Modeling of polygalacturonasees(PGases) production using Aspergillus niger in a surface culture bioreactor

Pectinases are a group of hydrolytic enzymes that degrade pectic substances. They are produced by a variety of microorganisms including filamentous fungi. In this work the modeling of PGases production by Aspergillus niger was investigated in a surface culture bioreactor using pectin as the substrate. The fermentation started in batch mode until the medium was covered by the mycelia of the microorganism and after that it turned to continuous mode by introducing the fresh feed. The process continued for 34 days. The thickness of the microorganism layer on the surface of the liquid medium became almost constant after about one week. A Michaels-Menton type equation was considered for the rate of PGases production in the surface culture bioreactor, and the process was modeled. The model parameters were estimated using an optimization method (Particle Swarm Optimization). The model predicted the experimental data reasonably well.

Keywords:

Polygalacturonase , Aspergillus niger , Surface culture fermentation , continuous production , Modeling