Yeasts for single-cell protein production by soybean whey fermentation

In order to reuse the nature biomass and remove some COD in soybean whey, Geotrichum candidum link, Candida utilis, Candida tropicalis, Candida lipolytica var. lipolytica and Saccharomycopsis fibuligera were investigated for single-cell protein (SCP) production from soybean whey by batch fermentation. The results indicated that all the five yeasts could satisfactorily proliferate with an inoculant in the range from 0.3 to 0.4 mg/L. Among these five yeasts, C. lipolytica var. lipolytica and S. fibuligera were proved to be the feasible yeasts for SCP production from soybean whey. When the initial COD concentration was 111500 mg/L and the pH was 6.2, the SCP of C. lipolytica var. lipolytica reached the maximum of 2.35 g/L with a COD removal of 48.3% after being cultured in Erlenmeyer flask for 12 h at 25°C with rocking at 180 r/min. For 5. fibuligera, the SCP specific production rate during logarithmic phase, the protein content and the protein yield were 0.36 g/(L·h), 39.7% and 0.88 g/L, respectively, which were the maximum among the five yeasts.