Sodium dodecyl sulphate polyacrylamide gel electrophoresis of toxin proteins of Bacillus thuringiensis isolated from soil at the Liwa Botanical Garden

Bacillus thuringiensis is a spore-forming bacterium known to have the ability to synthesize proteins that are toxic against insect pests. Currently, the bacterial protein toxins are widely used as pesticides because they are environmentally friendly and safe for health. As a cosmopolitan microbe B. thuringiensis is widely distributed in nature with soil as its main habitat. Liwa Botanical Gardens is one among the conservation areas in Lampung Province of Indonesia where the soil type and conditions expected to good for the bacterial life of B. thuringiensis. This study aims to determine toxin proteins extracted from B. thuringiensis isolated from the soil of the Liwa Botanical Garden by their molecular weights. The proteins were quantified using Lowry method and the protein profiling performed using SDS PAGE electrophoresis. The results showed that there were two isolates, Bt 3 and Bt 5 which showed close protein concentrations, namely 0.679 mg/ml and Bt 5 with 1.313 mg/ml respectively. Both isolates also exhibit different molecular weights. Bt 3 isolate has a molecular weight of 110.59 kDa, while Bt 5 has a molecular weight of 76.97 kDa.