• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.157-166
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• 2023

Three lactic acid bacteria (LAB) producing exopolysaccharides (EPSs) were isolated from Pa (green onion)-kimchi, and identified as Weissella confusa (SKP 173), Weissella cibaria (SKP 182), and Leuconostoc citreum (SKP 281), respectively by 16S rRNA gene sequencing. The yields of EPS were 21.27, 18.53, and 15.4 g/l for EPS from SKP 173, 182, and 281, respectively when grown in MRS broth containing sucrose (5%, w/v). Total sugar contents were 64.39, 62.84, and 65.16% (w/w) for EPS from SKP 173, 182, and 281, respectively while the protein contents were 0.33, 0.31, and 0.25% (w/w), respectively. EPSs from W. confusa SKP 173 and W. cibaria SKP 182 contained glucose only but EPS from L. citreum SKP 281 contained glucose and glucitol. Viscosities of the 2% (w/w) freeze-dried EPS solution were 9.60, 8.00, and 8.20 centipoise (cP) for EPS from SKP 173, 182, and 281, respectively. Viscosities of culture grown in MRS broth with 5% sucrose (no glucose) were 92.98, 57.19, and 18.8 cP, respectively. The average molecular weights of EPSs were larger than 2 × 10⁷ Da. Fourier transform infrared spectroscopy (FT-IR) analyses of EPSs showed typical carbohydrate peaks, suggesting that the EPSs consisted of pyranose saccharides with α-(1,6) and α-(1,3) glycosidic linkages. L. citreim SKP 281 was used as the starter for yogurt fermentation, and EPS production was confirmed.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.495-505
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• 1995

The purpose of this study was to identify the psychrotrophic lactic acid bacteria isolated from kimchi, a Korean traditional fermented vegetable food. Thirty isolates of psychrotrophic lactic acid bacteria were isolated randomly from kimchi-A and kimchi-B which were fermented at $5{\sim}7^{\circ}C$ for 20 days and 50 days, respectively. Among 30 isolates of lactic acid bacteria isolated from kimchi-A, 14 isolates were identified as Leuconostoc mesenteroides subsp. mesenteroides, 12 as Leuconostoc mesenteroides subsp. dextranicum and 4 as Lactobacillus bavaricus. Among 30 isolates isolated from kimchi-B, 20 isolates were identified as Lactobacillus bavaricus, 3 as Leuconostoc mesenteroides subsp. mesenteroides, 3 as Leuconostoc lactis, 2 as Leuconostoc paramesenteroides and 2 as Lactobacillus homohiochii. Though these strains were identified as above, there were many strains whose sugar fermenting patterns and $NH_3$ producing ability from arginine were inconsistent with those described in Bergey's Manual of Systematic Bacteriology, and some strains identified as Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc mesenteroides subsp. dextranicum even disclosed such contradictions as the comparisons of sugar fermenting patterns between the strains of different subspecies were much more coincident than those between the same subspecies. As there were difficulties in classifying these psychrotrophic lactic acid bacteria according to the current taxonomic system, further studies were needed to solve these problems.

• Journal of Life Science
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• v.31 no.5
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• pp.520-526
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• 2021

Microbial protein is one of the sources of protein in the rumen and can also be the source of glutamate production. Glutamic acid is used as fuel in the metabolic reaction in the body and the synthesis of all proteins for muscle and other cell components, and it is essential for proper immune function. Moreover, it is used as a surfactant, buffer, chelating agent, flavor enhancer, and culture medium, as well as in agriculture for such things as growth supplements. Glutamic acid is a substrate in the bioproduction of gamma-aminobutyric acid (GABA). This review provides insights into the role of glutamic acid and glutamic acid-producing microorganisms that contain the glutamate decarboxylase gene. These glutamic acid-producing microorganisms could be used in producing GABA, which has been known to regulate body temperature, increase DM intake and milk production, and improve milk composition. Most of these glutamic acid and GABA-producing microorganisms are lactic acid-producing bacteria (LAB), such as the Lactococcus, Lactobacillus, Enterococcus, and Streptococcus species. Through GABA synthesis, succinate can be produced. With the help of succinate dehydrogenase, propionate, and other metabolites can be produced from succinate. Furthermore, clostridia, such as Clostridium tetanomorphum and anaerobic micrococci, ferment glutamate and form acetate and butyrate during fermentation. Propionate and other metabolites can provide energy through conversion to blood glucose in the liver that is needed for the mammary system to produce lactose and live weight gain. Hence, health status and growth rates in ruminants can be improved through the use of these glutamic acid and/or GABA-producing microorganisms.

• Journal of Mushroom
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• v.11 no.4
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• pp.187-193
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• 2013

A galactose fermentation bacterium producing lactose from red seaweed, which was known well to compromise the galactose as main reducing sugar, was isolated from button mushroom bed in Buyeo-Gun, Chungchugnamdo province. The lactic acid bacteria MONGB-2 was identified as Lactobacillus paracasei subsp. tolerans by analysis of 16S rRNA gene sequence. When the production of lactic acid and acetic acid by L. paracasei MONGB-2 was investigated by HPLC analysis with various carbohydrates, the strain MONGB-2 efficiently convert the glucose and galactose to lactic acid with the yield of 18.86 g/L and 18.23 g/L, respectively and the ratio of lactic acid to total organic acids was 1.0 and 0.91 g/g for both substrates. However, in the case of acetic acid fermentation, other carbohydrates besides galactose and red seaweed hydrolysate could not be totally utilized as carbon sources for acetic acid production by the strain. The lactic acid production from glucose and galactose in the fermentation time courses was gradually enhanced upto 60 h fermentation and the maximal concentration reached to be 16-18 g/L from both substrates after 48 h of fermentation. The initial concentration of glucose and galactose were completely consumed within 36 h of fermentation, of which the growth of cell also was maximum level. In addition, the bioconversion of lactic acid from the red seaweed hydrolysate by L. paracasei MONGB-2 appeared to be about 20% levels of the initial substrates concentration and this results were entirely lower than those of galactose and glucose showed about 60% of conversion. The apparent results showed that L. paracasei MONGB-2 could produce the lactic acid with glucose as well as galactose by the homofermentation through EMP pathway.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.666-670
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• 2003

Strains producing the protease, which is essential for growth of lactic acid bacteria and fermented kimchi, were screened and identified. Among five types of selected pulmuone kimchis (Jeonlado kimchi, ripened kimchi, yeolmu kimchi, kakdugi, and baechu kimchi), nine strains of bacteria were screened and identified by whole cell protein pattern and API test. The nine strains consisted of one of Lactobacillus sp., one of Leuconostoc sp., six of Bacillus sp., and one of Brevibacillus sp. The protease activities of these strains were compared with known strains (Bac. subtilis KCCM 12248 and Bac. licheniformis KCCM 11851) producing protease. Among tested strains, K-2 (Brevibacillus sp.) showed the highest value (0.11 unit/mg) in protease activity.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.59-64
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• 2015

Lactic acid-producing bacteria such as Lactobacillus spp. function to ferment carbohydrates and produce ATP. Such Lactobacillus spp. are used for the production of commercial yogurts. Lactobacillus spp. are beneficial to the intestinal tract, and Lactobacillus acidophilus-containing yogurts have received considerable attention because of their preventive effects against early-stage cancer of the large intestine. In this study, lactic acid-producing bacteria were cultured from three different groups: commercial solid yogurt (for eating), commercial liquid yogurt (for drinking), and Lactobacillus acidophilus-containing yogurt. We first determined the optimum culture conditions for Lactobacillus spp. and then analyzed turbidity and pH in order to compare the growth abilities and lactic acid-production capacities among the groups. Finally, high-performance liquid chromatography was used to measure the lactic acid content in the culture supernatants, and the antibacterial activities against Staphylococcus aureus and Escherichia coli were compared among the three groups. The optimum culture conditions for Lactobacillus spp. were MRS medium at $25^{\circ}C$, for 24 h. The highest turbidity was found in L. acidophilus-containing yogurt, followed by liquid yogurt and solid yogurt. Similarly, the highest lactic acid production ability was found in L. acidophilus-containing yogurt, followed by liquid yogurt and solid yogurt. Culture supernatants from the three groups did not show any antibacterial activity towards S. aureus; however, supernatants derived from L. acidophilus-containing yogurt resulted in a 1.8 mm inhibitory zone against E. coli in a paper disk diffusion test. These results revealed the high level of lactic acid-production capacity and antibacterial activity in L. acidophilus-containing yogurt.

• Journal of Microbiology and Biotechnology
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• v.6 no.6
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• pp.461-467
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• 1996

Four strains of lactic acid bacteria (LAB), that lower the pH of sausage $\leq$ 4.2 within 24 h of incubation at $37^{\circ}C$, were screened from 57 bacteriocin producing LAB which were isolated from kajamie shikhae and natural fermented sausages. The proteinaceous nature of the bacteriocin was confirmed by losing antimicrobial activity after pronase treatment. Inhibitory activity against pathogens, times of bacteriocin production and sensory tests were compared between 4 isolates and 3 commercial starters. Especially, strain NFS #8-1, screened from natural fermented sausage and identified as Pediococcus acidilactici, antagonized a large number of foodborne pathogens including Listeria monocytogenes, Aeromonas hydrophila, Bacillus cereus, Clostridium perfringens, Salmonella typhimurium and Staphylococcus aureus. Production of bacteriocin by strain NFS #8-1 was early in the growth phase (mid log phase) and its sensory acceptance was high. The feasibility of using strain NFS #8-1 as a starter for the production of microbiologically safe fermented sausage is envisaged.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.936-942
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• 2002

When used in combination with organic acids, Pediococcus acidilactici K10 or its bacteriocin was effective in inhibiting Escherichia coli O157:H7 in vitro and in situ. P. acidilactici K10, a strain of bacteriocin-producing lactic acid bacteria (LAB), was previously isolated from kimchi in our laboratory, and the molecular weight of its bacteriocin was estimated to be around 4,500 Da by SDS-PAGE. Initially, P. acidilactici K10 and its bacteriocin could not inhibit E. coli O157:H7, when used alone. However, when they were used together with organic acids such as acetic, lactic, and succinic acids, they greatly inhibited E. coli O157:H7 in vitro. Based on these in vitro results, a real sample test with ground beef was conducted at $4^{\circ}C$ with acetic acid (0.25%) or lactic acid (0.35%) alone, and then in combination with P. acidilactici K10 (10^5 CFU/g of sample). Combined treatment of P. acidilactici K10 with lactic acid showed the most inhibitory effect: a 2.8-$log_{10}$-unit reduction of E. coli O157:H7 in ground beef during storage at $4^{\circ}C$. This result suggests that the combination of bacteriocin-producing P. acidilactici K10 and organic acids has great potential as a food biopreservative by inhibiting the growth of E. coli O157:H7.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.188-194
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• 2002

To study the effect of wheat bran and lactic acid producing bacteria (LAB) on the performance of calves, 20 crossbred male cattle calves (day old), distributed into two groups were fed on calf starters containing 50 or 0% maize grain, along with green berseem ad libitum and milk as per body weight. Each group was further divided into two sub groups and one subgroup of each group was supplemented with mixed culture of LAB (Lactobacillus acidophilus L. casei, L. Jugarti). Milk feeding was discontinued after 8 weeks of age. The addition of culture increased (p<0.05) DM intake in calves receiving grainless diet from eighth week to the thirteenth one. There was about 21% higher body weight gain and 14% lower feed : gain ratio in culture supplemented calves. DM digestibility was significantly lower (p<0.05) in calves getting grain without culture. The crude protein NDF and ADF digestibility was higher (p<0.05) in grainless than the grain fed group. No major change on rumen fermentation pattern among different treatments was found. The concentration of total volatile fatty acids (TVFA) and protozoa count was higher (p<0.05) in grain fed group. However, lactic acid concentration was higher and rumen pH was lower due to culture feeding. The incidence as well as severity of diarrhoea was reduced in culture supplemented group. The results indicate that crossbred calves can be reared successfully on grainless diet and berseen fodder. The performance of calves was also improved by LAB supplementation.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.258-267
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• 2019

The purpose of this study was to investigate the effect of lactic acid bacteria (LAB) on the growth and biogenic amines (BA) formation of Enterobacter aerogenes CIH05 in skim milk and soymilk. Lactobacillus acidophilus GK20, Lactobacillus paracasei GK74, and Lactobacillus plantarum GK81 isolated from mustard kimchi did not produce BA in the decarboxylation broth. L. paracasei GK74 exhibited the highest cell viability and antimicrobial compounds producing ability in fermented skim milk and soymilk samples, while the lowest producer was L. plantarum GK81. The production yield of lactic acid, hydrogen peroxide, and bacteriocin was dependent on the species of Lactobacillus and the type of culture medium. As LAB the number of viable cells of E. aerogenes CIH05 were higher in skim milk than in soymilk. When mixed culture with L. acidophilus GK20 and L. paracasei GK74 and treated with bacteriocin solution (300 AU/ml) obtained from these strains in milk media, the cell growth and cadaverine and histamine contents of E. aerogenes CIH05 were significantly (P < 0.05) lower than the respective values in control sample.