Search Results (114)

Fungal lytic polysaccharide monooxygenases (LPMOs) have revolutionized the field of biomass degradation by introducing an oxidative mechanism that complements traditional hydrolytic enzymes. These copper-dependent enzymes catalyze the cleavage of glycosidic bonds in recalcitrant polysaccharides such as cellulose, hemicellulose, and chitin, through the activation of molecular oxygen (O₂) or hydrogen peroxide (H₂O₂). Their catalytic versatility is intricately modulated by structural features, including the histidine brace active site, surface-binding loops, and, in some cases, appended carbohydrate-binding modules (CBMs). The oxidation pattern, whether at the C1, C4, or both positions, is dictated by subtle variations in loop architecture, amino acid microenvironments, and substrate interactions. LPMOs are embedded in a highly synergistic fungal enzymatic system, working alongside cellulases, hemicellulases, lignin-modifying enzymes, and oxidoreductases to enable efficient lignocellulose decomposition. Industrial applications of fungal LPMOs are rapidly expanding, with key roles in second-generation biofuels, biorefineries, textile processing, food and feed industries, and the development of sustainable biomaterials. Recent advances in genome mining, protein engineering, and heterologous expression are accelerating the discovery of novel LPMOs with improved functionalities. Understanding the balance between O₂- and H₂O₂-driven mechanisms remains critical for optimizing their catalytic efficiency while mitigating oxidative inactivation. As the demand for sustainable biotechnological solutions grows, this narrative review highlights how fungal LPMOs function as indispensable biocatalysts for the future of the Circular Bioeconomy and green industrial processes. Full article

This study reports the development of a sustainable biocatalyst system for free fatty acid (FFA) production from cocoa bean shell (CBS) oil using Burkholderia cepacia lipase (BCL). CBS was explored as both a support material and a reaction substrate. Six immobilized systems were prepared using organic (CBS), inorganic (silica), and hybrid (CBS–silica) supports via physical adsorption or covalent binding. Among them, the covalently immobilized enzyme on CBS (ORG-CB) showed the most balanced performance, achieving a catalytic efficiency (Ke) of 0.063 mM⁻¹·min⁻¹ (18.6% of the free enzyme), broad pH–temperature tolerance, and over 50% activity retention after eight reuse cycles. Thermodynamic analysis confirmed enhanced thermal resistance for ORG-CB (Ed = 32.3 kJ mol⁻¹; ΔH‡ = 29.7 kJ mol⁻¹), while kinetic evaluation revealed that its thermal deactivation occurred faster than for the free enzyme under prolonged heating. In application trials, ORG-CB reached 60.1% FFA conversion from CBS oil, outperforming the free enzyme (49.9%). These findings validate CBS as a dual-function material for enzyme immobilization and valorization of agro-industrial waste. The results also reinforce the impact of immobilization chemistry and support composition on the operational and thermal performance of biocatalysts, contributing to the advancement of green chemistry strategies in enzyme-based processing. Full article

Esterification is a key transformation in the production of lubricants, pharmaceuticals, and fine chemicals. Conventional processes employing homogeneous acid catalysts suffer from limitations such as corrosive byproducts, energy-intensive separation, and poor catalyst reusability. This review provides a comprehensive overview of heterogeneous catalytic systems, including ion exchange resins, zeolites, metal oxides, mesoporous materials, and others, for improved ester synthesis. Recent advances in membrane-integrated reactors, such as pervaporation and nanofiltration, which enable continuous water removal, shifting equilibrium and increasing conversion under milder conditions, are reviewed. Dual-functional membranes that combine catalytic activity with selective separation further enhance process efficiency and reduce energy consumption. Enzymatic systems using immobilized lipases present additional opportunities for mild and selective reactions. Future directions emphasize the integration of pervaporation membranes, hybrid catalyst systems combining biocatalysts and metals, and real-time optimization through artificial intelligence. Modular plug-and-play reactor designs are identified as a promising approach to flexible, scalable, and sustainable esterification. Overall, the interaction of catalyst development, membrane technology, and digital process control offers a transformative platform for next-generation ester synthesis aligned with green chemistry and industrial scalability. Full article

Efficient hydrolysis of cellulose in agricultural waste (e.g., coconut fiber) is critical for biorefining processes such as second-generation bioethanol (2G ethanol) production. However, free cellulases suffer from low thermal stability and challenges in recovery. To address this, we developed cross-linked enzyme aggregates (CLEAs) combined with magnetic nanoparticles (magnetic CLEAs, m-CLEAs) to enhance enzyme stability and reusability. In this context, solutions of ethanol, acetone, and ammonium sulfate were used to prepare enzymatic aggregates, with subsequent use of glutaraldehyde and magnetic nanoparticles to obtain the biocatalysts. The addition of bovine serum albumin (BSA) protein was also tested to improve immobilization. Biocatalysts with ethanol and acetone performed better. Acetone (AC) and BSA yielded the highest enzymatic activities (287.27 ± 42.59 U/g for carboxymethyl cellulase (CMCase) with Celluclast; 425.37 ± 48.11 U/g for CMCase with Cellic CTec2). Magnetic nanoparticles were incorporated to expand the industrial applicability, producing m-CLEAs with excellent thermal stability and high catalytic activities. The m-CLEA–Celluclast–AC–BSA–GA 5% maintained 58% of its activity after 72 h at 70 °C. The m-CLEA–Celluclast-AC–BSA–GA 2.5% proved effective in hydrolyzing coconut fiber and isolated cellulose, producing up to 0.91 ± 0.01 g/L of glucose and 2.7 ± 0.15 g/L of glucose, respectively, after 72 h. Therefore, this approach supports sustainability by using coconut fiber, which is often discarded into the environment. Full article

Artificial enzymes or nanozymes (NZs) are gaining significant attention in biotechnology due to their stability and cost-effectiveness. NZs can offer several advantages over natural enzymes, such as enhanced stability under harsh conditions, longer shelf life, and reduced production costs. The booming interest in NZs is likely to continue as their potential applications expand. In our previous studies, we reported the “green” synthesis of copper hexacyanoferrate (gCuHCF) using the oxidoreductase flavocytochrome b₂ (Fcb₂). Organic–inorganic micro-nanoparticles were characterized in detail, including their structure, composition, catalytic activity, and electron-mediator properties. An SEM analysis revealed that gCuHCF possesses a flower-like structure well-suited for concentrating and stabilizing Fcb₂. As an effective peroxidase (PO) mimic, gCuHCF has been successfully employed for H₂O₂ detection in amperometric sensors and in several oxidase-based biosensors. In the current study, we demonstrated the uniqueness of gCuHCF that lies in its multifunctionality, serving as a PO mimic, a chemosensor for ammonium ions, a biosensor for L-lactate, and exhibiting perovskite-like properties. This exceptional ability of gCuHCF to enhance fluorescence under blue light irradiation is being reported for the first time. Using gCuHCF as a PO-like NZ, novel oxidase-based sensors were developed, including an optical biosensor for L-arginine analysis and electrochemical biosensors for methanol and glycerol determination. Thus, gCuHCF, synthesized via Fcb₂, presents a promising platform for the development of amperometric and optical biosensors, bioreactors, biofuel cells, solar cells, and other advanced devices. The innovative approach of utilizing biocatalysts for nanoparticle synthesis highlights a groundbreaking direction in materials science and biotechnology. Full article

Palladium nanoparticles (PdNPs) are transforming the landscape of modern catalysis and offer sustainable and efficient alternatives to traditional catalysts for cross-coupling reactions. Owing to their exceptional surface area-to-volume ratio, PdNPs exhibit superior catalytic activity, selectivity, and recyclability, making them ideal for greener chemical processes. Recent innovations have focused on improving the stability and reusability of PdNPs through environmentally benign approaches, such as water-based reactions, renewable stabilizers, and magnetic nanoparticle supports. Advances in catalyst design, including PdNP immobilization on magnetic nanosilica for enhanced recyclability in Suzuki–Miyaura reactions, nitrogen-doped carbon nanosheets achieving up to ninefold improvements in turnover frequencies, and biodegradable biopolymer matrices that reduce environmental impact, have effectively addressed key challenges such as catalyst leaching, support degradation, and agglomeration. The shift from conventional catalysis to these cutting-edge nanocatalytic techniques signifies a critical movement toward sustainable chemistry, positioning PdNPs at the forefront of industrial applications and the future of eco-friendly chemical synthesis. Full article

A national energy crisis has emerged in South Africa due to the country’s increasing energy needs in recent years. The reliance on fossil fuels, especially oil and gas, is unsustainable due to scarcity, emissions, and environmental repercussions. Researchers from all over the world have recently concentrated their efforts on finding carbon-free, renewable, and alternative energy sources and have investigated microbiology and biotechnology as a potential remedy. The usage of microbial electrolytic cells (MECs) and microbial fuel cells (MFCs) is one method for resolving the problem. These technologies are evolving as viable options for hydrogen and bioenergy production. The renewable energy technologies initiative in South Africa, which is regarded as a model for other African countries, has developed in the allocation of over 6000 MW of generation capacity to bidders across several technologies, primarily wind and solar. With a total investment value of R33.7 billion, the Eastern Cape’s renewable energy initiatives have created 18,132 jobs, with the province awarded 16 wind farms and one solar energy farm. Utilizing wastewater as a source of energy in MFCs has been recommended as most treatments, such as activated sludge processes and trickling filter plants, require roughly 1322 kWh per million gallons, whereas MFCs only require a small amount of external power to operate. The cost of wastewater treatment using MFCs for an influent flow of 318 m³ h⁻¹ has been estimated to be only 9% (USD 6.4 million) of the total cost of treatment by a conventional wastewater treatment plant (USD 68.2 million). Currently, approximately 500 billion cubic meters of hydrogen (H₂) are generated worldwide each year, exhibiting a growth rate of 10%. This production primarily comes from natural gas (40%), heavy oils and naphtha (30%), coal (18%), electrolysis (4%), and biomass (1%). The hydrogen produced is utilized in the manufacturing of ammonia (49%), the refining of petroleum (37%), the production of methanol (8%), and in a variety of smaller applications (6%). Considering South Africa’s energy issue, this review article examines the production of wastewater and its impacts on society as a critical issue in the global scenario and as a source of green energy. Full article

Caffeic acid phenethyl ester (CAPE) represents a valuable ester of caffeic acid, which, over time, has demonstrated remarkable pharmacological properties. In general, the ester is obtained in organic solvents, especially by the esterification reaction of caffeic acid (CA) and 2-phenylethanol (PE). In this context, the purpose of this study was the use of the “one pot” system to synthesize CAPE through biocatalysis with various lipases in a choline-chloride-based DES system, employing the “2-in-1” concept, where one of the substrates functions as both reactant and solvent. The synthesis process of CAPE is contingent on the molar ratio between CA and PE; thus, this factor was the primary subject of investigation, with different molar ratios of CA and PE being studied. Furthermore, the impact of temperature, time, the nature of the biocatalyst, and the water loading of the DES system was also examined. This ‘green’ synthesis method, which has demonstrated encouraging reaction yields (%), could secure and maintain the therapeutic potential of CAPE, mainly due to the non-toxic character of the reaction medium. Full article

This study explores the purification, characterization, and application of laccases from Trametes hirsuta CS5 for degrading synthetic dyes as models of emerging contaminants. Purification involved ion exchange chromatography, molecular exclusion, and chromatofocusing, identifying th ree laccase isoforms: ThIa, ThIb, and ThII. Characterization included determining pH and temperature stability, kinetic parameters (K_m, K_cat), and inhibition constants (K_i) for inhibitors like NaN₃, SDS, TGA, EDTA, and DMSO, using 2,6-DMP and guaiacol as substrates. ThII exhibited the highest catalytic efficiency, with the lowest K_m and highest K_cat. Optimal activity was observed at pH 3.5 and 55 °C. Decolorization tests with nine dyes showed that ThII and ThIa were particularly effective against Acid Red 44, Orange II, Indigo Blue, Brilliant Blue R, and Remazol Brilliant Blue R. ThIb displayed higher activity towards Crystal Violet and Acid Green 27. Among substrates, guaiacol showed the highest K_cat, while 2,6-DMP was preferred overall. Inhibitor studies revealed NaN₃ as the most potent inhibitor. These results demonstrate the significant potential of T. hirsuta CS5 laccases, especially ThIa and ThII, as biocatalysts for degrading synthetic dyes and other xenobiotics. Their efficiency and stability under acidic and moderate temperature conditions position them as promising tools for sustainable wastewater treatment and environmental remediation. Full article

The value of branched esters comes from the special properties they have in cold environments, which allow them to remain liquid over a wide range of temperatures. These properties make them useful for application in the cosmetic industry or as lubricant additives. This paper presents the studies carried out to ascertain the operational feasibility of the enzymatic esterification of 2-methylpentanoic acid (MPA) with 1,10-decanediol (DD), with the objective of obtaining a novel molecule: decane-1,10-diyl bis(2-methylpentanoate) (DDBMP). The enzymatic reaction is conducted in a thermostated batch reactor, utilizing the commercially available immobilized lipase Lipozyme^® 435 in a solvent-free medium. The reaction conversion is determined by an acid number determination and a gas chromatographic analysis. The most optimal result is achieved at a temperature of 80 °C, a biocatalyst concentration of 2.5% (w/w), and a non-stoichiometric substrate relation. A preliminary economic study and the calculation of Green Metrics has established that the operation with a 30% molar excess of acid is the best option to obtain a product with 92.6% purity at a lower cost than the other options and in accordance with the 12 Principles of Green Chemistry. The synthetized diester has a viscosity index of 210, indicating that this new molecule can be used as a biolubricant at extreme temperatures. Full article

Lipase, a green biocatalyst, finds extensive application in the food sector. Enhancing the thermal stability of lipase presents both challenges and opportunities within the food industry. This research employed multiple rounds of cross-screening using tools like FoldX and I-Mutant 3.0 to strategically design mutations for Rhizomucor miehei lipase (RML), resulting in eight unique single-point mutation designs. E230I, N120M, and N264M have been confirmed experimentally to be potential combination mutation candidates. The resulting triple mutant N120M/E230I/N264M showed a higher thermal stability, with an optimum temperature of 55 °C, 10 °C higher than that of the wild-type RML. The half-life was extended from 46 to 462 min at 50 °C. Furthermore, the catalytic activity of N120M/E230I/N264M on camphor tree seed oil increased by 140% to 600 U/mg, which aids in the production of novel structured lipids. Using molecular docking and molecular dynamics simulations, we analyzed the molecular mechanism of enhanced thermal stability. This study validated the efficacy and dependability of computer-aided design to generate heat-resistant RML mutants and indicated that RML N120M/E230I/N264M lipase can be used as an effective biocatalyst for fat processing in the food industry. Full article

In the modern world, the principles of the bioeconomy are becoming increasingly important. Recycling and reusability play a crucial role in sustainable development. Green chemistry is based on enzymes, but immobilized biocatalysts are still often designed with synthetic polymers. Insoluble carriers for immobilized biocatalysts, particularly those derived from agro-industrial waste such as mesoporous lignocellulosic materials, offer a promising alternative. By using waste materials as support for enzymes, we can reduce the environmental impact of waste disposal and contribute to the development of efficient bioprocessing technologies. The current study aimed to assess the possibility of using apple and chokeberry pomace as carriers for the immobilization of Palatase 20000L (lipase from Rhizomucor miehei). The analysis of lignocellulosic materials revealed that chokeberry pomace has a higher neutral detergent fiber (NDF) and lignin contents than apple pomace. Moreover, Scanning Electron Microscopy (SEM) observations indicated similar compact structures in both pomaces. The lipase activity assays demonstrated that immobilization of lipase from R. miehei onto apple and chokeberry pomace improves their properties, especially the synthetic activity. The findings highlight the potential of utilizing fruit pomaces not only as a source of bioactive compounds but also in enhancing enzyme stability for industrial applications. Full article

In the current study, pyromellitimide benzoyl thiourea cross-linked chitosan (PIBTU-CS) hydrogel, was evaluated as a green biocatalyst for the efficient synthesis of novel thiazole derivatives. The PIBTU-CS hydrogel showcased key advantages, such as an expanded surface area and superior thermal stability, establishing it as a potent eco-friendly catalyst. By employing PIBTU-CS alongside ultrasonic irradiation, we successfully synthesized a series of novel thiazoles through the reaction of 2-(4-((2-carbamothioylhydrazineylidene)methyl)phenoxy)-N-(4-chlorophenyl)acetamide with a variety of hydrazonoyl halides (6a–f) and α-haloketones (8a–c or 10a,b). A comparative analysis with TEA revealed that PIBTU-CS hydrogel consistently delivered significantly higher yields. This synthetic strategy provided several benefits, including mild reaction conditions, reduced reaction times, and consistently high yields. The robustness of PIBTU-CS was further underscored by its ability to be reused multiple times without a substantial reduction in catalytic efficiency. The structures of the synthesized thiazole derivatives were meticulously characterized using a range of analytical techniques, including IR, ¹H-NMR, ¹³C-NMR, and mass spectrometry (MS), confirming their successful formation. These results underscore the potential of PIBTU-CS hydrogel as a sustainable and recyclable catalyst for the synthesis of heterocyclic compounds. Additionally, all synthesized products were tested for their anticancer activity against HepG2-1 cells, with several new compounds exhibiting good anticancer effects. Full article

Mesotrione (MES) is a new environmental pollutant. Some reports have indicated that microbial enzymes could be utilized for MES degradation. Laccase is a green biocatalyst whose potential use in environmental pollutant detoxification has been considered limited due to its poor stability and reusability. However, these issues may be addressed using enzyme immobilization. In the present study, we sought to optimize conditions for laccase immobilization, to analyze and characterize the characteristics of the immobilized laccase, and to compare its enzymatic properties to those of free laccase. In addition, we studied the ability of laccase to degrade MES, and analyzed the metabolic pathway of MES degradation by immobilized laccase. The results demonstrated that granular zinc oxide material (G-ZnO) was successfully used as the carrier for immobilization. G-ZnO@Lac demonstrated the highest recovery of enzyme activity and exhibited significantly improved stability compared with free laccase. Storage stability was also significantly improved, with the relative enzyme activity of G-ZnO@Lac remaining at about 54% after 28 days of storage (compared with only 12% for free laccase). The optimal conditions for the degradation of MES by G-ZnO@Lac were found to be 10 mg, 6 h, 30 °C, and pH 4; under these conditions, a degradation rate of 73.25% was attained. The findings of this study provide a theoretical reference for the laccase treatment of 4-hy-droxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide contamination. Full article

Alginate is a naturally occurring polymer derived from brown algae biomass, which has numerous applications in various fields. Chemical modification of alginate is widely used to improve alginate’s physicochemical properties and provide new potential for multiple applications. In this article, we modified alginate with L-DOPA, using periodate oxidation and reductive amination, to obtain more suitable biopolymer for biocatalyst immobilization and hydrogel formation. Obtained modified alginate was used for the immobilization of laccase on cell walls. For this purpose, laccase from Streptomyces cyaneus was expressed on the surface of Saccharomyces cerevisiae EBY100 cells. The obtained cell wall laccase was immobilized within L-DOPA-alginate beads by crosslinking the L-DOPA-alginate with calcium ions and laccase. The effect of additional crosslinking of beads by green light-induced photopolymerization with eosin Y was investigated. The immobilized laccase systems were used for dye decolorization and investigated in multiple treatment processes. Beads with L-DOPA-alginate with a higher degree of modification (5.0 mol%) showed higher enzymatic activity and better decolorization efficiency than those with a lower degree of modification (2.5 mol%). Obtained immobilized biocatalysts are suitable for decolorizing dye Evans Blue due to their high efficiency and reusability. Full article