Screening for potent Polyethylene terephthalate (PET) degrading fungi: optimization of lipase production media and assessment of PET fabric waste degradation

Isolation of Marine-Derived Microorganisms for PET Biodegradation

This study isolated 305 marine-derived microorganisms with potential PET-degrading capability from samples collected from mangrove areas of Zhanjiang and the intertidal zones of Daya Bay, Shenzhen, China, using PET powder as a major carbon source and reveals the genetic basis underlying PET degradation and associated metabolic pathways in strain SCSIO 85700.

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.

Isolation, Screening and Characterization of Cellulolytic Fungi from Decaying Plant Materials for Sustainable Bioethanol Production

The increasing generation of plant waste presents significant environmental and public health challenges while simultaneously offering an abundant renewable resource for biofuel production. Microbial cellulases play a pivotal role in the conversion of lignocellulosic biomass into fermentable sugars, making the isolation of efficient cellulolytic fungi essential for sustainable bioethanol production. This study investigated the occurrence, isolation, screening, and characterization of cellulolytic fungi from decaying plant debris with the aim of identifying promising cellulase-producing strains for bioethanol production. Decaying plant debris samples were collected from domestic sources, processed under aseptic conditions, and cultured using standard microbiological techniques. Distinct fungal isolates were purified and identified based on their morphological and cultural characteristics. Preliminary screening for cellulase production was carried out on carboxymethyl cellulose (CMC) agar using Congo red staining, followed by quantitative determination of cellulase activity using standard enzyme assays. The cellulolytic potential of the isolates was evaluated by measuring hydrolysis zones and enzyme activity under controlled laboratory conditions. Selected isolates exhibiting superior cellulolytic activity were further characterized for their suitability in lignocellulosic biomass degradation. The findings demonstrated considerable diversity among the isolated microorganisms, with several fungal species exhibiting significant cellulolytic capabilities. The best-performing isolates producing large hydrolysis zones and high cellulase activities were Phanerochaete concrescens and Fusarium solani, producing 12.5 and 2.6 µmol/min/mg respectively indicating their potential application in enzymatic saccharification of decaying plant material. These findings provide valuable insights into the utilization of locally available microbial resources for sustainable waste valorization and renewable energy generation.

Screening and Fermentation Parameter Optimization of Lipase-Producing Trichosporon asahii

Waste cooking oil is generated in large quantities during food-waste processing, and its complex composition may pose environmental and public-health risks if it is improperly managed. Lipase-mediated conversion of waste cooking oil into biodiesel offers a promising strategy for both waste-oil valorization and greener fuel production. To expand the available microbial sources of lipases, this study isolated a strain with strong lipase-producing capacity from composted food-waste samples. The isolate was identified using molecular biological methods, the enzymatic properties of the extracellular lipase were characterized, and fermentation conditions for enzyme production were optimized by response surface methodology. The strain was identified as Trichosporon asahii. The lipase showed optimal catalytic activity at 40 °C and pH 8.0. Na+ and K+ enhanced lipase activity, whereas Ca2+, Mg2+, Mn2+, and Fe3+ inhibited the enzyme. Response surface optimization showed that a maximum lipase activity of 70.816 U/mL was obtained at a fermentation temperature of 31 °C, an initial pH of 6.33, an inoculum size of 6.843%, and a fermentation time of 120 h, representing an approximately 10-fold increase compared with the non-optimized condition. These findings provide a useful basis for developing food-waste-derived oils as biodiesel feedstocks through lipase-based fermentation and support the resource-oriented utilization of food waste.

Fungal consortium–driven valorization of agro-waste for sustainable co-production of industrial enzymes through integrated statistical bioprocess modelling

Enhanced degradation of polyethylene terephthalate by a two-strain microbial consortium.

Overall, ZY1 and G1B exhibited overlapping functions with relative functional differences and potential complementarity, supporting the use of synthetic microbial consortia to enhance PET depolymerization and downstream product conversion.