Immobilized Aspergillus niger Lipase with SiO2 Nanoparticles in Sol-Gel Materials

Abstract

Lipase from Aspergillus niger was "doubly immobilized" with SiO 2 nanoparticles in sol-gel powders prepared via the base-catalyzed polymerization of tetramethoxysilane (TMOS) and methyltreimethoxysilane (MTMS). The hydrolytic activity of the immobilized lipase was measured using the p-nitrophenyl palmitate hydrolysis method. The results showed that the optimum preparation conditions for the gels were made using a MTMS/TMOS molar ratio of 5, 60 mg of SiO 2 nanoparticles, a water/silane molar ratio of 12, 120 mg of enzyme supply, and 120 µL of PEG400. Under the optimal conditions, the immobilized lipase retained 92% of the loading protein and 94% of the total enzyme activity. Characteristic tests indicated that the immobilized lipase exhibited much higher thermal and pH stability than its free form, which shows great potential for industrial applications.

Chitosan–Collagen Coated Magnetic Nanoparticles for Lipase Immobilization—New Type of “Enzyme Friendly” Polymer Shell Crosslinking with Squaric Acid

“…Moreover, the separation of enzyme after reaction is somewhat complicated and needs centrifugation and precipitation. One of the most promising methods to improve the enzyme's disadvantages is immobilization [7,8]. The strategy of immobilization has a great impact on the attached enzyme properties-it may improve enzyme activity, stability, selectivity, and specificity [9,10].…”

“…The strategy of immobilization has a great impact on the attached enzyme properties-it may improve enzyme activity, stability, selectivity, and specificity [9,10]. In general, disadvantages is immobilization [7,8]. The strategy of immobilization has a great impact on the attached enzyme properties-it may improve enzyme activity, stability, selectivity, and specificity [9,10].…”

Improved Catalytic Performance of Lipase Supported on Clay/Chitosan Composite Beads

“…The mixture of supernatant and washing solution was collected, to determine the protein un-immobilized onto the beads by the Bradford method [25]. The amount of lipase protein immobilized onto the beads was determined by comparing the difference between the total amount of protein and the amount of protein in the mixture of supernatant and washing solution, as done in previous studies [5,8,13,18]. In addition, the immobilization yield of lipase on each kind of bead vs. time was also investigated at each optimum pH.…”

“…However, lipase used in its free form is very sensitive to heat and pH variation, and it is hard to separate free lipase from the reaction medium to be reused for continuous cycles [4,5]. To overcome these problems, lipase has been immobilized onto various natural and synthetic carriers to maintain its activity and stability [6][7][8][9]. Compared with synthetic matrix [10,11], natural materials are more eco-friendly and compatible with lipase molecules, contributing to good catalytic performance of immobilized lipase [12,13].…”

Immobilization of Thermostable Lipase QLM on Core-Shell Structured Polydopamine-Coated Fe3O4 Nanoparticles

“…Lipases (triacylglycerol acylhydrolase, EC 3.1.1.3) are a group of enzymes capable of catalyzing ester hydrolysis, esterification and transesterification reactions, which makes them promising biocatalysts in the food, pharmaceutical, detergent, and bioenergy industries [1][2][3]. However, they did not fulfill all the requirements of industrial biocatalysts, such as unsatisfactory stability against thermal, organic solvents, detergents, or metal ions and unfavorable recyclability [4,5].…”