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Microorganisms with high oil-degrading ability are essential for bioremediation of oil-contaminated environments and oil spills. In the present study, a microbial consortium was enriched from a long-term oil-contaminated soil by acclimatization with crude oil, and was cultured with sucrose as a carbon source. Immobilization of the microbial consortium cells was prepared onto sodium alginate (SA) beads. To enhance the mass transfer of the immobilized microspheres, activated carbon, biochar, corn stalk and sawdust were used, respectively, to accelerate the degradation of petroleum hydrocarbons. The immobilized beads and the distribution of microbial cells inside the immobilized beads were examined using scanning electron microscopy (SEM). The degradation efficiency of total petroleum hydrocarbon (TPH) by different immobilized beads in aquatic systems (mineral salt medium, artificial seawater) was evaluated by gravimetric method after 7 d of incubation. Results showed that TPH degradation efficiency of the immobilized beads was higher than that of the microbial culture, and that of the immobilized beads containing adsorbent carriers was higher than the SA immobilized beads. The highest TPH degradation efficiencies of SA-CS immobilized beads in mineral salt and artificial seawater were up to 54.2% and 50.5%, respectively, and the highest TPH degradation efficiency of biostimulation + SA-AC immobilized beads treatment in oil-contaminated soil was up to 63.7% after 10 weeks of incubation. Our results suggest that the immobilized microorganism is a promising approach for a wide range of bioremediation applications in different petroleum-contaminated environments.

Biosurfactant lipopeptide is a promising dispersant over varieties of chemical ones in oil-spill remediation. The toxicity, biodegradability and performance of the biosurfactant lipopeptide are studied in this paper.

Bacterial community and diversity in a long-term petroleum-contaminated soil of an oilfield were characterized using 16S rRNA gene-based Illumina MiSeq high-throughput sequencing. Results indicated that Proteobacteria (49.11%) and Actinobacteria (24.24%) were the most dominant phyla, and the most abundant genera were Pseudoxanthomonas (8.47%), Luteimonas (3.64%), Alkanindiges (9.76%), Acinetobacter (5.26%) and Agromyces (8.56%) in the soil. Meanwhile a series of cultivations were carried out for isolation of alkane degraders from petroleum-contaminated soil with gellan gum and agar as gelling agents. And the isolates were classified by their 16S rRNA genes. Nine of the isolates including Enterobacter, Pseudomonas,Acinetobacter, Rhizobium, Bacillus, Sphingomonas, Paenibacillus, Variovorax and Rhodococcus showed strong biodegradability of alkane mixture (C9-C30) in a wide range of chain-length, which could be potentially applied in enhancement of bioremediation.