Multi-sugar fermentation of lignocellulosic hydrolysate under industrially relevant conditions: comparison of several yeast strains

Both hexose- and pentose-fermenting yeasts are commercially available. The aim of this study was to test several yeast strains for their ability to ferment lignocellulosic feedstock and to evaluate their usability in a bioethanol production process based on the Cellunolix(R) concept. The Cellunolix(R) bioethanol demonstration plant of St1 uses sawdust to produce second-generation lignocellulosic ethanol. The study was performed in collaboration with yeast providers using two types of pretreated and filtered lignocellulosic ethanol hydrolysate originating from pine and willow. Ten pentose- and three hexose-fermenting yeast strains were tested. They all performed well under industrial conditions but differed in the rate of detoxification and profile for utilization of different sugars. A satisfactory 82-97% fermentation yield of a multi-sugar hydrolysate containing glucose, mannose, galactose, arabinose and xylose was achieved within 48 h. The results indicate significant potential for the usability of pentose-fermenting strains with real industrial hydrolysates and settings.