Screening of presumptive amylase-producing bacillus bacteria isolated from soil containing dairy food waste

Abstract

Soil microorganisms can produce amylase, especially the Bacillus strains bacteria. Amylase-producing bacteria can be obtained from soil containing properly composted dairy food waste. This study aims to analyse amylase-producing bacteria obtained from soil contaminated with dairy food waste. The soil sample was collected in three different settings which were A: normal soil without food waste, B: soil with yoghurt-based dairy food waste and C: soil with mixed dairy food waste. The isolation of bacteria was done and screened for α-amylase-producing bacteria using a starch hydrolysis test. Based on the result, a total of 17 gram-positive isolates were identified. They were classified into spore-forming and catalase-positive bacteria. Nevertheless, seven out of 17 isolates showed a positive for amylase production. Presumptive identification of the soil sample showed that soil A contain amylase-producing bacteria presumably non-Bacillus spp. In contrast, soil samples B and C, which after being contaminated with dairy food waste contain amylase-producing bacteria most likely Bacillus spp. As exhibited by the characteristics of isolates B1, B3, B7, and C3. In conclusion, the amylase-producing bacteria from soil contaminated with dairy food waste were identified and classified.