Compositions and methods for producing chitin and chitosan are provided. The compositions comprise genetically modified organisms, including fungi, yeast, bacterial and plant organisms that have been engineered to express heterologous genes involved in chitin and chitosan synthesis. Microorganisms and plants that have been modified for production of chitin and/or chitosan within the vacuole of a cell are encompassed. Methods for production of chitin also comprise culturing the genetically engineered organisms in conditions that allow for chitin production. Further methods include converting the chitin to chitosan by a chemical process. Production of chitosan also comprises culturing organisms that are genetically modified to produce chitosan without the need for chemical. | [0006] Chitin and chitosan are related polymers that are produced by several types of fungi and yeasts as part of their cell wall. One approach to improving commercial chitosan production methods would be to engineer existing fermentation strains to produce more chitin/chitosan as a value-added product. For example, Rhizopus oryzae or Aspergillus niger strains utilized for citric acid production contain substantial amounts of chitin/chitosan, and thus are an attractive source for a value-added approach. Alternatively, a fermentative yeast can be engineered to produce chitosan as a component of its cell walls. Regardless of the approach, when chitin/chitosan are to be produced as a value-added product in an existing fermentation system, care must be taken to ensure that the yield of the primary fermentation product is not reduced and that the processing of the primary fermentation product is not altered in the process. An attractive approach would be to develop a cell expression system that is dedicated to production of chitin/chitosan.
