Isolation and Identification of Yeast Strains Capable of Producing Single Cell Protein from Whey in Co-Cultures with Saccharomyces cerevisiae

In this study, twenty-five whey samples collected from dairy industries in the city of Isfahan. The sampleswere cultured on malt extract broth (MEB) and yeast extract glucose chloramphenicol agar (YGCA) media.Eleven yeast strains (designated M1 to M11) were isolated from the culture. The strains were identified bytheir morphological and physiological properties. Betagalactosidase activity in the yeast strains showed thata strain of K. lactis designated as M2 had highest enzyme activity (up to 8103 EU/ml). The isolated yeaststrains were examined for their ability in reduction of the biological oxygen demand (BOD). The resultsdemonstrated a high level of reduction in the M2 strain.This strain was also found to have highest level of single cell protein (SCP), production (up to 11.79 g/l drymass cell). The co-culture of the isolated yeast strains with Saccharomyces cerevisiae resulted in the highestbiomass yield up to 22.38 g/l dry mass cell and significant reduction in initial BOD. Together, the datashowed that the isolated yeast strain could be of valuable application in bioconversion of whey.