Kluyveromyces lactis– a retrospective

The use of Kluyveromyces lactis for research started in early 1960s. In contrast to most cases of yeast research, the study of this particular species was initially motivated by a purely academic question, that is, possible adaptive regulation of sugar metabolism in a lower eukaryote. Biotechnological interest in K. lactis came much later. Until about 1980, K. lactis research was barely visible in the shadow of the formidable development of the Saccharomyces cerevisiae system. The early 1960s were the era of lactose regulation in Escherichia coli , which led to the birth of molecular biology. Following the achievements of the investigators of the E. coli system, a number of laboratories were trying to find an inducible enzyme system in a eukaryotic organism in order to evaluate the general significance of the operon concept. Harlyn O. Halvorson at Madison, Wisconsin, was one of those people. He contacted the great taxonomist L. J. Wickerham (USDA, Peoria) who knew how different yeast species assimilated various sugars. Apparently, it was he who suggested the use of K. lactis , a species that assimilated β-glucosides in an adaptive mode. Halvorson and his colleagues have thus started to work on this yeast (then called Saccharomyces lactis ), using two isolates obtained from Peoria, NRRL Y-1140 (CBS 2359 [ Mat a ]) and …