PRODUCTION OF BIOSURFACTANT FROM BACILLUS SP. AND ITS LARVICIDAL ACTIVITY

Mosquitoes are becoming a serious threat to the humans causing infectious diseases like dengue, malaria, chikungunya, yellow fever etc. They multiply in large numbers in a polluted environment and stagnant water bodies. The control measures include the use of pesticides and chemical compounds which further causes harmful effects. Thus, an alternative solution is to use a biologically active compound which has larvicidal property and is eco-friendly. Biosurfactants are such compounds. In this present study, 75 isolates obtained from petroleum contaminated soil samples were screened and one potent isolate was selected and identified. The biosurfactant was produced from Bacillus subtilis B50. The crude compound was characterized as lipopeptide. Its larvicidal activity was tested using the similar stage of mosquito larvae at different concentration of crude biosurfactant (1 – 10 mg %). The LC₅₀ and LC₁₀₀ were calculated after observing the larvae for 72 h. The obtained results showed that as the time and concentration increases the mortality also increases. The maximum number of larvae was killed at a concentration of 1 – 4 mg for 72 h. The observations suggest the application of biosurfactant as an eco-friendly product for the eradication of mosquitoes