Enhanced Chrysene Degradation by a Mixed culture Biorem-CGBD using Response Surface Design

Abstract

Degradation of chrysene, a four ringed highly carcinogenic polycyclic aromatic hydrocarbon (PAH) has been demonstrated by bacterial mixed culture Biorem-CGBD comprising <i style="mso-bidi-font-style: normal">Achromobacter xylosoxidans, Pseudomonas </i>sp. and <i style="mso-bidi-font-style:normal">Sphingomonas </i>sp., isolated from crude oil polluted saline sites at Bhavnagar coast, Gujarat, India. A full factorial Central Composite Design (CCD) using Response Surface Methodology (RSM) was applied to construct response surfaces, predicting 41.93% of maximum chrysene degradation with an experimental validation of 66.45% chrysene degradation on 15^th day, using a combination of 0.175, 0.175 and 0.385 mL of OD₆₀₀=1 inoculum of <i style="mso-bidi-font-style:normal">A. xylosoxidans, Pseudomonas </i>sp. and <i style="mso-bidi-font-style:normal">Sphingomonas </i>sp., respectively and a regression coefficient (<i style="mso-bidi-font-style:normal">R²</i>) of 0.9485 indicating reproducibility of the experiment. It was observed that chrysene degradation can be successfully enhanced using RSM, making mixed culture Biorem-CGBD a potential bioremediation target for PAH contaminated saline sites.