Production and evaluation of a yeast utilizing an industrial waste

Abstract

Pichia pinus was grown in a semi-continuous process on mango-peel extract medium. The yield was 8 g/litre after 12 h at the end of the logarithmic phase. The biomass of Pichia pinus contained 53·7% protein. Amino acid analyses of the protein revealed the presence of all amino acids in substantial amounts except for those containing sulphur, which were the limiting amino acids. When fed to rats the protein biomass exhibited good nutritional values (protein efficiency ratio, 2·77 ± 0·126; apparent digestibility, 71·54 ± 1·02) as compared to the casein diet (protein efficiency ratio, 2·913 ± 0·127; apparent digestibility, 90·156 ± 0·64). Alkaline phosphatase levels were insignificantly different from the control during the experimental period (21, 28, 35 and 42 feeding days). The transaminases, γ-glutamyl transferase activities and creatinine levels in the serum were significantly varied at the 35th and 42nd feeding days. The glutamate oxaloacetate transaminase, urea and uric acid levels in serum were significantly increased only after 35 feeding days. No histological changes were observed in either liver or kidney tissues.