嗜热脂肪地芽胞杆菌对聚苯乙烯的降解性能

微生物降解是废旧聚苯乙烯塑料（polystyrene，PS）最具持续性的处理方法.嗜热微生物具有较高的生物转化效率，可有效促进有机固废的降解，然而目前对嗜热微生物介导的PS塑料降解缺乏深入地研究.本文以堆肥中分离的1株嗜热脂肪地芽胞杆菌-FAFU011菌株（Geobacillus stearothermophilus FAFU011）为研究对象，分析其对PS的降解性能及机制.结果表明，FAFUA011可以将PS作为碳源进行生长，并在其表面形成稳定的生物膜；经过56 d的处理后，FAFUA011可使PS塑料膜的质量下降4.2%，重均分子质量和数均分子质量分别降低17.4%和18.2%；SEM分析表明，FAFUA011可造成PS表面产生侵蚀坑洞；XPS和接触角分析结果表明，经过FAFUA011的作用，增加了PS表面含氧结构的种类和数量，并改变了PS表面的亲水性能，从而有利于微生物在PS塑料表面的定殖，并进一步促进PS生物降解；基于2D-COS分析，确定了PS降解过程中官能团随时间变化的顺序为：1491 cm^-1（C—H） > 1450 cm^-1（C—H） > 1601 cm^-1（C=C） > 1027 cm^-1（C—O） > 1068 cm^-1（C=O） > 1366 cm^-1（C—OH）.本研究结果表明FAFU011能够促进PS塑料的嗜热生物氧化降解.

Biodegradation of Polystyrene by Geobacillus stearothermophilus

Biodegradation is the most sustainable treatment method for waste polystyrene (PS). Thermophiles possess highly efficient biotransformation capabilities that could enhance the biodegradation efficiency of organic solid wastes. However, detailed research on the degradation of PS plastics by thermophile is scarce. Here, the degradation performance of a strain of Geobacillus stearothermophilus FAFU011 (FAFUA011) isolated from compost was examined. The results showed that strain FAFUA011 could utilize PS as the sole carbon source for growth and formed a stable biofilm on the surface of PS fragments. During 56 days of degradation, FAFU0011 caused a total mass loss of PS of 4.2% and decrease in molecular weight of 17.4%-18.2%. Based on SEM observations, FAFUA011 causes erosion hollows on the surface of PS, thus increasing the type and number of oxygen-containing structures that alter its hydrophilic properties. These changes facilitate the colonization of other microorganisms and further promote biodegradation. Based on 2D-COS analysis, the chronological order of the change in functional groups during the degradation process were identified as follows:1491 cm^-1(C-H) > 1450 cm^-1(C-H) > 1601 cm^-1(C=C) > 1027 cm^-1(C-O) > 1068 cm^-1(C=O) > 1366 cm^-1(C-OH). Overall, these results reveal that FAFU011 could promote the thermophilic bio-oxidative degradation of PS plastic.