Apple pomace as a substrate for fungal chitosan production in an airlift bioreactor

The aim of this work was to evaluate apple pomace as carbon source for fungal chitosan production in an external-loop airlift bioreactor by Gongronella butleri. Apple pomace has high moisture content, insoluble carbohydrates such as cellulose, hemicellulose and lignin, reducing sugars like glucose and fructose and other sugars such as sucrose. Due to its high content of sugars, apple pomace can be a potential substrate for fungal chitosan production. To improve chitosan production from apple pomace, the effect of the nitrogen sources NaNO3 and (NH4)2SO4 and specific aeration rate of 0.1, 0.3 and 0.6 vvm was investigated. The ammonium sulfate and specific aeration rate of 0.6 vvm had significant effect (p<0.05) and showed higher degree of deacetylation and chitosan concentration in the G. butleri biomass. Apple pomace seems to be a potential substrate for fungal chitosan production by G. butleri and its use can reduce the production cost of this biopolymer and reduce the environmental impact of this agro-industrial waste.