Isolation, characterization, and fermentative pattern of a novel thermotolerant Prototheca zopfii var. hydrocarbonea strain producing ethanol and CO sub(2) from glucose at 40 degree C

• Published in: Archives of microbiology Vol. 177; no. 3; pp. 244 - 250
• Main Authors: Ueno, R, Urano, N, Suzuki, M, Kimura, S
• Format: Journal Article
• Language: English
• Published: 01-03-2002
• Subjects: Algae; Prototheca zopfii; Prototheca zopfii hydrocarbonea
• ISSN: 0302-8933
• DOI: 10.1007/s00203-001-0384-0

A novel thermotolerant strain of the achlorophyllous micro-algaPrototheca was isolated from a hot spring. The isolate was found to produce an appreciable amount of ethanol and CO sub(2) from glucose under anoxic conditions at both 25 and 40 degree C; this type of alcohol fermentation has not yet been reported in the genus Prototheca. Moreover, it also evolved gas from sucrose after a time lag at 40 degree C. Its taxonomic characteristics coincided with those of Prototheca zopfii var.hydrocarbonea, and phylogenetic analysis, based on a small-subunit (SSU) rDNA sequence, also revealed a close relationship between the two strains. D-lactic acid, ethanol, CO sub(2) and a trace of acetic acid were produced from glucose, butL-lactic acid, formic acid, and H sub(2) were not. At 25 degree C,D-lactic acid and ethanol were produced in approximately equimolar amounts under N sub(2)/H sub(2) /CO sub(2), whereas ethanol production was predominant under N sub(2). More ethanol was produced at 40 degree C than at 25 degree C irrespective of the gas composition in the atmosphere. This is the first report on gas production from glucose and on the changes in the fermentative patterns as a function of temperature for the genus Prototheca.