There has been a growing interest in poly(ethylene terephthalate) PET degradation studies in the last few years due to its widespread use and large-scale plastic waste accumulation in the environment. One of the most promising enzymatic methods in the context of PET degradation is the use of PETase from Ideonella sakaiensis, which has been reported to be an efficient enzyme for hydrolysing ester bonds in PET. In our study, we expressed a codon-optimized PETase gene in the yeast Yarrowia lipolytica. The obtained strain was tested for its ability to degrade PET directly in culture, and a screening of different supplements that might raise the level of PET hydrolysis was performed. We also carried out long-term cultures with PET film, the surface of which was examined by scanning electron microscopy. The efficiency of PET degradation was tested based on the concentration of degradation products released, and the results showed that supplementation of the culture with olive oil resulted in 66 % higher release of terephthalic acid into the medium compared to the mutant culture without supplementation. The results indicate the possibility of ethylene glycol uptake by both strains, and, additionally, the PETase produced by the newly engineered strain hydrolyses MHET. The structure of the PET film after culture with the modified strain, meanwhile, had numerous surface defects, cracks, and deformations.

Environmental concerns about the widespread use of non-biodegradable plastic have generated interest in developing quick and effective methods to degrade synthetic polymers. With millions of tons of plastic waste generated annually, biodegradation by microorganisms presents a promising and eco-friendly solution. However, a bottleneck has arisen due to the lack of standardized methods for verification of the biodegradation process. Based on this literature review, he techniques most commonly employed for this purpose currently include measuring mass loss, examining the surface of plastic fragments by scanning electron microscopy (SEM) and atomic force microscopy (AFM), and using analytical methods such as Fourier transform infrared spectroscopy (FTIR), pyrolysis–gas chromatography–mass spectrometry (Pyr-GC/MS) or high-performance liquid chromatography (HPLC). Each of these methods has its advantages and disadvantages. Nevertheless, currently, there is no universal approach to accurately assess the ability of individual microorganisms to degrade plastics. In this review, we summarize the latest advances in techniques for detecting biodegradation of synthetic polymers and future directions in the development of sustainable strategies for mitigating plastic pollution.

Hydrothermal carbonization (HTC) efficiently converts food waste into hydrochar for energy, soil improvement, and environmental remediation. However, optimizing HTC is challenging due to the complex interactions of temperature, residence time, moisture content, and catalyst dosage. This study explores the application of machine learning (ML) techniques for predicting and optimizing hydrochar yield and properties from the HTC of food waste. Key process parameters-temperature (120-360 °C), catalyst dosage (0-2 g), residence time (30-270 min), and moisture content were analyzed using three ML models: XGBoost (XGB), Support Vector Regression (SVR), and Linear Regression (LR). Among them, XGBoost demonstrated the highest predictive accuracy (R² = 0.87, MAE = 0.81, RMSE = 1.02), outperforming SVR (R² = 0.9386, MAE = 3.08) and LR (R² = 0.85, MAE = 0.86). Temperature was identified as the most significant factor (importance score = 0.91), followed by catalyst dosage (0.61). Optimized conditions yielded 48.5 g of hydrochar per 100 g of dry food waste, with an energy recovery efficiency of 68 %. The inclusion of TiO₂ nanoparticles as a catalyst significantly enhanced hydrochar properties, increasing carbon retention from 56.8 % to 77.6 %, bulk density from 0.37 g/cm³ to 0.89 g/cm³, and high heating value from 18.4 MJ/kg to 22.7 MJ/kg. These findings demonstrate the potential of ML-driven optimization for real-time control of HTC, reducing reliance on trial-and-error experimentation and advancing sustainable waste-to-energy conversion technologies.

Not all produced compost meets established quality standards, often resulting in environmental challenges. This study investigated the potential of using mature compost as a feedstock for biochar production, with a focus on evaluating the gas adsorption properties of the resulting biochars. Mature compost was utilized as a substrate, and the pyrolysis process involved heating samples within a temperature range of 400–650 °C, at 50 °C intervals, with heating rates of 10 °C·min⁻¹, 15 °C·min⁻¹, or 20 °C·min⁻¹ for a duration of 60 min. The resulting biochars were tested for their adsorption performance against a synthetic gas mixture simulating composting emissions (CO₂, CO, H₂S, NH₃, CH₄ in N₂). Our findings reveal a significant correlation between the pyrolysis temperature and the sorption characteristics of compost biochars. Specifically, biochars produced at temperatures of 550 °C, 600 °C, and 650 °C (with a heating rate of 10 °C·min⁻¹) demonstrated the highest efficacy in reducing emissions of CO₂, CH₄, and H₂S, achieving reductions of 69%, 69%, and 72%, respectively. However, these biochars exhibited lower adsorption capacity for CO and NH₃. Interestingly, biochars produced at 400 °C and 450 °C showed enhanced performance for CO adsorption. Compost biochar shows strong potential for gas adsorption, particularly for CO, CO₂, and H₂S. Due to its pronounced CH₄ sorption capacity, such biochar is better suited for mitigating emissions during composting rather than for biogas purification.

Microbial biodegradation represents a promising approach to addressing global plastic pollution, yet the metabolic pathways and environmental origins of polymer-degrading microorganisms remain incompletely characterized. This review synthesizes current knowledge on biodegradation mechanisms across major polymer classes and identifies key environmental reservoirs harboring native plastic-degrading microbiota. Biodegradation pathways differ fundamentally according to polymer chemistry. Polyesters such as PET undergo hydrolytic cleavage by PETases and MHETases, releasing terephthalic acid and ethylene glycol for assimilation via the β-ketoadipate pathway and the TCA cycle. Biodegradable polyesters (PLA, PBAT, PHAs, PCL) are similarly hydrolyzed by cutinases, lipases, and depolymerases. In contrast, polyolefins (PE, PP) and polystyrene lack hydrolyzable bonds and require oxidative attack by laccases, peroxidases, and alkane monooxygenases, followed by β-oxidation to acetyl-CoA. Three principal environmental reservoirs supply plastic-degrading microorganisms: contaminated ecosystems including landfills and the plastisphere; soil microbiota contributing ligninolytic fungi and actinomycetes; and compost environments yielding thermostable enzymes such as leaf-branch compost cutinase. Across all environments, microbial consortia demonstrate superior degradation efficiency compared to single-species cultures, reflecting the enzymatic complexity required for complete polymer mineralization. Understanding these pathways and their environmental origins provides a foundation for biological plastic waste management strategies.