Role of Anionic Polysaccharide (Alginate) on Activity, Stability and Recycling Efficiency of Bacterial Endo (1→4) β-d-Glucanase of GH12 Family

Biochemical characterization of immobilized recombinant subtilisin and synthesis and functional characterization of recombinant subtilisin capped silver and zinc oxide nanoparticles

This pioneering research explores the transformative potential of recombinant subtilisin, emphasizing its strategic immobilization and nanoparticle synthesis to elevate both stability and therapeutic efficacy. Achieving an impressive 95.25 % immobilization yield with 3 % alginate composed of sodium along with 0.2 M CaCl2 indicates heightened pH levels and thermal resistance, with optimal action around pH 10 as well as 80 °C temperature. Notably, the Ca-alginate-immobilized subtilisin exhibits exceptional storage longevity and recyclability, affirming its practical viability. Comprehensive analyses of the recombinant subtilisin under diverse conditions underscore its adaptability, reflected in kinetic enhancements with increased Vmax (10.7 ± 15 × 103 U/mg) and decreased Km (0.19 ± 0.3 mM) values post-immobilization using N-Suc-F-A-A-F-pNA. UV-visible spectroscopy confirms the successful capping of nanoparticles made of Ag and ZnO by recombinant subtilisin, imparting profound antibacterial efficacy against diverse organisms and compelling antioxidant properties. Cytotoxicity was detected against the MCF-7 breast cancer line of cells, exhibiting IC50 concentrations at 8.87 as well as 14.52 µg/mL of AgNP as well as ZnONP, correspondingly, indicating promising anticancer potential. Rigorous characterization, including FTIR, SEM-EDS, TGA and AFM robustly validate the properties of the capped nanoparticles. Beyond therapeutic implications, the investigation explores industrial applications, revealing the versatility of recombinant subtilisin in dehairing, blood clot dissolution, biosurfactant activity, and blood stain removal. In summary, this research unfolds the exceptional promise of recombinant subtilisin and its nanoparticles, presenting compelling opportunities for diverse therapeutic applications in medicine. These findings contribute substantively to biotechnology and healthcare and stimulate avenues for further innovation and exploration.

Characterization of the Biomass Degrading Enzyme GuxA from Acidothermus cellulolyticus

Microbial conversion of biomass relies on a complex combination of enzyme systems promoting synergy to overcome biomass recalcitrance. Some thermophilic bacteria have been shown to exhibit particularly high levels of cellulolytic activity, making them of particular interest for biomass conversion. These bacteria use varying combinations of CAZymes that vary in complexity from a single catalytic domain to large multi-modular and multi-functional architectures to deconstruct biomass. Since the discovery of CelA from Caldicellulosiruptor bescii which was identified as one of the most active cellulase so far identified, the search for efficient multi-modular and multi-functional CAZymes has intensified. One of these candidates, GuxA (previously Acel_0615), was recently shown to exhibit synergy with other CAZymes in C. bescii, leading to a dramatic increase in growth on biomass when expressed in this host. GuxA is a multi-modular and multi-functional enzyme from Acidothermus cellulolyticus whose catalytic domains include a xylanase/endoglucanase GH12 and an exoglucanase GH6, representing a unique combination of these two glycoside hydrolase families in a single CAZyme. These attributes make GuxA of particular interest as a potential candidate for thermophilic industrial enzyme preparations. Here, we present a more complete characterization of GuxA to understand the mechanism of its activity and substrate specificity. In addition, we demonstrate that GuxA exhibits high levels of synergism with E1, a companion endoglucanase from A. cellulolyticus. We also present a crystal structure of one of the GuxA domains and dissect the structural features that might contribute to its thermotolerance.

Thermodynamics, kinetics and optimization of catalytic behavior of polyacrylamide-entrapped carboxymethyl cellulase (CMCase) for prospective industrial use

In the current study, kinetic and thermodynamic parameters of free and polyacrylamide-immobilized CMCase were analyzed. The maximum immobilization yield of 34 ± 1.7% was achieved at 11% acrylamide. The enthalpy of activation (ΔH) of free and immobilized enzyme was found to be 13.61 and 0.29 kJ mol^-1, respectively. Irreversible inactivation energy of free and immobilized CMCase was 96.43 and 99.01 kJ mol^-1, respectively. Similarly, the enthalpy of deactivation (ΔH_d) values for free and immobilized enzyme were found to be in the range of 93.51-93.76 kJ mol^-1 and 96.08-96.33 kJ mol^-1, respectively. Michaelis-Menten constant (K_m) increased from 1.267 ± 0.06 to 1.5891 ± 0.07 mg ml^-1 and the maximum reaction rate (V_max) value decreased (8319.47 ± 416 to 5643.34 ± 282 U ml^-1 min^-1) after immobilization. Due to wide pH and temperature stability profile with sufficient reusing efficiency up to three successive cycles, the immobilized CMCase might be useful for various industrial processes.

Single step immobilization of CMCase within agarose gel matrix: Kinetics and thermodynamic studies

In the current study, CMCase from Bacillus licheniformis KIBGE-IB2 was immobilized within the matrix of agarose gel through entrapment technique. Maximum immobilization yield (%) of the enzyme was obtained when 2.0 % agarose was used. The activation energy (E_a) of the enzyme increased from 16.38 to 44.08 kJ mol^-1 after immobilization. Thermodynamic parameters such as activation energy of deactivation (ΔG_d), enthalpy (ΔH_d) and entropy (ΔS_d) of deactivation, deactivation rate constant (K_d), half-life (t_1/2), D-value and z-value were calculated for native/free and immobilized CMCase. The maximum reaction rate (V_max) of the native enzyme was found to be 8319.47 U ml^-1 min^-1, which reduced to 7218.1 U ml^-1 min^-1after immobilization process. However, the Michaelis-Menten constant (K_m) value of the enzyme increased from 1.236 to 2.769 mg ml^-1 min^-1 after immobilization. Immobilized enzyme within agarose gel matrix support can be reuse up to eight reaction cycles. Broad stability profile and improved catalytic properties of the immobilized CMCase indicated that this enzyme can be a plausible candidate to be used in various industrial processes.

Immobilization of Dextranase Using Anionic Natural Polymer Alginate as a Matrix for the Degradation of a Long-Chain Biopolymer (Dextran)

Alginate is an inexpensive, nontoxic, valuable biopolymer utilized in the study for the immobilization of commercially applicable biocatalyst dextranase. Dextranase was immobilized by an entrapment method, and alginate hydrogel spheres were synthesized after optimizing several parameters. A sodium alginate concentration of 4.0% was noticed to be suitable along with a calcium chloride concentration of 0.2 molar after providing a curing time of 20 minutes. After comparing the characteristics of the entrapped enzyme with those of the soluble one, it was observed that the characteristics were more or less the same except for the change in reaction time which was noticed to be prolonged in the case of entrapped dextranase while the change in temperature and pH optima was not observed. The variation in Vmax and Km values of dextranase after entrapment was also noted. However, after extensive stability examination studies, it was found that dextranase became more stable after entrapment; as a result, it retained more than 50% of its original activity at elevated temperature even after exposure for about 2.0 hours. The reusability of dextranase was up to 7.0 cycles after performing catalytic activity under constant condition.