Study on bioadsorption and biodegradation of petroleum hydrocarbons by a microbial consortium

A microbial consortium isolated from Shengli oilfield polluted sludge was capable of degrading naphthalene (NAP), phenanthrene (PHE), pyrene (PYR) and crude oil. It performed high biodegradation activity and emulsifiability for petroleum hydrocarbons, and was tolerant to 6.2 mM Cu2+, 2.7 mM Zn2+ and 9.5 mM Pb2+. Biodegradation rates of NAP, PHE, PYR and crude oil were 53%, 21%, 32% and 44% in the presence of heavy metal (Cu2+, 1.7 mM and Zn2+, 2 mM), respectively. Exploration on the adsorption and uptake of petroleum hydrocarbons by microbe suggested the stability of surface adsorption and cell uptake by live microbial consortium followed a decreasing order of NAP > PHE ≈ PYR > crude oil. The adsorption by heat-killed microbial consortium was constant for PAHs, while decreased for crude oil. Experiments on enzymatic degradation indicated that the metabolic efficiency of periplasmic, cytoplasmic and extracellular enzymes secreted by the microbial consortium for diverse substrates was different.