一株高氯酸盐还原细菌的分离鉴定与代谢特性

Isolation, identification and characterization of a perchlorate-reducing bacterium

摘要:

【背景】高氯酸盐是新型的水体污染物，利用微生物对含高氯酸盐的工业废液进行无害化处理具有高效、经济和环境友好性的特点。【目的】挖掘生长速度快、活性强、还原效率高的本土高氯酸盐还原细菌资源。【方法】从活性污泥中分离筛选高氯酸盐还原细菌，使用分子生物学技术对其进行种属鉴定，并通过微生物培养实验探究分离菌株的生理代谢特性。【结果】最终分离得到一株高氯酸盐还原细菌QD19-16，经过16S rRNA基因分析鉴定其属于布鲁氏杆菌(Brucella sp.)。菌株QD19-16属于兼性厌氧菌，最适生长温度为30 ℃，最适pH 7.0。菌株QD19-16是异养微生物，表现出多样的代谢能力，可以利用多种电子供体，如乙酸盐、酵母提取物和乳酸等，能够利用的电子受体包括硝酸盐、高氯酸盐、氯酸盐、硫酸盐和氧气等。在厌氧条件下，以高氯酸盐作为电子受体生长时，菌株QD19-16的最大比生长速率(μ_max)为0.279 d⁻¹，对高氯酸盐的半饱和常数(K_s)为0.294 mmol/L。【结论】菌株QD19-16是布鲁氏菌属中第一株被发现的高氯酸盐还原菌，扩大了变形菌门(Proteobacteria)中高氯酸盐还原菌的分布，能够应用于厌氧生物反应器中高氯酸盐还原微生物菌群的构建。

关键词:高氯酸盐;布鲁氏杆菌;代谢特性;电子受体;生物还原

Abstract:

[Background] Perchlorate is a new water pollutant, and using microorganisms for harmless treatment of industrial wastewater containing perchlorate has high efficiency, low costs, and environmental friendliness. [Objective] However, the resources of local perchlorate- reducing bacteria with fast growth, strong activity, and high reduction efficiency are extremely scarce and urgently need to be explored. [Methods] In this study, we isolated and screened perchlorate-reducing bacteria from activated sludge, identified their species using molecular biology techniques, and explored the physiological and metabolic characteristics of the isolated strains through microbial culture experiments. [Results] Finally, a perchlorate-reducing bacterial strain QD19-16 was isolated and identified as Brucella sp. by 16S rRNA gene analysis. Strain QD19-16 was an anaerobic facultative bacterium, with optimal growth at 30 ℃ and pH 7.0. Strain QD19-16 demonstrated a variety of metabolic activities and showed the ability to use acetate, yeast extract, and lactic acid as electron donors and perchlorate, chlorate, sulfate, and oxygen as electron acceptors. Under anaerobic conditions, the maximum specific growth rate (μ_max) of strain QD19-16 using perchlorate as an electron acceptor was 0.279 d⁻¹, with a half-saturation constant (K_s) of 0.294 mmol/L for perchlorate. [Conclusion] Brucella sp. QD19-16 is the first reported perchlorate-reducing bacterium of Brucella, expanding the distribution of perchlorate-reducing bacteria of Proteobacteria. Strain QD19-16 can be applied in assembling the microbial communities for perchlorate reduction in anaerobic bioreactors.

Key words:perchlorate;Brucella sp.;metabolic characteristics;electron acceptor;bioreduction