Predicting the plastic biodegradation potential within microbial lineages and across global ecosystems

Seeking soil microbial degraders and enzymatic genes for efficient biomass recycling.

Enzymatic degradation of plastic and optimization of microbial system for the production of its degrading enzymes

This study outlines existing metabolic engineering techniques for bio-upcycling PET into high-value compounds, as well as a number of engineering approaches intended to improve the performance of PET-degrading enzymes. One of the most popular aromatic polyesters in the world, polyethylene terephthalate (PET) has an annual demand of over 29 million metric tons in 2022 and is expected to rise by 40% by 2030. Due to the growing amount of PET waste and the existing insufficiency of recycling techniques, it has accumulated in terrestrial ecosystems, posing serious hazards to world health. These technologies seek to convert recovered PET into more valuable items in order to address energy issues as well as environmental sustainability. One potentially biosustainable technique for handling and recycling plastics is enzyme-mediated biocatalytic depolymerization. Protein engineering developments have been applied to modify and improve the many plastic-degrading enzymes that have been discovered from microbial sources. Additionally, microbial metabolic engineering makes it possible to create customized microbial chassis that can break down PET substrates and transform the resulting monomers into compounds that are useful for industry.

Emerging and Re-Emerging Challenges in Microbial Plastic Degradation and Prospects: A Review

This review aims to synthesize knowledge on plastics and microbial plastic degradation, with particular focus on emerging and re-emerging challenges that hinder its large-scale application.

Identification of soil microbes associated with real-time plastic degradation using in situ conductivity sensors

Microbial-mediated plastic degradation has the potential to address the persistent global problems of plastic waste and pollution. Previous work has shown that soils can harbour microbes capable of plastic degradation, but we expect there is a broader diversity of soil microbes capable of metabolizing plastics than identified to date using more traditional cultivation-based screening methods. Here we demonstrate a novel approach to identify putative plastic degrading microbes in soil. We paired in situ, real-time measurements of microbial plastic degradation on conductive sensors with subsequent microbial community profiling of the sensor-associated biofilms exhibiting appreciable degradation. To illustrate the utility of our approach, we focus on microbial degradation of the bioplastic polymer PHBV, poly(3-hydroxybutuyrate-co-3-hydroxyvalerate). We screened a range of soils with the in situ sensors to identify a subset of five soils with high PHBV degradation rates, and confirmed that PHBV degradation was due to microbial activity. We then extracted DNA directly from sensors placed in soils with high measured rates of PHBV degradation and used marker gene sequencing to identify the bacterial and fungal taxa associated with the observed PHBV degradation. We confirmed via in vitro culturing that microbes isolated from the sensors have a demonstrated capacity for PHBV metabolism. Together, these results highlight the benefit and feasibility of using low-cost, in-soil sensors to simultaneously collect real-time data on plastic degradation rates in soil and identify previously unrecognized microbial taxa capable of degrading and metabolizing plastic polymers in situ.

Isolation and mechanistic study of novel PLA-degrading bacteria from plastic manufacturing soil.

Petroleum-derived plastic pollution has become increasingly severe, stimulating the application demand for biodegradable polylactic acid (PLA). Nevertheless, the slow natural degradation rate of PLA limits its large-scale practical application. In this study, two potential novel strains with PLLA-degrading capacity, Chryseobacterium sp. L42 and Pedobacter sp. D55, were successfully isolated based on microbial community analysis of soil from plastic-manufacturing plants, combined with transparent-circle assays and PLA-film degradation tests. Integrated transcriptomic analysis and RT-qPCR validation, together with functional verification via heterologous expression in E. coli BL21 (DE3), confirmed that enzymes 10_101 and 10_105 from strain L42 exhibit prominent PLA-degrading activity, and both possess dual esterase and protease activities. Results from AlphaFold3 protein-structure prediction and molecular docking revealed that these functional enzymes contain conserved active pockets of PHA depolymerase, which target the ester bonds of PLA trimers through hydrogen bonds and hydrophobic interactions. This study clarifies the multi-enzyme synergistic PLA-degradation pathway mediated by strain L42. It provides valuable novel bacterial strains and degrading enzymes for the efficient bioremediation of plastic waste, and offers theoretical basis and practical reference for overcoming the technical bottlenecks in PLA degradation.

The Molecular Identification of Bacteria in Plastic Waste at the Pasir Bajing Garut Landfill

Plastic waste remains a major environmental concern worldwide. Approximately 418,262 tons of plastic waste, accounting for 20% of the total waste accumulation, are deposited annually at the Pasir Bajing Landfill (TPA) in Garut, Indonesia. Under these conditions, plastic serves both as a selective substrate for certain microorganisms and as a potential carbon source. This study aimed to identify bacteria associated with plastic waste at the Pasir Bajing Landfill using molecular techniques. Polystyrene waste samples were collected from three different sampling sites within the landfill area. Phylogenetic analysis based on 16S rRNA gene sequences revealed three bacterial isolates: isolate 2 was identified as Acinetobacter baumannii, isolate 5 as Atlantibacter hermannii, and isolate 6 as a member of the family Enterobacteriaceae. These isolates belong to the phylum Proteobacteria and may possess the potential to degrade plastic materials. Further studies are required to evaluate their plastic-degrading capabilities and to elucidate the metabolic pathways involved in the biodegradation process.