几株细菌对聚苯乙烯泡沫及聚乳酸的降解性能

Degradation of polystyrene foam and polylactic acid by several strains of bacteria

由于塑料的大量使用,并且大部分塑料在自然界中难以降解,使得塑料垃圾对环境造成了巨大的负面影响.本研究从黄粉虫肠道和土壤分离能降解聚苯乙烯泡沫及聚乳酸塑料的菌株.黄粉幼虫以6∶1的麸皮与塑料配比饲喂21 d,对其肠道菌株进行分离、培养.同时对混杂有破裂、发脆、老化塑料的土壤菌株进行分离、培养.而后利用扫描电镜切片观察和菌数量测定,筛选对聚苯乙烯泡沫及聚乳酸这两种塑料有降解特性的菌株.最后设计混菌体系,优化出最佳的降解组合.结果从黄粉虫肠道和土壤中分离筛选出5种降解效果好的菌株,分别为Klebsiellasp.G-1、 Klebsiella pneumoniaestrainPLA-2、Klebsiella pneumoniae subsp. N-2、Bacterium strain G-2和Escherichia coli strain L-1.并得到5个对聚苯乙烯泡沫降解性更好的混菌体系:A_(5)(Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、A_(10)(Escherichia coli strain L-1、Bacterium strain G-2)、B_(1)(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、 Klebsiella pneumoniae subsp. N-2)、 B_(2)(Klebsiella sp. G-1、 Klebsiella pneumoniae strain PLA-2、Escherichia coli strain L-1)和C_(4)(Klebsiella sp. G-1、 Klebsiella pneumoniae subsp. N-2、 Escherichia coli strain L-1、Bacterium strain G-2).研究结果表明,黄粉虫肠道及土壤环境中存在对聚苯乙烯泡沫及聚乳酸塑料有一定降解性的细菌,且混菌体系对聚苯乙烯泡沫的降解效果要优于单株菌.

Plastics were used in large quantities and difficult to degrade in nature, making plastic waste have a huge negative impact on the environment. Strains which can degrade polystyrene foam and polylactic acid plastics were isolated from tenebrio molitor gut and soil mixed with cracked,brittle and aged plastic. The tenebrio molitors were feed with bran and plastics at a ratio of 6∶1 for21 days and the gut bacteria were isolated and cultured. Plastic section and the cell concentration were used to investigate the characteristics of plastic degradation. Finally, the mixed bacteria system was designed to optimize the degradation. The results shown that five strains with good degradation effect were screened from the intestinal tract and soil, which were Klebsiella sp.G-1、 Klebsiella pneumoniae strain PLA-2、 Klebsiella pneumoniae subsp. N-2、 Bacterium strain G-2 and Escherichia coli strain L-1. Meanwhile, five mixed bacteria systems [A_(5)(Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、A_(10)(Escherichia coli strain L-1、Bacterium strain G-2)、B_(1)(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Klebsiella pneumoniae subsp. N-2)、B_(2)(Klebsiella sp. G-1、Klebsiella pneumoniae strain PLA-2、Escherichia coli strain L-1) and C_(4)(Klebsiella sp. G-1、Klebsiella pneumoniae subsp. N-2、Escherichia coli strain L-1、Bacterium strain G-2)] with good degradation effect were also obtained through mixing and matching. The results suggested that strains which can degrade polystyrene foam and polylactic acid plastics could been isolated from tenebrio molitor gut and soil, the degradation of polystyrene foam by mixed bacteria system was better than single bacteria.