Abstract

Skim latex from Hevea brasiliensis (rubber tree) contains many useful enzymes that can be utilized to produce value-added products. Lipase recovered from skim latex serum was immobilized via cross-linked enzyme aggregates (CLEA) technology, while supported by magnetic nanoparticles termed ‘MNP-CLEA-lipase’. One of the main advantages of this method is, the biocatalyst can be easily recovered by a magnetic field for recycling. In this research, dialdehydic pectin was used as the cross-linking agent, replacing glutaraldehyde, and soy protein was used as an additive, replacing bovine serum albumin (BSA). The operating conditions for the preparation of the most active MNP-CLEA- lipase were optimized statistically. Dialdehydic pectin and soy protein showed optimum operating conditions at 180 mg/mL and 0.6% (w/v) respectively and with (NH4 )2 SO4 at 80% saturation, giving a Residual Activity (RA) of 154%. The optimum temperature for MNP-CLEA-lipase was at 40°C (127% RA) while the optimum pH was at 8 (127% RA). It retained 20% RA after 100 days of storage. The reusability test showed that it maintained 7% RA after the 10th cycle. This research showed two advantages; first, that value-added products can be recovered from agricultural waste, and second, by alternating to low-cost food-grade cross-linkers and additives, enhanced biocatalyst can be produced which can be safely used in the beverage and food industries.

Keywords

MNP-CLEA-lipase, Hevea brasiliensis, cross-linked enzyme aggregates (CLEA), macromolecular cross-linker, glutaraldehyde, pectin, soy protein