Bioaugmentation: a strategy for enhanced degradation of pesticides in biobed.

Biopurification system (BPS) or biobeds are low-cost system for decontamination of on-farm generated pesticide waste. A biobed contains a mixture of soil, lignocellulosic biomass and organic matter source (compost/peat) and works on the principal of retention of pesticide in high organic matter matrix and its subsequent degradation by microbes. Bioaugmentation, a green technology, is defined as the improvement of the degradative capacity of biobeds by augmenting specific microorganisms. During last 20 years, several studies have evaluated pesticide degradation in biobeds augmented with bacterial and fungal species and prominent microorganism include genus Pseudomonas, Sphingomonas, Arthrobacter, Phanerochaete, Stereum, Delftia, Trametes, Streptomyces etc. Degradation of pesticides belonging to major classes have been studied in the bioaugmented biobeds. Studies suggested that some pesticides were degraded faster in the bioaugmented biobeds subject to survival and proliferation of degrading microbe. However, no effect of bioaugmentation was observed on degradation of some pesticides and no clear reason for the same was evident. Bioaugmentation with pesticide degrading microorganisms/consortium in combination with rhizosphere-assisted biodegradation could be an optimal strategy for accelerating the degradation of pesticides in biobeds.