一株地膜降解真菌的筛选及其降解性能分析

Screening of a plastic mulch film degrading fungus

摘要:

[目的]分离并鉴定具有聚乙烯材料降解能力的微生物菌株，探究其降解农用地膜的效能，为地膜的微生物降解途径提供支撑。[方法]以线性低密度聚乙烯粉末为唯一碳源的培养物中分离出1株具有降解聚乙烯材料能力的真菌，利用分子生物学方法结合菌株的培养性状对该菌株进行鉴定，通过观察聚乙烯粉末降解情况和测定地膜失重率，结合红外扫描、高分辨场发射扫描电子显微镜分析该菌株对农用地膜的降解效果。[结果]筛选获得1株具有农用地膜降解效果的真菌菌株PT1，经鉴定为桔青霉（Penicillium citrinum），桔青霉PT1菌株能以重均分子量（M_w）2000和400000的聚乙烯粉末作为唯一碳源生长，经红外扫描、电镜观察发现桔青霉PT1可侵蚀传统聚乙烯地膜。桔青霉PT1能快速利用聚酯类生物降解地膜生长，35 d地膜失重率达50%左右。[结论]本文筛选到具有地膜降解特性的桔青霉PT1真菌，丰富了降解聚乙烯材料的微生物类群，同时也为废弃农用地膜的处理提供了环保的处理途径。

Abstract:

[Objective] The aim of this study was to isolate microorganisms capable of degrading polyethylene materials, for example, agricultural mulch film. [Methods] By culturing the fungal strains with liner low-density polyethylene powder, we obtained a fugal strain with the ability of polyethylene degradation. Then we identified this strain by cultivation characters and molecular biology methods. Furthermore, we tested the degradation efficiency of agricultural mulch film of the fungus, weight loss of mulch, Fourier Transform infrared spectroscopy (FTIR) spectrogram and high-resolution field emission scanning electron microscope. [Results] Fungus PT1 capable of degrading agricultural mulch film was identified as Penicillium citrinum. PT1 could grow on linear low-density polyethylene powder with an average molecular weight of 2000 or 400000 as the sole carbon source. It could degrade low-density polyethylene powder and corrode traditional polyethylene film monitored by FTIR spectrogram and high-resolution field emission scanning electron microscope. The weight loss of polyester biodegradable film is about 50% after 35 days when co-cultured with PT1 strain. [Conclusion] A new fungus strain to degrade agricultural mulch film, P. citrinum PT1, was isolated and identified. Our finding provides a new friendly way to deal with agricultural mulch film.