SiO2 Xerogel: A Suitable Inert Support for Microbial Growth

A silica xerogel was prepared at pH 2 by the hydrolysis-condensation reactions of the sol-gel method. Silica xerogel was used as a support for the growth of two filamentous fungi: Aspergillus niger ATCC 9642 and Phanerochaete chrysosporium A594. In both cases, an apparent abundant mycelia growth (5.5 mg biomass/g dry xerogel and 4.7 mg biomass/g dry xerogel respectively) was observed. A phase of rapid consumption of glucose which lasted until 96 h of culture with sugar consumption rate of 0.075 mg sugar/g support h and 0.042 mg sugar/g support h respectively, was also observed. Scanning electron microscopy (SEM) showed a superficial colonisation of both strains even in the occasional imperfections and crevices of the xerogel. This novel application of sol-gel metallic oxide systems suggests the potential use of an inert and versatile support which could be valuable, for example for solid state fermentation fundamental studies.