From Waste to Wealth: Efficient α-Amylase Production Using Agro-Waste Materials: A Study on Brevibacillus Isolates

Soil microbiota serves as a rich source of different microbial enzymes including α-amylase. In this study we aimed to isolate, optimize amylase-producing bacterial strains, and evaluate the effectiveness of agro-waste in replacing conventional starch-based fermentation substrates. Soil samples were collected from different areas of Pakistan. Bacteria that produce α-amylase were isolated and characterized. Initial screening in vitro was performed by starch hydrolysis assay. This process resulted in the identification of two promising bacterial isolates, AU1 and AU2, which were further characterized through biochemical testing and 16S rRNA sequencing. They were identified as Brevibacillus reuszeri and Brevibacillus brevis, respectively. Optimization of the fermentation conditions revealed optimal pH 7, temperature of 38 °C, incubation period of 72 h, and yeast extract as an organic nitrogen source. Additionally, using different agro-waste, general waste, and several sources of starch including corn comb, wheat bran, rice bran, potato peel, rice starch, potato starch, and corn starch, Brevibacillus reuszeri, and Brevibacillus brevis were tested for the production of α-amylase. The maximum amylase production was observed by Brevibacillus reuszeri with wheat bran (381 μmol/ min.) and Brevibacillus brevis with potato peel (395 μmol/ min.). Our research provides significant insights into the optimization of the fermentation processes for α-amylase production, highlighting the economic and sustainable potential of utilizing agro-waste materials in enzyme production industries.