Comparing cell viability and ethanol fermentation of the thermotolerant yeast Kluyveromyces marxianus and Saccharomyces cerevisiae on steam-exploded biomass treated with laccase

Abstract

In this study, the thermotolerant yeast Kluyveromyces marxianus CECT 10875 was compared to Saccharomyces cerevisae Ethanol Red for lignocellulosic ethanol production. For it, whole slurry from steam-exploded wheat straw was used as raw material, and two process configurations, simultaneous saccharification and fermentation (SSF) and presaccharification and simultaneous saccharification and fermentation (PSSF), were evaluated. Compared to S. cerevisiae, which was able to produce ethanol in both process configurations, K. marxianus was practically inhibited, and neither growth nor ethanol production occurred during the processes. However, the prior laccase treatment of the whole slurry, which removed specifically the lignin phenols content from the overall inhibitory compounds present in slurry, triggered the fermentation by k. marxianus, attaining ethanol concentrations and yields comparable to those obtained by S. cerevisiae.