Effect of additives on transesterification activity of Rhizopus chinensis lipase

The transesterification activity of powder lipase prepared from the purifie d lipase of Rhizopus chinensis cells by freeze-drying was quite low compare d with that of acetone-dried cells. Additives which could enhance the trans esterification activity of the freeze-dried powder lipase were screened. Th e freeze-dried lipases prepared with certain fatty acid methylesters or cer tain types of surfactants exhibited high transesterification activity. It w as shown that not only the solubility of the freeze-dried Lipase in n-hexan e but also the organic solvent-stability was enhanced when methyl stearate was added to the lipase solution at the freeze-drying step.