Chitosan is a natural polysaccharide which is obtained by deacetylation of chitin. Chitin is the main constructive component of exoskeleton of crustacean and one of the most important compounds in fungal cell wall; it converts into chitosan with Chitin Deacetylase in Zygomycetes's cell wall. Chitosan can be separated from other components in two steps: alkali and acid extraction. Biological production of chitosan has some unique advantages such as: production of process raw material with ease and controllability of its quality and high purity of final product. It seems that this process will be in competition with industrial chitosan production process in near future. The aim of this study was biological production of chitosan by means of four different strains: Rhizopus oryzae , Mucor indicuss , Rhizonucor pucillus101 and Rhizomucor pucillus102 and Sacharomyces cerevisiae as a reference microorganism. During the experiments, the effect of cultivation time on chitosan yield was studied and it was specified that in the optimum condition, from one kilogram of dry biomass Rhizopus about 48.4, Mucor indicus 21.7, Rhizomucor pucillus101 8.8, Rhizomucor pucillus102 15.8 and Sacharomyces cerevisiae 6.2 gr chitosan was obtained. We concluded Rhizopus and Mucor were the most powerful microbes for production of ethanol and results showed that in a batch fermentation system the maximum yield of ethanol and chitosan occur simultaneously.