ASPERGILLUS TERREUS IN SOLID STATE CULTURES

Abstract

Information of -xylanases has been increasingly forthcoming in recent years because of their possible involvement in numerous industrial processmg. Solid state fermentation (SSF) processes are more relevant to developing countries because of their technological simplicity and the ability to operate reasonably effectrvely tmder non-aseptic conditions. Solici substrates used in SSF are generally unrefined materials of agricultural origin. Lignocellulosic materials have the advantage ofbeing cheap since it is a major by-product of agriculture. Therefore, our present research aimed at optimizing culture conditions in order to achieve maximal xylanase activity by A. terreus in SSF. The enzyme produced showd promising characters in addition to its property in producing low cellulase activity. Our results are summarized as follows: 1. The potency of A. terreus to utilize different agroindustrial by-products as a sole carbon source and produce xylanase, was tested. Wheat straw, wheat bran, com cob, rice husk and barley spent grain were used as solid substrates in the fermentation. The utilization of wheat straw as C­ source and xylanase inducer was conductive to the highest enzyme activity. 2. Assessment studies were made to improve the xylanase yield by using pre-treated substrate; coarse grmmd (5mm), fine ground (2mm) autoclaved and delignified with NaOH or NaC102 . Highest enzyme activity and specific activity were obtained when finely ground wheat straw was used.