According to these findings, glucosamine offers excellent structural stability, compactness, and preservation of active site integrity, highlighting its potential use as a biocompatible cross-linker in immobilized laccase systems for industrial and environmental PET degradation applications.
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.
Jiarong Qiu, Yufeng Jin, Liangqing Zhang et al.· Journal of Environmental Man...· 0 citations
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
The depletion of fossil fuels and concerns over climate change have driven interest in lignocellulosic biomass (LCB) as a sustainable feedstock for biofuel production. Cellulose, the major biomacromolecular component of LCB, is efficiently converted into fermentable sugars through enzymatic hydrolysis; however, conventional pretreatment methods are energy-intensive and environmentally unfavourable. Deep eutectic solvents (DESs), particularly those derived from natural components, have emerged as green alternatives for biomass processing. For integrated single-pot bioconversion, DESs must be compatible with cellulase enzymes. In this study, the stability and activity of cellulase were evaluated in the presence of fourteen different DESs using experimental and computational approaches. The results show that choline chloride-polyol based DESs significantly enhance cellulase stability and catalytic activity, highlighting their potential as cellulase compatible media for sustainable one-pot lignocellulosic biomass conversion. Fluorescence spectroscopic analyses combined with molecular dynamics (MD) simulations revealed that cellulase adopts a compact and stable conformation while preserving its solvation shell. These findings highlight that careful selection of DESs is critical for the development of efficient DES-based biomass conversion processes.
Madushmita Hatimuria, Jyoti Vishwakarma, V. Ananya et al.· International Journal of Bio...· 0 citations
Lactobionic acid (LBA) is a compound that, in the last decade, has become critically important due to its potential applications in the food, chemical, pharmaceutical, and cosmetic industries. Enzymatic biosynthesis in the presence of a redox mediator is one method of producing LBA biologically. Cellobiose dehydrogenase (CDH) oxidizes the lactose to lactobionic acid, while laccase (LAC) enables the regeneration of the redox mediator (ABTS), which acts as an electron acceptor for CDH. The aim of this study was to develop an effective immobilized enzymatic system for the production of LBA. Two enzymes were used in the experiment: CDH from Phanerodontia chrysosporium (PchCDH) and LAC from Cerrena unicolor (CuLAC), which were immobilized on precipitated silica (Sipernat 22) activated by APTES and PEI. The immobilization process increased enzyme stability, improved the efficiency of LBA synthesis, and reduced costs, particularly in the context of using Sipernat 22 silica, which is inexpensive and widely used across various industries. The co-immobilization of both enzymes on the carrier proved to be the most effective approach, achieving a 90% conversion of lactose to lactobionic acid after ten cycles of synthesis. Comprehensive biochemical characterization, including protein loading, catalytic activity, and optimal pH, is provided in the main text.
Wiktoria Piątek-Gołda, Monika Osińska-Jaroszuk, M. Grąz et al.· Molecules· 0 citations
Efficient conversion of agricultural waste into fermentable sugars is central to sustainable second-generation biofuel technologies. This study reports the covalent immobilization of amyloglucosidase onto a magnetic silver nanoparticle (Ag-MNP) hybrid support for the saccharification of cassava peel. The Ag-MNP hybrid support was employed to combine magnetic recovery with a favourable immobilization microenvironment for enhanced catalytic performance during cassava peel saccharification. X-ray diffraction identified a multi-phase iron oxide system comprising maghemite, hematite, and goethite, with a mesoporous architecture of 18-20 nm pore diameter. Covalent enzyme attachment via glutaraldehyde-mediated imine bond formation was confirmed by infrared spectroscopy. The immobilized biocatalyst achieved 92.32% total reducing sugar recovery within 50 min, surpassing the free enzyme performance of 86.87% under identical conditions. Kinetic analysis revealed an elevated maximum reaction rate of 6.4 μmol min-1, compared with 5.0 μmol min-1 for the free enzyme, attributed to favourable active-site orientation and the physicochemical properties of the Ag-MNP hybrid support. Chromatographic analysis confirmed glucose as the dominant hydrolysate product at 90.26%. The biocatalyst retained 54% of its initial activity after seven operational cycles at pH 5.0 and 65 °C. No inhibitory byproducts were detected under the conditions tested, supporting its potential as a reusable biocatalyst for generating fermentable sugars for bioethanol production.
O. A. Falowo, B. Oladipo, Precious O. Adeyemo et al.· Carbohydrate Research· 0 citations
Microplastic pollution is a pervasive global challenge, with millions of tons of plastic entering terrestrial and aquatic ecosystems each year and persisting across diverse environmental compartments. Conventional physical and chemical remediation strategies remain energy-intensive and inefficient, highlighting the need for scalable biological alternatives. Here, we synthesize recent advances in lipase-mediated degradation of ester-bond-containing plastics and propose a unifying framework for programmable biodegradation, in which enzyme activity, substrate accessibility, and downstream metabolism are systematically coordinated. Lipases (EC 3.1.1.3) can hydrolyze synthetic polyesters, including polyethylene terephthalate (PET), polyurethane (PU), polylactide (PLA), and polycaprolactone (PCL), but their performance is constrained by polymer crystallinity, limited environmental stability, and restricted substrate specificity. Integrating insights from multi-omics discovery, artificial intelligence-guided enzyme engineering, and systems-level design reveals emerging strategies to enhance catalytic efficiency and environmental robustness. Although engineered enzyme systems can achieve high depolymerization and monomer recovery under controlled conditions, translation to real environments remains limited by diffusion constraints, enzyme inactivation, and regulatory considerations. Reframing plastic degradation as a multi-scale, designable system rather than a single-enzyme process highlights opportunities for coupling protein engineering with controlled deployment, including biofilm-based localization and metabolic pathway integration, to enable more effective and environmentally relevant microplastic remediation.
Debashrita Majumder, Anushree Dutta, D. Lahiri et al.· Preparative Biochemistry & B...· 0 citations