Enhanced Biodegradation of High-Salinity and Low-Temperature Crude-Oil Wastewater by Immobilized Crude-Oil Biodegrading Microbiota

High salt and low temperature are the bottlenecks for the remove of oil contaminants by enriched crude-oil degrading microbiota in Liaohe Estuarine Wetland (LEW), China. To improve the performance of crude-oil removal, microbiota was further immobilized by two methods, i.e., sodium alginate (SA), and polyvinyl alcohol and sodium alginate (PVA+SA). Results showed that the crude oil was effectively removed by the enrichment with an average degrading ratio of 19.42–31.45 mg(L d)−1. The optimal inoculum size for the n-alkanes removal was 10% and 99.89%. Some members of genera Acinetobacter, Actinophytocola, Aquabacterium, Dysgonomonas, Frigidibacter, Sphingobium, Serpens, and Pseudomonas dominated in crude-oil degrading microflora. Though the removal efficiency was lower than free bacteria when the temperature was 15 °C, SA and PVA+SA immobilization improved the resistance to salinity. The composite crude-oil degrading microbiota in this study demonstrated a perspective potential for crude oil removal from surface water under high salinity and low temperature conditions.