• Geomechanics and Engineering
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• v.17 no.5
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• pp.485-496
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• 2019

Sealing of leakage in waterfront or water-retaining structures is one of the major issues in geotechnical engineering practices. With demands for biological methods as sustainable ground improvement techniques, bioclogging, defined as the reduction in hydraulic conductivity of soils caused by microbial activities, has been considered as an alternative to the chemical grout techniques for its economic advantages and eco-friendliness of microbial by-products. This study investigated the feasibility of bioaugmentation and biostimulation methods to induce fermentation-based bioclogging effect in coarse sands. In the bioaugmentation experiments, effects of various parameters and conditions, including grain size, pH, and biogenic gas generation, on hydraulic conductivity reduction were examined through a series of column experiments while Leuconostoc mesenteroides, which produce an insoluble biopolymer called dextran, was used as the model bacteria. The column test results demonstrate that the accumulation of bacterial biopolymer can readily reduce the hydraulic conductivity by three-to-four orders of magnitudes or by 99.9-99.99% in well-controlled environments. In the biostimulation experiments, two inoculums of indigenous soil bacteria sampled from waterfront embankments were prepared and their bioclogging efficiency was examined. With one inoculum containing species capable of fermentation and biopolymer production, the hydraulic conductivity reduction by two orders of magnitude was achieved, however, no clogging was found with the other inoculum. This implies that presence of indigenous species capable of biopolymer production and their population, if any, play a key role in causing bioclogging, because of competition with other indigenous bacteria. The presented results provide fundamental insights into the bacterial biopolymer formation mechanism, its effect on soil permeability, and potential of engineering bacterial clogging in subsurface.

• The Korean Journal of Food And Nutrition
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• v.35 no.6
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• pp.399-410
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• 2022

To enhance the bioavailability and bioactivities of mixed herbal medicines (RW), they were fermented with lactic-acid bacteria isolated from kimchi into postbiotics (FRW). Then, from the results of the 16s rRNA sequencing analysis, lactic acid bacteria isolated from kimchi were identified to be of two species, namely Lactobacillus sakei and Leuconostoc mesenteroides. The FRW prepared from the RW were extracted using hot water (HW) and 70% EtOH (EtOH) for comparison of their macrophage-stimulating activities. Based on a comparison of the activities of the FRW extracts, nitric oxide (NO) production of HW was significantly higher than that in EtOH. An analysis of the chemical properties of the extracts showed that HW had higher contents of neutral sugar and uronic acid than EtOH as well as contained a large amount of glucose. In addition, crude polysaccharide (CP) was prepared to enhance the macrophage-stimulating activity. The FRW-CP not only secreted immunostimulatory mediators but also increased the expression of immunostimulatory genes (iNOS, TNF-α, MCP-1, and IL-6). The fractionated FRW-CP contained about 90% neutral sugars, and these sugars were mainly composed of glucose, galacturonic acid, and arabinose. Thus, FRW prepared by fermentation of RW with kimchi lactic acid bacteria were found to be immunostimulatory modulators.

• The Korea Journal of Herbology
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• v.32 no.2
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• pp.65-75
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• 2017

Objectives : This study aimed to evaluate the protective effect of Orostachydis Herba (OH) and Fermented OH (OHF) against the acute liver injury by lipopolysaccharide (LPS). Methods : OHF by 4 lactic bacteria such as (Lactobacillus hilgardii (OHF1), Leuconostoc mesenteroides (OHF2), Pediococcus acidilactici (OHF3), Saccharomyces cerevisiae (OHF4)) were prepared. Samples were selected to OHF0, OHF2, OHF3 based on UPLC analysis, DPPH, ABTS radical scavenging activities. To evaluate the protective effect of OHF on liver injury mice, ICR mice were divided into 5 groups: Normal mice (Nor), LPS (20 mg/kg) treated mice (Veh), administrated OHF0, OHF2 OHF3 200 mg/kg body weight during 8 days before LPS injection. Serum and liver were collected 24 hours after LPS injection. Results : The activity was high in order of OHF0 and OHF3 in DPPH and ABTS radical scavenging activities. The quercetin contents for bioactive ingredient of OH was 5.39, kaempferol contents was 9.94 by UPLC analysis. The LPS-treated vehicle group significantly increased liver weight, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in serum. In contrast, administrated OHF3 group decreased liver weight, AST, ALT. In addition, OHF3 groups reduced the elevated levels of reactive oxygen species (ROS) in serum and tissues. Moreover, AP-1, iNOS and COX-2 were significantly decreased in OHF2 and OHF3. But $NF-{\kappa}B$ p65 and $TNF-{\alpha}$ only showed a significant reduction in OHF3. Conclusions : Therefore, these results suggest that fermented Orostachydis Herba might be protective effect on liver injury through anti-oxidant effect.

• The Korean Journal of Food And Nutrition
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• v.37 no.1
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• pp.17-29
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• 2024

To increase industrial applicability of Astragalus membranaceus (AM) as immunostimulating materials, hot-water extract (AME) was prepared from AM and fermented with Kimchi-lactic acid bacteria (Lactobacillus sakei & Leuconostoc mesenteroides) to prepare fermented AM-postbiotics (FAME). Although FAME prepared from AM-postbiotics did not show a significant enhancement in macrophage stimulating activity compared to non-fermented AME, crude polysaccharide (FAME-CP) fractionated by EtOH precipitation from FAME showed significantly higher macrophage stimulating activity than AME-CP. Compared to AME-CP, FAME-CP showed dramatic changes in component sugar and molecular weight distribution. FAME-CP was a polysaccharide with a major molecular weight distribution of 113.4 kDa containing Man (44.2%), Glc (19.3%), Gal (10.2%), GalA (10.2%), and Ara (7.4%) as sugar components. FAME-CP with enhanced macrophage stimulatory activity not only increased expression levels of mRNA genes encoding macrophage-activated factors (iNOS, TNF-α, MCP-1, IL-6, and COX-2), but also led the nuclear translocation of activated p65 and c-Jun. In conclusion, crude polysaccharide from AM-postbiotics fermented with lactic acid bacteria could increase industrial applicability as a functional material with enhanced immunostimulating activity than AME-CP.

• Journal of Microbiology and Biotechnology
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• v.34 no.4
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• pp.838-845
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• 2024

Excessive alcohol consumption can have serious negative consequences on health, including addiction, liver damage, and other long-term effects. The causes of hangovers include dehydration, alcohol and alcohol metabolite toxicity, and nutrient deficiency due to absorption disorders. Additionally, alcohol consumption can slow reaction times, making it more difficult to rapidly respond to situations that require quick thinking. Exposure to a large amount of ethanol can also negatively affect a person's righting reflex and balance. In this study, we evaluated the potential of lactic acid bacteria (LAB) to alleviate alcohol-induced effects and behavioral responses. Two LAB strains isolated from kimchi, Levilactobacillus brevis WiKim0168 and Leuconostoc mesenteroides WiKim0172, were selected for their ethanol tolerance and potential to alleviate hangover symptoms. Enzyme activity assays for alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) were then conducted to evaluate the role of these bacteria in alcohol metabolism. Through in vitro and in vivo studies, these strains were assessed for their ability to reduce blood alcohol concentrations and protect against alcohol-induced liver damage. The results indicated that these LAB strains possess significant ethanol tolerance and elevate ADH and ALDH activities. LAB administration remarkably reduced blood alcohol levels in rats after excessive alcohol consumption. Moreover, the LAB strains showed hepatoprotective effects and enhanced behavioral outcomes, highlighting their potential as probiotics for counteracting the adverse effects of alcohol consumption. These findings support the development of functional foods incorporating LAB strains that can mediate behavioral improvements following alcohol intake.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.2
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• pp.106-111
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• 2018

The main objective of this study was to determine the quality of rice straw silage made with various lactic acid bacteria (LAB) during fermentation. Five strains of LAB (Lactobacillus plantarum CMRT, L. leuconostoc mesenteroides M17, L. sakei C11, M5, SP2) were used in this study. With regard to odor, ready-made CMRT (a comparison strain) had the highest value from 10-60 days, followed by M17. The pH level of all silages made with five strains (apart from CMRT) ranged from 4.02 to 4.59. Of these, M17 rapidly lowered the pH value in the silage. Crude protein (CP) content was significantly lower (p < 0.01) in ready-made CMRT compared to the other bacteria. C11 fermentation produced the highest content of silage, with a score of 5.56. Acetic acid and butyric acid were not detected in any of the silage products. The lactic acid levels in silages produced by M17, M5, C11, and SP2 were comparatively higher than that produced by CMRT. The total digestible nutrient (TDN) content levels and relative fees value (RFV) were he highest in the silage of C11 (69.65 and 155.56, respectively), followed by M17. Based on odorl, pH, protein, organic acid, and feed value, we suggest tha the M17 strain is a suitable substitute for CMRT that can be used to generate high quality rice straw silage.

• Applied Biological Chemistry
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• v.14 no.2
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• pp.137-148
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• 1971

Studies were carried out to investigate the main fermentation microorganisms and their flora changes during Korean native soy-sauce fermentation. Korean native Maeju loaves collected from 5 Do's were separated into surface and inner parts. Four different soy-sauces-the surface part Maeju fermented soy-sauce, the inner part, the surface and inner part combined Maeju fermented soy-sauce, and the semi-Japanese type soy-sauce were fermented and the changes of fermentation microorganism flora and the various chemical components during the period of their fermentations were studied. Besides, 14 home-made soy-sauces collected from 14 different places all over Korea were examined in comparison with the laboratory soy-sauces and to determine the characteristics of Korean native soy-sauce. The results were as follows: 1. The main microorganisms in Korean native soy-sauce fermentation were determined as; Aerobic bacteria: Bacillus subtilis, Bacillus pumilus Lactic acid bacteria: Pediococcus halophilus, Leuconostoc mesenteroides Yeasts: Torulopsis datila, Saccharomyces rouxii 2. Microflora changes during Korean native soy-sauce fermentation were as follows; Aerobic bacteria increased until the 2nd week of fermentation and then gradually decreased. The lactic acid bacteria increased until the 3rd week, after which decreased. When the lactic acid fermentation lowered the pH value to below the 5.4, yeasts were able to grow and participate the fermentation. As the production of organic acids amounted, to a certain height, the growth of all microorganisms lead to the period of decline or death at about the 2nd month of fermentation. After boiling of soy-sauce most microorganisms except a few of Bacillus sp. disappeared. Occosionally yeasts and lactic acid bacteria survived depending upon the composition of soy-sauce. 3. Changes of general chemical components influencing the microflora were investigated for the period of Korean native soy-sauce fermentation. Tetal acidity, salt concentration and total nitrogen were increasing steadily over the entire period of fermentation. pH values were dropping to a certain degree of about 4.5. Salt concentration and pH value seemed to be the important factors influencing the microflora. 4. The microflora were influenced by chemical components of soy-sauce. Aerobic bacteria were able to survive in all soy-sauce as they made spores. Growth of lactic acid bacteria was inhited at 23-26% of salt concentration and pH 4.8. Soy-sauce yeasts started to grow only at pH below 5.4 and seemed to be inhibited at around 26% of salt concentration under pH 4.5-4.7. 5. The open kettle boiling of soy-sauce, the characteristic process of Korean native soy-sauce manufacturing, was effective to sterilize microorganisms, increase the salt concentration, and coagulate proteins. 6. The average viable cell counts of microorganism found in collected samples of home-made Korean native soy-sauces were; Aerobic bacteria: $53{\times}10^2\;cell/ml$ Lactic acid bacteria: 34 cell/ml Yeasts: 14 cell/ml The average values of chemical compositions of samples of home-made Korean native soy-sauce were; Salt concentration: 28.9% pH value: 4.79 Total acidity(lactic acid): 0.91g/100ml Total nitrogen: 1.09g/100ml

• The Korean Journal of Food And Nutrition
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• v.28 no.1
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• pp.16-23
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• 2015

This study was carried out to develop a fermented juice using persimmon (Diospyros kaki Thunb) and lactic acid bacteria isolated from kimchi, Lactobacillus buchneri BK-1, Pediococcus inopinatus BK-3 and Leuconostoc mesenteroides M-17. The total acidity value was 0.75% and viable cell number reached $1.9{\times}10^8CFU/mL$ when the persimmon and water solution was diluted by 1:3 (w/v) added with rice-syrup ($15^{\circ}Brix$) that was fermented by Lactobacillus buchneri BK-1 for 7 days. Additional levels of rice-syrup increased the total acidity of fermented juice, and the overall acceptability was the highest (4.1 point) for fermented persimmon juice added with rice-syrup $10^{\circ}Brix$. L. buchneri BK-1 and Pediococcus inopinatus BK-3 were selected to ferment the persimmon juice because there total acidity values were 0.83% and 0.80%, respectively, and the final cell concentrations, $5.1{\times}10^8$ and $2.7{\times}10^8CFU/mL$, were more than other treatment, respectively. The total acidity value of persimmon at day 3 of fermented broth were significantly higher than that of day 7 of fermented broth, and the number of viable cell declined from $8.2{\times}10^8$ to $4.3{\times}10^8CFU/mL$. In these results, the suitable period for fermentation was 4~5 days owing to the sourness being strong during fermentation.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.730-735
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• 1996

Antibacterial action of garlic extract against Escherichia coli was investigated. When the survival of E. cloi in tryptic soy broth (TSB) containing 50% garlic extract was compared with those of Lactobacillus plantarum, Leuconostoc mesenteroides and Staphylococcus aureus, E. coli was the most sensitive to garlic antibacterial action. When E. coli was inoculated into TSB with different concentrations of garlic extract, viable cell number decreased continuously during the test period even at 1% garlic extract. When E. coli was inoculated into pH-adjusted TSB containing 0.5% garlic extract, viable cell number of E. coli decreased continuously at initial pH of 5.2 and 6.2, while it decreased initially but increased to $8.0{\times}10^{7}\;CFU/ml at 48 hr at pH 7.2. With larger initial populations $(10^{6}\;CFU/ml), E. coli grew without apparent inhibition, while with smaller initial populations $(<10^{5}\;CFU/ml), viable cell number decreased initially but later increased. Thiol compounds like cysteine and glutathione, with free SH group (s), helped E. coli to grow or survive better in TSB with inhibitory level (5%) of garlic extract. The possibility of eliminating E. coli by using garlic extract from foods like kimchi of which garlic is one of regular ingredients is suggested.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.262-268
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• 2003

Kefir is a traditional fermented milk in Caucasusian area and is made mainly of milk fermented with lactic acid bacteria and yeasts. Six typical kefir grains were selected from ten kefir grains collected from different locals in Korea. Kefir grains were gelatinous in texture and had various shapes of villi, grapes, leaves, hulled millets, and towels. To investigate predominant microflora of kefir grains, SPC, MRS, M17, Rogosa, and APT agar media were used for viable cell count MRS, SPC, and Rogosa media were most acceptable for bacterial cell counts of the selected kefir grains. From one or two of the SPC agar plates which contained around 25∼50 colonies, all grown colonies were isolated and identified. Most predominant bacteria was identified as Lactobacillus fermentum by API 50 CHL kit. The proportions of Lb. fermentum and Lb. brevis among the total identified bacteria were around 41~88% and M4%, respectively. To select the best preservation method for kefir grains, refrigeration, freezing, and freeze drying were compared. Freeze drying was found most suitable for the preservation of kefir grains, based upon their acid-producing activities and production of off-flavors.