In the pulp and paper industry, residual sticky substances accumulate during white water circulation, forming deposits that cause paper defects and increase costs. Cutinase is a promising biocatalyst for mitigating stickies, but its industrial application is limited by inherent catalytic constraints. To address this, a strategy integrating structural alignment, virtual screening, and computer-aided design was employed to remodel the substrate-binding pocket of cutinase from Humicola insolens (HiC). Through iterative recombination, variants C11 and E12 were developed, exhibiting enhanced degradation performance toward polyvinyl acetate (PVAc) and polyethyl acrylate (PEA), respectively. C11 increased acetic acid production from PVAc by 1.73-fold compared to the parental M8 variant, while E12 increased ethanol production from PEA by 3.17-fold. Notably, C11 and E12 displayed half-life (t1/2) of 205.9 h and 51.8 h at 70 °C, corresponding to over 20000-fold and 5000-fold improvements over the wild-type HiC (t1/2 = 0.01 h at 70 °C), while retaining more than 88% activity at pH 11.0. Molecular dynamics (MD) simulations revealed that the enhanced catalytic activity originated from optimized enzyme-substrate conformations, characterized by shortened nucleophilic attack distances and converged oxyanion hole distributions, stabilizing substrates in catalytically favorable near-attack conformations. Collectively, these engineered cutinase variants represent promising biocatalysts for industrial stickies control, offering an efficient and environmentally friendly strategy.
This study presents the systematic review and analysis of scientific articles on cellulose nanofibril (CNF) production from vegetable fibers, with a focus on environmentally friendly methods. The research followed the PRISMA protocol, selecting works that addressed complete extraction processes starting from vegetal fibers and reporting parameters such as length-to-diameter ratio (L/D), crystallinity, and yield of CNFs. Based on the bibliographic findings, a process flowchart and an experimental design were developed for CNF extraction from peach palm sheath, combining glycerol swelling, single-screw extrusion, and dilute acid hydrolysis (0.4–0.6% H₂SO₄). The choice of this route was based on its potential to promote controlled mechanical shear after glycerol plasticization, facilitating the opening of the cell wall and selective removal of amorphous regions while preserving crystallinity. The proposed methodology, supported by literature evidence, offers a technically feasible and sustainable approach for the valorization of agro-industrial residues, with potential for scaling up to pilot and industrial levels.
Felipe Pinto, Oliveira. Federal, Marina R. de Andrade1 et al.· JOURNAL OF BIOENGINEERING, T...· 0 citations
Efficient fractionation of lignocellulose is essential for sustainable biorefining but remains challenged by the structural recalcitrance of plant cell walls. In this study, several ternary deep eutectic solvents (TDESs) were designed to enhance corn stover deconstruction. Systematic screening of various organic acids as the third component led to the selection of tartaric acid (TA) for synthesizing the novel TDES composed of Cetyltrimethylammonium bromide (CTAB), ethylene glycol (EG), and TA at an optimal molar ratio of 1:4:1.8. Under optimal conditions, this process achieved removal efficiencies of 81.0% for xylan and 74.8% for lignin, producing furfural at 63.0% of the theoretical yield from xylan conversion and xylo-oligosaccharides at 33.2% based on the initial xylan content. Concurrently, substrate accessibility increased to 583.6 mg/g, while surface lignin area decreased to 597.2 m2/g, collectively contributing to an impressive saccharification efficiency of 86.9%. Multiscale characterization by SEM, FT-IR, and XRD showed that TDES disrupted the compact cell-wall morphology, attenuated lignin- and hemicellulose-associated spectral features, and increased the cellulose crystallinity index. Mass and energy flow analysis indicated that 87.6% of the theoretical energy contained in cellulose was recovered in the product streams, with 5.16 MJ of energy effectively recovered in lignin-rich stream. Static electrostatic potential calculations and independent gradient model analysis explored potential non-covalent interactions between TDES components and representative lignocellulosic units, providing theoretical insight into the interactions that may contribute to the pretreatment performance. This work provides a tailored approach for designing highly selective TDES to alter corn stover structure and maximize the agricultural residue valorization.
Shao-Jie Jiang, Yujie Zeng, Yilu Zhang et al.· International Journal of Bio...· 0 citations
The increasing accumulation of plastic waste has intensified efforts to identify sustainable biodegradable alternatives. Polyhydroxyalkanoates (PHAs) are microbial polyesters with properties similar to conventional plastics; however, their commercial feasibility is limited by high production costs. This study investigated the use of oil palm waste, specifically palm kernel meal (PKM) and empty fruit bunch (EFB), as feedstocks for PHA production by Paraburkholderia sp. PFN29. Biomass pretreatment used sodium hydroxide (1-5% w/v) followed by hydrogen peroxide (3% v/v), and enzymatic hydrolysis with pectinase, xylanase, and cellulase. Reducing sugars were quantified using the dinitrosalicylic acid (DNS) method, and morphological changes were examined via scanning electron microscopy (SEM). Optimal saccharification with 3% (w/v) NaOH at 50°C for 48 h yielded 10.53±0.33 and 21.02±0.38 mg/mL reducing sugars from PKM and EFB, respectively. Glucose was the predominant sugar in both hydrolysates. PHA biosynthesis was assessed under various carbon- and nitrogen-supplementation conditions. The EFB hydrolysate at 100 ml supplemented with 0.1 g NH₄Cl produced the highest PHA concentration (1.12±0.02 g/L), PHA content (59.02%), and productivity (0.01 g/L/h), which was comparable to that of the mineral medium control. The PKM hydrolysate supported optimal PHA production without supplementation (PHA content, 39.02%). Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed PHB-type PHA production. These findings indicate that palm oil residues, particularly EFB hydrolysates under optimized nitrogen conditions, are promising substrates for sustainable PHA production.
Sumintra Chaimongkol, T. Sriyapai, Pichapak Sriyapai· Current Applied Science and...· 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 extensive use of synthetic polymers has raised significant environmental concerns due to their non-biodegradable nature and persistence in the environment. Cellulose-based materials have attracted considerable interest owing to their excellent inherent properties which enable their wide range of industrial and biomedical applications. In this study, an integrated approach (hydrothermal process, organosolv delignification and chlorine-free bleaching) was evaluated to obtain high-purity cellulose fiber from sugarcane bagasse (SCB). The untreated SCB was first subjected to hydrothermal process under varying experimental conditions defined by a central composite design (170–190 °C, 30–50 min) using a solid-to-liquid ratio of 1:10 (w/v). The hydrothermally pretreated solid was subsequently delignified using an organosolv process with an aqueous solution of 40% (v/v) ethanol and 0.1% (w/v) NaOH at 180 °C for 20 min. Finally, the organosolv delignified SCB was bleached with 1% (v/v) H2O2 and 1% NaOH (w/v) at 80 °C for 1 h. The bleached cellulose fiber exhibited a composition of 97.79 ± 0.19% cellulose, 1.10 ± 0.14% lignin and 0.23 ± 0.13% hemicellulose. XRD analysis displayed a notable increase in the crystallinity index from 52.2% in untreated SCB to 70.7% in the bleached cellulose fibers (BCF). Furthermore, FTIR revealed the disappearance of characteristic lignin and hemicellulose peaks at 1729, 1602, 1512 and 1240 cm−1 while the intensity of cellulose bands including the crystallinity-associated peaks at 1432 and 1320 cm−1 were preserved. The SEM images further confirmed significant transformation with distorted vascular tissue and exposed cellulose fibrils indicating extensive defibrillation.
Ezekiel O. Faluyi, R. M. Rodríguez-Jasso, R. Belmares-Cerda et al.· Applied Sciences· 0 citations
The development of efficient enzymatic strategies for poly(lactic acid) (PLA) recycling remains limited by the insufficient catalytic performance of single enzymes and the lack of mechanistic understanding of multi-enzyme cooperation. In this study, a newly screened cutinase, Cr14CLE, was characterized and, for the first time, systematically combined with proteinase K to investigate their cooperative degradation of PLA nonwoven fabric. Comprehensive structural and physicochemical analyses, including GPC, FT-IR, XRD, SEM, and thermal analysis, were employed to track the dynamic evolution of PLA during enzymatic hydrolysis. Notably, the dual-enzyme system exhibited a significantly enhanced degradation efficiency, achieving 71.3% degradation within 12 h at a total enzyme loading of 300 U, which exceeded the theoretical additive effects of individual enzymes. This enhancement was quantitatively attributed to a complementary catalytic interplay between Cr14CLE and proteinase K. Importantly, this study reveals a previously uncharacterized multistage degradation pathway, involving initial activation of less ordered regions, followed by destabilization of crystalline domains and eventual fiber fragmentation. These findings not only introduce Cr14CLE as a promising biocatalyst but also establish a mechanistic framework for designing synergistic enzymatic systems for efficient PLA biorecycling.
Ying Sun, Jingwen Zhang, Guoqiang Zhang et al.· Textile research journal· 0 citations
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