茅草菇菌丝球对铬黑T的脱色降解性能及毒性评价

Decolorization and degradation of Eriochrome Black T by mycelial pellets of Lactarius deliciosus and toxicity evaluation

摘要:

【目的】利用真菌茅草菇菌丝球对染料铬黑T (EBT)进行脱色和降解,探究在不同环境条件下对染料脱色性能的影响及作用机制。【方法】采用单因素分析探究真菌的最佳脱色能力,分光光度法测定真菌酶活,小麦种子萌发、大肠杆菌接触抑制试验及秀丽隐杆线虫毒性试验测定脱色前后废水的毒性。【结果】茅草菇菌丝球受摇床温度和转速影响较小,在pH 5、28℃、120 r/min下,400 mg/L的EBT溶液脱色率为97.14%。研究表明,茅草菇菌丝球在脱色过程中主要分泌3种木质素酶,即木质素过氧化物酶、锰过氧化物酶和漆酶,其最大酶活分别为(134.15±9.93)、(64.1±2.98)和(12.43±0.34) U/L。推断了染料降解的潜在路径,证实EBT的去除是通过生物吸附与降解的协同作用实现的。最后对脱色后的染料废水进行了多级毒性评价,包括植物毒性、微生物毒性和动物毒性,结果表明,脱色后的染料废水毒性显著降低。【结论】该研究对探讨生物法处理工业染料废水具有重要参考价值。

关键词:真菌发酵;染料脱色;木质素酶;毒性评价

Abstract:

[Objective] The mycelial pellets of Lactarius deliciosus were used to decolorize and degrade the dye Eriochrome Black T (EBT).We investigated the performance and mechanism of the decolorization by the mycelial pellets under different environmental conditions.[Methods] Single factor experiments were conducted to explore the optimal decolorization performance of the fungi.We measured the fungal enzyme activity by spectrophotometry,and performed wheat seed germination test,E. coli contact toxicity test,and Caenorhabditis elegans toxicity test to evaluate the toxicity of the EBT solutions before and after decolorization.[Results] The results manifested that the mycelial pellets of L. deliciosus were slightly affected by the shaker temperature and rotation speed.At pH 5,28℃,and 120 r/min,the decolorization rate for 400 mg/L EBT solution was 97.14%.In the decolorization process,the mycelial pellets of L. deliciosus secreted three ligninases,namely lignin peroxidase,manganese peroxidase,and laccase,which had the maximum activities of (134.15±9.93),(64.1±2.98),and (12.43±0.34) U/L,respectively.We deduced that the mycelial pellets of L. deliciosus removed EBT by the synergistic effects of biosorption and degradation.The multi-level toxicity evaluation demonstrated that the dye wastewater after decolorization had significantly reduced toxicity.[Conclusion] All these results have an important reference value in exploring the process of dye wastewater treatment with biological method.

Key words:fungal fermentation;dye decolorization;ligninase;toxicity evaluation