COMPARISON OF INDUSTRIAL YEAST STRAINS FOR FERMENTATION OF SPENT SULFITE PULPING LIQUOR FORTIFIED WITH WOOD HYDROLYSATE

Ethanol production from spent sulphite pulping liquor (SSL) was compar ed for four different yeasts, A second strain of S. cerevisiae as well as a 2-deoxyglucose-resistant strain formed through protoplast fusion s between S. uvarum and S. diastaticus produced up to 27% more ethanol from SSL fortified with hydrolysis sugars than was produced by S. cer evisiae, The incremental improvement in ethanol yield appeared to vary with the degree of fortification, ranging from 5.8% for unfortified S SL, to 27% for the highest level of fortification tested, Decreasing f ermentation rates were observed for SSL fortified with glucose, mannos e and galactose, respectively, Sugar uptake rates in SSL fortified wit h glucose, galactose and mannose were 6.8, 2.8 and 2.0 g L(-1) h(-1), respectively. However, when these sugars were fermented along with a g lucose cosubstrate, the rate at which the combined glucose/mannose med ium was fermented was nearly identical to that of the glucose control.