Department of Civil Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India; Centre for Sustainable Polymers, Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
Centre for Sustainable Polymers, Institute of Technology Guwahati, Guwahati, 781039, Assam, India; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
Environ Pollut. 2024 Aug 15;355:124255. doi: 10.1016/j.envpol.2024.124255. Epub 2024 May 28.
Polylactic Acid (PLA) based compostable bioplastic films degrade under thermophilic composting conditions. The purpose of our study was to understand whether sample pre-treatment along with bioaugmentation of the degradation matrix could reduce the biodegradation time under a simulated composting environment. Sepcifically, we also explored whether the commercial composts could be replaced by landfill-mined soil-like fraction (LMSF) for the said application. The effect of pre-treatment on the material was analysed by tests like tensile strength analysis, hydrophobicity analysis, morphological analysis, thermal degradation profiling, etc. Subsequently, the degradation experiment was performed in a simulated composting environment following the ASTM D5338 standard, along with bioaugmentation in selected experimental setups. When the novel approach of material pre-treatment and bioaugmentation were applied in combination, the time necessary for 90% degradation was reduced by 27% using compost and by 23% using LMSF. Beyond the improvement in degradation rate, the water holding capacity increased significantly for the degradation matrices. With pH, C: N ratio and microbial diversity tested to be favourable through 16s metabarcoding studies, material pre-treatment and bioaugmentation allow LMSF to not only replace commercial compost in polymer degradation but also find immense application in the agricultural sector of drought-affected areas (for better water retention) after it has been used for PLA degradation.
聚乳酸（PLA）基可堆肥生物塑料薄膜在嗜热堆肥条件下降解。我们研究的目的是了解在模拟堆肥环境下，样品预处理和生物增强降解基质是否可以减少生物降解时间。具体来说，我们还探索了是否可以用垃圾填埋场挖掘的土壤样分数（LMSF）代替商业堆肥来进行所述应用。通过拉伸强度分析、疏水性分析、形态分析、热降解分析等测试来分析预处理对材料的影响。随后，根据 ASTM D5338 标准在模拟堆肥环境中进行降解实验，并在选定的实验装置中进行生物增强。当采用材料预处理和生物增强的新方法相结合时，使用堆肥和 LMSF 分别将 90%降解所需的时间缩短了 27%和 23%。除了提高降解速度外，降解基质的持水能力也显著提高。通过 16s 宏条形码研究测试了 pH 值、C：N 比和微生物多样性，发现材料预处理和生物增强不仅可以使 LMSF 在聚合物降解中替代商业堆肥，而且在 PLA 降解后，LMSF 还可以在受干旱影响地区的农业部门得到广泛应用（用于更好地保持水分）。
