Ethanol reassimilation and ethanol tolerance in Pichia stipitis CBS 6054 as studied by 13C nuclear magnetic resonance spectroscopy

Abstract

Ethanol reassimilation in Pichia stipitis CBS 6054 was studied by using continuous cultures, and the oxidation of [1-13C]ethanol was monitored by in vivo and in vitro 13C nuclear magnetic resonance spectroscopy. Acetate was formed when ethanol was reassimilated. The ATP/ADP ratio and the carbon dioxide production decreased, whereas the malate dehydrogenase activity increased, in ethanol-reassimilating cells. The results are discussed in terms of the low ethanol tolerance in P. stipitis compared with that in Saccharomyces cerevisiae (S. W. Brown, S. G. Oliver, D. E. F. Harrison, and R. C. Righelato, Eur. J. Appl. Microbiol. Biotechnol. 11:151-155, 1981).