BIOCONVERSION OF CHEESE WHEY TO BIOMASS AND BIOPROTEIN BY YEAST CULTURES

This research emphasizes on bioconversion of cheese whey by using of six yeast strains culture. Cheese whey, in Iran and Azerbaijan republic, is treated as a waste and discharged in nature approximately without any treatment which creates pollution problems. It is a by-product of the dairy industiy and contains usually high levels of lactose (4-6%), low levels of niti·ogenous compounds and small amounts of vitamins and minerals. Lactose, the main nuti·ient in cheese whey, can be economically utilized by its conversion to biomass and bioprotein. For this pmpose, 6 yeast sti·ains:Trichosporon pullulans, Candida curvata, Cryptococcus podzolicus, Bullera oryza, Cryptococcus laurentii and Cryptococcus jlavus were chosen among isolated yeasts from natmal habitats in different forest ecosystems, for their growth and single cell protein content on cheese whey. These yeast sti·ains were tested for their ability to produce SCP from cheese whey. Among these strains, Cryptococcus laurentii had themost SCP production from whey with the yield of 18.84 ± 0.50 g/lit. The emichment of cheese whey by minerals as niti·ogen somce increased biomass yield. Preliminaty tests in om laborat01y showed that among the chosen yeasts in this smvey, 2 yeast sti·ains ( C!yptococcus laurentii and Cryptococcus flavus respectively) as shown in the text had relatively high biomass production when cultivated on cheese whey. They were fmther grown on sterilized, non-sterilized and emichment fresh sweet cheese whey