Chitosan production from Paecilomyces saturatus using three monosaccharides via mixture design

In this study, we demonstrate that chitosan is produced from Paecilomyces saturatus fungi using ternary monosaccharide carbon sources liquid cultivation via mixture design strategy. Sixteen experiments were carried out to obtain regression equations of fungal dry mycelial biomass (W), chitosan ratio (R), and deacetylation degree (DD) for plotting contour lines. Contour lines reveal that the maximum W, R, and DD can be simultaneously obtained in cultivated media containing 20% glucose, 60% fructose and 20% mannitol rather than pure monosaccharide cultivation. Three additional confirmation experiments based on the maximum FuCS deacetylation degree had been performed to confirm to be 92.3% via Fourier-transform infrared spectra. Accordingly, FuCS possessed much better anti-microbial activity on E. coli than commercial chitosan (CrCS). Meanwhile, X-ray diffraction results confirmed that FuCS possessed both α and γ crystalline peaks while CrCS possessed only α crystalline peak, being collaborated with thermogravimetric analysis results. The superior FuCS was obtained by using ternary monosaccharides system in fungal culture via mixture design for the first time. This study provides a new approach to produce chitosan from fungal cultivation by using the mixture design strategy. •Regression equations and contour plots were obtained via mixture design.•The optimal ternary monosaccharides medium reproducibility is confirmed with three repeating confirmation experiment.•Fungal chitosan possesses high deacetylation degree and superior antimicrobial activity.