Multiresponse analysis of microbiological parameters affecting the production of pectolytic enzymes by Aspergillus niger: a statistical view

The effect of microbiological parameters, viz,, slant age, inoculum age and amount of inoculum were studied using response surface methodology for the production of pectolytic enzymes, polymethylgalacturonase, polygalacturona se and pectinlyase. The central composite design was used to determine the individual optimum values. Individual optimum values of slant age, inoculum age and amount of inoculum were 49.5 h, 52.3 h and 11.2%, respectively, fo r polymethylgalacturonase; 62.4 h, 60.5 h and 14.4%, respectively. for poly galacturonase, and 78.3 h, 52.5 h and 13.4%, respectively, for pectinlyase. In order to develop a two-stage inoculum possessing the best conditions fo r the maximum production of all three enzymes, a multiresponse analysis was carried out using a generalized distance approach. The microbiological par ameters were optimized simultaneously for maximum production of enzymes. Th e simultaneous optimal values of slant age. inoculum age and amount of inoc ulum were 81.4 h, 66.7 h and 15.8%, respectively, for all the three enzymes . After optimization, the fermentation time was reduced from 144 to 120 h. (C) 1998 Elsevier Science Ltd. All rights reserved.