T2-2菌株对多菌灵的降解特性及生物修复试验

Characterization of a carbendazim-degrading Trichoderma sp. T2-2 and its application in bioremediation

摘要:

摘要：【目的】为获得降解多菌灵的微生物菌株，并用其制备生物修复剂，修复被污染的土壤。【方法】从耐药性木霉菌株诱变选育过程中,得到一株能降解多菌灵的变异菌株T2-2。该菌株在多菌灵浓度100 mg/L无机盐培养基中, 于25℃、200 r/min振荡培养取样，用HPLC-MS检测代谢产物；以玉米秸秆粉为原料经固体发酵制成T2-2生物修复剂；采用土壤人工接种,在T2-2菌剂接种量为107cfu/g干土、多菌灵含量为0.1 mg/g干土时进行灭菌土和自然土壤的修复试验；另外，还做了T2-2菌剂对黄瓜枯萎病的活体防效试验。【结果】处理2 d的培养液，HPLC-MS检测出代谢产物为：2-氨基苯并咪唑，苯并咪唑和2-氨基苯腈，处理5 d的培养液经检测未发现多菌灵和代谢产物；土壤修复试验中，灭菌土壤中的多菌灵接种6 d被完全降解，而自然土壤中的多菌灵被完全降解缩短到4 d。说明秸秆粉作为共代谢底物，促进了T2-2和土著微生物的共代谢降解作用；另外，T2-2菌剂对黄瓜枯萎病的活体防治效果达到81.7%，优于化学农药。【结论】木霉T2-2菌株即可降解土壤中的多菌灵，又可防治植物病害。

Abstract:

Abstract: [Objective] To obtain carbendazim-degrading microbial strains, and to use them for bioremediation of contaminated soil. [Methods] A carbendazim-degrading bacterium T2-2 was isolated from the screening of drug-tolerated mutants Trichoderma strains. High-pressure liquid chromatography-mass spectrometry (HPLC-MS) analysis showed the presence of the metabolites after shake incubation of the Trichoderma T2-2 at temperature 25℃, 200r/min in mineral salt medium that contained 100mg/L carbendazim. We prepared T2-2 bioremediation agents from crop straw through solid fermentation. By inoculating T2-2 in soil, we performed a bioremediation test of sterilized soil and original soil at 0.1mg/g dry soil of carbendazim concentration and 107cfu/g dry soil of inoculating amount. In addition, we also conducted a control effect experiment of T2-2 against fusarium wilt of cucumber. [Results] The metabolites detected by HPLC-MS were 2-aminobenzimidazole, benzimidazole, and 2-aminobenxinitrile in the culture filtrate after 2 days of incubation. Carbendazim and metabolites could no longer be detected through the High-pressure liquid chromatography (HPLC) analysis in the culture filtrate after 5 days of incubation. In the soil bioremediation test, carbendazim in the sterilized soil was degraded completely after 6 days of inoculation, whereas the process only needed 4 days in original soil. It showed crop straw could function as co-metabolic substrate and promote co-metabolism of T2-2 and indigenous microorganisms. Moreover, the efficiency of T2-2 against cucumber fusarium wilt might reach 81.7%, which is superior to chemical pesticide. [Conclusion] T2-2 could degrade carbendazim in soil and thus control plant disease.