The purification of a lipase isoenzyme from an Aspergillus niger lipase A is reported in this manuscript.
Purification was carried out in a simple adsorption step, in which the lipase
was offered at low ionic strength to the commercially available C8 modified
magnetic particles, MaKProt C8. When the isoenzyme was desorbed with a 0.2%
solution of Triton X-100, the SDS-PAGE gel showed a single pure band with a
molecular weight of 35 KDa. The purified fraction showed 66.75-fold purification
compared with the crude extract. The pure fraction was characterized along with
the crude extract and the lipase adsorbed on the MaKProt C8. The purified and
the adsorbed lipase showed better activity for the tested substrates
(p-nitrophenyl acetate, decanoate, myristate and palmitate) than the crude extract, the preferred substrates being myristate
(26.7 μmol·min-1·mg-1) and decanoate (17.4 μmol·min-1·mg-1),
respectively. The temperature and pH profiles showed no change for the three
enzymes, the optimum temperature being 37°C and the best pH 7.0.