Aug 2026· Journal of Environmental Management· Vol 416, pp.
130823
· 0 citations· 29 references
Medicine
TL;DR
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.
Abstract
Polyethylene terephthalate (PET) degradation is often limited by insufficient polymer depolymerization and the downstream conversion of hydrolysis products. In this study, Burkholderia cepacia ZY1 and Pseudomonas harudinis G1B were compared, and a two-strain consortium, YB2, was constructed at an optimal inoculation ratio of 4:5. ZY1 showed relatively stronger PET depolymerization-related activity, whereas G1B exhibited greater growth in bis(2-hydroxyethyl) terephthalate (BHET)- and mono(2-hydroxyethyl) terephthalate (MHET)-containing media and a trend toward faster BHET conversion. The hydrolytic activities of both strains were mainly cell associated, and both remained culturable, with stable relative proportions during 0-7 d of cocultivation. At pH 7.0 and 30 °C, YB2 achieved 4.30% ± 0.11% PET film mass loss after 3 d, significantly exceeding the individual strains. YB2 treatment caused surface erosion, ester-related structural changes, and increased residual PET crystallinity. The detection of BHET, MHET, and terephthalic acid (TPA) further supported PET depolymerization, while the release of ethylene glycol (EG) was also observed. YB2 converted 96.4% of BHET and 97.3% of MHET within 2 d and almost completely utilized TPA within 5 d. EG initially accumulated and then declined, suggesting possible subsequent microbial utilization. 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.
Polybutylene adipate terephthalate (PBAT) is prone to incomplete degradation, leading to environmental pollution and carbon resource waste. Biodegradation and valorization of waste plastics are essential for addressing plastic pollution and promoting a circular economy. Enzymatic degradation offers advantages, but free enzymes suffer from low stability and poor recyclability. Here, surface display technology was used to construct a cutinase Tfcut-DM display system in Escherichia coli BL21(DE3). The results showed that surface display significantly enhanced the stability and reusability of Tfcut-DM. Compared with free enzymes, its thermostability and pH stability increased by 11.9-fold and 42.1-fold, respectively, and approximately 80% of initial activity was retained after seven reuse cycles. Under optimized conditions, the surface-displayed strain released 255.9 µM of terephthalic acid (TPA) from PBAT films over 5 days, with near-complete degradation. To enable TPA valorization , the tph operon was introduced to C. necator H16 (CnH16-tph) for TPA-to-PHB conversion. A co-culture system comprising the surface-displayed strain and CnH16-tph was established for proof-of-concept one-pot conversion of PBAT to PHB. PHB accumulation is indirectly attributed to the TPA derived from PBAT degradation. Under optimized conditions, the maximum PHB yield reached 0.91 g/L. While isotopic tracing would be required for definitive carbon flux assignment, this indirect evidence strongly suggests the successful conversion of PBAT-derived TPA to PHB. This study provides a novel approach for the green degradation and resource utilization of waste PBAT, facilitating the recycling of discarded resources.
Jiali Liu, Jie Yang, Xin Wang et al.· Bioresource Technology· 0 citations
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.
Shi-Jing Deng, Qiaoqiao Guo, Yun-He An et al.· Microorganisms· 0 citations
Polyhydroxyalkanoates (PHAs) are biodegradable microbial polyesters that may reduce dependence on petroleum-derived plastics, but broader use remains constrained by production costs and tightly controlled cultivation. Thermophilic microorganisms have attracted increasing attention as promising PHA producers because they can be cultivated at elevated temperatures, reducing contamination risks and operational costs. In this study, a thermophilic Geobacillus sp. strain SL28 isolated from a Vietnamese hot spring was evaluated for its PHA-producing capability. Temperature, initial pH, carbon and nitrogen sources, C/N ratio, and cultivation time were examined. Intracellular inclusions were assessed by Sudan Black B and Nile Blue A staining and transmission electron microscopy, whereas the recovered polymer was characterized by FE-SEM, Fourier-transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), 1H- and 13C-nuclear magnetic resonance (NMR) spectroscopy, capillary viscometry, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and tensile testing. Under the optimized cultivation conditions identified by one-factor experimentation (50 °C, pH 7.0, sucrose, peptone, C/N 25:1, and 72 h), SL28 reached a dry cell weight of 2.215 ± 0.16 g/L and a PHA concentration of 1.383 ± 0.04 g/L, equivalent to 62.57 ± 2.82% of DCW. Structural characterization confirmed that the recovered polymer was poly(3-hydroxybutyrate) (PHB). The purified PHB also exhibited favorable thermal stability, a relatively high molecular weight, and satisfactory mechanical properties. These results demonstrate the potential of thermophilic Geobacillus sp. SL28 as a promising candidate for PHB production.
D. Q. Nguyen, T. Do, N. Lai et al.· Processes· 0 citations
Findings indicate that A. guillouiae I-MWF can mediate partial PET depolymerisation without assimilating the resulting monomers, while preferentially growing on lipid-like substrates, suggesting adaptation to hydrocarbon-rich environments.
Naheed Akhtar, A. Najjari, Anna Magnone et al.· BMC Microbiology· 0 citations
Polyethylene (PE) remains environmentally persistent due to its inert backbone and high molecular weight, with biodegradation hindered by low efficiency and unclear community-level mechanisms. In this study, we reconstructed a synthetic consortium, Z123, comprising Nitratireductor sp. Z-1 and Gordonia spp. Z-2 and Z-3 isolated from a consistent enrichment system. Z123 achieved 9.98% weight loss and 50.88% molecular weight reduction within 30 days, outperforming most consortia degrading pristine low-density polyethylene (LDPE). Integrated genomic and proteomic analyses suggested functional differentiation among consortium members involving oxidative activation, chain scission, and downstream metabolism. Gas chromatography-mass spectrometry (GC-MS) analysis further detected putative LDPE-associated extracellular compounds consistent with oxidative polymer modification. Recombinant MCO1 and Lcp3 modified LDPE in vitro, and their combined application caused greater depolymerization than either enzyme at the corresponding half dose, suggesting complementary catalytic contributions. Collectively, these results indicate that functional differentiation and cooperative interactions contribute to enhanced LDPE degradation by Z123. This work provides mechanistic insights into consortium-based plastic biodegradation and supports the rational design of microbial platforms for plastic waste management.
Zhen Rong, Jun-Qing Chen, Yue-Hong Wu et al.· Water Research· 0 citations
Returning waste polyethylene terephthalate (PET) to its original monomers (e.g., terephthalic acid (TPA)) constitutes closed-loop molecular recycling. Hydrolysis can accomplish this conversion and ytterbium triflate (Yb(OTf)3) is an effective catalyst. PET hydrolysis with Yb(OTf)3 at 220 °C for 40 min resulted in 92% PET conversion and 66% TPA yield, whereas the uncatalyzed reaction produced just 0.1% TPA yield. We investigated the effects of temperature (160–250 °C), reaction time (6–960 min), catalyst loading (0.9–37 mol % relative to moles of PET repeat units), PET particle size, and PET:water w/w ratio (1:10–1:2) on Yb(OTf)3-catalyzed PET hydrolysis. The PET disappearance kinetics followed a rate law that was pseudo-first-order in PET with a temperature-dependent induction time. The Arrhenius plot showed two regimes. At 205 °C or greater, the activation energy was 54 ± 12 kJ/mol. This regime may reflect the catalytic kinetics for hydrolysis of PET in a softened, swollen, or molten state. The reaction order with respect to Yb(OTf)3 in this regime was 0.77 ± 0.02. For hydrolysis below 205 °C, the activation energy was 165 ± 13 kJ/mol. This regime may reflect the kinetics for PET in a more rigid solid-like state with diffusion of water and/or catalyst within PET being a rate-limiting process. Smaller PET particles reacted more quickly than larger ones in this regime, consistent with diffusion being rate limiting and with the rate being favored by increased PET surface area. Mono-2-hydroxyethyl terephthalate (MHET) was the key reaction intermediate. The PET:water w/w ratio played a crucial role in reaction outcomes, as the TPA yield decreased by about 40% when the ratio was reduced from 1:10 to 1:2.
P. Talaei, Phillip E. Savage· ACS Omega· 0 citations
