Kinetics and mechanism of regioselective monoacetylation of 3-aryloxy-1,2-propandiols using immobilized Candida antarctica lipase

Immobilized Candida antarctica lipase B catalyzed synthesis of biodegradable polymers for biomedical applications

Biomedical applications of biodegradable polymers synthesized via the catalysis of immobilized Candida antarctica lipase B (CALB).

Acoustic cavitation promoted lipase catalysed synthesis of isobutyl propionate in solvent free system: Optimization and kinetic studies

The present work highlights the effect of ultrasound on enzymatic synthesis of isobutyl propionate, a rum flavor by esterification of isobutanol and propionic acid in non-aqueous, solvent free system (SFS) using Fermase CALB™10000. The optimization study for different variables in presence of ultrasound showed a maximum conversion of 95.14% at 60°C temperature, 4% w/w enzyme dose, 1:3 acid:alcohol ratio, 40W power, 25kHz frequency, 50% duty cycle and 150rpm speed in 3h as compared to 10h of conventional method. The optimal enzyme loading was reduced to 4% w/w using ultrasound irradiation compared to 5% w/w of conventional. The efficiency of enzyme improved notably and can be reused up to seven cycles preserving its former activity. The application of ultrasound greatly enhanced esterification reactions by maintaining enzyme stability and improving the production yield. Moreover, owing towards a green approach, the synthesis is carried out in SFS for development of lucrative flavor ester. Bisubstrate kinetic models like random bi-bi, ping pong bi-bi and ordered bi-bi were applied to the experimental data using non-linear regression analysis. The experimental data and kinetic study revealed that reaction obeyed Ping-Pong bi-bi model with kinetic parameters, V_max=50.0M/min/gcatalyst, K_A=4.87×10^-2M, K_B=9.06×10^-4M, K_iA=9.8×10^-1M, K_iB=1.05×10^-3M &SSE=2.74×10^-4 for lipase catalysed synthesis of isobutyl propionate under ultrasound with inhibition by both acid and alcohol.

Biocatalytic synthesis of vitamin A palmitate using immobilized lipase produced by recombinant Pichia pastoris

In this work, the Candida antarctica lipase B (CALB), produced by recombinant Pichia pastoris, was immobilized and used to synthesize vitamin A palmitate by transesterification of vitamin A acetate and palmitic acid in organic solvent. The reaction conditions including the type of solvent, temperature, rotation speed, particle size, and molar ratio between the two substrates were investigated. It turned out that the macroporous resin HPD826 serving as a carrier showed the highest activity (ca. 9200 U g^-1) among all the screened carriers. It was found that the transesterification kinetic of the immobilized CALB followed the ping pong Bi-Bi mechanism and the reaction product acetic acid inhibited the enzymatic reaction with an inhibition factor of 2.823 mmol L^-1. The conversion ability of the immobilized CALB was 54.3% after 15 cycles. In conclusion, the present work provides a green route for vitamin A palmitate production using immobilized CALB to catalyze the transesterification of vitamin A acetate and palmitic acid.