Application of Plackett-Burman design for the optimization of protease production by Aspergillus niger

Abstract

Proteolytic enzymes represent one of the largest groups of industrial enzymes. Fungal proteases have been used for the large-scale production of industrial enzymes. The optimization of enzyme production is a very important objective, where the aim is to further improve the production process. Therefore, the application of an experimental statistical method is essential. In this study, the production of the enzyme protease was carried out by fermentation of a mold (Aspergillus niger) using two media, one based on wheat bran and the other based on peas chick. The optimization of the synthesis of the enzyme was carried out using a statistical method of experimental planning based on the Plackett and Burman matrices. The variables used are the 3 production factors temperature, pH, and substrate concentration. The results were modeled according to multiple linear regression. The results obtained revealed that the strain A.niger gave an excellent activity reaching 740 IU for the wheat bran medium and 194.54 IU for the chickpea medium. The study of pH optima and incubation temperature has shown that the protease produced by A. niger has an optimum pH equal to 6 and an optimum temperature of 40°C for wheat bran medium and has an optimum pH equal to 5 and an optimum temperature of 30°C for chickpeas. The results obtained from the experimental designs of Plackett and Burman proved to be ideal for the selection of factors influencing protease production.