Use of Palm Kernel Meal as a Substrate for Mannanase Production Aspergillus wentii aud Its Optimized Condition Study During Solid StateFermentation

摘要

Aspergillus wentii was used to produce marmanase in a laboratory scale solid state fermentation (SSF) using palm kernel meal (PKM) as a subatrate. Results indicated that A. wentii secreted mannanase when grown on PKM as an impure inducer without any nutrient supplementation. The highest mannanase activity was obtained at 87 Ug~(-1). The optimum conditions were obtained at 40 % initial moisture content, 30 deg C, 2.5 % v/w of inoculum with 1x10~7 spores ml~(-1) using 1-1.5 cm medium thickness. The changes of water activity (aw) which closely related to the moisture content of the koji indicated that the suitable moisture level for the mannanase production was 40-50 % with the aw of 0.956-0.975. Results also found the low concomitantly cellulase andxylanase during mannanase were produced. Fermented PKM not only contained mannanase but also increased crude protein content by 12.9 % gDW from initial content and also the reducing sugars. These results revealed that PKM is an inexpensive and potentialsubstrate for mannanase production by A. wentii.