Effects of Bacillus subtilis metabolites on larval Aedes aegypti L

• An extracellular secondary metabolites was purified from Bacillus subtilis a gram-positive isolates from the soil samples.
• The secondary metabolites were purified and molecular masses were determined through SDS–PAGE, 16S rRNA and HPLC.
• The lethal concentrations were identified for bioassay against the dengue vector Aedes aegypti.
• Effect of B. subtilis secondary metabolites was determined through AChE, α and β carboxylesterase, ACP and ALP.

The culture supernatant of a strain of Bacillus subtilis isolated from soil samples killed larvae of the mosquito Aedes aegypti. The metabolites produced by B. subtilis were characterized using high performance liquid chromatography (HPLC). Mortality rate was dose-dependent for all larval instars of A. aegypti. Log probit analysis (95% confidence level) revealed an LC50 of 1.73 and an LC90 3.71 μg/ml. Molecular weights/masses of B. subtilis metabolites were confirmed using SDS–PAGE analysis. B. subtilis metabolites were confirmed using HPLC analysis. We demonstrate that secondary metabolites from B. subtilis have larvicidal activity against A. aegypti and may be suitable for the control of this and other mosquito vectors of human disease. The larvae to the metabolites, significant reduction in the activities of acetylcholinesterse, α-carboxylesterase, and acid phosphatases were recorded.

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