Development of a Cheap Media for Bacillus thuringiensis Growth

Abstract

Bacillus thuringiensis (Bt) is being widely used in mosquito control programs. However, large-scale production of this bacillus is expensive due to the high cost of the production medium. In this study, we attempted to develop a cost-effective medium, based on locally available raw materials which is available in plenty as waste product from several industries. The results of the optimization studies showed that the optimum pH is at (7.2) and the optimum incubation temperature at (30˚C) using standard nutrient broth (NB) media. Raw materials (wheat bran, rabbit feed, cabbage leaves, potato tubercles, and cactus extracts as carbon and protein sources were tested. In addition, seawater and stock solution as mineral sources were also prepared to select the most appropriate growth media. 35 trials (single or in combination) from those materials were experimented. The growth was determined by spectrophotometer at 600 nm. Medium composed of cactus extract and seawater was shown to be superior to other media for the growth of B. thuringiensis. In conclusion, the finding of this cheap formulation should contribute to the reduction of the cost of B. thuringiensis bioinsecticide production. This would encourage local large scale production 221