混合白腐真菌的固定化及其在治理铅污染废水中的应用

Immobilization of mixed white rot fungi and it application in the treatment of lead-contaminated wastewater

摘要:

【目的】为缓解重金属废水污染对全球食品安全和人类健康的威胁，降低铅(plumbum, Pb)在土壤及动植物体内的积累，借助固定化技术提高菌株的重金属去除效率。【方法】以白腐真菌(white rot fungi)为实验材料，通过混菌兼容性及铅离子(Pb²⁺)去除能力筛选出吸附效果好且兼容性优的复合菌种，探究最优混菌类型及其比例，优化菌球最佳固定化助剂配方，在此基础上深入探究菌球在实际应用中的最优吸附条件。【结果】黄孢原毛平革菌(Phanerochaete chrysosporium)、云芝(Coriolus versicolor)、凤尾菇(Lentinus sajor-caju)和平菇(Pleurotus ostreatus) 4种菌株兼容效果佳，可进行后续实验；其中云芝和凤尾菇以体积1:1混合后对Pb²⁺去除效果显著优于各单菌作用；固定化条件优化实验中，20.0 g/L海藻酸钠、15.0 g/L生物炭和2.0×10⁶个/mL白腐真菌组成混菌体系，辅以二氧化硅及沸石制得的固定化菌球在96 h Pb²⁺去除率为90.63%，且制得的固定化菌球机械强度高，耐受机械剪切力强；环境条件优化实验中，固定化菌球投加量为8.35 g/L、pH 5.64时，96 h Pb²⁺去除率可达97.45%；本固定化菌球吸附-解吸-再吸附后可重复利用7次并保持高效Pb²⁺去除能力。【结论】固定化白腐真菌混合菌株相较传统的单菌处理方式能够显著提高微生物利用率及含铅废水处理效率，在适宜的条件下短时间内可极大程度吸附废水中的Pb²⁺，减轻重金属污染物造成的环境生态威胁，因此将固定化白腐真菌混合菌株应用于重金属废水修复领域对推进环境保护事业具有重要意义。

关键词:铅污染;白腐真菌;混菌固定化;胞外聚合物组分变化

Abstract:

[Objective] To mitigate the threat of heavy metal pollution in wastewater to global food safety and human health, reduce the accumulation of lead (Pb) in soil, plants, and animals, and improve the removal rate of heavy metals by immobilizing microbial strains. [Methods] We carried out mixed strain test to select the white rot fungal strains with strong Pb²⁺ removal effects and excellent compatibility and explored the optimal strains and ratio for combination. Furthermore, we optimized the formula of the fungal strain composite and explored the optimal adsorption conditions of the composite in application. [Results] Phanerochaete chrysosporium, Coriolus versicolor, Lentinus sajor-caju, and Pleurotus ostreatus with good compatibility were selected for subsequent experiments. C. versicolor mixed with L. sajor-caju at a volume ratio of 1:1 outperformed the single strains in removing Pb²⁺. The fungal strain composite composed of 20.0 g/L sodium alginate, 15.0 g/L biochar, 2.0×10₆ CFU/mL white rot fungi, silica, and zeolite showed the Pb²⁺ removal rate of 90.63% within 96 h. Moreover, this composite had higher mechanical strength and strong resistance to mechanical shear. At the addition amount of 8.35 g/L and pH 5.64, the composite demonstrated the Pb²⁺ removal rate of 97.45% within 96 h. Moreover, this composite can be reused 7 times after adsorption-desorption-readsorption and maintained high Pb²⁺ removal capacity. [Conclusion] The immobilized white rot fungal strain composite can significantly improve the microbial utilization rate and wastewater treatment efficiency compared with single strains. It can greatly adsorb Pb²⁺ in wastewater under appropriate conditions within a short time and reduce the environmental threat caused by heavy metal pollutants. Therefore, the promotion of environmental protection greatly benefits from the use of immobilized mixed white rot fungal strains in the treatment of heavy metal-contaminated wastewater.

Key words:lead pollution;white rot fungi;immobilization of mixed fungi;component variations of extracellular polymeric substances