Covalent immobilization of Candida antarctica lipase B on nanopolystyrene and its application to microwave-assisted esterification

Abstract

Nanopolystyrene was used as a solid support for the covalent immobilization of Candida antarctica lipase B (CalB) using the photoreactive reagent 1-fluoro-2-nitro-4-azido benzene (FNAB) as a coupling reagent. The obtained derivative was then used as a biocatalyst in a microwave assisted esterification experiment. Factors such as contact time, pH, and enzyme concentration were investigated during immobilization. The hydrolytic activity, thermal, and operational stability of immobilized-CalB were determined. The maximum immobilized yield (218 µg/mg support) obtained at pH 6.8 exhibited optimum hydrolytic activity (4.42 × 10 3 mU p-nitrophenol/min). The thermal stability of CalB improved significantly when it was immobilized at pH 10, however, the immobilized yield was very low (93.6 µg/mg support). The immobilized-CalB prepared at pH 6.8 and pH 10 retained 50% of its initial activity after incubation periods of 14 and 16 h, respectively, at 60 °C. The operational stability was investigated for the microwave assisted esterification of oleic acid with methanol. Immobilized-CalB retained 50% of its initial activity after 15 batch cycles in the microwave-assisted esterification. The esterification time was notably reduced under microwave irradiation. The combined use of a biocatalyst and microwave heating is thus an alternative total green synthesis process.

Biotic and Abiotic Synthesis of Renewable Aliphatic Polyesters from Short Building Blocks Obtained from Biotechnology

“…[261] As an example, the esterification of oleic acid by methanolc atalyzed by immobilizedC ALB in the bulk did not show any improvements under microwave irradiation. [262] On the contrary,t he transesterification of b-ketoesters by N435 under microwave irradiationi ns olvent-free conditions gave good results. [263] Due to these mixed results, until now,o nly a limitedn umber of studies have been performed on polyester synthesis.…”

Enzymatic Synthesis of Polycaprolactone: Effect of Immobilization Mechanism of CALB on Polycaprolactone Synthesis

“…The commercially available CALB, Novozyme ® 435, is physically adsorbed on a macroporous acrylic polymer resin [4] and is used for ring opening polymerization of several lactones. Even though it has many advantages in polymer synthesis, there are some major problems of utilization of Novozyme 435: High cost, leaching problem of the enzyme and diffusional limitations [5]. Rice husk ash (RHA) is a light and highly porous material with high silica content which has emerged as a cheap alternative to fumed silica [6].…”

Tailoring the Spacer Arm for Covalent Immobilization of Candida antarctica Lipase B—Thermal Stabilization by Bisepoxide-Activated Aminoalkyl Resins in Continuous-Flow Reactors

“…Immobilization of enzymes is a powerful biochemical tool with a potential for improving enzyme activity, temperature stability, and selectivity [23]. Retaining the active conformation during immobilization is very important for enzyme activity [24]; therefore, finding an immobilization protocol that increases enzyme activity and stability should be a target of real importance [25]. Several immobilization techniques are available for protein immobilization: adsorption, covalent attachment onto solid supports, cross-linking and entrapment of protein in matrices.…”