Immobilization of β-glucosidase onto silicon oxide nanoparticles and augment of phenolics in sugarcane juice

Recent Advances and Perspectives on Food-Grade Immobilisation Systems for Enzymes

The use of enzyme immobilisation is becoming increasingly popular in beverage processing, as this method offers significant advantages, such as enhanced enzyme performance and expanded applications, while allowing for easy process termination via simple filtration. This literature review analysed approximately 120 articles, published on the Web of Science between 2000 and 2023, focused on enzyme immobilisation systems for beverage processing applications. The impact of immobilisation on enzymatic activity, including the effects on the chemical and kinetic properties, recyclability, and feasibility in continuous processes, was evaluated. Applications of these systems to beverage production, such as wine, beer, fruit juices, milk, and plant-based beverages, were examined. The immobilisation process effectively enhanced the pH and thermal stability but caused negative impacts on the kinetic properties by reducing the maximum velocity and Michaelis-Menten constant. However, it allowed for multiple reuses and facilitated continuous flow processes. The encapsulation also allowed for easy process control by simplifying the removal of the enzymes from the beverages via simple filtration, negating the need for expensive heat treatments, which could result in product quality losses.

Improving the catalytic activity of β-glucosidase from Coniophora puteana via semi-rational design for efficient biomass cellulose degradation

In order to improve the degradation activity of β-glucosidase (CpBgl) from Coniophora puteana, the structural modification was conducted. The enzyme activity of mutants CpBgl-Q20C and CpBgl-A240S was increased by 65.75% and 58.58%, respectively. These mutants exhibited maximum activity under the same conditions as wild-type CpBgl (65 ℃ and pH 5.0), slightly improved stabilities compared that of the wild-type, and remarkably enhanced activities in the presence of Mn²⁺ or Fe²⁺. The V_max of CpBgl-Q20C and CpBgl-A240S was increased to 138.18 and 125.14 μmol/mg/min, respectively, from 81.34 μmol/mg/min of the wild-type, and the catalysis efficiency (k_cat/K_m) of CpBgl-Q20C (335.79 min^-1/mM) and CpBgl-A240S (281.51 min^-1/mM) was significantly improved compared with that of the wild-type (149.12 min^-1/mM). When the mutant CpBgl-Q20C were used in the practical degradation of different biomasses, the glucose yields of filter paper, corncob residue, and fungi mycelia residue were increased by 17.68%, 25.10%, and 20.37%, respectively. The spatial locations of the mutation residues in the architecture of CpBgl and their unique roles in the enzyme-substrate binding and catalytic efficiency were probed in this work. These results laid a foundation for evolution of other glycoside hydrolases and the industrial bio-degradation of cellulosic biomass in nature.

Current understanding of the inhibition factors and their mechanism of action for the lignocellulosic biomass hydrolysis

Biorefining of lignocellulosic biomass is a relatively new concept but it has strong potential to develop and partially replace the fossil derived fuels and myriad of value products to subsequently reduce the greenhouse gas emissions. However, the energy and cost intensive process of releasing the entrapped fermentable sugars is a major challenge for its commercialization. Various factors playing a detrimental role during enzymatic hydrolysis of biomass are inherent recalcitrance of lignocellulosic biomass, expensive enzymes, sub-optimal enzyme composition, lack of synergistic activity and enzyme inhibition caused by various inhibitors. The current study investigated the mechanism of enzyme inhibition during lignocellulosic biomass saccharification especially at high solid loadings. These inhibition factors are categorized into physio-chemical factors, water-soluble and -insoluble enzyme inhibitors, oligomers and enzyme-lignin binding. Furthermore, different approaches are proposed to alleviate the challenges and improve the enzymatic hydrolysis efficiency such as supplementation with surfactants, synergistic catalytic/non-catalytic proteins, and bioprocess modifications.

Large batch production of Galactooligosaccharides using β-glucosidase immobilized on chitosan-functionalized magnetic nanoparticle

β-glucosidase (BglA) immobilization from Thermotoga maritima on magnetic nanoparticles (MNPs) functionalized with chitosan (Cs) were efficiently investigated to improve lactose conversion and galactooligosaccharides (GOS) production. We used a batch method in order to improve the conversion of lactose to GOS. The efficiency and yield of immobilization were 79% and immobilized BglA was effectively recycled via a magnetic separation procedure through a batch-wise GOS with no activity lessening. Furthermore, analyses were done through screening kinetics of enzyme activity, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). Proposed methodology of immobilization shows a potential application as it is stable which was proved through many methods including pH, temperature, heat treatment, storage, and kinetics of the enzyme. GOS and residual enzyme activity showed to be 28.76 and 40.44%, respectively. However, free enzyme synthesis of GOS yield was just 24% after 12 hr. This study proposed applying magnet in the immobilization process of BglA on Cs-MNPs to produce GOS as new method for immobilizing enzyme in a biostable and cost-efficient way. PRACTICAL APPLICATIONS: This paper focus on immobilization of BglA from T. maritima onto MNPs functionalized with CS to investigate their further possibility improving lactose conversion and GOS production. Interestingly, a successful immobilization of Tm-BglA on the substrates were achieved in Cs-MNPs. The obtained results from enzyme activity, SDS-PAGE, FT-IR, and TEM showed that the high binding capacity of BglA to Cs-MNPs was successfully obtained. Furthermore, the binding efficiency calculation indicated that the immobilized BglA-Cs-MNPs conserved 40.44% of its native activity at the end of its 6th repeated use. In addition, magnetic separation technique was successfully employed for reuse of the immobilized BglA for repetitive batch-wise GOS without significant loss of activity.

Immobilization of β-Glucosidase from Thermatoga maritima on Chitin-functionalized Magnetic Nanoparticle via a Novel Thermostable Chitin-binding Domain

Enzyme immobilization is a powerful tool not only as a protective agent against harsh reaction conditions but also for the enhancement of enzyme activity, stability, reusability, and for the improvement of enzyme properties as well. Herein, immobilization of β-glucosidase from Thermotoga maritima (Tm-β-Glu) on magnetic nanoparticles (MNPs) functionalized with chitin (Ch) was investigated. This technology showed a novel thermostable chitin-binding domain (Tt-ChBD), which is more desirable in a wide range of large-scale applications. This exclusive approach was fabricated to improve the Galacto-oligosaccharide (GOS) production from a cheap and abundant by-product such as lactose through a novel green synthesis route. Additionally, SDS-PAGE, enzyme activity kinetics, transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR) revealed that among the immobilization strategies for Thermotoga maritime-β-Glucosidase thermostable chitin-binding domain (Tm-β-Glu-Tt-ChBD) on the attractive substrate; Ch-MNPs had the highest enzyme binding capacity and GOS production ratio when compared to the native enzyme. More interestingly, a magnetic separation technique was successfully employed in recycling the immobilized Tm-β-Glu for repetitive batch-wise GOS without significant loss or reduction of enzyme activity. This immobilization system displayed an operative stability status under various parameters, for instance, temperature, pH, thermal conditions, storage stabilities, and enzyme kinetics when compared with the native enzyme. Conclusively, the GOS yield and residual activity of the immobilized enzyme after the 10^th cycles were 31.23% and 66%, respectively. Whereas the GOS yield from native enzyme synthesis was just 25% after 12 h in the first batch. This study recommends applying Tt-ChBD in the immobilization process of Tm-β-Glu on Ch-MNPs to produce a low-cost GOS as a new eco-friendly process besides increasing the biostability and efficiency of the immobilized enzyme.