Cultivation of Candida utilis on Cassava Peel Hydrolysates for Single-cell Protein Production

The growth of Candida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 °C, 33 °C and 41 °C. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate ( μ max ) was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient (Y x/s ) did not differ much in these two media. In the enzymatic hydrolysate, its Y x/s value on sugar was 0.44 with a μ max of 0.35 h -1 , whereas the corresponding values were 0.52 and 0.48 h -1 in the acid hydrolysate and 0.50 and 0.37 h -1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectivel y. The amino acid profile of th e yeast biomass compared favourab ly with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast sin gle cell protein by using