• Journal of Dairy Science and Biotechnology
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• v.18 no.1
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• pp.47-60
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• 2000

Over decades of work, the probiotic research has grown rapidly with a number of new cultures, which is claimed a variety of benefit. However, many of the specific effects attributed to the ingestion of probiotics remain convoluted and scientifically unsubstantiated. Accordingly, the scientific community faces a greater challenge and must objectively seek cause and effect relationships for many potential and currently investigated probiotic species. Rational selection and design of probiotics remains an important challenge and will require a solid information about the physiology and genetics of candidate strains relevant to their intestinal roles, functional activities, and interaction of with other resident micro flora. As far as beneficial culture of lactic acid bacteria (LAB) is concerned, simple, cost-effective, and exact identification of candidate strains is of foremost importance among others. Until recently, the relatedness of bacterial isolates has been determined sorely by testing for one or several phenotyphic markers, using methods such as serotyping, phage-typing, biotyping, and so forth. However, there are problems in the use of many of these phenotype-based methods. In contrast, some of newer molecular typing methods involving the analysis of DNA offer many advantages over traditional techniques. These DNA-based methods have the greater discriminatory power than that of phenotypic procedures. This review focuses on the importance and the basis of molecular typing methods along with some considerations on de-sign and selection of probiotic culture for human consumption.

• Food Science and Preservation
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• v.15 no.3
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• pp.427-436
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• 2008

This research investigated the application of semi-dried red pepper in Kimchi manufactured using semi-dried red pepper with seed ratios of 20, 40, 60 or 80%. Among the treatments, there were no significant changes in pH, acidity and lactic acid bacterial cell counts during the fermentation period. Kimchi made with a higher pericarp ratio had higher levels of vitamin C, ASTA value and capsainoids during fermentation. The organic acid level showed no significant difference with the various semi-dried red pepper seed ratios, and during fermentation the malic and succinic acid levels decreased while the acetic and lactic acid levels increased. In a sensory evaluation, the overall acceptance was highest for the control group, but the acceptance of Kimchi prepared with semi-dried red pepper at a seed ratio lower than 20% was not significantly different.

• Food Science and Preservation
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• v.24 no.3
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• pp.387-393
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• 2017

The objective of this study was to investigate the effect of hot water extract of Welsh onion root (HEWO) on growth of lactic acid bacteria and fermentative characteristics of yogurt. The physiochemical characteristics of HEWO such as pH, soluble solid, reducing sugar, total polyphenol content and DPPH radical scavenging activity were studied. The lactic bacterial count in brain heart infusion (BHI) broth with HEWO was about 1 log cycle higher than in control for 24 h at $37^{\circ}C$. The pH of yogurt prepared with HEWO (WY100) and 50% HEWO (WY50) was gradually decreased significantly but increased the viscosity of yogurt with increasing HEWO concentration during fermentation. The viable cells of lactic acid bacteria after fermentation for 24 h were 8.03 (control), 8.77 (WY50), 8.84 (WY100) log CFU/mL, respectively. The DPPH radical scavenging activity of yogurt increased with increasing HEWO concentration. Sensory quality of yogurt prepared with HEWO was higher than that of control. The pH and lactic acid bacteria of all tested yogurts decreased during storage for 10 days at $4^{\circ}C$ but lactic bacterial count of yogurt prepared with HEWO maintained $10^8CFU/mL$ during storage. These results indicated the potential use of HEWO as a valuable resource to improve fermentation and functionality of yogurt.

• Journal of Microbiology and Biotechnology
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• v.24 no.10
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• pp.1438-1444
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• 2014

Lactic acid bacteria (LAB) are probiotics that provide numerous beneficial effects on the host body, especially on the intestine. Combining several strains of LAB, we prepared a formulation containing four different LAB and studied its anti-inflammatory activity both in vitro and in vivo. The formulation significantly reduced NO production from RAW 264.7 cells treated with bacterial lipopolysaccharide, indicating that the formulation might include anti-inflammatory activity. The formulation also suppressed inflammatory change induced by trinitrobenzene sulfonic acid (TNBS) in mice, where oral or rectal administration of the formulation protected the colon tissue from the damage by TNBS. Expressions of the IL-6 and FasL genes appeared to be down-regulated by the formulation in TNBS-treated colon tissues, suggesting that the suppression of those genes may be involved in the anti-inflammatory activity of the formulation.

• Journal of Microbiology and Biotechnology
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• v.28 no.5
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• pp.697-706
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• 2018

Lactobacillus pentosus K1-23 was selected from among 25 lactic acid bacterial strains owing to its high inhibitory activity against several pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, S. gallinarum, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium perfringens, and Listeria monocytogenes. Additionally, among 13 strains of Aureobasidium spp., A. pullulans NRRL 58012 was shown to produce the highest amount of ${\beta}$-glucan ($15.45{\pm}0.07%$) and was selected. Next, the optimal conditions for a solid-phase mixed culture with these two different microorganisms (one bacterium and one yeast) were determined. The optimal inoculum sizes for L. pentosus and A. pullulans were 1% and 5%, respectively. The appropriate inoculation time for L. pentosus K1-23 was 3 days after the inoculation of A. pullulans to initiate fermentation. The addition of 0.5% corn steep powder and 0.1% $FeSO_4$ to the basal medium resulted in the increased production of lactic acid bacterial cells and ${\beta}$-glucan. The following optimal conditions for solid-phase mixed culture were also statistically determined by using the response surface method: $37.84^{\circ}C$, pH 5.25, moisture content of 60.82%, and culture time of 6.08 days for L. pentosus; and $24.11^{\circ}C$, pH 5.65, moisture content of 60.08%, and culture time of 5.71 days for A. pullulans. Using the predicted optimal conditions, the experimental production values of L. pentosus cells and ${\beta}$-glucan were $3.15{\pm}0.10{\times}10^8CFU/g$ and $13.41{\pm}0.04%$, respectively. This mixed culture may function as a highly efficient antibiotic substitute based on the combined action of its anti-pathogenic bacterial and immune-enhancing activities.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.40-46
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• 2013

A variety of nuruk were collected from various provinces in Korea, and their microflora profiles were analyzed at the species level. A total of 42 nuruk samples were collected and when the viable cell numbers in these nuruk were enumerated, the average cell numbers of bacteria, fungi, yeast, and lactic acid bacteria from all nuruk were 7.21, 7.91, 3.49, and 4.88 log CFU/10 g, respectively. There were no significant differences in viable cell numbers of bacteria or fungi according to regions collected. Bacillus amyloliquefaciens and B. subtilis were the predominant bacterial strains in most samples. A significant portion, 13 out of 42 nuruk, contained foodborne pathogens such as B. cereus or Cronobacter sakazakii. There were various species of lactic acid bacteria such as Enterococcus faecium and Pediococcus pentosaceus in nuruk. It was unexpectedly found that only 13 among the 42 nuruk samples contained Aspergillus oryzae, the representative saccharifying fungi in makgeolli, whereas a fungi Lichtheimia corymbifera was widely distributed in nuruk. It was also found that Pichia jadinii was the predominant yeast strain in most nuruk, but the representative alcohol fermentation strain, Saccharomyces cerevisiae, was isolated from only 18 out of the 42 nuruk. These results suggested that a variety of species of fungi and yeast were distributed in nuruk and involved in the fermentation of makgeolli. In this study, a total of 64 bacterial species, 39 fugal species, and 15 yeast species were identified from nuruk. Among these strains, 37 bacterial species, 20 fungal species, and 8 yeast species were distributed less than 0.1%.

• Journal of Microbiology and Biotechnology
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• v.23 no.1
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• pp.76-84
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• 2013

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique followed by sequencing of the 16S rDNA fragments eluted from the bands of interest on denaturing gradient gels was used to monitor changes in the bacterial microflora of two commercial kimchi, salted cabbage, and ingredient mix samples during 30 days of fermentation at $4^{\circ}C$ and $10^{\circ}C$. Leuconostoc (Lc.) was the dominant lactic acid bacteria (LAB) over Lactobacillus (Lb.) species at $4^{\circ}C$. Weissella confusa was detected in the ingredient mix and also in kimchi samples throughout fermentation in both samples at $4^{\circ}C$ and $10^{\circ}C$. Lc. gelidum was detected as the dominant LAB at $4^{\circ}C$ in both samples. The temperature affected the LAB profile of kimchi by varing the pH, which was primarily caused by the temperature-dependent competition among different LAB species in kimchi. At $4^{\circ}C$, the sample variations in pH and titratable acidity were more conspicuous owing to the delayed growth of LAB. Temperature affected only initial decreases in pH and initial increases in viable cell counts, but affected both the initial increases and final values of titratable acidity. The initial microflora in the kimchi sample was probably determined by the microflora of the ingredient mix, not by that of the salted cabbage. The microbial distributions in the samples used in this study resembled across the different kimchi samples and the different fermentation temperatures as the numbers of LAB increased and titratable acidity decreased.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1248-1254
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• 2012

The effect of silage additives on ensiling characteristics and nutritive value of Napier grass (Pennisetum purpureum) silages was studied. Napier grass silages were made with no additive, fermented juice of epiphytic lactic acid bacteria (FJLB), molasses or cassava meal. The ensiling characteristics were determined by ensiling Napier grass silages in airtight plastic pouches for 2, 4, 7, 14, 21 and 45 d. The effect of Napier grass silages treated with these additives on voluntary feed intake, digestibility, rumen fermentation and microbial rumen fermentation was determined in 4 fistulated cows using $4{\times}4$ Latin square design. The pH value of the treated silages rapidly decreased, and reached to the lowest value within 7 d of the start of fermentation, as compared to the control. Lactic acid content of silages treated with FJLB was stable at 14 d of fermentation and constant until 45 d of ensiling. At 45 d of ensiling, neutral detergent fiber (NDF) and acid detergent fiber (ADF) of silage treated with cassava meal were significantly lower (p<0.05) than the others. In the feeding trial, the intake of silage increased (p<0.05) in the cow fed with the treated silage. Among the treatments, dry matter intake was the lowest in the silage treated with cassava meal. The organic matter, crude protein and NDF digestibility of the silage treated with molasses was higher than the silage without additive and the silage treated with FJLB. The rumen parameters: ruminal pH, ammonia-nitrogen ($NH_3$-N), volatile fatty acid (VFA), blood urea nitrogen (BUN) and bacterial populations were not significantly different among the treatments. In conclusion, these studies confirmed that the applying of molasses improved fermentative quality, feed intake and digestibility of Napier grass.

• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.648-660
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• 2014

Doenjang, a traditional Korean fermented soybean paste, is made by mixing and ripening meju with high salt brine (approximately 18%). Meju is a naturally fermented soybean block prepared by soaking, steaming, and molding soybean. To understand living bacterial community migration and the roles of bacteria in the manufacturing process of doenjang, the diversity of culturable bacteria in meju and doenjang was examined using media supplemented with NaCl, and some physiological activities of predominant isolates were determined. Bacilli were the major bacteria involved throughout the entire manufacturing process from meju to doenjang; some of these bacteria might be present as spores during the doenjang ripening process. Bacillus siamensis was the most populous species of the genus, and Bacillus licheniformis exhibited sufficient salt tolerance to maintain its growth during doenjang ripening. Enterococcus faecalis and Enterococcus faecium, the major lactic acid bacteria (LAB) identified in this study, did not continue to grow under high NaCl conditions in doenjang. Enterococci and certain species of coagulase-negative staphylococci (CNS) were the predominant acid-producing bacteria in meju fermentation, whereas Tetragenococcus halophilus and CNS were the major acid-producing bacteria in doenjang fermentation. We conclude that bacilli, LAB, and CNS may be the major bacterial groups involved in meju fermentation and that these bacterial communities undergo a shift toward salt-tolerant bacilli, CNS, and T. halophilus during the doenjang fermentation process.

• KSBB Journal
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• v.11 no.2
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• pp.125-131
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• 1996

In this study, Bucillus amyloliquefaciens was adopted as bacterial source to investigate the concentration of carbon source by adding inhibitors in the batch culture. By adding acetic acid at $10g/\ell$ of initial glucose concentration, maximum dry cell density was obtained with the highest value of /$\3.9gell$ at $1.0g/\ell$ of initial acetic acid concentration. By adding acetic acid al 10g/$\ell$ of initial glucose concentration, maximum ${\alpha}$-amylase production was obtained with 331.55unit/m1 at $2.0g/\ell$ of initial acetic acid concentration. ${\alpha}$-Amylase production was decreased with the increase of initial acetic acrid concentration. By adding acetic acid to the medium, cell growth and ${\alpha}$-amylase production was higher in glucose than in maltose. By adding lactic acid to the medium, cell growth was decreased.