• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.298-303
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• 2021

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.602-609
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• 2015

In this study, for modernization of Korean traditional fermented milk, Tarak was made using four kinds of commercial Makgeolli based on the ancient cookbook Suwoonjabbang. Samples of Tarak were periodically collected during 24 h of fermentation at $37^{\circ}C$. After fermentation, changes in pH, titration acidity, and viscosity were analyzed. Fermentation metabolites, including organic acids and free sugars, were analyzed by HPLC. Numbers of yeast and lactic acid bacteria during 24 h of fermentation were measured. The pH of Tarak significantly decreased (P<0.01), whereas its acidity significantly increased (P<0.01) during fermentation. The viscosity increased during 8~24 h of fermentation until curd was separated in Tarak. The level of ethanol increased from 0.37~0.52 mg/mL to 0.51~0.71 mg/mL during 24 h of fermentation. Lactic acid and lactose were the major organic acid and free sugar in Tarak, respectively. The number of lactic acid bacteria increased from 5.23~6.25 log CFU/mL to 9.87~10.41 log CFU/mL at the beginning during 24 h of fermentation. The number of yeast increased from 5.14~6.47 log CFU/mL to 6.99~7.73 at the beginning during 24 h of fermentation at $37^{\circ}C$. The major strains of Tarak were Pediococcus acidilactici, Lactobacillus fermentun, Lactobacillus curvatus, and Saccharomyces cerevisiae. Therefore, we concluded that Tarak was a fermented milk by both lactic acid bacteria and yeast, which was similar to koumiss or kefir.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.350-356
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• 2011

The purpose of this study was to investigate changes in the contents of constituents in Sipjundaebo-tang (SJ) and its fermentations (FSJ) with 8 species of lactic acid bacteria. Eight strains of lactic acid bacteria, Lactobacillus casei KFRI129, L. plantarum KFRI 144, L. curvatus KFRI 166, L. hilgardii KFRI 229, L. delbruekil subsp. lactis KFRI 442, L. casei KFRI 692, L. gasseri KCTC 3163, and Bifidobacterium breve KFRI 744, were utilized for the fermentation of Sipjundaebo-tang. As a result we identified three constituents which increased and two constituents which decreased. The increased constituents were isolated by chromatographic techniques and then their structure elucidated using NMR and MS. The decreased constituents were confirmed by comparing standard compounds. These compounds were quantitatively analyzed using the HPLC/DAD system. The increased constituents were identified to be cinnamyl alcohol (1), liquiritigenin (3), and nodakenetin (5), while the decreased constituents were liquiritin (2) and nodakenin (4). Generally, liquiritin (2) and nodakenin (4) were noted as having decreased in fermented Sipjundaebo-tangs (FSJs), while cinnamyl alcohol (1), liquiritigenin (3), and nodakenetin (5) were seen to have increased. Sipjundaebo-tang fermented by L. plantarum KFRI144 exhibited the most remarkable changes in all of fermentations. The eight lactic acid bacteria all demonstrated differing decomposable rates on the five maker compounds in fermented Sipjundaebo-tang (FSJ).