Amendment with compost-based matrix produced as a byproduct of PLA bioplastic degradation does not adversely impact the soil geoenvironment

The fate of the degradation matrices after bioplastic degradation is in the soil as a conditioner or biofertilizer. Holistic knowledge of their impact on soil application is unknown. This study explores the impact of compost/landfill-mined soil-like fractions (LMSF) amendment on the soil after being used for Polylactic Acid (PLA) degradation. Upon application, the Water Holding Capacity of the soil increased to 70% with compost and up to 41% with LMSF. When the changes in microbial diversity were studied with and without induced drought, critical variations were observed for the different genera controlling soil functions. Drought increased the diversity of the bacterial population in the soil, while the addition of the matrices after bioplastic degradation made the soil bacteria more resilient to drought stress. The micro- and macro-element profile of the soil was found to be conducive to agricultural applications. Using the degradation matrices as soil amendments may pose a risk of microbioplastic contamination. The remediation could necessitate bioaugmentation with bioengineered enzymes for which the scientific community should be well-versed in the structure and functional intricacies of the native enzymes. The study made a maiden attempt to analyse the structure of a PLA depolymerase enzyme from soil bacteria Amycolatopsis sp. and its binding interactions with PLA residues, using computational methods. Overall, the findings establish the scope for using bioplastic compost as an agricultural soil amendment within a circular economy, thereby promoting drought-resistant, sustainable agricultural practices, especially as climate change-induced weather alterations pose serious questions for global food security.