Ethanol from lactose in salted cheese whey by recombinant Saccharomyces cerevisiae

Seven yeast recombinants were selected from 57 fusant colonies on the basis of higher DNA content, nuclear diameter and ethanol yield compared to pare ntal Saccharomyces cerevisiae ATCC 4126 and Kluyveromyces lactis CBS 683. S ix recombinants out of the above colonies revealed growth on lactose and su crose, indicating that they are S. cerevisiae with transformed beta-galacto sidase systems. The fusant colonies were investigated with respect to their capacity to convert lactose in salted cheese whey into ethanol. Among thes e recombinants that showed high tolerance towards sodium chloride and highe r ethanol yield than lactose fermenting parental K. lactis CBS 683, SK-1 ex hibited high tolerance up to 4 g dl(-1) sodium chlonride with an ethanol yi eld of 4.66 ml dl(-1) (v/v), SK-23 tolerated 6 g dl(-1) sodium chloride wit h an ethanol yield of 4.14 mi dl(-1) (v/v) and SK-26 showed resistance towa rds 8 g dl(-1) sodium chloride and give an ethanol yield of 3 mi dl(-1) (v/ v).