Antibacterial Activity of Lactic Acid Bacteria Isolated from Gastrointestinal Tract of “Ayam Kampung” Chicken Against Food Pathogens

Science.gov (United States)

Nur Jannah, Siti; Rini Saraswati, Tyas; Handayani, Dwi; Pujiyanto, Sri

2018-05-01

Food borne disease results from ingestion of water and wide variety of food contaminated with pathogenic organisms. The main causes of food borne diseases are bacteria, such as Escherichia coli and Staphylococcus aureus. The objective of this study was to determine antimicrobial activity of lactic acid bacteria (LAB) isolated from local chicken gastrointestinal tract with an emphasis on their probiotic properties. The colonies of bacteria that producing clear zone on MRSA plus 0.5% CaCO3, Gram-positive and catalase-negative were isolated as lactic acid bacteria. Some of the strains (10 isolates) were tested for their ability to inhibit growth of Escherichia coli and Staphylococcus aureus, and for acid pH and bile salt tolerance. The results showed that the all selected isolates producing antimicrobial compounds inhibits the growth of Escherichia coli and Staphylococcus aureus, both in the supernatant and supernatant plus 2M NaOH, and still growing in medium condition with pH 2.0 and 0.1% bile salt. It revealing the potential use of the lactic acid bacteria from chicken gastrointestinal tract for probiotics in food.

ISOLATION AND IDENTIFICATION OF LACTIC ACID PRODUCING BACTERIA FROM CAMEL MILK

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

2002-03-01

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

TECHNOLOGICAL AND FUNCTIONAL PROPERTIES OF LACTIC ACID BACTERIA: THE IMPORTANCE OF THESE MICROORGANISMS FOR FOOD

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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.

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

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

Wu, Chongde; Huang, Jun; Zhou, Rongqing

2014-07-04

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

21 CFR 184.1061 - Lactic acid.

Science.gov (United States)

2010-04-01

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

[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.

Antimicrobial Activity and Antibiotic Sensitivity of Three Isolates of Lactic Acid Bacteria From Fermented Fish Product, Budu

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Liasi, S. A.

2009-01-01

Full Text Available Three isolates of lactic acid bacteria (LAB from the fermented food product, Budu, were identified as genus lactobacillus (Lactobacillus casei LA17, Lactobacillus plantarum LA22 and L. paracasei LA02, and the highest population was Lb. paracasei LA02. The antibacterial agent produced by the isolates inhibited the growth of a range of gram-positive and gram-negative microorganisms. Antimicrobial sensitivity test to 18 different types of antibiotic were evaluated using the disc diffusion method. Inhibition zone diameter was measured and calculated from the means of five determinations and expressed in terms of resistance or susceptibility. All the LAB isolates were resistant to colestin sulphate, streptomycin, amikacin, norfloxacin, nalidixic acid, mecillinam, sulphanethoxazole/ trimethoprim, kanamycin, neomycin, bacitracin and gentamycin but susceptible to erythromycin, penicillin G, chloramphenicol, tetracycline, ampicillin and nitrofurantion.

Phylogenetic Diversity of Lactic Acid Bacteria Associated with Paddy Rice Silage as Determined by 16S Ribosomal DNA Analysis

OpenAIRE

Ennahar, Saïd; Cai, Yimin; Fujita, Yasuhito

2003-01-01

A total of 161 low-G+C-content gram-positive bacteria isolated from whole-crop paddy rice silage were classified and subjected to phenotypic and genetic analyses. Based on morphological and biochemical characters, these presumptive lactic acid bacterium (LAB) isolates were divided into 10 groups that included members of the genera Enterococcus, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Weissella. Analysis of the 16S ribosomal DNA (rDNA) was used to confirm the presence of the ...

21 CFR 862.1450 - Lactic acid test system.

Science.gov (United States)

2010-04-01

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

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.

Identification of lactic acid bacteria isolated from Tarhana, a traditional Turkish fermented food

DEFF Research Database (Denmark)

Sengun, Ilkin Yucel; Nielsen, Dennis Sandris; Karapinar, Mehmet

2009-01-01

Tarhana is a traditional fermented product produced from a mixture of spontaneously fermented yogurt and wheat flour in Turkey. The aims of the present study were to enumerate and identify for the first time by molecular biology-based methods predominant lactic acid bacteria (LAB) isolated during...... processing of Tarhana. Samples were collected from eight different regions of Turkey. In order to explore the relationship between raw material and the microbiology of Tarhana, yogurt and wheat flour were also analyzed. A total of 226 Gram-positive and catalase-negative isolates were obtained from MRS, M17...... and S. thermophilus was found to be the yogurt....

21 CFR 582.1061 - Lactic acid.

Science.gov (United States)

2010-04-01

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

Process for the preparation of lactic acid and glyceric acid

Science.gov (United States)

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

2008-12-02

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

Current status and emerging role of glutathione in food grade lactic acid bacteria

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Pophaly Sarang

2012-08-01

Full Text Available Abstract Lactic acid bacteria (LAB have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms.

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

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Ke Xu

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

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

Science.gov (United States)

Xu, Ke; Xu, Ping

2014-01-01

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

Identification of lactic acid bacteria from spoilage associations of cooked and brined shrimps stored under modified atmosphere between 0 degrees C and 25 degrees C

DEFF Research Database (Denmark)

Dalgaard, Paw; Vancanneyt, M.; Vilalta, N.E.

2003-01-01

MAP shrimps were characterized by phenotypic tests and identified as lactic acid bacteria (78 isolates), other Gram-positive bacteria (13 isolates) and Gram-negative bacteria (11 isolates). A selection of 48 LAB isolates were further characterized and identified by phenotypic tests and SDS-PAGE...... the dominant parts of spoilage associations of cooked and brined MAP shrimps stored at high and low temperatures, respectively. Significance and Impact of the Study: The SDS-PAGE technique and simple biochemical keys allowed the majority of LAB isolates from spoilage associations of cooked and brined MAP...

Antiadhesion agents against Gram-positive pathogens.

Science.gov (United States)

Cascioferro, Stella; Cusimano, Maria Grazia; Schillaci, Domenico

2014-01-01

A fundamental step of Gram-positive pathogenesis is the bacterial adhesion to the host tissue involving interaction between bacterial surface molecules and host ligands. This review is focused on antivirulence compounds that target Gram-positive adhesins and on their potential development as therapeutic agents alternative or complementary to conventional antibiotics in the contrast of pathogens. In particular, compounds that target the sortase A, wall theicoic acid inhibitors, carbohydrates able to bind bacterial proteins and proteins capable of influencing the bacterial adhesion, were described. We further discuss the advantages and disadvantages of this strategy in the development of novel antimicrobials and the future perspective of this research field still at its first steps.

Biotechnological Production of Lactic Acid and Its Recent Applications

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Young-Jung Wee

2006-01-01

Full Text Available Lactic acid is widely used in the food, cosmetic, pharmaceutical, and chemical industries and has received increased attention for use as a monomer for the production of biodegradable poly(lactic acid. It can be produced by either biotechnological fermentation or chemical synthesis, but the former route has received considerable interest recently, due to environmental concerns and the limited nature of petrochemical feedstocks. There have been various attempts to produce lactic acid efficiently from inexpensive raw materials. We present a review of lactic acid-producing microorganisms, raw materials for lactic acid production, fermentation approaches for lactic acid production, and various applications of lactic acid, with a particular focus on recent investigations. In addition, the future potentials and economic impacts of lactic acid are discussed.

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.

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

OpenAIRE

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

2005-01-01

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

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

Science.gov (United States)

Yang, Jinsong; Tan, Haisheng; Cai, Yimin

2016-07-01

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

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

DEFF Research Database (Denmark)

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

1998-01-01

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

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

International Nuclear Information System (INIS)

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

1980-01-01

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

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...

Identification and characterization of probiotic lactic acid bacteria isolated from traditional persian pickled vegetables

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Soltan Dallal, M.M.

2017-09-01

Full Text Available Background: The pickle, a traditional fermented product, is popular among Iranians. Much research has been conducted worldwide on this food group. Due to a lack of related data in Iran, this study was conducted to isolate and identify dominant lactic acid bacteria (LAB in pickles and salted pickles.Materials and methods: Seventy samples were collected from different regions of Iran. The isolated bacteria were identified as LAB by Gram staining and catalase by using MRS agar. Then, those strains were identified at the species level by physiological tests (e.g., gas production from glucose, arginine hydrolysis, CO production from glucose in MRS broth, carbohydrate fermentation and growth at temperatures of 15°C, 30°C, and 45°C in MRS broth for 3 days. The probiotic characteristics of these bacteria were studied using acid and bile tolerance. The corresponding results were verified using PCR analyses of the 16S rDNA region. Results: 114 presumptive lactic acid bacteria (LAB with Gram-positive and catalase-negative properties were obtained from the samples. The results revealed that all isolated bacteria were identfied as ,, , , and. The predominant LAB in these pickles was which was isolated from most of the samples. Among the 114 LAB, 7 isolated species have probiotic potential. Six out of seven were recognized as and one remained unidentifiable by biochemical testing. PCR analysis and sequencing of the 16S rDNA region using 27f and 1522r primers showed that all of the probiotic strains were .Conclusion: The results of this study showed that the dominant LAB in traditional Persian pickled vegetables are , , , and . Moreover, was recognized as a probiotic species in pickled vegetables. The raw data obtained from this study can be used in the pickling industry to improve the nutritional value of products.

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

Science.gov (United States)

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

2012-04-01

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

Significant thermal energy reduction in lactic acid production process

International Nuclear Information System (INIS)

Mujtaba, Iqbal M.; Edreder, Elmahboub A.; Emtir, Mansour

2012-01-01

Lactic acid is widely used as a raw material for the production of biodegradable polymers and in food, chemical and pharmaceutical industries. The global market for lactic acid is expected to reach 259 thousand metric tons by the year 2012. For batch production of lactic acid, the traditional process includes the following steps: (i) esterification of impure lactic acid with methanol in a batch reactor to obtain methyl lactate (ester), (ii) separation of the ester in a batch distillation, (iii) hydrolysis of the ester with water in a batch reactor to produce lactic acid and (iv) separation of lactic acid (in high purity) in a batch distillation. Batch reactive distillation combines the benefit of both batch reactor and batch distillation and enhances conversion and productivity (Taylor and Krishna, 2000 ; Mujtaba and Macchietto, 1997 ). Therefore, the first and the last two steps of the lactic acid production process can be combined together in batch reactive distillation () processes. However, distillation (batch or continuous) is an energy intensive process and consumes large amount of thermal energy (via steam). This paper highlights how significant (over 50%) reduction in thermal energy consumption can be achieved for lactic acid production process by carefully controlling the reflux ratio but without compromising the product specification. In this paper, only the simultaneous hydrolysis of methyl lactate ester and the separation of lactic acid using batch reactive distillation is considered.

Selection of lactic acid bacteria able to ferment inulin hydrolysates

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Octavian BASTON

2012-12-01

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

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

OpenAIRE

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

2013-01-01

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

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

Science.gov (United States)

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

2005-10-01

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

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...

The possibility of lactic acid fermentation in the triticale stillage

Directory of Open Access Journals (Sweden)

MILICA MARKOVIĆ

2011-06-01

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

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

Selenoproteins in Archaea and Gram-positive bacteria.

Science.gov (United States)

Stock, Tilmann; Rother, Michael

2009-11-01

Selenium is an essential trace element for many organisms by serving important catalytic roles in the form of the 21st co-translationally inserted amino acid selenocysteine. It is mostly found in redox-active proteins in members of all three domains of life and analysis of the ever-increasing number of genome sequences has facilitated identification of the encoded selenoproteins. Available data from biochemical, sequence, and structure analyses indicate that Gram-positive bacteria synthesize and incorporate selenocysteine via the same pathway as enterobacteria. However, recent in vivo studies indicate that selenocysteine-decoding is much less stringent in Gram-positive bacteria than in Escherichia coli. For years, knowledge about the pathway of selenocysteine synthesis in Archaea and Eukarya was only fragmentary, but genetic and biochemical studies guided by analysis of genome sequences of Sec-encoding archaea has not only led to the characterization of the pathways but has also shown that they are principally identical. This review summarizes current knowledge about the metabolic pathways of Archaea and Gram-positive bacteria where selenium is involved, about the known selenoproteins, and about the respective pathways employed in selenoprotein synthesis.

Lactic acid production from xylose by Geobacillus stearothermophilus strain 15

Science.gov (United States)

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

2017-09-01

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

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

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

African Journals Online (AJOL)

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

Procalcitonin levels in gram-positive, gram-negative, and fungal bloodstream infections.

Science.gov (United States)

Leli, Christian; Ferranti, Marta; Moretti, Amedeo; Al Dhahab, Zainab Salim; Cenci, Elio; Mencacci, Antonella

2015-01-01

Procalcitonin (PCT) can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR) 3.4-44.1) bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6-7.6) or fungal (0.5 ng/mL, IQR 0.4-1) infections (P Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919-0.969, P Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9-48.5 versus 3.5 ng/mL, IQR 0.8-21.5; P Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

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

Lactic acid Production with in situ Extraction in Membrane Bioreactor

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Hamidreza Ghafouri Taleghani

2017-01-01

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

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

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Alejandra Plata Pinzón

2012-10-01

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

Lactic acid fermentation from refectory waste: Factorial design analysis

African Journals Online (AJOL)

Yomi

2012-04-12

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

Cellular reprogramming by gram-positive bacterial components: a review.

LENUS (Irish Health Repository)

Buckley, Julliette M

2012-02-03

LPS tolerance has been the focus of extensive scientific and clinical research over the last several decades in an attempt to elucidate the sequence of changes that occur at a molecular level in tolerized cells. Tolerance to components of gram-positive bacterial cell walls such as bacterial lipoprotein and lipoteichoic acid is a much lesser studied, although equally important, phenomenon. This review will focus on cellular reprogramming by gram-positive bacterial components and examines the alterations in cell surface receptor expression, changes in intracellular signaling, gene expression and cytokine production, and the phenomenon of cross-tolerance.

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

NARCIS (Netherlands)

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

2004-01-01

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

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

NARCIS (Netherlands)

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

2004-01-01

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

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

DEFF Research Database (Denmark)

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

2013-01-01

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

L-Lactic Acid Production by Lactobacillus rhamnosus ATCC 10863

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Ana Lívia Chemeli Senedese

2015-01-01

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

Gram-negative, but not Gram-positive, bacteria elicit strong PGE2 production in human monocytes.

Science.gov (United States)

Hessle, Christina C; Andersson, Bengt; Wold, Agnes E

2003-12-01

Gram-positive and Gram-negative bacteria induce different cytokine patterns in human mononuclear cells. We have seen that Gram-positives preferentially induce IL-12 and TNF-alpha, whereas Gram-negatives induce more IL-10, IL-6, and IL-8. In this study, we compared the capacity of these two groups of bacteria to induce PGE2. Monocytes stimulated with Gram-negative bacterial species induced much more PGE2 than did Gram-positive bacteria (5600 +/- 330 vs. 1700 +/- 670 pg/mL, p Gram-positive and Gram-negative bacteria. We suggest that Gram-positive and Gram-negative bacteria may stimulate different innate effector functions; Gram-positive bacteria promoting cell-mediated effector functions whereas Gram-negative bacteria inducing mediators inhibiting the same.

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

Science.gov (United States)

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

2016-10-01

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

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

Science.gov (United States)

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

2006-01-01

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

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

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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.

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

Science.gov (United States)

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

2012-07-01

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

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

NARCIS (Netherlands)

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

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

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.

Procalcitonin Levels in Gram-Positive, Gram-Negative, and Fungal Bloodstream Infections

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Christian Leli

2015-01-01

Full Text Available Procalcitonin (PCT can discriminate bacterial from viral systemic infections and true bacteremia from contaminated blood cultures. The aim of this study was to evaluate PCT diagnostic accuracy in discriminating Gram-positive, Gram-negative, and fungal bloodstream infections. A total of 1,949 samples from patients with suspected bloodstream infections were included in the study. Median PCT value in Gram-negative (13.8 ng/mL, interquartile range (IQR 3.4–44.1 bacteremias was significantly higher than in Gram-positive (2.1 ng/mL, IQR 0.6–7.6 or fungal (0.5 ng/mL, IQR 0.4–1 infections (P<0.0001. Receiver operating characteristic analysis showed an area under the curve (AUC for PCT of 0.765 (95% CI 0.725–0.805, P<0.0001 in discriminating Gram-negatives from Gram-positives at the best cut-off value of 10.8 ng/mL and an AUC of 0.944 (95% CI 0.919–0.969, P<0.0001 in discriminating Gram-negatives from fungi at the best cut-off of 1.6 ng/mL. Additional results showed a significant difference in median PCT values between Enterobacteriaceae and nonfermentative Gram-negative bacteria (17.1 ng/mL, IQR 5.9–48.5 versus 3.5 ng/mL, IQR 0.8–21.5; P<0.0001. This study suggests that PCT may be of value to distinguish Gram-negative from Gram-positive and fungal bloodstream infections. Nevertheless, its utility to predict different microorganisms needs to be assessed in further studies.

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

Science.gov (United States)

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

2017-11-25

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

Batch fermentative production of lactic acid from green- sugarcane juices

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Liliana Serna Cock

2004-07-01

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

Adhesion Properties of Lactic Acid Bacteria on Intestinal Mucin

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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.

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

International Nuclear Information System (INIS)

Murillo Viera, Esteban

2013-01-01

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

Lactic acid 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.

Lactic acid fermentation of cassava dough into agbelima.

Science.gov (United States)

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

1996-08-01

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

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.

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.

The impact of lactic acid bacteria on sourdough fermentation

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Savić Dragiša S.

2005-01-01

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

Exploitation of vegetables and fruits through lactic acid fermentation.

Science.gov (United States)

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

2013-02-01

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

9th International Symposium on Lactic Acid Bacteria

NARCIS (Netherlands)

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

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

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

African Journals Online (AJOL)

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

Antibacterial efficacy of triple-layered poly(lactic-co-glycolic acid)/nanoapatite/lauric acid guided bone regeneration membrane on periodontal bacteria.

Science.gov (United States)

Saarani, Nur Najiha; Jamuna-Thevi, Kalitheerta; Shahab, Neelam; Hermawan, Hendra; Saidin, Syafiqah

2017-05-31

A guided bone regeneration (GBR) membrane has been extensively used in the repair and regeneration of damaged periodontal tissues. One of the main challenges of GBR restoration is bacterial colonization on the membrane, constitutes to premature membrane degradation. Therefore, the purpose of this study was to investigate the antibacterial efficacy of triple-layered GBR membrane composed of poly(lactic-co-glycolic acid) (PLGA), nanoapatite (NAp) and lauric acid (LA) with two types of Gram-negative periodontal bacteria, Fusobacterium nucleatum and Porphyromonas gingivalis through a disc diffusion and bacterial count tests. The membranes exhibited a pattern of growth inhibition and killing effect against both bacteria. The increase in LA concentration tended to increase the bactericidal activities which indicated by higher diameter of inhibition zone and higher antibacterial percentage. It is shown that the incorporation of LA into the GBR membrane has retarded the growth and proliferation of Gram-negative periodontal bacteria for the treatment of periodontal disease.

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

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Sung-Soo Jang

2013-01-01

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

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

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Zhang, Yixing; Vadlani, Praveen V

2013-12-01

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

Heme and menaquinone induced electron transport in lactic acid bacteria

OpenAIRE

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

2009-01-01

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

Mechanocatalytic Production of Lactic Acid from Glucose by Ball Milling

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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.

Biodegradable poly(lactic acid)

Indian Academy of Sciences (India)

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

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

Science.gov (United States)

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

2015-10-01

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

Efficient Production of Lactic Acid from Sweet Sorghum Juice by a Newly Isolated Lactobacillus salivarius CGMCC 7.75.

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Liu, Quanlan; Wang, Shanglong; Zhi, Jian-Fei; Ming, Henglei; Teng, Dawei

2013-09-01

Sweet sorghum juice was a cheap and renewable resource, and also a potential carbon source for the fermentation production of lactic acid (LA) by a lactic acid bacterium. One newly isolated strain Lactobacillus salivarius CGMCC 7.75 showed the ability to produce the highest yield and optical purity of LA from sweet sorghum juice. Studies of feeding different concentrations of sweet sorghum juice and nitrogen source suggested the optimal concentrations of fermentation were 325 ml l(-1) and 20 g l(-1), respectively. This combination produced 142.49 g l(-1) LA with a productivity level of 0.90 g of LA per gram of sugars consumed. The results indicated the high LA concentration achieved using L. salivarius CGMCC 7.75 not only gives cheap industrial product, but also broaden the application of sweet sorghum.

Glycosaminoglycans are involved in pathogen adherence to corneal epithelial cells differently for Gram-positive and Gram-negative bacteria

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Beatriz García

2016-11-01

Full Text Available The epithelium of the cornea is continuously exposed to pathogens, and adhesion to epithelial cells is regarded as an essential first step in bacterial pathogenesis. In this article, the involvement of glycosaminoglycans in the adhesion of various pathogenic bacteria to corneal epithelial cells is analyzed. All microorganisms use glycosaminoglycans as receptors, but arranged in different patterns depending on the Gram-type of the bacterium. The heparan sulfate chains of syndecans are the main receptors, though other molecular species also seem to be involved, particularly in Gram-negative bacteria. Adherence is inhibited differentially by peptides, including heparin binding sequences, indicating the participation of various groups of Gram-positive and -negative adhesins. The length of the saccharides produces a major effect, and low molecular weight chains inhibit the binding of Gram-negative microorganisms but increase the adherence of Gram-positives. Pathogen adhesion appears to occur preferentially through sulfated domains, and is very dependent on N- and 6-O-sulfation of the glucosamine residue and, to a lesser extent, 2-O sulfation of uronic acid. These data show the differential use of corneal receptors, which could facilitate the development of new anti-infective strategies.

Cell immobilization for production of lactic acid biofilms do it naturally.

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Dagher, Suzanne F; Ragout, Alicia L; Siñeriz, Faustino; Bruno-Bárcena, José M

2010-01-01

Interest in natural cell immobilization or biofilms for lactic acid fermentation has developed considerably over the last few decades. Many studies report the benefits associated with biofilms as industrial methods for food production and for wastewater treatment, since the formation represents a protective means of microbial growth offering survival advantages to cells in toxic environments. The formation of biofilms is a natural process in which microbial cells adsorb to a support without chemicals or polymers that entrap the cells and is dependent on the reactor environment, microorganism, and characteristics of the support. These unique characteristics enable biofilms to cause chronic infections, disease, food spoilage, and devastating effects as in microbial corrosion. Their distinct resistance to toxicity, high biomass potential, and improved stability over cells in suspension make biofilms a good tool for improving the industrial economics of biological lactic acid production. Lactic acid bacteria and specific filamentous fungi are the main sources of biological lactic acid. Over the past two decades, studies have focused on improving the lactic acid volumetric productivity through reactor design development, new support materials, and improvements in microbial production strains. To illustrate the operational designs applied to the natural immobilization of lactic acid producing microorganisms, this chapter presents the results of a search for optimum parameters and how they are affected by the physical, chemical, and biological variables of the process. We will place particular emphasis upon the relationship between lactic acid productivity attained by various types of reactors, supports, media formulations, and lactic acid producing microorganisms. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Flow cytometric assessment of viability of lactic acid bacteria

NARCIS (Netherlands)

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

2001-01-01

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

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

African Journals Online (AJOL)

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

DEVELOPMENT OF VEGETABLE PUREES AND DRINKS BY LACTIC ACID FERMENTATION

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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.

Diagnosing periprosthetic infection: false-positive intraoperative Gram stains.

Science.gov (United States)

Oethinger, Margret; Warner, Debra K; Schindler, Susan A; Kobayashi, Hideo; Bauer, Thomas W

2011-04-01

Intraoperative Gram stains have a reported low sensitivity but high specificity when used to help diagnose periprosthetic infections. In early 2008, we recognized an unexpectedly high frequency of apparent false-positive Gram stains from revision arthroplasties. The purpose of this report is to describe the cause of these false-positive test results. We calculated the sensitivity and specificity of all intraoperative Gram stains submitted from revision arthroplasty cases during a 3-month interval using microbiologic cultures of the same samples as the gold standard. Methods of specimen harvesting, handling, transport, distribution, specimen processing including tissue grinding/macerating, Gram staining, and interpretation were studied. After a test modification, results of specimens were prospectively collected for a second 3-month interval, and the sensitivity and specificity of intraoperative Gram stains were calculated. The retrospective review of 269 Gram stains submitted from revision arthroplasties indicated historic sensitivity and specificity values of 23% and 92%, respectively. Systematic analysis of all steps of the procedure identified Gram-stained but nonviable bacteria in commercial broth reagents used as diluents for maceration of periprosthetic membranes before Gram staining and culture. Polymerase chain reaction and sequencing showed mixed bacterial DNA. Evaluation of 390 specimens after initiating standardized Millipore filtering of diluent fluid revealed a reduced number of positive Gram stains, yielding 9% sensitivity and 99% specificity. Clusters of false-positive Gram stains have been reported in other clinical conditions. They are apparently rare related to diagnosing periprosthetic infections but have severe consequences if used to guide treatment. Even occasional false-positive Gram stains should prompt review of laboratory methods. Our observations implicate dead bacteria in microbiologic reagents as potential sources of false-positive Gram

CHARACTERIZATION OF AUTOCHTHONUS LACTIC FLORA OF A CAMPANIAN CHILLI CHEESE PRODUCED FROM RAW SHEEP MILK

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A. Mormile

2012-08-01

Full Text Available The natural lactic flora of the artisanal chilli “Tramonti” cheese, a typical product manufactured in the “Lattari mountains”, area of Salerno province (Italy, was investigated. Particular attention was paid to the growth dynamics assessment and to the molecular identification of the indigenous lactic acid bacteria involved in the ripening of this cheese made with raw sheep milk without starter cultures. One batch was monitored taking 4 sample on 0, 30, 50 and 105 ripening days. Lactobacillus and Lactococcus were enumerated and randomly isolated on MRS and LM17 agar (32ºC x 48h -mesophilic flora- and 42°C x 48h -thermophilic flora, respectively. N. 66 presumptive lactic acid bacteria isolates, gram positive and catalase negative, were genotipically identified by Ribotyping. Mesophilic Lactobacillus remained at levels of 107 cfu/g during whole maturation time and thermophilic Lactobacillus, from initial values of 105 cfu/g, reached concentratios of 106 cfu/g at the end of maturation. Mesophilic and thermophilic Lactococcus showed, on average, levels of 106 since the beginning of the ripening. Ribotyping allowed to detect 4 lactic acid bacteria species: Enterococcus faecium (65,15%, Lactococcus lactis spp. cremoris (24,24%, Enterococcus faecalis (6,06% and Enterococcus durans (4,54%, showing the diversity of indigenous lactic acid bacteria of chilli “Tramonti” cheese.

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

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

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Seankham Soraya

2017-01-01

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

Dominant lactic acid bacteria and their technological properties isolated from the Himalayan ethnic fermented milk products.

Science.gov (United States)

Dewan, Sailendra; Tamang, Jyoti Prakash

2007-10-01

Ethnic people of the Himalayan regions of India, Nepal, Bhutan and China consume a variety of indigenous fermented milk products made from cows milk as well as yaks milk. These lesser-known ethnic fermented foods are dahi, mohi, chhurpi, somar, philu and shyow. The population of lactic acid bacteria (LAB) ranged from 10(7) to 10(8) cfu/g in these Himalayan milk products. A total of 128 isolates of LAB were isolated from 58 samples of ethnic fermented milk products collected from different places of India, Nepal and Bhutan. Based on phenotypic characterization including API sugar test, the dominant lactic acid bacteria were identified as Lactobacillus bifermentans, Lactobacillus paracasei subsp. pseudoplantarum, Lactobacillus kefir, Lactobacillus hilgardii, Lactobacillus alimentarius, Lactobacillus paracasei subsp. paracasei, Lactobacillus plantarum, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris and Enterococcus faecium. LAB produced a wide spectrum of enzymes and showed high galactosidase, leucine-arylamidase and phosphatase activities. They showed antagonistic properties against selected Gram-negative bacteria. None of the strains produced bacteriocin and biogenic amines under the test conditions used. Most strains of LAB coagulated skim milk with a moderate drop in pH. Some strains of LAB showed a high degree of hydrophobicity, suggesting these strains may have useful adhesive potential. This paper is the first report on functional lactic acid bacterial composition in some lesser-known ethnic fermented milk products of the Himalayas.

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

Science.gov (United States)

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

2017-11-01

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

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Lactic acid bacteria from chicken carcasses with inhibitory activity against Salmonella spp. and Listeria monocytogenes.

Science.gov (United States)

Sakaridis, I; Soultos, N; Dovas, C I; Papavergou, E; Ambrosiadis, I; Koidis, P

2012-02-01

This study was conducted to isolate psychrotrophic lactic acid bacteria (LAB) from chicken carcasses with inhibitory activity against strains of Salmonella spp. and Listeria monocytogenes. A total of 100 broiler samples were examined for the presence of LAB. Ninety-two LAB isolates that showed antimicrobial effects against Salmonella spp. and L. monocytogenes were further analysed to examine their LAB (Gram-positive, catalase negative, oxidase negative) and psychrotrophic characteristics (ability to grow at 7 °C). Fifty isolates were further selected and identified initially using standard biochemical tests in miniature (Micro-kits API CH 50) and then by sequencing of the 16s-23s rRNA gene boundary region (Intergenic Spacer Region). By molecular identification, these isolates were classified into 5 different LAB species: Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus johnsonii, Pediococcus acidilactici, and Lactobacillus paralimentarius. None of the isolates produced tyramine or histamine. Copyright © 2011 Elsevier Ltd. All rights reserved.

Materials and methods for efficient lactic acid production

Science.gov (United States)

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

2013-04-23

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

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.

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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

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Marcela Piassi Bernardo

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

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.

The Causes of Post-Operative Meningitis: The Comparison Of Gram-Negative and Gram-Positive Pathogens.

Science.gov (United States)

Kurtaran, Behice; Kuscu, Ferit; Ulu, Aslihan; Inal, Ayse Seza; Komur, Suheyla; Kibar, Filiz; Cetinalp, Nuri Eralp; Ozsoy, Kerem Mazhar; Arslan, Yusuf Kemal; Aksu, Hasan Salih; Tasova, Yesim

2017-06-20

In this study, we aim to determine the microbiological etiology in critically ill neurosurgical patients with nosocomial meningitis (NM) and show the impact of Gram-negative rods and differences of patient's characteristics, clinical and prognostic measures between Gram-negative and Gram-positive meningitis. In this prospective, one center study we reviewed all adult patients hospitalized during a 12-year period and identified pathogens isolated from post-neurosurgical cases of NM. Demographic, clinical, and treatment characteristics were noted from the medical records. Of the 134 bacterial NM patients, 78 were male and 56 were female, with a mean age of 46±15.9 and median age of 50 (18-80) years. 141 strains isolated; 82 (58.2%) were Gram negative, 59 (41.8%) were Gram positive. Most common isolated microorganism was Acinetobacter baumannii (%34.8). In comparison of mortality data shows that the patients who have meningitis with Gram-negative pathogens have higher mortality than with Gram positives (p=0.034). The duration between surgery and meningitis was shorter in Gram negative meningitis cases compared to others (p=0.045) but the duration between the diagnosis and death was shorter in Gram-positive meningitis cases compared to Gram negatives (p= 0.017). CSF protein and lactate level were higher and glucose level was lower in cases of NM with Gram negatives (p value were respectively, 0.022, 0.039 and 0.049). As conclusions; in NM, Gram-negative pathogens were seen more frequently; A.baumanni was the predominant pathogen; and NM caused by Gram negatives had worse clinical and laboratory characteristic and prognostic outcome than Gram positives.

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

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.

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:

Different Use of Cell Surface Glycosaminoglycans As Adherence Receptors to Corneal Cells by Gram Positive and Gram Negative Pathogens

Science.gov (United States)

García, Beatriz; Merayo-Lloves, Jesús; Rodríguez, David; Alcalde, Ignacio; García-Suárez, Olivia; Alfonso, José F.; Baamonde, Begoña; Fernández-Vega, Andrés; Vazquez, Fernando; Quirós, Luis M.

2016-01-01

The epithelium of the cornea is continuously exposed to pathogens, and adhesion to epithelial cells is regarded as an essential first step in bacterial pathogenesis. In this article, the involvement of glycosaminoglycans in the adhesion of various pathogenic bacteria to corneal epithelial cells is analyzed. All microorganisms use glycosaminoglycans as receptors, but arranged in different patterns depending on the Gram-type of the bacterium. The heparan sulfate chains of syndecans are the main receptors, though other molecular species also seem to be involved, particularly in Gram-negative bacteria. Adherence is inhibited differentially by peptides, including heparin binding sequences, indicating the participation of various groups of Gram-positive, and -negative adhesins. The length of the saccharides produces a major effect, and low molecular weight chains inhibit the binding of Gram-negative microorganisms but increase the adherence of Gram-positives. Pathogen adhesion appears to occur preferentially through sulfated domains, and is very dependent on N- and 6-O-sulfation of the glucosamine residue and, to a lesser extent, 2-O sulfation of uronic acid. These data show the differential use of corneal receptors, which could facilitate the development of new anti-infective strategies. PMID:27965938

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.

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

Science.gov (United States)

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

2016-01-01

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

Isolation of Lactic Acid Bacteria That Produce Protease and Bacteriocin-Like Substance From Mud Crab (Scylla sp. Digestive Tract (Isolasi Bakteri Asam Laktat yang Menghasilkan Protease dan Senyawa Bacteriocin-Like dari Saluran Pencernaan Kepiting

Directory of Open Access Journals (Sweden)

Heru Pramono

2015-03-01

Kata kunci: Bakteri Asam Laktat, Bakteriosin-like substance, Protease, Scylla  sp. Digestive tract is complex environment consist of large amount of bacteria’s species. Fish intestine bacteria consist of aerobic or facultative anaerob bacteria which can produce antibacterial and enzym. The objectives of this research were to isolated lactic acid bacteria that produce bacteriocin-like and protease from mud crab digestive tract. Isolation and characterization of isolates were conducted employing media MRS.  Neutralized cell free supernatant of isolates were tested using disc diffusion agar of against pathogenic and spoilage bacteria to indicate bacteriocin-like-producing lactic acid bacteria. Protease-producing isolate was tested using disc diffusion method in casein agar. Among a hundred isolates, 96 isolates were showed clear zone in MRS+CaCO3,, catalase negative, and Gram positive bacteria. Thirty four isolates produced protease and only four isolates (i.e. IKP29, IKP30, IKP52, and IKP94 showed strong inhibition against pathogenic and spoilage bacteria. There were three patterns of inhibition among three isolates against Bacillus subtilis, Staphylococcus aureus, Eschericia coli, and Salmonella sp. All three isolates showed potential uses for produce starter culture for fishery product fermentation purpose. This is the first report of isolation lactic acid bacteria that produced protease and bacteriocin-like from digestive tract of mud crab. Keywords: Lactic acid bacteria, Bacteriocin-like substance, Protease, Scylla  sp.

Isolation and identification of probiotic lactic acid bacteria from donkey,s milk

Directory of Open Access Journals (Sweden)

Mohamad javad Akrami

2016-02-01

Full Text Available Background : The utilization of donkey’s milk is increasing with regard to nutritional values and non-allergenic proteins. Donkey’s milk microbiota, especially lactic acid bacteria (LAB has not yet been fully identified. This study was conducted to identify and isolate LAB with probiotic properties. Materials and Methods: Specific culture-dependent techniques and standard microbiology methods were used to identify LAB. 250 isolates were randomly picked from different donkey’s milk samples different farms in Alashtar, north of Lorestan province, Iran. Gram-staining, catalase reaction, motility test, growth at different temperatures, pH 9.6 and in presence of 6.5% NaCl as well as the ability to ferment different sugars, sodium hippurate hydrolysis and light microscope analysis were investigated. Results: Out of 250 isolates, 20 isolates were gram-positive, catalase-negative and cocci form. Enterococcus and Streptoccus genera were dominant LAB in donkey’s milk. Entreococcus faecalis (55% and Streptococcus devriesei (45% were among the predominant species. The results of this experiment, for the first time, reported the occurrence of Streptococcus devriesei in donkey’s milk in Iran. Conclusion: Despite high lysozyme concentration, donkey’s milk rich in probiotic LAB can be used to feed infants with allergy to cow’s milk proteins. Both Entreococcus and Streptococcus bacteria produce different types of bacteriocins which are effective against a wide range of different type of infections. Occurrence of Streptococcus devriesei in donkey,s milk may provide new research field in Iran.

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

Science.gov (United States)

2010-07-01

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

Biopropionic acid production via molybdenumcatalyzed deoxygenation of lactic acid

NARCIS (Netherlands)

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

2013-01-01

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

Evaluation of different lactic acid bacterial strains for probiotic characteristics

OpenAIRE

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

2013-01-01

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

Mid-infrared spectroscopic assessment of nanotoxicity in gram-negative vs. gram-positive bacteria.

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Heys, Kelly A; Riding, Matthew J; Strong, Rebecca J; Shore, Richard F; Pereira, M Glória; Jones, Kevin C; Semple, Kirk T; Martin, Francis L

2014-03-07

Nanoparticles appear to induce toxic effects through a variety of mechanisms including generation of reactive oxygen species (ROS), physical contact with the cell membrane and indirect catalysis due to remnants from manufacture. The development and subsequent increasing usage of nanomaterials has highlighted a growing need to characterize and assess the toxicity of nanoparticles, particularly those that may have detrimental health effects such as carbon-based nanomaterials (CBNs). Due to interactions of nanoparticles with some reagents, many traditional toxicity tests are unsuitable for use with CBNs. Infrared (IR) spectroscopy is a non-destructive, high throughput technique, which is unhindered by such problems. We explored the application of IR spectroscopy to investigate the effects of CBNs on Gram-negative (Pseudomonas fluorescens) and Gram-positive (Mycobacterium vanbaalenii PYR-1) bacteria. Two types of IR spectroscopy were compared: attenuated total reflection Fourier-transform infrared (ATR-FTIR) and synchrotron radiation-based FTIR (SR-FTIR) spectroscopy. This showed that Gram-positive and Gram-negative bacteria exhibit differing alterations when exposed to CBNs. Gram-positive bacteria appear more resistant to these agents and this may be due to the protection afforded by their more sturdy cell wall. Markers of exposure also vary according to Gram status; Amide II was consistently altered in Gram-negative bacteria and carbohydrate altered in Gram-positive bacteria. ATR-FTIR and SR-FTIR spectroscopy could both be applied to extract biochemical alterations induced by each CBN that were consistent across the two bacterial species; these may represent potential biomarkers of nanoparticle-induced alterations. Vibrational spectroscopy approaches may provide a novel means of fingerprinting the effects of CBNs in target cells.

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.

Decomposition and detoxification of aflatoxin B1 by lactic acid.

Science.gov (United States)

Aiko, Visenuo; Edamana, Prasad; Mehta, Alka

2016-04-01

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

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

Science.gov (United States)

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

2018-03-01

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

Heme and menaquinone induced electron transport in lactic acid bacteria

NARCIS (Netherlands)

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

2009-01-01

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

Lactic Acid Bacteria : embarking on 30 more years of research

NARCIS (Netherlands)

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

2014-01-01

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

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

Science.gov (United States)

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

2010-05-01

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

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

Science.gov (United States)

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

2017-09-01

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

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

Science.gov (United States)

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

2018-04-05

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

Effects of lactic acid on astrocytes in primary culture.

Science.gov (United States)

Norenberg, M D; Mozes, L W; Gregorios, J B; Norenberg, L O

1987-03-01

Excessive tissue lactic acidosis is considered to be detrimental to the central nervous system (CNS) and may adversely affect recovery from anoxia, ischemia, trauma and epilepsy. Since astrocytes are believed to play a role in pH regulation in the CNS, we studied the effect of this acid on primary astrocyte cultures. Cells exposed to lactic acid showed chromatin clumping, an increase of lipid and dense bodies, a loss of polyribosomal clusters, slightly increased cytoplasmic lucency, swollen mitochondria and tangled intermediate filaments. These alterations progressed with lower pH and longer exposure. Irreversible changes occurred one to two hours after exposure at pH 6; after 30 to 60 minutes (min) at pH 5.5 and after ten to 30 min at pH 5. Comparable results were obtained with the use of other weak acids indicating that the observed changes were due to increased hydrogen ion concentration rather than secondary to lactate per se. Additionally, various concentrations of lactic acid adjusted to identical pH produced similar morphologic alterations. Thus, while lactic acid caused marked and at times irreversible alterations in astrocytes, severe and prolonged acidosis was required to produce such injurious effects. This relative resistance of astrocytes to acidosis is in keeping with their potential role in pH regulation in brain.

Evaluation of the Verigene Gram-positive blood culture nucleic acid test for rapid detection of bacteria and resistance determinants.

Science.gov (United States)

Wojewoda, Christina M; Sercia, Linda; Navas, Maria; Tuohy, Marion; Wilson, Deborah; Hall, Geraldine S; Procop, Gary W; Richter, Sandra S

2013-07-01

Rapid identification of pathogens from blood cultures can decrease lengths of stay and improve patient outcomes. We evaluated the accuracy of the Verigene Gram-positive blood culture (BC-GP) nucleic acid test for investigational use only (Nanosphere, Inc., Northbrook, IL) for the identification of Gram-positive bacteria from blood cultures. The detection of resistance genes (mecA in Staphylococcus aureus and Staphylococcus epidermidis and vanA or vanB in Enterococcus faecium and Enterococcus faecalis) by the BC-GP assay also was assessed. A total of 186 positive blood cultures (in BacT/Alert FA bottles) with Gram-positive cocci observed with Gram staining were analyzed using the BC-GP assay. The BC-GP results were compared with the identification and susceptibility profiles obtained with routine methods in the clinical laboratory. Discordant results were arbitrated with additional biochemical, cefoxitin disk, and repeat BC-GP testing. The initial BC-GP organism identification was concordant with routine method results for 94.6% of the blood cultures. Only 40% of the Streptococcus pneumoniae identifications were correct. The detection of the mecA gene for 69 blood cultures with only S. aureus or S. epidermidis was concordant with susceptibility testing results. For 3 of 6 cultures with multiple Staphylococcus spp., mecA detection was reported but was correlated with oxacillin resistance in a species other than S. aureus or S. epidermidis. The detection of vanA agreed with susceptibility testing results for 45 of 46 cultures with E. faecalis or E. faecium. Comparison of the mean times to results for each organism group showed that BC-GP results were available 31 to 42 h earlier than phenotypic identifications and 41 to 50 h earlier than susceptibility results.

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

Science.gov (United States)

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

2010-06-01

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

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

Science.gov (United States)

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

2018-03-01

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

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

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

Science.gov (United States)

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

2014-01-01

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

Catalytic Cracking of Lactide and Poly(Lactic Acid) to Acrylic Acid at Low Temperatures.

Science.gov (United States)

Terrade, Frédéric G; van Krieken, Jan; Verkuijl, Bastiaan J V; Bouwman, Elisabeth

2017-05-09

Despite being a simple dehydration reaction, the industrially relevant conversion of lactic acid to acrylic acid is particularly challenging. For the first time, the catalytic cracking of lactide and poly(lactic acid) to acrylic acid under mild conditions is reported with up to 58 % yield. This transformation is catalyzed by strong acids in the presence of bromide or chloride salts and proceeds through simple S N 2 and elimination reactions. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

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

OpenAIRE

Riley, T V

1985-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

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

Directory of Open Access Journals (Sweden)

Abdullah Abdullah

2012-01-01

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

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

Science.gov (United States)

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

2015-05-03

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

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

DEFF Research Database (Denmark)

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

2008-01-01

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

Gram positive and Gram negative bacteria differ in their sensitivity to cold plasma

Science.gov (United States)

Mai-Prochnow, Anne; Clauson, Maryse; Hong, Jungmi; Murphy, Anthony B.

2016-12-01

Cold atmospheric-pressure plasma (CAP) is a relatively new method being investigated for antimicrobial activity. However, the exact mode of action is still being explored. Here we report that CAP efficacy is directly correlated to bacterial cell wall thickness in several species. Biofilms of Gram positive Bacillus subtilis, possessing a 55.4 nm cell wall, showed the highest resistance to CAP, with less than one log10 reduction after 10 min treatment. In contrast, biofilms of Gram negative Pseudomonas aeruginosa, possessing only a 2.4 nm cell wall, were almost completely eradicated using the same treatment conditions. Planktonic cultures of Gram negative Pseudomonas libanensis also had a higher log10 reduction than Gram positive Staphylococcus epidermidis. Mixed species biofilms of P. aeruginosa and S. epidermidis showed a similar trend of Gram positive bacteria being more resistant to CAP treatment. However, when grown in co-culture, Gram negative P. aeruginosa was more resistant to CAP overall than as a mono-species biofilm. Emission spectra indicated OH and O, capable of structural cell wall bond breakage, were present in the plasma. This study indicates that cell wall thickness correlates with CAP inactivation times of bacteria, but cell membranes and biofilm matrix are also likely to play a role.

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

Science.gov (United States)

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

2017-06-01

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

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.

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....

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

OpenAIRE

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

2011-01-01

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

Effects of a series of acidic drugs on L-lactic acid transport by the monocarboxylate transporters MCT1 and MCT4.

Science.gov (United States)

Leung, Yat Hei; Belanger, Francois; Lu, Jennifer; Turgeon, Jacques; Michaud, Veronique

2018-03-07

Drug-induced myopathy is a serious side effect that often requires removal of a medication from a drug regimen. For most drugs, the underlying mechanism of drug-induced myopathy remains unclear. Monocarboxylate transporters (MCTs) mediate L-lactic acid transport, and inhibition of MCTs may potentially lead to perturbation of L-lactic acid accumulation and muscular disorders. Therefore, we hypothesized that L-lactic acid transport may be involved in the development of drug-induced myopathy. The aim of this study was to assess the inhibitory potential of 24 acidic drugs on L-lactic acid transport using breast cancer cell lines Hs578T and MDA-MB-231, which selectively express MCT1 and MCT4, respectively. The influx transport of L-lactic acid was minimally inhibited by all drugs tested. The efflux transport was next examined: loratadine (IC50: 10 and 61 µM) and atorvastatin (IC50: 78 and 41 µM) demonstrated the greatest potency for inhibition of L-lactic acid efflux by MCT1 and MCT4, respectively. Acidic drugs including fluvastatin, cerivastatin, simvastatin acid, lovastatin acid, irbesartan and losartan exhibited weak inhibitory potency on L-lactic acid efflux. Our results suggest that some acidic drugs, such as loratadine and atorvastatin, can inhibit the efflux transport of L-lactic acid. This inhibition may cause an accumulation of intracellular L-lactic acid leading to acidification and muscular disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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.

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

African Journals Online (AJOL)

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

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

Science.gov (United States)

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

2010-12-01

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

Lactic acid bacteria and the human gastrointestinal tract

DEFF Research Database (Denmark)

Hove, H; Nørgaard, H; Mortensen, P B

1999-01-01

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

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. Copyright © 2013. Published by Elsevier Ltd.

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

Energy Technology Data Exchange (ETDEWEB)

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

1996-05-10

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

Distribution of multi-resistant Gram-negative versus Gram-positive bacteria in the hospital inanimate environment.

Science.gov (United States)

Lemmen, S W; Häfner, H; Zolldann, D; Stanzel, S; Lütticken, R

2004-03-01

We prospectively studied the difference in detection rates of multi-resistant Gram-positive and multi-resistant Gram-negative bacteria in the inanimate environment of patients harbouring these organisms. Up to 20 different locations around 190 patients were surveyed. Fifty-four patients were infected or colonized with methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant enterococci (VRE) and 136 with multi-resistant Gram-negative bacteria. The environmental detection rate for MRSA or VRE was 24.7% (174/705 samples) compared with 4.9% (89/1827 samples) for multi-resistant Gram-negative bacteria (PGram-positive bacteria were isolated more frequently than Gram-negatives from the hands of patients (PGram-positive and Gram-negative isolates. Our results suggest that the inanimate environment serves as a secondary source for MRSA and VRE, but less so for Gram-negative bacteria. Thus, strict contact isolation in a single room with complete barrier precautions is recommended for MRSA or VRE; however, for multi-resistant Gram-negative bacteria, contact isolation with barrier precautions for close contact but without a single room seems sufficient. This benefits not only the patients, but also the hospital by removing some of the strain placed on already over-stretched resources.

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...

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

Science.gov (United States)

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

2011-05-01

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

Lactic acid delays the inflammatory response of human monocytes

Energy Technology Data Exchange (ETDEWEB)

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

2015-02-13

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

Lactic acid delays the inflammatory response of human monocytes

International Nuclear Information System (INIS)

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

2015-01-01

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

Potential of lactic acid bacteria as suppressors of wine allergies

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Yıldırım Hatice Kalkan

2017-01-01

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

Heme and menaquinone induced electron transport in lactic acid bacteria

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Santos Filipe

2009-05-01

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

Integrated production of lactic acid and biomass on distillery stillage.

Science.gov (United States)

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

2013-09-01

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

Heme and menaquinone induced electron transport in lactic acid bacteria.

Science.gov (United States)

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

2009-05-29

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

Isolating and evaluating lactic acid bacteria strains for effectiveness on silage quality at low temperatures on the Tibetan Plateau.

Science.gov (United States)

Wang, Siran; Yuan, Xianjun; Dong, Zhihao; Li, Junfeng; Shao, Tao

2017-11-01

Four lactic acid bacteria (LAB) strains isolated from straw silages on the Tibetan Plateau were characterized, and their effects on the fermentation quality of Italian ryegrass (Lolium multiflorum Lam.) at different temperatures (10°C, 15°C and 25°C) were studied. These LAB isolates were evaluated using the acids production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All the isolates (M1, LM8, LO7 and LOG9) could grow at 5-20°C, pH 3.5-7.0 and NaCl (3.0%, 6.5%). Strains M1, LM8, LO7 and LOG9 were identified as Lactobacillus plantarum, L. coryniformis, Pediococcus pentosaceus and P. acidilactici, respectively, by sequencing 16S ribosomal DNA. The four isolates were added to Italian ryegrass for ensiling for 30 days at various temperatures. Compared with the corresponding control, inoculating with isolates M1, LM8 and LO7 could improve the silage quality of Italian ryegrass at low temperatures, indicated by significantly (P lactic acid (LA) contents and ratios of lactic acid/acetic acid (LA/AA), and significantly (P < 0.05) lower pH and ammonia nitrogen/total nitrogen (AN/TN). Compared with other isolates, LM8 performed better at 10°C and 15°C, indicated by the higher (P < 0.05) LA content and ratio of LA/AA, and the lower (P < 0.05) pH and AN/TN. © 2017 Japanese Society of Animal Science.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-07-01

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

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

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

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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.

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

Science.gov (United States)

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

2016-11-01

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

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

Science.gov (United States)

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

An optimized staining technique for the detection of Gram positive and Gram negative bacteria within tissue.

Science.gov (United States)

Becerra, Sandra C; Roy, Daniel C; Sanchez, Carlos J; Christy, Robert J; Burmeister, David M

2016-04-12

Bacterial infections are a common clinical problem in both acute and chronic wounds. With growing concerns over antibiotic resistance, treatment of bacterial infections should only occur after positive diagnosis. Currently, diagnosis is delayed due to lengthy culturing methods which may also fail to identify the presence of bacteria. While newer costly bacterial identification methods are being explored, a simple and inexpensive diagnostic tool would aid in immediate and accurate treatments for bacterial infections. Histologically, hematoxylin and eosin (H&E) and Gram stains have been employed, but are far from optimal when analyzing tissue samples due to non-specific staining. The goal of the current study was to develop a modification of the Gram stain that enhances the contrast between bacteria and host tissue. A modified Gram stain was developed and tested as an alternative to Gram stain that improves the contrast between Gram positive bacteria, Gram negative bacteria and host tissue. Initially, clinically relevant strains of Pseudomonas aeruginosa and Staphylococcus aureus were visualized in vitro and in biopsies of infected, porcine burns using routine Gram stain, and immunohistochemistry techniques involving bacterial strain-specific fluorescent antibodies as validation tools. H&E and Gram stain of serial biopsy sections were then compared to a modification of the Gram stain incorporating a counterstain that highlights collagen found in tissue. The modified Gram stain clearly identified both Gram positive and Gram negative bacteria, and when compared to H&E or Gram stain alone provided excellent contrast between bacteria and non-viable burn eschar. Moreover, when applied to surgical biopsies from patients that underwent burn debridement this technique was able to clearly detect bacterial morphology within host tissue. We describe a modification of the Gram stain that provides improved contrast of Gram positive and Gram negative microorganisms within host

Antifungal Poly(lactic acid) Films Containing Thymol and Carvone

OpenAIRE

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

2016-01-01

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

Screening for Direct Production of Lactic Acid from Rice Starch Waste by Geobacillus stearothermophilus

Directory of Open Access Journals (Sweden)

Kunasundari Balakrishnan

2017-01-01

Full Text Available Lactic acid recently became an important chemical where it is widely used in many industries such as food, cosmetic, chemical and pharmaceutical industry. The present study focuses on the screening for lactic acid production from rice starch waste using a thermophilic amylolytic bacterium, Geobacillus stearothermophilus. There is no information available on direct fermentation of lactic acid from rice starch waste using G. stearothermophilus. The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentration of nitrogen and carbon sources on the lactic acid production were assessed. The highest concentration of lactic acid produced was 5.65 ± 0.07 g/L at operating conditions of 60°C, pH 5.5, 48 h, 200 rpm of agitation speed with 5% concentrations of both carbon and nitrogen source. The findings indicated that rice starch waste can be successfully converted to lactic acid by G. stearothermophilus.

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

Science.gov (United States)

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

2017-01-26

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

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

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F. G. Orozco

2014-01-01

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

Recovery of vancomycin-resistant gram-positive cocci from children.

OpenAIRE

Green, M; Wadowsky, R M; Barbadora, K

1990-01-01

A cross-sectional survey of vancomycin-resistant gram-positive cocci (VRGPC) in the feces of children was initiated after several bacteremic infections with these organisms occurred at our hospital. A selective medium consisting of colistin-nalidixic acid agar, 5% sheep blood, vancomycin (5 mg/liter), and amphotericin B (8 mg/liter) was developed to isolate VRGPC. A single stool specimen submitted to the clinical microbiology laboratory from each of 48 patients was inoculated onto the medium....

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

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

Science.gov (United States)

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

2018-02-09

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

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

Science.gov (United States)

2013-01-01

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

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

International Nuclear Information System (INIS)

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

2006-09-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1986-06-01

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

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

International Nuclear Information System (INIS)

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

2007-01-01

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

Methods for targetted mutagenesis in gram-positive bacteria

Science.gov (United States)

Yang, Yunfeng

2014-05-27

The present invention provides a method of targeted mutagenesis in Gram-positive bacteria. In particular, the present invention provides a method that effectively integrates a suicide integrative vector into a target gene in the chromosome of a Gram-positive bacterium, resulting in inactivation of the target gene.

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

International Nuclear Information System (INIS)

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

2008-01-01

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

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...

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

Science.gov (United States)

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

1973-01-01

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

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.

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

Directory of Open Access Journals (Sweden)

Nevijo Zdolec

2007-04-01

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

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

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.

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

African Journals Online (AJOL)

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

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

Science.gov (United States)

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

2018-01-31

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

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

African Journals Online (AJOL)

Reviwer

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

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

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

OpenAIRE

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

2016-01-01

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

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.

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. Copyright © 2012 Elsevier Ltd. All rights reserved.

THE SEARCH AND PROPERTIES OF LACTIC ACID BACTERIA PERSPECTIVE FOR BIOTECHNOLOGY

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Naumenko О. V.

2014-10-01

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

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

Science.gov (United States)

Lonvaud-Funel, A

1999-01-01

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

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

Science.gov (United States)

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

2018-03-01

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

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.

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

Science.gov (United States)

Kaur, Baljinder; 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. PMID:24066293

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

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

Science.gov (United States)

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

2010-08-01

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

Glass bead transformation method for gram-positive bacteria

OpenAIRE

Rattanachaikunsopon, Pongsak; Phumkhachorn, Parichat

2009-01-01

A simple, inexpensive and reproducible transformation method was developed for Gram-positive bacteria. It was based on agitation of bacterial protoplasts with glass beads in the presence of DNA and polyethylene glycol. By using this method, introduction of pGK12 into protoplasts of several strains of Gram-positive bacteria was achieved.

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-04-20

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

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

African Journals Online (AJOL)

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

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

Science.gov (United States)

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

2015-01-01

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

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

Isolation of lactic acid bacteria from kantong, a condiment produced from the fermentation of kapok (Ceiba pentandra) seeds and cassava (Manihot esculentum) flour

DEFF Research Database (Denmark)

Kpikpi, Elmer Nayra; Glover, Richard L.K.; Dzogbefia, Victoria Pearl

2010-01-01

in the initial pH from 6.9 before fermentation to 4.9 after fermentation with change in color of the product from grayish to dark brown as well as the development of a more desirable flavor. Lactic acid bacteria (LAB) with counts between 106 and 109 cfu/g were isolated on MRS agar and subjected to Gram, catalase...

Comparative activity of ceftobiprole against Gram-positive and Gram-negative isolates from Europe and the Middle East: the CLASS study.

Science.gov (United States)

Rossolini, Gian M; Dryden, Matthew S; Kozlov, Roman S; Quintana, Alvaro; Flamm, Robert K; Läuffer, Jörg M; Lee, Emma; Morrissey, Ian; CLASS Study Group

2011-01-01

to assess the in vitro activity of ceftobiprole and comparators against a recent collection of Gram-positive and Gram-negative pathogens, in order to detect potential changes in susceptibility patterns, and to evaluate the Etest assay for ceftobiprole susceptibility testing. contemporary Gram-positive and Gram-negative isolates (excluding extended-spectrum β-lactamase-producing isolates) from across Europe and the Middle East were collected, and their susceptibility to ceftobiprole, vancomycin, teicoplanin, linezolid, ceftazidime and cefepime was assessed using the Etest method. Quality testing [using Etest and broth microdilution (BMD)] was conducted at a central reference laboratory. some 5041 Gram-positive and 4026 Gram-negative isolates were included. Against Gram-positive isolates overall, ceftobiprole had the lowest MIC50 (0.5 mg/L), compared with 1 mg/L for its comparators (vancomycin, teicoplanin and linezolid). Against methicillin-resistant Staphylococcus aureus, all four agents had a similar MIC90 (2 mg/L), but ceftobiprole had a 4-fold better MIC90 (0.5 mg/L) against methicillin-susceptible strains. Only 38 Gram-positive isolates were confirmed as ceftobiprole resistant. Among Gram-negative strains, 86.9%, 91.7% and 95.2% were susceptible to ceftobiprole, ceftazidime and cefepime, respectively. Pseudomonas aeruginosa was less susceptible to all three antimicrobials than any other Gram-negative pathogen. There was generally good agreement between local Etest results and those obtained at the reference laboratory (for ceftobiprole: 86.8% with Gram-negatives; and 94.7% with Gram-positives), as well as between results obtained by BMD and Etest methods (for ceftobiprole: 98.2% with Gram-negatives; and 98.4% with Gram-positives). ceftobiprole exhibits in vitro activity against a wide range of Gram-positive and Gram-negative pathogens, including multidrug-resistant strains. No changes in its known susceptibility profile were identified.

Separation and determination of the enantiomers of lactic acid and 2-hydroxyglutaric acid by chiral derivatization combined with GC-MS.

Science.gov (United States)

Ding, Xuemei; Lin, Shuhai; Weng, Hongbo; Liang, Jianying

2018-03-30

Lactic acid and 2-hydroxyglutaric acid are chiral metabolites that have two distinct d and l enantiomers with distinct biochemical properties. Perturbations of single enantiomeric form have been found to be closely related to certain diseases. The ability to differentiate the d and l enantiomers is therefore important for these disease studies. Herein, we describe a method for the separation and determination of lactic acid and 2-hydroxyglutaric acid enantiomers by chiral derivatization (with l-menthol and acetyl chloride) combined with gas chromatography and mass spectrometry. The two pairs of enantiomers mentioned above exhibited linear calibration curves with correlation coefficient (R 2 ) exceeding 0.99. The measured data were accurate in the acceptable recovery range of 88.17-102.30% with inter-day and intra-day precisions (relative standard deviations) in the 4.23-17.26% range. The limits of detection for d- lactic acid, l-lactic acid, d-2-hydroxyglutaric acid and l-2-hydroxyglutaric acid were 0.13, 0.11, 1.12 and 1.16 μM, respectively. This method was successfully applied to analyze mouse plasma. The d-lactic acid levels in type 2 diabetes mellitus mouse plasma were observed to be significantly higher (P lactic acid may serve as an indicator for type 2 diabetes mellitus. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Automated no-carrier-added synthesis of [1-11C]-labeled D- and L-enantiomers of lactic acid

International Nuclear Information System (INIS)

Drandarov, Konstantin; Schubiger, P. August; Westera, Gerrit

2006-01-01

The first purely chemical method for automated no-carrier-added synthesis of [1- 11 C]-labeled D(R)- and L(S)-2-hydroxypropanoic acid (lactic acid) was developed for experimental neurophysiology studies and position emission tomography (PET) diagnosis. Starting from sodium 1-hydroxyethanesulfonate and [ 11 C]HCN (trapped as [ 11 C]KCN) the intermediate DL-(R,S)-[1- 11 C]-2-hydroxypropanenitrile was prepared. Its rapid acid hydrolysis gave DL-(R,S)-[1- 11 C]lactic acid, which was isolated by preparative reversed phase HPLC and automatically injected on a second preparative C 18 HPLC column coated with a chiral selector, where both [1- 11 C]lactic acid enantiomers were separated by chiral ligand-exchange chromatography. Two novel chiral selectors for HPLC enantiomeric separation of α-hydroxy acids, namely D(R)- or L(S)-2-amino-3-methyl-3-(5-phenylpentylsulfanyl)-butanoic acid were utilized for the preparative HPLC separation of the [1- 11 C]lactic acid enantiomers. The preparation of the selectors and the coating procedure for the manufacturing of the preparative chiral HPLC columns are described. A highly efficient trap for [ 11 C]HCN is presented. The whole radiosynthesis is automated, takes about 45 min and leads to more than 80% decay corrected overall radiochemical yield of each enantiomer (up to 2.5 GBq) with over 99% radiochemical, chemical and enantiomeric purity. The specific activity at the end of the synthesis is about 400 GBq/μmol

Prognostic factors and monomicrobial necrotizing fasciitis: gram-positive versus gram-negative pathogens

Directory of Open Access Journals (Sweden)

Hsu Wei-Hsiu

2011-01-01

Full Text Available Abstract Background Monomicrobial necrotizing fasciitis is rapidly progressive and life-threatening. This study was undertaken to ascertain whether the clinical presentation and outcome for patients with this disease differ for those infected with a gram-positive as compared to gram-negative pathogen. Methods Forty-six patients with monomicrobial necrotizing fasciitis were examined retrospectively from November 2002 to January 2008. All patients received adequate broad-spectrum antibiotic therapy, aggressive resuscitation, prompt radical debridement and adjuvant hyperbaric oxygen therapy. Eleven patients were infected with a gram-positive pathogen (Group 1 and 35 patients with a gram-negative pathogen (Group 2. Results Group 2 was characterized by a higher incidence of hemorrhagic bullae and septic shock, higher APACHE II scores at 24 h post-admission, a higher rate of thrombocytopenia, and a higher prevalence of chronic liver dysfunction. Gouty arthritis was more prevalent in Group 1. For non-survivors, the incidences of chronic liver dysfunction, chronic renal failure and thrombocytopenia were higher in comparison with those for survivors. Lower level of serum albumin was also demonstrated in the non-survivors as compared to those in survivors. Conclusions Pre-existing chronic liver dysfunction, chronic renal failure, thrombocytopenia and hypoalbuminemia, and post-operative dependence on mechanical ventilation represent poor prognostic factors in monomicrobial necrotizing fasciitis. Patients with gram-negative monobacterial necrotizing fasciitis present with more fulminant sepsis.

Protamine-induced permeabilization of cell envelopes of gram-positive and gram-negative bacteria

DEFF Research Database (Denmark)

Johansen, Charlotte; Verheul, A.; Gram, Lone

1997-01-01

carboxyfluorescein and ATP after 2 to 5 min. Maximum antibacterial activity was reached at alkaline pH and in the absence of divalent cations. The efficient permeabilization of cell envelopes of both gram-positive and gram-negative bacteria suggests that protamine causes a general disruption of the cell envelope...

Antifungal Poly(lactic acid Films Containing Thymol and Carvone

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Boonruang Kanchana

2016-01-01

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

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

NARCIS (Netherlands)

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

2015-01-01

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

Accelerated fatigue of dentin with exposure to lactic acid.

Science.gov (United States)

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

2013-11-01

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

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

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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.

Probing interaction of Gram-positive and Gram-negative bacterial cells with ZnO nanorods

Energy Technology Data Exchange (ETDEWEB)

Jain, Aanchal; Bhargava, Richa; Poddar, Pankaj, E-mail: p.poddar@ncl.res.in

2013-04-01

In the present work, the physiological effects of the ZnO nanorods on the Gram positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Escherichia coli and Aerobacter aerogenes) bacterial cells have been studied. The analysis of bacterial growth curves for various concentrations of ZnO nanorods indicates that Gram positive and Gram negative bacterial cells show inhibition at concentrations of ∼ 64 and ∼ 256 μg/mL respectively. The marked difference in susceptibility towards nanorods was also validated by spread plate and disk diffusion methods. In addition, the scanning electron micrographs show a clear damage to the cells via changed morphology of the cells from rod to coccoid etc. The confocal optical microscopy images of these cells also demonstrate the reduction in live cell count in the presence of ZnO nanorods. These, results clearly indicate that the antibacterial activity of ZnO nanorods is higher towards Gram positive bacterium than Gram negative bacterium which indicates that the structure of the cell wall might play a major role in the interaction with nanostructured materials and shows high sensitivity to the particle concentration. Highlights: ► Effect of ZnO nanorods on the growth cycles of four bacterial strains. ► A relation has been established between growth rate of bacteria and concentration. ► Serious damage in the morphology of bacterial cells in the presence of ZnO nanorods. ► Microscopic studies to see the time dependent effect on bacterial cells.

Defining a role for Hfq in Gram-positive bacteria

DEFF Research Database (Denmark)

Nielsen, Jesper Sejrup; Lei, Lisbeth Kristensen; Ebersbach, Tine

2010-01-01

Small trans-encoded RNAs (sRNAs) modulate the translation and decay of mRNAs in bacteria. In Gram-negative species, antisense regulation by trans-encoded sRNAs relies on the Sm-like protein Hfq. In contrast to this, Hfq is dispensable for sRNA-mediated riboregulation in the Gram-positive species......-dependent and -independent mechanisms, thus adding another layer of complexity to sRNA-mediated riboregulation in Gram-positive species....

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.

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

African Journals Online (AJOL)

user

2011-02-07

Feb 7, 2011 ... the diversity and dynamics of lactic acid bacteria (LAB) population in fresh ..... combining morphological, biochemical and molecular data are important for ..... acid bacteria from fermented maize (Kenkey) and their interactions.

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

Science.gov (United States)

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

2010-10-01

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

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

Science.gov (United States)

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

2011-03-01

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

Study of Lactic Acid Thermal Behavior Using Thermoanalytical Techniques

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Andrea Komesu

2017-01-01

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

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

Science.gov (United States)

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

2015-01-01

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

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

Science.gov (United States)

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

2017-08-01

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

Gram-positive bacteria persisting in the food production environment

DEFF Research Database (Denmark)

Knøchel, Susanne; Harmsen, Morten; Knudsen, Bettina

2008-01-01

Many gram-positive bacteria are able to form aggregates or biofilms and resist external stress factors and some gram-positive pathogenic bacteria such as Listeria monocytogenes and Bacillus cereus may persist in the food production environment for extended periods. Most research has focussed...

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.

Antioxidant activity of probiotic lactic acid bacteria isolated from Mongolian airag

OpenAIRE

E Uugantsetseg; B Batjargal

2014-01-01

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

Antimicrobial Activity of Carbon Nanoparticles Isolated from Natural Sources against Pathogenic Gram-Negative and Gram-Positive Bacteria

International Nuclear Information System (INIS)

Varghese, S.; Jose, S.; Varghese, S.; Kuriakose, S.; Jose, S.

2013-01-01

This paper describes the isolation of carbon nanoparticles (CNPs) from kitchen soot, characterization of the CNPs by UV/visible spectroscopy, SEM and XRD, and their antimicrobial action. The antibacterial activity of the isolated carbon nanoparticles was tested against various pathogenic bacterial strains such as Gram-negative Proteus refrigere and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus and Streptococcus haemolyticus. The inhibition zones were measured, and it was found that the carbon nanoparticles isolated from natural sources are active against these Gram-negative and Gram-positive bacterial strains

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

Science.gov (United States)

Wijayasinghe, Rangani; Vasiljevic, Todor; Chandrapala, Jayani

2015-12-01

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

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

Science.gov (United States)

Darwin; WipaCharles; Cord-Ruwisch, Ralf

2018-01-01

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

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

Science.gov (United States)

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

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

Optimization of lactic acid production with immobilized Rhizopus ...

African Journals Online (AJOL)

sule

2012-04-26

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

Antibacterial properties of biosurfactants against selected Gram-positive and -negative bacteria.

Science.gov (United States)

Díaz De Rienzo, Mayri A; Stevenson, Paul; Marchant, Roger; Banat, Ibrahim M

2016-01-01

The antibacterial properties and ability to disrupt biofilms of biosurfactants (rhamnolipids, sophorolipids) and sodium dodecyl sulphate (SDS) in the presence and absence of selected organic acids were investigated. Pseudomonas aeruginosa PAO1 was inhibited by sophorolipids and SDS at concentrations >5% v/v, and the growth of Escherichia coli NCTC 10418 was also inhibited by sophorolipids and SDS at concentrations >5% and 0.1% v/v, respectively. Bacillus subtilis NCTC 10400 was inhibited by rhamnolipids, sophorolipids and SDS at concentrations >0.5% v/v of all three; the same effect was observed with Staphylococcus aureus ATCC 9144. The ability to attach to surfaces and biofilm formation of P. aeruginosa PAO1, E. coli NCTC 10418 and B. subtilis NCTC 10400 was inhibited by sophorolipids (1% v/v) in the presence of caprylic acid (0.8% v/v). In the case of S. aureus ATCC 9144, the best results were obtained using caprylic acid on its own. It was concluded that sophorolipids are promising compounds for the inhibition/disruption of biofilms formed by Gram-positive and Gram-negative microorganisms and this activity can be enhanced by the presence of booster compounds such as caprylic acid. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

In vitro Degradation of Butanediamine-Grafted Poly(DL-Lactic acids)

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The degradation of butanediamine-grafted poly(DL-lactic acid) polymers (BDPLAs) in vitro together with PDLLA and maleic anhydride-grafted poly(DL-lactic acid) polymers (MPLAs) was investigated by observation of the changes of the pH value of incubation media, and weight loss ratio during degradation duration of 12 weeks. The results reveal that the acidity of PDLLA degradation products was weakened or neutralized by grafting butanediamine onto PDLLA. A uniform degradation of BDPLAs was observed in comparison with an acidity-induced auto-accelerating degradation featured by PDLLA and MPLAs. The biodegradation behaviors of BDPLAs can be adjusted by controlling the content of BDA. BDPLAs might be a new derivative of PDLLA-based biodegradable materials for medical applications without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as that of PDLLA.

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

Science.gov (United States)

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

2018-03-27

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

Amino acid catabolism and generation of volatiles by lactic acid bacteria

OpenAIRE

Tavaria, F. K.; Dahl, S.; Carballo, F. J.; Malcata, F. X.

2002-01-01

Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180- d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino acids, when incubated independently with each amino acid in free form or with a mixture thereof. Attempts...

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.

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.

Conversion of acid hydrolysate of oil palm empty fruit bunch to L-lactic acid by newly isolated Bacillus coagulans JI12.

Science.gov (United States)

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

2013-06-01

Cost-effective conversion of lignocellulose hydrolysate to optically pure lactic acid is commercially attractive but very challenging. Bacillus coagulans JI12 was isolated from natural environment and used to produce L-lactic acid (optical purity > 99.5 %) from lignocellulose sugars and acid hydrolysate of oil palm empty fruit bunch (EFB) at 50 °C and pH 6.0 without sterilization of the medium. In fed-batch fermentation with 85 g/L initial xylose and 55 g/L xylose added after 7.5 h, 137.5 g/L lactic acid was produced with a yield of 98 % and a productivity of 4.4 g/L h. In batch fermentation of a sugar mixture containing 8.5 % xylose, 1 % glucose, and 1 % L-arabinose, the lactic acid yield and productivity reached 98 % and 4.8 g/L h, respectively. When EFB hydrolysate was used, 59.2 g/L of lactic acid was produced within 9.5 h at a yield of 97 % and a productivity of 6.2 g/L h, which are the highest among those ever reported from lignocellulose hydrolysates. These results indicate that B. coagulans JI12 is a promising strain for industrial production of L-lactic acid from lignocellulose hydrolysate.

Characterization And Identification Of Lactic Acid Bacteria From ...

African Journals Online (AJOL)

$hr3k

2013-06-05

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

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

Science.gov (United States)

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

2012-01-01

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

Interactions of the cell-wall glycopolymers of lactic acid bacteria with their bacteriophages

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Marie-Pierre eChapot-Chartier

2014-05-01

Full Text Available Lactic acid bacteria (LAB are Gram positive bacteria widely used in the production of fermented food in particular cheese and yoghurts. Bacteriophage infections during fermentation processes have been for many years a major industrial concern and have stimulated numerous research efforts. Better understanding of the molecular mechanisms of bacteriophage interactions with their host bacteria is required for the development of efficient strategies to fight against infections. The bacterial cell wall plays key roles in these interactions. First, bacteriophages must adsorb at the bacterial surface through specific interactions with receptors that are cell wall components. At next step, phages must overcome the barrier constituted by cell wall peptidoglycan to inject DNA inside bacterial cell. Also at the end of the infection cycle, phages synthesize endolysins able to hydrolyze peptidoglycan and lyse bacterial cells to release phage progeny. In the last decade, concomitant development of genomics and structural analysis of cell wall components allowed considerable advances in the knowledge of their structure and function in several model LAB. Here, we describe the present knowledge on the structure of the cell wall glycopolymers of the best characterized LAB emphasizing their structural variations and we present the available data regarding their role in bacteria-phage specific interactions at the different steps of the infection cycle.

Identification of exopolysaccharides-producing lactic acid bacteria ...

African Journals Online (AJOL)

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

The proteolytic systems of lactic acid bacteria

NARCIS (Netherlands)

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

1996-01-01

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

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

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Takuya Yamane

2018-03-01

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

Taurocholate Deconjugation and Cholesterol Binding by Indigenous Dadih Lactic Acid Bacteria

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USMAN PATO

2005-09-01

Full Text Available High serum cholesterol levels have been associated with an increased risk for human coronary heart disease. Lowering of serum cholesterol has been suggested to prevent the heart disease. To reduce serum cholesterol levels one may consumed diet supplementat of fermented dairy product such as dadih. Lactic acid bacteria present in dadih may alter serum cholesterol by directly bind to dietary cholesterol and/or deconjugation of bile salts. Acid and bile tolerance, deconjugation of sodium taurocholate, and the cholesterol-binding ability of lactic acid bacteria from dadih were examined. Among ten dadih lactic acid bacteria tested, six strains namely I-11, I-2775, K-5, I-6257, IS-7257, and B-4 could bind cholesterol and deconjugate sodium taurocholate. However, the last four strains were very sensitive to bile. Therefore, Lactobacillus fermentum I-11 and Leuconostoc lactis subsp. lactis I-2775 those were tolerant to acid and oxgall (bile and deconjugated sodium taurocholate and bound cholesterol could be recommended as probiotic to prevent coronary heart disease.

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

Science.gov (United States)

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

2013-03-01

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

Mass transfer behavior in lactic acid fermentation using immobilized lactobacillus delbrueckii

Energy Technology Data Exchange (ETDEWEB)

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

1995-08-20

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

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

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Blaženka Kos

2010-01-01

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

Lactic acid demineralization of shrimp shell and chitosan synthesis

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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.

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

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Taleghani Hamidreza Ghafouri

2016-03-01

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

ASIC3: A Lactic Acid Sensor for Cardiac Pain

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D.C. Immke

2001-01-01

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

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

International Nuclear Information System (INIS)

Bok, H.E.

1985-01-01

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

Gram-positive rods prevailing in teeth with apical periodontitis undergoing root canal treatment.

Science.gov (United States)

Chávez de Paz, L E; Molander, A; Dahlén, G

2004-09-01

To identify Gram-positive rods from root canals of teeth with apical periodontitis and to examine their associations with other species. Consecutive root canal samples (RCSs) from 139 teeth undergoing root canal treatment were analyzed prospectively for cultivable microbes. Gram-positive rods in the first RCS submitted after chemo-mechanical preparation were categorised to genus level by selective media and gas-liquid chromatography (GLC), and identified to species level by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Associations between organisms were measured by odds ratios (OR). In the first samples submitted a total of 158 Gram-positive rods, 115 Gram-positive cocci, 26 Gram-negative rods and 9 Gram-negative cocci, were identified. At genus levels Gram-positive rods were classified into: Lactobacillus spp. (38%), Olsenella spp. (18%), Propionibacterium spp. (13%), Actinomyces spp. (12%), Bifidobacterium spp. (13%) and Eubacterium spp. (6%). The most frequent species were Olsenella uli, Lactobacillus paracasei and Propionibacterium propionicum. In subsequent samples taken during treatment, Gram-positive rods were also identified, although the number of strains was considerably reduced. Positive associations were observed between members of the genus lactobacilli and Gram-positive cocci (OR>2). Olsenella uli and Lactobacillus spp. predominated over other Gram-positive rods. A possible association exists between Lactobacillus spp. and Gram-positive cocci in root canals of teeth with apical periodontitis receiving treatment.

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

OpenAIRE

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

2016-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

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

African Journals Online (AJOL)

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

Lactic acid peeling in superficial acne scarring in Indian skin.

Science.gov (United States)

Sachdeva, Silonie

2010-09-01

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

Amino acids in cell wall of Gram-positive bacterium Micrococcus sp. hsn08 with flocculation activity on Chlorella vulgaris biomass.

Science.gov (United States)

Li, Yi; Xu, Yanting; Zheng, Tianling; Wang, Hailei

2018-02-01

The aim of this work was to investigate the flocculation mechanism by Gram-positive bacterium, Micrococcus sp. hsn08 as a means for harvesting Chlorella vulgaris biomass. Bacterial cells of Micrococcus sp. hsn08 were added into algal culture to harvest algal cells through direct contacting with algae to form flocs. Viability dependence test confirmed that flocculation activity does not depend on live bacteria, but on part of the peptidoglycan. The further investigation has determined that amino acids in cell wall play an important role to flocculate algal cells. Positively charged calcium can combine bacterial and algal cells together, and form a bridge between them, thereby forming the flocs, suggesting that ions bridging is the main flocculation mechanism. These results suggest that bacterial cells of Micrococcus sp. hsn08 can be applied to harvest microalgae biomass with the help of amino acids in cell wall. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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.

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...

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

International Nuclear Information System (INIS)

Bjurling, P.; Laangstroem, B.

1990-01-01

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

Automated no-carrier-added synthesis of [1-{sup 11}C]-labeled D- and L-enantiomers of lactic acid

Energy Technology Data Exchange (ETDEWEB)

Drandarov, Konstantin [Center for Radiopharmaceutical Sciences, Swiss Federal Institute of Technology Zurich, University Hospital Zuerich, CH-8091 Zurich (Switzerland); Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Schubiger, P. August [Center for Radiopharmaceutical Sciences, Swiss Federal Institute of Technology Zurich, University Hospital Zuerich, CH-8091 Zurich (Switzerland); Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Westera, Gerrit [Center for Radiopharmaceutical Sciences, Swiss Federal Institute of Technology Zurich, University Hospital Zuerich, CH-8091 Zurich (Switzerland) and Paul Scherrer Institute, CH-5232 Villigen (Switzerland)]. E-mail: gerrit.westera@usz.ch

2006-12-15

The first purely chemical method for automated no-carrier-added synthesis of [1-{sup 11}C]-labeled D(R)- and L(S)-2-hydroxypropanoic acid (lactic acid) was developed for experimental neurophysiology studies and position emission tomography (PET) diagnosis. Starting from sodium 1-hydroxyethanesulfonate and [{sup 11}C]HCN (trapped as [{sup 11}C]KCN) the intermediate DL-(R,S)-[1-{sup 11}C]-2-hydroxypropanenitrile was prepared. Its rapid acid hydrolysis gave DL-(R,S)-[1-{sup 11}C]lactic acid, which was isolated by preparative reversed phase HPLC and automatically injected on a second preparative C{sub 18} HPLC column coated with a chiral selector, where both [1-{sup 11}C]lactic acid enantiomers were separated by chiral ligand-exchange chromatography. Two novel chiral selectors for HPLC enantiomeric separation of {alpha}-hydroxy acids, namely D(R)- or L(S)-2-amino-3-methyl-3-(5-phenylpentylsulfanyl)-butanoic acid were utilized for the preparative HPLC separation of the [1-{sup 11}C]lactic acid enantiomers. The preparation of the selectors and the coating procedure for the manufacturing of the preparative chiral HPLC columns are described. A highly efficient trap for [{sup 11}C]HCN is presented. The whole radiosynthesis is automated, takes about 45 min and leads to more than 80% decay corrected overall radiochemical yield of each enantiomer (up to 2.5 GBq) with over 99% radiochemical, chemical and enantiomeric purity. The specific activity at the end of the synthesis is about 400 GBq/{mu}mol.

Production of lactic acid from corn cobs through fermentation lactobacillus delbruekii

International Nuclear Information System (INIS)

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

2007-01-01

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

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)

Lactic Acid Bacterial Vaginosis among Outpatients in Addis Ababa ...

African Journals Online (AJOL)

Background: Bacterial vaginosis (BV) is a polymicrobial syndrome in which a decrease in vaginal acidity and concentration of lactobacilli is accompanied by an increase of other pathogenic micro-organisms. The distribution of lactic acid bacteria in vaginal environment of Ethiopian women has not been documented.

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.

Selective bowel decontamination results in gram-positive translocation.

Science.gov (United States)

Jackson, R J; Smith, S D; Rowe, M I

1990-05-01

Colonization by enteric gram-negative bacteria with subsequent translocation is believed to be a major mechanism for infection in the critically ill patient. Selective bowel decontamination (SBD) has been used to control gram-negative infections by eliminating these potentially pathogenic bacteria while preserving anaerobic and other less pathogenic organisms. Infection with gram-positive organisms and anaerobes in two multivisceral transplant patients during SBD led us to investigate the effect of SBD on gut colonization and translocation. Twenty-four rats received enteral polymixin E, tobramycin, amphotericin B, and parenteral cefotaxime for 7 days (PTA + CEF); 23 received parenteral cefotaxime alone (CEF), 19 received the enteral antibiotics alone (PTA), 21 controls received no antibiotics. Cecal homogenates, mesenteric lymph node (MLN), liver, and spleen were cultured. Only 8% of the PTA + CEF group had gram-negative bacteria in cecal culture vs 52% CEF, 84% PTA, and 100% in controls. Log Enterococcal colony counts were higher in the PTA + CEF group (8.0 + 0.9) vs controls (5.4 + 0.4) P less than 0.01. Translocation of Enterococcus to the MLN was significantly increased in the PTA + CEF group (67%) vs controls (0%) P less than 0.01. SBD effectively eliminates gram-negative organisms from the gut in the rat model. Overgrowth and translocation of Enterococcus suggests that infection with gram-positive organisms may be a limitation of SBD.

Phenotypic and genotypic characterization of lactic acid bacteria ...

African Journals Online (AJOL)

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

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

International Nuclear Information System (INIS)

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

1986-01-01

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

Lactic acid bacteria as a cell factory for riboflavin production.

Science.gov (United States)

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

2016-07-01

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

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

Science.gov (United States)

Kang, Shuhui

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

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.

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Dustborne and airborne gram-positive and gram-negative bacteria in high versus low ERMI homes

Science.gov (United States)

The study aimed at investigating Gram-positive and Gram-negative bacteria in moldy and non-moldy homes, as defined by the home's Environmental Relative Moldiness Index (ERMI) value. The ERMI values were determined from floor dust samples in 2010 and 2011 and homes were classified...

Methods for Confirming the Gram Reaction of Gram-variable Bacillus Species Isolated from Tobacco

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Morin A

2014-12-01

Full Text Available Bacillus is a predominant genus of bacteria isolated from tobacco. The Gram stain is the most commonly used and most important of all diagnostic staining techniques in microbiology. In order to help confirm the Gram positivity of Bacillus isolates from tobacco, three methods using the chemical differences of the cell wall and membrane of Gram-positive and Gram-negative bacteria were investigated: the KOH (potassium hydroxide, the LANA (L-alanine-4-nitroanilide, and the vancomycin susceptibility tests. When colonies of Gram-negative bacteria are treated with 3% KOH solution, a slimy suspension is produced, probably due to destruction of the cell wall and liberation of deoxyribonucleic acid (DNA. Gram-positive cell walls resist KOH treatment. The LANA test reveals the presence of a cell wall aminopeptidase that hydrolyzes the L-alanine-4-nitroanilide in Gram-negative bacteria. This enzyme is absent in Gram-positive bacteria. Vancomycin is a glycopeptide antibiotic inhibiting the cell wall peptido-glycan synthesis of Gram-positive microorganisms. Absence of lysis with KOH, absence of hydrolysis of LANA, and susceptibility to vancomycin were used with the Gram reaction to confirm the Gram positivity of various Bacillus species isolated from tobacco. B. laevolacticus excepted, all Bacillus species tested showed negative reactions to KOH and LANA tests, and all species were susceptible to vancomycin (5 and 30 µg.

Isolation and Identification of Lactic Acid Bacteria Isolated from a Traditional Jeotgal Product in Korea

Science.gov (United States)

Cho, Gyu Sung; Do, Hyung Ki

2006-06-01

Seventeen lactic acid bacterial strains (LAB) were isolated using MRS agar medium from Jeotgal, a Korean fermented food, purchased at the Jukdo market of Pohang. To identify the strains isolated, they were tested by examining their cell morphologies, gram-staining, catalase activity, arginine hydrolase activity, D-L lactate form and carbohydrate fermentation. According to the phenotypic characteristics, three strains were tent atively identified as Lactobacillus spp., ten were Enterococcus spp. (or Streptococcus spp., or Pediococcus spp.) and the rest were Leuconostoc spp. (or Weissella spp.). Five strains among 17 were chosen by preliminary bacteriocin activity test. Four bacterial strains which inhibited both indicator microorganisms were identified by 16S rRNA sequencing. The results are as follows; Leuconostoc mesenteroides (HK 4), Leuconostoc mesenteroides (HK 5), Leuconostoc mesenteroides(HK 11), Streptococcus salivarius(HK 8). In order to check LAB which are showing a high survival rate in gut, we investigated three strains inhibiting both indicator microorganisms in artificial gastric acid and bile juice -all except HK8. The three strains mentioned above grew in extreme low acid conditions.

Gram-positive and gram-negative bacteria induce different patterns of cytokine production in human mononuclear cells irrespective of taxonomic relatedness.

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Skovbjerg, Susann; Martner, Anna; Hynsjö, Lars; Hessle, Christina; Olsen, Ingar; Dewhirst, Floyd E; Tham, Wilhelm; Wold, Agnes E

2010-01-01

Upon bacterial stimulation, tissue macrophages produce a variety of cytokines that orchestrate the immune response that clears the infection. We have shown that Gram-positives induce higher levels of interleukin-12 (IL-12), interferon-gamma (IFN-gamma), and tumor necrosis factor (TNF) from human peripheral blood mononuclear cells (PBMCs) than do Gram-negatives, which instead induce more of IL-6, IL-8, and IL-10. Here, we study whether these patterns follows or crosses taxonomic borders. PBMCs from blood donors were incubated with UV-inactivated bacteria representing 37 species from five phyla. IL-12, TNF, IL-1beta, IL-6, IL-8, and IL-10 were measured in the supernatants after 24 h and IFN-gamma after 5 days. Irrespective of phylogenetic position, Gram-positive bacteria induced much more IL-12 (nine times more on average) and IFN-gamma (seven times), more TNF (three times), and slightly more IL-1beta (1.5 times) than did Gram-negatives, which instead induced more IL-6 (1.5 times), IL-8 (1.9 times), and IL-10 (3.3 times) than did Gram-positives. A notable exception was the Gram-positive Listeria monocytogenes, which induced very little IL-12, IFN-gamma, and TNF. The results confirm the fundamental difference in innate immune responses to Gram-positive and Gram-negative bacteria, which crosses taxonomic borders and probably reflects differences in cell wall structure.

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

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Antonija Trontel

2011-01-01

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

Characterization of airag collected in Ulaanbaatar, Mongolia with emphasis on isolated lactic acid bacteria.

Science.gov (United States)

Choi, Suk-Ho

2016-01-01

Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

Bioengineered nisin A derivatives with enhanced activity against both Gram positive and Gram negative pathogens.

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Des Field

Full Text Available Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G, with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria.

Bioengineered Nisin A Derivatives with Enhanced Activity against Both Gram Positive and Gram Negative Pathogens

Science.gov (United States)

Field, Des; Begley, Maire; O’Connor, Paula M.; Daly, Karen M.; Hugenholtz, Floor; Cotter, Paul D.; Hill, Colin; Ross, R. Paul

2012-01-01

Nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. It is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. The discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. We screened a randomized bank of nisin A producers and identified a variant with a serine to glycine change at position 29 (S29G), with enhanced efficacy against S. aureus SA113. Using a site-saturation mutagenesis approach we generated three more derivatives (S29A, S29D and S29E) with enhanced activity against a range of Gram positive drug resistant clinical, veterinary and food pathogens. In addition, a number of the nisin S29 derivatives displayed superior antimicrobial activity to nisin A when assessed against a range of Gram negative food-associated pathogens, including E. coli, Salmonella enterica serovar Typhimurium and Cronobacter sakazakii. This is the first report of derivatives of nisin, or indeed any lantibiotic, with enhanced antimicrobial activity against both Gram positive and Gram negative bacteria. PMID:23056510

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

Science.gov (United States)

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

2011-11-15

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

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

Science.gov (United States)

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

2017-11-27

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

10-oxo-12(Z)-octadecenoic acid, a linoleic acid metabolite produced by gut lactic acid bacteria, potently activates PPARγ and stimulates adipogenesis

Energy Technology Data Exchange (ETDEWEB)

Goto, Tsuyoshi, E-mail: tgoto@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University (Japan); Kim, Young-Il; Furuzono, Tomoya [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Takahashi, Nobuyuki [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University (Japan); Yamakuni, Kanae; Yang, Ha-Eun; Li, Yongjia [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Ohue, Ryuji [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Research Unit for Physiological Chemistry, The Center for the Promotion of Interdisciplinary Education and Research, Kyoto University (Japan); Nomura, Wataru [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji 611-0011 (Japan); Sugawara, Tatsuya [Laboratory of Marine Bioproducts Technology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502 (Japan); Yu, Rina [Department of Food Science and Nutrition, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Kitamura, Nahoko [Laboratory of Fermentation Physiology and Applied Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502 (Japan); and others

2015-04-17

Our previous study has shown that gut lactic acid bacteria generate various kinds of fatty acids from polyunsaturated fatty acids such as linoleic acid (LA). In this study, we investigated the effects of LA and LA-derived fatty acids on the activation of peroxisome proliferator-activated receptors (PPARs) which regulate whole-body energy metabolism. None of the fatty acids activated PPARδ, whereas almost all activated PPARα in luciferase assays. Two fatty acids potently activated PPARγ, a master regulator of adipocyte differentiation, with 10-oxo-12(Z)-octadecenoic acid (KetoA) having the most potency. In 3T3-L1 cells, KetoA induced adipocyte differentiation via the activation of PPARγ, and increased adiponectin production and insulin-stimulated glucose uptake. These findings suggest that fatty acids, including KetoA, generated in gut by lactic acid bacteria may be involved in the regulation of host energy metabolism. - Highlights: • Most LA-derived fatty acids from gut lactic acid bacteria potently activated PPARα. • Among tested fatty acids, KetoA and KetoC significantly activated PPARγ. • KetoA induced adipocyte differentiation via the activation of PPARγ. • KetoA enhanced adiponectin production and glucose uptake during adipogenesis.

10-oxo-12(Z)-octadecenoic acid, a linoleic acid metabolite produced by gut lactic acid bacteria, potently activates PPARγ and stimulates adipogenesis

International Nuclear Information System (INIS)

Goto, Tsuyoshi; Kim, Young-Il; Furuzono, Tomoya; Takahashi, Nobuyuki; Yamakuni, Kanae; Yang, Ha-Eun; Li, Yongjia; Ohue, Ryuji; Nomura, Wataru; Sugawara, Tatsuya; Yu, Rina; Kitamura, Nahoko

2015-01-01

Our previous study has shown that gut lactic acid bacteria generate various kinds of fatty acids from polyunsaturated fatty acids such as linoleic acid (LA). In this study, we investigated the effects of LA and LA-derived fatty acids on the activation of peroxisome proliferator-activated receptors (PPARs) which regulate whole-body energy metabolism. None of the fatty acids activated PPARδ, whereas almost all activated PPARα in luciferase assays. Two fatty acids potently activated PPARγ, a master regulator of adipocyte differentiation, with 10-oxo-12(Z)-octadecenoic acid (KetoA) having the most potency. In 3T3-L1 cells, KetoA induced adipocyte differentiation via the activation of PPARγ, and increased adiponectin production and insulin-stimulated glucose uptake. These findings suggest that fatty acids, including KetoA, generated in gut by lactic acid bacteria may be involved in the regulation of host energy metabolism. - Highlights: • Most LA-derived fatty acids from gut lactic acid bacteria potently activated PPARα. • Among tested fatty acids, KetoA and KetoC significantly activated PPARγ. • KetoA induced adipocyte differentiation via the activation of PPARγ. • KetoA enhanced adiponectin production and glucose uptake during adipogenesis

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

Science.gov (United States)

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

2017-03-01

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

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...

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

Science.gov (United States)

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

2012-07-01

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

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

International Nuclear Information System (INIS)

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

2012-01-01

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

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

Lactobacilli inactivate Chlamydia trachomatis through lactic acid but not H2O2.

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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

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

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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

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

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

2013-10-01

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

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

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

2018-02-16

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

Impact of lactic Acid bacteria on dendritic cells from allergic patients in an experimental model of intestinal epithelium.

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Ratajczak, Céline; Duez, Catherine; Grangette, Corinne; Pochard, Pierre; Tonnel, André-Bernard; Pestel, Joël

2007-01-01

Lactic acid bacteria (LAB) are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC) by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393) on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase) and increased their interleukin (IL)-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4(+) T cells to produce more interferon-gamma than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction.

Impact of Lactic Acid Bacteria on Dendritic Cells from Allergic Patients in an Experimental Model of Intestinal Epithelium

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Céline Ratajczak

2007-01-01

Full Text Available Lactic acid bacteria (LAB are Gram positive nonpathogenic commensal organisms present in human gastrointestinal tract. In vivo, LAB are separated from antigen-presenting cells such as dendritic cells (DC by the intestinal epithelial barrier. In this study, the impact of one LAB strain (Lactobacillus casei ATCC393 on human monocyte-derived DC from allergic and healthy donors was assessed by using a polarized epithelium model. Confocal and flow cytometer analyses showed that immature DC efficiently captured FITC-labelled L. casei through the epithelial layer. After interaction with L. casei, DC acquired a partial maturation status (i.e., CD86 and CD54 increase and increased their interleukin (IL-10 and IL-12 production. Interestingly, after activation by L. casei in the presence of experimental epithelium, DC from allergic patients instructed autologous naïve CD4+ T cells to produce more interferon-γ than without the epithelium. Thus by modulating human DC reactivity, LAB and intestinal epithelium might modify T cell immune response and regulate the development of allergic reaction.

Poly(Lactic Acid) Based Flexible Films

OpenAIRE

Fathilah binti Ali; Jamarosliza Jamaluddin; Arun Kumar Upadhyay

2014-01-01

Poly(lactic acid) (PLA) is a biodegradable polymer which has good mechanical properties, however, its brittleness limits its usage especially in packaging materials. Therefore, in this work, PLA based polyurethane films were prepared by synthesizing with different types of isocyanates; methylene diisocyanate (MDI) and hexamethylene diisocyanates (HDI). For this purpose, PLA based polyurethane must have good strength and flexibility. Therefore, polycaprolactone which has b...

Probiotic potential of noni juice fermented with lactic acid bacteria and bifidobacteria.

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Wang, Chung-Yi; Ng, Chang-Chai; Su, Hsuan; Tzeng, Wen-Sheng; Shyu, Yuan-Tay

2009-01-01

The present study assesses the feasibility of noni as a raw substrate for the production of probiotic noni juice by lactic acid bacteria (Lactobacilluscasei and Lactobacillus plantarum) and bifidobacteria (Bifidobacteriumlongum). Changes in pH, acidity, sugar content, cell survival and antioxidant properties during fermentation were monitored. All tested strains grew well on noni juice, reaching nearly 10⁹ colony-forming units/ml after 48 h fermentation. L.casei produced less lactic acid than B.longum and L. plantarum. After 4 weeks of cold storage at 4°C, B.longum and L. plantarum survived under low-pH conditions in fermented noni juice. In contrast, L.casei exhibited no cell viability after 3 weeks. Moreover, noni juice fermented with B.longum had a high antioxidant capacity that did not differ significantly (P <0.05) from that of lactic acid bacteria. Finally, we found that B.longum and L. plantarum are optimal probiotics for fermentation with noni juice.

original article antimicrobial susceptibility pattern of lactic acid

African Journals Online (AJOL)

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All the 57 tested lactic acid bacteria isolates were sensitive to Pencillin G (Pen, 10units), and ... resistance genes for Penicillin G and Erythromycin as indicated by the sensitivity of isolates. .... Antibiotic Susceptibility Test: The LAB isolates were ...

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

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Aldunate, Muriel; Srbinovski, Daniela; Hearps, Anna C.; Latham, Catherine F.; Ramsland, Paul A.; Gugasyan, Raffi; Cone, Richard A.; Tachedjian, Gilda

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 (BV), a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate, and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs) including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV) or dysbiosis (BV), their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs. PMID:26082720

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis

Directory of Open Access Journals (Sweden)

Muriel eAldunate

2015-06-01

Full Text Available 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 (BV, a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV or dysbiosis (BV, their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs.

Antimicrobial and immune modulatory effects of lactic acid and short chain fatty acids produced by vaginal microbiota associated with eubiosis and bacterial vaginosis.

Science.gov (United States)

Aldunate, Muriel; Srbinovski, Daniela; Hearps, Anna C; Latham, Catherine F; Ramsland, Paul A; Gugasyan, Raffi; Cone, Richard A; Tachedjian, Gilda

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 (BV), a dysbiosis of the vaginal microbiota, is characterized by decreased lactic acid-producing microbiota and increased diverse anaerobic bacteria accompanied by an elevated pH>4.5. BV is also characterized by a dramatic loss of lactic acid and greater concentrations of mixed SCFAs including acetate, propionate, butyrate, and succinate. Notably women with lactic acid-producing microbiota have more favorable reproductive and sexual health outcomes compared to women with BV. Regarding the latter, BV is associated with increased susceptibility to sexually transmitted infections (STIs) including HIV. In vitro studies demonstrate that lactic acid produced by vaginal microbiota has microbicidal and virucidal activities that may protect against STIs and endogenous opportunistic bacteria as well as immune modulatory properties that require further characterization with regard to their effects on the vaginal mucosa. In contrast, BV-associated SCFAs have far less antimicrobial activity with the potential to contribute to a pro-inflammatory vaginal environment. Here we review the composition of lactic acid and SCFAs in respective states of eubiosis (non-BV) or dysbiosis (BV), their effects on susceptibility to bacterial/viral STIs and whether they have inherent microbicidal/virucidal and immune modulatory properties. We also explore their potential as biomarkers for the presence and/or increased susceptibility to STIs.

Preservation of acidified cucumbers with a natural preservative combination of fumaric acid and allyl isothiocyanate that target lactic acid bacteria and yeasts

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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...

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

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

2015-01-01

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

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

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

2010-11-01

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

Characterization of airag collected in Ulaanbaatar, Mongolia with emphasis on isolated lactic acid bacteria

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Suk-Ho Choi

2016-03-01

Full Text Available Abstract Background Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares’ milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Methods Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Results Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10–3.36 % lactose, 1.44–2.33 % ethyl alcohol, 1.08–1.62 % lactic acid and 0.12–0.22 % acetic acid. Lactobacillus (L. helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Conclusion Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares’ milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

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

Production of l(+)-lactic acid from acid pretreated sugarcane bagasse using Bacillus coagulans DSM2314 in a simultaneous saccharification and fermentation strategy.

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van der Pol, Edwin C; Eggink, Gerrit; Weusthuis, Ruud A

2016-01-01

Sugars derived from lignocellulose-rich sugarcane bagasse can be used as feedstock for production of l(+)-lactic acid, a precursor for renewable bioplastics. In our research, acid-pretreated bagasse was hydrolysed with the enzyme cocktail GC220 and fermented by the moderate thermophilic bacterium Bacillus coagulans DSM2314. Saccharification and fermentation were performed simultaneously (SSF), adding acid-pretreated bagasse either in one batch or in two stages. SSF was performed at low enzyme dosages of 10.5-15.8 FPU/g DW bagasse. The first batch SSF resulted in an average productivity of 0.78 g/l/h, which is not sufficient to compete with lactic acid production processes using high-grade sugars. Addition of 1 g/l furfural to precultures can increase B. coagulans resistance towards by-products present in pretreated lignocellulose. Using furfural-containing precultures, productivity increased to 0.92 g/l/h, with a total lactic acid production of 91.7 g in a 1-l reactor containing 20% W/W DW bagasse. To increase sugar concentrations, bagasse was solubilized with a liquid fraction, obtained directly after acid pretreatment. Solubilizing the bagasse fibres with water increased the average productivity to 1.14 g/l/h, with a total lactic acid production of 84.2 g in a 1-l reactor. Addition of bagasse in two stages reduced viscosity during SSF, resulting in an average productivity in the first 23 h of 2.54 g/l/h, similar to productivities obtained in fermentations using high-grade sugars. Due to fast accumulation of lactic acid, enzyme activity was repressed during two-stage SSF, resulting in a decrease in productivity and a slightly lower total lactic acid production of 75.6 g. In this study, it is shown that an adequate production of lactic acid from lignocellulose was successfully accomplished by a two-stage SSF process, which combines acid-pretreated bagasse, B. coagulans precultivated in the presence of furfural as microorganism, and GC220 as enzyme

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

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

2017-08-01

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

Prolonged local anesthetic action through slow release from poly (lactic acid co castor oil).

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Sokolsky-Papkov, Marina; Golovanevski, Ludmila; Domb, Abraham J; Weiniger, Carolyn F

2009-01-01

To evaluate a new formulation of bupivacaine loaded in an injectable fatty acid based biodegradable polymer poly(lactic acid co castor oil) in prolonging motor and sensory block when injected locally. The polyesters were synthesized from DL: -lactic acid and castor oil with feed ratio of 4:6 and 3:7 w/w. Bupivacaine was dispersed in poly(fatty ester) liquid and tested for drug release in vitro. The polymer p(DLLA:CO) 3:7 loaded with 10% bupivacaine was injected through a 22G needle close to the sciatic nerve of ICR mice and the duration of sensory and motor nerve blockade was measured. The DL: -lactic acid co castor oil p(DLLA:CO) 3:7 released 65% of the incorporated bupivacaine during 1 week in vitro. Single injection of 10% bupivacaine loaded into this polymer caused motor block that lasted 24 h and sensory block that lasted 48 h. Previously we developed a ricinoleic acid based polymer with incorporated bupivacaine which prolonged anesthesia to 30 h. The new polymer poly(lactic acid co castor oil) 3:7 provides slow release of effective doses of the incorporated local anesthetic agent and prolongs anesthesia to 48 h.

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

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Witkin, Steven S

2018-05-01

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

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

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Zhang, Yixing; Vadlani, Praveen V

2015-06-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-07-01

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

Dynamic modeling of lactic acid fermentation metabolism with Lactococcus lactis.

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Oh, Euhlim; Lu, Mingshou; Park, Changhun; Park, Changhun; Oh, Han Bin; Lee, Sang Yup; Lee, Jinwon

2011-02-01

A dynamic model of lactic acid fermentation using Lactococcus lactis was constructed, and a metabolic flux analysis (MFA) and metabolic control analysis (MCA) were performed to reveal an intensive metabolic understanding of lactic acid bacteria (LAB). The parameter estimation was conducted with COPASI software to construct a more accurate metabolic model. The experimental data used in the parameter estimation were obtained from an LC-MS/ MS analysis and time-course simulation study. The MFA results were a reasonable explanation of the experimental data. Through the parameter estimation, the metabolic system of lactic acid bacteria can be thoroughly understood through comparisons with the original parameters. The coefficients derived from the MCA indicated that the reaction rate of L-lactate dehydrogenase was activated by fructose 1,6-bisphosphate and pyruvate, and pyruvate appeared to be a stronger activator of L-lactate dehydrogenase than fructose 1,6-bisphosphate. Additionally, pyruvate acted as an inhibitor to pyruvate kinase and the phosphotransferase system. Glucose 6-phosphate and phosphoenolpyruvate showed activation effects on pyruvate kinase. Hexose transporter was the strongest effector on the flux through L-lactate dehydrogenase. The concentration control coefficient (CCC) showed similar results to the flux control coefficient (FCC).

Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn

Science.gov (United States)

Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu

2017-10-01

A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.

Antimicrobial activities of lactic acid bacteria isolated from akamu ...

African Journals Online (AJOL)

The partially purified inhibitory compounds were screened by agar spot assay method for antagonistic ... The partially purified compounds exhibited strong activity against ... Keywords: Bacteriocins, lactic acid bacteria (LAB), target organisms, ...

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.

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

International Nuclear Information System (INIS)

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

1995-01-01

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

Thermal properties of poly (lactic acid)/milkweed composites

Science.gov (United States)

Currently, most polymer composites utilize petroleum-based materials that are non-degradable and difficult to recycle or incur substantial cost for disposal. Green composites can be used in nondurable limited applications. In order to determine the degree of compatibility between Poly (lactic Acid...

Lactic acid bacteria in a changing legislative environment

NARCIS (Netherlands)

Feord, J.

2002-01-01

The benefits of using lactic acid bacteria in the food chain, both through direct consumption and production of ingredients, are increasingly recognised by the food industry and consumers alike. The regulatory environment surrounding these products is diverse, covering foods and food ingredients,

Electrospinnability of poly lactic-co-glycolic acid (PLGA)

DEFF Research Database (Denmark)

Liu, Xiaoli; Baldursdottir, Stefania G.; Aho, Johanna

2017-01-01

PURPOSE: In this study, the electrospinnability of poly(lactic-co-glycolic acid) (PLGA) solutions was investigated, with a focus on understanding the influence of molecular weight of PLGA, solvent type and solvent composition on the physical properties of electrospun nanofibers. METHOD: Various s...

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

Science.gov (United States)

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

2012-12-01

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

Release of Polyphenols Is the Major Factor Influencing the Bioconversion of Rice Straw to Lactic Acid.

Science.gov (United States)

Chen, Xingxuan; Xue, Yiyun; Hu, Jiajun; Tsang, Yiu Fai; Gao, Min-Tian

2017-11-01

In this study, we found that p-coumaric acid (p-CA), ferulic acid (FA), and condensed tannins were released from rice straw during saccharification. The presence of polyphenols prolonged the lag phase and lowered the productivity of lactic acid. p-CA was identified as a key inhibitor. Tannins had a lower inhibitory effect than p-CA; FA had little inhibitory effect. Acid, alkaline, and ball milling pretreatments elicited different levels of polyphenol release from rice straw. Due to the different levels of polyphenol release in the pretreatment step, the enzymatic hydrolysates contained different concentrations of polyphenols. Compared with fermentation with a synthetic medium, fermentation with the hydrolysates of ball-milled rice straw provided much lower productivity and yield of lactic acid due to the presence of polyphenols. Removal of these compounds played an important role in lactic acid fermentation. When rice straw was alkaline pretreated, the hydrolysates contained few phenolic compounds, resulting in high productivity and yield of lactic acid (1.8 g/L/h and 26.7 g/100 g straw), which were comparable to those in a synthetic medium. This indicates that there is a correlation between removal of phenolic compounds and efficiency in lactic acid fermentation.

Antibacterial Activity of Silver-Graphene Quantum Dots Nanocomposites Against Gram-Positive and Gram-Negative Bacteria

Science.gov (United States)

Habiba, Khaled (Inventor); Makarov, Vladimir (Inventor); Weiner, Brad R (Inventor); Morell, Gerardo (Inventor)

2018-01-01

The invention provides a composite of silver nanoparticles decorated with graphene quantum dots (Ag-GQDs) using pulsed laser synthesis. The nanocomposites were functionalized with polyethylene glycol (PEG). A concentration of 150 .mu.g/mL of Ag-GQDs, a non-toxic level for human cells, exhibits strong antibacterial activity against both Gram-Positive and Gram-Negative Bacteria.

Characterization of Lactic Acid Bacteria (LAB) isolated from Indonesian shrimp paste (terasi)

Science.gov (United States)

Amalia, U.; Sumardianto; Agustini, T. W.

2018-02-01

Shrimp paste was one of fermented products, popular as a taste enhancer in many dishes. The processing of shrimp paste was natural fermentation, depends on shrimp it self and the presence of salt. The salt inhibits the growth of undesirable microorganism and allows the salt-tolerant lactic acid bacteria (LAB) to ferment the protein source to lactic acids. The objectives of this study were to characterize LAB isolated from Indonesian shrimp paste or "Terasi" with different times of fermentation (30, 60 and 90 days). Vitech analysis showed that there were four strains of the microorganism referred to as lactic acid bacteria (named: LABS1, LABS2, LABS3 and LABS4) with 95% sequence similarity. On the basis of biochemical, four isolates represented Lactobacillus, which the name Lactobacillus plantarum is proposed. L.plantarum was play role in resulting secondary metabolites, which gave umami flavor in shrimp paste.

Survival and Growth of Probiotic Lactic Acid Bacteria in Refrigerated Pickle Products.

Science.gov (United States)

Fan, Sicun; Breidt, Fred; Price, Robert; Pérez-Díaz, Ilenys

2017-01-01

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 in acidified vegetable products and to identify suitable cultures for probiotic brined vegetable products. We therefore developed assays to measure acid resistance of these cultures to lactic and acetic acids, which are present in pickled vegetable products. We used relatively high acid concentrations (compared to commercial products) of 360 mM lactic acid and 420 mM acetic acid to determine acid resistance with a 1 h treatment. Growth rates were measured in a cucumber juice medium at pH 5.3, 4.2, and 3.8, at 30 °C and 0% to 2% NaCl. Significant differences in acid resistance and growth rates were found among the 10 cultures. In general, the acid resistant strains had slower growth rates than the acid sensitive strains. Based on the acid resistance data, selected cultures were tested for long-term survival in a simulated acidified refrigerated cucumber product. We found that one of the most acid resistant strains (Lactobacillus casei) could survive for up to 63 d at 4 °C without significant loss of viability at 10 8 CFU/mL. These data may aid in the development of commercial probiotic refrigerated pickle products. © 2016 Institute of Food Technologists®.

Differentiation studies of predominant lactic acid bacteria isolated ...

African Journals Online (AJOL)

Twelve isolates known as weakly amylolytic lactic acid bacteria were isolated from different time during growol fermentation, a cassava based product from Indonesia. Differentiation tests of these strains were performed using molecular and phenotypic characterization. 16S subunit of the ribosomal RNA and phenylalanyl ...

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. Copyright © 2014 Elsevier Inc. All rights reserved.

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.

Molecular diversity of lactic acid bacteria on ileum broiler chicken fed by bran and bran fermentation

Science.gov (United States)

Baniyah, Laelatul; Nur Jannah, Siti; Rukmi, Isworo; Sugiharto

2018-05-01

Lactic Acid Bacteria (LAB) is a digestive tract microflora that have a positive role in poultry health. The number and diversity of LAB in the digestive tract affected by several factors, among them was the kind of feed. The purpose of this research was to know diversity of Lactic Acid Bacteria (LAB) ileum broiler’s after feeding with prebiotic bran and Rhizopus oryzae fermented bran which was added to commercial feed. As much as 15 broilers were used to determine the diversity of LAB. All broilers were fed using commercial feed. The control used commercial feed no addition of bran or fermented bran, and commercial feed with fermented bran and nonfermented bran were as a treatment. To determine the diversity of LAB, T-RFLP method was applied. The Hae III and Msp I were used as restriction enzymes. The number of phylotype, relative abundance, Shannon diversity index (H '), evenness (E), and Dominance (D) were examined. The results indicated that the addition of prebiotic bran on commercial feed showed a higher diversity of lactic acid bacteria on broiler’s ileum, compared with control and addition of Rhizopus oryzae fermented bran. LAB group that dominates in the ileum is Lactobacillus sp. and L. delbruecii subs bulgaricus.

Acid and bile tolerance of spore-forming lactic acid bacteria.

Science.gov (United States)

Hyronimus, B; Le Marrec, C; Sassi, A H; Deschamps, A

2000-11-01

Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of Sporolactobacillus, Bacillus laevolacticus, Bacillus racemilacticus and Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms, Bacillus laevolacticus DSM 6475 and all Sporolactobacillus strains tested except Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only Bacillus racemilacticus and Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).

Production of D-lactic acid from sugarcane bagasse using steam-explosion

Science.gov (United States)

Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi

2012-03-01

This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.

Production of D-lactic acid from sugarcane bagasse using steam-explosion

International Nuclear Information System (INIS)

Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi

2012-01-01

This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.

How bacterial cell division might cheat turgor pressure - a unified mechanism of septal division in Gram-positive and Gram-negative bacteria.

Science.gov (United States)

Erickson, Harold P

2017-08-01

An important question for bacterial cell division is how the invaginating septum can overcome the turgor force generated by the high osmolarity of the cytoplasm. I suggest that it may not need to. Several studies in Gram-negative bacteria have shown that the periplasm is isoosmolar with the cytoplasm. Indirect evidence suggests that this is also true for Gram-positive bacteria. In this case the invagination of the septum takes place within the uniformly high osmotic pressure environment, and does not have to fight turgor pressure. A related question is how the V-shaped constriction of Gram-negative bacteria relates to the plate-like septum of Gram-positive bacteria. I collected evidence that Gram-negative bacteria have a latent capability of forming plate-like septa, and present a model in which septal division is the basic mechanism in both Gram-positive and Gram-negative bacteria. © 2017 WILEY Periodicals, Inc.

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

Fermentation of Prefermented and Extruded Rice Flour by Lactic Acid Bacteria from Sikhae

DEFF Research Database (Denmark)

Lee, C. H.; Min, K. C.; Souane, M.

1992-01-01

of prefermentation of rice flour in solid-state with Bacillus laevolacticus and Saccharomyces cerevisiae, extrusion cooking and addition of soymilk as the substrate of lactic acid fermentation were tested. Extrusion cooking and prefermentation of rice increased the soluble solid and sugar contents before malt......The acid- and flavor-forming properties of Lactobacillus plantarum and Leuconostoc mesenteroides isolated from Sikhae, a Korean traditional lactic acid fermented fish product, were examined and compared to those of Lactobacillus casei and Lactococcus lactis subsp. diacetylactis DRC3. The effects...... digestion. The amount of sugar consumption during lactic fermentation varied with the type of bacteria. Leuconostoc mesenteroides(sikhae) and Lactobacillus plantarum(sikhae) increased up to 6 times of original cell number by 24 hrs of fermentation in rice + soymilk substrate, but Lactococcus lactis...

Amylolytic Enzymes Acquired from L-Lactic Acid Producing Enterococcus faecium K-1 and Improvement of Direct Lactic Acid Production from Cassava Starch.

Science.gov (United States)

Unban, Kridsada; Kanpiengjai, Apinun; Takata, Goro; Uechi, Keiko; Lee, Wen-Chien; Khanongnuch, Chartchai

2017-09-01

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112 kDa with optimal pH value and temperature measured of 7.0 and 40 °C, respectively. It was stable at a pH range of 6.0-7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba 2+ , Al 3+ , and Co 2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2 g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10 g/L cassava starch as the sole carbon source when cultivated at 37 °C for 48 h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150 g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.

Effect of lactic acid suppositories compared with oral metronidazole and placebo in bacterial vaginosis: a randomised clinical trial.

Science.gov (United States)

Boeke, A J; Dekker, J H; van Eijk, J T; Kostense, P J; Bezemer, P D

1993-01-01

OBJECTIVE--To compare the effect of lactic acid locally, metronidazole orally and placebo in women with bacterial vaginosis. DESIGN--Randomised clinical trial. SETTING--30 general practices in the Netherlands. PATIENTS--125 women consulting the general practitioner for symptomatic bacterial vaginosis. MAIN OUTCOME MEASURES--Duration of subjective symptoms, recurrence of symptoms, clinically diagnosed cure, adverse events. RESULTS--Survival analysis showed a significantly faster disappearance of symptoms in the metronidazole category compared with both lactic acid and placebo (p = 0.0005 metronidazole v placebo, p = 0.0002 metronidazole v lactic acid p = 0.6521 lactic acid v placebo [The stratified Mantel Cox test]). The median duration until absence of symptoms was 21 days for metronidazole and 80 days for placebo. Disappearance of symptoms did not occur in 50% of the lactic acid group in 90 days. Recurrence rates of symptoms were similar over the treatment categories (p = 0.13 metronidazole v placebo and p = 0.12 lactic acid v placebo). After 2 weeks cure rates (cure defined as less than three of four clinical criteria present) were 83%, 49% and 47% for metronidazole, lactic acid and placebo category respectively. At that time cure rates (cure defined as none of three clinical criteria present) were 10%, 0% and 3%. After four weeks and three months these figures were: 55%, 20%, 20% and 64%, 28%, 28%. No differences in adverse events were found between the three interventions. CONCLUSIONS--Lactic acid suppositories are ineffective, metronidazole capsules are effective on signs and symptoms in bacterial vaginosis. A considerable proportion of the patients recover without active medication. PMID:8244360

Lactic acid bacteria population dynamics during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine.

Science.gov (United States)

Pardali, Eleni; Paramithiotis, Spiros; Papadelli, Marina; Mataragas, Marios; Drosinos, Eleftherios H

2017-06-01

The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30 °C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.

Biotechnological conversion of spent coffee grounds into lactic acid.

Science.gov (United States)

Hudeckova, H; Neureiter, M; Obruca, S; Frühauf, S; Marova, I

2018-04-01

This work investigates the potential bioconversion of spent coffee grounds (SCG) into lactic acid (LA). SCG were hydrolysed by a combination of dilute acid treatment and subsequent application of cellulase. The SCG hydrolysate contained a considerable amount of reducing sugars (9·02 ± 0·03 g l -1 , glucose; 26·49 ± 0·10 g l -1 galactose and 2·81 ± 0·07 g l -1 arabinose) and it was used as a substrate for culturing several lactic acid bacteria (LAB) and LA-producing Bacillus coagulans. Among the screened micro-organisms, Lactobacillus rhamnosus CCM 1825 was identified as the most promising producer of LA on a SCG hydrolysate. Despite the inhibitory effect exerted by furfural and phenolic compounds in the medium, reasonably high LA concentrations (25·69 ± 1·45 g l -1 ) and yields (98%) were gained. Therefore, it could be demonstrated that SCG is a promising raw material for the production of LA and could serve as a feedstock for the sustainable large-scale production of LA. Spent coffee grounds (SCG) represent solid waste generated in millions of tonnes by coffee-processing industries. Their disposal represents a serious environmental problem; however, SCG could be valorized within a biorefinery concept yielding various valuable products. Herein, we suggest that SCG can be used as a complex carbon source for the lactic acid production. © 2018 The Society for Applied Microbiology.

Effect of different fermentation parameters on L-lactic acid production from liquid distillery stillage.

Science.gov (United States)

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

2012-09-15

Expansion of lactic acid applications, predominantly for the preparation of biodegradable polymers increased the research interest for new, economically favourable production processes. Liquid stillage from bioethanol production can be an inexpensive, valuable source of nutrients for growth of lactic acid bacteria. Utilisation of residual biomass with spent fermentation media as a functional animal feed can greatly influence the process value and its ecological aspect. In this paper, the kinetics of lactic acid and biomass production on liquid stillage by Lactobacillus rhamnosus ATCC 7469 was studied. In addition, the impact of temperature, inoculum concentration, shaking and pH control by addition of CaCO(3) was evaluated. Maximal lactic acid yield of 73.4%, as well as high biomass production (3×10(8) CFU ml(-1)) were achieved under selected conditions (41°C, 5% (v/v) of inoculum, 1% (w/v) of CaCO(3), initial pH of 6.5 and shaking rate of 90 rpm). These results were achieved without supplementation of the stillage with nitrogen or mineral sources. Copyright © 2012 Elsevier Ltd. All rights reserved.

RNases and Helicases in Gram-Positive Bacteria.

Science.gov (United States)

Durand, Sylvain; Condon, Ciaran

2018-04-01

RNases are key enzymes involved in RNA maturation and degradation. Although they play a crucial role in all domains of life, bacteria, archaea, and eukaryotes have evolved with their own sets of RNases and proteins modulating their activities. In bacteria, these enzymes allow modulation of gene expression to adapt to rapidly changing environments. Today, >20 RNases have been identified in both Escherichia coli and Bacillus subtilis , the paradigms of the Gram-negative and Gram-positive bacteria, respectively. However, only a handful of these enzymes are common to these two organisms and some of them are essential to only one. Moreover, although sets of RNases can be very similar in closely related bacteria such as the Firmicutes Staphylococcus aureus and B. subtilis , the relative importance of individual enzymes in posttranscriptional regulation in these organisms varies. In this review, we detail the role of the main RNases involved in RNA maturation and degradation in Gram-positive bacteria, with an emphasis on the roles of RNase J1, RNase III, and RNase Y. We also discuss how other proteins such as helicases can modulate the RNA-degradation activities of these enzymes.

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

2017-09-01

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.

Utilization of Encapsulated CaCO_3 in Liquid Core Capsules for Improving Lactic Acid Fermentation

International Nuclear Information System (INIS)

Boon-Beng, Lee; Nurul Ainina Zulkifli

2016-01-01

Lactic acid bacteria (LAB) have been used for food fermentation due to its fermentative ability to improve and enhance the quality of the end food products. However, the performance of LAB is affected as fermentation time elapsed because the microbial growth is inhibited by its end product, for example lactic acid. In this study, a new approach was introduced to reduce the product inhibition effect using CaCO_3 which is encapsulated in spherical liquid core capsules of diameter 3.5 mm and 3.6 mm produced through extrusion dripping method. The results showed that the pH and lactic acid concentration of LAB fermentation was well maintained by the capsules. The results of the fermentation conducted to control pH and lactic acid concentration using the capsules were better than those of the control set and comparable with that of the free CaCO_3 set. In addition, the viable cell concentration of L. casei shirota was high at the end of fermentation when the fermentation was conducted using the capsules. The results of this study suggested that the capsules have high potential to be applied for pH and lactic acid level control in LAB fermentation for various productions. (author)

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

Directory of Open Access Journals (Sweden)

Nursia Hassan

2016-03-01

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

Production of lactic acid from Starchy-based food substrates

African Journals Online (AJOL)

SARAH

2013-11-30

Nov 30, 2013 ... are rather costly. This necessitated ... found application in many industries and various commercial ... and Sharpe (MRS) agar for total lactic acid bacteria ..... An Economic ... of Enzymes and Microbial Technology, 26: 87-. 107.