Institute of Marine Biology and Pharmacology, Ocean College, Zhejiang University, Zhoushan, 316021, Zhejiang, China.
College of Environmental Science and Engineering, Guilin University of Technology, Guilin, 541006, China.
Environ Pollut. 2023 Oct 15;335:122365. doi: 10.1016/j.envpol.2023.122365. Epub 2023 Aug 10.
The widespread exploration and exploitation of crude oil has increased the prevalence of petroleum hydrocarbon pollution in the marine and coastal environment. Bioremediation of petroleum hydrocarbons using cell immobilization techniques is gaining increasing attention. In this study, the crude oil degradation performance of bacterial and fungal co-culture was optimized by entrapping both cells in sodium-alginate and polyvinyl alcohol composite beads. Results indicate that fungal cells remained active after entrapment and throughout the experiment, while bacterial cells were non-viable at the end of the experimental period in treatments with the bacterial-fungal ratio of 1:2. A remarkable decrease in surface tension from 72 mN/m to 36.51 mN/m was achieved in treatments with the bacterial-fungal ratio of 3:1. This resulted in a significant (P < 0.05) total petroleum hydrocarbon (TPH) removal rate of 89.4%, and the highest degradation of n-alkanes fractions (from 2129.01 mg/L to 118.53 mg/L), compared to the other treatments. Whereas PAHs removal was highest in treatments with the most fungal abundance (from 980.96 μg/L to 177.3 μg/L). Furthermore, enzymes analysis test revealed that catalase had the most effect on microbial degradation of the target substrate, while protease had no significant impact on the degradation process. High expression of almA and PAH-RHDa genes was achieved in the co-culture treatments, which correlated significantly (P < 0.05) with n-alkanes and PAHs removal, respectively. These results indicate that the application of immobilized bacterial and fungal cells in defined co-culture systems is an effective strategy for enhanced biodegradation of petroleum hydrocarbons in aqueous systems.
原油的广泛勘探和开采增加了海洋和沿海环境中石油烃污染的普遍性。利用细胞固定化技术对石油烃进行生物修复越来越受到关注。在这项研究中，通过将细菌和真菌细胞分别包埋在海藻酸钠和聚乙烯醇复合珠粒中，优化了细菌和真菌共培养物对原油的降解性能。结果表明，真菌细胞在包埋后和整个实验过程中保持活性，而在细菌-真菌比例为 1:2 的处理中，细菌细胞在实验结束时已失去活力。在细菌-真菌比例为 3:1 的处理中，表面张力从 72 mN/m 显著下降到 36.51 mN/m，这导致总石油烃（TPH）的去除率达到了 89.4%，并且与其他处理相比，烷烃分数的降解程度最高（从 2129.01 mg/L 降至 118.53 mg/L）。相比之下，在真菌丰度最高的处理中，多环芳烃（PAHs）的去除率最高（从 980.96μg/L 降至 177.3μg/L）。此外，酶分析测试表明，过氧化氢酶对目标底物的微生物降解影响最大，而蛋白酶对降解过程没有显著影响。共培养物处理中 almA 和 PAH-RHDa 基因的高表达与烷烃和 PAHs 的去除分别显著相关（P<0.05）。这些结果表明，固定化细菌和真菌细胞在特定共培养系统中的应用是增强水相中石油烃生物降解的有效策略。
