Biodegradable polymers provide an opportunity to divert plastic waste from landfills, with composting as an alternative disposal route. However, some biodegradable polymers, such as poly (lactic acid) (PLA), do not biodegrade as fast as other organic wastes during composting, affecting their general acceptance in industrial composting facilities. Bioaugmentation, the addition of specific microbial strains, is a promising technique to accelerate the biodegradation of compostable plastics, so that they biodegrade in comparable time frames with other organic materials. In this study, we evaluated the effect of bioaugmentation on the biodegradation of PLA and PLA bio-nanocomposites (BNCs) in simulated composting conditions. PLA, PLA with 5% organo-modified montmorillonite (PLA-OMMT5), and PLA with 0.4% surfactant (PLA-QAC0.4) films were produced and fully characterized. PLA-degrading bacteria were isolated through an enrichment technique with PLA as the sole carbon source at 58 °C. Isolates were identified as Geobacillus using 16 S rRNA gene sequencing and the NCBI database, and further used to study the effect of bioaugmentation on the biodegradation rate of PLA and BNCs in solid environments. The biotic and abiotic degradation was assessed in compost, inoculated vermiculite, and uninoculated vermiculite at 58 °C by analysis of evolved CO₂ using an in-house built direct measurement respirometer. Size exclusion chromatography was also used to measure and to monitor the change in molecular weight of the film samples retrieved every week during the biodegradation test. The microbial attachment on the surface of PLA of the isolated microbial strain and other microorganisms present in the compost was evaluated by a biofilm forming assay in wells incubated at 58 °C. Bioaugmentation with Geobacillus increased the evolution of CO₂ and accelerated the biodegradation phase of PLA and BNCs when tested in compost and inoculated vermiculite with compost mixed culture. Bioaugmentation could commercially be used to accelerate the biodegradation of PLA in compost environments.

可生物降解的聚合物提供了将塑料废物从垃圾填埋场转移的机会，可将堆肥作为替代处置途径。但是，某些可生物降解的聚合物，例如聚乳酸（PLA），在堆肥过程中的降解速度不及其他有机废物，影响了它们在工业堆肥设施中的普遍接受度。生物强化，添加特定的微生物菌株，是加速可堆肥塑料生物降解的有前途的技术，因此它们可在与其他有机材料相当的时间范围内生物降解。在这项研究中，我们评估了生物强化对模拟堆肥条件下PLA和PLA生物纳米复合材料（BNC）生物降解的影响。PLA，含5％有机改性蒙脱土（PLA-OMMT5）的PLA和含0.4％表面活性剂（PLA-QAC0）的PLA。4）制作了胶片并进行了充分表征。在58°C下，通过以PLA为唯一碳源的富集技术分离了降解PLA的细菌。隔离株被标识为Geobacillus使用16 S rRNA基因测序和NCBI数据库，并进一步用于研究生物强化对固体环境中PLA和BNCs生物降解速率的影响。通过使用内置的直接测量呼吸计分析释放的CO _2，在58°C下对堆肥，接种ver石和未接种ver石中的生物和非生物降解进行了评估。尺寸排阻色谱法还用于测量和监测在生物降解测试期间每周回收的薄膜样品的分子量变化。通过生物膜形成测定法在58°C孵育的孔中评估了分离的微生物菌株和堆肥中存在的其他微生物在PLA表面的微生物附着情况。生物强化当在堆肥和混合堆肥中接种ver石进行测试时，地芽孢杆菌可增加CO _2的释放并加速PLA和BNC的生物降解阶段。生物强化可以商业化地用于加速堆肥环境中PLA的生物降解。