Fungal chitosan production using xylose rich of corn stover prehydrolysate by Rhizopus oryzae

Abstract

Xylose rich of lignocellulosic prehydrolysate could be used for fungal chitosan production effectively by Rhizopus oryzae. When 15 g/L xylose was used as carbon source for R. oryzae AS 3.819 fermentation, almost all of the xylose was consumed for cell growth (4.33 g/L of biomass) and the chitosan extraction yield was 0.11 g/g biomass. Corn stover prehydrolysate by dilute acid-assisted steam explosion pretreatment that contained 30 g/L xylose and 10 g/L glucose was fermented by R. oryzae AS 3.819 for 72 h, the biomass and the chitosan extraction yield were 10.96 g/L and 0.09 g/g biomass. The degree of deacetylation of the fungal chitosan derived from corn stover prehydrolysate (91.27%) was higher than that of the commercial chitosan extracted from natural shellfish exoskeleton (87.25%), and the viscosity of the fungal chitosan derived from corn stover prehydrolysate (2.67 mPa⋅s) had a large decrease compared to the commercial chitosan (22.25 mPa⋅s). The functional groups and thermostability of the fungal chitosan were proofed by Infrared (IR) spectra and Derivative thermogravimetric (DTG), respectively.

Keywords

• Rhizopus oryzae
• fungal chitosan
• lignocellulosic prehydrolysate
• xylose