Document Type: Research Paper
Department of Biology, Faculty of Science, Isfahan University, Isfahan, I.R. Iran.
Department of Biology, Faculty of Science, Shahid Chamran University, Ahwaz, I.R. Iran.
In this study, twenty-five whey samples collected from dairy industries in the city of Isfahan. The samples
were 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 by
their morphological and physiological properties. Betagalactosidase activity in the yeast strains showed that
a strain of K. lactis designated as M2 had highest enzyme activity (up to 8103 EU/ml). The isolated yeast
strains were examined for their ability in reduction of the biological oxygen demand (BOD). The results
demonstrated 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 dry
mass cell). The co-culture of the isolated yeast strains with Saccharomyces cerevisiae resulted in the highest
biomass yield up to 22.38 g/l dry mass cell and significant reduction in initial BOD. Together, the data
showed that the isolated yeast strain could be of valuable application in bioconversion of whey.