Heat activation and stability of amylases from Bacillus species

Abstract

Leitch and Collier sporulating Bacillus medium was used to isolate some strains of Bacillus species from soil, wastewater and food sources in Ibadan, Oyo State, Nigeria, by heat activation method. Heat treatment at 80oC allowed the growth of sporulating Bacillus species, in the culture sample source without other bacteria forms. The amylolytic Bacillus species isolated during the study were identified as Bacillus macerans, Bacillus coagulans Bacillus licheniformis, Bacillus circulans, Bacillus megaterium, Bacillus polymyxa and Bacillus subtilis. Heat treatment at 70oC denatured the -amylase component of the amylase source while -amylase retained its potency at this temperature. Calcium cations (Ca2+) enhance the enzyme production than Na+ which was less effective. Physiological studies show that an optimum temperature of 40oC was suitable for the enzyme activity while temperature above 60oC reduced its activity unless positive measures are taken to stabilize it with relevant cations like Ca2+.