Hydrocarbon-associated substrates reveal promising fungi for poly (ethylene terephthalate) (PET) depolymerization

Abstract

Recalcitrant characteristics and insolubility in water make the disposal of synthetic polymers a great environmental problem to be faced by modern society. Strategies towards the recycling of post-consumer polymers, like poly (ethylene terephthalate, PET) degradation/depolymerization have been studied but still need improvement. To contribute with this purpose, 100 fungal strains from hydrocarbon-associated environments were screened for lipase and esterase activities by plate assays and high-throughput screening (HTS), using short-and long-chain fluorogenic probes. Nine isolates were selected for their outstanding hydrolytic activity, comprising the genera Microsphaeropsis, Mucor, Trichoderma, Westerdykella, and Pycnidiophora. Two strains of Microsphaeropsis arundinis were able to convert 2-3% of PET nanoparticle into terephthalic acid, and when cultured with two kinds of commercial PET bottle fragments, they also promoted weight loss, surface and chemical changes, increased lipase and esterase activities, and led to PET depolymerization with release of terephthalic acid at concentrations above 20.0 ppm and other oligomers over 0.6 ppm. The results corroborate that hydrocarbon-associated areas are important source of microorganisms for application in environmental technologies, and the sources investigated revealed important strains with potential for PET depolymerization.

Improved Denitrification Performance of Polybutylene Succinate/Corncob Composite Carbon Source by Proper Pretreatment: Performance, Functional Genes and Microbial Community Structure

“…Trichoderma can generate abundant lignocellulolytic enzymes and have been deemed as efficient compost microbes [ 58 ]. A previous study showed that Westerdykella exhibit the ability to degrade refractory organic compounds such as poly-ethylene terephthalate and polycyclic aromatic hydrocarbons [ 59 ]. Considering the lowest DOC level in PC-OH-A ( Figure 1 c), the excessive pretreatment degree of plant materials led to a large loss of organic matter and a lack of carbon sources, which eventually resulted in the enrichment of Westerdykella that could degrade refractory organic matter.…”

Enzymes’ Power for Plastics Degradation

“…Additional pH variation by monitoring the reaction supernatant can also be instructive. 46 More specific to PLA, the total organic carbon (TOC) value can be used as an indicator of the content of the water-soluble PLA oligomers and monomer formed by hydrolysis. As a means to evaluate the hydrolysis of polyester films, optical waveguide light mode spectroscopy (OWLS) is based on sensing change in the refractive indices across the sensorsolution interfaces.…”

Occurrence, toxicity and remediation of polyethylene terephthalate plastics. A review

“…SEM shows the unevenness and cracks on Agripack and Carton pack PET (AP and CP-PET) surface treated with an enzyme TfCut2 from Thermobifida fusca (Wei et al 2019 ). The cracks and mycelial adherence were observed on the surface of PET after the fermentation with Microsphaeropsis arundinis (Malafatti-Picca et al 2019 ). SEM micrographs of PET provide insight into the cracks, stability of polymer and also information on the pollutants adsorbed onto their surface.…”