Bioremediation of lambda cyhalothrin by Bacillus inaquosorum and Bacillus spizizenii isolated from surface of Thompson seedless grape berry.

Abstract

Lambda cyhalothrin is frequently used to combat defoliating insects, especially beetles, however it also has a significant impact on naturally occurring non-target species. Two grape epiphytic bacteria, Bacillus inaquosorum strain LC1 and Bacillus spizizenii strain LC2, were found to degrade lambda cyhalothrin. The biodegradation of pesticide in a liquid medium, in soil and on grape berries was investigated. In liquid medium on day 0, approximately 4.5 µg/ml of lambda cyhalothrin was detected in all the test and control broth. The concentration of lambda cyhalothrin in control, LCI treated broth and LC2 treated broth was 3.66 µg/ml, 1.83 µg/ml and 1.41 µg/ml respectively, after 10 days. Maximum degra- dation of lambda cyhalothrin was shown by LC2 bacteria in comparison to control. During the field study, the average degradation of lambda cyhalothrin for both the years was 66.13% by isolate LC 1 and 80.79% by LC2. The average natural degradation of lambda cyhalothrin was 37.50% in control. The degradation efficiency of LC1, when compared to autoclaved soil, was high in non-autoclaved soil. indicating that the natural microflora of soil affected the degradation process of LC1. On the other hand, the degradation efficiency of LC2 in non-autoclaved soil and on grape berries was high which suggested that the bacteria were able to live through, in addition to competing with other microorganisms under field environment.