白腐菌在固体培养基下对吲哚和吡啶的降解

Biodegradation of indole and pyridine by white rot fungi in rice straw

研究了稻草秆粉介质中白腐菌对吲哚和吡啶的降解。实验结果表明,质量浓度分别为200、80mg/L左右的吲哚可被白腐菌去除99%以上,质量浓度为74mg/L吡啶的去除率为61.5%;白腐菌在稻草秆粉培养体系中对吲哚和吡啶的降解,符合零级反应动力学,其中反应速率常数K(高浓度吲哚)>K(低浓度吲哚)>K(吡啶);高低浓度吲哚和吡啶3个降解体系的漆酶活力在第6天达到最大;漆酶在吲哚和吡啶降解过程中起着较重要的作用,但酶活的变化与吲哚和吡啶的相对去除率不呈线性相关,稻草秆粉培养基中的介质和培养环境在降解过程中可能也起着重要作用。

White rot fungus Pleurotus ostreatus is known to produce an enzyme capable of breaking down aromatic compounds. Experimental runs were performed to study biodegradation of indole and pyridine at 25℃ in small flasks, each containing 10 mL of white rot fungi culture, 10 mL of substrate solution and a small amount of solid medium of pulverized rice straw and others. Two sets of control samples were prepared in the same manner without the fungi or the solid medium. Comparative data demonstrated that the fungi and the solid medium were both essential for effective biodegradation. Under the same test conditions, indole was more biodegradable than pyridine; 99% of indole was removed from two solutions （initial concentrations = 200 and 80 rag/L） in 5 days, while 61.5% of pyridine was removed （initial concentration = 74 mg/L） in 15 days. The concentration decay data of degradation in three solutions were well represented by the zero order kinetics, and the order of the rate constant was Khigh concentration indole〉 Klow concentration indole〉Kpyridinc. The enzyme laccase produced in the three test systems was most active on the sixth day. The rice straw based solid medium and the growth environment also had important roles in the observed biodegradation of indole and pyridine.