High reusability of lipase immobilised on eggshells for butyl butyrate synthesis under optimum condition

Abstract

Eggshells capacity as supporting material for immobilisation of Candida rugosa Type VII lipase (CRL) was tested. Different parameters for the immobilisation of eggshells were studied including the temperature (30-50°C), pH of buffer the solution (pH 5-8), particle size of the eggshells (≤1mm, 1-2mm and 2-4mm), immobilisation time (1-4 hr) and glutaraldehyde concentration (0.30-3.00%, v/v). The best immobilisation conditions obtained were ≤1mm size of the eggshells added with 0.75% of glutaraldehyde at pH buffer 6. The immobilisation time taken was 3 hr at 50°C. Then optimal conditions for the ester synthesis of butyl butyrate were achieved using 2.0g of the immobilised lipase loading that reacted at 30°C using a 0.2 molar ratio of the substrate for 3 hr. Under optimal conditions (immobilization and esterification), 93.3% of conversion yield of butyl butyrate was obtained. Furthermore, the synthesized immobilised CRL lipase demonstrate that it was highly reusable as it retained 50% of the initial activity after 31 cycles.