• Journal of Microbiology and Biotechnology
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• 제33권3호
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• pp.371-377
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• 2023

In this study, a pepA gene encoding glutamyl (aspartyl)-specific aminopeptidase (PepA; E.C. 3.4.11.7) was cloned from Tetragenococcus halophilus CY54. The translated PepA from T. halophilus CY54 showed very low similarities with PepAs from Lactobacillus and Lactococcus genera. The pepA from T. halophilus CY54 was overexpressed in E. coli BL21(DE3) using pET26b(+). The recombinant PepA was purified by using an Ni- NTA column. The size of the recombinant PepA was 39.13 kDa as determined by SDS-PAGE, while its optimum pH and temperature were pH 5.0 and 60℃, respectively. In addition, the PepA was completely inactivated by 1 mM EDTA, indicating its metallopeptidase nature. The Km and Vmax of the PepA were 0.98 ± 0.006 mM and 0.1 ± 0.002 mM/min, respectively, when Glu-pNA was used as the substrate. This is the first report on PepA from Tetragenococcus species.

• 한국축산식품학회지
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• 제44권2호
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• pp.390-407
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• 2024

Kuflu cheese, a popular variety of traditional Turkish mold-ripened cheeses, is characterized by its semi-hard texture and blue-green color. It is important to elucidate the microbiota of Kuflu cheese produced from raw milk to standardize and sustain its sensory properties. This study aimed to examine the bacteria, yeasts, and filamentous mold communities in Kuflu cheese using high-throughput amplicon sequencing based on 16S and ITS2 regions. Lactococcus, Streptococcus, and Staphylococcus were the most dominant bacterial genera while Bifidobacterium genus was found to be remarkably high in some Kuflu cheese samples. Penicillium genus dominated the filamentous mold biota while the yeasts with the highest relative abundances were detected as Debaryomyces, Pichia, and Candida. The genera Virgibacillus and Paraliobacillus, which were not previously reported for mold-ripened cheeses, were detected at high relative abundances in some Kuflu cheese samples. None of the genera that include important food pathogens like Salmonella, Campylobacter, Listeria were detected in the samples. This is the first experiment in which the microbiota of Kuflu cheeses were evaluated with a metagenomic approach. This study provided an opportunity to evaluate Kuflu cheese, which was previously examined for fungal composition, in terms of both pathogenic and beneficial bacteria.

• 한국응용과학기술학회지
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• 제40권6호
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• pp.1445-1453
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• 2023

In 2022, the domestic production performance of functional cosmetics in South Korea reached 4.6 trillion won, accounting for 33.85% of the total cosmetics production. The number of functional cosmetics reviewed increased by about 7.5% from the previous year, totaling 974 items. Especially with the increasing importance of the skin barrier function due to skin sensitivity caused by various environmental pollutants, domestic cosmetic companies are showing interest in the development of new ingredients and products related to this area. This study aims to analyze academic research trends related to in vitro experiments for the development of cosmetics improving the skin barrier, to provide practical information for the cosmetic industry. The findings are as follows: Academic research mainly focused on the efficacy of natural ingredients in improving the skin barrier, but there is a significant lack of quantitative accumulation of research. For the development of skin barrier-improving cosmetic ingredients, efficacy evaluation indicators were set, including hyaluronic acid production, expression of filaggrin gene, loricrin, formation of cornified envelope (CE), and expression of ceramide synthesis enzyme genes. Moreover, effective cosmetic ingredients for improving the skin barrier included lemongrass and perilla leaf extracts, flavonoids, Lactococcus lactis subsp. lactis, Exosomelike Nanovesicles derived from apple callus, Eleutherococcus sessiliflorus, Acanthopanax sessiliflorus, Eleutherococcus gracilistylus, Acer okamotoanum extracts, Aloe vera adventitious root extract, ethanol extract of Aruncus dioicus, and organic solvent fraction of Dracocephalum argunense.

• 한국축산식품학회지
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• 제35권2호
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• pp.189-196
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• 2015

The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 10⁹ CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

• 한국어병학회지
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• 제14권1호
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• pp.3-10
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• 2001

식물성 생약재의 항균력과 활성산소(superoxide anion, $O_2^-$)의 생산에 미치는 in vitro 효과를 조사하여 금후 in vivo 실험에 적용할 때, 어류 체내 자연 저항성 증진을 꾀할 수 있는 식물성 생약재를 발굴하기 위한 기초자료를 얻고자 하였다. 식물성 생약재는 고삼, 귀전우, 구절초, 박하, 방풍, 연교, 약쑥, 지유, 삼백초, 삼지구엽초, 상백피, 소회향, 편축, 팔각 등 14종류로 이들을 열수추출하여 실험에 사용하였다. 항균력 시험에는 어병세균 Listonella anguillarum(Vibrio anguillarum), Vibrio sp., Vibrio alginolyticus, Edwardsiella tarda, Streptococcus sp., Lactcoccus garvieae를 대상으로 disk법을 사용하였으며, 활성산소의 생산능은 넙치 신장 대식세포를 이용한 nitroblue tetrazolium(NBT) 반응으로써 조사하였다. 그 결과,약쑥이 다른 생약재에 비하여 시험에 사용된 어병 세균에 대한 항균활성이 월등히 뛰어났으며, 또한 넙치 대식세포의 활성산소 생산능을 크게 자극하는 효과가 있음을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.68-76
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• 2006

Despites many attempts to explore the microbial diversity in kimchi fermentation, the predominant flora remains controversial to date. In the present study, major lactic acid bacteria (LAB) were investigated in Chinese cabbage kimchi in the early phase of fermention. For the samples over pH 4.0, viable cell counts of Leuconostoc and Pediococcus were $10^6\;cfu/ml$ and below $10^2\;cfu/ml$, respectively, and 20 isolates out of 172 were subjected to a biochemical identification (API 50 CH kit) as well as molecular-typing methods including ITSPCR with a RsaI digestion and 16s rRNA gene sequence analysis for species confirmation. Seven isolates were nicely assigned to Lb. brevis, 6 to Leuconostoc spp. (2 mesenteroides, 2 citreum, I carnosum, I gasicomitatum), 4 to Weissella (3 kimchii/cibaria, 1 hanii) and 2 to other Lactobacillus spp. (1 farciminis, 1 plantarum). On the other hand, the biochemical identification data revealed 9 strains of Lb. brevis, 6 strains of Leuconostocs,2 strains of Lb. plantarum and 1 strain each of Lb. coprophilus and Lactococcus lactis. However, a single isolates, YSM 16, was not matched to the ITS-PCR database constructed in the present study. Two Lb. brevis strains by API 50 CH kit were reassigned to W kimchii/cibaria, Lb. coprophilus or W hanii, respectively, judging from the results by the above molecular typing approaches. As a whole, the identification data obtained by the biochemical test were different from those of ITS-PCR molecular method by about $63\%$ at genus-level and $42\%$ at species-level. The data by the ITS-PCR method conclusively suggest that predominant LAB species is probably heterolactic Lb. brevis, followed by W kimchii/cibaria, Leuc. mesenteroides, and Leuc. citreum, in contrast to the previous reports [3] that Leuc. mesenteroides is the only a predominant species in the early phase kimchi fermentation.

• 한국식품위생안전성학회지
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• 제22권4호
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• pp.294-299
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• 2007

서울시 가락동 수산물 도매시장에서 시판되는 건포류 164건에 대해 API strep kit를 사용하여 87주의 균주들을 분리하였고 이 가운데 28주에서 E. faecalis, and E. faecium가, 11주에서 Lactococcus lactis ssp. lactis가 분리되었다. 28주의 E. faecalis와 E. faecium에서는 내성을 나타내는 항생제들이 streptomycin(95.6%), kanamycin(84.5%), gentamycin(66.7%), cephaloxin(97.8%), ampicillin/sulbactam(88.9%), ticarcillin(66.7%), amikacin(97.8%), sulfonamides(97.8%), ceftriaxone(75.6%), nalidixic acid(100.0%), 그리고 cefoxitin(100.0%) 등이었고, 감수성을 나타내는 항생제들은 amoxicillin/clavulanic acid(97.8%), chloramphenicol(95.6%), solfamethoxazole/trimethoprim(97.8%), 그리고 tetracycline(71.1%)등으로 나타났다. 또한, 이 가운데 가장 많은 다제내성 형태로는 10 균주의 E. faecalis에서 나타난 $S-K-GM-CF-SAM-TIC-An-S_3-CRO-NA-FOX$에 대한 것이었다. 결국, 건포류에서 분리한 E. faecalis 균주에서 항생제 다제내성이 분포함으로 나타나 probiotics로 사용되고 있는 이러한 균에 대한 항생제 내성의 결과가 의의가 있다고 사료된다.

• 한국미생물·생명공학회지
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• 제29권1호
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• pp.1-11
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• 2001

Lactic acid bacteria (LAB) are widely used for various food fermentation. With the recent advances in modern biotechnology, a variety of bio-products with the high economic values have been produced using microorganisms. For molecular cloning and expression studies on the gene of interest, E. coli has been widely used mainly because vector systems are fully developed. Most plasmid vectors currently used for E, coli carry antibiotic-resistant markers. As it is generally believed that the antibiotic resistance markers are potentially transferred to other bacteria, application of the plasmid vectors carrying antibiotic resistance genes as selection markers should be avoided, especially for human consump-tion. By contrast, as LAB have some desirable traits such that the they are GRAS(generally recognized as safe), able to secrete gene products out of cell, and their low protease activities, they are regarded as an ideal organism for the genetic manipulation, including cloning and expression of homologous and heterologous genes. However, the vec-tor systems established for LAB are stil insufficient to over-produce gene products, stably, limiting the use of these organisms for industrial applications. For a past decade, the two popular plasmid vectors, pAM$\beta$1 of Streptococcus faecalis and pGK12 theB. subtilis-E. coli shuttle vector derived from pWV01 of Lactococcus lactis ssp. cremoris wg 2, were most widely used to construct efficient chimeric vectors to be stably maintained in many industrial strains of LAB. Currently, non-antibiotic markers such as nisin resistance($Nis^{r}$ ) are explored for selecting recombi-nant clone. In addition, a gene encoding S-layer protein, slp/A, on bacterial cell wall was successfully recombined with the proper LAB vectors LAB vectors for excretion of the heterologous gene product from LAB Many food-grade host vec-tor systems were successfully developed, which allowed stable integration of multiple plasmid copies in the vec-mosome of LAB. More recently, an integration vector system based on the site-specific integration apparatus of temperate lactococcal bacteriophage, containing the integrase gene(int) and phage attachment site(attP), was pub-lished. In conclusion, when various vector system, which are maintain stably and expressed strongly in LAB, are developed, lost of such food products as enzymes, pharmaceuticals, bioactive food ingredients for human consump-tion would be produced at a full scale in LAB.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1123-1132
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• 2015

Winter wheat is a suitable crop to be ensiled for animal feed and China has the largest planting area of this crop in the world. During the ensiling process, lactic acid bacteria (LAB) play the most important role in the fermentation. We investigated the natural population of LAB in whole-crop wheat (WCW) and examined the quality of whole-crop wheat silage (WCWS) with and without LAB inoculants. Two Lactobacillus plantarum subsp. plantarum strains, Zhengzhou University 1 (ZZU 1) selected from corn and forage and grass 1 (FG 1) from a commercial inoculant, were used as additives. The silages inoculated with LAB strains (ZZU 1 and FG 1) were better preserved than the control, with lower pH values (3.5 and 3.6, respectively) (p<0.05) and higher contents of lactic acid (37.5 and 34.0 g/kg of fresh matter (FM), respectively) (p<0.05) than the control. Sixty LAB strains were isolated from fresh material and WCWS without any LAB inoculation. These LAB strains were divided into the following four genera and six species based on their phenotypic, biochemical and phylogenetic characteristics: Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, Lactococcus lactis subsp. lactis, Lactobacillus buchneri, and Lactobacillus plantarum subsp. plantarum. However, the prevalent LAB, which was predominantly heterofermentative (66.7%), consisted of Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, and Lactobacillus buchneri. This study revealed that most of isolated LAB strains from control WCWS were heterofermentative and could not grow well at low pH condition; the selective inoculants of Lactobacillus strains, especially ZZU 1, could improve WCWS quality significantly.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.500-506
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• 2017

To investigate the potential applications of bacterial heme, aminolevulinic acid synthase (HemA) was expressed in a Corynebacterium glutamicum HA strain that had been adaptively evolved against oxidative stress. The red pigment from the constructed strain was extracted and it exhibited the typical heme absorbance at 408 nm from the spectrum. To investigate the potential of this strain as an iron additive for swine, a prototype feed additive was manufactured in pilot scale by culturing the strain in a 5 ton fermenter followed by spray-drying the biomass with flour as an excipient (biomass: flour = 1:10 (w/w)). The 10% prototype additive along with regular feed was supplied to a pig, resulting in a 1.1 kg greater increase in weight gain with no diarrhea in 3 weeks as compared with that in a control pig that was fed an additive containing only flour. To verify if C. glutamicum-synthesized heme is a potential electron carrier, lactic acid bacteria were cultured under aerobic conditions with the extracted heme. The biomasses of the aerobically grown Lactococcus lactis, Lactobacillus rhamosus, and Lactobacillus casei were 97%, 15%, and 4% greater, respectively, than those under fermentative growth conditions. As a potential preservative, cultures of the four strains of lactic acid bacteria were stored at $4^{\circ}C$ with the extracted heme and living lactic acid bacterial cells were counted. There were more L. lactis and L. plantarum live cells when stored with heme, whereas L. rhamosus and L. casei showed no significant differences in live-cell numbers. The potential uses of the heme from C. glutamicum are further discussed.