α-Amylase Production on Low-Cost Substrates by Naxibacter sp. Isolated from Mauritian Soils

Alpha amylase is an important enzyme used in different industries, which degrades starch into smaller disaccharides. Extracellular α-amylase producing organisms were isolated from soil samples from Mauritius and identified by standard biochemical tests. In this study, the high yielding strain was used for amylase production. The potential of four readily available substrates, namely sugarcane bagasse, potato peel, kitchen wastes and banana peel to induce amylase production was investigated. Different parameters like temperature (30ºC, 40ºC, 50ºC, 60ºC & 70ºC), different pH (5.0, 6.0, 7.0, 8.0 & 9.0) and inoculum sizes (10%, 20%, 50%, 100% & 150% v/w) were used for the α-amylase production. It was found that α-amylase production and activity was highest for potato peel at 50ºC at pH 6.0 and inoculum size 50% (v/w). Amylase assays performed at different incubation temperatures (30ºC - 60ºC) and pH (5-9) showed that the amylase worked best at 50ºC and pH 7.Based on results of biochemical tests and 16S ribosomal RNA gene sequences, the isolate was identified to belong to the Betaproteobacteria, closely related to Naxibacter haematophilus (99% sequence similarity to the type strain).