Enhanced biodegradation of high molecular weight PAHs using yeast consortia immobilized on modified biowaste material

Abstract

The degradation of high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAHs) viz. benzo[a]pyrene, perylene and benzo[ghi]perylene in soil was studied using yeast consortia immobilized on various conventional matrices and biowaste materials. Enhanced biodegradation was noted using yeast consortia immobilized in sawdust powder (SDP) which was chemically modified (M-SDP). The chemical modification destroyed the benzene rings in the cellulose and improved the porosity of SDP by decreasing the crystallinity of the biomass. The physicochemical properties of M-SDP were characterized with SEM, EDAX analysis, FTIR analysis, X-ray diffraction and TGA analysis. Application of M-SDP showed enhanced degradation of benzo[a]pyrene (82.5%) followed by perylene (75.1%) and benzo[ghi]perylene (63.4%) after 40 days of incubation. The results of kinetic study demonstrated that HMW PAHs degradation in soil fitted the first order kinetic model. It can be concluded that chemically modified SDP can serve as potential immobilization matrix for supporting pollutant-degrading yeast consortia which can be employed for effective degradation of HMW PAHs.