Studies on Baker's Yeasts of East Pakistan

SUMMARY

Seventy-nine strains of yeast have been isolated from dough from different districts of East Pakistan. Forty-two isolates belong to Saccharomyces carlsbergensis, twenty-six to S. cerevisiae var.ellipsoideus, seven to S cerevisiae, two to Candida Guilliermondii and two to Rhodotorula glutinis. The two Rhodotorulas are considered to be contaminants. The isolation of S. carlsbergensis from dough is reported for the first time.

Nineteen isolates have proved to be autotrophic, fifty-eight deficient for pantothenic acid, twenty-two deficient for biotin, twelve deficient for pyridoxin, eleven deficient for inositol, eight deficient for nicotinic acid, five deficient for thiamin and three deficient for riboflavin.

Six strains of yeast have been studied further. The strain of S. cerevisiae var.ellipsoideus analyzed is heterozygous for the fermentation of raffinose, galactose and α-methyl glucoside and the synthesis of riboflavin. One strain of S. carlsbergensis is heterozygous for galactose fermentation. Heterozygosity for the synthesis of pantothenic acid and pyridoxin has been seen in one strain; for pantothenic acid, inositol and thiamin in another strain; and for biotin, nicotinic acid and riboflavin in a third strain of S. carlsbergensis.