(433h) Lipase Nanogel for Biodiesel Production

       We report here a two-step
procedure preparing lipase nanogel. The first step is to introduce vinyl groups
onto enzyme surface and the second step is in-situ polymerization using acrylamide
as monomers. The nanogel network, while enhancing the stability of encapsulated
enzyme via multiple covalent attachments, generates minor additional resistance
for mass transport. The greatly enhanced durability against harsh conditions,
e.g. high temperature and the presence of organic solvent, indicates a great
potential for industrial process of many kind.

       Lipase (EC 3.1.1.3) is extensively studied for
potential application in synthesis of surfactants and pharmaceuticals, production
of biodiesel, resolution of racemic mixtures, and detergent industry. The
production of biodiesel from plant oil can be efficiently catalyzed by lipase
in a water-containing system without an organic solvent. However, this process
is hindered by methanol induced deactivation of lipase.

       In this work, lipase
nanogel was prepared using above mentioned procedure. Transmission electron microscope
(TEM), size exclusion chromatography (SEC), SDS-PAGE, FT-IR were used to
characterize the enzyme nanogel. Using p-Nitrophenylburate as substrate, Km and
Vmax of lipase nanogel was 0.29 mM, 51 Umg-1 while their respective counterpart
of free lipase was 0.28 mM, 87 Umg-1. The half-life time of native lipase was
50 min at 50°C while almost no visible loss
of lipase activity was observed in the 500 min for the nanogel. After
incubation in 40% methanol aqueous solution, lipase nanogel preserved about 80%
of its hydrolytic activity while native lipase reserved only 10%. All these are
of great interest for further exploration of the potential application of
lipase nanogel for the production of biodiesel.