Improved enzymatic performance of graphene-immobilized β-glucosidase A in the presence of glucose-6-phosphate

Smart sustainable biorefineries for lignocellulosic biomass

Lignocellulosic biomass (LCB) is considered as a sustainable feedstock for a biorefinery to generate biofuels and other bio-chemicals. However, commercialization is one of the challenges that limits cost-effective operation of conventional LCB biorefinery. This article highlights some studies on the sustainability of LCB in terms of cost-competitiveness and environmental impact reduction. In addition, the development of computational intelligence methods such as Artificial Intelligence (AI) as a tool to aid the improvement of LCB biorefinery in terms of optimization, prediction, classification, and decision support systems. Lastly, this review examines the possible research gaps on the production and valorization in a smart sustainable biorefinery towards circular economy.

Application of lipase immobilized on a hydrophobic support for the synthesis of aromatic esters

The present study aimed at preparing three biocatalysts via physical adsorption of lipases from Candida rugosa (CRL), Mucor javanicus, and Candida sp. on a hydrophobic and mesoporous support (Diaion HP-20). These biocatalysts were later applied to the synthesis of aromatic esters of apple peel and citrus (hexyl butyrate), apple and rose (geranyl butyrate), and apricot and pineapple (propyl butyrate). Scanning electron microscopy and gel electrophoresis confirmed a selective adsorption of lipases on Diaion, thus endorsing simultaneous immobilization and purification. Gibbs free energy (∆G) evinced the spontaneity of the process (-17.9 kJ/mol ≤ ∆G ≤ -5.1 kJ/mol). Maximum immobilized protein concentration of 30 mg/g support by CRL. This biocatalyst was the most active in olive oil hydrolysis (hydrolytic activity of 126.0 ± 2.0 U/g) and in the synthesis of aromatic esters. Maximum conversion yield of 89.1% was attained after 150 Min for the synthesis of hexyl butyrate, followed by the synthesis of geranyl butyrate (87.3% after 240 Min) and propyl butyrate (80.0% after 150 Min). CRL immobilized on Diaion retained around 93% of its original activity after six consecutive cycles of 150 Min for the synthesis of hexyl butyrate.

A novel strategy to synthesize dual-responsive polymeric nanocarriers for investigating the activity and stability of immobilized pectinase

A dual-stimuli-responsive support material for pectinase immobilization through ionic bonding was prepared. Specifically, polystyrene-b-polymethylacrylic (PS-b-PMAA), light- and pH-sensitive polystyrene-(5-propargylether-2-nitrobenzyl bromoisobutyrate)-b-poly(diethylamino)ethyl methacrylate-b-poly(polyethylene glycol methacrylate) (PS-ONB-PDEAEMA-b-PPEGMA) were synthesized through atom transfer radical polymerization, click chemistry, and hydrolysis. The two parts could self-assemble into the micelles in an aqueous solution. The micelles shrunk at a higher pH, and their size reduced under UV irradiation. The stimuli-responsive properties of micelles were characterized by dynamic light scattering and transmission electron microscopy. It has been found that this support was able to adsorb 10 U/mL of immobilized pectinase (approximately 223 mg/g) at pH 5.0 and 60 °C for 60 Min. Meanwhile, the highest relative activity of immobilized pectinase was up to approximately 95% at pH 5.0 and 60 °C. The immobilized pectinase retained more than 50% of the initial activity after eight cycles. The relative activity of the pectinase immobilized on the supports without UV irradiation was approximately 3% lower than that after UV irradiation at 60 °C, indicating that tailoring of enzyme activity was achieved by changing environmental conditions. Apparently, the original enzymatic support material had a great application prospect on enzyme immobilization.