• Journal of Microbiology and Biotechnology
• /
• 제33권8호
• /
• pp.1066-1075
• /
• 2023

Kimchi is a traditional Korean fermented vegetable that is stored and fermented at low temperatures. However, kimchi lactic acid bacteria (LAB) are typically isolated under mesophilic conditions, which may be inappropriate for isolating the diverse LAB. Therefore, this study investigated the suitable conditions for isolating various LAB from kimchi. Here, LAB were isolated from four kimchi samples using MRS, PES, and LBS media and varying isolation temperatures (30, 20, 10, and 5℃). Then, MRS was selected as the suitable medium for LAB isolation. A comparison of culture-dependent and culture-independent approaches indicated that 5℃ was not a suitable isolation temperature. Thus, the number and diversity of LAB were determined at 30, 20, and 10℃ using 12 additional kimchi samples to elucidate the effect of isolation temperature. With the exception of two samples, most samples did not substantially differ in LAB number. However, Leuconostoc gelidum, Leuconostoc gasicomitatum, Leuconostoc inhae, Dellaglioa algida, Companilactobacillus kimchiensis, Leuconostoc miyukkimchii, Leuconostoc holzapfelii, and Leuconostoc carnosum were isolated only at 10 and 20℃. The growth curves of these isolates, except Leu. holzapfelii and Leu. carnosum, showed poor growth at 30℃. This confirmed their psychrotrophic characteristics. In Weissella koreensis, which was isolated at all isolation temperatures, there was a difference in the fatty acid composition of membranes between strains that could grow well at 30℃ and those that could not. These findings can contribute to the isolation of more diverse psychrotrophic strains that were not well isolated under mesophilic temperatures.

• Journal of Microbiology and Biotechnology
• /
• 제9권6호
• /
• pp.861-869
• /
• 1999

An extracellular protease was purified to homogeneity from the culture supernatant of psychrotrophic bacteria Bacillus sp. JH 108 using procedures including ammonium sulfate fractionation, anion exchange chromatography, gel filtration chromatography, and cation exchange chromatography. The enzyme exhibited a molecular weight of 36 kDa, an optimum pH of 8 to 9, and optimum temperature of $60^{\circ}C$. The enzyme preferentially hydrolyzed leucine at the N-terminus of peptides and thus can be classified as an aminopeptidase. It was strongly inhibited by metal chelating agents such as EDTA and l, l0-phenanthroline. The activity lost by EDTA was restored with $Zn^{2+}{\;}or{\;}Co^{2+}$. These divalent cations also stimulated the native enzyme. This suggests that the enzyme is a metalloprotease acting as a leucine aminopeptidase.

• 한국환경보건학회지
• /
• 제22권4호
• /
• pp.109-121
• /
• 1996

It was intended to investigate the effect of the microbiological kitchen hygiene such as dishclothes and scrubbers. The 8indicator organisms (standard plate counts, coliform, heterotroph, enterococcus, staphylococcus, heat-stable bacteria, psychrotroph, Pseudomonas aeruginosa) were detected highly in dishwaters, dishcloth and scrubber. Coliform and Staphylococcus aureus were appeared on dishcloth dominantly than the scrubber, and the scrubbers were intruded by hetrotrophs and psychrotrophs numerously than dishclothes. The germ-resistant sponge inhibited the growth of the most of test strain, and appeared the about 100% reduction rate after 24 hr, but did not affect Pseudomonas aeruginosa and P. fragi so typically after 24 hr. The anti-microorganism durability of germ-resistant sponge, treated with food soil, was maintained by 10 days, the early stage strain density was founded in 20 days, and the strains grew after 30 days.

• Journal of Microbiology and Biotechnology
• /
• 제14권5호
• /
• pp.952-958
• /
• 2004

Of 23 psychrotrophic bacteria isolated from the west Pacific deep-sea sediments, 19 were assigned to the $\gamma$-Proteobacteria, 3 to the <$\beta$-Proteobacteria, and 1 to the Gram-positive bacteria, as determined by their 16S rDNA sequences. Ten psychrotrophs, affiliated to the Psychrobacter, Pseudoalteromonas, and Pseudomonas genera in the $\gamma$-Proteobacteria group, were screened for lipolytic bacteria. The majority of the lipolytic isolates had growth temperatures between 4-$30^\circ{C}$, and all of them were neutrophilic, aerobic, or facultatively anaerobic, and some were able to produce multiple kinds of ectohydrolytic enzymes. The deep-sea strains Psychrobacter sp. wp37 and Pseudoalteromonas sp. wp27 were chosen for further lipase production analysis. Both strains had the highest lipase production when grown at 10 to $20^\circ{C}$; their highest lipase production occurred at the late-exponential growth stage; and the majority of the enzymes were excreted to the outside of the cells. Lipases from both strains had the same optimal reaction temperature and pH (20-$30^\circ{C}$, pH 7-8) and could retain about 60% of their highest activity at $4^\circ{C}$. Furthermore, SDS-PAGE and an in-gel activity test showed that they had the same high molecular mass of about 85 kDa.

• 한국식품영양학회지
• /
• 제7권4호
• /
• pp.392-398
• /
• 1994

The purpose of this study was to predict the actions and roles of 10 strains of representative psychrotrophic lactic acid bacteria, in kimchi fermentation, which were Isolated from kimchi and identified as Leu. mesenteroides subsp. mesenteroides, Leu. mesenteroides subsp. dextranicum, Leu. lactic, Leu. paramesenteroides, Lac. bavaricus and Lac. homahiochii. For this, 0.01% of tactic starters were inoculated in germ free Korean cabbage-juice containing 2.5% NaCl, and then cultivated for 14 days at 1$0^{\circ}C$. All strains grew actively, and reached their stationary phase in 4 days. In death phase, the slopes of curves were much different each other by strains. The acidity increased rapidly between 2 and 4 days, and the pH decreased rapidly between 2 and 3 days. The total acidity was 0.5B~0.75%, the volatile acidity 0.04~0.18% and the pH 3.55~3.85, in final cultures. The cultures of Leuconostocs were better than those of lactobacilli on flavor test. It was thought that the ripening periods of kimchi would be much reduced, and that the over ripening would be also somewhat avoided, when these strains were used as starter bacteria for kimchi and the kimchi was fermented at low temperature.

• 한국축산식품학회지
• /
• 제42권2호
• /
• pp.252-265
• /
• 2022

Kocuria salsicia can survive in extreme environments and cause infections, including catheter-related bacteremia, in humans. Here, we investigated and evaluated the characteristics of nine K. salsicia strains (KS1-KS9) isolated from cheese brine from a farmstead cheese-manufacturing plant in Korea from June to December, 2020. Staphylococcus aureus American Type Culture Collection (ATCC) 29213 was used as a positive control in the growth curve analysis and biofilm-formation assays. All K. salsicia isolates showed growth at 15% salt concentration and temperatures of 15℃, 25℃, 30℃, 37℃, and 42℃. KS6 and KS8 showed growth at 5℃, suggesting that they are potential psychrotrophs. In the biofilm-formation analysis via crystal violet staining, KS6 exhibited the highest biofilm-forming ability at various temperatures and media [phosphate buffered saline, nutrient broth (NB), and NB containing 15% sodium chloride]. At 25℃ and 30℃, KS3, KS6, and KS8 showed higher biofilm-forming ability than S. aureus ATCC 29213. The antimicrobial resistance of the isolates was evaluated using the VITEK^® 2 system; most isolates were resistant to marbofloxacin and nitrofurantoin (both 9/9, 100%), followed by enrofloxacin (7/9, 77.8%). Five of the nine isolates (5/9, 55.6%) showed multidrug resistance. Our study reports the abilities of K. salsicia to grow in the presence of high salt concentrations and at relatively low temperatures, along with its multidrug resistance and tendency to form biofilms.

• 한국식품과학회지
• /
• 제23권6호
• /
• pp.717-722
• /
• 1991

진공포장, 'rub', 저장온도와 첨가물에 따른 marinated 닭 drummettes의 품질변화를 조사했다. Drummettes의 초기 미생물 수에 따라 제품 품질수명은 영향을 받았다. 내부온도가 $93.3^{\circ}C$로 조리된 제품은 $82.2^{\circ}C$로 조리된 제품보다 품질수명이 길었다. 하지만 marinated 과정중 'rub'가 이용된 경우 위와 같은 장점은 나타나지 않았다. 냉장저장($3{\pm}1^{\circ}C$와$7{\pm}1^{\circ}C$)중 진공과 비진공 포장된 제품의 미생물 총균수는 현저한 차이가 없었다(P>0.05). Marinated 용액에 솔빈산(0.5%)이나 안식향산 나트륨(0.5%)을 첨가하여 제품 품질수명은 연장 되었으며 아질산 나트륨 50ppm을 첨가하여 좀더 연장 되었다. 진공포장과 marinated 용액에 솔빈산이나 안식향산 나트륨을 첨가하여 제품의 TBA값 증가를 둔화시켰다.

• 한국식품과학회지
• /
• 제35권6호
• /
• pp.1110-1116
• /
• 2003

신선 편의가공 양파제품의 적정 포장방법을 탐색하고자 polyolefin계 유연 필름(LDPE, PP)을 이용한 수동 MAP, 20% $O_2/10%\;CO_2/70%\;N_2$ 혼합기체 또는 에틸렌 흡수제를 첨가한 능동 MAP, LDPE 필름으로 감압 포장한 MVP 등의 적용 가능성을 조사하였다. 박피 양파의 포장방법을 달리하여 $10^{\circ}C$에서 28일간 저장하면서 이화학적, 미생물, 관능적 품질변화를 측정하여 개별 품질인자에 대한 포장처리 효과를 검토하였다. 전체적으로 포장방법에 따른 저장중 박피 양파의 표면색, 중량 감소, 미생물 증식은 차이를 분명하게 구분하기 어려웠으나, 외관품질과 부패율 측면에서는 일정한 차이를 식별할 수 있었다. 결과적으로 기체투과성 LDPE 필름에 일정수준의 진공을 적용하여 밀봉 포장한 MVP가 다른 포장구에 비해 상대적으로 박피 양파의 저장품질을 우수하게 유지하는 것으로 확인되었다.

• 한국식품과학회지
• /
• 제31권3호
• /
• pp.746-750
• /
• 1999

본 실험은 전자선조사가 돈육등심의 미생물학적 관능적 특성에 영향을 미치는 연구로써 돈육등심부위를 사용하여 호기적 조건하에서 폴리에틸렌 필름으로 포장하여 전자선 가속기를 이용(1 MeV) 총 흡수선량이 0.5, 1, 2 kGy가 되도록 하여 $4{\pm}1^{\circ}C$에서 저장하며 실험을 수행하였다. 전자선 조사선량의 증가가 총균수, 내냉성균수 그리고 젖산균수의 억제 효과를 보였다. 관능검사에 있어 삼점검사의 경우 전자선량의 증가하여도 처리구간의 식별강도가 낮게 나타났으며, 척도 묘사의 경우 신선육의 향기, 불쾌취, 육색 그리고 기호성에 별 영향이 없었으며, 조리육에 있어도 약간의 연도와 다즙성의 저하를 가져왔으나 향기, 풍미, 불쾌취, 기호성에 별영향을 미치지 않았다. 이상을 종합해 볼 때, 전자선에 대한 소비자들의 인식을 새롭게만 한다면 1 kGy 이하로 조사할 경우 위생적으로 저장기간을 연장시킬 수 있는 신선 돈육의 생산이 가능할 것으로 판단된다.

• 한국토양비료학회지
• /
• 제44권4호
• /
• pp.625-636
• /
• 2011

Cold-adapted bacteria survive in extremely cold temperature conditions and exhibit various mechanisms of adaptation to sustain their regular metabolic functions. These adaptations include several physiological and metabolic changes that assist growth in a myriad of ways. Successfully sensing of the drop in temperature in these bacteria is followed by responses which include changes in the outer cell membrane to changes in the central nucleoid of the cell. Their survival is facilitated through many ways such as synthesis of cryoprotectants, cold acclimation proteins, cold shock proteins, RNA degradosomes, Antifreeze proteins and ice nucleators. Agricultural productivity in cereals and legumes under low temperature is influenced by several cold adopted bacteria including Pseudomonas, Acinetobacter, Burkholderia, Exiguobacterium, Pantoea, Rahnella, Rhodococcus and Serratia. They use plant growth promotion mechanisms including production of IAA, HCN, and ACC deaminase, phosphate solublization and biocontrol against plant pathogens such as Alternaria, Fusarium, Sclerotium, Rhizoctonia and Pythium.