Characterization of Novel Bacillus thuringiensis Isolated from Attacus atlas and Its Growth Kinetics in the Cultivation Media of Tofu Whey for Bioinsecticide Production

Abstract

Bacillus thuringiensis that produces endotoxins, can serve as active ingredients of biopesticide. Bacillus thuringiensis that previsiously have been  isolated from carrion worm of Attacus atlas. The characteristics of Bacillus thuringiensis isolates isolated from carrion worm of Attacus atlas from Bogor-Indonesia are  gram-positive, motile, punctiform, white and slimy, long and  round vegetative cells with a length of 1720 nm and a width of 836 nm. The protein crystals yielded are spherical, with a diameter of 770 nm. Genomic of DNA amplified using PCR with universal primers for 16S rRNA showed maximum similarity of 95% with a few lines of Bacillus thuringiensis. Philogenetikc tree reconstruction shows the isolates are in the same cluster with Bacillus thuringiensis. The kinetics growth of Bacillus thuringiensis on tofu whey as media results in parameter N-max 10.51 log CFU/mL, P-max 8.67 log CFU/mL, ?_N-max 0.052 h^-1, and (S₀-St)/S₀ 27.57%. Toxicity calculation on second instars larvae of Aedes aegepty from the  cultivation broth at the 24^th hour yielded LC₅₀ values of ?? 0.7 mg/mL and product potency of 2142 IU/mg.

Keywords: Bacillus thuringiensis, isolation, characteristics, kinetics, toxicity