Journal of Microbiology

Research Support, Non-U.S. Gov't

Degradation of Malic Acid by Issatchenkia orientalis KMBL 5774, an Acidophilic Yeast Strain Isolated from Korean Grape Wine Pomace: Sung-Hee Seo , Chang-Ho Rhee , Heui-Dong Park; J. Microbiol. 2007;45(6):521-527.; DOI: https://doi.org/2641 [pii]

Abstract: Several yeast strains degrading malic acid as a sole carbon and energy source were isolated from Korean wine pomace after enrichment culture in the presence of malic acid. Among them, the strain designated as KMBL 5774 showed the highest malic acid degrading ability. It was identified as Issatchenkia orientalis based on its morphological and physiological characteristics as well as the nucleotide sequences of the internal transcribed spacer (ITS) I-5.8S rDNA-ITS II region. Phylogenetic analysis of the ITS I-5.8S rDNAITS II sequences showed that the KMBL 5774 is the closest to I. orientalis zhuan 192. Identity of the sequences of the KMBL 5774 was 99.5% with those of I. orientalis zhuan 192. The optimal pH of the media for the growth and malic acid degradation by the yeast was between 2.0 and 3.0, suggesting that the strain is an acidophile. Under the optimized conditions, the yeast could degrade 95.5% of the malic acid after 24 h of incubation at 30°C in YNB media containing 2% malic acid as a sole carbon and energy source.

Growth of Issatchenkia orientalis in Aerobic Batch and Fed-batch Cultures: Hyung Tai Shin , Yoo Beom Lim , Jong Ho Koh , Jong Yun Kim , Soon Young Baig , Jae Heung Lee; J. Microbiol. 2002;40(1):82-85.

Abstract: The aerobic batch growth of Issatchenkia orientalis DY252 with glucose and fructose medium was investigated at 32 C and pH 5.0. Aerobic ethanol production was evident with yeast I. orientalis. A diauxic lag of about 1 h between growth on glucose and growth on ethanol during batch culture was observed. However, no diauxic growth occurred with fructose. As the incubation temperature was increased from 32 to 39 C, viability at the end of each batch culture declined significantly, from 93 to 43%. Unlike the effect of temperature, viability was not greatly affected by incubation pH, and cell yield values in a range of 0.45-0.48 were obtained. In order to overcome overflow metabolism, a fed-batch culture under glucose limitation was carried out. Compared with aerobic batch culture, about 10% improvement in cell yield was achieved with a fed-batch culture in optimal conditions.

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