Exo-polygalacturonase production by Penicillium roqueforti on pumpkin oil cake in solid state fermentation

Abstract

The feasibility of using pumpkin oil cake (PuOC), individual and in combination with wheat bran (WB), as substrate for the production of Exo-polygalacturonase (Exo-p) by starter culture Penicillium roqueforti in solid state fermentation (SSF) has been evaluated The kinetics of enzyme production was investigated using PuOC alone in the range from 13 to 168 h, with moisture contents varvingfrom 44% the abilitv to grow and produce Exo-p activity on this substrate, reaching a maximum value of 1451.75 U/g.d.w PuOC by the 5th day of fermentation. Fermentation experiments indicated that the water activity (aw) influenced the enzyme production. A medium with aw 0.932 and the fermentation time of 5 days were selected, as these conditions resulted in the highest pectolytic activity and were usedfor further investigation. A next step in this research was to examine the effect of the substrate combination, PuOC with wheat bran (WB), in different ratios. The addition of WB as carbon sources was found to have a signiflicant influence on the enzymes yields. Exo-p activities were the highest with initial water activity of aw 0.932 and PuOC supplementation with WB (1:0.67).