Abstract

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The search for novel microorganisms with enhanced amylase production is a continuous process, and the starch-based agrowastes (SBAW) hold such potential. This study investigated the ability of bacteria isolated from SBAW obtained locally to produce extracellular amylase with varying cultural conditions. A total of 41 bacteria isolated by spread-plate from the SBAW samples were identified using their morphological, biochemical and 16S rRNA gene characteristics. Preliminary screening by starch hydrolysis revealed three most-promising amylolytic isolates with 5.0 – 6.0 mm clear zone diameter. They were Myroides odoratimimus BY-F1, Enterobacter asburiae YP-F1 and Bacillus cereus CP-A4 with the amylase production of 308.75 ± 1.41 U/ml, 274.44 ± 0.68 U/ml and 205.83 ± 0.18 U/ml respectively. Their optimal culture conditions were BY-F1 [pH 7.0 at 40°C for 72 h], YP-F1 [pH 9.0 at 40°C for 24 h] and CP-A4 [pH 9.0 at 35°C for 72 h]. The FTIR characterisation of the amylase purified by Calotropis procera latex and activated charcoal revealed the presence of -OH, -COOH and -NH2 group, which are essential for amylase activity. The findings suggest the exploitation of Myroides odoratimimusBY-F1, Enterobacter asburiae YP-F1 and Bacillus cereusCP-A4 for industrial-scale production of extracellular amylase.

Keywords: amylase, amylolytic activity, starch-degrading bacteria, agricultural wastes, enzyme