Statistical Modeling and Optimization of Chitosan Production from Absidia coerulea Using Response Surface Methodology

Ahmed      ElMekawy; Ashraf   F.   El-Baz; Emad   A.   Soliman; Samuel      Hudson

Abstract

Optimization of chitosan production from Absidia coerulea mycelia was presented through a three-level full factorial design in terms of nitrogen source, glucose concentration, incubation time and temperature. The four factors, individually or interacted, had significant effects (95%) on chitosan production. The highest chitosan content (0.1829 g/l) was obtained after 72 h at 32°C using a medium containing ammonium sulfate (14 g/l) and glucose (20 g/l). Chitosan production was further optimized to improve yield using the response surface methodology. Various second order quadratic models were generated for each nitrogen source with respect to the other studied growth conditions. Subsequently, the optimum chitosan production factors were scaled up in a bioreactor. The maximum dry cell weight was nearly doubled on comparing the propagation in the shake flask level (7.841 g/l) against the bioreactor level (13.87 g/l), as well the incubation time was reduced from 72 h to 48 h.

Keywords: Fungal chitosan, Absidia coerulea, fermentation, response surface, bioreactor, full factorial, FT-IR, shaking flasks, modeling, alkali insoluble material, polydispersity, sodium nitrate, ammonium sulfate, YPG medium, least significant difference.