Temperature controlled activity of lipase B from Candida Antarctica after immobilization within p-NIPAM microgel particles

The immobilization of lipase B from Candida antarctica (CalB) within micronsized poly-NIsopropylacrylamide (p-NIPAM) microgel particles with a crosslinker content of 5% is reported. The immobilization of the enzyme was reached by an exchange from polar to organic solvents. After determining the embedded amount of CalB within the polymer network, an enhanced specific activity in n-hexane was obtained. Due to the thermoresponsibility of the polymer particles, the activity reaction was done at 25 °C and 50 °C. The results presented show that the reversible collapse of the microgel leads to a decreased activity with increasing temperature. Hence, p-NIPAM microgels display a good opportunity to tailor the activity of CalB. An interesting side effect is that CalB presents a suitable probe to estimate the mesh size of the polymer network, since it penetrates in the unlabeled form but not after labeling with FITC.