• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.11
• /
• pp.1872-1877
• /
• 2013

Lactic acid bacteria were selected on the basis of lactic acid producing ability from kimchi, a traditional Korean fermented food. Among the initial screening of over 150 strains selected from the sample, 27 strains were selected as lactic acid producing bacteria, and 4 strains were finally selected based on their ability to produce relatively high levels of lactic acid. The four strains were identified as Lactobacillus (L.) plantarum Gk04, Pediococcus pentosaceus Gk07, L. brevis Gk35 and L. curvatus Gk36 by the conventional morphological, cultural, physiological and biochemical characteristics, as well as by 16S rRNA sequence analysis. Among the identified lactic acid bacteria, L. curvatus Gk36 was used for soymilk fermentation. The viable cell counts and acidity values measured for the L. curvatus Gk36 were comparable to the commmercial L. acidopillus. Thus, the L. curvatus Gk36 is a potential probiotic strain to prepare fermented soy products, such as kephir, yogurt, tempeh and soy sauce.

• Microbiology and Biotechnology Letters
• /
• v.36 no.4
• /
• pp.247-259
• /
• 2008

Terminal-restriction fragment length polymorphism (T-RFLP) analysis, one of rapid culture-independent microbial community analysis methods, was used to determine the lactic acid bacterial complexity and dynamics during kimchi fermentation at $15^{\circ}C$ and $4^{\circ}C$. At both temperatures, the common presence of Leuconostoc mesenteroides, Lc. inhae, Lc. kimchi, Weissella koreensis, W. cibaria, Lactobacillus sakei, Lb. curvatus, Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was predicted. Lc. citreum and Enterococcus faecalis were detected at $15^{\circ}C$ and $4^{\circ}C$, respectively. W. koreensis predominated during the mid stage of kimchi fermentation whereas lactobacilli were dominants during later stage. Lb. sakei and Lb. curvatus became dominants regardless of fermentation temperature but the growth of Lb. plantarum, Lb. paraplantarum, Lb. pentosus, and Lb. brevis was restricted at psychrophilic temperature. Some species of leuconostocs were maintained until the later stage of kimchi fermentation.

• Food Science of Animal Resources
• /
• v.30 no.5
• /
• pp.795-803
• /
• 2010

A DF01 strain that inhibits tyramine-producing Lactobacillus curvatus KFRI 166 was isolated from Dongchimi, a traditional Korean fermented vegetable, and identified as Lactobacillus brevis by biochemical analysis and reverse transcriptase sequencing of 16S rRNA. The antimicrobial compound produced by L. brevis DF01 was secreted at a maximum level of 640 AU/mL in late exponential phase in MRS broth, and its activity remained constant during stationary phase. The activity of bacteriocin DF01 was totally inactivated by $\alpha$-chymotrypsin, pronase E, proteinase K, trypsin, and $\alpha$-amylase, but not by catalase, which indicates the compound was glycoprotein in nature. The activity was not affected by pH changes ranging from 2 to 12 or heat treatment (60, 80, and $100^{\circ}C$ for 30 min), but was reduced after autoclaving. Bacteriocin DF01 had bacteriolytic activity and a molecular weight of approximately 8.2 kDa, as shown by tricine-SDS-PAGE analysis. Therefore, bacteriocin DF01 can be used in the manufacture of fermented meat products due to its inhibition of tyramine-producing L. curvatus and non-inhibition of L. sake, which is used as a starter culture for meat fermentation.

• Food Science and Preservation
• /
• v.14 no.2
• /
• pp.188-193
• /
• 2007

The purpose of this study was to isolate lactic acid bacteria, useful in the fermentation industry from Hahyangju Nuruk. Five strains were isolated, and identified as Lactobacillus based on growth inhibition by 10% (v/v) alcohol at pH 4.0. Isolated strains were identified to species, and named Lactobacillus plantarum L-3, L. sakei L-10, and L. curvatus strains L-8, L-11, and L-12. Morphological characteristics, physiological data, carbohydrate fermentation patterns, and 16S rRNA sequence data, were all used to characterize the bacterial isolates. L. plantarum L-3 showed the highest lactic acid productivity of all isolates, but grew only poony in the presence of 10% (v/v) alcohol at pH 4.0. The other strains exhibited lower lactic acid productivity than did L. plantarum L-3 and did not grow in the presence of 10% (v/v) alcohol at pH 4.0. The optimal temperature and pH for lactic acid production were $30^{\circ}C$ and pH 6.0 7.0, respectively. The lactic acid productivity of L. plantarum L-3, L. sakei L-10 and the three L. curvatus strains L-8, L-11, and L-12 were (% v/v of culture supematant) 1.55, 1.0, 1.06, 1.0, and 0.99, respectively, at $30^{\circ}C$ and pH 6.0. While L. plantarum L-3 suffered growth inhibition in the presence of 10% (v/v) alcohol, growth of the other strains was inhibited at 8% (v/v) alcohol.

• Korean Journal of Organic Agriculture
• /
• v.22 no.4
• /
• pp.801-813
• /
• 2014

A study was conducted to improve the biological activity of two medicinal plants, Eucommia ulmoides Oliv. and Glycyrrhiza uralensis, by fermentation. The biological activity was assessed by determining antibacterial, antioxidant and antimethanogenic properties. Fermentation was achieved by adding the plant materials in MRS broth at 10% (w/v) and different starter cultures at 1% (v/v). Condition for fermentation were incubation temperature of $30^{\circ}C$ and agitation at 150 rpm for 48 h. Six starter cultures, Weissella confusa NJ28 (Genbank accession number KJ914897), Weissella cibaria NJ33 (Genbank accession number KJ914898), Lactobacillus curvatus NJ40 (Genbank accession number KJ914899), Lactobacillus brevis NJ42 (Genbank accession number KJ914900), Lactobacillus plantarum NJ45 (Genbank accession number KJ914901) and Lactobacillus sakei NJ48 (Genbank accession number KJ914902) were used. Antibacterial activity was observed in L. curvatus NJ40 and L. plantarum NJ45 only as opposed to other treatments, including the non-fermented groups, which showed no antibacterial activity. Both plants showed antioxidant activity, although E. ulmoides Oliv. had lower activity than G. uralensis. However, fermentation by all strains significantly improved (p<0.05), antioxidant activity in both plants compared to non-fermented treatment. Six treatments were based on antibacterial activity results, selected for in vitro rumen fermentation; 1) non-fermented E. ulmoides, 2) fermented E. ulmoides NJ40, 3) fermented E. ulmoides NJ45, 4) non-fermented G. uralensis, 5) fermented G. uralensis NJ40, 6) fermented G. uralensis NJ45. A negative control was also added, making a total of 7 treatments for the in vitro experiment. Medicinal plant-based treatments significantly improved (p<0.05) total volatile fatty acid (VFA) concentration. Significant methane reduction per mol of VFA were observed in G. uralensis (p<0.05). Based on the present study, fermentation improves the biological activity of E. ulmoides Oliv. and G. uralensis. Fermented G. uralensis could also be applied as an enteric methane mitigating agent in ruminant animals.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.2
• /
• pp.237-243
• /
• 2017

To investigate the effects of lactic acid bacteria (LAB), Lactobacillus sakei, Lactobacillus curvatus, and Lactobacillus brevis, commonly found in kimchi, on N-nitrosodimethylamine (NDMA) and its precursors such as nitrite, dimethylamine (DMA), nitrate, and biogenic amines, Baechu (Chinese cabbage) kimchi prepared with and without LAB and $NaNO_2$ was periodically monitored for 20 days to analyze concentrations of NDMA and its precursors. Control was amine and nitrite-rich kimchi. NDMA and its precursors were analyzed to determine differences in concentrations between LAB-fortified kimchi and the control. The amounts of NDMA, nitrite, DMA, and nitrate remaining in LAB-fortified kimchi were significantly reduced compared with those of control kimchi. In addition, biogenic amines were significantly lower in kimchi prepared with L. sakei, L. curvatus, and L. brevis. These results suggest that addition of LAB to the kimchi preparation would be a promising solution for production of NDMA-reduced kimchi.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.9
• /
• pp.1467-1474
• /
• 2013

To develop a starter culture system for the fermentation of mukeunji, we introduced lactic acid bacteria and yeast isolated from mukeunji into kimchi fermentation as a single or a mixed culture. On evaluating mukeunji flavor, we found that the mixed starter kimchi prepared with two strains, ML17 and MY7, gave the best sensory score. These strains were identified as Lactobacillus (Lb.) curvatus ML17 and Saccharomyces (S.) servazzii MY7 by molecular identification method. The fermentative characteristics of starter kimchi were investigated by measuring changes in the physicochemical and microfloral characteristics during the fermentation. The decrease in pH and increase in acidity in the starter kimchi were faster compared to respective values of control kimchi. There was a gradual decrease in hardness of starter kimchi, which was still slow compared to hardness decrease in control kimchi. Microbial analysis of starter kimchi revealed that Lb. curvatus ML17 and S. servazzii MY7 were the dominant organisms during the entire fermentation period. The lactic acid and citric acid contents of starter kimchi were higher than those of the control kimchi after 90 days of fermentation. By sensory evaluation, the starter kimchi scored higher in appearance, mukeunji flavor, sourness, carbonated flavor, savory taste, texture, and overall acceptability, but lower in off-flavor than the control kimchi.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.9
• /
• pp.1532-1536
• /
• 2015

To investigate the memory-enhancing effect of lactic acid bacteria, we selected the probiotic mixture KF, which consisted of Lactobacillus plantarum KY1032 and Lactobacillus curvatus HY7601 (1 × 10¹¹ CFU/g of each strain), and investigated its antilipidemic and memoryenhancing effects in aged Fischer 344 rats. KF (1 × 10¹⁰ CFU/rat/day), which was administered orally once a day (6 days per week) for 8 weeks, significantly inhibited age-dependent increases of blood triglyceride and reductions of HDL cholesterol (p < 0.05). KF restored agereduced spontaneous alternation in the Y-maze task to 94.4% of that seen in young rats (p < 0.05). KF treatment slightly, but not significantly, shortened the escape latency daily for 4 days. Oral administration of KF restored age-suppressed doublecortin and brain-derived neurotrophic factor expression in aged rats. Orally administered KF suppressed the expression of p16, p53, and cyclooxygenase-2, the phosphorylation of Akt and mTOR, and the activation of NF-κB in the hippocampus of the brain. These findings suggest that KF may ameliorate age-dependent memory deficit and lipidemia by inhibiting NF-κB activation.

• Journal of Applied Biological Chemistry
• /
• v.63 no.4
• /
• pp.375-385
• /
• 2020

The purpose of this study was to investigate the quality characteristics of kimchi prepared with a single starter culture of biogenic amines (BA)-forming lactic acid bacteria (LAB) or a combined starter cultures composed of BA-forming and BA-degrading LAB. As the fermentation proceeded, the lactic acid bacterial count, titratable acidity, and BA content in kimchi prepared with myeolchi-aekjeot were slightly higher than those of kimchi prepared with saeu-jeot. The amount and type of BA produced by LAB were mostly strain dependent rather than species specific. Among all of the isolated LAB strains, the highest levels of cadaverine, histamine, putrescine and tyramine were produced by Leuconostoc mesenteroides MBK32, Lactobacillus brevis MBK34, Lactobacillus curvatus MBK31 and Enterococcus faecalis SBK31, respectively. BA-forming and BA-degrading starter cultures played an important role in the growth rate and organic acid-producing ability of LAB in kimchi. Interestingly, BA contents in kimchi increased by adding single BA-forming LAB starter were effectively lowered by the mixed cultures with BA-degrading LAB.

• Mycobiology
• /
• v.44 no.4
• /
• pp.302-309
• /
• 2016

The role of lactic acid bacteria (LAB) in honey as antifungal activity has received little attention and their mechanism of inhibitory of fungi is not fully understood. In this study, LAB were isolated from honey samples from Malaysia, Libya, Saudi Arabia, and Yemen. Twenty-five isolates were confirmed LAB by catalase test and Gram staining, and were screened for antifungal activity. Four LAB showed inhibitory activity against Candida spp. using the dual agar overlay method. And they were identified as Lactobacillus plantarum HS isolated from Al-Seder honey, Lactobacillus curvatus HH isolated from Al-Hanon honey, Pediococcus acidilactici HC isolated from Tualang honey and Pediococcus pentosaceus HM isolated from Al-Maray honey by the 16S rDNA sequence. The growth of Candida glabrata ATCC 2001 was strongly inhibited (>15.0 mm) and (10~15 mm) by the isolates of L. curvatus HH and P. pentosaceus HM, respectively. The antifungal activity of the crude supernatant (cell free supernatant, CFS) was evaluated using well diffusion method. The CFS showed high antifungal activity against Candida spp. especially The CFS of L. curvatus HH was significantly (p < 0.05) inhibited growth of C. glabrata ATCC 2001, C. parapsilosis ATCC 2201, and C. tropicalis ATCC 750 with inhibitory zone 22.0, 15.6, and 14.7 mm, respectively. While CFS of P. pentosaceus HM was significantly (p < 0.05) effective against C. krusei, C. glabrata, and C. albicans with inhibition zone 17.2, 16.0, and 13.3 mm, respectively. The results indicated that LAB isolated from honey produced compounds which can be used to inhibit the growth of the pathogenic Candida species.