Development of cost-effective medium for the large-scale production of a mosquito pupicidal metabolite from Pseudomonas fluorescens Migula

Abstract

Although Bacillus thuringiensis and Bacillus sphaericus are being used extensively for mosquito control, the recent reports of development of resistance in insects against them prompted many workers to search for new microbial agents or their metabolites for mosquito control. This has resulted in the isolation of a new bacterial isolate Pseudomonas fluorescens Migula which is known to be toxic against larval and pupal stages of mosquitos and could be considered for further development as a biocontrol agent. But the large-scale production of this bacterium is expensive because the high cost of the medium restricts this bacterium is used in mosquito control programs. In this study, we attempted to develop a cost-effective medium, based on inexpensive, locally available raw material Soya bean (Glycine max) by using 100-L bioreactor. Biomass and pupicidal metabolite production were satisfactory after P. fluorescens was produced on both media. Results showed that the Biomass in dry weight of Soya medium was 12.7 g/L and GPS medium (conventional medium) was 11.23 g/L. The maximum pupicidal metabolite production in Soya medium was (LC50 0.24 μL/mL) and in GPS medium was (LC50 0.44 μL/mL).