LAUSR

Higher alcohol isobutanol is a promising liquid fuel. During alcoholic fermentation, Saccharomyces cerevisiae produces only trace amounts of isobutanol. Screening our collection of non-conventional yeasts showed that Magnusiomyces magnusii accumulated 440 mg of isobutanol/L in YPD medium. Here, the transformation protocol for M. magnusii was adapted based on the use of the dominant markers conferring resistance to nourseothricin or zeocin; the strong constitutive promoter TEF1 was cloned and a reporter system based on LAC4 gene from Kluyveromyces lactis coding for β-galactosidase was constructed. In order to increase isobutanol production in M. magnusii, the heterologous gene ILV2 from S. cerevisiae was expressed in M. magnusii under control of the TEF1 promoter. The best stabilized transformants produced 620 mg of isobutanol/L in YPD medium and 760 mg/L in the medium with 2-oxoisovalerate. This suggests that M. magnusii is a promising organism for further development of a robust isobutanol producer. This article is protected by copyright. All rights reserved.