【目的】优化氯氰菊酯降解菌株的降解条件,并分析其降解产物,为氯氰菊酯残留生物修复提供依据。【方法】在自主筛选拟除虫菊酯农药高效降解真菌Cladosporium sp.HU(ITS序列分析GenBank登录号HQ693526)的基础上,采用高效液相色谱法(HPLC)测定其在不同条件下降解氯氰菊酯的能力,并采用Andrews方程对其降解过程进行拟合;利用气相色谱-质谱联用法(GC-MS)分析其降解产物。【结果】枝孢霉菌Hu能以氯氰菊酯为唯一碳源生长,在通气、接种量为0.4g-L1-、温度25-30℃、pH7.0-8.0和振荡速率120r/min条件下,培养4d对100mg-L-1氯氰菊酯降解率达到90%以上;其降解动力学参数为qax=1.2042d-1,Ks=35.2718mg·L-1,Ki;439.9948mg.L-1该菌株降解氯氰菊酯最佳的初始浓度为124.5769mg-L-1;该菌株通过水解和氧化作用降解氯氰菊酯产生口-羟基-3-苯氧基苯乙腈、间苯氧基苯甲醛、对苯氧基-2,2-二甲基苯丙酮和对苯氧基苯乙酮,并推测间苯氧基苯甲醛和a-羟基-3-苯氧基苯乙腈为其降解中间产物。【结论】枝孢霉菌HU能高效、快速降解氯氰菊酯,具有开发商品化拟虫菊酯农药降解菌剂或酶制剂的潜力。
[Objective] The objective of this study is to optimize the biodcgradation conditions and analyze the degradation products from cypermethrin degradation by Cladosporium sp. HU, and to provide a basis for bioremediation of cypermethrin- contaminated environment. [Method] Based on the screening of pyrethroid-degrading fungal strain, Cladosporium sp. HU (the accession number of ITS sequence analysis GenBank is HQ693526), the degradation abilities of the isolated strain under different conditions were determined with high performance liquid chromatography (HPLC). The Andrews equation was used to describe the degradation kinetics with different cypermethrin concentrations (50-500 mg.Ll). The products from cypermethrin degradation were analyzed by gas chromatopraphy-mass spectrometry (GC-MS). [Result] Cladosporium sp. HU utilized cypermethrin as the sole carbon for growth in the mineral salt medium (MSM). Under the conditions of aeration, inoculum amount 0.4 g'L-1, 25-30℃, pH 7.0-8.0, and shaking speed 120 r/rain, Cladosporium sp. HU degraded cypermethrin rapidly with a degradation rate up to 90% within 4 d. The kinetic parameters of qmax, K3 and Kiwere 1.2042 d-1, 35.2718 mg'Ll and 439.9948 mg.Ll, respectively. And the optimal concentration of initial cypermethrin was 124.5769 mg.L-1. Cladosporium sp. HU degraded eypermethrin by hydrolysis and oxidation tO produce a-hydroxy-3-phenoxy-benzeneacetonitrile, 3-phenoxybenzaldehyde, 4-phenoxyphenyl-2,2-dimethyl-propiophenone and 4-phenoxyacetophenone. 3-Phenoxybenzaldehyde and a-hydroxy-3-phenoxy- benzeneacetonitrile were the intermediates of cypermethrin degradation. [Conclusion] Cladosporium sp. HU participated inefficient and rapid degradation of cypermethrin, which would be in favor of fungal or enzymic preparation industrial production to deal with pyrethroid residues.