High-effective Hydrocarbon-degrading Bacteria:Domestication,Degradation Characteristics and Preliminary Application
Microbial technology is of a broad application prospect in the remediation of oil-contaminated soil,and obtaining the bacteria(microbial communities)of high degradation efficiency is the key to ensuring efficient remediation.In this study a microbial consortium(named No.1)with stable and efficient capacity of degrading petroleum hydrocarbons was do-mesticated from four different kind of oil-contaminated soil,and the high-throughput sequencing was conducted to de-termine the composition of the consortium;the effects of different environmental factors on the petroleum hydrocarbon degradation capacity of the No.1 consortium were investigated,and the optimal degradation condition was determined;fur-thermore,the degradation characteristics and kinetics were analyzed,and the potential application of the No.1 consortium to the soil heavily polluted by oil was explored,which involved the consortium being immobilized on broken buckwheat husks and then was used to remediate the combined soil pollution of petroleum hydrocarbon and cadmium.Consequently,the study showed that the No.1 consortium was mainly composed of Stenotrophomonas,Pseudomonas,Ochrobactrum,Lactoba-cillus and Achromobacter,and after 10 days cultivation,as crude oil concentration in the polluted soil sample was 0.5％,and under the optimal condition:1％salinity,pH of 8,temperature of 35 ℃,C:N:P as 100:2:1,and ammonium nitrate being as the nitrogen source,the degradation rate of the consortium increased from 52.1％to 76.6％;the results of GC-MS analysis showed that the average degradation rates of C13～C26 alkanes by the consortium were 90.3％and 97％after 9 and 24 days of cultivation,respectively,indicating that the medium and long-chain alkanes were rapidly and efficiently degraded;and the degradation of crude oil by the consortium fit the first-order kinetics when the initial concentrations were 0.5％and 4％.In addition,when the consortium was inoculated into polluted soil with initial petroleum hydrocarbon content of 4 631 mg/kg and 8 591 mg/kg,after 40 days it was found the degradation rates were respectively 47.7％and 26.4％.The immobilized con-sortium applied to the remediation of combined hydrocarbon/cadmium polluted soil was better than others(without being im-mobilized)in terms of degradation rate of petroleum hydrocarbon,soil dehydrogenase activity,and catalase activity,but the concentration of exchangeable cadmium was lower.The results obtained so far from the experimental study demonstrate the potential application of the microbial consortium to the remediation of heavy oil-polluted soil and soil contaminated by petro-leum hydrocarbon and cadmium.
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