Stabilization of an enzymatic extract from Penicillium camemberti containing lipoxygenase and hydroperoxide lyase activities

The stabilization of an enzymatic extract, obtained from Penicillium camemberti containing lipoxygenase (LOX) and hydroperoxide lyase (HPL) activities, was investigated using selected additives. Although the addition of KCI (86%, w/w) to the enzymatic extract decreased slightly (7%) the LOX activity, it increased HPL activity by 2.25 fold; however, the addition of dextran resulted in the inactivation of both enzymatic activities. The stability of the solid lyophilized enzymatic extract was greater in the presence of KCI than that without it, with similar to 100% residual activity after 8 and 4 weeks of storage at -80 degrees C, for LOX and HPL, respectively. The rate constants of inactivation (K-inactivation) and the C-(1/2) values showed that glycine was the most appropriate additive for LOX and HPL. All other investigated additives, including glycerol, polyethylene glycol, mannitol and sucrose, demonstrated a higher inactivation effect on both enzymatic activities. Although most of the investigated additives provided certain enhancement of the thermostability of LOX activity but not for HPL, a high thermostability (80 degrees C, 1 h) was obtained with 5% mannitol for LOX and 10% glycine for HPL. (C) 2007 Elsevier Ltd. All rights reserved.