Construction of diesel fuel-degrading bacterial consortium from coastal waters and its characteristics on degradation of diesel fuel

Abstract:

[Objective] For the purpose of control marine diesel pollution by biological treatment technology. [Methods] Diesel act as sole carbon source, using enrichment and screening methods to select diesel fuel-degrading bacteria from Shenzhen harbor area; bacterial consortium is constructed by mixing and orthogonal experiments; single-factor experimental is used to study the effect of environmental factors on diesel biodegradation by the consortium; using chromatography-flame ionization detection (GC-FID) to analyze the changes of diesel components before and after degradation, physiological, biochemical experiment and 16S rRNA gene sequence analysis are used to identify the strains. [Results] Sixteen diesel fuel-degrading bacteria were isolated and the highest degrading rates were up to 40.8% in 7 days. Bacteria consortium CQ1 was composed of C1-8, C2-10 and C3-13 strains, and the dosage was 0.5%, 2.0% and 1.0% respectively. Compared to the single strain, the degrading rate of CQ1 was increased by more than 10%. The best degrading effects would be up to 60% in 9 days under the optimum conditions that 30 °C, pH 7.6, shaking speed 220 r/min and diesel concentration 20 g/L. The result of GC-FID showed that most n-alkanes C11?C27 can be degraded by bacteria consortium CQ1 and the degradation rate of C21?C27 were up to 100%. In addition, the results showed that C1-8 belonged to Microbacterium sp., C2-10 belonged to Ensifer sp., C3-13 belonged to Corynebacterium variabile. [Conclusion] CQ1 has bright application prospects of bioremediation for offshore diesel pollution.

Key words:Diesel fuel-degrading bacteria, Bacteria consortium, Degradation rate, Environment factor, identification