ARTICLE; PHARMACEUTICAL BIOTECHNOLOGY Solgel immobilization as a suitable technique for enhancement of a-amylase activity of Aspergillus oryzae PP

Bioencapsulation of microbial cells in silica-based matrices has proved to be a good strategy to enhance the biosynthetic capabilities and viability of bioproducers. In the present study, mycelium and pellet cultures of strain Aspergillus oryzae PP were successfully immobilized in solgel hybrid matrices composed of tetraethylorthosilicate as an inorganic precursor, 5 % (w/v) starch and 10 or 15 % (w/v) polyethylene oxide, or 10 % (w/v) calcium alginate as organic compounds. Biosynthetic activity of immobilized cultures was investigated by batch and fed-batch cultivation and the obtained results of 3042.04 IU cm¡3 were comparable with the enzyme activity of the free cell culture. Immobilized cultures retained their viability and biosynthetic capabilities up to the 744th h during fed-batch fermentation processes. Consequently, solgel encapsulation in hybrid matrices could be considered as a promising technique for immobilization of Aspergillus oryzae PP in order to increase the a-amylase production