聚(己二酸丁二醇酯-共对苯二甲酸酯)(PBAT)是一种生物降解塑料,在中温和嗜热厌氧条件下都难以降解。在这项研究中,热碱预处理的影响(48小时,70°C,1%w/vNaOH)对PBAT的厌氧降解(AD),研究了聚乳酸(PLA)和PBAT/PLA共混塑料。在中温条件下,预处理仅提高了PBAT/PLA/淀粉塑料的甲烷产率(100天,51和34NmL/gVSadd对于处理过的和原始的塑料,分别)。在高温条件下,预处理提高了PLA的产甲烷率,PBAT和PBAT/PLA/淀粉塑料在开始阶段(22天,原始和处理过的PBAT为35和79NmL/gVSadd,分别),但在孵育结束时没有改变甲烷产量(100天,91NmL/gVSadd对于原始和处理过的PBAT)。分子量的降低和塑料表面上孔结构的形成加速了微生物对塑料的利用。此外,预处理的塑料倾向于形成尺寸主要低于500μm(>90%)的微塑料(MPs)。MP的数量随退化时间动态变化。几个属的细菌在嗜热条件下显示出生物降解塑料的特定降解,包括脱硫杆菌,Coprothermobacter,割菌,c_D8A-2和热丙酮。结果表明,热碱预处理引起的MPs问题应引起更多关注。
Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable plastic that is difficult to degrade under both mesophilic and thermophilic anaerobic conditions. In this study, the impact of the thermo-alkaline pretreatment (48 h, 70 °C, 1 % w/v NaOH) on the anaerobic degradation (AD) of PBAT, poly(lactic acid) (PLA) and PBAT/PLA blended plastics was investigated. Under mesophilic conditions, pretreatment only improved the methane yield of PBAT/PLA/starch plastic (100 days, 51 and 34 NmL/g VSadd for the treated and original plastics, respectively). Under thermophilic conditions, the pretreatment increased the methanogenic rate of PLA, PBAT and PBAT/PLA/starch plastic at the beginning stage (22 days, 35 and 79 NmL/g VSadd for original and treated PBAT, respectively), but did not change the methane yield at the end of the incubation (100 days, 91 NmL/g VSadd for original and treated PBAT). The reduction in the molecular weight and the formation of pore structures on the plastic surface accelerated the utilization of plastics by microorganisms. Furthermore, the pretreated plastics tend to form microplastics (MPs) with size predominantly below 500 µm (>90 %). The numbers of MPs dynamically changed with the degradation time. Several genera of bacteria showed specific degradation of biodegradable plastics under thermophilic conditions, including Desulfitibacter, Coprothermobacter, Tepidimicrobium, c_ D8A-2 and Thermacetogenium. The results suggest that more attention should be paid to the problem of MPs arising from the thermo-alkaline pretreatment.