Effects of organic solvents on activity and conformation of recombinant Candida antarctica lipase A produced by Pichia pastoris

► The catalytic activity of CALA increased after treatment with acetonitrile or acetone. ► The variance of catalytic activity mainly attributed to the secondary structure changes. ► The acetonitrile treatment could increase the thermal and pH stability of CALA. The effect of various organic solvents on the hydrolytic and esterification activities of lipase A from Candida antarctica (CALA) was investigated. Compared to the control group, the esterification and hydrolytic activities of CALA both increased with treatment of acetonitrile or acetone. However, the catalytic activity decreased after treatment with other organic solvents, especially with ethanol or ethyl acetate. Moreover, with treatment by the same organic solvents, the residual esterification activity of CALA was much higher than the hydrolytic activity for the olive oil. Results of Fourier transform-infrared spectroscopy analysis implied that the catalytic activity variance was mainly attributed to the secondary structure changes of CALA. The acetonitrile treatment could also increase the thermal and pH stability of CALA.