Key parameters optimization of chitosan production from Aspergillus terreus using apple waste extract as sole carbon source.

Chitosan is commonly obtained from shrimp and crab shell chitin by deacetylation; however, such supplies appear limitation. An alternative source of chitosan is cell wall in certain fungi. In this study, chitosan production through submerged fermentation of Aspergillus terreus on apple waste extract as sole carbon source was investigated. Monod equation with a maximum specific growth rate of 0.083 h-1 and half-saturation constant of 6.67 w/v% was best described the kinetic of growth. Results of response surface methodology showed the highest chitosan to substrate yield of 49.32 mg gsubstrate-1, chitosan to fungal biomass yield of 140.9 mg gcell-1, and fungal biomass to substrate yield of 0.387 gcell gsubstrate-1 were simultaneously obtained at temperature 30.0 °C, initial pH 5.98, and ammonium nitrate concentration 5.0 g L-1. The chitosan produced at the optimum condition was characterized by FTIR, TGA, and DSC analysis, and degree of deacetylation was 88.2%.