Guidelines toward ecologically-informed bioprospecting for microbial plastic degradation

Abstract

Biological degradation of plastics by microbial enzymes offers a sustainable alternative to traditional waste management methods that often pollute the environment. This review explores ecologically-informed bioprospecting for microorganisms possessing enzymes suitable for biological plastic waste treatment. Natural habitats enriched in plastic-like polymers, such as insect-derived polyesters, epicuticular microbial biofilms in the phyllosphere of plants in extreme environments, or aquatic ecosystems, are highlighted as promising reservoirs for bioprospecting. Anthropogenic habitats, including plastic-polluted soils and the plastisphere, have yielded potent enzymes such as PETases and cutinases, which are being exploited in biotechnology. However, bioprospecting in plastispheres and artificial environments frequently leads to the isolation of environmental opportunistic microorganisms, such as Pseudomonas aeruginosa, Aspergillus fumigatus, Parengyodontium album, or species of Fusarium, which are capable of becoming human and/or plant pathogens. These cases necessitate stringent biosecurity measures, including accurate molecular identification, ecological assessment, and containment protocols. Beyond advancing bioprospecting approaches toward a broader scope of relevant habitats, this review underscores the educational value of such screenings, specifically, in understudied natural habitats, emphasizing its potential to uncover novel enzymes and microorganisms and engage the next generation of researchers in interdisciplinary study integrating environmental microbiology, molecular biology, enzymology, polymer chemistry, and bioinformatics. Finally, we offer guidelines for microbial bioprospecting in various laboratory settings, ranging from standard environmental microbiology facilities to high-biosecurity facilities, thereby maximizing the diversity of scientists who may contribute to addressing urgent environmental challenges associated with plastic waste.

Keywords: Apis; Biosafety; Cuticle; Cutin; DNA barcoding; Enzyme engineering; Epicuticular biofilm; Parengyodontium album; Phyllosphere; Plastisphere.