Zhang Yi, Tay Joo Hwa
Department of Environmental Science and Engineering, Fudan University, 220 Handan Road, Yangpu District, Shanghai, 200433, China.
Department of Civil Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada.
J Environ Manage. 2016 Mar 15;169:34-45. doi: 10.1016/j.jenvman.2015.12.021. Epub 2015 Dec 22.
Aerobic granule is a novel form of microbial aggregate capable of degrading toxic and recalcitrant substances. Aerobic granules have been formed on phenol as the growth substrate, and used to co-metabolically degrade trichloroethylene (TCE), a synthetic solvent not supporting aerobic microbial growth. Granule formation process, rate limiting factors and the comprehensive toxic effects of phenol and TCE had been systematically studied. To further explore their potential at the level of microbial population and functions, phenol degraders were isolated and purified from mature granules in this study. Phenol and TCE degradation kinetics of 15 strains were determined, together with their TCE transformation capacities and other physiological characteristics. Isolation in the presence of phenol and TCE exerted stress on microbial populations, but the procedure was able to preserve their diversity. Wide variation was found with the isolates' kinetic behaviors, with the parameters often spanning 3 orders of magnitude. Haldane kinetics described phenol degradation well, and the isolates exhibited actual maximum phenol-dependent oxygen utilization rates of 9-449 mg DO g DW(-1) h(-1), in phenol concentration range of 4.8-406 mg L(-1). Both Michaelis-Menten and Haldane types were observed for TCE transformation, with the actual maximum rate of 1.04-21.1 mg TCE g DW(-1) h(-1) occurring between TCE concentrations of 0.42-4.90 mg L(-1). The TCE transformation capacities and growth yields on phenol ranged from 20-115 mg TCE g DW(-1) and 0.46-1.22 g DW g phenol(-1), respectively, resulting in TCE transformation yields of 10-70 mg TCE g phenol(-1). Contact angles of the isolates were between 34° and 82°, suggesting both hydrophobic and hydrophilic cell surface. The diversity in the isolates is a great advantage, as it enables granules to be versatile and adaptive under different operational conditions.
好氧颗粒是一种新型的微生物聚集体，能够降解有毒和难降解物质。以苯酚作为生长底物已形成好氧颗粒，并用于共代谢降解三氯乙烯（TCE），三氯乙烯是一种不支持好氧微生物生长的合成溶剂。已系统研究了颗粒形成过程、限速因素以及苯酚和三氯乙烯的综合毒性效应。为了在微生物种群和功能水平上进一步探索它们的潜力，本研究从成熟颗粒中分离并纯化了苯酚降解菌。测定了15株菌株的苯酚和三氯乙烯降解动力学，以及它们的三氯乙烯转化能力和其他生理特性。在苯酚和三氯乙烯存在下进行分离对微生物种群施加了压力，但该程序能够保留它们的多样性。发现分离株的动力学行为存在很大差异，参数范围通常跨越3个数量级。Haldane动力学很好地描述了苯酚降解，在4.8 - 406 mg L(-1)的苯酚浓度范围内，分离株表现出实际最大苯酚依赖氧利用率为9 - 449 mg DO g DW(-1) h(-1)。三氯乙烯转化观察到米氏和Haldane两种类型，在0.42 - 4.90 mg L(-1)的三氯乙烯浓度之间实际最大速率为1.04 - 21.1 mg TCE g DW(-1) h(-1)。三氯乙烯转化能力和基于苯酚的生长产率分别为20 - 115 mg TCE g DW(-1)和0.46 - 1.22 g DW g苯酚(-1)，导致三氯乙烯转化产率为10 - 70 mg TCE g苯酚(-1)。分离株的接触角在34°至82°之间，表明细胞表面既有疏水性又有亲水性。分离株的多样性是一个很大的优势，因为它使颗粒在不同操作条件下具有多功能性和适应性。
