• 한국식품저장유통학회지
• /
• 제30권1호
• /
• pp.52-64
• /
• 2023

100 different yeast colonies were isolated from spontaneously fermented kiwis, persimmons, apples, pears, watermelons, grapes, grape fruits, peachs, and plums, and selected yeast strains were used to produce kiwi-persimmon mixed wine (KPMW). Among the isolates, five representative strains exhibited tolerance to sucrose, alcohol, pH, and potassium metabisulfite when compared with the control yeast strain (Saccharomyces cerevisiae KCCM 12615). All five yeast strains (Y4, Y10, Y28, Y78, and Y81) exhibited 99% 26S rDNA sequence similarity to S. cerevisiae. The pH, acidity, Brix, reducing sugar, alcohol, and organic acid contents were consistent in KPMW prepared from the S. cerevisiae KCCM 12615 and Y28 strains. KPMW made from the Y4, Y10, and Y28 strains exhibited lower quantities of free sugars than those of the KPMW made from the other yeast strains. The level of ethyl esters in KPMW prepared from the Y28 was higher than that in the other KPMWs. All strains, except for Y28, produced lower concentrations of sulfur and ketone compounds. Furthermore, the KPMW produced by the Y28 strains had total phenolic contents with 1.1 g/L, with DPPH and ABTS radical scavenging activities of 57.06% and 55.62%, respectively, and a FRAP assay value of 0.72. Our results suggest that Y28 is a promising yeast strain for producing high-quality wines.

• 미생물학회지
• /
• 제26권1호
• /
• pp.32-36
• /
• 1988

The yeast gene HOM3 encodes aspartokinase, which catalyses the first step (aspartate to and from beta-aspartyl phosphate) of common pathway to threonine and methionine. The yeast HOM3 gene expression is known to be regulated by threonine and methionine specific control, and also by general control of amino acid biosynthesis. Isolation and characterization of the HOM3 gene are essential for the molecular genetic study on its regulation of expression. A recombinant plasmid pSC3 (15.5kb, vector YCp50) has been cloned into E. coli HB101 from yeast genomic library through their complementing activity of HOM3 mutation in a yeast recipient strain M34-24B. Organization of the plasmid was characterized by delineation of restriction cleavage sites in the insert fragment.

• 한국미생물·생명공학회지
• /
• 제9권2호
• /
• pp.51-57
• /
• 1981

토양과 sludge 에서 1,2-propanediol을 자화할 수 있는 미생물을 분리하여 이들 중 가장 많은 젖산을 생성 하는 호모 한 균주(Y-1-4)를 선정하였다. 배양액에 생성된 산은 paper chromatography와 IR spectrum에 의해서 젖산으로 확인되었다. 이 효모는 탄소원으로서 ethanol, glycerin, glucose 및 1,2-propanediol 등을 자화할 수 있었는데 1,2-propanediol 으로부터만 젖산을 생성했다. 1,2-propanediol 에서부터 젖산생성의 최적 배지 및 최적 배양조건을 검토해서 1,2-propanediol 2.0%, NH$_4$Cl 0.5%, KH$_2$PO$_4$ 0.1%, MgSO$_4$.7$H_2O$ 0.05%, FeSO$_4$.7$H_2O$ 0.025%, yeast extract 0.04%와 CaCO$_3$ 0.3%를 함유하는 배지를 3$0^{\circ}C$에서 4일간 진탕 배양한 결과 젖산 생성량은 liter당 12.1gram 이었다.

• 한국미생물·생명공학회지
• /
• 제22권2호
• /
• pp.164-168
• /
• 1994

Identification of the Actinomycetes isolate strain No. 1372, a producer of Actinomycin X$_{2}$ was performed by using ISP method.l The strain, designated as No. 1372, was identified as Streptomyces floridae based on its morphological, physiological and biochemical characteristics. The highest production of the antibiotics by the strain was achieved in a fermentation medium containing soluble starch, yeast extract, (NH$_{4}$)SO$_{4}$, K$_{2}$HPO$_{4}$, NaCl$_{2}$, CaCO$_{3}$, and trace element.

• Journal of Microbiology and Biotechnology
• /
• 제21권1호
• /
• pp.55-61
• /
• 2011

Forty yeast strains isolated from soils taken from different locations in Egypt were tested for their P-solubilizing activities on the basis of analyzing the clear zone around colonies growing on a tricalcium phosphate medium after incubation for 5 days at $25^{\circ}C$, denoted as the solubilization index (SI). Nine isolates that exhibited P-solubilization potential with an SI ranging from 1.19 to 2.76 were genetically characterized as five yeasts belonging to the genus Saccharomyces cerevisiae and four non-Saccharomyces, based on a PCR analysis of the ITS1-26S region amplied by SC1/SC2 species-specific primers. The highest P-solubilization efficiency was demonstrated by isolate PSY- 4, which was identified as Saccharomyces cerevisiae by a sequence analysis of the variable D1/D2 domain of the 26S rDNA. The effects of single and mixed inoculations with yeast PSY-4 and Bacillus polymyxa on the P-uptake and growth of corn were tested in a greenhouse experiment using different levels of a phosphorus chemical fertilizer (50, 100, and 200 kg/ha super phosphate 15.5% $P_2O_5$). The results showed that inoculating the corn with yeast PSY-4 or B. polymyxa caused significant increases in the shoot and root dry weights and P-uptake in the shoots and roots. The P-fertilization level also had a significant influence on the shoot and root dry weights and P-uptake in the shoots and roots when increasing the P-level from 50 up to 200 kg/ha. Dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 200 kg/ha gave higher values for the shoot and root dry weights and P-uptake in the shoots and roots, yet these increases were nonsignificant when compared with dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 100 kg/ha. The best increases were obtained from dual inoculation with yeast strain PSY-4 and B. polymyxa at a P-fertilization level of 100 kg/ha, which induced the following percentage increases in the shoot and root dry weights, and P-uptake in the shoots and roots; 16.22%, 46.92%, 10.09%, and 31.07%, respectively, when compared with the uninoculated control (fertilized with 100 kg/ha).

• 한국식품과학회지
• /
• 제13권1호
• /
• pp.43-52
• /
• 1981

복숭아 solid pack을 변패시키는 내열성 효모의 열저항성 및 최적살균조건을 구명하기 위하여 원료복숭아의 초기 효모오염도를 조사하고 61균주를 분리보관하였다. 이중 내열성이 가장 강한 효모 No.15 균주에 대한 환경요인별 내열성 및 최적살균조건 시험결과는 아래와 같다. 1. 펩톤수와 복숭아쥬스에서 열처리하였을 때 대수기의 생장이 활발한 세포가 90시간 진탕배양후 10일간 유지한 것보다 내열성이 약했다. 2. 열매체로 펩톤수를 사용하여 열처리한 것이 복숭아쥬스에서 열처리한 것보다 내열성이 강했다. 3. 열처리후 회복배지에 있어서 YM 한천보다 복숭아쥬스 한천에서 회복시킨 것이 약했다. 4. 열매체나 회복배지에서의 pH에 따른 내열성은 pH 4.0에서가 pH 3.5에서 보다 내열성이 강했다 5. 일정한 온도로 가열할 때 생잔곡선은 초기의 열에 민감한 부분과 다음의 열에 안정한 부분의 broken curve를 나타내어 D 값을 구할 수 없었다. 6. 복숭아쥬스(pH 3.5)에서 열처리하여 복숭아쥬스 한천(pH 3.5)에 회복시켰을 때의 TDT 곡선에서 직선을 얻었으며 z값은 $4.8^{\circ}C$이었다. 7. 선발된 내열성 효모의 균학적 특성을 검토한 결과 Torulopsis candida로 추정되었으며 복숭아 solid pack에서의 변패성도 확인하였다. 8. 실제 4 oz 복숭아 solid pack에서의 inoculated pack test 결과 최적살균치 P.U. 70/5는 168(Z값$5^{\circ}C$, 기준온도 $70^{\circ}C$, 살균시간 18분, 관내 중심 온도 $78.5^{\circ}C$)이었다.

• 미생물학회지
• /
• 제32권4호
• /
• pp.271-279
• /
• 1994

${\alpha}$-Amylase와 glucoamylase를 동시에 안정하게 분비하여 전분을 일단계로 직접 에탄올로 발효시킬수 있는 효모 균주를 개발하기 위하여 glucoamylase를 분비하는 Saccharomyces diastaticus hybrid 균주에 쥐의 침샘 유래의 ${\alpha}$-amylase cDNA 유전자를 plasmid vector를 이용하여 도입하였다. 이 균주로부터 효소생산에 필요한 유전자를 잃어버림이 없이 안정하게 분비할 수 있도록 하기 위하여 $\alpha$-amylase 유전자를 효모의 염색체에 삽입시키기 위한 integrating plasmid vector인 YIpMS$\Delta$R(LEU2)를 제작하였다. 이 vector의 효모형질전환에 있어 원형(circular)상태와 제한 효소 XbaI으로 처리된 직선화된(linearized) 상태의 두가지 형태를 비교한 결과 형질전환 효율에서나 형질전환체내의 $\alpha$-amylase 유전자 보유정도가 모두 직선화된 형태의 경우가 원형상태의 경우보다 높았다. Linearized vecotr를 가진 효모 형질전환체에서의 유전자 발현 안정도는 세포분열을 거듭할수록 episomal vecotr에 의한 효모 형질전환체에서의 발현 안정도보다 우수하게 나타났다. 또한 이 linearized vector를 가진 형질전환체는 $\alpha$-amylase와 glucoamylase를 동시에 분비하여 glucoamylase만 분비하는 원균주보다 2배 이상의 전분분해력을 보였다.

• Applied Biological Chemistry
• /
• 제16권2호
• /
• pp.85-93
• /
• 1973

탁주료의 발효(醱酵)에 미치는 효모(酵母)의 종류(種類)와 담금조건(條件)의 영향을 검토(檢討)하여 다음의 결과(結果)를 얻었다. 1. 효모(酵母)의 종류(種類)와 료중의 효모수(酵母數) (1) 일단료를 $20^{\circ}C$에서 $1.5{\sim}2.5$일간(日間) 발효(醱酵)시키거나 $25^{\circ}C$와 $30^{\circ}C$에서 $1{\sim}2$일간(日間) 발효(醱酵)시킨 경우 효모분포(酵母分布)에 있어서 탁주효모(濁酒酵母)인 strain $D_m-1$과 청주효모(淸酒酵母)인 strain No.7사이에 별(別)로 차(差)가 없었다. (2) 이단료를 고온(高溫)($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우에는 저온발효(低溫醱酵)의 경우에 비(比)하여 료중의 효모수(酵母數)가 감소(減少)되었으나 탁주효모(濁酒酵母)인 strain $D_m-1$의 료중의 생존효모수(生存酵母數)는 청주효모(淸酒酵母)인 strain. No.7의 것보다 훨씬 많았다. 2. 효모(酵母)의 종류(種類)와 숙성료의 성분(成分) (1) 이단료를 고온(高溫) ($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우 선정(選定)한 탁주효모(濁酒酵母)(strain $D_m-1$, strain Y-1)을 使用한 숙성료의 주도(酒度)는 타효모(他酵母)(strain No.7, strain No.6, strain No.396, 및 strain No.1)를 사용(使用)한 것보다 상당(相當)히 높았다. (2) 료의 산도(酸度)는 strain $D_m-1$과 strain No.7사이에 약간 차이(差異)가 있었다. (3) 이단료를 고온(高溫) ($30^{\circ}C$ 또는 $35^{\circ}C$)에서 발효(醱酵)시킨 경우 strain $D_m-1$을 사용(使用)한 료의 Formol-N는 strain No.7을 사용(使用)한것보다 상당(相當)히 적었다. 3. 담금조건(條件)과 료의 주도(酒度) (1) 밀기울국(麴)의 첨가량(添加量)은 원료(原料)에 대하여 3%가 적당(適當)하였으며 밀가루국(麴)과 혼용(混用)할때에는 밀가루국(麴) 20%, 밀기울국(麴)은 $1{\sim}2%$를 사용(使用)하는 것이 적당(適當)하였다. (2) 일단료의 담금농도(濃度)를 보통(普通)것의 2배(倍)로 희석(稀釋)하여도 효모(酵母)의 증식(增殖)에 이상(異常)이 없었다. (3) 담금용수(用水) 180ml에 대하여 밀가루 $80{\sim}140g$를 사용(使用)한 경우 원료(原料)밀가루량(量)의 증가(增加)에 따라 료의 주도(酒度)가 대략(大略) 비례적(比例的)으로 올랐다. (4) 현행(現行)의 이단식(二段式)담금법(法)보다 삼단식(三段式)담금법(法)이 유리(有利)하다고 인정(認定)되었다.

• Journal of Microbiology and Biotechnology
• /
• 제33권8호
• /
• pp.1023-1029
• /
• 2023

Biosurfactants reduce surface and interfacial tension due to their amphiphilic properties and are an eco-friendly alternative for chemical surfactants. In this study, a new yeast strain JAF-11 that produces a biosurfactant was selected using drop collapse method, and the properties of the extracts were investigated. The nucleotide sequences of the strain were compared with closely related strains and identified based on the D1/D2 domain of the large subunit ribosomal DNA (LSU) and internal transcribed spacer (ITS) regions. Neodothiora populina CPC 39399^T, the closest species with strain JAF-11, showed a sequence similarity of 97.75% for LSU and 94.27% for ITS, respectively. The result suggests that the strain JAF-11 represents a distinct species that cannot be assigned to any existing genus or species in the family Dothideaceae. Strain JAF-11 produced a biosurfactant reducing the surface tension of water from 72 mN/m to 34.5 mN/m on the sixth day of culture and the result of measuring the critical micelle concentration (CMC) by extracting the crude biosurfactant was found to be 24 mg/l. The molecular weight 502 of the purified biosurfactant was confirmed by measuring the fast atom bombardment mass spectrum. The chemical structure was analyzed by measuring ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and two-dimensional NMRs of the compound. The molecular formula was C₂₆H₄₆O₉, and it was composed of one octanoyl group and two hexanoyl groups to myo-inositol moiety. The new biosurfactant is the first report of a compound produced by a new yeast strain, JAF-11.

• Mycobiology
• /
• 제43권3호
• /
• pp.266-271
• /
• 2015

Several types of yeasts were isolated from wild flowers around Jangseong Lake in Jeollanam-do, Republic of Korea and identified by comparing the nucleotide sequences of the PCR amplicons for the D1/D2 variable domain of the 26S ribosomal DNA using Basic Local Alignment Search Tool (BLAST) analysis. In total, 60 strains from 18 species were isolated, and Pseudozyma spp. (27 strains), which included Pseudozyma rugulosa (7 strains) and Pseudozyma aphidis (6 strains), was dominant species. Among the 60 strains, Bullera coprosmaensis JS00600 represented a newly recorded yeast strain in Korea, and its microbiological characteristics were investigated. The yeast cell has an oval-shaped morphology measuring $1.4{\times}1.7{\mu}m$ in size. Bullera coprosmaensis JS00600 is an asporous yeast that exhibits no pseudomycelium formation. It grew well in vitamin-free medium as well as in yeast extract-malt extract broth and yeast extract-peptone-dextrose (YPD) broth, and it is halotolerant growing in 10% NaCl-containing YPD broth.