Biocatalytic gelation of silica in the presence of a lipase

The effect of the lipase from Burkholderia cepacia ( previously known as Pseudomonas cepacia) on the gelation kinetics and gel structure was examined on a type of silica aerogel made from a mixture of methyltrimethoxysilane and tetramethoxysilane. For this purpose, gels were made with increasing concentrations of lipase in otherwise constant other conditions ( pH, water and Si precursors concentrations). It was found that the enzyme accelerated the gelation kinetics, hence was participating in some way to the hydrolysis of the silica precursor. The structure of the gel was simultaneously modified to produce an increasing proportion of Q(4) silicon sites.