Production of alpha-amylase from a novel strain of Bacillus licheniformis on low-cost substrates

Amylase is an industrially important enzyme that can be utilised in various industrial processes, including those in the food, animal feed, pharmaceutical, detergent, textile, and paper industries. In this study, the isolate SHB17_28, which exhibited the highest α-amylase production among the isolates obtained through garden soil screening, was identified as Bacillus licheniformis based on its phenotypic characteristics and 16S rRNA gene sequencing. Six agro-industrial wastes, namely beet molasses, brewer’s malt, grape waste, corncob, wheat straw, and wheat bran, were evaluated as substrates for α-amylase production. Optimal conditions for α-amylase production by the strain were pH 8, 35°C, 48 h of incubation, and a shaking speed of 120 rpm. Of the agro-industrial waste material, grape waste (1.5% w v-1) and beet molasses (2% w v-1) yield the greatest α-amylase as carbon sources. Amylase was stable at 50°C, pH 8, and in a medium containing 5 mM of various metal ions. Overall, it was concluded that α-amylase from a new strain of Bacillus licheniformis could be produced at a low cost using agro-industrial waste materials, thereby eliminating the need for expensive growth factors.