Biodegradation of monocrotophos, cypermethrin & fipronil by Proteus myxofaciens VITVJ1: A plant - microbe based remediation.

Current study was focused on the degradation of pesticides such as Monocrotophos, Cypermethrin & Fipronil (M, C & F) using phyto and rhizoremediation strategies. The isolate Proteus myxofaciens (VITVJ1) obtained from agricultural soil was capable of degrading M, C & F. The bacteria exhibited resistance to all the pesticides (M, C & F) up to 1500 ppm and was also capable of forming biofilms. The degraded products identified using Gas Chromatography-Mass Spectroscopy (GC-MS) and FTIR was further used for deriving the degradation pathway. The end product of M, C & F was acetic acid and 3-phenoxy benzoic acid which was confirmed by the presence of functional groups such as C=O and OH. Seed germination assay revealed the non-toxic nature of the degraded products with increased germination index in the treatments augmented with degraded products. The candidate genes such as opdA gene, Est gene and MnP1gene was amplified with the amplicon size of 700bp, 1200bp and 500bp respectively. P. myxofaciens not only degraded M, C & F, but was also found to be a plant growth promoting rhizobacteria. Since, it was capable of producing Indole Acetic acid (IAA), siderophore and was able to solubilize insoluble phosphate. Therefore, VITVJ1 upon augmentation to the rhizoremediation setup aided the degradation of pesticides with increase in plant growth as compared to that of the phytoremediation setup. To our knowledge this is the first study where P. myxofaciens has been effectively used for the degradation of three different classes of pesticides, which could also enhance the growth of plants and simultaneously degrade M, C & F.

Biosurfactant mediated bioelectrokinetic remediation of diesel contaminated environment.

The present study integrated the electrokinetic (EK) with bioremediation (Bioelectrokinetic -BEK) of diesel hydrocarbon by Staphylococcus epidermidis EVR4. It was identified as efficient biosurfactant producing bacteria and growth parameters was optimized using response surface methodology. Upon degradation, there is a complete disappearance of peaks from nonane (C9) to tricosane (C23) and 85%, 47% of degradation of pentacosane and octacosane respectively. Marine bacterial strain, EVR4 was found to be potential to degrade the diesel with a maximum degradation efficiency of 96% within 4 d, which was due to its synergistic role of biosurfactant and catabolic enzymes (dehydrogenase, catalase and cytochrome C). The application of integrated BEK was an effective insitu method for the remediation of diesel contaminated soil by BEK (84%) than EK (67%). EVR4 as an effective strain can be employed for BIO-EK method to clean the diesel hydrocarbon polluted environment.