Biodegradation and Mineralization of Polystyrene by Plastic-Eating Mealworms: Part 2. Role of Gut Microorganisms

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• 作者：Yu Yang ; Jun Yang ; Wei-Min Wu ; Jiao Zhao ; Yiling Song ; Longcheng Gao ; Ruifu Yang ; Lei Jiang
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：October 20, 2015
• 年：2015
• 卷：49
• 期：20
• 页码：12087-12093
• 全文大小：385K
• ISSN：1520-5851

文摘

The role of gut bacteria of mealworms (the larvae of Tenebrio molitor Linnaeus) in polystyrene (PS) degradation was investigated. Gentamicin was the most effective inhibitor of gut bacteria among six antibiotics tested. Gut bacterial activities were essentially suppressed by feeding gentamicin food (30 mg/g) for 10 days. Gentamicin-feeding mealworms lost the ability to depolymerize PS and mineralize PS into CO₂, as determined by characterizing worm fecula and feeding with ¹³C-labeled PS. A PS-degrading bacterial strain was isolated from the guts of the mealworms, Exiguobacterium sp. strain YT2, which could form biofilm on PS film over a 28 day incubation period and made obvious pits and cavities (0.2鈥?.3 mm in width) on PS film surfaces associated with decreases in hydrophobicity and the formation of C鈥揙 polar groups. A suspension culture of strain YT2 (10⁸ cells/mL) was able to degrade 7.4 卤 0.4% of the PS pieces (2500 mg/L) over a 60 day incubation period. The molecular weight of the residual PS pieces was lower, and the release of water-soluble daughter products was detected. The results indicated the essential role of gut bacteria in PS biodegradation and mineralization, confirmed the presence of PS-degrading gut bacteria, and demonstrated the biodegradation of PS by mealworms.