Produksi Bioinsektisida Dari Bacillus thuringiensis subsp. aizawai Menggunakan Limbah Industri Tahu Sebagai Substrat.

Abstract

This research was to obtain the best media formulation oftions for bioinsectisides production using Bacillus thuringiensis subsp. aizawai and to asses the level of toxicity against larvae Crocidolomia binotalis (cabbage worms). Media formulation oftions using tofu waste and tofu waste water, with a ratio of 20: 80, 30: 70, and 40: 60 and the amount of starters added 10, 15, and 20 (% v /v). Observations done at 0, 30, and 48 hours of the cultivation time which include pH, total residual sugar, the total plate count, and the viable spore count. Toxicity tests were conducted by bioassay using larvae Crocidolomia binotalis (cabbage worms). The analysis of raw materials obtained on the carbon content of tofu waste and tofu waste water at 5.64% (wb) and 0.27% (wb), while the nitrogen content of 0.42% (wb) and 0.02% (wb). During the cultivation, the pH in the cultivation liquid was increased while total sugars is decreased. The pH values during cultivation was ranging from 7.27 to 8.21. Efficient use of substrate for cultivation 30 hours ranged from 13.14% (C2) to 33.61% (A3) and for cultivation 48 hours ranged from 31.73% (C3) to 41.91% (B3). The highest total plate count in this research is media formulation of B3 (2.14 x 108 cells/ml) with cultivation time during the 48 hours, whereas the lowest total plate count in this research is media formulation of A3 (1 x 107 cells/ml) with cultivation time during the 48 hours. The highest amount of viable spore count in this research is the media formulation of B2 (2.95 x 107 spores/ml) with cultivation time during the 48 hours, whereas the lowest viable spore count in this research is the media formulation of A1 (1.25 x 106 spores/mL) with cultivation time during the 48 hours. Cultivation during 30 hours using media formula A1 produces crystal protein in high toxicity to Croccidolomia binotalis larva. This is indicated by the highest toxicity level from bioassay test which shown by medium formulae of A1, which was 1,34 mg/L, and the lowest toxicity level was shown by media formulae of C3, which was 174,16 mg/L. Whereas cultivation during 48 hours using media formulation of A2 produces crystal protein in high toxicity to Croccidolomia binotalis larva. This is indicated by the highest toxicity level from bioassay test which shown by medium formulae of A1, which was 7,44 mg/L, and the lowest toxicity level was shown by media formulae of C3, which was 45636,00 mg/L. In the control (distilled water + prostiker) who were not given fluids bioinsectiside products not found of C. binotalis larva is dead, while in the commercial product (Bactospeine) toxicity was obtained at 0.05 mg / L with potential products 16 000 UI / mg.