Abstract
Food yeast, Mycotorula japonica is a rich source of protein, but is hard to be digested. The yeast previously removed nucleic acid was treated at 37°C, for 20 hours in water solution with crude β-D-1, 3-glucanase preparation produced by mold, Sclerotinia Libertiana. Around 50% of crude protein (as nitrogen) originally present in the yeast was extracted by the first treatment.
From the residue, another 40% of the protein fraction was extracted with 0.5N NaOH at 37°C for 3 hours. The protein fraction of the first extraction of the yeast by the treatment with the glucanase solution was purified alternately with cation and anion exchange resin column chromatography in the yield of 50%. The most of the ash in the protein fraction was removed.
The amino acid compositions of the crude protein fraction and the purified preparation were compared with those of the original yeast.
