This study was carried out to isolate chitosan producing fungi from different food sources. Forty five isolates of fungi were isolated from different natural contaminated sources, Twenty three isolates belonging to genus Aspergillus while. The other twenty two isolates were belonging to genus Rhizopus. All isolates were tested to choose the potential isolates according to the yield of fungal biomass. Results showed that, Aspergillus isolates gave an amount of biomass yield more than that obtained by Rhizopus isolates grown on all the tested media. The obtained results is clearly indicate that the highest records of fresh and dry weights of Aspergillus biomass were obtained on Karimi's medium while, the highest records of fresh and dry weights of Rhizopus biomass were observed on yeast peptone glucose medium. The selected fungal isolates which produced considerable biomass content were tested for their chitin and chitosan content using submerged and surface culture. It is important to mention that surface culture method gave higher records of biomass, chitin and chitosan production compared to submerged culture. So surface fermentation was used in subsequent experiment |