicity gradually increased with decrease in HRT, reaching 6.0 mm and 60%, respectively. These biogranules were also found to have high settling velocities and low porosities, ranging 2.69-4.73 cm s(-1) and 0.39-0.92, respectively. © 2015 Wiley Periodicals, Inc.

  14. Overexpression of ESBP6 improves lactic acid resistance and production in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sugiyama, Minetaka; Akase, Shin-Pei; Nakanishi, Ryota; Kaneko, Yoshinobu; Harashima, Satoshi

    2016-10-01

    Polylactic acid plastics are receiving increasing attention for the control of atmospheric CO2 emissions. Lactic acid, the building block for polylactic acid, is produced by fermentation technology from renewable carbon sources. The yeast Saccharomyces cerevisiae, harboring the lactate dehydrogenases gene (LDH), produces lactic acid at a large scale due to its strong acid resistance, to its simple nutritional requirements and to its ease of genetic engineering. Since improvement of lactic acid resistance is correlated with an increase of lactic acid production under non-neutralizing condition, we isolated a novel gene that enhances lactic acid resistance using a multi-copy yeast genomic DNA library. In this study, we identified the ESBP6 gene, which increases lactic acid resistance when overexpressed and which encodes a protein with similarity to monocarboxylate permeases. Although ESBP6 was not induced in response to lactic acid stress, it caused weak but reproducible sensitivity to lactic acid when disrupted. Furthermore, intracellular pH in the ESBP6 overexpressing strain was higher than that in the wild-type strain under lactic acid stressed condition, suggesting that Esbp6 plays some roles in lactic acid adaptation response. The ESBP6 overexpressing strain carrying the LDH gene induced 20% increase in lactic acid production compared with the wild-type strain carrying the LDH gene under non-neutralizing conditions. These results indicate that overexpression of ESBP6 provides a novel and useful tool to improve lactic acid resistance and lactic acid production in yeast.

  15. Functional genomics of lactic acid bacteria: from food to health.

    Science.gov (United States)

    Douillard, François P; de Vos, Willem M

    2014-08-29

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health.

  16. Metabolite Profiles of Lactic Acid Bacteria in Grass Silage▿

    Science.gov (United States)

    Broberg, Anders; Jacobsson, Karin; Ström, Katrin; Schnürer, Johan

    2007-01-01

    The metabolite production of lactic acid bacteria (LAB) on silage was investigated. The aim was to compare the production of antifungal metabolites in silage with the production in liquid cultures previously studied in our laboratory. The following metabolites were found to be present at elevated concentrations in silos inoculated with LAB strains: 3-hydroxydecanoic acid, 2-hydroxy-4-methylpentanoic acid, benzoic acid, catechol, hydrocinnamic acid, salicylic acid, 3-phenyllactic acid, 4-hydroxybenzoic acid, (trans, trans)-3,4-dihydroxycyclohexane-1-carboxylic acid, p-hydrocoumaric acid, vanillic acid, azelaic acid, hydroferulic acid, p-coumaric acid, hydrocaffeic acid, ferulic acid, and caffeic acid. Among these metabolites, the antifungal compounds 3-phenyllactic acid and 3-hydroxydecanoic acid were previously isolated in our laboratory from liquid cultures of the same LAB strains by bioassay-guided fractionation. It was concluded that other metabolites, e.g., p-hydrocoumaric acid, hydroferulic acid, and p-coumaric acid, were released from the grass by the added LAB strains. The antifungal activities of the identified metabolites in 100 mM lactic acid were investigated. The MICs against Pichia anomala, Penicillium roqueforti, and Aspergillus fumigatus were determined, and 3-hydroxydecanoic acid showed the lowest MIC (0.1 mg ml−1 for two of the three test organisms). PMID:17616609

  17. Compatible solutes in lactic acid bacteria subjected to water stress.

    NARCIS (Netherlands)

    Kets, E.P.W.

    1997-01-01

    The goal of the research project described in this thesis was to investigate the protective effect of compatible solutes on tactic acid bacteria subjected to drying. Dried preparations of lactic acid bacteria are applied as starter cultures in feed and food industries. Dried starter cultures compare

  18. Enzymatic activity toward poly(L-lactic acid) implants

    NARCIS (Netherlands)

    Schakenraad, J.M.; Hardonk, M.J.; Feijen, J.; Molenaar, I.; Nieuwenhuis, P.

    1990-01-01

    Tissue reactions toward biodegradable poly(L-lactic acid) implants were monitored by studying the activity pattern of seven enzymes as a function of time: alkaline phosphatase, acid phosphatase, -naphthyl acetyl esterase, -glucuronidase, ATP-ase, NADH-reductase, and lactate dehydrogenase. Cell types

  19. Novel extractants for the recovery of fermentation derived lactic acid

    NARCIS (Netherlands)

    Krzyzaniak, A.; Leeman, M.; Vossebeld, F.; Visser, T.J.; Schuur, Boelo; de Haan, A.B.

    2013-01-01

    Reactive liquid–liquid extraction is a promising technology for the removal of lactic acid directly from fermentation media. For over five decades, tertiary amines (e.g. trioctyl amine) have been the state-of-the-art extractants for carboxylic acid extraction. However, to make fermentative carboxyli

  20. Genetic Engineering of Rhizopus for Enhancing Lactic Acid Production

    Science.gov (United States)

    The fungus Rhizopus is frequently used to convert, or ferment sugars obtained from agricultural crops to lactic acid. This natural product has long been utilized by the food industry as an additive for preservation, flavor, and acidity. Additionally, it is used for the manufacture of environmental...

  1. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    Institute of Scientific and Technical Information of China (English)

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  2. 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....

  3. Lactic Acid Bacteria Differentially Activate Natural Killer Cells

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen; Christensen, Hanne Risager; Frøkiær, Hanne

    Background: Natural killer (NK) cells are lymphocytes of the non-specific immune system recognizing cancerous cells and cells altered by viral infection. Recently, it was proposed that a non-cytolytic subset of NK cells serves a regulatory role by secreting cytokines, possibly affecting both...... 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...... at describing strain-dependent effects of lactic acid bacteria on regulatory functions of NK-cells. Here, we have investigated how human gut flora-derived non-pathogenic lactic acid bacteria affect NK cells in vitro, by measuring proliferation and IFN-gamma production of human peripheral blood NK cells upon...

  4. 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.

  5. Isolation of lactic acid-forming bacteria from biogas plants.

    Science.gov (United States)

    Bohn, Jelena; Yüksel-Dadak, Aytül; Dröge, Stefan; König, Helmut

    2017-02-20

    Direct molecular approaches provide hints that lactic acid bacteria play an important role in the degradation process of organic material to methanogenetic substrates in biogas plants. However, their diversity in biogas fermenter samples has not been analyzed in detail yet. For that reason, five different biogas fermenters, which were fed mainly with maize silage and manure from cattle or pigs, were examined for the occurrence of lactic acid-forming bacteria. A total of 197 lactic acid-forming bacterial strains were isolated, which we assigned to 21 species, belonging to the genera Bacillus, Clostridium, Lactobacillus, Pediococcus, Streptococcus and Pseudoramibacter-related. A qualitative multiplex system and a real-time quantitative PCR could be developed for most isolates, realized by the selection of specific primers. Their role in biogas plants was discussed on the basis of the quantitative results and on physiological data of the isolates.

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

    Science.gov (United States)

    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.

  7. Molecular screening of wine lactic acid bacteria degrading hydroxycinnamic acids.

    Science.gov (United States)

    de las Rivas, Blanca; Rodríguez, Héctor; Curiel, José Antonio; Landete, José María; Muñoz, Rosario

    2009-01-28

    The potential to produce volatile phenols from hydroxycinnamic acids was investigated for lactic acid bacteria (LAB) isolated from Spanish grape must and wine. A PCR assay was developed for the detection of LAB that potentially produce volatile phenols. Synthetic degenerate oligonucleotides for the specific detection of the pdc gene encoding a phenolic acid decarboxylase were designed. The pdc PCR assay amplifies a 321 bp DNA fragment from phenolic acid decarboxylase. The pdc PCR method was applied to 85 strains belonging to the 6 main wine LAB species. Lactobacillus plantarum, Lactobacillus brevis, and Pediococcus pentosaceus strains produce a positive response in the pdc PCR assay, whereas Oenococcus oeni, Lactobacillus hilgardii, and Leuconostoc mesenteroides strains did not produce the expected PCR product. The production of vinyl and ethyl derivatives from hydroxycinnamic acids in culture media was determined by high-performance liquid chromatography. A relationship was found between pdc PCR amplification and volatile phenol production, so that the LAB strains that gave a positive pdc PCR response produce volatile phenols, whereas strains that did not produce a PCR amplicon did not produce volatile phenols. The proposed method could be useful for a preliminary identification of LAB strains able to produce volatile phenols in wine.

  8. 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...

  9. 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.

  10. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    Science.gov (United States)

    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.

  11. Lactic acid bacteria found in fermented fish in Thailand.

    Science.gov (United States)

    Tanasupawat, Somboon; Okada, Sanae; Komagata, Kazuo

    1998-06-01

    Forty-seven strains of homofermentative rod-shaped and 5 heterofermentative sphere-shaped lactic acid bacteria were isolated from 4 kinds of fermented fish (pla-ra, pla-chom, kung-chom, and hoi-dong) in Thailand. These bacteria were separated into four groups by phenotypic and chemotaxonomic characteristics, including fluorometric DNA-DNA hybridization. Five strains (Group I) contained meso-diaminopimelic acid in the cell wall. Four strains were identified as Lactobacillus pentosus, and one strain was L. plantarum. Tested strains of this group produced DL-lactic acid. The rest of the rod-shaped bacteria, 23 strains (Group II) and 19 strains (Group III), lacked meso-diaminopimelic acid in the cell wall and were identified as L. farciminis and Lactobacillus species, respectively. The tested strains of these groups produced L-lactic acid. The amount of cellular fatty acids of C16:0 and C18:1, and the DNA base compositions were significant for differentiating the strains in Groups II and III. Five strains of cocci in chains (Group IV) produced gas from glucose. The tested strains of this group produced d-lactic acid. They were identified as a Leuconostoc species. The distribution of these bacteria in fermented fish in Thailand is discussed.

  12. LACTIC ACID BACTERIA AND THEIR ROLE IN THE MEAT PROCESSING

    Directory of Open Access Journals (Sweden)

    Josef Kameník

    2016-01-01

    Full Text Available Abstract Lactic acid bacteria (LAB play in meat processing a positive but also a negative role. The principal advantage of LAB in the production of dry fermented sausages lies in the fermentation of saccharides, i.e. the creation of lactic acid and the subsequent fall in pH. The role of LAB in fresh meat spoilage is still controversial. Several species are able to dominate the meat system in VP and MAP storage conditions and can release odor-impact molecules. On the other hand they can provide favorable antagonistic activity against other undesired microorganisms. LAB are important spoilage agents in cooked meat products.

  13. Antifungal Poly(lactic acid Films Containing Thymol and Carvone

    Directory of Open Access Journals (Sweden)

    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.

  14. Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures.

    Science.gov (United States)

    Magala, Michal; Kohajdová, Zlatica; Karovičová, Jolana

    2013-01-01

    Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefits like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability). Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Variations in tarhana recipe (salt absence, increased proportion of yoghurt) led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid). Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that standard tarhana fermented for 144 h had the highest overall acceptability.

  15. Preparation of lactic acid bacteria fermented wheat-yoghurt mixtures

    Directory of Open Access Journals (Sweden)

    Michal Magala

    2013-09-01

    Full Text Available Background. Tarhana, a wheat-yoghurt fermented mixture, is considered as a good source of saccharides, proteins, some vitamins and minerals. Moreover, their preparation is inexpensive and lactic acid fermentation offers benefi ts like product preservation, enhancement of nutritive value and sensory properties improvement. The aim of this work was to evaluate changes of some chemical parameters during fermentation of tarhana, when the level of salt and amount of yoghurt used were varied. Some functional and sensory characteristics of the fi nal product were also determined. Material and methods. Chemical analysis included determination of pH, titrable acidity, content of reducing saccharides, lactic, acetic and citric acid. Measured functional properties of tarhana powder were foaming capacity, foam stability, water absorption capacity, oil absorption capacity and emulsifying activity. Tarhana soups samples were evaluated for their sensory characteristics (colour, odor, taste, consistency and overall acceptability. Results. Fermentation of tarhana by lactic acid bacteria and yeasts led to decrease in pH, content of reducing saccharides and citric acid, while titrable acidity and concentration of lactic and acetic acid increased. Determination of functional properties of tarhana powder showed, that salt absence and increased amount of yoghurt in tarhana recipe reduced foaming capacity and oil absorption capacity, whereas foam stability and water absorption capacity were improved. Sensory evaluation of tarhana soups showed that variations in tarhana recipe adversly affected sensory parameters of fi nal products. Conclusion. Variations in tarhana recipe (salt absence, increased proportion of yoghurt led to changes in some chemical parameters (pH, titrable acidity, reducing saccharides, content of lactic, acetic and citric acid. Functional properties were also affected with changed tarhana recipe. Sensory characteristics determination showed, that

  16. Lactic acid from apple pomace: a laboratory experiment for teaching valorisation of wastes

    National Research Council Canada - National Science Library

    Alonso, J. L; Garrote, G; Domínguez, H; Santos, V; Parajó, J. C

    2009-01-01

    ...: starting from AP, hydrolytic enzymes and lactic acid bacteria present in yogurt, saccharification of the polysaccharides contained in AP and their fermentation into lactic acid are simultaneously carried out...

  17. 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...

  18. Potential of lactic acid bacteria as suppressors of wine allergies

    Directory of Open Access Journals (Sweden)

    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.

  19. Unstructured Models for Lactic Acid Fermentation – A Review

    Directory of Open Access Journals (Sweden)

    Abdallah Bouguettoucha

    2011-01-01

    Full Text Available To describe a microbial process, two kinds of models can be developed, structured and unstructured models. Contrary to structured models, which take into account some basic aspects of cell structure, their function and composition, no physiological characterization of cells is considered in unstructured models, which only consider total cellular concentration. However, in spite of their simplicity, unstructured models have proven to accurately describe lactic acid fermentation in a wide range of experimental conditions and media. A partial link between cell growth and production, namely the Luedeking and Piret model, is mostly considered by the authors. Culture pH is the main parameter to be considered for model development. Acidic pH leads to inhibitory concentrations of undissociated lactic acid, the main inhibitory component, which causes cessation of growth and then production. On the other hand, pH control at optimal value for LAB growth allows to overcome product inhibition (by the total lactic acid produced or its undissociated part; hence nutritional limitations have to be considered for model development. Nitrogen is mainly involved in cessation of growth, owing to the fastidious nutritional requirements of LAB, while lactic acid production ceased when carbon was exhausted from the medium. The lack of substrate inhibition when usual concentrations of carbon substrate are used should be noted.

  20. Vanadocene reactions with hydroxy acids. [Hydroxy acids: acetylsalicylic, gallic, lactic, salicyclic, orotic,. gamma. -hydroxybutyric acids

    Energy Technology Data Exchange (ETDEWEB)

    Latyaeva, V.N.; Lineva, A.N.; Zimina, S.V.; Ehllert, O.G.; Arsen' eva, T.I. (Gor' kovskij Meditsinskij Inst. (USSR))

    1984-03-01

    To prepare a series of vanadium cyclopentadienylcarboxylates soluble in water, the vanadocene reactions with lactic, ..gamma..-oxybutyric-, salicylic,- gallic-, orotic-, and acetylsalicylic acids have been studied. To determine the influence of cyclopentadienyl groups, bound with a vanadium atom, on the physiological activity of the complexes formed, vanadium halides are made to react with lactic acid. Only the vanadocene reaction with orotic acid was conducted in an aqueous medium, other interactions were realized in the diethyl ether, toluene, T, H, P medium. The interaction of vanadocene and vanadium halides with lactic-, salicylic-, acetylsalicylic- and gallic acids was found to lead to the formation of water-soluble vanadium complexes of Cp/sub 2/, VOCOR or CpV (OCOR)/sub 2/ type. The data on the produced compounds yield, their IR spectra, decomposition temperatures, solubility, effective magnetic moments are presented.

  1. 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....

  2. DRY COMPOSITION OF STARTER CULTURES FORM LACTIC ACID MICROORGANISMS

    Directory of Open Access Journals (Sweden)

    At. Kraevska

    2014-03-01

    Full Text Available The purpose of this work is to investigate the possibility of producing of lyophilized lactic acid starter Lb. plantarum strain 226/1, designed for a starter culture in the production of pickles. The results of our studies demonstrate achievement of this goal by the specified process parameters.

  3. Quorum sensing-controlled gene expression in lactic acid bacteria

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Ruyter, Pascalle G.G.A. de; Kleerebezem, Michiel; Vos, Willem M. de

    1998-01-01

    Quorum sensing in lactic acid bacteria (LAB) involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular response regulator. This regulator in turn activates transcription of target genes, that commonly include the struc

  4. Antibacterial activity and probiotic properties of some Lactic Acid ...

    African Journals Online (AJOL)

    Client

    2013-05-15

    May 15, 2013 ... pre-selected for testing as potential probiotics by their ability to grow adequately at low pH values. In ... Thirteen (13) lactic acid bacteria (LAB) isolated from dairy ... existing ones, the screening of adhesion properties is.

  5. Poly(lactic acid) degradable plastics, coatings, and binders

    Energy Technology Data Exchange (ETDEWEB)

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-01-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids' being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  6. Poly(lactic acid) degradable plastics, coatings, and binders

    Energy Technology Data Exchange (ETDEWEB)

    Bonsignore, P.V.; Coleman, R.D.; Mudde, J.P.

    1992-05-01

    Biochemical processes to derive value from the management of high carbohydrate food wastes, such as potato starch, corn starch, and cheese whey permeate, have typically been limited to the production of either ethanol or methane. Argonne National Laboratory (ANL) believes that lactic acid presents an attractive option for an alternate fermentation end product, especially in light of lactic acids` being a viable candidate for conversion to environmentally safe poly(lactic acid) (PLA) degradable plastics, coatings, and binders. Technology is being developed at ANL to permit a more cost effective route to modified high molecular weight PLA. Preliminary data on the degradation behavior of these modified PLAs shows the retention to the inherent hydrolytic degradability of the PLA modified, however, by introduced compositional variables. A limited study was done on the hydrolytic stability of soluble oligomers of poly(L-lactic acid). Over a 34 day hold period, water-methanol solutions of Pl-LA oligomers in the 2-10 DP range retained some 75% of their original molecular weight.

  7. Short Communication Antibacterial Activities of Lactic Acid Bacteria ...

    African Journals Online (AJOL)

    2011-12-20

    Dec 20, 2011 ... vegetables, studies on LAB associated with lettuce, cucumber and cabbage are limited and non-existing in. Nigeria. ... Keywords: Antagonistic effect, Bacterial cell supernatant, Lactic acid bacteria, Vegetables ... gastrointestinal tracts of animals and humans. .... that different strains of LAB possess inhibitory.

  8. Effects of lactic acid bacteria contamination on lignocellulosic ethanol fermentation

    Science.gov (United States)

    Slower fermentation rates, mixed sugar compositions, and lower sugar concentrations may make lignocellulosic fermentations more susceptible to contamination by lactic acid bacteria (LAB), which is a common and costly problem to the corn-based fuel ethanol industry. To examine the effects of LAB con...

  9. Systems solutions by lactic acid bacteria: from paradigms to practice

    NARCIS (Netherlands)

    Vos, de W.M.

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serv

  10. Modelling strategies for the industrial exploitation of lactic acid bacteria

    NARCIS (Netherlands)

    Teusink, B.; Smid, E.J.

    2006-01-01

    Lactic acid bacteria (LAB) have a long tradition of use in the food industry, and the number and diversity of their applications has increased considerably over the years. Traditionally, process optimization for these applications involved both strain selection and trial and error. More recently, me

  11. Systems solutions by lactic acid bacteria: from paradigms to practice.

    Science.gov (United States)

    de Vos, Willem M

    2011-08-30

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications.

  12. Lactic acid and Lactates in Health and wellness

    NARCIS (Netherlands)

    Schaafsma, Gertjan; Schreurs, Victor

    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 perspec

  13. Temperature dependence of poly(lactic acid) mechanical properties

    DEFF Research Database (Denmark)

    Zhou, Chengbo; Guo, Huilong; Li, Jingqing

    2016-01-01

    The mechanical properties of polymers are not only determined by their structures, but also related to the temperature field in which they are located. The yield behaviors, Young's modulus and structures of injection-molded poly(lactic acid) (PLA) samples after annealing at different temperatures...

  14. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    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...

  15. A computerised system for the identification of lactic acid bacteria.

    NARCIS (Netherlands)

    Wijtzes, T.; Bruggeman, M.R.; Nout, M.J.R.; Zwietering, M.H.

    1997-01-01

    A generic computerised system for the identification of bacteria was developed. The system is equipped with a key to the identification of lactic acid bacteria. The identification is carried out in two steps. The first step distinguishes groups of bacteria by following a decision tree with general i

  16. Mucosal Vaccination and Therapy with Genetically Modified Lactic Acid Bacteria

    NARCIS (Netherlands)

    Wells, J.

    2011-01-01

    Lactic acid bacteria (LAB) have proved to be effective mucosal delivery vehicles that overcome the problem of delivering functional proteins to the mucosal tissues. By the intranasal route, both live and killed LAB vaccine strains have been shown to elicit mucosal and systemic immune responses that

  17. Lactic acid bacteria : the bugs of the new millennium

    NARCIS (Netherlands)

    Konings, W.N; Kok, J.; Kuipers, O.P.; Poolman, B.

    2000-01-01

    Lactic acid bacteria (LABs) are widely used in the manufacturing of fermented food and are among the best-studied microorganisms. Detailed knowledge of a number of physiological traits has opened new potential applications for these organisms in the food industry, while other traits might be benefic

  18. Screening of malting sorghum samples for lactic acid bacteria with ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-17

    Jun 17, 2009 ... variety of foods such as milk, meat, vegetables and malted cereals. ... him to extend the shelf life of many foods (Savadogo et al., 2004). .... After solidifying, wells were cut into it using a sterile cork borer 4 mm in diameter. ..... Antimicrobial producing lactic acid bacteria from raw barley and Sorghum. J.

  19. 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

  20. Quorum sensing-controlled gene expression in lactic acid bacteria

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Ruyter, Pascalle G.G.A. de; Kleerebezem, Michiel; Vos, Willem M. de

    1998-01-01

    Quorum sensing in lactic acid bacteria (LAB) involves peptides that are directly sensed by membrane-located histidine kinases, after which the signal is transmitted to an intracellular response regulator. This regulator in turn activates transcription of target genes, that commonly include the

  1. Biocompatibility of poly(DL-lactic acid/glycine) copolymers

    NARCIS (Netherlands)

    Schakenraad, J.M.; Dijkstra, Pieter J.

    1991-01-01

    In this review the authors discuss the polymer chemical, physical and cell biological aspects of poly (DL-lactic acid/glycine) copolymers, both in vitro and in vivo. The mechanism and rate of degradation and the degree of foreign body reaction were evaluated as a function of the molecular

  2. 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...

  3. 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, pr

  4. GAS PERMEATION PROPERTIES OF POLY(LACTIC ACID). (R826733)

    Science.gov (United States)

    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...

  5. Genetic manipulation of the peptidolytic system in lactic acid bacteria

    NARCIS (Netherlands)

    Kok, J; Venema, G

    1995-01-01

    Due to their presumed involvenment in product flavour the peptidases of lactic acid bacteria have been subject to extensive research. A major breakthrough, was the isolation and purification of the various enzymes to homogeniety. This allowed a reevaluation of the number of different enzymes in one

  6. Systems solutions by lactic acid bacteria: from paradigms to practice

    NARCIS (Netherlands)

    Vos, de W.M.

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which

  7. Make use of lactic acid bacteria in biomass to biofuel

    Science.gov (United States)

    Lactic acid bacteria (LAB) have been widely used in dairy fermentations, nutraceuticals, and probiotic/prebiotic applications. Selected strains from the LAB could potentially be used as microbial catalysts for production of fuels and chemicals from lignocellulosic biomass. The unique traits of lac...

  8. 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...

  9. Mucosal Vaccination and Therapy with Genetically Modified Lactic Acid Bacteria

    NARCIS (Netherlands)

    Wells, J.

    2011-01-01

    Lactic acid bacteria (LAB) have proved to be effective mucosal delivery vehicles that overcome the problem of delivering functional proteins to the mucosal tissues. By the intranasal route, both live and killed LAB vaccine strains have been shown to elicit mucosal and systemic immune responses that

  10. Heme and menaquinone induced electron transport in lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    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.

  11. Biocompatibility of poly (DL-lactic acid/glycine) copolymers

    NARCIS (Netherlands)

    Schakenraad, J.M.; Dijkstra, P.J.

    1991-01-01

    In this review the authors discuss the polymer chemical, physical and cell biological aspects of poly (DL-lactic acid/glycine) copolymers, both in vitro and in vivo. The mechanism and rate of degradation and the degree of foreign body reaction were evaluated as a function of the molecular compositi

  12. 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.

  13. Effect of phenolic acids on glucose and organic acid metabolism by lactic acid bacteria from wine.

    Science.gov (United States)

    Campos, Francisco M; Figueiredo, Ana R; Hogg, Tim A; Couto, José A

    2009-06-01

    The influence of phenolic (p-coumaric, caffeic, ferulic, gallic and protocatechuic) acids on glucose and organic acid metabolism by two strains of wine lactic acid bacteria (Oenococcus oeni VF and Lactobacillus hilgardii 5) was investigated. Cultures were grown in modified MRS medium supplemented with different phenolic acids. Cellular growth was monitored and metabolite concentrations were determined by HPLC-RI. Despite the strong inhibitory effect of most tested phenolic acids on the growth of O. oeni VF, the malolactic activity of this strain was not considerably affected by these compounds. While less affected in its growth, the capacity of L. hilgardii 5 to degrade malic acid was clearly diminished. Except for gallic acid, the addition of phenolic acids delayed the metabolism of glucose and citric acid in both strains tested. It was also found that the presence of hydroxycinnamic acids (p-coumaric, caffeic and ferulic) increased the yield of lactic and acetic acid production from glucose by O. oeni VF and not by L. hilgardii 5. The results show that important oenological characteristics of wine lactic acid bacteria, such as the malolactic activity and the production of volatile organic acids, may be differently affected by the presence of phenolic acids, depending on the bacterial species or strain.

  14. 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...... fermentation processes, but also for novel applications of lactic acid bacteria, such as cell factories for the production of green fuels and chemicals. With respect to the control and regulation of the fermentation mode, some progress has been made, but the question of which component(s) control the main...

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

    NARCIS (Netherlands)

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

    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 t

  16. 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 resul

  17. Lactic Acid Bateria - Friend or Foe? Lactic Acid Bacteria in the Production of Polysaccharides and Fuel Ethanol

    Science.gov (United States)

    Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating alpha-(1,6) and alpha-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, improved strains f...

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

    Directory of Open Access Journals (Sweden)

    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.

  19. [Systematic analysis and metabolic regulation of physiological functions for lactic acid bacteria--a review].

    Science.gov (United States)

    Wu, Chongde; Zhang, Juan; Liu, Liming

    2012-01-01

    As cell factories, lactic acid bacteria are widely used in food, agriculture, medicine and other industries, and play a great role in industrial processes. However, lactic acid bacteria encounter various environmental stresses both in industrial processes and in the gastrointestinal tract, which impair their physiological functions and food manufacture efficiency. Recently, the development of metabolic engineering and system biology brings unprecedented opportunity for the physiological modification of lactic acid bacteria. In this review, we addresses the progress of lactic acid bacterium system biology, and based on this, the metabolic engineering strategies for manipulating and optimizing lactic acid bacteria physiological function were summarized.

  20. Effect of monolaurin and lactic acid on Listeria monocytogenes attached to catfish fillets.

    Science.gov (United States)

    Verhaegh, E G; Marshall, D L; Oh, D H

    1996-04-01

    The purpose of this study was to determine the effects of monolaurin and lactic acid, singly or combined, on Listeria monocytogenes attached to catfish fillets. Skinless catfish fillets were inoculated with L. monocytogenes and dip treated in monolaurin and/or lactic acid solution for various time periods. Results showed that monolaurin up to 400 micrograms/ml had no influence on counts. Conversely, lactic acid-treated fillets had reduced counts compared to controls. Dipping in 0.85, 1.70, or 2.55% lactic acid for 30 min reduced counts by 0.9, 1.4, or 1.3 logs, respectively. Extending the dipping time to 60 min resulted in little additional decrease in counts. Combining monolaurin with lactic acid yielded results similar to lactic acid alone. Hence, population reduction ability resides with lactic acid and not monolaurin.

  1. Effect of Montmorillonite Clay upon the polycondensation of Lactic Acid

    Science.gov (United States)

    El Amine, Belaouedj Mohammed; Mohammed, Belbachir

    2008-08-01

    The development of synthetic biodegradable polymers, such as poly(α-hydroxy acid), is particularly important for constructing medical devices, drug delivery systems, including scaffolds and sutures, and has attracted growing interest in the biomedical field. Here, we report a novel approach to preparing poly(D, L-lactic acid) (PDLA) as a biodegradable polymer. We investigated in detail the reaction conditions for the simple direct polycondensation of lactic acid, including the reaction times, temperatures, and catalyst. The molecular weight of synthesized PLA is dependent on both the reaction temperature and time. The optimum reaction condition to obtain PDLA by direct polycondensation using Maghnite-H+, a proton exchanged Montmorillonite clay, as catalyst was thus determined to be 120 °C for 28h with a molecular weight of 7970. The method for PDLA synthesis established here will facilitate production of PDLA of various molecular weights, which may have a potential utility as biomaterials.

  2. ldentification and Mutagenesis of Lactic Acid Bacteria from Chinese Sauerkraut

    Institute of Scientific and Technical Information of China (English)

    Yajing CHAl; Hao SHl; Ri NA

    2015-01-01

    ln order to analyze the fermentation properties of lactic acid bacteria in Chinese sauerkraut and to improve acid production, 21 samples of Chinese sauerkraut from lnner Mongolia and Northeast China were col ected and isolated with a Man-Rogosa-Sharpe (MRS) culture. Sixteen strains of lactic acid bacteria were identified by combining both phenotype and genotype methods. After activation, the 16 strains were inoculated into the MRS medium with a concentration of 4%and then incubated at 37 ℃. The pH and the absorbance of the culture were mea-sured. The activated strains were then mutagenized in a field of 4 KV/cm mutation, with dosages administered within 20 minutes and 30 minutes, respectively. The variation curves of the pH and the absorbance of the culture were determined. The experimental results showed that the lactic acid bacteria isolated from the soup were identified as Lactobacil us and the acid production of the bacteria was signifi-cantly improved by the mutagenesis of the corona electric field.

  3. Lactic acid bacteria isolated from soy sauce mash in Thailand.

    Science.gov (United States)

    Tanasupawat, Somboon; Thongsanit, Jaruwan; Okada, Sanae; Komagata, Kazuo

    2002-08-01

    Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed.

  4. 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 <0.01 g ethanol/g xylose and 0.69 g lactic acid/g xylose, respectively. These results demonstrate that lactic acid can be produced from xylose with a high yield by S. cerevisiae without deleting pyruvate decarboxylase, and the formation patterns of fermentations can be altered by substrates.

  5. L-Lactic acid production from glycerol coupled with acetic acid metabolism by Enterococcus faecalis without carbon loss.

    Science.gov (United States)

    Murakami, Nao; Oba, Mana; Iwamoto, Mariko; Tashiro, Yukihiro; Noguchi, Takuya; Bonkohara, Kaori; Abdel-Rahman, Mohamed Ali; Zendo, Takeshi; Shimoda, Mitsuya; Sakai, Kenji; Sonomoto, Kenji

    2016-01-01

    Glycerol is a by-product in the biodiesel production process and considered as one of the prospective carbon sources for microbial fermentation including lactic acid fermentation, which has received considerable interest due to its potential application. Enterococcus faecalis isolated in our laboratory produced optically pure L-lactic acid from glycerol in the presence of acetic acid. Gas chromatography-mass spectrometry analysis using [1, 2-(13)C2] acetic acid proved that the E. faecalis strain QU 11 was capable of converting acetic acid to ethanol during lactic acid fermentation of glycerol. This indicated that strain QU 11 restored the redox balance by oxidizing excess NADH though acetic acid metabolism, during ethanol production, which resulted in lactic acid production from glycerol. The effects of pH control and substrate concentration on lactic acid fermentation were also investigated. Glycerol and acetic acid concentrations of 30 g/L and 10 g/L, respectively, were expected to be appropriate for lactic acid fermentation of glycerol by strain QU 11 at a pH of 6.5. Furthermore, fed-batch fermentation with 30 g/L glycerol and 10 g/L acetic acid wholly exhibited the best performance including lactic acid production (55.3 g/L), lactic acid yield (0.991 mol-lactic acid/mol-glycerol), total yield [1.08 mol-(lactic acid and ethanol)]/mol-(glycerol and acetic acid)], and total carbon yield [1.06 C-mol-(lactic acid and ethanol)/C-mol-(glycerol and acetic acid)] of lactic acid and ethanol. In summary, the strain QU 11 successfully produced lactic acid from glycerol with acetic acid metabolism, and an efficient fermentation system was established without carbon loss.

  6. Effects of Lactic Acid Bacteria Inoculated Fermentation on Pickled Cucumbers

    Directory of Open Access Journals (Sweden)

    Xiaoyi Ji

    2013-12-01

    Full Text Available The aim of this study was to determine the effects of Lactic Acid Bacteria (LAB fermentation on the texture and organic acid of pickled cucumbers. Texture and sensory evaluation as well as a microscopic observation were performed to study the textural differences among fresh cucumber, Spontaneous fermentation (SF cucumber and LAB Inoculating Fermentation (LABIF cucumber. Accumulation of seven organic acids i.e., oxalic, tartaric, malic, lactic, acetic, citric and succinic acid during cucumber pickling were also studied. The disruption extent of the middle lamella in SF cucumber displayed more obviously than that in LABIF cucumber, implying that LABIF contributed to keep the cucumber original structure intact. Based on the organic acid accumulation pattern, in SF LAB and Acetic Acid Bacteria (AAB fermented simultaneously, while in LABIF LAB fermented beforehand thus being in dominant position, then AAB fermented vigorously in a acidic condition created by LAB. The acetic acid accumulaton pattern could be regarded as the distinctive feature between SF and LABIF. The orgnic acids produced in LABIF were higher than that in SF. The final score of sensory evaluation combining texture analysis demonstrated that LABIF overmatched SF. It was concluded that LABIF could obviously enhance the quality of pickled cucumber and overwhelming SF, due to LABIF more beneficial to keep the cucumber original structure intact and organic acids accumulation.

  7. Functional fermented whey-based beverage using lactic acid bacteria.

    Science.gov (United States)

    Pescuma, Micaela; Hébert, Elvira María; Mozzi, Fernanda; de Valdez, Graciela Font

    2010-06-30

    Whey protein concentrate (WPC) is employed as functional food ingredient because of its nutritional value and emulsifying properties. However, the major whey protein beta-lactoglobulin (BLG) is the main cause of milk allergy. The aim of this study was to formulate a fermented whey beverage using selected lactic acid bacteria and WPC35 (WPC containing 35% of proteins) to obtain a fermented product with low lactose and BLG contents and high essential amino acid concentration. Cell viability, lactose consumption, lactic acid production, proteolytic activity, amino acid release and BLG degradation by the selected strains Lactobacillus acidophilus CRL 636, Lactobacillus delbrueckii subsp. bulgaricus CRL 656 and Streptococcus thermophilus CRL 804, as single or mixed (SLaB) cultures were evaluated in WPC35 (10%, w/v) incubated at 37 degrees C for 24h. Then, the fermented WPC35 was mixed with peach juice and calcium lactate (2%, w/v) and stored at 10 degrees C for 28 days. During fermentation, single cultures grew 1.7-3.1 log CFU/ml and produced 25.1-95.0 mmol/l of lactic acid as consequence of lactose consumption (14.0-41.8 mmol/l) after 12h fermentation. L. delbrueckii subsp. bulgaricus CRL 656 was the most proteolytic strain (626 microg/ml Leu) and released the branched-chain essential amino acids Leu (16 microg/ml), Ile (27 microg/ml) and Val (43 microg/ml). All strains were able to degrade BLG in a range of 41-85% after 12h incubation. The starter culture SLaB grew 3.0 log CFU/ml, showed marked pH reduction, produced 122.0 mmol/l of lactic acid, displayed high proteolytic activity (484 microg/ml Leu) releasing Leu (13 microg/ml), Ile (18 microg/ml) and Val (35 microg/ml), and hydrolyzed 92% of BLG. The addition of calcium lactate to WPC35 maintained the drink pH stable during shelf life; no contamination was detected during this period. After 28 days, a decrease in cell viability of all strains was observed being more pronounced for L. delbrueckii subsp. bulgaricus

  8. Lactic acid fermentation by cells immobilised on various porous cellulosic materials and their alginate/poly-lactic acid composites.

    Science.gov (United States)

    Kumar, Mrinal Nishant; Gialleli, Angelika-Ioanna; Masson, Jean Bernard; Kandylis, Panagiotis; Bekatorou, Argyro; Koutinas, Athanasios A; Kanellaki, Maria

    2014-08-01

    Porous delignified cellulose (or tubular cellulose, abbr. TC) from Indian Mango (Mangifera indica) and Sal (Shorea robusta) wood and Rice husk, and TC/Ca-alginate/polylactic acid composites, were used as Lactobacillus bulgaricus immobilisation carriers leading to improvements in lactic acid fermentation of cheese whey and synthetic lactose media, compared to free cells. Specifically, shorter fermentation rates, higher lactic acid yields (g/g sugar utilised) and productivities (g/Ld), and higher amounts of volatile by-products were achieved, while no significant differences were observed on the performance of the different immobilised biocatalysts. The proposed biocatalysts are of food grade purity, cheap and easy to prepare, and they are attractive for bioprocess development based on immobilised cells. Such composite biocatalysts may be used for the co-immobilisation of different microorganisms or enzymes (in separate layers of the biocatalyst), to efficiently conduct different types of fermentations in the same bioreactor, avoiding inhibition problems of chemical or biological (competition) nature.

  9. Crystallization kinetics of poly(lactic acid-talc composites

    Directory of Open Access Journals (Sweden)

    2011-10-01

    Full Text Available The crystallization kinetics of poly(lactic acid / talc composites were determined over a range of 0 to 15 wt% of talc. Talc was found to change the crystallization kinetics. The presence of talc increases the crystallization rate and this increase is related to talc concentration and to crystallization temperature. In order to understand the effect of talc and PLA crystallinity on mechanical properties, dynamic mechanical thermal analyses were performed on poly(lactic acid / talc composites before and after an annealing process. It was demonstrated that the presence of crystals improves thermomechanical properties but in order to achieve good results at high temperatures the reinforcing effect of a filler such as talc is necessary.

  10. Bacteriocins of lactic acid bacteria: extending the family.

    Science.gov (United States)

    Alvarez-Sieiro, Patricia; Montalbán-López, Manuel; Mu, Dongdong; Kuipers, Oscar P

    2016-04-01

    Lactic acid bacteria (LAB) constitute a heterogeneous group of microorganisms that produce lactic acid as the major product during the fermentation process. LAB are Gram-positive bacteria with great biotechnological potential in the food industry. They can produce bacteriocins, which are proteinaceous antimicrobial molecules with a diverse genetic origin, posttranslationally modified or not, that can help the producer organism to outcompete other bacterial species. In this review, we focus on the various types of bacteriocins that can be found in LAB and the organization and regulation of the gene clusters responsible for their production and biosynthesis, and consider the food applications of the prototype bacteriocins from LAB. Furthermore, we propose a revised classification of bacteriocins that can accommodate the increasing number of classes reported over the last years.

  11. 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.

  12. Optimization of (-galactosidase production from lactic acid bacteria

    OpenAIRE

    2015-01-01

    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 yi...

  13. Role of inorganic carbon in lactic acid bacteria metabolism

    OpenAIRE

    Arsène-Ploetze, Florence; Bringel, Françoise

    2004-01-01

    International audience; Capnophiles are bacteria stimulated by bicarbonate and CO$_2$, the two major forms of inorganic carbon (IC) in physiological neutral liquids. Capnophiles are often pathogenic heterotrophs found in IC-rich ecological niches such as human cavities. Like capnophiles, the growth of lactic acid bacteria (LAB) such as Lactobacillus plantarum and Enterococcus faecalis is stimulated by IC. CO$_2$ or HCO$^{-}_3$ are substrates in carbamoyl phosphate (CP) synthesis and other car...

  14. RECOVERY OF LACTIC ACID FROM AMERICAN CRYSTAL SUGAR COMPANY WASTEWATER

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-04-30

    This project has shown that the recovery of several valuable lactic acid products is both technically feasible and economically viable. One of the original objectives of this project was to recover lactic acid. However, the presence of a variety of indigenous bacteria in the wastewater stream and technical issues related to recovery and purification have resulted in the production of lactic acid esters. These esters could by hydrolyzed to lactic acid, but only with unacceptable product losses that would be economically prohibitive. The developed process is projected to produce approximately 200,000 lb per day of lactate esters from wastewater at a single factory at costs that compete with conventional solvents. The lactate esters are good solvents for polymers and resins and could replace acetone, methyl ethyl ketone, MIBK, and other polar solvents used in the polymer industry. Because of their low volatility and viscosity-lowering properties, they will be especially useful for inks for jet printers, alkyl resins, and high-solid paints. Owing to their efficiency in dissolving salts and flux as well as oils and sealants, lactate esters can be used in cleaning circuit boards and machine and engine parts. Unlike conventional solvents, lactate esters exhibit low toxicity, are biodegradable, and are not hazardous air pollutants. Another application for lactate esters is in the production of plasticizers. Severe health problems have been attributed to widely used phthalate ester plasticizers. The U.S. Department of Agriculture showed that replacement of these with inexpensive lactate esters is feasible, owing to their superior polymer compatibility properties. A very large market is projected for polymers prepared from lactic acid. These are called polylactides and are a type of polyester. Thermoplastics of this type have a variety of uses, including moldings, fibers, films, and packaging of both manufactured goods and food products. Polylactides form tough, orientable

  15. 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

  16. 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 re

  17. Effect of 82% Lactic Acid in Treatment of Melasma

    Science.gov (United States)

    Singh, Rashmi; Goyal, Sapna; Ahmed, Qazi Rais; Gupta, Narendra; Singh, Sujata

    2014-01-01

    Melasma is an acquired, chronic, and symmetrical hypermelanosis, characterized by brown patches of variable darkness on sun exposed areas of body. There are numerous modalities of treatment currently in use for this disease, of which the chemical peeling is very commonly used. Therefore, the present work was done to see the effect of 82% lactic acid peel in the treatment of melasma. A total number of 20 patients of either sex attending the OPD of dermatology department with clinically evident melasma were included in the study. 82% Lactic acid peel was applied on the face for 12 weeks in each patient. Patients were evaluated clinically and photographically at various intervals and in follow-up till 24 weeks. Assessment of patient satisfaction and side effects were also noted. All the subjects completed the study. Application of this peel for 12 weeks significantly decreased the melasma area severity index score and also melasma severity scale score. Patient and physician analogue scales also showed the improvement by the treatment. Regarding the adverse effects, burning sensation was the only side effect noted in our study. In conclusion, 82% lactic acid peel is well tolerated and can be used for the treatment of melasma. PMID:27355080

  18. Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

    Directory of Open Access Journals (Sweden)

    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.

  19. 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.

  20. Technology and economic assessment of lactic acid production and uses

    Energy Technology Data Exchange (ETDEWEB)

    Datta, R.; Tsai, S.P.

    1996-03-01

    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}50,000 tons/yr) used in a wide range of food-processing and industrial applications. Potentially, it can become a very large-volume, commodity-chemical intermediate produced from carbohydrates for feedstocks of biodegradable polymers, oxygenated chemicals, environmentally friendly ``green`` solvents, and other intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from fermentation broths and its conversion to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. Development and deployment of novel separations technologies, such as electrodialysis with bipolar membranes, extractive and catalytic distillations, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The emerging technologies can use environmentally sound lactic acid processes to produce environmentally useful products, with attractive process economics. These technology advances and recent product and process commercialization strategies are reviewed and assessed.

  1. Lactic acid bacteria as a cell factory for riboflavin production

    Science.gov (United States)

    Thakur, Kiran; De, Sachinandan

    2015-01-01

    Summary 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. PMID:26686515

  2. Lactic acid recovery from cheese whey fermentation broth using combined ultrafiltration and nanofiltration membranes.

    Science.gov (United States)

    Li, Yebo; Shahbazi, Abolghasem

    2006-01-01

    The separation of lactic acid from lactose in the ultrafiltration permeate of cheese whey broth was studied using a cross-flow nanofiltration membrane unit. Experiments to test lactic acid recovery were conducted at three levels of pressure (1.4, 2.1, and 2.8 MPa), two levels of initial lactic acid concentration (18.6 and 27 g/L), and two types of nanofiltration membranes (DS-5DK and DS-5HL). Higher pressure caused significantly higher permeate flux and higher lactose and lactic acid retention (p < 0.0001). Higher initial lactic acid concentrations also caused significantly higher permeate flux, but significantly lower lactose and lactic acid retention (p < 0.0001). The two tested membranes demonstrated significant differences on the permeate flux and lactose and lactic acid retention. Membrane DS-5DK was found to retain 100% of lactose at an initial lactic acid concentration of 18.6 g/L for all the tested pressures, and had a retention level of 99.5% of lactose at initial lactic acid concentration of 27 g/L when the pressure reached 2.8 MPa. For all the tests when lactose retention reached 99-100%, as much as 64% of the lactic acid could be recovered in the permeate.

  3. Production of D-lactic acid by bacterial fermentation of rice starch.

    Science.gov (United States)

    Fukushima, Kazuki; Sogo, Kazuaki; Miura, Shigenobu; Kimura, Yoshiharu

    2004-11-20

    D-Lactic acid was synthesized by the fermentation of rice starch using microorganisms. Two species: Lactobacillus delbrueckii and Sporolactobacillus inulinus were found to be active in producing D-lactic acid of high optical purity after an intensive screening test for D-lactic acid bacteria using glucose as substrate. Rice powder used as the starch source was hydrolyzed with a combination of enzymes: alpha-amylase, beta-amylase, and pullulanase to obtain rice saccharificate consisting of maltose as the main component. Its average gross yield was 82.5%. Of the discovered D-lactic acid bacteria, only Lactobacillus delbrueckii could ferment both maltose and the rice saccharificate. After optimizing the fermentation of the rice saccharificate using this bacterium, pilot scale fermentation was conducted to convert the rice saccharificate into D-lactic acid with a D-content higher than 97.5% in a yield of 70%. With this yield, the total yield of D-lactic acid from brown rice was estimated to be 47%, which is almost equal to the L-lactic acid yield from corn. The efficient synthesis of D-lactic acid can open a way to the large scale application of high-melting poly(lactic acid) that is a stereocomplex of poly(L-lactide) and poly(D-lactide). Schematic representation of the production of D-lactic acid starting from brown rice as described here.

  4. Evaluation of different lactic acid bacterial strains for probiotic characteristics

    Directory of Open Access Journals (Sweden)

    B. Srinu,

    2013-08-01

    Full Text Available 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 discs on de Mann Rogosa Sharpe broth (MRS agar plates seeded with the test probiotic organism. The antibacterial activity of LAB was assessed by using well diffusion method.Results: Among the six probiotic strains tested, all showed good survivability at high bile salt concentration (0.3 to 2.0 % oxgall and good growth at a low pH of 1.5 to 3.5. These probiotic species showed good survival abilities in acidic pH of 2.0 to 3.5 except Lactobacillus delbrueckii subspp. bulgaricus 281 which did not grown at pH of 2.0. Lactobacillus fermentum 141 was able to grow even at pH of 1.5 also. Among the six lactic acid species, Lactobacillus fermentum 141 (except Tetracycline, Lactobacillus delbrueckii subspp. Bulgaricus 281 except (Cefpodoxime and all other LAB were resistant to all the antibiotics tested (Ampicillin, Nalidixic acid , Ciprofloxacin ,Co-Trimoxazole, Gentamicin and Cefpodoxime. All these probiotic organisms were screened for their in vitro inhibition ability against pathogenic microorganisms namely, E.coli ATCC (American type culture collection centre, Pseudomonas aeruginosa, Salmonella paratyphi, Staphylococcus aureus. Lactobacillus delbrueckii subspp. bulgaricus 281, Lactobacillus casei 297 and Lactobacillus fermentum 141 inhibited the growth of all the pathogenic bacteria used in the study. Conclusion: The study indicated Lactobacillus fermentum 141 and Lactobacillus casei 297 as potential functional probiotics for future in vivo studies for

  5. Influence of temperature on production of lactic acid from kitchen garbage

    Institute of Scientific and Technical Information of China (English)

    汪群慧; 徐忠; 孟令辉; 孙晓红; 王旭明

    2003-01-01

    The production of lactic acid from kitchen garbage, the precursor for production of biodegradableplastics is described in detail. The influence of temperature on the lactic acid concentration, sugar concentra-tion, and decrement of garbage were evaluated through experiments. Fermentation were carried out in an incu-bator at 5, 25, 37 and 50 ℃. The latic acid produced was maximum at initial pH 6.0 and 37 ℃ , i.e. 38 g/Lwith a yield of 0.23 g/gVS. It is concluded from the experimental results that temperature has quite a consider-able effect on the production of lactic acid; lactic acid concentration increases with temperature until 37 ℃ ,and production rate of lactic acid drops at 50 ℃; the optimal fermentation is 37 ℃. This study shows that pro-duction of lactic acid from kitchen garbage is feasible and reduction of garbage can be realized.

  6. Improvement of L: -Lactic Acid Production under Glucose Feedback Controlled Culture by Lactobacillus rhamnosus.

    Science.gov (United States)

    Li, Zheng; Lu, JiKe; Zhao, Liqiang; Xiao, Kai; Tan, Tianwei

    2010-11-01

    In this study, a glucose feedback controller had been designed. Under the controller, the glucose concentration in l-lactic acid culture could be automatically controlled at 15 ± 1 g/L. Furthermore, l-lactic acid production by Lactobacillus rhamnosus LA-04-1 in fed-batch culture was significantly increased to 170 g/L l-lactic acid using the controller compared with 130 g/L l-lactic acid in pulse fed-batch and 135 g/L in l-lactic acid constant feed rate fed-batch cultures. The results showed that the controller was effective at glucose control in l-lactic acid culture. The control strategy could also be used in other fermentation processes.

  7. Lactic acid production by mixed cultures of Kluyveromyces marxianus, Lactobacillus delbrueckii ssp. bulgaricus and Lactobacillus helveticus.

    Science.gov (United States)

    Plessas, S; Bosnea, L; Psarianos, C; Koutinas, A A; Marchant, R; Banat, I M

    2008-09-01

    Lactic acid production using Kluyveromyces marxianus (IFO 288), Lactobacillus delbrueckii ssp. bulgaricus (ATCC 11842) and Lactobacillus helveticus (ATCC 15009) individually or as mixed culture on cheese whey in stirred or static fermentation conditions was evaluated. Lactic acid production, residual sugar and cell biomass were the main features examined. Increased lactic acid production was observed, when mixed cultures were used in comparison to individual ones. The highest lactic acid concentrations were achieved when K. marxianus yeast was combined with L. delbrueckii ssp. bulgaricus, and when all the strains were used revealing possible synergistic effects between the yeast and the two lactic acid bacteria. The same synergistic effects were further observed and verified when the mixed cultures were applied in sourdough fermentations, proving that the above microbiological system could be applied in the food fermentations where high lactic acid production is sought.

  8. Lactic acid demineralization of shrimp shell and chitosan synthesis

    Directory of Open Access Journals (Sweden)

    Alewo Opuada AMEH

    2015-05-01

    Full Text Available The use of lactic acid was compared to hydrochloric acid for shrimp shell demineralization in chitosan synthesis. Five different acid concentrations were considered for the study: 1.5M, 3.0M, 4.5M, 6.0M and 7.5M. After demineralization, the shrimp shell were deproteinized and subsequently deacetylated to produce chitosan using sodium hydroxide solution. The synthesized chitosan samples were characterized using solubility, FTIR, SEM, XRD and viscosity. The SEM, FTIR and XRD analysis indicated that chitosan was synthesized with a high degree of deacetylation (83.18±2.11 when lactic acid was used and 84.2±5.00 when HCl was used. The degree of deacetylation and the molecular weight of the chitosan samples were also estimated. ANOVA analysis (at 95% confidence interval indicated that acid type and concentration did not significantly affect the solubility, degree of deacetylation, viscosity and molecular weight of the chitosan within the range considered.

  9. A study of parameters affecting the solvent extraction of lactic acid from fermentation broth

    OpenAIRE

    Udachan,I. S.; Sahoo, A.K.

    2014-01-01

    Lactic acid has recently been drawing much interest as a raw material for biodegradable polymer. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid - liquid extraction. Equilibrium studies on the reactive extraction of lactic acid with trioctylamine (TOA) in various organic phases and its re-extraction into aqueous solutions were carried out. In this study distribution coefficient, extractability, stripping efficiency of various active and...

  10. Mechanism of Synergistic Inhibition of Listeria monocytogenes Growth by Lactic Acid, Monolaurin, and Nisin▿

    OpenAIRE

    Tokarskyy, Oleksandr; Marshall, Douglas L.

    2008-01-01

    The combined lactic acid, monolaurin, and nisin effects on time-to-detection (optical density at 600 nm) extension were greater (P < 0.05) than any single or paired combination effect, which demonstrates a synergistic interaction among the antimicrobials. Monolaurin exposure caused C12:0 cell membrane incorporation. Lactic acid caused increased monolaurin C12:0 membrane incorporation, while nisin had no influence. We postulate that lactic acid-enhanced monolaurin C12:0 incorporation into the ...

  11. Mechanism of synergistic inhibition of Listeria monocytogenes growth by lactic acid, monolaurin, and nisin.

    Science.gov (United States)

    Tokarskyy, Oleksandr; Marshall, Douglas L

    2008-12-01

    The combined lactic acid, monolaurin, and nisin effects on time-to-detection (optical density at 600 nm) extension were greater (P Monolaurin exposure caused C12:0 cell membrane incorporation. Lactic acid caused increased monolaurin C12:0 membrane incorporation, while nisin had no influence. We postulate that lactic acid-enhanced monolaurin C12:0 incorporation into the cell membrane increased membrane fluidity resulting in increased nisin activity.

  12. Mechanism of Synergistic Inhibition of Listeria monocytogenes Growth by Lactic Acid, Monolaurin, and Nisin▿

    Science.gov (United States)

    Tokarskyy, Oleksandr; Marshall, Douglas L.

    2008-01-01

    The combined lactic acid, monolaurin, and nisin effects on time-to-detection (optical density at 600 nm) extension were greater (P Monolaurin exposure caused C12:0 cell membrane incorporation. Lactic acid caused increased monolaurin C12:0 membrane incorporation, while nisin had no influence. We postulate that lactic acid-enhanced monolaurin C12:0 incorporation into the cell membrane increased membrane fluidity resulting in increased nisin activity. PMID:18820062

  13. Lactic-acid stress causes vacuolar fragmentation and impairs intracellular amino-acid homeostasis in Saccharomyces cerevisiae.

    Science.gov (United States)

    Suzuki, Toshihiro; Sugiyama, Minetaka; Wakazono, Kenta; Kaneko, Yoshinobu; Harashima, Satoshi

    2012-04-01

    To gain more insight into adaptation response to lactic-acid stress in yeast, a genome-wide screening for genes whose disruption caused hypersensitivity to 4.0% l-lactic acid (pH 2.8) was performed using the gene deletion collection of Saccharomyces cerevisiae. We identified 107 genes that contributed significantly to the ability of yeast cells to adapt lactic-acid stress. More than 30% of the genes identified in this screening were newly identified to be involved in mechanisms for adaptation response to lactic acid. We found that protein urmylation by Uba4 and N-terminal acetylation by Nat3 were involved in lactic acid adaptation mechanisms. Functional categorization of the genes followed by microscopic analysis revealed that a variety of cellular functions were involved in adaptation response to lactic acid and function associated with vacuolar transport played important roles in adaptation response to lactic acid. We also found that vacuole fragmented immediately upon exposure to lactic- and hydrochloric-acid stress. In addition, our analysis revealed that lactic-acid stress significantly reduced the amount of intracellular amino acids. Amino acid supplementation recovered the adaptation deficiency to lactic acid, suggesting that intracellular amino-acid homeostasis plays important roles in adaptation response to lactic-acid stress. These data suggest that enhancing vacuolar integrity, as well as maintaining intracellular amino-acid homeostasis may be an efficient approach to confer resistance to lactic-acid stress. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Genotypic characterization and safety assessment of lactic acid bacteria from indigenous African fermented food products

    National Research Council Canada - National Science Library

    Adimpong, David B; Nielsen, Dennis S; Sørensen, Kim I; Derkx, Patrick M F; Jespersen, Lene

    2012-01-01

    .... Lactic acid bacteria (LAB) are among the predominant microbial species in African indigenous fermented food products and are used for different applications in the food and biotechnology industries...

  16. The Promotion of Erythropoiesis via the Regulation of Reactive Oxygen Species by Lactic Acid.

    Science.gov (United States)

    Luo, Shun-Tao; Zhang, Dong-Mei; Qin, Qing; Lu, Lian; Luo, Min; Guo, Fu-Chun; Shi, Hua-Shan; Jiang, Li; Shao, Bin; Li, Meng; Yang, Han-Shuo; Wei, Yu-Quan

    2017-02-06

    The simultaneous increases in blood lactic acid and erythrocytes after intense exercise could suggest a link between lactate and the erythropoiesis. However, the effects of lactic acid on erythropoiesis remain to be elucidated. Here, we utilized a mouse model to determine the role of lactic acid in this process in parallel with studies using leukaemic K562 cells. Treatment of K562 cells in vitro with lactic acid increased the mRNA and protein expression of haemoglobin genes and the frequency of GPA(+) cells. Also, increases in haematocrit and CD71(-)/Ter119(+) erythroid cells were observed in lactic acid-treated mice, which showed a physiological increase in blood lactate. Mouse bone marrow CD34(+)/CD117(-) cells showed an increase in erythroid burst-forming units after stimulation with lactic acid in vitro. Furthermore, lactic acid increased the intracellular reactive oxygen species (ROS) content in bone marrow and in K562 cells. Erythroid differentiation induced in Haematopoietic Stem Cells (HSCs) and K562 cells by lactic acid was abolished by reducing ROS levels with SOD or 2-mercaptoethanol, which suggests that ROS is a critical regulator of this process. These findings provide a better understanding of the role of lactic acid in cellular metabolism and physiological functions.

  17. An integrated bioconversion process for the production of L-lactic acid from starchy feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, S.P.; Moon, S.H.

    1997-07-01

    The potential market for lactic acid as the feedstock for biodegradable polymers, oxygenated chemicals, and specialty chemicals is significant. L-lactic acid is often the desired enantiomer for such applications. However, stereospecific lactobacilli do not metabolize starch efficiently. In this work, Argonne researchers have developed a process to convert starchy feedstocks into L-lactic acid. The processing steps include starch recovery, continuous liquefaction, and simultaneous saccharification and fermentation. Over 100 g/L of lactic acid was produced in less than 48 h. The optical purity of the product was greater than 95%. This process has potential economical advantages over the conventional process.

  18. POTENTIAL OF CEREALS AND PSEUDOCEREALS FOR LACTIC ACID FERMENTATIONS

    Directory of Open Access Journals (Sweden)

    Ľubomír Valík

    2011-04-01

    Full Text Available Cereals and pseudocereals play a significant role in human nutrition. They are source of specific carbohydrates, proteins, lipids, fibre and wide spectrum of vitamins and minerals. Moreover, pseudocereals have a higher content of essential amino acids, e.g. lysine and tryptophan. Cereals and pseudocereals may also contain some antinutrition factors, such as phytic acid, polyphenols, trypsin inhibitors and inhibitors of α-amylase. These are responsible for reducing of protein and carbohydrate digestibility and decreasing accessibility of minerals due to complex formation. This review assesses the applications of cereals and pseudocereals in fermentation technology including the effects of lactic acid bacteria on nutrition, sensory quality and shelf-life. This work is focusing also on fermentation process of cereal matrice leading in degradation of antinutritional factors increase of nutritional value and availability of minerals, proteins and carbohydrates. Lactic acid bacteria produce many aromatic compounds that are beneficial to organoleptic atributes of the products. However, a few questions have been not answered in experiments, yet. For eample, is there any space for evaluation of their suitability to act as carriers of probiotics? Could such the attempts lead in development some special formulae suitable for consumers with food allergies or deficiencies?doi:10.5219/127

  19. COMPARISON OF OCCURENCE LACTIC ACID BACTERIA IN CHOSEN YOGURTS

    Directory of Open Access Journals (Sweden)

    Silvia Pinterová

    2010-11-01

    Full Text Available The yogurt is healthy food, which contains at least 100 million cultures per gram. Probiotic bacteria have been proven to reduce the effects of some gastrointestinal problems, probiotics can greatly reduce lactose intolerance, have also been proven to prevent colon cancers, there are also a natural immune system booster. In our research we detected numbers of lactid acid bacteria in yogurts in slovak market. There were classical yogurts, yogurts with probiotics, yogurts with fat and non fat. We numbered lactid acid bacteria from and after expiration, in agars MRS and Lee´s. In examined yogurts we detected from expiration from 78.107  to 169.107  and after expiration from 59.107 to 133.107 lactic acid bacteria in 1 ml of yogurt. In agreement with Food Codex of SR (2010 of rules all these yogurts satisfy number of lactid acid bacteria. doi:10.5219/31

  20. The proteolytic system of lactic acid bacteria revisited : a genomic comparison

    NARCIS (Netherlands)

    Liu, M.; Bayjanov, J.; Renckens, B.A.M.; Nauta, A.; Siezen, R.J.

    2010-01-01

    BACKGROUND: Lactic acid bacteria (LAB) are a group of gram-positive, lactic acid producing Firmicutes. They have been extensively used in food fermentations, including the production of various dairy products. The proteolytic system of LAB converts proteins to peptides and then to amino acids, which

  1. The Optimized Synthesis of Starch-g-Lactic Acid Copolymer with High Grafting Degree Catalyzed by Sulfuric Acid

    Institute of Scientific and Technical Information of China (English)

    HU Zhiying

    2014-01-01

    The starch-g-lactic acid copolymer was synthesized with catalysis of sulfuric acid by one-step process, and the structure of starch-g-lactic acid copolymer was characterized by means of IR, 13C-NMR, HMBC, XRD, and SEM. The experimental results show that the maximum grafting degree of starch can reach 75%when the starch-g-lactic acid copolymer is activated at 80℃for 2 h and reacted with lactic acid at 90℃for 4 h in vacuum.

  2. Lactic acid bacteria: the bugs of the new millennium.

    Science.gov (United States)

    Konings, W N; Kok, J; Kuipers, O P; Poolman, B

    2000-06-01

    Lactic acid bacteria (LABs) are widely used in the manufacturing of fermented food and are among the best-studied microorganisms. Detailed knowledge of a number of physiological traits has opened new potential applications for these organisms in the food industry, while other traits might be beneficial for human health. Important new developments have been made in the research of LABs in the areas of multidrug resistance, bacteriocins and quorum sensing, osmoregulation, proteolysis, autolysins and bacteriophages. Recently, progress has been made in the construction of food-grade genetically modified LABs.

  3. Interaction effects of lactic acid and acetic acid at different temperatures on ethanol production by Saccharomyces cerevisiae in corn mash.

    Science.gov (United States)

    Graves, Tara; Narendranath, Neelakantam V; Dawson, Karl; Power, Ronan

    2007-01-01

    The combined effects of lactic acid and acetic acid on ethanol production by S. cerevisiae in corn mash, as influenced by temperature, were examined. Duplicate full factorial experiments (three lactic acid concentrations x three acetic acid concentrations) were performed to evaluate the interaction between lactic and acetic acids on the ethanol production of yeast at each of the three temperatures, 30, 34, and 37 degrees C. Corn mash at 30% dry solids adjusted to pH 4 after lactic and acetic acid addition was used as the substrate. Ethanol production rates and final ethanol concentrations decreased (Plactic and acetic acids in the corn mash increased and the temperature was raised from 30 to 37 degrees C. At 30 degrees C, essentially no ethanol was produced after 96 h when 0.5% w/v acetic acid was present in the mash (with 0.5, 2, and 4% w/v lactic acid). At 34 and 37 degrees C, the final concentrations of ethanol produced by the yeast were noticeably reduced by the presence of 0.3% w/v acetic acid and >or=2% w/v lactic acid. It can be concluded that, as in previous studies with defined media, lactic acid and acetic acid act synergistically to reduce ethanol production by yeast in corn mash. In addition, the inhibitory effects of combined lactic and acetic acid in corn mash were more apparent at elevated temperatures.

  4. Cyclic Comonomers for the Synthesis of Carboxylic Acid and Amine Functionalized Poly(l-Lactic Acid

    Directory of Open Access Journals (Sweden)

    Markus Heiny

    2015-03-01

    Full Text Available Degradable aliphatic polyesters such as poly(lactic acid are widely used in biomedical applications, however, they lack functional moieties along the polymer backbone that are amenable for functionalization reactions or could be the basis for interactions with biological systems. Here we present a straightforward route for the synthesis of functional α-ω epoxyesters as comonomers for lactide polymerization. Salient features of these highly functionalized epoxides are versatility in functionality and a short synthetic route of less than four steps. The α-ω epoxyesters presented serve as a means to introduce carboxylic acid and amine functional groups into poly(lactic acid polymers via ring-opening copolymerization.

  5. Bioprotective potential of lactic acid bacteria in malting and brewing.

    Science.gov (United States)

    Rouse, Susan; van Sinderen, Douwe

    2008-08-01

    Lactic acid bacteria (LAB) are naturally associated with many foods or their raw ingredients and are popularly used in food fermentation to enhance the sensory, aromatic, and textural properties of food. These microorganisms are well recognized for their biopreservative properties, which are achieved through the production of antimicrobial compounds such as lactic acid, diacetyl, bacteriocins, and other metabolites. The antifungal activity of certain LAB is less well characterized, but organic acids, as yet uncharacterized proteinaceous compounds, and cyclic dipeptides can inhibit the growth of some fungi. A variety of microbes are carried on raw materials used in beer brewing, rendering the process susceptible to contamination and often resulting in spoilage or inferior quality of the finished product. The application of antimicrobial-producing LAB at various points in the malting and brewing process could help to negate this problem, providing an added hurdle for spoilage organisms to overcome and leading to the production of a higher quality beer. This review outlines the bioprotective potential of LAB and its application with specific reference to the brewing industry.

  6. Safety evaluation of poly(lactic-co-glycolic acid)/poly(lactic-acid) microspheres through intravitreal injection in rabbits.

    Science.gov (United States)

    Rong, Xianfang; Yuan, Weien; Lu, Yi; Mo, Xiaofen

    2014-01-01

    Poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic-acid) (PLA) microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of PLGA/PLA microspheres through intravitreal injection in rabbits. Normal New Zealand rabbits were randomly selected and received intravitreal administration of different doses (low, medium, or high) of PLGA/PLA microspheres and erythropoietin-loaded PLGA/PLA microspheres. The animals were clinically examined and sacrificed at 1, 2, 4, 8, and 12 weeks postadministration, and retinal tissues were prepared for analysis. Retinal reactions to the microspheres were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end staining and glial fibrillary acidic protein immunohistochemistry. Retinal structure changes were assessed by hematoxylin and eosin staining and transmission electron microscopy. Finally, retinal function influences were explored by the electroretinography test. Terminal deoxynucleotidyl transferase-mediated dUTP nick end staining revealed no apoptotic cells in the injected retinas; immunohistochemistry did not detect any increased glial fibrillary acidic protein expression. Hematoxylin and eosin staining and transmission electron microscopy revealed no micro- or ultrastructure changes in the retinas at different time points postintravitreal injection. The electroretinography test showed no significant influence of scotopic or photopic amplitudes. The results demonstrated that PLGA/PLA microspheres did not cause retinal histological changes or functional damage and were biocompatible and safe enough for intravitreal injection in rabbits for controlled drug delivery.

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

    Science.gov (United States)

    Gong, Zheng; Tang, M Matt; Wu, Xueliang; Phillips, Nancy; Galkowski, Dariusz; Jarvis, Gary A; Fan, Huizhou

    2016-01-01

    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.

  8. 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.

  9. 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.

  10. d-lactic acid production from renewable lignocellulosic biomass via genetically modified Lactobacillus plantarum.

    Science.gov (United States)

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

    2016-03-01

    d-lactic acid is of great interest because of increasing demand for biobased poly-lactic acid (PLA). Blending poly-l-lactic acid with poly-d-lactic acid greatly improves PLA's mechanical and physical properties. Corn stover and sorghum stalks treated with 1% sodium hydroxide were investigated as possible substrates for d-lactic acid production by both sequential saccharification and fermentation and simultaneous saccharification and cofermentation (SSCF). A commercial cellulase (Cellic CTec2) was used for hydrolysis of lignocellulosic biomass and an l-lactate-deficient mutant strain Lactobacillus plantarum NCIMB 8826 ldhL1 and its derivative harboring a xylose assimilation plasmid (ΔldhL1-pCU-PxylAB) were used for fermentation. The SSCF process demonstrated the advantage of avoiding feedback inhibition of released sugars from lignocellulosic biomass, thus significantly improving d-lactic acid yield and productivity. d-lactic acid (27.3 g L(-1) ) and productivity (0.75 g L(-1) h(-1) ) was obtained from corn stover and d-lactic acid (22.0 g L(-1) ) and productivity (0.65 g L(-1) h(-1) ) was obtained from sorghum stalks using ΔldhL1-pCU-PxylAB via the SSCF process. The recombinant strain produced a higher concentration of d-lactic acid than the mutant strain by using the xylose present in lignocellulosic biomass. Our findings demonstrate the potential of using renewable lignocellulosic biomass as an alternative to conventional feedstocks with metabolically engineered lactic acid bacteria to produce d-lactic acid. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:271-278, 2016.

  11. Lipase catalyzed synthesis of organic acid esters of lactic acid in non-aqueous media.

    Science.gov (United States)

    Kiran, K R; Divakar, S

    2001-05-04

    Lipases from Rhizomucor miehei (Lipozyme IM20) and porcine pancreas (PPL) were employed as catalysts for the esterification reaction between the hydroxyl group of lactic acid and the carboxyl group of organic acids. Reactions were carried out at both shake-flask and bench-scale levels. Various parameters, such as solvent, temperature, substrate and enzyme concentrations, effect of buffer volume, buffer pH and water volume, were investigated for optimization of yields. While ethylmethyl ketone (EMK) was found to be the best solvent for shake-flask reactions, chloroform gave higher yields at bench-scale level. Detailed studies were carried out with respect to the synthesis of palmitoyl and stearoyl lactic acids. At shake-flask level, maximum yields of 37.5 and 40% were observed in case of palmitoyl and stearoyl lactic acids, respectively, with Lipozyme IM20; at bench-scale level, the maximum yields were 85.1 and 99% respectively, when PPL was employed. Of all the organic acids employed (C(2)--C(18)), only lauric, palmitic and stearic acids gave yields above 50%. At bench-scale level, PPL could be reused for up to three cycles with yields above 40%. Esters prepared were found to conform to Food Chemical Codex (FCC) specifications in terms of acid value, ester value, sodium and lactic acid contents.

  12. Comparative functional genomics of amino acid metabolism of lactic acid bacteria

    NARCIS (Netherlands)

    Pastink, M.I.

    2009-01-01

    The amino acid metabolism of lactic acid bacteria used as starters in industrial fermentations has profound effects on the quality of the fermented foods. The work described in this PhD thesis was initiated to use genomics technologies and a comparative approach to link the gene content of some well

  13. Phenolic biotransformations during conversion of ferulic acid to vanillin by lactic acid bacteria.

    Science.gov (United States)

    Kaur, Baljinder; Chakraborty, Debkumar; Kumar, Balvir

    2013-01-01

    Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB), and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

  14. Phenolic Biotransformations during Conversion of Ferulic Acid to Vanillin by Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Baljinder Kaur

    2013-01-01

    Full Text Available Vanillin is widely used as food additive and as a masking agent in various pharmaceutical formulations. Ferulic acid is an important precursor of vanillin that is available in abundance in cell walls of cereals like wheat, corn, and rice. Phenolic biotransformations can occur during growth of lactic acid bacteria (LAB, and their production can be made feasible using specialized LAB strains that have been reported to produce ferulic acid esterases. The present study aimed at screening a panel of LAB isolates for their ability to release phenolics from agrowaste materials like rice bran and their biotransformation to industrially important compounds such as ferulic acid, 4-ethyl phenol, vanillic acid, vanillin, and vanillyl alcohol. Bacterial isolates were evaluated using ferulic acid esterase, ferulic acid decarboxylase, and vanillin dehydrogenase assays. This work highlights the importance of lactic acid bacteria in phenolic biotransformations for the development of food grade flavours and additives.

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

    Science.gov (United States)

    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.

  16. Fermentative production of L: -(+)-lactic acid by an alkaliphilic marine microorganism.

    Science.gov (United States)

    Calabia, Buenaventurada P; Tokiwa, Yutaka; Aiba, Seiichi

    2011-07-01

    Of six strains of lactic acid-producing alkaliphilic microorganisms, Halolactibacillus halophilus was most efficient. It produced the highest concentration and yield of lactic acid, with minimal amounts of acetic and formic acid when sucrose and glucose were used as substrate. Mannose and xylose were poorly utilized. In batch fermentation at 30°C, pH 9 with 4 and 8% (w/v) sucrose, lactic acid was produced at 37.7 and 65.8 g l(-1), with yields of 95 and 83%, respectively. Likewise, when 4 and 8% (w/v) glucose were used, 33.4 and 59.6 g lactic acid l(-1) were produced with 85 and 76% yields, respectively. L: -(+)-lactic acid had an optical purity of 98.8% (from sucrose) and 98.3% (from glucose).

  17. Probiotic properties of endemic strains of lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Flora N. Tkhruni

    2013-01-01

    Full Text Available Strains of lactic acid bacteria (LAB isolated from various samples of matsun, yogurt and salted cheese from natural farms of Armenia were studied. They have high antimicrobial and probiotic activities, growth rate and differ by their resistance to enzymes. Supernatants of LAB retain bactericidal activity at рН 3.0-8.0 and inhibit growth of various microflora. The application of different methods of identification and LAB genotyping (API 50 CH, 16S rRNA sequencing, GS-PCR, RAPD PCR showed that isolated LAB evidenced a 99.9% similarity with L. rhamnosus, L. plantarum and L. pentosus species and coccoid forms of Streptococcus and Enterococcus species. It can be concluded, that some strains of lactic acid bacteria, isolated from dairy products from natural farms of Armenia, can be properly used for biopreservation of some foodstuffs. On the basis of experimental data, the LAB can be used as basis for obtaining the new products of functional nutrition.

  18. Potential of lactic acid bacteria in aflatoxin risk mitigation.

    Science.gov (United States)

    Ahlberg, Sara H; Joutsjoki, Vesa; Korhonen, Hannu J

    2015-08-17

    Aflatoxins (AF) are ubiquitous mycotoxins contaminating food and feed. Consumption of contaminated food and feed can cause a severe health risk to humans and animals. A novel biological method could reduce the health risks of aflatoxins through inhibiting mold growth and binding aflatoxins. Lactic acid bacteria (LAB) are commonly used in fermented food production. LAB are known to inhibit mold growth and, to some extent, to bind aflatoxins in different matrices. Reduced mold growth and aflatoxin production may be caused by competition for nutrients between bacterial cells and fungi. Most likely, binding of aflatoxins depends on environmental conditions and is strain-specific. Killed bacteria cells possess consistently better binding abilities for aflatoxin B1 (AFB1) than viable cells. Lactobacilli especially are relatively well studied and provide noticeable possibilities in binding of aflatoxin B1 and M1 in food. It seems that binding is reversible and that bound aflatoxins are released later on (Haskard et al., 2001; Peltonen et al., 2001). This literature review suggests that novel biological methods, such as lactic acid bacteria, show potential in mitigating toxic effects of aflatoxins in food and feed. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Probiotic lactic acid bacteria for applications in vegetarian food products

    Directory of Open Access Journals (Sweden)

    Charernjiratrakul, W.

    2007-07-01

    Full Text Available Total of 225 isolates of lactic acid bacteria were isolated from 152 samples of various fermented foods. The strains were investigated for their probiotic properties based on stability in bile salt (0.30% and high acidity (pH 3, growth under both aerobic and anaerobic conditions, ability to grow without vitamin B12. According to the above criteria, 40 isolates were selected. Using an agar spot method, 16 isolates were able to inhibit Salmonella typhimurium, S. typhi, S. enteritidis, S. paratyphi and 4 strains of E. coli O157 : H7 as clear zone greater than 10 mm. Moreover, utilization of protein or fat or starch was also considered. Only 5 isolates were able to utilize protein and further selected for antibiotics sensitivity test. The selected isolates were susceptible to following antibiotics: ampicillin, chloramphenicol, erythromycin , kanamycin, tetracycline and vancomycin; however they were resistant to ceptazidime and norfloxacin. They all showed better growth in vegetarian medium (coconut juice medium than MRS medium both under static and shaking conditions. Five active isolates were identified as Lactobacillus plantarum LL13, LN18, LP11, LS35 and Pediococcus pentosaceus LT02 by API 50 CH system. All cultures grew well in carrot juice by reducing pH from 6.4 to below 4.0 after 24 h of fermentation at 35oC. The lactic cultures in fermented carrot juice lost their viability about 2 log cycles after 15 days of cold storage at 4oC.

  20. The use of lactic acid bacteria to reduce mercury bioaccessibility.

    Science.gov (United States)

    Jadán-Piedra, C; Alcántara, C; Monedero, V; Zúñiga, M; Vélez, D; Devesa, V

    2017-08-01

    Mercury in food is present in either inorganic [Hg(II)] or methylmercury (CH3Hg) form. Intestinal absorption of mercury is influenced by interactions with other food components. The use of dietary components to reduce mercury bioavailability has been previously proposed. The aim of this work is to explore the use of lactic acid bacteria to reduce the amount of mercury solubilized after gastrointestinal digestion and available for absorption (bioaccessibility). Ten strains were tested by addition to aqueous solutions containing Hg(II) or CH3Hg, or to food samples, and submission of the mixtures to gastrointestinal digestion. All of the strains assayed reduce the soluble fraction from standards of mercury species under gastrointestinal digestion conditions (72-98%). However their effectiveness is lower in food, and reductions in bioaccessibility are only observed with mushrooms (⩽68%). It is hypothesized that bioaccessible mercury in seafood forms part of complexes that do not interact with lactic acid bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage

    Science.gov (United States)

    Wu, Jing-jing; Du, Rui-ping; Gao, Min; Sui, Yao-qiang; Xiu, Lei; Wang, Xiao

    2014-01-01

    Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage. PMID:25049999

  2. Identification of lactic acid bacteria isolated from corn stovers.

    Science.gov (United States)

    Pang, Huili; Zhang, Meng; Qin, Guangyong; Tan, Zhongfang; Li, Zongwei; Wang, Yanping; Cai, Yimin

    2011-10-01

    One hundred and twenty-six strains were isolated from corn stover in Henan Province, China, of which 105 isolates were considered to be lactic acid bacteria (LAB) according to Gram-positive, catalase-negative and mainly metabolic lactic acid product. Analysis of the 16S ribosomal DNA sequence of 21 representative strains was used to confirm the presence of the predominant groups and to determine the phylogenetic affiliation of isolates. The sequences from the various LAB isolates showed high degrees of similarity to those of the GenBank type strains between 99.4% and 100%. The prevalent LAB, predominantly Lactobacillus (85.6%), consisted of L. plantarum (33.3%), L. pentosus (28.6%) and L. brevis (23.7%). Other LAB species as Leuconostoc lactis (4.8%), Weissella cibaria (4.8%) and Enterococcus mundtii (4.8%) also presented in corn stover. The present study is the first to fully document corn stover-associated LAB involved in the silage fermentation. The identification results revealed LAB composition inhabiting corn stover and enabling the future design of appropriate inoculants aimed at improving the fermentation quality of silage. © 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.

  3. Monitoring lactic acid production during milk fermentation by in situ quantitative proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Bouteille, R; Gaudet, M; Lecanu, B; This, H

    2013-04-01

    When fermenting milk, lactic bacteria convert part of α- and β-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the α- and β-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism.

  4. 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 repor

  5. 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 repor

  6. 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

  7. Key volatile aroma compounds of lactic acid fermented malt based beverages - impact of lactic acid bacteria strains.

    Science.gov (United States)

    Nsogning Dongmo, Sorelle; Sacher, Bertram; Kollmannsberger, Hubert; Becker, Thomas

    2017-08-15

    This study aims to define the aroma composition and key aroma compounds of barley malt wort beverages produced from fermentation using six lactic acid bacteria (LAB) strains. Gas chromatography mass spectrometry-olfactometry and flame ionization detection was employed; key aroma compounds were determined by means of aroma extract dilution analysis. Fifty-six detected volatile compounds were similar among beverages. However, significant differences were observed in the concentration of individual compounds. Key aroma compounds (flavor dilution (FD) factors ≥16) were β-damascenone, furaneol, phenylacetic acid, 2-phenylethanol, 4-vinylguaiacol, sotolon, methional, vanillin, acetic acid, nor-furaneol, guaiacol and ethyl 2-methylbutanoate. Furthermore, acetaldehyde had the greatest odor activity value of up to 4266. Sensory analyses revealed large differences in the flavor profile. Beverage from L. plantarum Lp. 758 showed the highest FD factors in key aroma compounds and was correlated to fruity flavors. Therefore, we suggest that suitable LAB strain selection may improve the flavor of malt based beverages.

  8. Synthesis and characterization of poly(lactic acid-co-glycolic acid) complex microspheres as drug carriers.

    Science.gov (United States)

    Wang, Fang; Liu, Xiuxiu; Yuan, Jian; Yang, Siqian; Li, Yueqin; Gao, Qinwei

    2016-10-01

    Poly(lactic-co-glycolic) acid (PLGA) is synthesized via melt polycondensation directly from lactic acid and glycolic acid with a feed molar ratio of 75/25. Bovine serum albumin, which is used as model protein, is entrapped into the poly(lactic-co-glycolic acid) microspheres with particle size of 260.9 ± 20.0 nm by the double emulsification method. Then it is the first report of producing more carboxyl groups by poly(lactic-co-glycolic acid) surface hydrolysis. The purpose is developing poly(lactic-co-glycolic acid) microspheres surface, which is modified with chitosan by chemical reaction between carboxyl groups and amine groups. The particle size and the positive zeta potential of the poly(lactic-co-glycolic acid)/chitosan microspheres are 388.2 ± 35.6 nm and 10.4 ± 2.9 mV, respectively. The drug loading ratio and encapsulation efficacy of poly(lactic-co-glycolic acid)/chitosan microspheres are 36.3% and 57.5%, which are higher than PLGA microspheres. Furthermore, the drug burst release of poly(lactic-co-glycolic acid)/chitosan microspheres at 10 h is decreased to 21.72% while the corresponding value of the poly(lactic-co-glycolic acid) microsphere is 64.56%. These results reveal that surface hydrolysis modification of poly(lactic-co-glycolic acid) is an efficient method to improve the negative potential and chemical reaction properties of the polymer. And furthermore, this study shows that chitosan-modified poly(lactic-co-glycolic acid) microspheres is a promising system for the controlled release of pharmaceutical proteins.

  9. Antifungal Activity of Selected Lactic Acid Bacteria and Propionic Acid Bacteria against Dairy-Associated Spoilage Fungi

    DEFF Research Database (Denmark)

    Aunsbjerg, Stina Dissing

    Bacterial cultures of lactic and propionic acid bacteria are widely used in fermented products including dairy products. Spoilage fungi may constitute a quality and safety issue in these products. The antifungal properties of some lactic and propionic acid bacteria make them potential candidates...... diacetyl and lactic acid, 6 antifungal hydroxy acids were identified. Of these, 3 have previously been reported from antifungal lactic acid bacteria, whereas the other 3 hydroxy acids have not previously been reported produced by antifungal lactic acid bacteria....... factors thereby facilitating development of new protective cultures. The aim of the current thesis was to determine and study metabolites involved in antifungal activity of protective Lactobacillus paracasei and Propionibacterium freudenreichii subsp. shermanii. This involved development of a suitable...

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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.

  12. In situ separation of lactic acid from fermentation broth using ion exchange resins.

    Science.gov (United States)

    Ataei, Seyed Ahmad; Vasheghani-Farahani, Ebrahim

    2008-11-01

    Lactic acid fermentation is an end product inhibited reaction. In situ separation of lactic acid from fermentation broth using ion exchange resins was investigated and compared with conventional fermentation system. Amberlite resin (IRA-400, Cl-) was used to separate lactic acid from fermentation broth and pH was controlled online with an automatic pH controller. The effect of process variables on lactic acid production by Lactobacillus casei in whey permeate was studied. The maximum productivity was obtained at pH=6.1, T=37 degrees C and impeller speed=200 rpm. The maximum concentration of lactic acid at optimum condition was found to be 37.4 g/L after 38 h of fermentation using in situ separation system. The productivity of in situ separation system was five times increased in comparison with conventional system.

  13. [Analysis of microbial community structure in lactic acid fermentation from kitchen waste].

    Science.gov (United States)

    Liu, Jian-Guo; Wang, Qun-Hui; Wang, Shuang; Sun, Xiao-Hong; Qiu, Tian-Lei; Li, Huan

    2012-09-01

    In this study, PCR-DGGE was used to analyze the microbial community structure in lactic acid fermentation from kitchen waste. The results showed that with Lactobacillus amylophilus inoculation, both the microbial diversity and lactic acid production in the open fermentation system were higher than those in the sterilized fermentation system. These results indicated that the microbial diversity and the lactic acid production have great correlation in the kitchen waste fermentation system. Through analyzing the sequence of some DNA bands excised from the DGGE gel, it showed that in addition to the inoculation of Lactobacillus amylophilus there were some indigenous lactic acid bacteria, such as Lactobacillus sp., Lactobacillus casei, Lactobacillus plantarum and indigenous hydrolytic bacteria, such as Pseudomonas sp.. These indigenous bacteria can help to promote lactic acid production. PCR-DGGE is feasible for analyzing the dynamic changes of microbial community structure in kitchen waste with complicated composition.

  14. Semicontinuous Production of Lactic Acid From Cheese Whey Using Integrated Membrane Reactor

    Science.gov (United States)

    Li, Yebo; Shahbazi, Abolghasem; Coulibaly, Sekou; Mims, Michele M.

    Semicontinuous production of lactic acid from cheese whey using free cells of Bifidobacterium longum with and without nanofiltration was studied. For the semicontinuous fermentation without membrane separation, the lactic acid productivity of the second and third runs is much lower than the first run. The semicontinuous fermentation with nanoseparation was run semicontinuously for 72 h with lactic acid to be harvested every 24 h using a nanofiltration membrane unit. The cells and unutilized lactose were kept in the reactor and mixed with newly added cheese whey in the subsequent runs. Slight increase in the lactic acid productivity was observed in the second and third runs during the semicontinuous fermentation with nanofiltration. It can be concluded that nanoseparation could improve the lactic acid productivity of the semicontinuous fermentation process.

  15. 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

    -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......Corncob is an economic feedstock and more than 20 million tons of corncobs are produced annually in China. Abundant xylose can be potentially converted from the large amount of hemicellulosic materials in corncobs, which makes the crop residue an attractive alternative substrate for a value......-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...

  16. Hydrolytic breakdown of lactoferricin by lactic acid bacteria.

    Science.gov (United States)

    Paul, Moushumi; Somkuti, George A

    2010-02-01

    Lactoferricin is a 25-amino acid antimicrobial peptide fragment that is liberated by pepsin digestion of lactoferrin present in bovine milk. Along with its antibacterial properties, lactoferricin has also been reported to have immunostimulatory, antiviral, and anticarcinogenic effects. These attributes provide lactoferricin and other natural bioactive peptides with the potential to be functional food ingredients that can be used by the food industry in a variety of applications. At present, commercial uses of these types of compounds are limited by the scarcity of information on their ability to survive food processing environments. We have monitored the degradation of lactoferricin during its incubation with two types of lactic acid bacteria used in the yogurt-making industry, Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, with the aim of assessing the stability of this milk protein-derived peptide under simulated yogurt-making conditions. Analysis of the hydrolysis products isolated from these experiments indicates degradation of this peptide near neutral pH by lactic acid bacteria-associated peptidases, the extent of which was influenced by the bacterial strain used. However, the data also showed that compared to other milk-derived bioactive peptides that undergo complete degradation under these conditions, the 25-amino acid lactoferricin is apparently more resistant, with approximately 50% of the starting material remaining after 4 h of incubation. These findings imply that lactoferricin, as a natural milk protein-derived peptide, has potential applications in the commercial production of yogurt-like fermented dairy products as a multi-functional food ingredient.

  17. Bacteriocins produced by lactic acid bacteria: A review

    Directory of Open Access Journals (Sweden)

    Vesković-Moračanin Slavica M.

    2014-01-01

    Full Text Available Lactic acid bacteria (LAB have an essential role in the production of fermented products. With their metabolic activity, they influence the ripening processes - leading to desired sensory qualities while at the same time inhibiting the growth of undesired microorganisms. Because of their dominant role during fermentation and because of a long tradition of utilization, Lhave been designated as “safe microbiota”. Biological protection of LAB, as a naturally present and/or selected and intentionally added microflora, is realized through the production of non-specific (lactic acid, acetic acid and other volatile organic acids, hydrogen peroxide, diacetyl, etc and specific metabolites, bacteriocins. Bacteriocins are extracellularly released proteins or peptides which possess certain antibacterial activity towards certain types of microorganisms, usually related to the producing bacteria. Today, bacteriocins represent a very interesting potential for their application in the food industry. Their application can reduce the use of synthetic preservatives and/or the intensity of thermal treatment during food production consumer’s need for safe, fresh and minimally-processed food. With the intention of realizing this potential to the fullest, it is necessary to understand the nature of bacteriocins, their production mechanisms, regulations and actions, as well as the influence of external factors on the their antimicrobial activity. The composition of food, i.e. its characteristics (pH, temperature, ingredients and additives, types and quantities of epiphytic microbiota and the actual technological process used in production, can all influence the stability and activity of the added bacteriocins. The future research in this field should also aim to clarify this unknown aspect of the application of bacteriocins, to provide the necessary knowledge about the optimization of the external conditions and open up the possibility of discovering their new

  18. 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...

  19. Metabolic strategies of beer spoilage lactic acid bacteria in beer.

    Science.gov (United States)

    Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

    2016-01-04

    Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis.

  20. Fermentation of aqueous plant seed extracts by lactic acid bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Schafner, D.W.; Beuchat, R.L.

    1986-05-01

    The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. PREPARATION AND PROPERTIES OF POLY (LACTIC ACID-CO-GLYCOL TEREPHTHALIC ACID) COPOLYESTER

    Institute of Scientific and Technical Information of China (English)

    GAO Cuili; JI Quan; KONG Qingshan; XIA Yanzhi

    2006-01-01

    To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly(lactic acid-co-glycol terephthalate) (PETA), was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, 1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the TmS and TdS of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.

  3. Safety evaluation of poly(lactic-co-glycolic acid/poly(lactic-acid microspheres through intravitreal injection in rabbits

    Directory of Open Access Journals (Sweden)

    Rong XF

    2014-06-01

    Full Text Available Xianfang Rong,1 Weien Yuan,2 Yi Lu,1 Xiaofen Mo11Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, People’s Republic of China; 2School of Pharmacy, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaAbstract: Poly(lactic-co-glycolic acid (PLGA and/or poly(lactic-acid (PLA microspheres are important drug delivery systems. This study investigated eye biocompatibility and safety of PLGA/PLA microspheres through intravitreal injection in rabbits. Normal New Zealand rabbits were randomly selected and received intravitreal administration of different doses (low, medium, or high of PLGA/PLA microspheres and erythropoietin-loaded PLGA/PLA microspheres. The animals were clinically examined and sacrificed at 1, 2, 4, 8, and 12 weeks postadministration, and retinal tissues were prepared for analysis. Retinal reactions to the microspheres were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end staining and glial fibrillary acidic protein immunohistochemistry. Retinal structure changes were assessed by hematoxylin and eosin staining and transmission electron microscopy. Finally, retinal function influences were explored by the electroretinography test. Terminal deoxynucleotidyl transferase-mediated dUTP nick end staining revealed no apoptotic cells in the injected retinas; immunohistochemistry did not detect any increased glial fibrillary acidic protein expression. Hematoxylin and eosin staining and transmission electron microscopy revealed no micro- or ultrastructure changes in the retinas at different time points postintravitreal injection. The electroretinography test showed no significant influence of scotopic or photopic amplitudes. The results demonstrated that PLGA/PLA microspheres did not cause retinal histological changes or functional damage and were biocompatible and safe enough for intravitreal injection in rabbits for controlled

  4. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri

    NARCIS (Netherlands)

    Elferink, SJWHO; Krooneman, J; Gottschal, JC; Spoelstra, SF; Faber, F; Driehuis, F

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lac

  5. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri

    NARCIS (Netherlands)

    Elferink, SJWHO; Krooneman, J; Gottschal, JC; Spoelstra, SF; Faber, F; Driehuis, F

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade

  6. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S.F.; Faber, F.; Driehuis, F.

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade

  7. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediol by Lactobacillus buchneri

    NARCIS (Netherlands)

    Elferink, S.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S.F.; Faber, F.; Driehuis, F.

    2001-01-01

    The degradation of lactic acid under anoxic conditions was studied in several strains of Lactobacillus buchneri and in close relatives such as Lactobacillus parabuchneri, Lactobacillus kefir, and Lactobacillus hilgardii. Of these lactobacilli, L. buchneri and L. parabuchneri were able to degrade lac

  8. Engineering cellular redox balance in Saccharomyces cerevisiae for improved production of L-lactic acid.

    Science.gov (United States)

    Lee, Ju Young; Kang, Chang Duk; Lee, Seung Hyun; Park, Young Kyoung; Cho, Kwang Myung

    2015-04-01

    Owing to the growing market for the biodegradable and renewable polymer, polylactic acid, world demand for lactic acid is rapidly increasing. However, the very high concentrations desired for industrial production of the free lactic acid create toxicity and low pH concerns for manufacturers. Saccharomyces cerevisiae is the most well characterized eukaryote, a preferred microbial cell factory for the largest industrial biotechnology product (bioethanol), and a robust, commercially compatible workhorse to be exploited for the production of diverse chemicals. S. cerevisiae has also been explored as a host for lactic acid production because of its high acid tolerance. Here, we constructed an L-lactic acid-overproducing S. cerevisiae by redirecting cellular metabolic fluxes to the production of L-lactic acid. To this end, we deleted the S. cerevisiae genes encoding pyruvate decarboxylase 1 (PDC1), L-lactate cytochrome-c oxidoreductase (CYB2), and glycerol-3-phosphate dehydrogenase (GPD1), replacing them with a heterologous L-lactate dehydrogenase (LDH) gene. Two new target genes encoding isoenzymes of the external NADH dehydrogenase (NDE1 and NDE2), were also deleted from the genome to re-engineer the intracellular redox balance. The resulting strain was found to produce L-lactic acid more efficiently (32.6% increase in final L-lactic acid titer). When tested in a bioreactor in fed-batch mode, this engineered strain produced 117 g/L of L-lactic acid under low pH conditions. This result demonstrates that the redox balance engineering should be coupled with the metabolic engineering in the construction of L-lactic acid-overproducing S. cerevisiae.

  9. Influence of lactic acid on the two-phase anaerobic digestion of kitchen wastes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; CAI Wei-min; HE Pin-jing

    2007-01-01

    To evaluate the influence of lactic acid on the methanogenesis, anaerobic digestion of kitchen wastes was firstly conducted in a two-phase anaerobic digestion process, and performance of two digesters fed with lactic acid and glucose was subsequently compared.The results showed that the lactic acid was the main fermentation products of hydrolysis-acidification stage in the two-phase anaerobic digestion process for kitchen wastes. The lactic acid concentration constituted approximately 50% of the chemical oxygen demand (COD) concentration in the hydrolysis-acidification liquid. The maximum organic loading rate was lower in the digester fed with lactic acid than that fed with glucose. Volatile fatty acids (VFAs) and COD removal were deteriorated in the methanogenic reactor fed with to the high concentration of lactic acid fed. It could be concluded that avoiding the presence of the lactic acid is necessary in the hydrolysis-acidification process for the improvement of the two-phase anaerobic digestion process of kitchen wastes.

  10. NANOCOMPOSITES OF POLY(LACTIC ACID REINFORCED WITH CELLULOSE NANOFIBRILS

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    2010-06-01

    Full Text Available A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol (PEG 1000 was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid (PLA and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc were characterized by tensile testing machine, atomic force microscope (AFM, scanning electron microscope (SEM, and Fourier transform infrared spectroscopy (FT-IR. The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils.

  11. Antibiotic susceptibility of different lactic acid bacteria strains.

    Science.gov (United States)

    Karapetkov, N; Georgieva, R; Rumyan, N; Karaivanova, E

    2011-12-01

    Five lactic acid bacteria (LAB) strains belonging to species Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus delbrueckii subsp. lactis and Streptococcus thermophilus were tested for their susceptibility to 27 antibiotics. The minimum inhibitory concentrations of each antimicrobial were determined using a microdilution test. Among the strains a high susceptibility was detected for most of the cell-wall synthesis inhibitors (penicillins, cefoxitin and vancomycin) and resistance toward inhibitors of DNA synthesis (trimethoprim/sulfonamides and fluoroquinolones). Generally, the Lactobacillus strains were inhibited by antibiotics such as chloramphenicol, erythromycin and tetracycline at breakpoint levels lower or equal to the levels defined by the European Food Safety Authority. Despite the very similar profile of S. thermophilus LC201 to lactobacilli, the detection of resistance toward erythromycin necessitates the performance of additional tests in order to prove the absence of transferable resistance genes.

  12. Development of Mucosal Vaccines Based on Lactic Acid Bacteria

    Science.gov (United States)

    Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

    Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

  13. Modelling strategies for the industrial exploitation of lactic acid bacteria.

    Science.gov (United States)

    Teusink, Bas; Smid, Eddy J

    2006-01-01

    Lactic acid bacteria (LAB) have a long tradition of use in the food industry, and the number and diversity of their applications has increased considerably over the years. Traditionally, process optimization for these applications involved both strain selection and trial and error. More recently, metabolic engineering has emerged as a discipline that focuses on the rational improvement of industrially useful strains. In the post-genomic era, metabolic engineering increasingly benefits from systems biology, an approach that combines mathematical modelling techniques with functional-genomics data to build models for biological interpretation and--ultimately--prediction. In this review, the industrial applications of LAB are mapped onto available global, genome-scale metabolic modelling techniques to evaluate the extent to which functional genomics and systems biology can live up to their industrial promise.

  14. Thermogravimetric and DSC testing of poly(lactic acid) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Mróz, Patrycja; Białas, Sylwia [Faculty of Process and Environmental Engineering, Technical University of Łódź, Wólczańska 15 Street, 90-924 Łódź (Poland); Mucha, Maria, E-mail: muchama@wipos.p.lodz.pl [Faculty of Process and Environmental Engineering, Technical University of Łódź, Wólczańska 15 Street, 90-924 Łódź (Poland); Kaczmarek, Halina [Nicolaus Copernicus University, Faculty of Chemistry, Gagarin 7 Street, 87-100 Toruń (Poland)

    2013-12-10

    Highlights: • The presence of nanoadditivities in PLA matrix improves thermal stability of PLA. • Shielding effect main reason for PLA thermal stability by nanofillers. • Thermal degradation suppression in UV-irradiated PLA by the removing of unstable compounds. - Abstract: Polymer nanocomposites based on poly(lactic acid), PLA, and two types of nanofillers: nanosilver and nanoclay were obtained by casting method. The thermal properties of PLA and nanocomposites have been studied by thermogravimetric analysis (TA) and differential scanning calorimetry (DSC). All samples have been UV-irradiated and the effect of photoprocess on their thermal stability has been estimated. It was found that nanoadditives and UV irradiation causes an increase of the activation energy of PLA thermal decomposition. DSC result supplies information on glass transition and crystallization/melting processes in PLA in the presence of nanosilver or nanoclay, also after exposure to UV.

  15. Application of poly(lactic acid) modified by radiation crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Naotsugu [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)]. E-mail: nao@taka.jaeri.go.jp; Kaneda, Ayako [Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Kanazawa, Shinichi [Sumitomo Electric Fine Polymer, Inc., 1-950 Asashironishi, Kumatori-cho, Sennan-gun, Osaka 590-0458 (Japan); Yagi, Toshiaki [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Mitomo, Hiroshi [Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515 (Japan); Yoshii, Fumio [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Tamada, Masao [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan)

    2005-07-01

    Poly(L-lactic acid), PLLA was irradiated using electron beam (EB) in the presence of polyfunctional monomers (PFM) as crosslinking agent. Among the PFMs, triallyl isocyanurate (TAIC) at 3% concentration was found to be the most effective for crosslinking of PLLA by irradiation technique. The crosslinked PLLA obtained has heat resistance higher than 200 deg. C. From this fact, the crosslinked PLLA is applied on heat-shrinkable tube, cup and plate. The shrinkable tube has several advantages such as high heat resistance and transparency. In addition, the unirradiated cup deformed and changed to milky-like transparency but the crosslinked one retained its original shape and transparency after boiling water was poured into the cups. The heat resistance is attributed to the protection of crystallization of crosslinking structure. It is therefore proven that crosslinking technology is beneficial to expanding the application of PLLA.

  16. Application of poly(lactic acid) modified by radiation crosslinking

    Science.gov (United States)

    Nagasawa, Naotsugu; Kaneda, Ayako; Kanazawa, Shinichi; Yagi, Toshiaki; Mitomo, Hiroshi; Yoshii, Fumio; Tamada, Masao

    2005-07-01

    Poly(L-lactic acid), PLLA was irradiated using electron beam (EB) in the presence of polyfunctional monomers (PFM) as crosslinking agent. Among the PFMs, triallyl isocyanurate (TAIC) at 3% concentration was found to be the most effective for crosslinking of PLLA by irradiation technique. The crosslinked PLLA obtained has heat resistance higher than 200 °C. From this fact, the crosslinked PLLA is applied on heat-shrinkable tube, cup and plate. The shrinkable tube has several advantages such as high heat resistance and transparency. In addition, the unirradiated cup deformed and changed to milky-like transparency but the crosslinked one retained its original shape and transparency after boiling water was poured into the cups. The heat resistance is attributed to the protection of crystallization of crosslinking structure. It is therefore proven that crosslinking technology is beneficial to expanding the application of PLLA.

  17. Frustrated smectic liquid crystalline phases in lactic acid derivatives

    Science.gov (United States)

    Glogarová, M.; Novotná, V.

    2016-08-01

    We have prepared and studied a series of compounds with different types of molecular core and lactate unit in the chiral terminal chain. We draw a survey and comparison of their mesomorphic properties with respect to the occurrence of twist grain boundary (TGB) phases. The materials exhibit extremely wide TGBA phase more than 60K broad, unique TGBA-TGBC-SmC*-SmCA* phase sequence and unique re-entrant TGBA phase below the SmA phase. TGB phases have been induced in binary mixtures of molecules with different molecular shape and chirality (chiral lactic acid derivative and non-chiral hockey-stick mesogen). Unique effect is observed for compounds with TGBA phase, where the applied electric field transforms the planar texture into the homeotropic one, homogeneously dark in crossed polarizers. The process is analogy of the Frederiks transition so far known only for nematics. This effect, changing the bright state to the dark one, is promising for applications.

  18. Formability Analysis of Bamboo Fabric Reinforced Poly (Lactic Acid Composites

    Directory of Open Access Journals (Sweden)

    Nurul Fazita M. R.

    2016-07-01

    Full Text Available Poly (lactic acid (PLA composites have made their way into various applications that may require thermoforming to produce 3D shapes. Wrinkles are common in many forming processes and identification of the forming parameters to prevent them in the useful part of the mechanical component is a key consideration. Better prediction of such defects helps to significantly reduce the time required for a tooling design process. The purpose of the experiment discussed here is to investigate the effects of different test parameters on the occurrence of deformations during sheet forming of double curvature shapes with bamboo fabric reinforced-PLA composites. The results demonstrated that the domes formed using hot tooling conditions were better in quality than those formed using cold tooling conditions. Wrinkles were more profound in the warp direction of the composite domes compared to the weft direction. Grid Strain Analysis (GSA identifies the regions of severe deformation and provides useful information regarding the optimisation of processing parameters.

  19. Screening and characterization of novel bacteriocins from lactic acid bacteria.

    Science.gov (United States)

    Zendo, Takeshi

    2013-01-01

    Bacteriocins produced by lactic acid bacteria (LAB) are expected to be safe antimicrobial agents. While the best studied LAB bacteriocin, nisin A, is widely utilized as a food preservative, various novel ones are required to control undesirable bacteria more effectively. To discover novel bacteriocins at the early step of the screening process, we developed a rapid screening system that evaluates bacteriocins produced by newly isolated LAB based on their antibacterial spectra and molecular masses. By means of this system, various novel bacteriocins were identified, including a nisin variant, nisin Q, a two-peptide bacteriocin, lactococcin Q, a leaderless bacteriocin, lacticin Q, and a circular bacteriocin, lactocyclicin Q. Moreover, some LAB isolates were found to produce multiple bacteriocins. They were characterized as to their structures, mechanisms of action, and biosynthetic mechanisms. Novel LAB bacteriocins and their biosynthetic mechanisms are expected for applications such as food preservation and peptide engineering.

  20. Antiviral potential of lactic acid bacteria and their bacteriocins.

    Science.gov (United States)

    Al Kassaa, I; Hober, D; Hamze, M; Chihib, N E; Drider, D

    2014-12-01

    Emerging resistance to antiviral agents is a growing public health concern worldwide as it was reported for respiratory, sexually transmitted and enteric viruses. Therefore, there is a growing demand for new, unconventional antiviral agents which may serve as an alternative to the currently used drugs. Meanwhile, published literature continues shedding the light on the potency of lactic acid bacteria (LAB) and their bacteriocins as antiviral agents. Health-promoting LAB probiotics may exert their antiviral activity by (1) direct probiotic-virus interaction; (2) production of antiviral inhibitory metabolites; and/or (3) via stimulation of the immune system. The aim of this review was to highlight the antiviral activity of LAB and substances they produce with antiviral activity.

  1. Genomics of lactic acid bacteria: Current status and potential applications.

    Science.gov (United States)

    Wu, Chongde; Huang, Jun; Zhou, Rongqing

    2017-08-01

    Lactic acid bacteria (LAB) are widely used for the production of a variety of foods and feed raw materials where they contribute to flavor and texture of the fermented products. In addition, specific LAB strains are considered as probiotic due to their health-promoting effects in consumers. Recently, the genome sequencing of LAB is booming and the increased amount of published genomics data brings unprecedented opportunity for us to reveal the important traits of LAB. This review describes the recent progress on LAB genomics and special emphasis is placed on understanding the industry-related physiological features based on genomics analysis. Moreover, strategies to engineer metabolic capacity and stress tolerance of LAB with improved industrial performance are also discussed.

  2. Determination of peroxy radical-scavenging of lactic acid bacteria.

    Science.gov (United States)

    Stecchini, M L; Del Torre, M; Munari, M

    2001-02-28

    Responses of lactic acid bacteria (LAB) to peroxy radicals generated via thermal (40 degrees C) decomposition of the diazocompound 2,2,-azo-bis (2-amidinopropane) dihydrochloride (ABAP), were studied. In general, LAB displayed survival curves with shoulders and tails indicative of 'multihit' killing by exposure to peroxy radicals. One strain, Lactococcus lactis subsp. lactis DIP15, producing a slope of 0.0105 in the kinetic analysis when exposed to 4 mM ABAP, exhibited a measurable antioxidant capacity. The other LAB failed to show any significant antioxidant capacity. The antioxidant capacity of strain DIP15 remained constant after cells have been heat-treated, suggesting that compounds bearing free radical scavenging capacity are rather stable.

  3. Lactic acid bacteria as adjuvants for sublingual allergy vaccines.

    Science.gov (United States)

    Van Overtvelt, Laurence; Moussu, Helene; Horiot, Stéphane; Samson, Sandrine; Lombardi, Vincent; Mascarell, Laurent; van de Moer, Ariane; Bourdet-Sicard, Raphaëlle; Moingeon, Philippe

    2010-04-01

    We compared immunomodulatory properties of 11 strains of lactic acid bacteria as well as their capacity to enhance sublingual immunotherapy efficacy in a murine asthma model. Two types of bacterial strains were identified, including: (i) potent inducers of IL-12p70 and IL-10 in dendritic cells, supporting IFN-gamma and IL-10 production in CD4+ T cells such as Lactobacillus helveticus; (ii) pure Th1 inducers such as L. casei. Sublingual administration in ovalbumin-sensitized mice of L. helveticus, but not L. casei, reduced airways hyperresponsiveness, bronchial inflammation and proliferation of specific T cells in cervical lymph nodes. Thus, probiotics acting as a Th1/possibly Treg, but not Th1 adjuvant, potentiate tolerance induction via the sublingual route.

  4. Current taxonomy of phages infecting lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Jennifer eMahony

    2014-01-01

    Full Text Available Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp. and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species.

  5. Poly(lactic acid) for delivery of bioactive macromolecules.

    Science.gov (United States)

    James, Roshan; Manoukian, Ohan S; Kumbar, Sangamesh G

    2016-12-15

    Therapeutic biomolecules often require frequent administration and supramolecular dosing to achieve therapeutic efficiencies and direct infusion into treatment or defect sites results in inadequate physiological response and at times severe side effects or mis-targeting. Delivery systems serve several purposes such as increased circulatory time, increased biomolecule half-life, and incorporation of new innovations can enable highly specific cell targeting and improved cell and nucleus permeability. Poly(lactic acid) (PLA) has become a "material of choice" due to wide availability, reproducible synthetic route, customization, versatility, biodegradability and biocompatibility. Furthermore, PLA is amenable to a variety of fabrication methodologies and chemistries allowing an expansive library correlating physio-chemical properties, characteristics, and applications. This article discusses challenges to biomolecule delivery, and classical approaches of PLA based biomolecule delivery and targeting strategies under development and in trials.

  6. [Lactic acid bacteria and health: are probiotics safe for human?].

    Science.gov (United States)

    Kubiszewska, Izabela; Januszewska, Milena; Rybka, Joanna; Gackowska, Lidia

    2014-11-17

    The effect of Lactobacillus and Bifidobacterium on human health has been examined for many years. Numerous in vivo and in vitro studies have confirmed the beneficial activity of some exogenous lactic acid bacteria in the treatment and prevention of rotaviral infection, antibiotic-associated diarrhea, inflammatory bowel disease and other gastrointestinal disorders. Probiotics support the action of the intestinal microflora and exhibit a favorable modulatory effect on the host's immune system. However, it should be remembered that relatively harmless lactobacilli can occasionally induce opportunistic infections. Due to reaching almost 20x10(12) probiotic doses per year which contain live cultures of bacteria, it is essential to monitor the safety aspect of their administration. In recent years, infections caused by Lactobacillus and Bifidobacterium made up 0.05% to 0.4% of cases of endocarditis and bacteremia. In most cases, the infections were caused by endogenous microflora of the host or bacterial strains colonizing the host's oral cavity. According to a review of cases of infections caused by bacteria of the genus Lactobacillus from 2005 (collected by J.P. Cannot'a), 1.7% of infections have been linked directly with intensive dairy probiotic consumption by patients. Additionally, due to the lack of a precise description of most individuals' eating habits, the possible effect of probiotics on infection development definitively should not be ruled out. The present paper describes cases of diseases caused by lactic acid bacteria, a potential mechanism for the adverse action of bacteria, and the possible hazard connected with probiotic supplementation for seriously ill and hospitalized patients.

  7. 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.

  8. 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.

  9. 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

    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...... decreased in the same substrates. The final pH of the cereal lactic beverage was in the range of 3.4 - 4.1, L. mesenteroides(sikhae) had relatively higher pH compared to other lactic acid bacteria. L. mesenteroides(sikhae) produced apple juice-like flavor, while L. plantarum, L. casei and L. lactis yielded...... objectionable off-flavor. The HPLC analysis shoved that the lactic ferment of L. mesenteroides(sikhae) contained relatively small amount of lactic acid and malic acid which vas not detected in other microorganisms tested....

  10. Isolation and Identification of Epiphytic Lactic Acid Bacteria from Guinea Grass (Panicum maximum

    Directory of Open Access Journals (Sweden)

    M. Pasebani

    2010-01-01

    Full Text Available Problem statement: Bacteria can perform a variety of beneficial functions, for example many lactic acid bacteria are responsible for fermentation of silage in the process of forage conservation. In the making of silage, epiphytic lactic acid bacteria are usually insufficient in numbers to promote efficient lactate fermentation. This study was conducted to identify the predominant indigenous bacteria, with emphasis on lactic acid bacteria, from Guinea grass (Panicum maximum. Approach: Two different condition of growth using nutrient and MRS agar were prepared for isolation of the bacteria. In total, 18 purified isolates were identified by BIOLOG identification system which comprised of 9 bacterial species. Standard plate count in the both conditions was considered. Results: Three bacterial species based on the first condition of growth were identified which were belonging to Flavimonas oryzihabitans, Enerobacter cloacae, Sphingomonas paucimobilis B. Lactic acid bacteria based on the second condition of growth were belonging to Weissella confusa, Weissella paramesenteroides, Leuconostoc mesenteroides ssp. dextranicum, Lactococcus lactis ssp. hordniae. Result of plate count showed that 8.3×103 CFU lactic acid bacteria are available per gram of fresh guinea grass. Conclusion: Three hetero-fermentative and one homo-fermentative lactic acid bacteria were identified which would be suggested to use as bacterial inoculants because of the insufficient amount of epiphytic lactic acid bacteria and the availability of pathogenic bacteria in the grass.

  11. Who will win the race in childrens' oral cavities? Streptococcus mutans or beneficial lactic acid bacteria?

    Science.gov (United States)

    Güngör, Ö E; Kırzıoğlu, Z; Dinçer, E; Kıvanç, M

    2013-09-01

    Adhesion to oral soft and hard tissue is crucial for bacterial colonisation in the mouth. The aim of this work was to select strains of oral lactic acid bacteria that could be used as probiotics for oral health. To this end, the adhesive properties of some lactic acid bacteria were investigated. Seventeen lactic acid bacteria including two Streptococcus mutans strains were isolated from the oral cavity of healthy children, while other strains were isolated from fermented meat products. The bacterial strains were applied to teeth surfaces covered with saliva or without saliva. A significant diversity in adhesion capacity to teeth surfaces among the lactic acid bacteria was observed. Lactic acid bacteria isolated from the oral cavity adhered the best to teeth surfaces covered with saliva, whereas lactic acid bacteria isolated from fermented meat samples adhered the best to tooth surface without saliva. All strains of lactic acid bacteria were able to reduce the number of S. mutans cells, in particular on saliva-coated tooth surface. Therefore, they might have potential as probiotics for the oral cavity.

  12. Poly(lactic-co-glycolic acid) conduit for repair of injured sciatic nerve A mechanical analysis*

    Institute of Scientific and Technical Information of China (English)

    Tao Yu; Changfu Zhao; Peng Li; Guangyao Liu; Min Luo

    2013-01-01

    Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic nerve injury. This study col ected the sciatic nerve from the gluteus maximus muscle from fresh human cadaver, and established 10-mm-long sciatic nerve injury models by removing the ischium, fol owing which poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts were transplanted. Scanning electron microscopy revealed that the axon and myelin sheath were torn, and the vessels of basilar membrane were obstructed in the poly(lactic-co-glycolic acid) con-duit-repaired sciatic nerve fol owing tensile testing. There were no significant differences in tensile tests with autogenous nerve graft-repaired sciatic nerve. Fol owing poly(lactic-co-glycolic acid) conduit transplantation for sciatic nerve repair, tensile test results suggest that maximum tensile load, maximum stress, elastic limit load and elastic limit stress increased compared with autogen-ous nerve grafts, but elastic limit strain and maximum strain decreased. Moreover, the tendencies of stress-strain curves of sciatic nerves were similar after transplantation of poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts. Results showed that after transplantation in vitro for sciatic nerve injury, poly(lactic-co-glycolic acid) conduits exhibited good intensity, elasticity and plasticity, indicating that poly(lactic-co-glycolic acid) conduits are suitable for sciatic nerve injury repair.

  13. 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.

  14. Separate and Concentrate Lactic Acid Using Combination of Nanofiltration and Reverse Osmosis Membranes

    Science.gov (United States)

    Li, Yebo; Shahbazi, Abolghasem; Williams, Karen; Wan, Caixia

    The processes of lactic acid production include two key stages, which are (a) fermentation and (b) product recovery. In this study, free cell of Bifidobacterium longum was used to produce lactic acid from cheese whey. The produced lactic acid was then separated and purified from the fermentation broth using combination of nanofiltration and reverse osmosis membranes. Nanofiltration membrane with a molecular weight cutoff of 100-400 Da was used to separate lactic acid from lactose and cells in the cheese whey fermentation broth in the first step. The obtained permeate from the above nanofiltration is mainly composed of lactic acid and water, which was then concentrated with a reverse osmosis membrane in the second step. Among the tested nanofiltration membranes, HL membrane from GE Osmonics has the highest lactose retention (97±1%). In the reverse osmosis process, the ADF membrane could retain 100% of lactic acid to obtain permeate with water only. The effect of membrane and pressure on permeate flux and retention of lactose/lactic acid was also reported in this paper.

  15. Recovery of lactic acid from simultaneous saccharification and fermentation media using anion exchange resins.

    Science.gov (United States)

    Moldes, A B; Alonso, J L; Parajó, J C

    2003-07-01

    The physicochemical properties (capacity, kinetics and selectivity) of the ion exchange resins Amberlite IRA900, IRA400, IRA96 and IRA67 were determined to evaluate their comparative suitability for lactic acid recovery. Both the kinetics of lactic acid sorption from aqueous solutions and the equilibrium were assessed using mathematical models, which provided a close interpretation of the experimental results. The best resins (Amberlite IRA96 and IRA67) were employed in further fixed-bed operation using aqueous lactic acid solutions as feed. In this set of experiments, parameters such as capacity, regenerant consumption, percentage of lactic acid recovery and product concentration were measured. Amberlite IRA67, a weak base resin, was selected for lactic acid recovery from SSF (simultaneous saccharification and fermentation) broths. Owing to the presence of nutrients and ions other than lactate, a slightly decreased capacity was determined when using SSF media instead aqueous lactic acid solutions, but quantitative lactic acid recoveries at constant capacities were obtained in four sequential load/regeneration cycles.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. 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.

  18. Poly(lactic-co-glycolic acid) conduit for repair of injured sciatic nerve: A mechanical analysis.

    Science.gov (United States)

    Yu, Tao; Zhao, Changfu; Li, Peng; Liu, Guangyao; Luo, Min

    2013-07-25

    Tensile stress and tensile strain directly affect the quality of nerve regeneration after bridging nerve defects by poly(lactic-co-glycolic acid) conduit transplantation and autogenous nerve grafting for sciatic nerve injury. This study collected the sciatic nerve from the gluteus maximus muscle from fresh human cadaver, and established 10-mm-long sciatic nerve injury models by removing the ischium, following which poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts were transplanted. Scanning electron microscopy revealed that the axon and myelin sheath were torn, and the vessels of basilar membrane were obstructed in the poly(lactic-co-glycolic acid) conduit-repaired sciatic nerve following tensile testing. There were no significant differences in tensile tests with autogenous nerve graft-repaired sciatic nerve. Following poly(lactic-co-glycolic acid) conduit transplantation for sciatic nerve repair, tensile test results suggest that maximum tensile load, maximum stress, elastic limit load and elastic limit stress increased compared with autogenous nerve grafts, but elastic limit strain and maximum strain decreased. Moreover, the tendencies of stress-strain curves of sciatic nerves were similar after transplantation of poly(lactic-co-glycolic acid) conduits or autogenous nerve grafts. Results showed that after transplantation in vitro for sciatic nerve injury, poly(lactic-co-glycolic acid) conduits exhibited good intensity, elasticity and plasticity, indicating that poly(lactic-co-glycolic acid) conduits are suitable for sciatic nerve injury repair.

  19. Degradation and miscibility of poly(DL-lactic acid)/poly(glycolic acid) composite films: Effect of poly(DL-lactic-co-glycolic acid)

    Indian Academy of Sciences (India)

    Zhigang Ma; Na Zhao; Chengdong Xiong

    2012-08-01

    The in vitro degradation behaviour of poly(glycolic acid) (PGA) and its composite films containing poly(DL-lactic acid) (PDLLA) and poly(DL-lactic-co-glycolic acid) (PDLGA) were investigated via mass loss, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). All the films were prepared by solution casting, using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. Since the degradation rate of PDLLA is lower than that of PGA, those of the PDLLA/PGA composite films decreased. As a compatibilizer, PDLGA improved the compatibility and hydrolytic stability of PDLLA/PGA composite films. Changes in the composite films indicate that this kind of PGA-based composite biomaterial may be applicable to device design for clinical application in the future.

  20. Characterisation of lactic acid bacteria isolated from fermented milk "laban".

    Science.gov (United States)

    Chammas, Gisele I; Saliba, Rachad; Corrieu, Georges; Béal, Catherine

    2006-07-01

    The technological properties of 96 lactic acid bacteria isolated from Lebanese traditional fermented milk "laban" were characterised. They were classified by phenotypic and biochemical analyses as Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, thus indicating that laban is a fermented milk similar to yogurt. Most strains of L. bulgaricus (87.5%) exhibited a high acidification activity, whereas strains of streptococci showed low acidification ability. 33.3% of streptococci strains and 25% of lactobacilli strains displayed similar acidification performances as European strains. Results obtained for syneresis, texture and rheological parameters led us to consider that isolated strains were not low polymer-producing strains. Some of them displayed interesting characteristics such as low syneresis and high values for rheological parameters. The major flavour compounds found in pure cultures were acetaldehyde, acetone, 2-butanone, dimethyl disulfide, acetoin, 2,3-butanedione, 2,3-pentanedione, and acetic, hexanoic and butanoic acids. Acetaldehyde (7.4%) and organic acids (48.3%) were mainly produced by L. bulgaricus strains, whereas streptococci cultures contained high relative levels of 2,3-butanedione and acetoin, which represented around 82% of the total flavour compounds. Finally, strains isolated from laban samples exhibited different technological properties than those used in yogurt production, thus conferring specific characteristics to this product.

  1. A simple and robust method for pre-wetting poly (lactic-co-glycolic) acid microspheres

    OpenAIRE

    Wright, Bernice; Parmar, Nina; Bozec, Laurent; Aguayo, Sebastian D; Day, Richard M

    2015-01-01

    Poly (lactic-co-glycolic) acid microspheres are amenable to a number of biomedical procedures that support delivery of cells, drugs, peptides or genes. Hydrophilisation or wetting of poly (lactic-co-glycolic) acid are an important pre-requisites for attachment of cells and can be achieved via exposure to plasma oxygen or nitrogen, surface hydrolysis with NaOH or chloric acid, immersion in ethanol and water, or prolonged incubation in phosphate buffered saline or cell culture medium. The aim o...

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

    OpenAIRE

    Abdullah Abdullah

    2012-01-01

    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 ...

  3. Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane.

    Science.gov (United States)

    Alakomi, H L; Skyttä, E; Saarela, M; Mattila-Sandholm, T; Latva-Kala, K; Helander, I M

    2000-05-01

    The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl(2). Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosa was effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.

  4. Occurrence of Arginine Deiminase Pathway Enzymes in Arginine Catabolism by Wine Lactic Acid Bacteria

    OpenAIRE

    Liu., S; Pritchard, G. G.; Hardman, M. J.; Pilone, G. J.

    1995-01-01

    l-Arginine, an amino acid found in significant quantities in grape juice and wine, is known to be catabolized by some wine lactic acid bacteria. The correlation between the occurrence of arginine deiminase pathway enzymes and the ability to catabolize arginine was examined in this study. The activities of the three arginine deiminase pathway enzymes, arginine deiminase, ornithine transcarbamylase, and carbamate kinase, were measured in cell extracts of 35 strains of wine lactic acid bacteria....

  5. Lactic acid fermentation in vegetable juices supplemented with different content of brewer’s yeast autolysate

    Directory of Open Access Journals (Sweden)

    Rakin Marica B.

    2005-01-01

    Full Text Available The work is concerned with the conditions for lactic acid fermentation in a mixture of beetroot (Beta vulgaris L juice and carrot (Daucus carota L juice and different content of brewer’s yeast autolysate with Lactobacillus plantarum A112 and with Lactobacillus acidophilus NCDO 1748.Both cultures showed good biochemical activity in these mixtures. The production of lactic acid has been stimulated using the higher content of brewer’s yeast autolysate. In these mixtures, L. plantarum A112 has shown better growth and lactic acid production than L. acidophilus NCDO 1748.

  6. Anaerobic fermentative production of lactic acid using cheese whey and corn steep liquor.

    Science.gov (United States)

    Agarwal, Lata; Dutt, Kakoli; Meghwanshi, Gautam K; Saxena, R K

    2008-04-01

    Cheese whey was the most suitable substrate for production of lactic acid under anaerobic conditions by Entercoccus flavescens which, on supplementating with corn steep liquor (5% v/v) and 10 mM CaCO(3) at pH 5.5, 37 degrees C, yielded 12.6 g lactic acid/l in 36 h. Production was scaled up to a 10 l bioreactor under controlled pH and continuous CO(2) supply and gave 28 g lactic acid/l in 30 h resulting in a net 8.7-fold increase in production as compared to unoptimized conditions.

  7. Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.

    Science.gov (United States)

    Fritsch, Caroline; Heinrich, Veronika; Vogel, Rudi F; Toelstede, Simone

    2016-08-01

    Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes.

  8. Separation of lactic acid from acetic acid using a four-zone SMB.

    Science.gov (United States)

    Lee, Ho-Joon; Xie, Yi; Koo, Yoon-Mo; Wang, Nien-Hwa Linda

    2004-01-01

    A simulated moving bed (SMB) process has been developed to separate l-(+)-lactic acid from acetic acid, a major impurity in the fermentation broth of Lactobacillus rhamnosus. Poly(4-vinylpyridine) resin (PVP) was selected as the adsorbent. Adsorption isotherms and mass transfer parameters of the organic acids were estimated from single-column frontal tests. Experimental results show that the Langmuir isotherms obtained from the frontal tests can be used in the design of an SMB process to achieve 99.9% purity and over 93% yield of lactic acid. The column profiles and effluent histories, however, deviate from rate model predictions based on the Langmuir isotherms. They agree more closely with the predictions based on a modified Langmuir isotherm for lactic acid. The standing wave design method for systems with modified Langmuir isotherms is developed in this study. Rate model simulations show that the process based on the modified design method can achieve high purity (>99.9%) and high yield (>99.9%). For this nonlinear system, accurate isotherm model and model parameters are needed in the design, and the zone flow rates must be closely monitored and controlled in order to ensure high purity and high yield in the SMB process.

  9. Acid hydrolysis of Curcuma longa residue for ethanol and lactic acid fermentation.

    Science.gov (United States)

    Nguyen, Cuong Mai; Nguyen, Thanh Ngoc; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Park, Youn-Je; Kim, Jin-Cheol

    2014-01-01

    This research examines the acid hydrolysis of Curcuma longa waste, to obtain the hydrolysate containing lactic acid and ethanol fermentative sugars. A central composite design for describing regression equations of variables was used. The selected optimum condition was 4.91% sulphuric acid, 122.68°C and 50 min using the desirability function under the following conditions: the maximum reducing sugar (RS) yield is within the limited range of the 5-hydroxymethylfurfural (HMF) and furfural concentrations. Under the condition, the obtained solution contained 144 g RS/L, 0.79 g furfural/L and 2.59 g HMF/L and was directly fermented without a detoxification step. The maximum product concentration, average productivity, RS conversion and product yield were 115.36 g/L, 2.88 g/L/h, 89.43% and 64% for L-lactic acid; 113.92 g/L, 2.59 g/L/h, 88.31% and 63.29% for D-lactic acid; and 55.03 g/L, 1.38 g/L/h, 42.66 and 30.57%, respectively, for ethanol using a 7-L jar fermenter.

  10. Acetate accumulation enhances mixed culture fermentation of biomass to lactic acid.

    Science.gov (United States)

    Khor, Way Cern; Roume, Hugo; Coma, Marta; Vervaeren, Han; Rabaey, Korneel

    2016-10-01

    Lactic acid is a high-in-demand chemical, which can be produced through fermentation of lignocellulosic feedstock. However, fermentation of complex substrate produces a mixture of products at efficiencies too low to justify a production process. We hypothesized that the background acetic acid concentration plays a critical role in lactic acid yield; therefore, its retention via selective extraction of lactic acid or its addition would improve overall lactic acid production and eliminate net production of acetic acid. To test this hypothesis, we added 10 g/L of acetate to fermentation broth to investigate its effect on products composition and concentration and bacterial community evolution using several substrate-inoculum combinations. With rumen fluid inoculum, lactate concentrations increased by 80 ± 12 % (cornstarch, p 69 % lactic acid bacteria (LAB), predominantly Lactobacillaceae. Higher acetate concentration promoted a more diverse LAB population, especially on non-inoculated bottles. In subsequent tests, acetate was added in a semi-continuous percolation system with grass as substrate. These tests confirmed our findings producing lactate at concentrations 26 ± 5 % (p lactic acid production from waste biomass to levels more attractive for application.

  11. Assessing physio-macromolecular effects of lactic acid on Zygosaccharomyces bailii cells during microaerobic fermentation.

    Science.gov (United States)

    Kuanyshev, Nurzhan; Ami, Diletta; Signori, Lorenzo; Porro, Danilo; Morrissey, John P; Branduardi, Paola

    2016-08-01

    The ability of Zygosaccharomyces bailii to grow at low pH and in the presence of considerable amounts of weak organic acids, at lethal condition for Saccharomyces cerevisiae, increased the interest in the biotechnological potential of the yeast. To understand the mechanism of tolerance and growth effect of weak acids on Z. bailii, we evaluated the physiological and macromolecular changes of the yeast exposed to sub lethal concentrations of lactic acid. Lactic acid represents one of the important commodity chemical which can be produced by microbial fermentation. We assessed physiological effect of lactic acid by bioreactor fermentation using synthetic media at low pH in the presence of lactic acid. Samples collected from bioreactors were stained with propidium iodide (PI) which revealed that, despite lactic acid negatively influence the growth rate, the number of PI positive cells is similar to that of the control. Moreover, we have performed Fourier Transform Infra-Red (FTIR) microspectroscopy analysis on intact cells of the same samples. This technique has been never applied before to study Z. bailii under this condition. The analyses revealed lactic acid induced macromolecular changes in the overall cellular protein secondary structures, and alterations of cell wall and membrane physico-chemical properties.

  12. Process development and optimisation of lactic acid purification using electrodialysis.

    Science.gov (United States)

    Madzingaidzo, L; Danner, H; Braun, R

    2002-07-03

    Cell free sodium lactate solutions were subjected to purification based on mono- and bi-polar electrodialysis. Lactate concentration in the product stream increased to a maximum of 15% during mono-polar electrodialysis. Stack energy consumption averaged 0.6 kW h kg(-1) lactate transported at current efficiencies in the 90% range. Under optimum feed concentration (125 g l(-1)) and process conditions (auto-current mode with conductivity setpoints of minimum 5 and maximum 40 mS cm(-1)), lactate flux reached 300 g m(-2) h(-1) and water flux were low for mono-polar electrodialysis averaging 0.3 kg H(2)O per M lactate transported. Glucose in the concentrate stream solutions was reduced to concentrate stream solutions. After mono-polar electrodialysis, the concentrated sodium lactate solutions were further purified using bi-polar electrodialysis. Water transport during bi-polar electrodialysis reached figures of 0.070 - 0.222 kg H(2)O per M lactate. Free lactic acid concentration reached 16% with lactate flux of up to 300 g m(-2) h(-1). Stack energy consumption ranged from 0.6 to 1 kW h per kg lactate. Under optimised process conditions current efficiency during bi-polar electrodialysis was consistently around 90%. Glucose was further reduced from 2 to solution. Acetic acid impurity remained at around 1 g l(-1). Significant reduction in colour and minerals in the product streams was observed during electrodialysis purification.

  13. Biodegradation of flax fiber reinforced poly lactic acid

    Directory of Open Access Journals (Sweden)

    2010-07-01

    Full Text Available Woven and nonwoven flax fiber reinforced poly lactic acid (PLA biocomposites were prepared with amphiphilic additives as accelerator for biodegradation. The prepared composites were buried in farmland soil for biodegradability studies. Loss in weight of the biodegraded composite samples was determined at different time intervals. The surface morphology of the biodegraded composites was studied with scanning electron microscope (SEM. Results indicated that in presence of mandelic acid, the composites showed accelerated biodegradation with 20–25% loss in weight after 50–60 days. On the other hand, in presence of dicumyl peroxide (as additive, biodegradation of the composites was relatively slow as confirmed by only 5–10% loss in weight even after 80–90 days. This was further confirmed by surface morphology of the biodegraded composites. We have attempted to show that depending on the end uses, we can add different amphiphilic additives for delayed or accelerated biodegradability. This work gives us the idea of biodegradation of materials from natural fiber reinforced PLA composites when discarded carelessly in the environment instead of proper waste disposal site.

  14. Bacteriocins from lactic acid bacteria: production, purification, and food applications.

    Science.gov (United States)

    De Vuyst, Luc; Leroy, Frédéric

    2007-01-01

    In fermented foods, lactic acid bacteria (LAB) display numerous antimicrobial activities. This is mainly due to the production of organic acids, but also of other compounds, such as bacteriocins and antifungal peptides. Several bacteriocins with industrial potential have been purified and characterized. The kinetics of bacteriocin production by LAB in relation to process factors have been studied in detail through mathematical modeling and positive predictive microbiology. Application of bacteriocin-producing starter cultures in sourdough (to increase competitiveness), in fermented sausage (anti-listerial effect), and in cheese (anti-listerial and anti-clostridial effects), have been studied during in vitro laboratory fermentations as well as on pilot-scale level. The highly promising results of these studies underline the important role that functional, bacteriocinogenic LAB strains may play in the food industry as starter cultures, co-cultures, or bioprotective cultures, to improve food quality and safety. In addition, antimicrobial production by probiotic LAB might play a role during in vivo interactions occurring in the human gastrointestinal tract, hence contributing to gut health.

  15. Lactic acid bacterial extract as a biogenic mineral growth modifier

    Science.gov (United States)

    Borah, Ballav M.; Singh, Atul K.; Ramesh, Aiyagari; Das, Gopal

    2009-04-01

    The formation of minerals and mechanisms by which bacteria could control their formation in natural habitats is now of current interest for material scientists to have an insight of the mechanism of in vivo mineralization, as well as to seek industrial and technological applications. Crystalline uniform structures of calcium and barium minerals formed micron-sized building blocks when synthesized in the presence of an organic matrix consisting of secreted protein extracts from three different lactic acid bacteria (LAB) viz.: Lactobacillus plantarum MTCC 1325, Lactobacillus acidophilus NRRL B4495 and Pediococcus acidilactici CFR K7. LABs are not known to form organic matrix in biological materialization processes. The influence of these bacterial extracts on the crystallization behavior was investigated in details to test the basic coordination behavior of the acidic protein. In this report, varied architecture of the mineral crystals obtained in presence of high molecular weight protein extracts of three different LAB strains has been discussed. The role of native form of high molecular weight bacterial protein extracts in the generation of nucleation centers for crystal growth was clearly established. A model for the formation of organic matrix-cation complex and the subsequent events leading to crystal growth is proposed.

  16. Production of L-lactic acid from a mixture of xylose and glucose by co-cultivation of lactic acid bacteria.

    Science.gov (United States)

    Taniguchi, M; Tokunaga, T; Horiuchi, K; Hoshino, K; Sakai, K; Tanaka, T

    2004-12-01

    The production of optically pure lactic acid in a high yield from xylose or a mixture of xylose and glucose, which is a model hydrolysate of lignocellulose, is described. In a single cultivation, Enterococcus casseliflavus produced 38 g/l of lactic acid with an optical purity of 96% enantiomeric excess (ee) and 6.4 g/l of acetic acid from 50 g/l of xylose when MRS medium was used. When a mixture of 50 g/l of xylose and 100 g/l of glucose was used as the carbon source in a cultivation of E. casseliflavus alone, glucose was converted to lactic acid in the early phase of the cultivation but xylose was hardly consumed. In a co-cultivation where E. casseliflavus and Lactobacillus casei specific for glucose were simultaneously inoculated, little or no lactic acid was produced after the glucose was almost consumed. A co-cultivation with two-stage inoculation (in which E. casseliflavus was added at a cultivation time of 40 h after L. casei cells were inoculated) resulted in complete consumption of 50 g/l of xylose and 100 g/l of glucose. In the co-cultivation, 95 g/l of lactic acid with a high optical purity of 96% ee was obtained at 192 h. Such a co-cultivation using two microorganisms specific for each sugar is considered to be one promising cultivation technique for the efficient production of lactic acid from a sugar mixture derived from lignocellulose.

  17. Efficient production of optically pure L-lactic acid from food waste at ambient temperature by regulating key enzyme activity.

    Science.gov (United States)

    Li, Xiang; Chen, Yinguang; Zhao, Shu; Chen, Hong; Zheng, Xiong; Luo, Jinyang; Liu, Yanan

    2015-03-01

    Bio-production of optically pure L-lactic acid from food waste has attracted much interest as it can treat organic wastes with simultaneous recovery of valuable by-products. However, the yield of L-lactic acid was very low and no optically pure L-lactic acid was produced in the literature due to (1) the lower activity of enzymes involved in hydrolysis and L-lactic acid generation, and (2) the participation of other enzymes related to D-lactic acid and acetic and propionic acids production. In this paper, a new strategy was reported for effective production of optically pure L-lactic acid from food waste at ambient temperature, i.e. via regulating key enzyme activity by sewage sludge supplement and intermittent alkaline fermentation. It was found that not only optically pure L-lactic acid was produced, but the yield was enhanced by 2.89-fold. The mechanism study showed that the activities of enzymes relevant to food waste hydrolysis and lactic acid production were enhanced, and the key enzymes related to volatile fatty acids and D-lactic acid generations were severally decreased or inhibited. Also, the microbes responsible for L-lactic acid production were selectively proliferated. Finally, the pilot-scale continuous experiment was conducted to testify the feasibility of this new technique.

  18. Channel-mediated lactic acid transport: a novel function for aquaglyceroporins in bacteria.

    Science.gov (United States)

    Bienert, Gerd P; Desguin, Benoît; Chaumont, François; Hols, Pascal

    2013-09-15

    MIPs (major intrinsic proteins), also known as aquaporins, are membrane proteins that channel water and/or uncharged solutes across membranes in all kingdoms of life. Considering the enormous number of different bacteria on earth, functional information on bacterial MIPs is scarce. In the present study, six MIPs [glpF1 (glycerol facilitator 1)-glpF6] were identified in the genome of the Gram-positive lactic acid bacterium Lactobacillus plantarum. Heterologous expression in Xenopus laevis oocytes revealed that GlpF2, GlpF3 and GlpF4 each facilitated the transmembrane diffusion of water, dihydroxyacetone and glycerol. As several lactic acid bacteria have GlpFs in their lactate racemization operon (GlpF1/F4 phylogenetic group), their ability to transport this organic acid was tested. Both GlpF1 and GlpF4 facilitated the diffusion of D/L-lactic acid. Deletion of glpF1 and/or glpF4 in Lb. plantarum showed that both genes were involved in the racemization of lactic acid and, in addition, the double glpF1 glpF4 mutant showed a growth delay under conditions of mild lactic acid stress. This provides further evidence that GlpFs contribute to lactic acid metabolism in this species. This lactic acid transport capacity was shown to be conserved in the GlpF1/F4 group of Lactobacillales. In conclusion, we have functionally analysed the largest set of bacterial MIPs and demonstrated that the lactic acid membrane permeability of bacteria can be regulated by aquaglyceroporins.

  19. Molecular Characterization of Intrinsic and Acquired antibiotic resistance in lactic Acid bacteria and Bifidobacteria

    NARCIS (Netherlands)

    Ammor, M.S.; Flórez, A.B.; Hoek, van A.H.A.M.; Reyes-Gavilan, de los C.G.; Aarts, H.J.M.; Margolles, A.; Mayo, B.

    2008-01-01

    The minimum inhibitory concentrations (MICs) of 6 different antibiotics (chloramphenicol, clindamycin, erythromycin, streptomycin, tetracycline and vancomycin) were determined for 143 strains of lactic acid bacteria and bifidobacteria using the Etest. Different MICs were found for different species

  20. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants

    Science.gov (United States)

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Fou...

  1. Structure-function relationships of glucansucrase and fructansucrase enzymes from lactic acid bacteria

    NARCIS (Netherlands)

    Hijum, S.A.F.T. van; Kralj, S.; Ozimek, L.K.; Dijkhuizen, L.; Geel-Schutten, G.H. van

    2006-01-01

    Lactic acid bacteria (LAB) employ sucrase-type enzymes to convert sucrose into homopolysaccharides consisting of either glucosyl units (glucans) or fructosyl units (fructans). The enzymes involved are labeled glucansucrases (GS) and fructansucrases (FS), respectively. The available molecular, bioche

  2. Molecular Characterization of Intrinsic and Acquired antibiotic resistance in lactic Acid bacteria and Bifidobacteria

    NARCIS (Netherlands)

    Ammor, M.S.; Flórez, A.B.; Hoek, van A.H.A.M.; Reyes-Gavilan, de los C.G.; Aarts, H.J.M.; Margolles, A.; Mayo, B.

    2008-01-01

    The minimum inhibitory concentrations (MICs) of 6 different antibiotics (chloramphenicol, clindamycin, erythromycin, streptomycin, tetracycline and vancomycin) were determined for 143 strains of lactic acid bacteria and bifidobacteria using the Etest. Different MICs were found for different species

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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...

  5. Systematic Procedure for Integrated Process Operation: Reverse Electro-Enhanced Dialysis (REED) during Lactic Acid Fermentation

    DEFF Research Database (Denmark)

    Prado Rubio, Oscar Andres; Jørgensen, Sten Bay; Jonsson, Gunnar Eigil

    2011-01-01

    The integration of lactic acid fermentation and Reverse Electro-Enhanced Dialysis (REED) is investigated based upon previously developed mathematical models. A goal driven process and operation design procedure is proposed and partially investigated. The conceptual analysis of the processes...

  6. Leguminose green juice as an efficient nutrient for l(+)-lactic acid production.

    Science.gov (United States)

    Dietz, Donna; Schneider, Roland; Papendiek, Franka; Venus, Joachim

    2016-10-20

    Lactic acid is one of the most important building blocks for the production of bioplastic. Many investigations have been conducted to reduce the lactic acid production costs. In this work, the focus was put on the application of legume pressed juice or green juice as nutrient source. The pressed juice was utilized directly without prior pre-treatment and sterilization. Using two different alfalfa green juices and a clover green juice from two different harvest years as sole nutrients, non-sterile fermentations were performed at 52°C and pH 6.0 with a thermotolerant strain Bacillus coagulans AT107. The results showed that alfalfa green juices generally were more suitable for high lactic acid production than clover green juices, presumably due to the higher nitrogen content. A final titer of 98.8g/L after 30h with l(+)-lactic acid purity of >99% was obtained.

  7. Poly(Lactic-co-Glycolic Acid): Applications and Future Prospects for Periodontal Tissue Regeneration

    National Research Council Canada - National Science Library

    Xiaoyu Sun; Chun Xu; Gang Wu; Qingsong Ye; Changning Wang

    2017-01-01

    ... (lactic-co-glycolic acid) (PLGA), a synthetic aliphatic polyester, has been actively investigated for periodontal therapy due to its favorable mechanical properties, tunable degradation rates, and high biocompatibility...

  8. Broad-spectrum antifungal-producing lactic acid bacteria and their application in fruit models

    National Research Council Canada - National Science Library

    Crowley, Sarah; Mahony, Jennifer; van Sinderen, Douwe

    2013-01-01

    A large-scale screen of some 7,000 presumptive lactic acid bacteria (LAB), isolated from animal, human, or plant origin, identified 1,149 isolates with inhibitory activity against the food-spoilage mould Penicillium expansum...

  9. Recombinant lactobacillus for fermentation of xylose to lactic acid and lactate

    Energy Technology Data Exchange (ETDEWEB)

    Picataggio, Stephen K. (Golden, CO); Zhang, Min (Lakewood, CO); Franden, Mary Ann (Littleton, CO); Mc Millan, James D. (Boulder, CO); Finkelstein, Mark (Fort Collins, CO)

    1998-01-01

    A recombinant Lactobacillus MONT4 is provided which has been genetically engineered with xylose isomerase and xylulokinase genes from Lactobacillus pentosus to impart to the Lactobacillus MONT4 the ability to ferment lignocellulosic biomass containing xylose to lactic acid.

  10. Recent trends in lactic acid biotechnology: A brief review on production to purification

    Directory of Open Access Journals (Sweden)

    Tayyba Ghaffar

    2014-04-01

    Full Text Available Lactic acid is one of the most important organic acid which is being extensively used around the globe in a range of industrial and biotechnological applications. From its very old history to date, many methods have been introduced to improve the optimization of lactic acid to get highest yields of the product of industrial interests. In serious consideration of the worldwide economic and lactic acid consumption issues there has been increasing research interest in the value of materials with natural origin, which are cheap, abundant and easily available all around the year. Recent trends showed that lactic acid production through fermentation is advantageous over chemical due to the environmental concerns of the modern world. The eco-friendly processing and fermentable capability of many of the agricultural and agro-industrial based raw materials or by-products respectively makes them attractive candidates in fermentation biotechnology to produce a value-added product with multiple applications. In fact, major advances have already been achieved in recent years in order to get pure lactic acid with optimal yield. The present review work is summarized on the multi-step processing technologies to produce lactic acid from different substances as a starting material potentially from various agro-industrial based biomasses. The information is also given on a purification through schematic representation of the product of quality interests.

  11. 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.

  12. 16 years research on lactic acid production with yeast - ready for the market?

    Science.gov (United States)

    Sauer, Michael; Porro, Danilo; Mattanovich, Diethard; Branduardi, Paola

    2010-01-01

    The use of plastic produced from non-renewable resources constitutes a major environmental problem of the modern society. Polylactide polymers (PLA) have recently gained enormous attention as one possible substitution of petroleum derived polymers. A prerequisite for high quality PLA production is the provision of optically pure lactic acid, which cannot be obtained by chemical synthesis in an economical way. Microbial fermentation is therefore the commercial option to obtain lactic acid as monomer for PLA production. However, one major economic hurdle for commercial lactic acid production as basis for PLA is the costly separation procedure, which is needed to recover and purify the product from the fermentation broth. Yeasts, such as Saccharomyces cerevisiae (bakers yeast) offer themselves as production organisms because they can tolerate low pH and grow on mineral media what eases the purification of the acid. However, naturally yeasts do not produce lactic acid. By metabolic engineering, ethanol was exchanged with lactic acid as end product of fermentation. A vast amount of effort has been invested into the development of yeasts for lactic acid production since the first paper on this topic by Dequin and Barre appeared 1994. Now yeasts are very close to industrial exploitation - here we summarize the developments in this field.

  13. Production of D-lactic acid in a continuous membrane integrated fermentation reactor by genetically modified Saccharomyces cerevisiae: enhancement in D-lactic acid carbon yield.

    Science.gov (United States)

    Mimitsuka, Takashi; Sawai, Kenji; Kobayashi, Koji; Tsukada, Takeshi; Takeuchi, Norihiro; Yamada, Katsushige; Ogino, Hiroyasu; Yonehara, Tetsu

    2015-01-01

    Poly d-lactic acid is an important polymer because it improves the thermostability of poly l-lactic acid by stereo complex formation. To demonstrate potency of continuous fermentation using a membrane-integrated fermentation reactor (MFR) system, continuous fermentation using genetically modified Saccharomyces cerevisiae which produces d-lactic acid was performed at the low pH and microaerobic conditions. d-Lactic acid continuous fermentation using the MFR system by genetically modified yeast increased production rate by 11-fold compared with batch fermentation. In addition, the carbon yield of d-lactic acid in continuous fermentation was improved to 74.6 ± 2.3% compared to 39.0 ± 1.7% with batch fermentation. This dramatic improvement in carbon yield could not be explained by a reduction in carbon consumption to form cells compared to batch fermentation. Further detailed analysis at batch fermentation revealed that the carbon yield increased to 76.8% at late stationary phase. S. cerevisiae, which exhibits the Crabtree-positive effect, demonstrated significant changes in metabolic activities at low sugar concentrations (Rossignol et al., Yeast, 20, 1369-1385, 2003). Moreover, lactate-producing S. cerevisiae requires ATP supplied not only from the glycolytic pathway but also from the TCA cycle (van Maris et al., Appl. Environ. Microbiol., 70, 2898-2905, 2004). Our finding was revealed that continuous fermentation, which can maintain the conditions of both a low sugar concentration and air supply, results in Crabtree-positive and lactate-producing S. cerevisiae for suitable conditions of d-lactic acid production with respect to redox balance and ATP generation because of releasing the yeast from the Crabtree effect.

  14. Extracellular protease derived from lactic acid bacteria stimulates the fermentative lactic acid production from the by-products of rice as a biomass refinery function.

    Science.gov (United States)

    Watanabe, Masanori; Techapun, Charin; Kuntiya, Ampin; Leksawasdi, Noppol; Seesuriyachan, Phisit; Chaiyaso, Thanongsak; Takenaka, Shinji; Maeda, Isamu; Koyama, Masahiro; Nakamura, Kozo

    2017-02-01

    A lactic acid producing bacterium, Lactobacillus rhamnosus M-23, newly isolated from a rice washing drainage storage tank was found to produce l-(+)-lactic acid from a non-sterilized mixture of rice washing drainage and rice bran without any additions of nutrients under the simultaneous saccharification and fermentation (SSF) process. This strain has the ability to utilize the non-sterilized rice washing drainage and rice bran as a source of carbohydrate, saccharifying enzymes and nutrients for lactic acid production. Observation of extracellular protease activity in SSF culture broth showed that a higher protease activity was present in strain M-23 than in other isolated lactic acid producing bacteria (LABs). To investigate the structural changes of solid particles of rice washing drainage throughout LAB cultivation, scanning electron microscopic (SEM) observation and Fourier transform infrared-spectroscopy (FT-IR) analysis were performed. The results of the SEM observation showed that the surface material could be removed from solid particles of rice washing drainage treated by culture broth (supernatant) of strain M-23, thus exposing the crystal structure of the starch particle surface. The results of the FT-IR analysis revealed that the specific transmittance decrease of the CC and CO stretching and OH group of the solid particles of the rice washing drainage were highly correlated with the produced lactic acid concentration and extracellular protease activity, respectively. These results demonstrate the high lactic acid producing ability of strain M-23 from a non-sterilized mixture of rice washing drainage and rice bran under the SSF condition due to the removal of proteinaceous material and exposure of the starch particle surface by extracellular protease.

  15. Synthesis and Characterization of Chitosan-g-poly(D, L-lactic acid) Copolymer

    Institute of Scientific and Technical Information of China (English)

    Hua YANG; Shao Bing ZHOU; Xian Mo DENG

    2005-01-01

    Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.

  16. The ability of Clostridium bifermentans strains to lactic acid biosynthesis in various environmental conditions

    OpenAIRE

    Leja, Katarzyna; Myszka, Kamila; Czaczyk, Katarzyna

    2013-01-01

    Clostridium bifermentans strains, isolated from a manure, were examinated for their ability to produce lactic acid from PY medium with glycerol under different pH conditions and when PY medium was supplemented with saccharides such as fructose, sorbitol, glucose, mannose, mannitol, maltose, xylose, raffinose, and arabinose. In the last test performed, the ability of investigated strains to produce lactic acid from mixed carbon source (glycerol plus saccharide) was checked. The strains of Cl. ...

  17. Synthesis and characterization of new biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ~(31)p NMR,~1H NMR,~(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated....

  18. ISOLATION OF LACTIC ACID BACTERIA UNDER LOW TEMPERATURE FOR THE PREPARATION OF YOGURT

    OpenAIRE

    Javid Ahmad Bhat; Mohd Irfan Naik; R.K. Tenguria

    2014-01-01

    An investigation of isolation of Lactic acid bacteria was carried out under low temperature for the preparation of Yogurt by using various food supplements like carrot, ground-nut and tomato juices. Methods: Various samples of Cow milk, Skimmed milk were processed along with nutrients like Carrot, ground nut and tomato juices with Tryptone glucose yeast extract agar (TGYA) at different temperatures like 50C, 150C and 220C for the isolation of Lactic acid bacteria for the preparation of yogurt...

  19. ISOLATION AND IDENTIFICATION OF LACTIC ACID PRODUCING BACTERIA FROM CAMEL MILK

    OpenAIRE

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

    2002-01-01

    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 cam...

  20. Cell wall structure and function in lactic acid bacteria.

    Science.gov (United States)

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2014-08-29

    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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

    2015-03-01

    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.

  3. Isolation of alkaliphilic bacteria for production of high optically pure L-(+)-lactic acid.

    Science.gov (United States)

    Yokaryo, Hiroto; Tokiwa, Yutaka

    2014-01-01

    Lactic acid bacteria that grow under alkaline conditions (pH 10) were isolated from various sources in Okinawa (Japan). These alkali-tolerant and alkaliphilic bacteria were classified as follows: Microbacterium sp. (1 strain), Enterococcus spp. (9 strains), Alkalibacterium spp. (3 strains), Exiguobacterium spp. (5 strains), Oceanobacillus spp. (3 strains) and Bacillus spp. (7 strains) by 16S rRNA gene sequencing. By fermentation, many strains were able to convert glucose into mainly L-(+)-lactic acid of high optical purity in alkaline broth. This result indicated that valuable L-(+)-lactic acid-producing bacteria could be isolated efficiently by screening under alkaline conditions. Six strains were selected and their ability to produce lactic acid at different initial pH was compared. Enterococcus casseliflavus strain 79w3 gave the highest lactic acid concentration. Lactic acid concentration and productivity were 103 g L(-1) (optical purity of 99.5% as L-isomer) and 2.2 g L(-1) h(-1), respectively when 129 g L(-1) of glucose was used by batch fermentation.

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

    Directory of Open Access Journals (Sweden)

    Daneysa Lahis Kalschne

    2015-03-01

    Full Text Available 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.

  5. Lactic acid production from cellobiose and xylose by engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Turner, Timothy L; Zhang, Guo-Chang; Oh, Eun Joong; Subramaniam, Vijay; Adiputra, Andrew; Subramaniam, Vimal; Skory, Christopher D; Jang, Ji Yeon; Yu, Byung Jo; Park, In; Jin, Yong-Su

    2016-05-01

    Efficient and rapid production of value-added chemicals from lignocellulosic biomass is an important step toward a sustainable society. Lactic acid, used for synthesizing the bioplastic polylactide, has been produced by microbial fermentation using primarily glucose. Lignocellulosic hydrolysates contain high concentrations of cellobiose and xylose. Here, we constructed a recombinant Saccharomyces cerevisiae strain capable of fermenting cellobiose and xylose into lactic acid. Specifically, genes (cdt-1, gh1-1, XYL1, XYL2, XYL3, and ldhA) coding for cellobiose transporter, β-glucosidase, xylose reductase, xylitol dehydrogenase, xylulokinase, and lactate dehydrogenase were integrated into the S. cerevisiae chromosomes. The resulting strain produced lactic acid from cellobiose or xylose with high yields. When fermenting a cellulosic sugar mixture containing 10 g/L glucose, 40 g/L xylose, and 80 g/L cellobiose, the engineered strain produced 83 g/L of lactic acid with a yield of 0.66 g lactic acid/g sugar (66% theoretical maximum). This study demonstrates initial steps toward the feasibility of sustainable production of lactic acid from lignocellulosic sugars by engineered yeast.

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

    Institute of Scientific and Technical Information of China (English)

    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 × 1015 ions/cm2. 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~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.

  7. Kefir immobilized on corn grains as biocatalyst for lactic acid fermentation and sourdough bread making.

    Science.gov (United States)

    Plessas, Stavros; Alexopoulos, Athanasios; Bekatorou, Argyro; Bezirtzoglou, Eugenia

    2012-12-01

    The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at various temperatures. The immobilized cells increased the fermentation rate and enhanced lactic acid production compared to free kefir cells. Maximum lactic acid yield (68.8 g/100 g) and lactic acid productivity (12.6 g/L per day) were obtained during fermentation by immobilized cells at 37 °C. The immobilized biocatalyst was then assessed as culture for sourdough bread making. The produced sourdough breads had satisfactory specific loaf volumes and good sensory characteristics. Specifically, bread made by addition of 60% w/w sourdough containing kefir immobilized on corn was more resistant regarding mould spoilage (appearance during the 11(th) day), probably due to higher lactic acid produced (2.86 g/Kg of bread) compared to the control samples. The sourdough breads made with the immobilized biocatalyst had aroma profiles similar to that of the control samples as shown by headspace SPME GC-MS analysis.

  8. The effects of a food product containing lactic acid on the activity of acetylcholinesterase

    Directory of Open Access Journals (Sweden)

    Andre-Michael Beer

    2012-06-01

    Full Text Available Objective: Patients reported that a food product containing lactic acid improved their memory and thought processes. The ingredients of the tested food product are compound substances and smooth muscle fibre, the appropriate medium in which to analyse their effects. Acetylcholinesterase inhibitors are used to treat memory loss and failing thought performance. The aim of this study was to compare the effects of the lactic acid food product with the effects of acetylcholinesterase inhibitors. Methods: In this in vitro study the effects of the food product containing lactic acid on smooth muscle fibres of guinea pig stomach were investigated. Results: The results show that the lactic acid food product contains substances that can inhibit the activity of both acetylcholinesterase and butyrylcholinesterase. This inhibitory effect was compared to the inhibitory effects of galantamine (Nivalin®, pyridostigmine bromide (Kalymin® and donepezil hydrochloride (Donepezil®, which are clinically used for the pharmacological treatment of dementia. We observed a 5% to 20% less potency factor difference with the lactic acid food product compared to that of the pharmaceutical drugs. Conclusions: This proves that the lactic acid food product can also have an impact on memory and thought performance and that these results should promote clinical trials to test efficacy. [J Exp Integr Med 2012; 2(3.000: 207-212

  9. Effect of Skimmed-Milk and Starter Addition on Lactic Acid Formation in Soyghurt

    Directory of Open Access Journals (Sweden)

    Yanna Syamsuddin

    2013-01-01

    Full Text Available Research on Effect of Skimmed-Milk and Starter Addition on Lactic Acid Formation in Soyghurt has been done. Soyghurt is a probiotic drinking product made from soy-milk produced by fermentation process using lactic acid bacteria. The bacteria used as starter was Lactobacillus bulgaricus and Streptococcus thermophillus. The objective of this research was to evaluate the effect of skimmed-milk and starter addition on the formation of lactic acid. Variables used in this research was skimmed-milk concentration of 5, 10, and 15% and starter concentration of 3, 5, and 7%, based on volume of soy-milk used as raw material. The soy-milk used was analyzed for its carbohydrate and protein content, and the soyghurt produced was analyzed for its lactic acid, pH and syneresis. The result showed that carbohydrate and protein content in soy-milk was 122.39 mg/L and 2.75%, respectively. The best condition of this process was the addition of 15% skimmed-milk and 5% starter, which yielded the highest lactic acid of 15% with pH of 4.23 and syneresis of 15%. It can be concluded that increasing skimmed-milk concentration cause the increase in lactic acid formation and decrease pH and syneresis. While effect of starter concentration on product analysis was influenced by the amount of nutrition contain in soy-milk.

  10. 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.

  11. Kinetic modeling of lactic acid production from batch submerged fermentation of cheese whey

    Energy Technology Data Exchange (ETDEWEB)

    Tango, M.S.A.; Ghaly, A.E.

    1999-12-01

    A kinetic model for the production of lactic acid through batch submerged fermentation of cheese whey using Lactobacillus helveticus was developed. The model accounts for the effect of substrate limitation, substrate inhibition, lactic acid inhibition, maintenance energy and cell death on the cell growth, substrate utilization, and lactic acid production during the fermentation process. The model was evaluated using experimental data from Tango and Ghaly (1999). The predicted results obtained from the model compared well with experimental (R{sup 2} = 0.92--0.98). The model was also used to investigate the effect of the initial substrate concentration on the lag period, fermentation time, specific growth rate, and cell productivity during batch fermentation. The maximum specific growth rate ({micro}{sub m}), the saturation constant (K{sub S}), the substrate inhibition constant (K{sub IS}), and the lactic acid inhibition constant (K{sub IP}) were found to be 0.25h{sup {minus}1}, 0.9 g/L, 250.0 g/L, and 60.0 g/L, respectively. High initial lactose concentration in cheese whey reduced both the specific growth rate and substrate utilization rate due to the substrate inhibition phenomenon. The maximum lactic acid production occurred at about 100 g/L initial lactose concentration after 40 h of fermentation. The maximum lactic acid concentration above which Lactobacillus helveticus did not grow was found to be 80.0 g/L.

  12. Effect of fermentation conditions on L-lactic acid production from soybean straw hydrolysate.

    Science.gov (United States)

    Wang, Juan; Wang, Qunhui; Xu, Zhong; Zhang, Wenyu; Xiang, Juan

    2015-01-01

    Four types of straw, namely, soybean, wheat, corn, and rice, were investigated for use in lactic acid production. These straws were mainly composed of cellulose, hemicellulose, and lignin. After pretreatment with ammonia, the cellulose content increased, whereas the hemicellulose and lignin contents decreased. Analytical results also showed that the liquid enzymatic hydrolysates were primarily composed of glucose, xylose, and cellobiose. Preliminary experiments showed that a higher lactic acid concentration could be obtained from the wheat and soybean straw. However, soybean straw was chosen as the substrate for lactic acid production owing to its high protein content. The maximum lactic acid yield (0.8 g/g) and lactic acid productivity (0.61 g/(l/h)) were obtained with an initial reducing sugar concentration of 35 g/l at 30°C when using Lactobacillus casei (10% inoculum) for a 42 h fermentation period. Thus, the experimental results demonstrated the feasibility of using a soybean straw enzymatic hydrolysate as a substrate for lactic acid production.

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

    Science.gov (United States)

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

    2008-02-01

    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 × 1015 ions/cm2. 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°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.

  14. Production of optically pure D-lactic acid from brown rice using metabolically engineered Lactobacillus plantarum.

    Science.gov (United States)

    Okano, Kenji; Hama, Shinji; Kihara, Maki; Noda, Hideo; Tanaka, Tsutomu; Kondo, Akihiko

    2017-03-01

    Simultaneous saccharification and fermentation (SSF) of D-lactic acid was performed using brown rice as both a substrate and a nutrient source. An engineered Lactobacillus plantarum NCIMB 8826 strain, in which the ʟ-lactate dehydrogenase gene was disrupted, produced 97.7 g/L D-lactic acid from 20% (w/v) brown rice without any nutrient supplementation. However, a significant amount of glucose remained unconsumed and the yield of lactic acid was as low as 0.75 (g/g-glucose contained in brown rice). Interestingly, the glucose consumption was significantly improved by adapting L. plantarum cells to the low-pH condition during the early stage of SSF (8-17 h). As a result, 117.1 g/L D-lactic acid was produced with a high yield of 0.93 and an optical purity of 99.6% after 144 h of fermentation. SSF experiments were repeatedly performed for ten times and D-lactic acid was stably produced using recycled cells (118.4-129.8 g/L). On average, D-lactic acid was produced with a volumetric productivity of 2.18 g/L/h over 48 h.

  15. Opportunities to overcome the current limitations and challenges for efficient microbial production of optically pure lactic acid.

    Science.gov (United States)

    Abdel-Rahman, Mohamed Ali; Sonomoto, Kenji

    2016-10-20

    There has been growing interest in the microbial production of optically pure lactic acid due to the increased demand for lactic acid-derived environmentally friendly products, for example biodegradable plastic (poly-lactic acid), as an alternative to petroleum-derived materials. To maximize the market uptake of these products, their cost should be competitive and this could be achieved by decreasing the production cost of the raw material, that is, lactic acid. It is of great importance to isolate and develop robust and highly efficient microbial lactic acid producers. Alongside the fermentative substrate and concentration, the yield and productivity of lactic acid are key parameters and major factors in determining the final production cost of lactic acid. In this review, we will discuss the current limitations and challenges for cost-efficient microbial production of optically pure lactic acid. The main obstacles to effective fermentation are the use of food resources, indirect utilization of polymeric sugars, sensitivity to inhibitory compounds released during biomass treatments, substrate inhibition, decreased lactic acid yield and productivity, inefficient utilization of mixed sugars, end product inhibition, increased use of neutralizing agents, contamination problems, and decreased optical purity of lactic acid. Furthermore, opportunities to address and overcome these limitations, either by fermentation technology or metabolic engineering approaches, will be introduced and discussed.

  16. Poly (lactic acid organoclay nano composites for paper coating applications

    Directory of Open Access Journals (Sweden)

    Tatcha Sonjui

    2014-10-01

    Full Text Available Poly(lactic acid or PLA is a well-known biodegradable polymer derived from renewable resources such as corn strach, tapioca strach, and sugar cane. PLA is the most extensively utilized biodegradable polyester with potential to replace conventional petrochemical-based polymers. However, PLA has some drawbacks, such as brittleness and poor gas barrier properties. Nano composite polymers have experience and increasing interest due to their characteristics, especially in mechanical and thermal properties. The objectives of this research were to prepare PLA formulations using three different PLAs. The formulas giving high gloss coating film were selected to prepare nano composite film by incorporated with different amount of various types of organoclays. The physical properties of the PLA coating films were studied and it was found that the PLA 7000D with 0.1%w/w of Cloisite 30B provided decent viscosity for coating process. In addition, the nano composite coating films showed good physical properties such as high gloss, good adhesion, and good hardness. There is a possibility of using the obtained formulation as a paper coating film.

  17. Properties of wheat gluten/poly(lactic acid) laminates.

    Science.gov (United States)

    Cho, Sung-Woo; Gällstedt, Mikael; Hedenqvist, Mikael S

    2010-06-23

    Laminates of compression-molded glycerol-plasticized wheat gluten (WG) films surrounded and supported by poly(lactic acid) (PLA) films have been produced and characterized. The objective was to obtain a fully renewable high gas barrier film with sufficient mechanical integrity to function in, for example, extrusion-coating paper/board applications. It was shown that the lamination made it possible to make films with a broad range of glycerol contents (0-30 wt %) with greater strength than single unsupported WG films. The low plasticizer contents yielded laminates with very good oxygen barrier properties. In addition, whereas the unsupported WG films had an immeasurably high water vapor transmission rate (WVTR), the laminate showed values that were finite and surprisingly, in several cases, also lower than that of PLA. Besides being a mechanical support (as evidenced by bending and tensile data) and a shield between the WG and surrounding moisture, the PLA layer also prevented the loss of the glycerol plasticizer from the WG layer. This was observed after the laminate had been aged on an "absorbing" blotting paper for up to 17 weeks. The interlayer adhesion (peel strength) decreased with decreasing glycerol content and increasing WG film molding temperature (130 degrees C instead of 110 degrees C). The latter effect was probably due to a higher protein aggregation, as revealed by infrared spectroscopy. The lamination temperature (110-140 degrees C) did not, however, have a major effect on the final peel strength.

  18. Isolation and characterisation of lactic acid bacteria from donkey milk.

    Science.gov (United States)

    Soto Del Rio, Maria de Los Dolores; Andrighetto, Christian; Dalmasso, Alessandra; Lombardi, Angiolella; Civera, Tiziana; Bottero, Maria Teresa

    2016-08-01

    During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk.

  19. Biogenic amine production by lactic acid bacteria isolated from cider.

    Science.gov (United States)

    Garai, G; Dueñas, M T; Irastorza, A; Moreno-Arribas, M V

    2007-11-01

    To study the occurrence of histidine, tyrosine and ornithine decarboxylase activity in lactic acid bacteria (LAB) isolated from natural ciders and to examine their potential to produce detrimental levels of biogenic amines. The presence of biogenic amines in a decarboxylase synthetic broth and in cider was determined by reversed-phase high-performance liquid chromatography (RP-HPLC). Among the 54 LAB strains tested, six (five lactobacilli and one oenococci) were biogenic amine producers in both media. Histamine and tyramine were the amines formed by the LAB strains investigated. Lactobacillus diolivorans were the most intensive histamine producers. This species together with Lactobacillus collinoides and Oenococcus oeni also seemed to produce tyramine. No ability to form histamine, tyramine or putrescine by Pediococus parvulus was observed, although it is a known biogenic amine producer in wines and beers. This study demonstrated that LAB microbiota growing in ciders had the ability to produce biogenic amines, particularly histamine and tyramine, and suggests that this capability might be strain-dependent rather than being related to a particular bacterial species. Production of biogenic amines by food micro-organisms has continued to be the focus of intensive study because of their potential toxicity. The main goal was to identify the microbial species capable of producing these compounds in order to control their presence and metabolic activity in foods.

  20. Effect of Lactic Acid Bacterial Inoculants on Rice Straw Silage

    Institute of Scientific and Technical Information of China (English)

    HUA Jinling; ZHANG Yonggen; MEN Yuxin

    2008-01-01

    The trail was designed to study on technique aspects of ensiling rice straw (RS) appended amounts of lactobacillus.There were two groups according to silage ways, baled silage (BS) and chopped silage (CS), in which lactobacillus was added at levels of 10,15 and 20 mg·kg-1,respectively and the mixtures were placed into a packed polyethylene bags and stored at room temperature for 45 days.The results showed that lactobacillus had remarkable effect on fermentation characteristics of RS. The quality of the silage was improved with the lactobacillus addition.In the experiment the optimal quality of rice straw silage (RSS) can be obtained when lactobacillus was added with 15 or 20 mg·kg-1 level.The effect of different silage methods was very remarkable to the silage quality of same material.The quality of CS was better than that of long silage, at the same time,BS was feasible on condition of eligible level of lactic acid bacteria.

  1. Removal of Paralytic Shellfish Toxins by Probiotic Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Mari Vasama

    2014-07-01

    Full Text Available Paralytic shellfish toxins (PSTs are non-protein neurotoxins produced by saltwater dinoflagellates and freshwater cyanobacteria. The ability of Lactobacillus rhamnosus strains GG and LC-705 (in viable and non-viable forms to remove PSTs (saxitoxin (STX, neosaxitoxin (neoSTX, gonyautoxins 2 and 3 (GTX2/3, C-toxins 1 and 2 (C1/2 from neutral and acidic solution (pH 7.3 and 2 was examined using HPLC. Binding decreased in the order of STX ~ neoSTX > C2 > GTX3 > GTX2 > C1. Removal of STX and neoSTX (77%–97.2% was significantly greater than removal of GTX3 and C2 (33.3%–49.7%. There were no significant differences in toxin removal capacity between viable and non-viable forms of lactobacilli, which suggested that binding rather than metabolism is the mechanism of the removal of toxins. In general, binding was not affected by the presence of other organic molecules in solution. Importantly, this is the first study to demonstrate the ability of specific probiotic lactic bacteria to remove PSTs, particularly the most toxic PST-STX, from solution. Further, these results warrant thorough screening and assessment of safe and beneficial microbes for their usefulness in the seafood and water industries and their effectiveness in vivo.

  2. Use of inoculated lactic acid bacteria in fermenting sour cabbage

    Directory of Open Access Journals (Sweden)

    E. PETÄJÄ

    2008-12-01

    Full Text Available Fermentation of sour vegetables has to date occurred through the use of lactic acid bacteria (LAB naturally present in vegetables. The present article deals with preliminary studies on the effects of some LAB inocula (Lactobacillus alimentarius or Pediococcus pentosaceus on fermenting sour cabbage. The effect of LAB on yeast growth, a problem in sour vegetables, was also studied through the use of dual yeast and LAB inocula. The pH of cabbage juice decreased to levels under pH 4 during the first 10 days of fermentation, which is near the final values, pediococci decreasing the pH to the lowest values. The LAB count in inoculated cabbages increased by 0.5-2.0 log cfu (colony forming unit /g during the first 10 days of fermentation and thereafter decreased. Pediococci formed predominant part of microbial flora almost in all experimental batches. In cabbage challenged with yeasts, yeast counts rose only when the pH was < 3.5. Yeasts appeared almost regularly also in cabbages inoculated only with LAB. Pediococci fermented cabbage effectively decreasing the pH to lower levels than lactobacilli or natural LAB. However, too strong a decrease in pH may result in a decrease of LAB count which may subsequently lead to yeast growth. The yeast problem could not be solved with the LAB inocula used in our study.;

  3. Fracture behavior of quenched poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2011-01-01

    Full Text Available The effect of a quenching treatment applied on heated cast sheet extruded films of two poly(lactic acid (PLA commercial grades, with different optical purities, was studied. The thermal and mechanical properties of the films, as well as their fracture behavior, were assessed by differential scanning calorimetry (DSC, tensile tests, and the essential work of fracture (EWF approach. The heating-quenching treatment causes a de-aging effect with an increase in the free volume of polymer chains evidenced by a decrease in the glass transition temperature (Tg and a decrease in the tensile stiffness and yield stress. As a result, there is an abrupt increase in ductility, finding a dramatic change in the fracture behavior, from brittle to ductile. The use of digital image correlation (DIC of the strain field analysis during fracture testing has allowed relating the decrease on the yield stress promoted by quenching with the crack propagation kinetics. The use of the EWF method to characterize the fracture toughness of PLA has allowed to measure this enhancement on toughness, finding that the specific essential work of fracture (we and the plastic term (βwp parameters increased 120% and 1200%, respectively, after the quenching process.

  4. CHARACTERIZATION OF LACTIC ACID BACTERIA ISOLATED FROM SUMBAWA MARE MILK

    Directory of Open Access Journals (Sweden)

    Nengah Sujaya

    2008-06-01

    Full Text Available A study was carried out to isolate and characterize lactic acid bacteria (LAB from the Sumbawa mares milk The Isolation of LAB was conducted in Man Rogosa Sharpe (MRS agar. The isolates were characterized by standard methods, such as Gram staining, cell morphology study and fermentation activities. The ability of the isolates to inhibit some pathogenic bacteria was studied by dual culture assay. Isolates showing the widest spectrum of inhibiting pathogenic bacteria were further identified using API 50 CHL. The results showed that Sumbawa mare milk was dominated by lactobacilli and weisella/leuconostoc. As many as 26 out 36 isolates belong to homofermentative lactobacilli and another 10 isolates belong to both heterofermentative lactobacilli and weissella or leuconostoc. Twenty four isolates inhibited the growth of Escherichia coli 25922, Shigela flexneri, Salmonella typhimurium, and Staphylococcus aureus 29213. Two promising isolates with the widest spectrum of inhibiting pathogenic bacteria, Lactobacillus sp. SKG34 and Lactobacillus sp. SKG49, were identified respectively as Lactobacillus rhamnosus SKG34 and Lactobacillus ramnosus SKG49. These two isolates were specific strains of the sumbawa mare milk and are very potential to be developed as probiotic for human.

  5. Screening of oxalate degrading lactic acid bacteria of food origin

    Directory of Open Access Journals (Sweden)

    Nicoletta Murru

    2017-04-01

    Full Text Available A screening for oxalate degrading abilities was initially carried on within Lactic Acid Bacteria cultures of different food origin. Seventy-nine strains were drop-inoculated onto MRS agar plates containing calcium oxalate. By comparing colonies diameters, 31 strains were used to inoculate, in parallel, MRS and MRS modified by sodium oxalate addition. Differences in the strains’ growth were assessed by colony forming unit counts. For two strains, the growth in oxalate enriched medium was significantly higher; while, for eleven strains an opposite behaviour was recorded. Two strains – probiotic Lactobacillus rhamnosus LbGG and Enterococcus faecalis 59 – were chosen. The first strain appeared to be able to metabolize oxalate more efficiently than the other tested cultures, while strain 59 appeared unable to gather advantage by oxalates and, indeed, appeared to be inhibited by the salt presence in the medium. Outcomes revealed that higher glucose concentrations may favour oxalates utilization. In MRS with oxalate, but without glucose, citrate was completely metabolized. Evaluation along time confirmed that the oxalate degradation is more significant in presence of glucose. Outcomes may represent a good start for the development of a safe and even probiotic culture able to lower the oxalates content of food.

  6. Optimization of β-galactosidase production from lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    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.

  7. Lactic acid bacteria in dried vegetables and spices.

    Science.gov (United States)

    Säde, Elina; Lassila, Elisa; Björkroth, Johanna

    2016-02-01

    Spices and dried vegetable seasonings are potential sources of bacterial contamination for foods. However, little is known about lactic acid bacteria (LAB) in spices and dried vegetables, even though certain LAB may cause food spoilage. In this study, we enumerated LAB in 104 spices and dried vegetables products aimed for the food manufacturing industry. The products were obtained from a spice wholesaler operating in Finland, and were sampled during a one-year period. We picked isolates (n = 343) for species identification based on numerical analysis of their ribotyping patterns and comparing them with the corresponding patterns of LAB type strains. We found LAB at levels >2 log CFU/g in 68 (65%) of the samples, with the highest counts detected from dried onion products and garlic powder with counts ranging from 4.24 to 6.64 log CFU/g. The LAB identified were predominantly Weissella spp. (61%) and Pediococcus spp. (15%) with Weissella confusa, Weissella cibaria, Weissella paramesenteroides, Pediococcus acidilactici and Pediococcus pentosaceus being the species identified. Other species identified belonged to the genera of Enterococcus spp. (8%), Leuconostoc spp. (6%) and Lactobacillus spp. (2%). Among the LAB identified, Leuconostoc citreum, Leuconostoc mesenteroides and W. confusa have been associated with food spoilage. Our findings suggest that spices and dried vegetables are potential sources of LAB contamination in the food industry.

  8. Genome level analysis of bacteriocins of lactic acid bacteria.

    Science.gov (United States)

    Singh, Neetigyata Pratap; Tiwari, Abhay; Bansal, Ankiti; Thakur, Shruti; Sharma, Garima; Gabrani, Reema

    2015-06-01

    Bacteriocins are antimicrobial peptides which are ribosomally synthesized by mainly all bacterial species. LABs (lactic acid bacteria) are a diverse group of bacteria that include around 20 genera of various species. Though LABs have a tremendous potential for production of anti-microbial peptides, this group of bacteria is still underexplored for bacteriocins. To study the diversity among bacteriocin encoding clusters and the putative bacteriocin precursors, genome mining was performed on 20 different species of LAB not reported to be bacteriocin producers. The phylogenetic tree of gyrB, rpoB, and 16S rRNA were constructed using MEGA6 software to analyze the diversity among strains. Putative bacteriocins operons identified were found to be diverse and were further characterized on the basis of physiochemical properties and the secondary structure. The presence of at least two cysteine residues in most of the observed putative bacteriocins leads to disulphide bond formation and provide stability. Our data suggests that LABs are prolific source of low molecular weight non modified peptides.

  9. A gene network engineering platform for lactic acid bacteria.

    Science.gov (United States)

    Kong, Wentao; Kapuganti, Venkata S; Lu, Ting

    2016-02-29

    Recent developments in synthetic biology have positioned lactic acid bacteria (LAB) as a major class of cellular chassis for applications. To achieve the full potential of LAB, one fundamental prerequisite is the capacity for rapid engineering of complex gene networks, such as natural biosynthetic pathways and multicomponent synthetic circuits, into which cellular functions are encoded. Here, we present a synthetic biology platform for rapid construction and optimization of large-scale gene networks in LAB. The platform involves a copy-controlled shuttle for hosting target networks and two associated strategies that enable efficient genetic editing and phenotypic validation. By using a nisin biosynthesis pathway and its variants as examples, we demonstrated multiplex, continuous editing of small DNA parts, such as ribosome-binding sites, as well as efficient manipulation of large building blocks such as genes and operons. To showcase the platform, we applied it to expand the phenotypic diversity of the nisin pathway by quickly generating a library of 63 pathway variants. We further demonstrated its utility by altering the regulatory topology of the nisin pathway for constitutive bacteriocin biosynthesis. This work demonstrates the feasibility of rapid and advanced engineering of gene networks in LAB, fostering their applications in biomedicine and other areas.

  10. Bioconversion of oleuropein to hydroxytyrosol by lactic acid bacteria.

    Science.gov (United States)

    Santos, M M; Piccirillo, C; Castro, P M L; Kalogerakis, N; Pintado, M E

    2012-06-01

    The aim of this work is to study the conversion of oleuropein-a polyphenol present in olives and olive oil by-products-into hydroxytyrosol, a polyphenol with antioxidant and antibacterial properties. The hydrolysis reaction is performed by lactic acid bacteria. Six bacterial strains (Lactobacillus plantarum 6907, Lactobacillus paracasei 9192, Lactobacillus casei, Bifidobacterium lactis BO, Enterococcus faecium 32, Lactobacillus LAFTI 10) were tested under aerobic and anaerobic conditions. The oleuropein degradation and hydroxytyrosol formation were monitored by HPLC. Results showed that oleuropein could be successfully converted into hydroxytyrosol. The most effective strain was Lactobacillus plantarum 6907, with a reaction yield of hydroxytyrosol of about 30 %. Different reaction mechanisms were observed for different microorganisms; a different yield was observed for Lactobacillus paracasei 9192 under aerobic or anaerobic conditions and an intermediate metabolite (oleuropein aglycone) was detected for Lactobacillus paracasei 9192 and Lactobacillus plantarum 6907 only. This study could have significant applications, as this reaction can be used to increase the value of olive oil by-products and/or to improve the taste of unripe olives.

  11. Enhanced crystallization of poly (lactic acid) through reactive aliphatic bisamide

    Science.gov (United States)

    Nanthananon, P.; Seadan, M.; Pivsa-Art, S.; Suttiruengwong, S.

    2015-07-01

    The poor crystallization rate of poly (lactic acid) (PLA) is a major drawback in terms of controlling the properties of final products. To overcome this, a nucleating agent is normally applied. In this work, the aliphatic bisamide, N, N'-(1,3-propylene) bis(10-undecenamide) (PBU), having reactive functional groups is used as a crystallization promoter for PLA by adding PBU in various concentration (0.1-0.7 wt%) into PLA together with peroxide via reactive melt blending. The conventional ethylene bis-stearamide(EBS) is used for a comparison. The extruded samples are characterized for gel content and FT-IR spectroscopy. The crystallization behaviour and rate, and spherulites morphology are investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. It is found that the addition of PBU into PLA results in the dramatic increase in crystallinity and crystallization rate of PLA compared with neat PLA and PLA added EBS. The crystallinity increases to 24.9-28.3% higher than neat PLA under even cooling rate of 7°C/min. The addition of 0.7 wt% PBU shows the fastest crystallization rate with t1/2 value isothermally crystallized at 130°C of only 6 min. POM images indicate the increase in the nucleation density and very fine spherulitesof PLA added PBU, promoting the fast crystallization.

  12. Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

    Directory of Open Access Journals (Sweden)

    Keita Nishiyama

    2016-09-01

    Full Text Available Lactic acid bacteria (LAB are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective.

  13. Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

    Science.gov (United States)

    Nishiyama, Keita; Sugiyama, Makoto; Mukai, Takao

    2016-01-01

    Lactic acid bacteria (LAB) are Gram-positive bacteria that are natural inhabitants of the gastrointestinal (GI) tracts of mammals, including humans. Since Mechnikov first proposed that yogurt could prevent intestinal putrefaction and aging, the beneficial effects of LAB have been widely demonstrated. The region between the duodenum and the terminal of the ileum is the primary region colonized by LAB, particularly the Lactobacillus species, and this region is covered by a mucus layer composed mainly of mucin-type glycoproteins. The mucus layer plays a role in protecting the intestinal epithelial cells against damage, but is also considered to be critical for the adhesion of Lactobacillus in the GI tract. Consequently, the adhesion exhibited by lactobacilli on mucin has attracted attention as one of the critical factors contributing to the persistent beneficial effects of Lactobacillus in a constantly changing intestinal environment. Thus, understanding the interactions between Lactobacillus and mucin is crucial for elucidating the survival strategies of LAB in the GI tract. This review highlights the properties of the interactions between Lactobacillus and mucin, while concomitantly considering the structure of the GI tract from a histochemical perspective. PMID:27681930

  14. Poly(lactic acid) blends in biomedical applications.

    Science.gov (United States)

    Saini, P; Arora, M; Kumar, M N V Ravi

    2016-12-15

    Poly(lactic acid) (PLA) has become a "material of choice" in biomedical applications for its ability to fulfill complex needs that typically include properties such as biocompatibility, biodegradability, mechanical strength, and processability. Despite the advantages of pure PLA in a wider spectrum of applications, it is limited by its hydrophobicity, low impact toughness, and slow degradation rate. Blending PLA with other polymers offers a convenient option to enhance its properties or generate novel properties for target applications without the need to develop new materials. PLA blends with different natural and synthetic polymers have been developed by solvent and melt blending techniques and further processed based on end-use applications. A variety of PLA blends has been explored for biomedical applications such as drug delivery, implants, sutures, and tissue engineering. This review discusses the opportunities for PLA blends in the biomedical arena, including the overview of blending and postblend processing techniques and the applications of PLA blends currently in use and under development. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Pretreatment of corn stover by solid acid for d-lactic acid fermentation.

    Science.gov (United States)

    Wang, Xiqing; Wang, Gang; Yu, Xiaoxiao; Chen, Huan; Sun, Yang; Chen, Guang

    2017-09-01

    Solid acid is a new acid that is safe and green, which has been widely used in the fields of acid pickling. In this study, we adopted solid acid to pretreat corn stover and used the pretreated corn stover in the fermentation of d-lactic acid. Finally, we obtained optimal conditions for the pretreatment of corn stover by solid acid: digestion temperature of 120°C, digestion time of 80min, and solid acid concentration of 1.5%. Then adding cellulase of 30FPU/g, the conversion rate of glucose reached 71.06% after enzymatic hydrolysis for 72h. In addition, the changes of corn stover structure after pretreatment were further represented by using scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). At the same time, we used the pretreated corn stover as fermentation substrate and Lactobacillus. delbrueckii sp. bulgaricus as the starting strain to produce d-lactic acid. The yield reached 18g/L, with the optical purity being 99%e.e. This research has provided a new way to comprehensively utilizae corn stover. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Impacts of lignocellulose-derived inhibitors on L-lactic acid fermentation by Rhizopus oryzae.

    Science.gov (United States)

    Zhang, Li; Li, Xin; Yong, Qiang; Yang, Shang-Tian; Ouyang, Jia; Yu, Shiyuan

    2016-03-01

    Inhibitors generated in the pretreatment and hydrolysis of corn stover and corn cob were identified. In general, they inhibited cell growth, lactate dehydrogenase, and lactic acid production but with less or no adverse effect on alcohol dehydrogenase and ethanol production in batch fermentation by Rhizopus oryzae. Furfural and 5-hydroxymethyl furfural (HMF) were highly toxic at 0.5-1 g L(-1), while formic and acetic acids at less than 4 g L(-1) and levulinic acid at 10 g L(-1) were not toxic. Among the phenolic compounds at 1 g L(-1), trans-cinnamic acid and syringaldehyde had the highest toxicity while syringic, ferulic and p-coumaric acids were not toxic. Although these inhibitors were present at concentrations much lower than their separately identified toxic levels, lactic acid fermentation with the hydrolysates showed much inferior performance compared to the control without inhibitor, suggesting synergistic or compounded effects of the lignocellulose-degraded compounds on inhibiting lactic acid fermentation.

  17. THE SEARCH AND PROPERTIES OF LACTIC ACID BACTERIA PERSPECTIVE FOR BIOTECHNOLOGY

    Directory of Open Access Journals (Sweden)

    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.

  18. Mosquito larvicidal effect of orthophosporic acid and lactic acid individually or their combined form on Aedes aegypti

    Institute of Scientific and Technical Information of China (English)

    Supratik Chakraborty; Someshwar Singha; Goutam Chandra

    2010-01-01

    Objective: To observe the effect of two common organic acids on the larvae of Aedes aegypti (Ae. aegypti) (L), the natural vector of dengue fever/dengue hemorrhage fever, chikugunya and allergic skin reaction especially in children. Methods: Two common organic acids (lactic acid and orthophosporic acid of gradually increasing concentration) were used against laboratory reared third instars larvae of Ae. aegypti in order to observe the rate of mortality after 8, 16 and 24 h of post exposure respectively in laboratory. Results: Larval mortality rates recorded were in the following sequences: orthophosphoric acid and lactic acid at 1:1 combination >orthophosphoric acid>lactic acid. Conclusions: These two organic acids may be used perfectly in combination (1:1) along with other conventional vector control methods to reduce the Ae. aegypti population, especially in those areas where surveillance and supervisory mechanism are poor or insufficient.

  19. Simultaneous saccharification and high titer lactic acid fermentation of corn stover using a newly isolated lactic acid bacterium Pediococcus acidilactici DQ2.

    Science.gov (United States)

    Zhao, Kai; Qiao, Qingan; Chu, Deqiang; Gu, Hanqi; Dao, Thai Ha; Zhang, Jian; Bao, Jie

    2013-05-01

    A lactic acid bacterium with high tolerance of temperature and lignocellulose derived inhibitor was isolated and characterized as Pediococcus acidilactici DQ2. The strain used in the simultaneous saccharification and fermentation (SSF) for high titer lactic acid production at the high solids loading of corn stover. Corn stover was pretreated using the dry sulphuric acid pretreatment, followed by a biological detoxification to remove the inhibitors produced in the pretreatment. The bioreactor with a novel helical impeller was used to the SSF operation of the pretreated and biodetoxified corn stover. The results show that a typical SSF operation at 48 °C, pH 5.5, and near 30% (w/w) solids loading in both 5 and 50 L bioreactors was demonstrated. The lactic acid titer, yield, and productivity reached 101.9 g/L, 77.2%, and 1.06 g/L/h, respectively. The result provided a practical process option for cellulosic lactic acid production using virgin agriculture lignocellulose residues.

  20. Lactic acid delays the inflammatory response of human monocytes.

    Science.gov (United States)

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

    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. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Electrospun poly(lactic acid) based conducting nanofibrous networks

    Energy Technology Data Exchange (ETDEWEB)

    Patra, S N; Bhattacharyya, D [Department of Mechanical Engineering, Centre for Advanced Composite Materials, University of Auckland, Private Bag 92019, Auckland (New Zealand); Ray, S; Easteal, A J, E-mail: d.bhattacharyya@auckland.ac.nz [Department of Chemistry, Centre for Advanced Composite Materials, University of Auckland, Private Bag 92019, Auckland (New Zealand)

    2009-08-15

    Multi-functionalised micro/nanostructures of conducting polymers in neat or blended forms have received much attention because of their unique properties and technological applications in electrical, magnetic and biomedical devices. Biopolymer-based conducting fibrous mats are of special interest for tissue engineering because they not only physically support tissue growth but also are electrically conductive, and thus are able to stimulate specific cell functions or trigger cell responses. They are effective for carrying current in biological environments and can thus be considered for delivering local electrical stimuli at the site of damaged tissue to promote wound healing. Electrospinning is an established way to process polymer solutions or melts into continuous fibres with diameter often in the nanometre range. This process primarily depends on a number of parameters, including the type of polymer, solution viscosity, polarity and surface tension of the solvent, electric field strength and the distance between the spinneret and the collector. The present research has included polyaniline (PANi) as the conducting polymer and poly(L-lactic acid) (PLLA) as the biopolymer. Dodecylbenzene sulphonic acid (DBSA) doped PANi and PLLA have been dissolved in a common solvent (mixtures of chloroform and dimethyl formamide (DMF)), and the solutions successfully electrospun. DMF enhanced the dielectric constant of the solvent, and tetra butyl ammonium bromide (TBAB) was used as an additive to increase the conductivity of the solution. DBSA-doped PANi/PLLA mat exhibits an almost bead-free network of nanofibres that have extraordinarily smooth surface and diameters in the range 75 to 100 nm.

  2. Electrospun poly(lactic acid) based conducting nanofibrous networks

    Science.gov (United States)

    Patra, S. N.; Bhattacharyya, D.; Ray, S.; Easteal, A. J.

    2009-08-01

    Multi-functionalised micro/nanostructures of conducting polymers in neat or blended forms have received much attention because of their unique properties and technological applications in electrical, magnetic and biomedical devices. Biopolymer-based conducting fibrous mats are of special interest for tissue engineering because they not only physically support tissue growth but also are electrically conductive, and thus are able to stimulate specific cell functions or trigger cell responses. They are effective for carrying current in biological environments and can thus be considered for delivering local electrical stimuli at the site of damaged tissue to promote wound healing. Electrospinning is an established way to process polymer solutions or melts into continuous fibres with diameter often in the nanometre range. This process primarily depends on a number of parameters, including the type of polymer, solution viscosity, polarity and surface tension of the solvent, electric field strength and the distance between the spinneret and the collector. The present research has included polyaniline (PANi) as the conducting polymer and poly(L-lactic acid) (PLLA) as the biopolymer. Dodecylbenzene sulphonic acid (DBSA) doped PANi and PLLA have been dissolved in a common solvent (mixtures of chloroform and dimethyl formamide (DMF)), and the solutions successfully electrospun. DMF enhanced the dielectric constant of the solvent, and tetra butyl ammonium bromide (TBAB) was used as an additive to increase the conductivity of the solution. DBSA-doped PANi/PLLA mat exhibits an almost bead-free network of nanofibres that have extraordinarily smooth surface and diameters in the range 75 to 100 nm.

  3. Lactic acid production from wheat straw hemicellulose hydrolysate by Lactobacillus pentosus and Lactobacillus brevis

    DEFF Research Database (Denmark)

    Garde, Arvid; Jonsson, Gunnar Eigil; Schmidt, A. S.

    2002-01-01

    Lactic acid production by Lactobacillus brevis and Lactobacillus pentosus on a hemicellulose hydrolysate (HH) of wet-oxidized wheat straw was evaluated. The potential of 11-12 g/l fermentable sugars was released from the HH through either enzymatic or acidic pretreatment. Fermentation of added...... xylose in untreated HH after wet-oxidation, showed no inhibition on the lactic acid production by either Lb. pentosus or Lb. brevis. Lb. pentosus produced lactate corresponding to 88% of the theoretical maximum yield regardless of the hydrolysis method, whereas Lb. brevis produced 51% and 61......% of the theoretical maximum yield after enzymatic, or acid treatment of HH, respectively. Individually, neither of the two strains were able to fully utilize the relatively broad spectra of sugars released by the acid and enzyme treatments; however, lactic acid production increased to 95% of the theoretical maximum...

  4. Activity of virgin coconut oil, lauric acid or monolaurin in combination with lactic acid against Staphylococcus aureus.

    Science.gov (United States)

    Tangwatcharin, Pussadee; Khopaibool, Prapaporn

    2012-07-01

    The objective of this study was to investigate the in vitro activities of virgin coconut oil, lauric acid and monolaurin in combination with lactic acid against two strains of Staphylococcus aureus, ATCC 25923 and an isolate from a pig carcass, by determination of Fractional Bactericidal Concentration Index (FBCI), time-kill method, as well as scanning and transmission electron microscopy. Minimum bactericidal concentrations (MBC) of lauric acid, monolaurin and lactic acid were 3.2 mg/ml, 0.1 mg/ml and 0.4% (v/v), respectively. The effects of lauric acid + lactic acid and monolaurin + lactic acid combinations were synergistic against both strains, exhibiting FBCIs of 0.25 and 0.63, respectively. In time-kill studies, lauric acid and monolaurin + lactic acid combinations added at their minimum inhibitory concentrations produced a bactericidal effect. The induction of stress in non-stressed cells was dependent on the type and concentration of antimicrobial. This resulted in a loss and change of the cytoplasm and membrane in cells of the bacterium. In contrast, virgin coconut oil (10%) was not active against S. aureus. The bacterial counts found in pork loin treated with lauric acid and monolaurin alone were significantly higher (p <0.05) than those treated with both lipids in combination with lactic acid at sub-inhibitory concentrations. The color, odor and overall acceptability of the pork loins were adversely affected by treatment with the three lipids and lactic acid alone but when combinations of the agents were used the sensory quality was acceptable.

  5. Randomized clinical efficacy of superficial peeling with 85% lactic acid versus 70% glycolic acid*

    Science.gov (United States)

    Prestes, Paula Souza; de Oliveira, Márcia Motta Maia; Leonardi, Gislaine Ricci

    2013-01-01

    BACKGROUND: Peeling is a procedure which aims to accelerate the process of skin exfoliation. OBJECTIVES Development of formulations containing lactic acid at 85% or glycolic acid at 70% and the evaluation of these formulations on clinical efficacy in reduction of fine wrinkles. METHODS Preliminary stability tests were carried out and an in vivo study was performed with three groups with 9 representatives each. One was the control group, which used only sunscreen; another one used lactic acid+sunscreen, and the last group used acid glycolic+sunscreen. Clinical efficacy was assessed with a CCD color microscope, through the digitization of images before and after treatment. The applications were carried out by a dermatologist, once a mont h every 30 days, during 3 months. The area with wrinkles was calculated by planimetry point counting, in accordance with Mandarin-de-Lacerda. RESULTS The formulations were stable in the visual and Ph evaluation. There was no improvement in the control group; for lactic acid, there was significant improvement after the second peeling application on the outer lateral area of the right eye and after the third application on the outer lateral area of the left eye. For the glycolic acid group, there was significant improvement in the outer lateral area of the left eye after the first application, and of the right eye region, after three applications. The formulations used must be kept under refrigeration and should be manipulated every 30 days. CONCLUSIONS Both peelings were effective in reducing fine wrinkles of the outer lateral eye area after three applications (p≤0.05%). It was observed that peeling efficacy in the external-lateral region of one eye might be different compared with that in skin of the external-lateral region of the other eye, relative to the speed of skin improvement. PMID:24474097

  6. Randomized clinical efficacy of superficial peeling with 85% lactic acid versus 70% glycolic acid.

    Science.gov (United States)

    Prestes, Paula Souza; Oliveira, Márcia Motta Maia de; Leonardi, Gislaine Ricci

    2013-01-01

    Peeling is a procedure which aims to accelerate the process of skin exfoliation. Development of formulations containing lactic acid at 85% or glycolic acid at 70% and the evaluation of these formulations on clinical efficacy in reduction of fine wrinkles. Preliminary stability tests were carried out and an in vivo study was performed with three groups with 9 representatives each. One was the control group, which used only sunscreen; another one used lactic acid+sunscreen, and the last group used acid glycolic+sunscreen. Clinical efficacy was assessed with a CCD color microscope, through the digitization of images before and after treatment. The applications were carried out by a dermatologist, once a mont h every 30 days, during 3 months. The area with wrinkles was calculated by planimetry point counting, in accordance with Mandarin-de-Lacerda. The formulations were stable in the visual and Ph evaluation. There was no improvement in the control group; for lactic acid, there was significant improvement after the second peeling application on the outer lateral area of the right eye and after the third application on the outer lateral area of the left eye. For the glycolic acid group, there was significant improvement in the outer lateral area of the left eye after the first application, and of the right eye region, after three applications. The formulations used must be kept under refrigeration and should be manipulated every 30 days. Both peelings were effective in reducing fine wrinkles of the outer lateral eye area after three applications (p ≤ 0.05%). It was observed that peeling efficacy in the external-lateral region of one eye might be different compared with that in skin of the external-lateral region of the other eye, relative to the speed of skin improvement.

  7. Selective catalysis for cellulose conversion to lactic acid and other α-hydroxy acids.

    Science.gov (United States)

    Dusselier, Michiel; Sels, Bert F

    2014-01-01

    This review discusses topical chemical routes and their catalysis for the conversion of cellulose, hexoses, and smaller carbohydrates to lactic acid and other useful α-hydroxy acids. Lactic acid is a top chemical opportunity from carbohydrate biomass as it not only features tremendous potential as a chemical platform molecule; it is also a common building block for commercially employed green solvents and near-commodity bio-plastics. Its current scale fermentative synthesis is sufficient, but it could be considered a bottleneck for a million ton scale breakthrough. Alternative chemical routes are therefore investigated using multifunctional, often heterogeneous, catalysis. Rather than summarizing yields and conditions, this review attempts to guide the reader through the complex reaction networks encountered when synthetic lactates from carbohydrate biomass are targeted. Detailed inspection of the cascade of reactions emphasizes the need for a selective retro-aldol activity in the catalyst. Recently unveiled catalytic routes towards other promising α-hydroxy acids such as glycolic acid, and vinyl and furyl glycolic acids are highlighted as well.

  8. High-efficiency l-lactic acid production by Rhizopus oryzae using a novel modified one-step fermentation strategy.

    Science.gov (United States)

    Fu, Yong-Qian; Yin, Long-Fei; Zhu, Hua-Yue; Jiang, Ru

    2016-10-01

    In this study, lactic acid fermentation by Rhizopus oryzae was investigated using the two different fermentation strategies of one-step fermentation (OSF) and conventional fermentation (CF). Compared to CF, OSF reduced the demurrage of the production process and increased the production of lactic acid. However, the qp was significantly lower than during CF. Based on analysis of μ, qs and qp, a novel modified OSF strategy was proposed. This strategy aimed to achieve a high final concentration of lactic acid, and a high qp by R. oryzae. In this strategy, the maximum lactic acid concentration and productivity of the lactic acid production stage reached 158g/l and 5.45g/(lh), which were 177% and 366% higher, respectively, than the best results from CF. Importantly, the qp and yield did not decrease. This strategy is a convenient and economical method for l-lactic acid fermentation by R. oryzae.

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

    Science.gov (United States)

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

    2014-11-28

    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, pH7.4) and acetate buffer (AB, pH4.3), 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Effect of montmorillonite clay on flax fabric reinforced poly lactic acid composites with amphiphilic additives

    CSIR Research Space (South Africa)

    Kumar, R

    2010-01-01

    Full Text Available Bio-composites (PF) were successfully prepared by reinforcing poly lactic acid (PLA) with woven flax fibers (F) in the presence of mandelic acid, benzilic acid, dicumyl peroxide (DCP) and zein as dditives. To improve the mechanical properties...

  11. Unravelling the multiple effects of lactic acid stress on Lactobacillus plantarum by transcription profiling

    NARCIS (Netherlands)

    Pieterse, B.; Leer, R.J.; Schuren, F.H.J.; Werf, M.J. van der

    2005-01-01

    The organic acid lactate is the predominant fermentation product of Lactobacillus plantarum. The undissociated form of this organic acid is a strong growth inhibitor for the organism. Different theories have been postulated to explain the inhibitory effects of lactic acid: (i) toxicity arising from

  12. Short communication: Conversion of lactose and whey into lactic acid by engineered yeast.

    Science.gov (United States)

    Turner, Timothy L; Kim, Eunbee; Hwang, ChangHoon; Zhang, Guo-Chang; Liu, Jing-Jing; Jin, Yong-Su

    2017-01-01

    Lactose is often considered an unwanted and wasted byproduct, particularly lactose trapped in acid whey from yogurt production. But using specialized microbial fermentation, the surplus wasted acid whey could be converted into value-added chemicals. The baker's yeast Saccharomyces cerevisiae, which is commonly used for industrial fermentation, cannot natively ferment lactose. The present study describes how an engineered S. cerevisiae yeast was constructed to produce lactic acid from purified lactose, whey, or dairy milk. Lactic acid is an excellent proof-of-concept chemical to produce from lactose, because lactic acid has many food, pharmaceutical, and industrial uses, and over 250,000 t are produced for industrial use annually. To ferment the milk sugar lactose, a cellodextrin transporter (CDT-1, which also transports lactose) and a β-glucosidase (GH1-1, which also acts as a β-galactosidase) from Neurospora crassa were expressed in a S. cerevisiae strain. A heterologous lactate dehydrogenase (encoded by ldhA) from the fungus Rhizopus oryzae was integrated into the CDT-1/GH1-1-expressing strain of S. cerevisiae. As a result, the engineered strain was able to produce lactic acid from purified lactose, whey, and store-bought milk. A lactic acid yield of 0.358g/g of lactose was achieved from whey fermentation, providing an initial proof of concept for the production of value-added chemicals from excess industrial whey using engineered yeast. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Examination of Lactic Acid Bacteria to Secretion of Bacteriocins

    Directory of Open Access Journals (Sweden)

    Maira Urazova

    2014-01-01

    Full Text Available Introduction: Bacteriocins produced by lactic acid bacteria (LAB have the potential to cover a very broad field of applications, including the food industry and the medical sector. In the food industry, bacteriocinogenic LAB strains can be used as starter cultures, co-cultures, and bioprotective cultures, which would be used to improve food quality and safety. In the medical sector, bacteriocins of probiotic LAB might play a role in interactions, which take place in human gastrointestinal tract, and contribute to gut health. The aim of this study was the examine the effect of LAB antimicrobial activity. Methods: LAB were isolated from different commercial and home made products, such as kazy and sour cream. To screen for bacteriocin producing LAB, we used an agar diffusion bioassay, described in a previous study by Dr. Yang, with three modifications in cell-free supernatant (CFS. First we had a clear supernatant, second we adjusted the CFS to pH 6.0 to eliminate acids antimicrobial effects, and third the CFS pH 6.0 was treated with catalase to exclude the action of H2O2 and confirm action of bacteriocin-like substances. Pathogenic S.marcescens, E. coli, S.aureus cultures were used as indicators. Results: Screening of 95 strains of LAB through deferred antagonism to six indicator cultures showed that all of the selected strains had a high value of antibacterial activity. However, CFS of only 50 strains retained their antimicrobial activity, and 10 of them lost this activity in the second modification of CFS with pH 6.0 to test culture S.marcescens, which confirmed the acidic nature of antimicrobial activity of CFS. Lb.rhamnosus (P-1, Lb.fermentum (N-6, and Lc.lactis (7M lost antibacterial activity in the presence of the catalase. All modifications of CFS of three strains: Lb.pentosus (16al, Lb.pentosus (P-2, and Pediococcusacidilactici (8 retained inhibitory activity to E.coli and S. aureus. Supernatants of only Lactococcusgarvieae (10a and

  14. PROBIOTIC POTENTIALS AMONG LACTIC ACID BACTERIA ISOLATED FROM CURD

    Directory of Open Access Journals (Sweden)

    Shruthy VV

    2011-02-01

    Full Text Available Curd is a commonly used fermented milk product in India since time immemorial. The scientific use of curd as a source of probiotic (good bacteria for health has not been much examined. The yougurt (curd containing probiotics is in Indian market and highly acclaimed. Therefore the status of curd as a source of probiotics is in question and requires scientific examination of its content, so the study was carried out. Probiotic potentials of two bacterial isolates from 20 different curd samples were identified as Lactobacillus spp. by the determination of morphological, cultural, physiological and biochemical characteristics, were investigated. The antibacterial potential against diarrhoegenic bacterial pathogens was also examined. The reference strain used was Lactobacillus acidophilus, MTCC 447. The percentage survivability of the strains at pH 3.5, was found to be satisfactory (>90%. Bile salt resistance (0.3% sodium thioglycollate was found to be between 80.41% and 83.2%. The pH decrease of the strains with time showed slow acidification activity. The lactic acid production of the strains ranges from 1.83 ± 0.12 to 3.93 ± 0.07 g. The strains were β-galactosidase producer and were resistant to principal antibiotics tested. But the absence of plasmids showed that they are intrinsically resistant or chromosome encoded. Strains showed maximum inhibition zone against V. cholerae O139 (13.67 ± 0.57 to 15.33 ± 0.57 mm in comparison to other diarrhoeagenic bacteria. Only 10% of the examined curd samples had probiotic bacteria. Isolated strains of Lactobacillus spp. showed satisfactory probiotic potentials in comparison with reference strains and with antibacterial activity against diarrhoeagenic pathogens and thus maybe useful in the management of diarrhoea and also in functional food industry.

  15. Antibiotic resistance of lactic acid bacteria isolated from Chinese yogurts.

    Science.gov (United States)

    Zhou, N; Zhang, J X; Fan, M T; Wang, J; Guo, G; Wei, X Y

    2012-09-01

    The aim of this study was to evaluate the susceptibility of 43 strains of lactic acid bacteria, isolated from Chinese yogurts made in different geographical areas, to 11 antibiotics (ampicillin, penicillin G, roxithromycin, chloramphenicol, tetracycline, chlortetracycline, lincomycin, kanamycin, streptomycin, neomycin, and gentamycin). The 43 isolates (18 Lactobacillus bulgaricus and 25 Streptococcus thermophilus) were identified at species level and were typed by random amplified polymorphic DNA analysis. Thirty-five genotypically different strains were detected and their antimicrobial resistance to 11 antibiotics was determined using the agar dilution method. Widespread resistance to ampicillin, chloramphenicol, chlortetracycline, tetracyclines, lincomycin, streptomycin, neomycin, and gentamycin was found among the 35 strains tested. All of the Strep. thermophilus strains tested were susceptible to penicillin G and roxithromycin, whereas 23.5 and 64.7% of Lb. bulgaricus strains, respectively, were resistant. All of the Strep. thermophilus and Lb. bulgaricus strains were found to be resistant to kanamycin. The presence of the corresponding resistance genes in the resistant isolates was investigated through PCR, with the following genes detected: tet(M) in 1 Lb. bulgaricus and 2 Strep. thermophilus isolates, ant(6) in 2 Lb. bulgaricus and 2 Strep. thermophilus isolates, and aph(3')-IIIa in 5 Lb. bulgaricus and 2 Strep. thermophilus isolates. The main threat associated with these bacteria is that they may transfer resistance genes to pathogenic bacteria, which has been a major cause of concern to human and animal health. To our knowledge, the aph(3')-IIIa and ant(6) genes were found in Lb. bulgaricus and Strep. thermophilus for the first time. Further investigations are required to analyze whether the genes identified in Lb. bulgaricus and Strep. thermophilus isolates might be horizontally transferred to other species.

  16. Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives.

    Science.gov (United States)

    Rokop, Z P; Horton, M A; Newton, I L G

    2015-10-01

    In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific "core" members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of "noncore" and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Magnesium phenylphosphonate: a additive for poly(L-lactic acid)

    Science.gov (United States)

    Cai, Yan-Hua; Zhao, Li-Sha

    2017-03-01

    Developing a advanced additive to promote the crystallization of poly(L-lactic acid) (PLLA) is still one of the main challenges for application. Here, magnesium phenylphosphonate (MgP), as a heterogeneous nucleating agent, was prepared to investigate directly its influence on the crystallization behavior and thermal stability of PLLA via a combination of differential scanning calorimetry (DSC), x-ray diffraction (XRD), and thermogravimetric analysis (TGA). The relevant results, from measurements of non-isothermal crystallization, the glass transition temperature, and XRD after melt crystallization, revealed that the MgP had excellent acceleration effectiveness in the melt crystallization of PLLA, and PLLA-0.7% MgP exhibited the sharpest non-isothermal crystallization peak and the highest non-isothermal crystallization enthalpy, suggesting that 0.7 wt% MgP is the optimal concentration in the PLLA matrix. In addition, these measurements also indicated that the incorporation of MgP could not change the crystal form of PLLA, and the non-isothermal crystallization behavior of PLLA-0.7% MgP did not have a significant relationship with the set final melting temperature. The melting behavior after non-isothermal crystallization further confirmed the crystallization-promoting effect of MgP for PLLA, and the second heating rate significantly affected the melting behavior of PLLA-MgP samples, resulting from the effect of heating rate on formation of crystallites. Thermal stability measurement showed that the addition of MgP could not change the thermal decomposition behavior of the primary PLLA, though MgP exhibited completely different thermal decomposition behavior. Furthermore, the influence of MgP concentration on the thermal decomposition temperatures of PLLA-MgP samples is negligible.

  18. Selection of Lactic Acid Bacteria as Probiotic Candidate for Chicken

    Directory of Open Access Journals (Sweden)

    F. Hamida

    2015-08-01

    Full Text Available Lactic acid bacteria (LAB regarded as safe microorganisms; they can naturally live in gastrointestinal tract, so appropriately used as a probiotic for chicken. This study aimed to select six isolates of LAB (E1223, E3, E4, E5, E7, and E8 to obtain the isolates potentially as probiotic candidate for chicken. The six isolates were derived from spontaneous fermented corn obtained from Laboratory of Animal Biotechnology and Biomedical, PPSHB, Bogor Agricultural University, Indonesia. LAB isolates were tested their susceptibility to antibiotics (bambermycin, erythromycin, chloramphenicol, and tetracycline then were examined in vitro for their tolerance to gastrointestinal pH (2, 3, 4, and 7.2 and 0.5% bile salt condition, antimicrobial activity against Salmonella enteritidis and Enterococcus casseliflavus, and ability to adhere to chicken ileal cells. The results showed the isolates E5, E7, and E8 were sensitive to tetracycline and chloramphenicol, they could survive at pH 2, 3, 4, and 7.2, could survive at 0.5% bile salts, produced antimicrobial activity, and able to adhere to ileal cells (9.40±0.00 Log CFU/cm2 of E8 and were significantly (P<0.05 higher than those of control (5.30±0.14 Log CFU/cm2. In conclusion, this study showed that isolate E8 had better potential compared to isolates E5 and E7 in most in vitro assays as a probiotic candidate for chicken. E5, E7, and E8 were closely related with Pediococcus pentosaceus based on 16S rRNA gene.

  19. A review: Health promoting lactic acid bacteria in traditional Indonesian fermented foods

    OpenAIRE

    Lilis Nuraida

    2015-01-01

    Traditional Indonesian fermented foods can be used as potential sources of probiotics as they commonly contain lactic acid bacteria (LAB), including species of Lactobacillus, Pediococcus, Enterococcus, Weisella and Leuconostoc. The occurrence of LAB in Indonesian fermented foods is not only limited to lactic fermented foods but is also present in foods with molds as the main starter culture. This review aims to describe the significance of Indonesian fermented foods as potential sources of pr...

  20. Lactic Acid Fermentation of Tomato: Effects on cis/trans Lycopene Isomer Ratio, β-Carotene Mass Fraction and Formation of L(+- and D(–-Lactic Acid

    Directory of Open Access Journals (Sweden)

    Daiva Vidmantiene

    2013-01-01

    Full Text Available Fermentation of tomato pulp by the bacteriocin-producing lactic acid bacteria (Lactobacillus sakei KTU05-6, Pediococcus acidilactici KTU05-7 and Pediococcus pentosaceus KTU05-8 was applied as a preservation method for the production of tomato products. The changes in L- and D-lactic acid contents during fermentation of different tomato varieties (Ronaldo and Cunero were analysed. Additionally, the effects of lacto-fermentation on the cis/trans lycopene ratio, β-carotene content, and their relation to colour characteristics of fermented tomato products were investigated. Mass fractions of L- and D-lactic acid in the fermented tomato products varied from (4.25±0.04 to (7.19±0.08 mg per 100 g, and from (4.05±0.05 to (6.34±0.04 mg per 100 g, respectively. Fermentation with P. acidilactici or L. sakei culture resulted in the the decrease of D-lactic acid content by 43.6 and 37.7 %, respectively, compared to spontaneous fermentation. The fermentation with P. pentosaceus or L. sakei increased the content of lycopene on average from 3.70 to 5.68 mg per 100 g, and β-carotene from 0.89 mg per 100 g (in Cunero var. and from 0.28 mg per 100 g (in Ronaldo var. to 1.14 mg per 100 g. Fermentation of tomato with selected lactic acid bacteria resulted in a greater lycopene bioavailability accompanied by an increase in cis-lycopene isomer content.

  1. Enzymatic hydrolysis and fermentability of corn stover pretreated by lactic acid and/or acetic acid.

    Science.gov (United States)

    Xu, Jian; Thomsen, Mette Hedegaard; Thomsen, Anne Belinda

    2009-02-23

    Four different pretreatments with and without addition of low concentration organic acids were carried out on corn stover at 195 degrees C for 15 min. The highest xylan recovery of 81.08% was obtained after pretreatment without acid catalyst and the lowest of 58.78% after pretreatment with both acetic and lactic acid. Glucan recovery was less sensitive to the pretreatment conditions than xylan recovery. The pretreatment with acetic and lactic acid yielded the highest glucan recovery of 95.66%. The glucan recoveries of the other three pretreatments varied between 83.92% and 94.28%. Fermentability tests were performed on liquors obtained from all pretreatments and there were no inhibition effect found in any of the liquors. Simultaneous saccharification and fermentation (SSF) of water-insoluble solids (WIS) showed that a high ethanol yield of 88.7% of the theoretical based on glucose in the raw material was obtained following pretreatment at 195 degrees C for 15 min with acetic acid employed. The estimated total ethanol production was 241.1 kg/ton raw material by assuming fermentation of both C-6 and C-5, and 0.51 g ethanol/g sugar.

  2. Stinging nettle dermatitis.

    Science.gov (United States)

    Anderson, Bryan E; Miller, Christopher J; Adams, David R

    2003-03-01

    The stinging nettle (Urtica dioica) is a common weed that can cause a wide range of cutaneous reactions. Contact with the hairs or spines on the stems and leaves of the stinging nettle causes the release of several biologically active substances. The released chemicals act to cause itching, dermatitis, and urticaria within moments of contact. Extracts from the stinging nettle may provide therapeutic value for some inflammatory medical conditions. There is no standard treatment for stinging nettle dermatitis.

  3. 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).

  4. Characterization and application of lactic acid bacteria for tropical silage preparation.

    Science.gov (United States)

    Pholsen, Suradej; Khota, Waroon; Pang, Huili; Higgs, David; Cai, Yimin

    2016-10-01

    Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid-producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA-DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small-scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science.

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

    Science.gov (United States)

    Berlowska, Joanna; Cieciura, Weronika; Borowski, Sebastian; Dudkiewicz, Marta; Binczarski, Michal; Witonska, Izabela; Otlewska, Anna; Kregiel, Dorota

    2016-10-17

    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.

  6. A platform technology of recovery of lactic acid from a fermentation broth of novel substrate Zizyphus oenophlia.

    Science.gov (United States)

    Bishai, Moumita; De, Swarnalok; Adhikari, Basudam; Banerjee, Rintu

    2015-08-01

    Lactic acid, a biologically derived compound, exists ubiquitously in nature. Its existence ranges from human being to microorganisms. Having paramount industrial significance, lactic acid should be highly pure, devoid of any contaminants. Hence, development of minimum steps of platform technologies to purify it needs urgent attention. The article proposed a novel and simple process for separation of lactic acid from a potential substrate Zizyphus oenophlia, based on ion exchange chromatography. The process herein involves two steps of purification; firstly a weak anion exchange resin was used to separate lactic acid from other anions present in the broth. This was followed by use of strong cation exchanger which washes out the target molecule (lactic acid) while trapped other cations present in the solution. The selected ion exchangers were Amberlite IRA 96 and Amberlite IR 120. Amberlite IRA 96 retained the lactic acid from the broth while washing away other anions. Maximum binding capacity of the resin was found to 210.46 mg lactic acid/g bead. After the simple two-step purification process, the purity of lactic acid improves up to 99.17 % with a recovery yield of 98.9 %. Upon characterization, formation of only levo rotatory form of lactic acid confirms its easy metabolism by the human system, thus triggering its application towards biomaterial sector.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Effects of peroxyacetic acid, acidified sodium chlorite or lactic acid solutions on the microflora of chilled beef carcasses.

    Science.gov (United States)

    Gill, C O; Badoni, M

    2004-02-15

    The effects of solutions of 0.02% peroxyacetic acid, acidified 0.16% sodium chlorite, 2% lactic acid and 4% lactic acid on the natural flora of the distal surfaces of pieces of brisket, from chilled beef carcass quarters delivered from two slaughtering plants to a processing plant, were investigated. Peroxyacetic acid and acidified sodium chlorite solutions had little effect on the numbers of aerobes, coliforms or Escherichia coli on meat from one plant, and were less effective than 4% lactic acid for reducing the numbers of bacteria on meat from the other plant. With meat from both plants, treatment of meat with 4% lactic acid and holding for 5 or 60 min at 7+/-1 degrees C before sampling resulted in reductions of all three groups of bacteria by >/=1.5 log unit. Treatment with 2% lactic acid resulted in similar reductions when meat was sampled 5 min after the treatment, but reductions were about 1 log unit when meat was sampled 60 min after the treatment. Treatment of carcass quarters with 4% lactic acid resulted in reductions of bacterial numbers of >/=2 log units at distal surfaces, but lactic acid may be generally useful as a decontaminant for chilled, raw meat.

  9. New trends and challenges in lactic acid production on renewable biomass

    Directory of Open Access Journals (Sweden)

    Đukić-Vuković Aleksandra J.

    2011-01-01

    Full Text Available Lactic acid is a relatively cheap chemical with a wide range of applications: as a preservative and acidifying agent in food and dairy industry, a monomer for biodegradable poly-lactide polymers (PLA in pharmaceutical industry, precursor and chemical feedstock for chemical, textile and leather industries. Traditional raw materials for fermentative production of lactic acid, refined sugars, are now being replaced with starch from corn, rice and other crops for industrial production, with a tendency for utilization of agro industrial wastes. Processes based on renewable waste sources have ecological (zero CO2 emission, eco-friendly by-products and economical (cheap raw materials, reduction of storage costs advantages. An intensive research interest has been recently devoted to develop and improve the lactic acid production on more complex industrial by-products, like thin stillage from bioethanol production, corncobs, paper waste, straw etc. Complex and variable chemical composition and purity of these raw materials and high nutritional requirements of Lare the main obstacles in these production processes. Media supplementation to improve the fermentation is an important factor, especially from an economic point of view. Today, a particular challenge is to increase the productivity of lactic acid production on complex renewable biomass. Several strategies are currently being explored for this purpose such as process integration, use of Lwith amylolytic activity, employment of mixed cultures of Land/or utilization of genetically engineered microorganisms. Modern techniques of genetic engineering enable construction of microorganisms with desired characteristics and implementation of single step processes without or with minimal pre-treatment. In addition, new bioreactor constructions (such as membrane bioreactors, utilization of immobilized systems are also being explored. Electrodialysis, bipolar membrane separation process, enhanced filtration

  10. [Composition diversity and metabolic characters of lactic acid bacteria community SGL].

    Science.gov (United States)

    Liu, Jingjing; Yang, Fuyu; Wang, Xiaofen; Liu, Jinhuan; Yuan, Xufeng; Cui, Zongjun

    2015-11-04

    We aimed to select a stable lactic acid bacteria community from switchgrass silage, that was efficient in lactic acid production. We obtained the community by continuous restricted subcultivation in MRS broth, and analysed the composition diversity and stability of the community by 16S rRNA gene-based pyrosequencing and Denaturing Gradient Gel Electrophoresis (DGGE), respectively. In addition, we studied the effect of different nitrogen sources on growth and lactic acid production of the community, through adding different concentrations of yeast extraction, different nitrogen sources [yeast extract, peptone, urea and (NH4) 2SO4] and different proportions of (NH4)2SO4 and yeast extract leveled with elemental nitrogen 1.8 g/L. The microbial composition of SGL became stable from the 8th generation according to the results of DGGE. The pH value of the MRS inoculated with SGL dropped to 3.7, and the concentration of lactic acid reached 26 g/L after 24 h cultivation. The result of the pyrosequencing showed that the major composition of SGL were Lactobacillus nantensis (78.78%), Lactobacillus plantarum (7.92%), Lactobacillus pantheris (5.27%), Bacillus coagulans (4.41%) and Lactococcus lactics (3.31%). The best supplementation of yeast extraction for SGL was 20 g/L. When the elemental nitrogen ratio of (NH4) 2SO4 to yeast extract was 1:4, the growth and lactic acid production were no significant difference with 0:5 (P ensilage or lactic acid production. This study would offer theoretical basis for cultivate and application of SGL in production.

  11. Bites and stings.

    Science.gov (United States)

    Charles, Janice; Fahridin, Salma; Britt, Helena

    2009-11-01

    Of the 426 bite or sting problems managed, 312 (73%) were caused by insects. There were 114 other types of bites recorded, the most common being dog and spider bites. There were five cases of toxicity from aquatic animal stings or adverse reactions to bee stings (Table 1).

  12. Hypolipidemic effects of lactic acid bacteria fermented cereal in rats

    Directory of Open Access Journals (Sweden)

    Banjoko Immaculata

    2012-12-01

    Full Text Available Abstract Background The objectives of the present study were to investigate the efficacy of the mixed culture of Lactobacillus acidophilus (DSM 20242, Bifidobacterium bifidum (DSM 20082 and Lactobacillus helveticus (CK60 in the fermentation of maize and the evaluation of the effect of the fermented meal on the lipid profile of rats. Methods Rats were randomly assigned to 3 groups and each group placed on a Diet A (high fat diet into which a maize meal fermented with a mixed culture of Lb acidophilus (DSM 20242, B bifidum (DSM 20082 and Lb helveticus (CK 60 was incorporated, B (unfermented high fat diet or C (commercial rat chow respectively after the first group of 7 rats randomly selected were sacrificed to obtain the baseline data. Thereafter 7 rats each from the experimental and control groups were sacrificed weekly for 4 weeks and the plasma, erythrocytes, lipoproteins and organs of the rats were assessed for cholesterol, triglyceride and phospholipids. Results Our results revealed that the mixed culture of Lb acidophilus (DSM 20242, B bifidum (DSM 20082 and Lb helveticus (CK 60 were able to grow and ferment maize meal into ‘ogi’ of acceptable flavour. In addition to plasma and hepatic hypercholesterolemia and hypertriglyceridemia, phospholipidosis in plasma, as well as cholesterogenesis, triglyceride constipation and phospholipidosis in extra-hepatic tissues characterized the consumption of unfermented hyperlipidemic diets. However, feeding the animals with the fermented maize diet reversed the dyslipidemia. Conclusion The findings of this study indicate that consumption of mixed culture lactic acid bacteria (Lb acidophilus (DSM 20242, Bifidobacterium bifidum (DSM 20082 and Lb helveticus (CK 60 fermented food results in the inhibition of fat absorption. It also inhibits the activity of HMG CoA reductase. This inhibition may be by feedback inhibition or repression of the transcription of the gene encoding the enzyme via activation of the

  13. Effects of lactic acid bacteria silage inoculation on methane emission and productivity of Holstein Friesian dairy cattle

    NARCIS (Netherlands)

    Ellis, J.L.; Hindrichsen, I.K.; Klop, G.; Kinley, R.D.; Milora, N.; Bannink, A.; Dijkstra, J.

    2016-01-01

    Inoculants of lactic acid bacteria (LAB) are used to improve silage quality and prevent spoilage via increased production of lactic acid and other organic acids and a rapid decline in silage pH. The addition of LAB inoculants to silage has been associated with increases in silage digestibility, d

  14. Effects of acetic acid and lactic acid on physicochemical characteristics of native and cross-linked wheat starches.

    Science.gov (United States)

    Majzoobi, Mahsa; Beparva, Paniz

    2014-03-15

    The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties of native and cross-linked wheat starches were investigated prior and after gelatinization. These acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches decreased in the presence of the acids particularly after gelatinization. Water solubility increased while water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic and gummy when acids were added. These changes may indicate the degradation of the starch molecules by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties of both starches before and after gelatinization was greater than acetic acid.

  15. Screening, selection and characterization of phytic acid degrading lactic acid bacteria from chicken intestine.

    Science.gov (United States)

    Raghavendra, Ponnala; Halami, Prakash M

    2009-07-31

    This study was undertaken to screen and select potent phytate degrading lactic acid bacteria and to evaluate their additional characteristic features. Forty lactic acid bacterial strains were isolated from different sources and screened for their ability to degrade myo-inositol hexaphosphate or IP(6) by cobalt chloride staining (plate assay) method, using calcium or sodium salt of phytic acid as substrate. All the forty isolates were able to degrade calcium phytate. However, only two Pediococcus pentosaceus strains (CFR R38 and CFR R35) were found to degrade sodium phytate. These strains showed phytase activity of 213 and 89 U at 50 degrees C, respectively and poor acid phosphatase activity. These strains were further evaluated for additional characteristic features. At pH 2, P. pentosaceus strains CFR R38 and CFR R35 showed 50.7 and 48.5 percentage survivability after 2 h of incubation respectively and they could also withstand 0.3% ox-bile. These cultures exhibited 54.6 and 44.8% of hydrophobicity to xylene, antibacterial activity against food borne pathogens and possessed beta-galactosidase activity. The resistance pattern to several antibiotics was also analyzed. The present study indicates that these strains, having phytate degrading ability and other characteristic features can be exploited as starter cultures in fermented foods to improve the mineral bioavailability.

  16. Identification of Lactic Acid Bacteria and Propionic Acid Bacteria using FTIR Spectroscopy and Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Beata Nalepa

    2012-01-01

    Full Text Available In the present study, lactic acid bacteria and propionic acid bacteria have been identified at the genus level with the use of artificial neural networks (ANNs and Fourier transform infrared spectroscopy (FTIR. Bacterial strains of the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Propionibacterium were analyzed since they deliver health benefits and are routinely used in the food processing industry. The correctness of bacterial identification by ANNs and FTIR was evaluated at two stages. At first stage, ANNs were tested based on the spectra of 66 reference bacterial strains. At second stage, the evaluation involved 286 spectra of bacterial strains isolated from food products, deposited in our laboratory collection, and identified by genus-specific PCR. ANNs were developed based on the spectra and their first derivatives. The most satisfactory results were reported for the probabilistic neural network, which was built using a combination of W5W4W3 spectral ranges. This network correctly identified the genus of 95 % of the lactic acid bacteria and propionic acid bacteria strains analyzed.

  17. Extraction, isolation and purification of exopolysaccharide from lactic acid bacteria using ethanol precipitation method

    Directory of Open Access Journals (Sweden)

    Vivek K. Bajpai

    2016-09-01

    Full Text Available Lactic acid bacteria are classified ‘Generally Recognized As Safe’ (GRAS with most effective potential to divert significant amount of fermentable sugars towards the biosynthesis of functional exopolysaccharide. Exopolysaccharides from lactic acid bacteria are receiving a renewed interest due to the claims of human health benefits, such as modulation of immune response system and more importantly in food and pharma industries as a texturizer, viscosifer, emulsifier and syneresis-lowering agent. Its purification methodology involves: a Extraction of cell-free supernatant from lactic acid bacteria; b Denature of protein using trichloroacetic acid; c Ethanol precipitation; d Dialysis; and e Freeze drying. However, depending on nature of research, compounds can be further purified using scanning electron microscopy (SEM, infrared spectrum (IR; and nuclear magnetic resonance (NMR spectral analyses.

  18. Physicochemical Properties and Applications of Poly(lactic-co-glycolic acid) for Use in Bone Regeneration

    Science.gov (United States)

    Félix Lanao, Rosa P.; Jonker, Anika M.; Wolke, Joop G.C.; Jansen, John A.; van Hest, Jan C.M.

    2013-01-01

    Poly(lactic-co-glycolic acid) (PLGA) is the most often used synthetic polymer within the field of bone regeneration owing to its biocompatibility and biodegradability. As a consequence, a large number of medical devices comprising PLGA have been approved for clinical use in humans by the American Food and Drug Administration. As compared with the homopolymers of lactic acid poly(lactic acid) and poly(glycolic acid), the co-polymer PLGA is much more versatile with regard to the control over degradation rate. As a material for bone regeneration, the use of PLGA has been extensively studied for application and is included as either scaffolds, coatings, fibers, or micro- and nanospheres to meet various clinical requirements. PMID:23350707

  19. Oxidation and hydrolysis of lactic acid in near-critical water

    Energy Technology Data Exchange (ETDEWEB)

    Li, L.; Vallejo, D.; Gloyna, E.F. [Univ. of Texas, Austin, TX (United States). Civil Engineering Dept.; Portela, J.R. [Univ. de Cadiz (Spain). Dept. de Ingenieria Quimica

    1999-07-01

    Hydrothermal reactions (oxidation and hydrolysis) involving lactic acid (LA) were studied at temperatures ranging from 300 to 400 C and a nominal pressure of 27.6 MPa. Kinetic models were developed with respect to concentrations of LA and total organic carbon (TOC), respectively. On the basis of identified liquid and gaseous products, pathways for hydrothermal reactions involving lactic acid were proposed. Acetic acid and acetaldehyde were confirmed as the major liquid intermediates for oxidation and hydrolysis reactions, respectively. Carbon monoxide and methane were identified as the major gaseous byproducts from these reactions. These results demonstrate the potential of completely oxidizing, as well as converting, lactic acid into other organic products, in high-temperature water.

  20. 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.

  1. Efficient production of L-lactic acid from cassava powder by Lactobacillus rhamnosus.

    Science.gov (United States)

    Wang, Limin; Zhao, Bo; Liu, Bo; Yang, Chunyu; Yu, Bo; Li, Qinggang; Ma, Cuiqing; Xu, Ping; Ma, Yanhe

    2010-10-01

    Cassava is one of the most efficient and rich crops in terms of carbohydrate production, which is a tropical perennial plant that grows on poor or depleted soils. Microbial conversion of such a renewable raw material to useful products is an important objective in industrial biotechnology. L-Lactic acid was efficiently produced from cassava powder by a Lactobacillus rhamnosus strain CASL. The fermentation properties of cassava powder were compared with those of glucose and corn powder. The efficiencies of various fermentation strategies for L-lactic acid production from cassava powder, including simultaneous saccharification and fermentation (SSF), two-step fermentation (TSF) and simultaneous liquefaction, saccharification and fermentation (SLSF), were investigated. The high L-lactic acid concentration (175.4 g/l) was obtained using 275 g/l of cassava powder concentration (total sugar of 222.5 g/l) in SSF batch fermentation. This is the highest L-lactic acid concentration reported, from cassava source, and it provides an efficient L-lactic acid production process with cheap raw bioresources, such as cassava powder.

  2. 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.

  3. Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes

    Institute of Scientific and Technical Information of China (English)

    Chengdong Piao; Peng Li; Guangyao Liu; Kun Yang

    2013-01-01

    Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. Ten sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds, the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require-ments for a biomaterial used to repair sciatic nerve injury.

  4. Wheat bran biorefinery--an insight into the process chain for the production of lactic acid.

    Science.gov (United States)

    Tirpanalan, Özge; Reisinger, Michael; Smerilli, Marina; Huber, Florian; Neureiter, Markus; Kneifel, Wolfgang; Novalin, Senad

    2015-03-01

    The present study investigates a wheat bran biorefinery including major processing steps pre-extraction, pre-treatment and lactic acid fermentation. Concerning the dry mass distribution, during the pre-extraction 32% of the feedstock was recovered, offering some perspectives for applications in food area. The pre-treatment (hydrothermal/enzymatic hydrolysis) of the remaining cake solubilized 34% of dry mass and led to a fermentable sugar concentration of 21g/L. The fermentation resulted in a lactic acid yield of 0.73g/g substrate. Concentrating the fermentation feed via nanofiltration did not improve the lactic acid productivity. Taking into account that Lactobacillus pentosus, a heterofermentative microorganism was used, the dry mass balance revealed a product yield of 47% (32% extract, 15% lactic acid). Based on a theoretical consideration involving a cellulolytic enzyme production (10% feedstock allocation) and lignin utilization, under optimized conditions a maximum product yield of around 80% (35% extract, 39% lactic acid, 6% lignin) could be expected. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Antimicrobial activity of ethanol, glycerol monolaurate or lactic acid against Listeria monocytogenes.

    Science.gov (United States)

    Oh, D H; Marshall, D L

    1993-12-01

    Minimal inhibitory concentrations (MIC) and antimicrobial effects of glycerol monolaurate (monolaurin), ethanol and lactic acid, either alone or in combination, against Listeria monocytogenes in tryptic soy broth were determined. Ethanol at concentrations up to 1.25% did not inhibit growth, but growth was strongly inhibited in the presence of 5% ethanol. MIC values of monolaurin and ethanol alone were 10 micrograms/ml (0.001%) and 50,000 micrograms/ml (5%), respectively. However, MIC values were not changed when monolaurin was combined with ethanol. When 5 micrograms/ml monolaurin was combined with 5% ethanol, the inhibitory effect of the combination was similar to the most active compound alone after 24 h incubation. These data indicate little interaction between monolaurin and ethanol against L. monocytogenes. MIC value of lactic acid alone was 5000 micrograms/ml (0.5%), but was lower when 1.25% ethanol was combined with 0.25% lactic acid. When 2.5% ethanol was combined with 0.25% lactic acid, the combination did not increase the inhibitory effect of the most active single compound alone. This result also indicates that there was little interaction between ethanol and lactic acid.

  6. Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes.

    Science.gov (United States)

    Piao, Chengdong; Li, Peng; Liu, Guangyao; Yang, Kun

    2013-11-25

    Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. Ten sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds, the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require-ments for a biomaterial used to repair sciatic nerve injury.

  7. Detoxification of Sap from Felled Oil Palm Trunks for the Efficient Production of Lactic Acid.

    Science.gov (United States)

    Kunasundari, Balakrishnan; Arai, Takamitsu; Sudesh, Kumar; Hashim, Rokiah; Sulaiman, Othman; Stalin, Natra Joseph; Kosugi, Akihiko

    2017-03-30

    The availability of fermentable sugars in high concentrations in the sap of felled oil palm trunks and the thermophilic nature of the recently isolated Bacillus coagulans strain 191 were exploited for lactic acid production under non-sterile conditions. Screening indicated that strain 191 was active toward most sugars including sucrose, which is a major component of sap. Strain 191 catalyzed a moderate conversion of sap sugars to lactic acid (53%) with a productivity of 1.56 g/L/h. Pretreatment of oil palm sap (OPS) using alkaline precipitation improved the sugar fermentability, providing a lactic acid yield of 92% and productivity of 2.64 g/L/h. To better characterize potential inhibitors in the sap, phenolic, organic, and mineral compounds were analyzed using non-treated sap and saps treated with activated charcoal and alkaline precipitation. Phthalic acid, 3,4-dimethoxybenzoic acid, aconitic acid, syringic acid, and ferulic acid were reduced in the sap after treatment. High concentrations of Mg, P, K, and Ca were also precipitated by the alkaline treatment. These results suggest that elimination of excess phenolic and mineral compounds in OPS can improve the fermentation yield. OPS, a non-food resource that is readily available in bulk quantities from plantation sites, is a promising source for lactic acid production.

  8. Use of ionic chromatography in determining the contamination of apple juice by lactic acid.

    Science.gov (United States)

    Wojtczak, M; Antczak, A; Przybyt, M

    2010-06-01

    High-performance anion exchange chromatography (HPAEC) with conductometric detection was used for the determination of the lactic acid content of apple juice subjected to fermentation with the strains of Lactobacillus brevis and Lactobacillus plantarum, obtained from a collection, at 20 and 30 degrees C. At the same time, lactate content was determined by means of enzymatic tests and biosensors. Lactic acid concentrations determined by the chromatographic method are similar to those obtained during analysis by enzymatic tests. However, acid concentrations determined by means of biosensors substantially diverge from these results.

  9. Lactic Acid Permeabilizes Gram-Negative Bacteria by Disrupting the Outer Membrane

    OpenAIRE

    Alakomi, H.-L.; Skyttä, E.; Saarela, M; Mattila-Sandholm, T.; Latva-Kala, K.; Helander, I M

    2000-01-01

    The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH...

  10. Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

    OpenAIRE

    Muriel eAldunate; Daniela eSrbinovski; Anna C Hearps; Latham, Catherine F.; Paul A Ramsland; Raffi eGugasyan; Cone, Richard A.; Gilda eTachedjian

    2015-01-01

    Lactic acid and short chain fatty acids (SCFAs) produced by vaginal microbiota have reported antimicrobial and immune modulatory activities indicating their potential as biomarkers of disease and/or disease susceptibility. In asymptomatic women of reproductive-age the vaginal microbiota is comprised of lactic acid-producing bacteria that are primarily responsible for the production of lactic acid present at ~110 mM and acidifying the vaginal milieu to pH ~3.5. In contrast, bacterial vaginosis...

  11. Improvement of the lactic acid fermentation of capers through an experimental factorial design (Capparis spinosa L

    Directory of Open Access Journals (Sweden)

    Errachidi, F.

    2010-12-01

    Full Text Available The study of the caper fermentation process through an experiment factorial plan allows us to determine a function ƒ such that (Y= ƒ(X1, X2, …, Xn existing between magnitude Y which is the decrease of pH (called response, and variables Xi , which are brine, lactic acid, citric acid and lactic ferment (called factors. A complete factorial plan 24 was made in order to determine the factors and the interactions among the factors which have a statistically significant influence on the studied response. Brine, lactic acid and citric acid have a significant effect on the fall of pH; by contrast, lactic ferment does not have a significant effect. On the other hand, the interactions between brine and lactic acid, between brine and lactic ferment , between lactic acid with citric acid and between lactic acid with lactic ferment have significant effects on the fall of pH (p El estudio del proceso de fermentación mediante un diseño factorial nos permitió determinar una función ƒ (Y= ƒ(X1, X2, …, Xn que existe entre la magnitud Y que es la disminución del pH (llamada respuesta, y las variables X, que son la salmuera, ácido láctico, ácido cítrico y los fermentos lácticos (llamados factores. Un completo plan factorial 24 fue hecho con objeto de determinar los factores y las interacciones entre los factores que tienen una influencia estadísticamente significativa en la respuesta estudiada. La salmuera, ácido láctico y ácido cítrico tienen un efecto significativo en la caída del pH; por el contrario, los fermentos lácticos no tienen efecto significativo. Por otra parte, las interacciones entre salmuera y ácido láctico, salmuera y fermentos lácticos, ácido láctico y ácido cítrico, y ácido láctico y fermentos lácticos tuvieron un efecto significativo en la caída del pH (p < 0.0001. La fermentación fue hecha en el laboratorio de investigación de la Sociedad Marocapres-Fez líder Internacional en la transformación de

  12. Stereocomplexation of low molecular weight poly(L-lactic acid) and high molecular weight poly(D-lactic acid), radiation crosslinking PLLA/PDLA stereocomplexes and their characterization

    Science.gov (United States)

    Quynh, Tran Minh; Mai, Hoang Hoa; Lan, Pham Ngoc

    2013-02-01

    Poly(L-lactic acid)s (PLLAx) were synthesized from L-lactic acid by polycondensation. Different stereocomplexes were also obtained with equimolar mixtures of synthesized PLLAx and a commercial PDLA. The stereocomplexes were crosslinked with triallyl isocyanurate (TAIC) by gamma irradiation. Crosslinking density increased with radiation doses, the heavier the crosslinking network, the lower its swelling degree. The crosslinking structures were introduced in the stereocomplexes inhibiting the mobility for crystallization of PLLA molecules. Thermal and mechanical properties of PLA stereocomplexes were remarkably enhanced by radiation induced crosslinking. PLA stereocomplex does not seem to be degraded by PLLA degrading microorganisms existing in compost at room temperature, but the synthesized PLLA was significantly degraded.

  13. Microbial export of lactic and 3-hydroxypropanoic acid : implications for industrial fermentation processes

    NARCIS (Netherlands)

    van Maris, AJA; Konings, WN; Pronk, Jack T.; Dijken, J.P. van

    2004-01-01

    Lactic acid and 3-hydroxypropanoic acid are industrially relevant microbial products. This paper reviews the current knowledge on export of these compounds from microbial cells and presents a theoretical analysis of the bioenergetics of different export mechanisms. It is concluded that export can be

  14. Development of Conducting Polyaniline/ Poly(Lactic Acid) Nanofibers by Electrospinning

    Science.gov (United States)

    Ultrafine fibers consisting of blends of polyaniline doped with p-toluene sulfonic acid and poly(L-lactic acid) were prepared by electrospinning. The presence of polyaniline resulted in fibers with diameters as thin as 100– 200 nm and a significant reduction of bead formation. These fibers were visu...

  15. Equilibria and kinetics for reactive extraction of lactic acid using Alamine 336 in decanol

    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 this from aqueous solution is a growing requirement in fermentation-based industries. The design of an amine extraction process requires (i) equilibrium and (ii) kinetic data for the acid-amine (solvent) system used. The equilibrium compl

  16. Microbial export of lactic and 3-hydroxypropanoic acid : implications for industrial fermentation processes

    NARCIS (Netherlands)

    van Maris, AJA; Konings, WN; Pronk, Jack T.; Dijken, J.P. van

    2004-01-01

    Lactic acid and 3-hydroxypropanoic acid are industrially relevant microbial products. This paper reviews the current knowledge on export of these compounds from microbial cells and presents a theoretical analysis of the bioenergetics of different export mechanisms. It is concluded that export can be

  17. Report membrane transport of lactic acid in the filamentous fungus Rhizopus

    Science.gov (United States)

    The fungus Rhizopus is frequently used for fermentative production of lactic acid, but little is known about the mechanisms or proteins for transporting this carboxylic acid. Since transport of the lactate anion across the plasma membrane is critical to prevent acidification of the cytoplasm, we ev...

  18. Occurrence and role of lactic acid bacteria in seafood products.

    Science.gov (United States)

    Françoise, Leroi

    2010-09-01

    Lactic acid bacteria (LAB) in fish flesh has long been disregarded because the high post-mortem pH, the low percentage of sugars, the high content of low molecular weight nitrogenous molecules and the low temperature of temperate waters favor the rapid growth of pH-sensitive psychrotolerant marine Gram-negative bacteria like Pseudomonas, Shewanella and Photobacterium. In seafood packed in both vacuum (VP) and modified atmosphere (MAP) packaging commonly CO(2) enriched, the growth of the Gram-negative aerobic bacteria group (predominantly pseudomonads) is effectively inhibited and the number reached by LAB during storage is higher than that achieved in air but always several log units lower than the trimethylamine oxide (TMA-O) reducing and CO(2)-resistant organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Accordingly, LAB are not of much concern in seafood neither aerobically stored nor VP and MAP. However, they may acquire great relevance in lightly preserved fish products (LPFP), including those VP or MAP. Fresh fish presents a very high water activity (aw) value (0.99). However, aw is reduced to about 0.96 when salt (typically 6% WP) is added to the product. As a result, aerobic Gram-negative bacteria are inhibited, which allows the growth of other organisms more resistant to reduced aw, i.e. LAB, and then they may acquire a central role in the microbial events occurring in the product. Changes in consumers' habits have led to an increase of convenient LPFP with a relative long shelf-life (at least 3 weeks) which, on the other hand, may constitute a serious problem from a safety perspective since Listeria monocytogenes and sometimes Clostridium botulinum (mainly type E) may able to grow. In any case the LAB function in marine products is complex, depending on species, strains, interaction with other bacteria and the food matrix. They may have no particular effect or they may be responsible for spoilage and, in certain cases, they may even exert

  19. Phylogenomic reconstruction of lactic acid bacteria: an update

    Directory of Open Access Journals (Sweden)

    Yu Li

    2011-01-01

    Full Text Available Abstract Background Lactic acid bacteria (LAB are important in the food industry for the production of fermented food products and in human health as commensals in the gut. However, the phylogenetic relationships among LAB species remain under intensive debate owing to disagreements among different data sets. Results We performed a phylogenetic analysis of LAB species based on 232 genes from 28 LAB genome sequences. Regardless of the tree-building methods used, combined analyses yielded an identical, well-resolved tree topology with strong supports for all nodes. The LAB species examined were divided into two groups. Group 1 included families Enterococcaceae and Streptococcaceae. Group 2 included families Lactobacillaceae and Leuconostocaceae. Within Group 2, the LAB species were divided into two clades. One clade comprised of the acidophilus complex of genus Lactobacillus and two other species, Lb. sakei and Lb. casei. In the acidophilus complex, Lb. delbrueckii separated first, while Lb. acidophilus/Lb. helveticus and Lb. gasseri/Lb. johnsonii were clustered into a sister group. The other clade within Group 2 consisted of the salivarius subgroup, including five species, Lb. salivarius, Lb. plantarum, Lb. brevis, Lb. reuteri, Lb. fermentum, and the genera Pediococcus, Oenococcus, and Leuconostoc. In this clade, Lb. salivarius was positioned most basally, followed by two clusters, one corresponding to Lb. plantarum/Lb. brevis pair and Pediococcus, and the other including Oenococcus/Leuconostoc pair and Lb. reuteri/Lb. fermentum pair. In addition, phylogenetic utility of the 232 genes was analyzed to identify those that may be more useful than others. The genes identified as useful were related to translation and ribosomal structure and biogenesis (TRSB, and a three-gene set comprising genes encoding ultra-violet resistance protein B (uvrB, DNA polymerase III (polC and penicillin binding protein 2B (pbpB. Conclusions Our phylogenomic analyses

  20. More value from food waste: Lactic acid and biogas recovery.

    Science.gov (United States)

    Kim, Mi-Sun; Na, Jeong-Geol; Lee, Mo-Kwon; Ryu, Hoyoung; Chang, Yong-Keun; Triolo, Jin M; Yun, Yeo-Myeong; Kim, Dong-Hoon

    2016-06-01

    Anaerobic digestion (AD) is one of the traditional technologies for treating organic solid wastes, but its economic benefit is sometimes questioned. To increase the economic feasibility of the treatment process, the aim of this study was to recover not only biogas from food waste but lactic acid (LA) as well. At first, LA fermentation of food waste (FW) was conducted using an indigenous mixed culture. During the operation, temperature was gradually increased from 35 °C to 55 °C, with the highest performance attained at 50 °C. At 50 °C and hydraulic retention time (HRT) of 1.0 d, LA concentration in the broth was 40 kg LA/m(3), corresponding to a yield of 1.6 mol LA/mol hexoseadded. Pyrosequencing results showed that Lactobacillus (97.6% of the total number of sequences) was the predominant species performing LA fermentation of FW. The fermented broth was then centrifuged and LA was extracted from the supernatant by the combined process of nanofiltration and water-splitting electrodialysis. The process could recover highly purified LA by removing 85% of mineral ions such as Na(+), K(+), Mg(2+), and Ca(2+) and 90% of residual carbohydrates. Meanwhile, the solid residue remained after centrifugation was further fermented to biogas by AD. At HRT 40 d (organic loading rate of 7 kg COD/m(3)/d), the highest volumetric biogas production rate of 3.5 m(3)/m(3)/d was achieved with a CH4 yield of 0.25 m(3) CH4/kg COD. The mass flow showed that 47 kg of LA and 54 m(3) of biogas could be recovered by the developed process from 1 ton of FW with COD removal efficiency of 70%. These products have a higher economic value 60 USD/ton FW compared to that of conventional AD (27 USD/ton FW).

  1. Optimization of a biomimetic poly-(lactic acid) ligament scaffold

    Science.gov (United States)

    Uehlin, Andrew F.

    The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, often requiring orthopedic reconstruction using autograft or allograph tissue, both with significant disadvantages. As a result, tissue engineering an ACL replacement graft has been heavily investigated. The present study attempts to replicate the morphology and mechanical properties of the ACL using a nanomatrix composite of highly-aligned poly(lactic acid) (PLA) fibers with various surface and biochemical modifications. Additionally, this study attempts to recreate the natural mineralization gradient found at the ACL enthesis onto the scaffold, capable of inducing a favorable cellular response in vitro. Unidirectional electrospinning was used to create nanofibers of PLA, followed by an induced degradation of the nanofibers via 0.25M NaOH hydrolysis. The effects of the unidirectional electrospinning as well as the effects of NaOH hydrolysis on fiber alignment, fiber diameter, surface morphology, crystallinity, in vitro swelling, immobilization of fibrin, and mechanical properties were investigated, resulting in a modified morphology correlating to the microstructure of native ligament tissue with similar mechanical properties. Furthering the development of the PLA nanomatrix composite, a bioinkjet printer was used to immobilize nanoparticulate hydroxyapatite (HANP) on the surface of the scaffold. A series of 300pL droplets of HANP bioink were printed over a gradient pattern mimetic of (and spatially corresponding to) the mineralization gradient found over the microanatomy at the ACL enthesis. Proliferation and differentiation response of human mesenchymal stem cells (hMSCs) in vitro was assessed on a variety of conditions and combinations of the PLA nanofiber scaffold surface modifications (inclusive and exclusive of HANP, fibrin, and various time dependent NaOH treatments). It was found that a combinatory effect of the HANP gradient with fibrin on 20 minute NaOH treated PLA

  2. Preservation of acidified cucumbers with a natural preservative combination of fumaric acid and allyl isothiocyanate that target lactic acid bacteria and yeasts

    Science.gov (United States)

    Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but sp...

  3. 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.

  4. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    Science.gov (United States)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  5. Lactic acid production by Rhizopus oryzae transformants with modified lactate dehydrogenase activity.

    Science.gov (United States)

    Skory, C D

    2004-04-01

    Rhizopus oryzae is capable of producing high levels of lactic acid by the fermentation of glucose. Yields typically vary over 60-80%, with the remaining glucose diverted primarily into ethanol fermentation. The goal of this work was to increase lactate dehydrogenase (LDH) activity, so lactic acid fermentation could more effectively compete for available pyruvate. Three different constructs, pLdhA71X, pLdhA48XI, and pLdhA89VII, containing various lengths of the ldhA gene fragment, were transformed into R. oryzae. This fungus rarely integrates DNA used for transformation, but instead relies on extra-chromosomal replication in a high-copy number. Plasmid pLdhA48XI was linearized prior to transformation in order to facilitate integration into the pyrG gene used for selection. Isolates transformed with ldhA containing plasmid were compared with both the wild-type parent strain and the auxotrophic recipient strain containing vector only. All isolates transformed with pLdhA71X or pLdhA48XI had multiple copies of the ldhA gene that resulted in ldhA transcript accumulation, LDH specific activity, and lactic acid production higher than the controls. Integration of plasmid pLdhA48XI increased the stability of the strain, but did not seem to offer any benefit for increasing lactic acid production. Since lactic acid fermentation competes with ethanol and fumaric acid production, it was not unexpected that increased lactic acid production was always concomitant with decreased ethanol and fumaric acid. Plasmid pLdhA71X, containing a large ldhA fragment (6.1 kb), routinely yielded higher levels of lactic acid than the smaller region (3.3 kb) used to construct plasmid pLdhA48XI. The greatest levels of ldhA transcript and enzyme production occurred with isolates transformed with plasmid pLdhA89VII. However, these transformants always produced less lactic acid and higher amounts of ethanol, fumaric, and glycerol compared with the control.

  6. 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.

  7. Complete Genome Sequence of a thermotolerant sporogenic lactic acid bacterium, Bacillus coagulans strain 36D1

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, Mun Su [University of Florida, Gainesville; Moritz, Brelan E. [University of Florida, Gainesville; Xie, Gary [Los Alamos National Laboratory (LANL); Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Chertkov, Olga [Los Alamos National Laboratory (LANL); Brettin, Thomas S [ORNL; Han, Cliff [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Patel, Milind [University of Florida, Gainesville; Ou, Mark [University of Florida, Gainesville; Harbrucker, Roberta [University of Florida, Gainesville; Ingram, Lonnie O. [University of Florida; Shanmugam, Keelnathan T. [University of Florida

    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 spo- rogenic lactic acid bacterium to grow at 50-55 C and pH 5.0 makes this organism an attrac- tive 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 se- quence of a representative strain, B. coagulans strain 36D1, is presented and discussed.

  8. Capacity of lactic acid bacteria in immunity enhancement and cancer prevention.

    Science.gov (United States)

    Riaz Rajoka, Muhammad Shahid; Shi, Junling; Zhu, Jing; Shao, Dongyan; Huang, Qingsheng; Yang, Hui; Jin, Mingliang

    2017-01-01

    Lactic acid bacteria are associated with the human gastrointestinal tract. They are important for maintaining the balance of microflora in the human gut. An increasing number of published research reports in recent years have denoted the importance of producing interferon-gamma and IgA for treatment of disease. These agents can enhance the specific and nonspecific immune systems that are dependent on specific bacterial strains. The mechanisms of these effects were revealed in this investigation, where the cell walls of these bacteria were modulated by the cytokine pathways, while the whole bacterial cell mediated the host cell immune system and regulated the production of tumor necrosis factors and interleukins. A supplement of highly active lactic acid bacteria strains provided significant potential to enhance host's immunity, offering prevention from many diseases including some cancers. This review summarizes the current understanding of the function of lactic acid bacteria immunity enhancement and cancer prevention.

  9. Applications for biotechnology: present and future improvements in lactic acid bacteria.

    Science.gov (United States)

    McKay, L L; Baldwin, K A

    1990-09-01

    The lactic acid bacteria are involved in the manufacture of fermented foods from raw agricultural materials such as milk, meat, vegetables, and cereals. These fermented foods are a significant part of the food processing industry and are often prepared using selected strains that have the ability to produce desired products or changes efficiently. The application of genetic engineering technology to improve existing strains or develop novel strains for these fermentations is an active research area world-wide. As knowledge about the genetics and physiology of lactic acid bacteria accumulates, it becomes possible to genetically construct strains with characteristics shaped for specific purposes. Examples of present and future applications of biotechnology to lactic acid bacteria to improve product quality are described. Studies of the basic biology of these bacteria are being actively conducted and must be continued, in order for the food fermentation industry to reap the benefits of biotechnology.

  10. Lipase-catalyzed esterification of lactic acid with straight-chain alcohols

    DEFF Research Database (Denmark)

    Rønne, Torben Harald; Xu, Xuebing; Tan, Tianwei

    2005-01-01

    Enzymatic synthesis of esters of lactic acid and straight-chain alcohols with different chain lengths (C6–C18) were investigated in batch reactions with hexadecanol (C16) as the model alcohol. Cyclohexane was the best solvent for higher ester yields, and the best biocatalyst was the immobilized...... of lactic acid to alcohol, each at a concentration of 120 mM each; a 50°C reaction temperature; 190 rpm shaking speed; and the addition of 100 mg molecular sieves (4 Å) for drying. The ester yield increased with increasing lipase load, and a yield of 79.2% could be obtained after 24 h of reaction at 20 wt......% of Novozym 435. The immobilized Candida sp. lipase prepared in the laboratory also could be used to produce esters of lactic acid and straight-chain alcohols, but it had a much lower activity than Novozym 435 with a temperature optimum of 40°C....

  11. A novel process for recovery and refining of L-lactic acid from fermentation broth.

    Science.gov (United States)

    Chen, Lijun; Zeng, Aiwu; Dong, Haibo; Li, Qi; Niu, Congcong

    2012-05-01

    This paper introduces a novel process for recovery and refining of L-lactic acid from a fermentation broth. The use of a solvent extraction step, in the novel approach, has significant impacts on the following centrifugal short-path distillation conditions (operating pressure, evaporator temperature and feed flow rate). As the conditions were varied, the l-lactic acid purity and yield in the distillate were monitored. For the purpose of comparison, a series of experiments were also carried out using the existing purification process. The results showed that both of the two processes can obtain l-lactic acid with a high purity around 91.3%, while the yield obtained using the novel process reached 61.73%, which was about 20.43% higher than that using the existing process. Additionally, multiple-pass distillation observed special attention by improving the yield up to 74.63%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. A study of parameters affecting the solvent extraction of lactic acid from fermentation broth

    Directory of Open Access Journals (Sweden)

    I. S. Udachan

    2014-09-01

    Full Text Available Lactic acid has recently been drawing much interest as a raw material for biodegradable polymer. One of the promising technologies for recovery of lactic acid from fermentation broth is reactive liquid - liquid extraction. Equilibrium studies on the reactive extraction of lactic acid with trioctylamine (TOA in various organic phases and its re-extraction into aqueous solutions were carried out. In this study distribution coefficient, extractability, stripping efficiency of various active and inert diluents with TOA as extractant were investigated, which were higher for active diluents. The effects of operating temperature, speed of agitation, agitation time and diluent composition on extraction efficiency were also studied. Temperature and extraction efficiency were inversely proportional to each other, whereas extraction efficiency was little affected by speed of agitation and agitation time.

  13. Structure/Property Relationships of Poly(L-lactic Acid/Mesoporous Silica Nanocomposites

    Directory of Open Access Journals (Sweden)

    Javier Gudiño-Rivera

    2013-01-01

    Full Text Available Biodegradable poly(L-lactic acid (PLLA/mesoporous silica nanocomposites were prepared by grafting L-lactic acid oligomer onto silanol groups at the surface of mesoporous silica (SBA-15. The infrared results showed that the lactic acid oligomer was grafted onto the mesoporous silica. Surface characterization of mesoporous silica proved that the grafted oligomer blocked the entry of nitrogen into the mesopores. Thermal analysis measurements showed evidence that, once mixed with PLLA, SBA-15 not only nucleated the PLLA but also increased the total amount of crystallinity. Neat PLLA and its nanocomposites crystallized in the same crystal habit and, as expected, PLLA had a defined periodicity compared with the nanocomposites. This was because the grafted macromolecules on silica tended to cover the lamellar crystalline order. The g-SBA-15 nanoparticles improved the tensile moduli, increasing also the tensile strength of the resultant nanocomposites. Overall, the silica concentration tended to form a brittle material.

  14. 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

    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...... 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...... 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...

  15. Lactic acid production from corn stover using mixed cultures of Lactobacillus rhamnosus and Lactobacillus brevis.

    Science.gov (United States)

    Cui, Fengjie; Li, Yebo; Wan, Caixia

    2011-01-01

    Mixed cultures of Lactobacillus rhamnosus and Lactobacillus brevis was studied for improving utilization of both cellulose- and hemicellulose-derived sugars from corn stover for lactic acid production. During simultaneous saccharification and fermentation (SSF) of NaOH-treated corn stover by the mixed cultures, a lactic acid yield of 0.70 g/g was obtained, which was about 18.6% and 29.6% higher than that by single cultures of L. rhamnosus and L. brevis, respectively. Our results indicated that lactic acid yield from NaOH-pretreated corn stover by mixed cultures of L. rhamnosus and L. brevis was comparable to that from pure sugar mixtures (0.73 g/g of glucose/xylose mixture at 3:1 w/w). Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Convenient synthetic method of starch/lactic acid graft copolymer catalyzed with sodium hydroxide

    Indian Academy of Sciences (India)

    Qingling Wang; Yingmo Hu; Jianhua Zhu; Yang Liu; Xue Yang; Jing Bian

    2012-06-01

    Copolymer of starch grafted with lactic acid (LA) could be directly prepared by reaction of cornstarch with lactic acid and with sodium hydroxide (NaOH) as the catalyst. The structure of starch/LA copolymer was characterized by IR, XRD, SEM and 1H-NMR. The effects of NaOH concentration, ratios of starch and LA, reaction temperature and reaction time on the grafting degree were also investigated and the results showed that the highest grafting degree of starch could reach 33.60% when the graft copolymerization was carried out in 0.40 mol l-1 NaOH aqueous solution for 9 h at 90°C with 1: 6 ratio of starch and lactic acid.

  17. Research on flux decline in nanofiltration of lactic acid solutions with ZRIV/PAA membranes application

    Directory of Open Access Journals (Sweden)

    Połom Ewa

    2016-09-01

    Full Text Available The efficiency of lactic acid solutions nanofiltration with dynamically formed zirconium (IV hydrous oxide polyacrylate (ZrIV/PAA membranes application were considered in this paper. The results of investigations on flux decline in nanofiltration of lactic acid solutions under conditions resulting in low and high lactic acid rejection are reported. In the long term experimental research on pressure driven membrane processes the main reason of permeate flux reduction is an accumulation of concentration polarization and fouling effects. The experimental permeate flux versus time curves were analyzed in the frame of resistance-in-series model with the aim to develop the characteristic fouling and concentration polarization resistances. The analysis of experimental data and results of calculations showed that both: concentration polarization and fouling phenomena in investigated system depend on hydrodynamic conditions and properties of filtered solutions and (ZrIV/PAA membrane.

  18. Production of γ-Amino Butyric Acid in Tea Leaves wit Treatment of Lactic Acid Bacteria

    Science.gov (United States)

    Watanabe, Yuko; Hayakawa, Kiyoshi; Ueno, Hiroshi

    Lactic acid bacteria was searched for producing termented tea that contained a lot of γ-amino butyric acid(GABA). Also examined were the growth condition, GABA production and changes in catechin contents in the tea leaves. Lactobacillus brevis L12 was found to be suitable for the production of fermented tea since it gave as much GABA as gabaron tea when tea leaves being suspended with water at 10% and incubated for 4 days at 25°C. The amount of GABA produced was more than calculated based upon the content of glutamic acid in tea leaves. It is probable to assume that glutamate derived from glutamine and theanine is converted into GABA.

  19. Relationship of plasma creatinine and lactic acid in type 2 diabetic patients without renal dysfunction

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; LU Jun-xi; TANG Jun-ling; LI Li; LU Hui-juan; HOU Xu-hong; JIA Wei-ping; XIANG Kun-san

    2009-01-01

    Background As one of most widely-used biguanides,metformin can induce the lactic acidosis in patients with renal failure though its incidence is very low.However,lactic acidemia induced by mefformin was reported in patients without renal dysfunction.It is unclear that whether lactatemia exists in diabetic patients with normal renal function in Chinese or not and its influencing factors.This study aimed to clarify the influencing factors of lactic acid,and identify a practiced clinical marker to predict the hyperlactacidemia in diabetics with normal renal function.Methods The clinical data and venous blood samples of 1024 type 2 diabetic patients treated with(n=426)or without metformin(n=599)were collected.The lactic acid was assayed by enzyme-electrode method.The biochemical indexes included creatinine(Cr)and hepatase were measured with enzymatic procedures.The lactic acid concentrations of different Cr subgroups were compared,and the correlation and receiver operating characteristic curve analysis were used.Results The mean lactic acid level and the proportion of hyperlactatemia of metformin group were significantly higher than that of non-metformin group(P<0.01),but no lactic acidosis was found in all patients.The correlation and multiple stepwise regression analysis indicated that the correlative factors of lactic acid in turn were Cr,metformin,alanine transferase(ALT),body mass index(BMI),Urine albumin(Ualb),and blood urea nitrogen(BUN)in total patients;and Cr,ALT,BMI and BUN in non-metformin treated patients;Cr and ALT in metformin-group.The lactate concentration increased with the increment of Cr levels,and reached its peak at Cr 111-130 μmol/L,and the optimal cutoff of Cr in predicting hyperlactacidemia was 96.5 μmol/L.Conclusions Metformin can increase the incidence of lactatemia in type 2 diabetic patients without renal dysfunction.Cr,ALT,and BMI are independent associated factors of blood lactic acid levels.There is low proportion of lactatemia in

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

    Directory of Open Access Journals (Sweden)

    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

  1. Enhancement and modeling of microparticle-added Rhizopus oryzae lactic acid production.

    Science.gov (United States)

    Coban, Hasan Bugra; Demirci, Ali

    2016-02-01

    Lactic acid has a wide industrial application area and can be produced by fungal strains. However, excessive bulk growth form of fungi during the fermentations is a major problem, which limits the fermentation performance. Microparticles are excellent tools to prevent bulk fungal growth and provide homogenized fermentation broth to increase uniformity and the prediction performance of the models. Therefore, in this study, addition of aluminum oxide and talcum microparticles into fermentations was evaluated to enhance the production of lactic acid by Rhizopus oryzae. The results showed that the bulk fungal growth was prevented and the lactic acid concentration increased from 6.02 to 13.88 and 24.01 g/L, when 15 g/L of aluminum oxide or 10 g/L of talcum was used, respectively, in the shake-flask fermentations. Additionally, substrate concentration, pH, and agitation were optimized in the bioreactors using response surface methodology, and optimum values were determined as 126 g/L of glucose, 6.22 pH, and 387 rpm, respectively. Under these conditions, lactic acid production further increased to 75.1 ± 1.5 g/L with 10 g/L of talcum addition. Also, lactic acid production and glucose consumption in the batch fermentation were successfully modeled with modified Gompertz model and modified logistic model. RMSE and MAE values for lactic acid production were calculated as 2.279 and 1.498 for the modified Gompertz model; 3.6 and 4.056 for the modified logistic model. Additionally, modified logistic model predicted glucose consumption with -2.088 MAE and 2.868 RMSE, whereas these values were calculated as 2.035 and 3.946 for the modified Gompertz model.

  2. 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.

  3. Use of autochthonous lactic acid bacteria starters to ferment mango juice for promoting its probiotic roles.

    Science.gov (United States)

    Liao, Xue-Yi; Guo, Li-Qiong; Ye, Zhi-Wei; Qiu, Ling-Yan; Gu, Feng-Wei; Lin, Jun-Fang

    2016-05-18

    Strains of Leuconostoc mesenteroides, Pediococcus pentosaceus, and Lactobacillus brevis were identified from mango fruits by partial 16S rDNA gene sequence. Based on the ability of producing mannitol and diacetyl, Leuconostoc mesenteroides MPL18 and MPL39 were selected within the lactic acid bacteria isolates, and used as mixed starters to ferment mango juice (MJ). Both the autochthonous strains grew well in fermented mango juice (FMJ) and remained viable at 9.81 log cfu mL(-1) during 30 days of storage at 4°C. The content of total sugar of FMJ was lower than that of MJ, while the concentration of mannitol was higher than that of MJ, and the concentration of diacetyl was 3.29 ± 0.12 mg L(-1). Among detected organic acids including citric acid, gallic acid, lactic acid, and acetic acid, only citric acid and gallic acid were found in MJ, while all detected organic acids were found in FMJ. The concentration of lactic acid of FMJ was the highest (78.62 ± 13.66 mM) among all detected organic acids. The DPPH radical scavenging capacity of FMJ was higher than that of MJ. Total phenolic compounds were better preserved in FMJ. The acidity and sweetness had a noticeable impact on the overall acceptance of the treated sample.

  4. Direct lactic acid fermentation of Jerusalem artichoke tuber extract using Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis.

    Science.gov (United States)

    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.

  5. Synergistic Extraction of Lactic Acid with Tri-n-Octylamine and Try-n-Butylphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Michiaki.; Yuba, Seiji.; Kondo, Kazuo. [Doshisha University, Department of Chemical Engineering and Materials Science (Japan)

    1998-12-01

    Synergistic extraction system of lactic acid is examined to develop to in situ extractive fermentation process. The addition of try-n-butyl phosphate(TBP) to the extraction system of lactic acid(HA) with tri-n-actylamine(TOA) diluted by hexane causes a large synergism. Extraction reaction with the mixed extractant is interpreted quite well based on the formation of mixed complex, HA{center_dot}TOA{center_dot}2TBP. Though the addition of hexane solution containing TBP and TOA to the culture of Lactobacillus rhamnosus results in low lactate production, some lactate is produced. (author)

  6. Synergistic Extraction of Lactic Acid with Tri-n-Octylamine and Try-n-Butylphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Michiaki.; Yuba, Seiji.; Kondo, Kazuo. (Doshisha University, Department of Chemical Engineering and Materials Science (Japan))

    1998-12-01

    Synergistic extraction system of lactic acid is examined to develop to in situ extractive fermentation process. The addition of try-n-butyl phosphate(TBP) to the extraction system of lactic acid(HA) with tri-n-actylamine(TOA) diluted by hexane causes a large synergism. Extraction reaction with the mixed extractant is interpreted quite well based on the formation of mixed complex, HA[center dot]TOA[center dot]2TBP. Though the addition of hexane solution containing TBP and TOA to the culture of Lactobacillus rhamnosus results in low lactate production, some lactate is produced. (author)

  7. 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.

  8. Antimicrobial properties of lactic acid bacteria isolated from uruguayan artisan cheese

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. Effect of drying temperatures on physical characteristics of sorghum flour modified with lactic acid

    Science.gov (United States)

    Manuhara, G. J.; Amanto, B. S.; Astuti, T. A.

    2017-04-01

    Different drying temperatures produce different starch structure, while the remains of lactic acid in sorghum grain might continue starch modification during drying. The purpose of this study was to determine the effect of drying temperatures (40, 50, 60° C) on physical characteristics of sorghum flour modified with lactic acid. Higher drying temperatures produced sorghum flour, with higher viscosity and swelling power, but lower whiteness and solubility. Modified sorghum flour showed higher value than the unmodified flour at all characteristics. Infrared spectroscopy showed that modification shifted absorption peak from 1,334 cm-1 to 1,373 cm-1, but there was no difference between samples dried at different temperatures.

  11. Effect of lactic, acetic and citric acids on quality changes of refrigerated green mussel, Perna viridis (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    Payap Masniyom

    2007-07-01

    Full Text Available Effect of lactic, acetic and citric acids on the quality changes and shelf-life extension of green mussel stored at 4oC was investigated. The inhibitory effect on bacterial growth was pronounced when the concentration of lactic, acetic and citric acids increased (P<0.05. Green mussel dipped with lactic acid had the lower total volatile base, trimethylamine, ammonia and TCA-soluble peptides contents than those dipped in acetic and citric acids. However, the increases in exudates loss and cooking loss were observed in samples dipped in organic acids, causing the denaturation of muscle protein by acids used. Thiobarbituric acid reactive substances (TBARS increased as the organic acid concentration increased (P<0.05. Lactic acid dipped samples, particularly with 0.2 M, showed the greater acceptability than did those dipped in other acids throughout the storage of 27 days. The control sample had the acceptability only for 6 days of storage.

  12. 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

  13. [Determination of enantiomeric purity for lactic acid in fermentation broth by Rhizopus oryzae with high performance liquid chromatography].

    Science.gov (United States)

    Bai, D M; Zhao, X M; Hu, Z D

    2001-01-01

    A procedure for the resolution of DL-lactic acid and the determination of D-isomer ratio in L-lactic acid fermentation broth by Rhizopus oryzae is described. The effects of pH of mobile phase and concentration of chiral mobile phase additives on resolution of DL-lactic acid were investigated. The optical isomers of lactic acid were resolved by RP-HPLC with 2,3,6-tri-O-beta-cyclodextrin(TM-beta-CD) as a chiral mobile phase additive, and C18 column as stationary phase, and detected at wavelength 210 nm. The results showed that a correction factor should be introduced into the equation for calculation of the percentage of D-lactic acid, because the UV absorption of D-lactic acid and L-lactic acid might not be the same when TM-beta-CD was present. Quantitation was achieved with external standard method, the average recovery was 100.4%, and the relative standard deviation was 0.82%. This method can be used for the determination of the percentage of D-isomer in L-lactic acid fermentation broth by Rhizopus oryzae, and it is simple, rapid and accurate. The results showed that the mass fraction of D-isomer in the fermented broth increased during the period of storage.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Solid phase extraction of lactic acid from fermentation broth by anion-exchangeable silica confined ionic liquids.

    Science.gov (United States)

    Bi, Wentao; Zhou, Jun; Row, Kyung Ho

    2011-01-15

    Three anion-exchangeable, silica-confined ionic liquids were synthesized for solid phase extraction of lactic acid from fermentation broth, followed by high-performance liquid chromatography coupled to ultraviolet detection. By comparing the adsorption isotherms of lactic acid on different silica-confined ionic liquids, interactions between the lactic acid and sorbents were investigated. The adsorbed amounts were then fitted into different adsorption isotherm equations; finally, the Langmuir equation was selected. Then the imidazolium silica with the highest adsorption capacity of lactic acid was packed into a cartridge for solid phase extraction. The loading volume of the cartridge was optimized by the Langmuir equation and geometry. After washing with distilled water and eluting with 0.25 mol L(-1) of an HCl solution, the lactic acid was separated from interference with a recovery yield of 91.9%. Furthermore, this kind of anion-exchangeable material exhibited potential for industrial applications and separation of other anionic bioactive compounds.

  16. OBTAINING OF PROTEIC BIOMASS BY CULTIVATION OF LACTIC ACID BACTERIA ON GRAPE MARC DIFFUSION SOLUTION

    Directory of Open Access Journals (Sweden)

    Marian BUTU

    2013-08-01

    Full Text Available In this article are presented the researches made in order to obtain protein biomass with the aid of lactic bacteria grown on an economically medium, achieved by using secondary products from the winery: marc and wine yeast. Therefore, there were cultivated two strains of Lactobacillus sp. on five different growth medium. The protein biosynthesis and evolution of lactic fermentation were monitored by determining the optical density (OD of the culture at a wavelength λ = 600 nm and by counting the colony forming units (CFU by serial dilutions and seeding on plates and by determination of lactic acid obtained. The results showed that the fermentation medium represented by diffusion solution of the marc, enriched with peptone is economically profitable compared to other culture media containing peptone, yeast extract, glucose, minerals, amino acids and vitamins presented in the literature.

  17. In vitro Degradation of Butanediamine-Grafted Poly(DL-Lactic acids)

    Institute of Scientific and Technical Information of China (English)

    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.

  18. 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.

  19. New polymer of lactic-co-glycolic acid-modified polyethylenimine for nucleic acid delivery.

    Science.gov (United States)

    Lü, Jian-Ming; Liang, Zhengdong; Wang, Xiaoxiao; Gu, Jianhua; Yao, Qizhi; Chen, Changyi

    2016-08-01

    To develop an improved delivery system for nucleic acids. We designed, synthesized and characterized a new polymer of lactic-co-glycolic acid-modified polyethylenimine (LGA-PEI). Functions of LGA-PEI polymer were determined. The new LGA-PEI polymer spontaneously formed nanoparticles (NPs) with DNA or RNA, and showed higher DNA or RNA loading efficiency, higher or comparable transfection efficacy, and lower cytotoxicity in several cell types including PANC-1, Jurkat and HEK293 cells, when compared with lipofectamine 2000, branched or linear PEI (25 kDa). In nude mouse models, LGA-PEI showed higher delivery efficiency of plasmid DNA or miRNA mimic into pancreatic and ovarian xenograft tumors. LGA-PEI/DNA NPs showed much lower toxicity than control PEI NPs in mouse models. The new LGA-PEI polymer is a safer and more effective system to deliver DNA or RNA than PEI.

  20. Distribution of D-amino acids in vinegars and involvement of lactic acid bacteria in the production of D-amino acids.

    Science.gov (United States)

    Mutaguchi, Yuta; Ohmori, Taketo; Akano, Hirofumi; Doi, Katsumi; Ohshima, Toshihisa

    2013-01-01

    Levels of free D-amino acids were compared in 11 vinegars produced from different sources or through different manufacturing processes. To analyze the D- and L-amino acids, the enantiomers were initially converted into diastereomers using pre-column derivatization with o-phthaldialdehyde plus N-acethyl-L-cysteine or N-tert-butyloxycarbonyl-L-cysteine. This was followed by separation of the resultant fluorescent isoindol derivatives on an octadecylsilyl stationary phase using ultra-performance liquid chromatography. The analyses showed that the total D-amino acid level in lactic fermented tomato vinegar was very high. Furthermore, analysis of the amino acids in tomato juice samples collected after alcoholic, lactic and acetic fermentation during the production of lactic fermented tomato vinegar showed clearly that lactic fermentation is responsible for the D-amino acids production; marked increases in D-amino acids were seen during lactic fermentation, but not during alcoholic or acetic fermentation. This suggests lactic acid bacteria have a greater ability to produce D-amino acids than yeast or acetic acid bacteria.

  1. Purification of Lactic Acid by Heterogeneous Catalytic Distillation Using Ion-exchange Resins

    Institute of Scientific and Technical Information of China (English)

    马利; 张阳; 杨基础

    2005-01-01

    The purification of lactic acid based on the esterification of raw lactic acid from fermentation broth and then the catalytic distillation hydrolysis of methyl lactate simultaneously to achieve pure lactic acid is reported. The esterification kinetics of lactic acid with methanol catalyzed by strong-acid cation-exchange resins (Amberlyst-15,D001, D002, NKC, 002) was studied under the condition that simulates the real catalytic environment. Experimental results were correlated by a Langmuir-Hinselwood model and the nonideality of the solution was taken into account by using activities calculated by the universal quasichemical functional group activity coefficient (UNIFAC) method.A good agreement between the model and the experimental data was achieved. Continuous purification experiments were conducted to find the optimum column configuration and operation condition for the system. The effects of various parameters, e.g. the length of different section of the column, feed rate and ratio of reactants, packing material and catalyst type, were studied. This novel system shows good separation results in lab scale, and is potential for industrial application.

  2. Poly-lactic acid synthesis for application in biomedical devices - a review.

    Science.gov (United States)

    Lasprilla, Astrid J R; Martinez, Guillermo A R; Lunelli, Betânia H; Jardini, André L; Filho, Rubens Maciel

    2012-01-01

    Bioabsorbable polymers are considered a suitable alternative to the improvement and development of numerous applications in medicine. Poly-lactic acid (PLA,) is one of the most promising biopolymers due to the fact that the monomers may produced from non toxic renewable feedstock as well as is naturally occurring organic acid. Lactic acid can be made by fermentation of sugars obtained from renewable resources as such sugarcane. Therefore, PLA is an eco-friendly product with better features for use in the human body (nontoxicity). Lactic acid polymers can be synthesized by different processes so as to obtain products with an ample variety of chemical and mechanical properties. Due to their excellent biocompatibility and mechanical properties, PLA and their copolymers are becoming widely used in tissue engineering for function restoration of impaired tissues. In order to maximize the benefits of its use, it is necessary to understand the relationship between PLA material properties, the manufacturing process and the final product with desired characteristics. In this paper, the lactic acid production by fermentation and the polymer synthesis such biomaterial are reviewed. The paper intends to contribute to the critical knowledge and development of suitable use of PLA for biomedical applications. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Synthesis of the Biomimetic Polymer: Aliphatic Diamine and RGDS Modified Poly(d,l-lactic acid)

    Institute of Scientific and Technical Information of China (English)

    Xu Feng NIU; Yuan Liang WANG; Yan Feng LUO; Jun PAN; Juan Fang SHANG; Li Xia GUO

    2005-01-01

    A novel poly(d,l-lactic acid) (PDLLA) based biomimetic polymer was synthesized by grafting maleic anhydride, butanediamine and arg-gly-asp-ser (RGDS) peptides onto the backbone of PDLLA, aiming to overcome the acidity and auto-accelerating degradation of PDLLA during degradation and to improve its biospecificity and biocompatibility. The synthetic copolymer was characterized by FTIR, 13C NMR and amino acid analyzer (AAA).

  4. Effect of L-lactic acid on calcium absorption in rats fed omeprazole.

    Science.gov (United States)

    Chonan, O; Takahashi, R; Yasui, H; Watanuki, M

    1998-06-01

    We examined the effect of L-lactic acid on calcium absorption in male Wistar rats made achlorhydric by dietary omeprazole, a proton pump inhibitor. The dietary omeprazole intake (0.03 g/100 g of diet) increased the gastric pH and decreased the apparent calcium absorption ratio. Dietary famotidine (0.03 g/100 g of diet), an H2-receptor antagonist, and lower doses of omeprazole (0.005 or 0.01 g/100 g of diet) did not affect the gastric pH or the calcium absorption. In a second experiment, dietary lactic acid (0.5, 1.0, or 2.5 g/100 g of diet) increased the intestinal calcium absorption dose dependently in rats fed omeprazole (0.03 g/100 g of diet). The gastric pH was significantly decreased only in the rats fed higher doses of lactic acid (1.0, or 2.5 g/100 g of diet). In a third experiment, a dietary sour milk beverage containing lactic acid (0.5 g/100 g of diet) increased the intestinal calcium absorption, but did not affect the gastric pH in rats fed omeprazole (0.03 g/100 g of diet). Although the significance of gastric acid in terms of overall calcium absorption is not known, under the present experimental conditions, the inhibition of gastric acid secretion by dietary omeprazole decreased the apparent calcium absorption, and the dietary lactic acid prevented the calcium absorption in rats fed omeprazole.

  5. Sandwich-Architectured Poly(lactic acid)-Graphene Composite Food Packaging Films

    NARCIS (Netherlands)

    Goh, Kunli; Heising, Jenneke K.; Yuan, Yang; Karahan, Huseyin E.; Wei, Li; Zhai, Shengli; Koh, Jia Xuan; Htin, Nanda M.; Zhang, Feimo; Wang, Rong; Fane, Anthony G.; Dekker, Matthijs; Dehghani, Fariba; Chen, Yuan

    2016-01-01

    Biodegradable food packaging promises a more sustainable future. Among the many different biopolymers used, poly(lactic acid) (PLA) possesses the good mechanical property and cost-effectiveness necessary of a biodegradable food packaging. However, PLA food packaging suffers from poor water vapor

  6. Nanocomposites from lignin-containing cellulose nanocrystals and poly(lactic acid)

    Science.gov (United States)

    Liqing Wei; Umesh Agarwal; Nicole Stark; Ronald Sabo

    2017-01-01

    Utilizing lignin-containing cellulose nanocrystals (HLCNCs) as reinforcing agents to poly(lactic acid) (PLA) for nanocomposites was studied for the first time. The PLA/HLCNCs nanocomposites were prepared by extrusion and injecting molding. The freeze-dried HLCNCs showed micron scale agglomerates. As indicated by the water contact angle measurements, the HLCNCs were...

  7. Competitive selection of lactic acid bacteria that persist in the human oral cavity

    NARCIS (Netherlands)

    Snel, J.; Marco, M.L.; Kingma, F.; Noordman, W.M.; Rademaker, J.; Kleerebezem, M.

    2011-01-01

    Lactic acid bacteria (LAB) might offer opportunities as oral probiotics provided candidate strains persist in the mouth. After intake of a mixture of 69 LAB, strains of Lactobacillus fermentum and Lactobacillus salivarius were especially recovered. Coaggregation with other microbes is likely not a p

  8. Engineering of thermotolerant Bacillus coagulans for production of D(-)-lactic acid

    Science.gov (United States)

    Wang, Qingzhao; Shanmugam, Keelnatham T; Ingram, Lonnie O

    2014-12-02

    Genetically modified microorganisms having the ability to produce D(-)-lactic acid at temperatures between 30.degree. C. and 55.degree. C. are provided. In various embodiments, the microorganisms may have the chromosomal lactate dehydrogenase (ldh) gene and/or the chromosomal acetolactate synthase (alsS) gene inactivated. Exemplary microorganisms for use in the disclosed methods are Bacillus spp., such as Bacillus coagulans.

  9. Perspectives on the contribution of lactic acid bacteria to cheese flavor development

    NARCIS (Netherlands)

    Steele, James; Broadbent, Jeffery; Kok, Jan

    It has been known since the 1960s that lactic acid bacteria are essential for the development of cheese flavor. In the ensuing 50 years significant research has been directed at understanding the microbiology, genetics and biochemistry of this process. This review briefly covers the current status

  10. Intensification of enzymatic conversion of glucose to lactic acid by reactive extraction

    NARCIS (Netherlands)

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

    2003-01-01

    Lactic acid is an important commercial product and extracting this 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)

  11. Survival and growth of probiotic lactic acid bacteria in refrigerated pickle products

    Science.gov (United States)

    We examined 10 lactic acid bacteria that have been previously characterized for commercial use as probiotic cultures, mostly for dairy products, including 1 Pediococcus and 9 Lactobacilli. Our objectives were to develop a rapid procedure for determining the long-term survivability of these cultures ...

  12. Glucansucrases from lactic acid bacteria which produce water-insoluble polysaccharides from sucrose

    Science.gov (United States)

    Dextrans and related glucans produced from sucrose by lactic acid bacteria have been studied for many years and are used in numerous commercial applications and products. Most of these glucans are water-soluble, except for a few notable exceptions from cariogenic Streptococcus spp. and a very small ...

  13. Distinct gut-derived lactic acid bacteria elicit divergent dendritic cell-mediated NK cell responses

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen; Zeuthen, Louise Hjerrild; Christensen, Hanne

    2007-01-01

    Lactic acid bacteria (LAB) are abundant in the gastrointestinal tract where they continuously regulate the immune system. NK cells are potently activated by dendritic cells (DCs) matured by inflammatory stimuli, and NK cells are present in the gut epithelium and in mesenteric lymph nodes...

  14. Drivers for the establishment and composition of the sourdough lactic acid bacteria biota.

    Science.gov (United States)

    Gobbetti, Marco; Minervini, Fabio; Pontonio, Erica; Di Cagno, Raffaella; De Angelis, Maria

    2016-12-19

    The drivers for the establishment and composition of the sourdough microbiota, with particular emphasis on lactic acid bacteria, are reviewed and discussed. More than 60 different species of lactobacilli were identified from sourdoughs, showing the main overlapping between sourdough and human intestine ecosystems. The microbial kinetics during sourdough preparation was described by several studies using various methodological approaches, including culture-dependent and -independent (e.g., high throughput sequencing), and metabolite and meta-transcriptome analyses. Although the abundant microbial diversity harbored by flours, a succession of dominating and sub-dominating populations of lactic acid bacteria suddenly occurred during sourdough propagation, leading to the progressive assembly of the bacterial community. The contribution of all the potential sources (house microbiota, flour, types of flours and additional ingredients) for contaminating lactic acid bacteria was compared with the aim to find overlapping or specific routes that affect the sourdough microbiota. Once established and mature, pros and cons regarding the stability of the sourdough lactic acid bacteria biota were also reviewed, showing contradictory results, which were mainly dependent on the species/strains. Probably, the future research efforts should be dedicated to decrease the sources/drivers of noticeable variation rather than to full standardization of the process for sourdough preparation and use.

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

    African Journals Online (AJOL)

    STORAGESEVER

    2009-01-05

    Jan 5, 2009 ... highest lactic acid production (20.8 g/l) and rate of productivity (0.304 g/l.h) was achieved when the volume percent ..... tation cannot utilize the high feed (sugar) concentration, and whey without ... in continuous fermentation.

  16. Reactive extraction of lactic acid using alamine 336 in MIBK : equilibria and kinetics

    NARCIS (Netherlands)

    Wasewar, Kailas L.; Heesink, A. Bert M.; Versteeg, Geert F.; 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) sy

  17. Inducible gene expression and environmentally regulated genes in lactic acid bacteria

    NARCIS (Netherlands)

    Kok, Jan

    1996-01-01

    Relatively recently, a number of genes and operons have been identified in lactic acid bacteria that are inducible and respond to environmental factors. Some of these genes/operons had been isolated and analysed because of their importance in the fermentation industry and, consequently, their transc

  18. TECHNOLOGICAL AND FUNCTIONAL PROPERTIES OF LACTIC ACID BACTERIA: THE IMPORTANCE OF THESE MICROORGANISMS FOR FOOD

    Directory of Open Access Journals (Sweden)

    Amanda de Souza Motta

    2015-12-01

    Full Text Available Eacters of coccus or rods Gram-positive, catalase negative, non-sporulating, which produce lactic acid as the major end product during the fermentation of carbohydrates. When applied on food, provides beneficial effects to consumers through its functional and technological properties. With this the present review article, explore the potential application of lactic acid bacteria in food. The following genera are considered the principal lactic acid bacteria: Aerococcus, Carnobacterium, Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Oenococcus, Pediococcus, Streptococcus, Tetragenococcus, Vagococcus and Weissella. These cultures have been used as starter or adjunct cultures for the fermentation of foods and beverages due to their contributions to the sensorial characteristics of these products and by microbiological stability. Their probiotic properties have also been investigated. More recent studies by indigenous cultures have received increased attention in light of the search for isolated cultures of a given raw material and a certain region. These microorganisms are being investigated for its functional and technological potential that may be applied in product development with its own characteristics and designation of origin. Those properties will be discussed in the present review in order to highlight the performance of these bacteria and the high degree of control over the fermentation process and standardization of the final product. The use of autochthonous cultures will be considered due the increase of studies of new cultures of lactic acid bacteria isolated of milk and meat of distinct products.

  19. Diversity, vitality and activities of intestinal lactic acid bacteria and bifidobacteria assessed by molecular approaches

    NARCIS (Netherlands)

    Vaughan, E.E.; Heilig, G.H.J.; Ben-Amor, K.; Vos, de W.M.

    2005-01-01

    While lactic acid bacteria and bifidobacteria have been scientifically important for over a century, many of these are marketed today as probiotics and have become a valuable and rapidly expanding sector of the food market that is leading functional foods in many countries. The human

  20. Multiple Genome Sequences of Important Beer-Spoiling Lactic Acid Bacteria

    OpenAIRE

    Geissler, Andreas J.; Behr, Jürgen; Vogel, Rudi F.

    2016-01-01

    Seven strains of important beer-spoiling lactic acid bacteria were sequenced using single-molecule real-time sequencing. Complete genomes were obtained for strains of Lactobacillus paracollinoides, Lactobacillus lindneri, and Pediococcus claussenii. The analysis of these genomes emphasizes the role of plasmids as the genomic foundation of beer-spoiling ability.