Microbes and environment sustainability: An in-depth review on the role of insect gut microbiota in plastic biodegradation

Though several microorganisms degrade plastics in diverse ecosystems, the degradation rate is remarkably slow; however, this process can be accelerated comparatively within an insect host. Available information on the plastic degradation ability of insects and the mechanisms underlying this process is still limited; therefore, many questions about insect-mediated plastic degradation remain unanswered. Generally, the mandibulate insects transform plastics into subtle fragmented forms by their collective chewing actions after being ingested into the guts. The gut microorganisms convert plastic polymers into assimilable simpler forms through microbial enzymes. Insect ability to degrade plastic is widespread; some insects degrade specific types of plastic, while others can degrade multiple types. Therefore, insect species greatly vary according to the biodegradation processes and based on chemical orientation and structure of plastics. This review focuses on the diversity of insect fauna responsible for plastic degradation, the types of plastics degraded by insect species, and how the degradation mechanism occurs within their gut microbial environment. Since waste plastics are causing significant annoyance, this review will further discuss how insects can benefit waste management by degrading plastics without causing any environmental hazards.