A strain of Saccharomyces cerevisiae which grows efficiently on starch

Abstract

Saccharomyces cerevisiae BRG 530 is a meiotic segregant of S. cerevisiae NCYC 361 (syn. Saccharomyces diastaticus ). While NCYC 361 grew poorly on soluble starch, BRG 530 utilized 62% of starch for growth in batch culture, yielding 0.86 g biomass (g starch used) −1 . In comparison, Lipomyces kononenkoae CBS 2514, which produces α-amylase (1,4-α- d -glucan glucanohydrolase, EC 3.2.1.1) in addition to glucoamylase (1,4-α- d -glucan glucohydrolase, EC3.2.1.3) and possesses debranching activities, utilized starch more completely (92%). However, with CBS 2514, the specific growth yield was lower than with BRG 530 at 0.65 g biomass (g starch used) −1 , and only 15% of L. kononenkoae biomass was protein compared with 41% for the S. cerevisiae strain. Therefore, even with incomplete utilization of substrate, BRG 530 was more efficient in producing yeast protein from starch. More complete (96%) utilization of starch by BRG 530 was achieved by adding α-amylase; this has little effect on the efficiency of substrate conversion to biomass. The properties of BRG 530 suggest that a strain of S. cerevisiae could be developed for the production of yeast single-cell protein or other growth-associated products from starchy substrates.