一株有色金属矿山1-亚硝基-2-萘酚降解菌的筛选、鉴定和降解特性

Isolation, identification, and degradation characteristics of a 1-nitroso-2-naphthol-degrading strain derived from nonferrous metal (loid) tailings

摘要:

1-亚硝基-2-萘酚是一类有色选矿药剂代表性的新型浮选药剂，在采选冶行业为了提高低品位矿物资源的利用率，被大量投入使用，该药剂的高稳定性进一步增大了矿山环境中重金属与有机选冶药剂复合污染的治理难度。微生物修复作为稠环芳烃(polycyclic aromatic hydrocarbons，PAHs)类污染物重要技术手段之一，具有安全、经济、高效和无二次污染等特点。【目的】本研究从我国广西河池市周边的典型有色金属尾矿环境中分离出1株高效降解1-亚硝基-2-萘酚的菌株，并分析其降解特性及其潜在的代谢途径，从而探究矿山复合污染生态系统中稠环芳烃类污染物的微生物修复技术的应用前景。【方法】从有色金属尾矿样本中筛选到以1-亚硝基-2-萘酚为唯一碳源的菌株，经16S rRNA基因序列鉴定，结合气相色谱-质谱联合(gas chromatography-mass spectrometer，GC-MS)检测分析菌株对1-亚硝基-2-萘酚的降解特性及中间代谢产物，并推测可能的代谢途径。【结果】筛选获得1株高效降解1-亚硝基-2-萘酚的Pseudomonas putida CUGB-JL11菌株，经鉴定为革兰氏阴性杆的恶臭假单胞菌。该菌株最适温度为30 ℃左右，最适pH值范围为6-8条件下，菌株5 d内对40 mg/L 1-亚硝基-2-萘酚的降解率高达81%。降解中间代谢产物主要为苯环类物质：苯甲羟肟酸甲酯和苯丙胺，但其母体及大部分中间产物都降解为小分子物质或者被完全降解。【结论】恶臭假单胞菌P. putida CUGB-JL11具有良好的1-亚硝基-2-萘酚降解能力和较强的环境适应性，有进一步被开发为微生物菌剂以用于稠环芳烃类污染修复的巨大潜力，为有色金属矿山生态系统中重金属和有机选冶药剂复合污染的微生物修复研究提供了理论依据和可利用的微生物资源。

关键词:有色金属选冶渣场;1-亚硝基-2-萘酚降解菌;分子鉴定;气相色谱-质谱(GC-MS)

Abstract:

As a new representative flotation reagent, 1-nitroso-2-naphthol is widely used in the mining and metallurgical industry to improve the utilization rate of low-grade mineral resources. It is highly stable, posing a challenge to the treatment of heavy metal pollution and organic smelting agent pollution in mine. Among the crucial techniques for the remediation of polycyclic aromatic hydrocarbons (PAHs), bio-remediation is safe and efficient with low cost and no secondary pollution. [Objective] To screen an efficient 1-nitroso-2-naphthol-degrading strain from the typical non-ferrous metal tailings in the periphery of Hechi city, Guangxi Zhuang autonomous region in China, analyze the degradation characteristics and potential metabolic pathways, and thereby examine the conditions for the microbial remediation of the mine polluted by compound pollutants including PAHs. [Methods] The strain which used 1-nitroso-2-naphthol as the only carbon source was screened and identified by 16S rRNA gene sequencing. Gas chromatography-mass spectrometry (GC-MS) was employed to analyze degradation characteristics of 1-nitroso-2-naphthol and the intermediate metabolites, and the metabolic pathways were predicted. [Results] An efficient strain was screened out and identified as the Gram-negative Pseudomonas putida CUGB-JL11. Under the optimal conditions of 30 ℃ and pH 6-8, the 5-day degradation rate of 40 mg/L 1-nitroso-2-naphthol by the strain was up to 81%. The main intermediate metabolites were the benzodiazepines methyl N-hydroxybenzenecarboximidoate and amphetamine, but the organic substances and most of the intermediates were degraded into small molecules or completely degraded. [Conclusion] CUGB-JL11 boasts high 1-nitroso-2-naphthol-degrading efficiency and strong environmental adaptability. It has a huge potential for the treatment of PAHs. This study lays a theoretical basis and provides microbial resources for bioremediation of nonferrous metal mine polluted by both heavy metals and flotation reagents.

Key words:nonferrous metal(loid) tailings;1-nitroso-2-naphthol-degrading bacterium;molecular identification;gas chromatography-mass spectrometry (GC-MS)