• Applied Biological Chemistry
• /
• 제49권3호
• /
• pp.180-185
• /
• 2006

본 연구는 Debaryomyces sp.가 생산하는 ${\alpha}-galactosidase$의 mannobiose-sepharose 담체합성법에 의한 affinity column chromatography를 수행하여 효소정제, 효소 화학적 성질 및 galactosyl mannooligosacchrides에 대한 기질특이성 규명을 주요 목적으로 하였다. 배양시간별 활성과 pH의 변화에서 배양시간 40시간부터 활성이 증가하고 있으며, 70시간에서 25.8unit/ml의 최대활성을 나타내고 있으며, 배양초기 pH 6.0에서 시작되어 배양말기에는 pH 8을 나타내는 pH의 변화를 보였다. 최적 pH는 4.0, 최적온도는 $60^{\circ}C$이며 $pH\;3{\sim}4.5$에서 100%의 잔존활성을 나타낸 반면 pH 8.0에서는 20%로 급격히 감소하였고. 온도안정성에서 $30{\sim}50^{\circ}C$에서는 100%의 잔존활성을 나타내었으나 $70^{\circ}C$ 이상에서는 20% 이하의 잔존활성을 나타내었다. $Hg^{2+}$에 의해서 54%, $Ag^{2+}$에 의해서는 85%로 저해되었으며, 그 이외의 이온에 대해서는 큰 영향을 받지 않았다. Debaryomyces sp.유래 ${\alpha}-galactosidase$는 24시간 반응 후 melibiose, $Gal^3Man_3$를 완전 가수분해 하여 각각 galactose와 glucose, galactose와 mannotriose로 분해되었으나 $Gal^3Man_4$에 대해서는 12시간 반응시켜도 기질로부터 galactose 유리가 불가능함이 확인되었다.

• 한국미생물·생명공학회지
• /
• 제24권4호
• /
• pp.430-438
• /
• 1996

The eleven strains, which could be used lactic and acetic acids as carbon sources, were isolated from kimchi and identified; the strains were facultative microorganisms which could be grown at low temperature (10$\circ$C) and around pH 3.2. As results of morphological, biochemical and physiological tests, 5 species of 3 genera were identified as Debaryomyces coudertii, Pichia edia, Pichia chambardii, Pichia haplophilia and Saccharomyces fermentati. Each strain was grown in basal media. In acidic resistance and acid utilization test, Saccharomyces sp. YK- 17 and Saccharomyces fermentati YK-19 were grown well in basal and YM media containing 0.3% lactic acid. And two strains were grown in basal and YM media containing O.3% lactic acid and 0.6% acetic acid. Since strain YK-19 was grown better at 10$\circ$C than that in 25$\circ$C, strain YK-19 was known to be a psychrophilic strain.

• Journal of Microbiology and Biotechnology
• /
• 제28권1호
• /
• pp.105-108
• /
• 2018

Beef was dry aged for 40-60 days under controlled environmental conditions in a refrigerated room with a relative humidity of 75%-80% and air-flow. To date, there is little information on the microbial diversity and characteristics of dry aged beef. In this study, we explored the effect of change in meat microorganisms on dry aged beef. Initially, the total bacteria and LAB were significantly increased for 50 days during all dry aging periods. There was an absence of representative foodborne pathogens as well as coliforms. Interestingly, fungi including yeast and mold that possess specific features were observed during the dry aging period. The 5.8S rRNA sequencing results showed that potentially harmful yeasts/molds (Candida sp., Cladosporium sp., Rhodotorula sp.) were present at the initial point of dry aging and they disappeared with increasing dry aging time. Interestingly, Penicillium camemberti and Debaryomyces hansenii used for cheese manufacturing were observed with an increase in the dry aging period. Taken together, our results showed that the change in microorganisms exerts an influence on the quality and safety of dry aged beef, and our study identified that fungi may play an important role in the palatability and flavor development of dry aged beef.

• 한국미생물·생명공학회지
• /
• 제24권4호
• /
• pp.512-518
• /
• 1996

Eleven strains had been previously isolated from kimchi and identified in our laboratory. The ability of each strain in aroma production was investigated by sensory evaluation. Among them Saccharomyc s sp. YK-17, Saccharomyces sp. YK-18, Saccharomyces sp. YH-3 and Saccharomyces fermentati YK-19 produced fruity flavour. Especially, Saccharomyces fermentati YK-19 produced apple and pineapple-like flavours. Pichia media YK-11, Saccharomyces sp. YK-20 and Pichia chambardii YH-4 produced wine-like flavour. Debaryomyces sp. YK-6, Debarymyces coudertii YK-10, Saccharomyces sp. YK-12 and Pichia haplophilia YH-5 produced alcoholic flavours. Using the good flavour producing strains as starters, various groups of kimchi were fermented, and the sensory characteristics of each group such as odor, taste and total acceptability were evaluated. The acidic odor, moldy odor and taste were reduced by adding starter, while the fresh sourness odor and taste similar to fruity fiavour were increased by starter. Comparing with the control group, these odor, taste and total acceptability were increased in the starter-added groups, such as Pichia edia YK-11, Saccharomyces sp. YK-17, and Saccharomyces,fermentati YK- 19. Saccharomyces fermentati YK-19 added kimchi group was higher siginificantly (P<0.05) than the others at the total acceptability. Volatile compounds of the culture broth of Saccharomyces fermentati YK-19 were analysed by gas chromatography, and 6 species of esters and 4 species of alcohols were identified. Among them, the ester substances which broth largely responsible for the apple-like flavour in the sensory evaluation, were found to be ethyl 2-methyl butvrate, ethyl pentanoate and ethyl acetate.

• 미생물학회지
• /
• 제42권2호
• /
• pp.111-115
• /
• 2006

연안해역에서 분리된 해양효모 중 불포화 지방산을 함유한 두 종의 해양효모를 선정하여 물벼룩인 Moina macrocopna에 먹이로 투여하여 먹이의 유효성과 먹이의 선호도를 방사성 안전 동위원소를 사용하여 실험한 결과를 요약하면 다음과 같다. 1. 두 종의 해양효모 Debaryomyces sp. Y-14는 전체 지방산 중 Docosahexaenoic acid (DHA)가 3.6%이고 총 아미노산 함량이 34.9%이며, Candida sp. Y-16는 지방산중 Eicosa pentaenoic acid (EPA)가 0.4%이고 총 아미노산이 46.2%였다. 2. Debaryomyces sp. Y-14로 배양한 M. macrocopa는 전체 지방산 함량 중 DHA가 5.5%, 총 아미노산 함량이 49.2%이고, Candida sp. Y-16으로 배양한 M. macrocopa는 전체 지방산 함량 중 EPA가 2.1%, DHA가 0.6%이고 총 아미노산 함량은 30.3% 였다. 3. 탄소안정 동위원소(${\delta}^{13}C$)는 Debaromyces sp. Y-14는 $-11.5\%_{\circ}$이고 Candida sp. Y-16은 $-10.1\%_{\circ}$이고 대조구인 Erythrobacter sp. $S{\pi}-1$은 $-24.1\%_{\circ}$로 약 $14\%_{\circ}$정도의 차이를 보였다. 4. 해양효모를 M. macrocopa에 먹이로 투여했을 때 ${\delta}^{13}C$값은 $-10.9\%_{\circ}$, Erythrobacter sp. $S{\pi}-1$을 먹이로 투여한 경우는 $-21.8\%_{\circ}$였다. 5. M. macrocopa의 생체내 탄소의 회전율은 실험초기에는 $-15\%_{\circ}$와 $-13\%_{\circ}$였지만 Erythrobacter sp. $S{\pi}-1$으로 바꾸어 20일 정도 배양한 결과 $-19\%_{\circ}$로 안정화되는 경향이 있었다. 6. 먹이의 선호도는 배양 4일부터 M. macrocopa 생체내의 ${\delta}^{13}C$값이 $-13\%_{\circ}$에서 $-10\%_{\circ}$사이의 범위로 나타나 해양효모에 가까운 값으로 대조구인 Erythrobacter sp. $S{\pi}-1$보다 선호하는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
• /
• 제19권8호
• /
• pp.743-748
• /
• 2009

Fungal diversity during composting was investigated by culture-independent rDNA sequence analysis. Composting was carried out with pig manure and mushroom cultural waste using a field-scale composter (Hazaka system), and samples were collected at various stages. Based on partial sequence analysis of large subunit (LSU) ribosomal RNA (rRNA) and sequence identity values, a total of 12 different fungal species were found at six sampling sites; Geotrichum sp., Debaryomyces hansenii, Monographella nivalis, Acremonium strictum, Acremonium alternatum, Cladosporium sphaerospermum, Myriangium durosai, Pleurotus eryngii, Malassezia globosa, Malassezia restricta, Rhodotorula glutinis, and Fusarium sporotrichioides. Geotrichum sp. of the class Saccharomycetes was the most predominant fungal species throughout the composting process (185 out of a total of 236 identified clones, or 78.4%), followed by Acremonium strictum (7.6%), Monographella nivalis (5.1%), and Pleurotus eryngii (3.8%). The prevalence of Geotrichum sp. was the lowest (61.1%) at the beginning of composting, and then gradually increased to 92.5% after 10 days of composting.