Production, Partial Purification and Characterization of Two α-Amylase Isoforms from Saccharomyces cerevisiae strain YOP 1/2-2 Isolated from Tchapalo (Côte d’Ivoire)

Abstract

Amylases play an important role in biotechnology and find applications in several industrial fields such as pharmaceutical, food, paper, cosmetics and detergents. Thus, it appears necessary to identify new sources of amylase, especially from microbial origin, due to the low energy consumption, cost-effective, high metabolic diversity, rapid cell growth, non-toxic and eco-friendly characteristics. In the present report, we carried out the production and partial purification of α-amylase by Saccharomyces cerevisiae strains isolated from Tchapalo, a traditional alcoholic beverage of Côte d'Ivoire. Five fungal isolates were screened initially for α-amylase production by using method of wells on Yeast Extract Peptone Dextrose Agar medium, a complete medium for yeast growth. One step DEAE-Sepharose Fast Flow was achieved for partial purification of α-amylase obtained. Among yeasts, isolate S. cerevisiae YOP 1/2-2 was able to provoke starch hydrolysis halo of 15.067±0.12 mm on starch agar plate after 48 h of incubation at 30°C. The partial purification of resulting enzyme showed two protein peaks, designated α-amylase 1 (AMY1) and α-amylase 2 (AMY2) with amylolytic activity and specific activities of 1.57-1.58 U/mg protein. Both isoforms (AMY1 and AMY2) were thermostable with optimal activity at 50 and 55°C, respectively, and at pH ranged from 4.5 to 5.3 in 0.1 M sodium acetate buffer. EDTA and Cd2+ strongly inhibited α-amylase activity by 72-75% and 64-65%, respectively, whereas cations Ca2+ and Mn2+ showed 85-99% and 71% increased amylolytic activity, respectively. All these properties show the potential uses of α-amylases from S. cerevisiae in the industrial transformation of starch.