Lactose/whey fermentation and single cell protein production by auxotrophic mutants of Schizosaccharomyces pombe

ABSTRACT

Different auxotrophic mutants of Schizosaccharomyces pombe derived from argon irradiation and ethyl methanesulfonate [EMS] treatments were tested for single cell protein [SCP] production and also for the fermentation of lactose/whey as the agro-industrial wastes produced in very large quantities by the diary industry and often comes to be an environmental threat. Some of these mutants and prototrophic isolates were found to induce high yield of biomass and SCP. In addition, many of isolates, which have a higher yield of biomass, proved to give the highest yield of protein. Fermentation studies of lactose/whey showed that some of auxotrophic mutants could efficiently utilize lactose as a carbon source and grow well in whey medium. Although most of the mutants were significantly assimilated and bioconverted lactose, they significantly decreased residual lactose. Analysis of variance showed significant differences for lactose consumption and residual lactose. Auxotrophic mutants were utilized up to 65% of lactose in whey medium, 71% whey + 0.4% lactose and 76% in whey + 0.4% glucose. The results indicated that the biomass of yeast cells produced by the efficient strains of Schizosaccharomyces pombe through the fermentation of lactose/cheese whey might be considered as a protein source for marine and animal feeding. The utilization of these waste materials decreases pollution problems