PROCESS ANALYSIS AND ECONOMIC-EVALUATION FOR POLY(3-HYDROXYBUTYRATE) PRODUCTION BY FERMENTATION

Several processes for the production and recovery of poly(3-hydroxybut yrate) (PHB) by Alcaligenes eutrophus, Alcaligenes latus, Methylobacte rium organophilum, and recombinant Escherichia coli were designed base d on the previously reported data and analyzed by computer-aided biopr ocess design. PHB productivity, content, and yield significantly affec ted the final price of PHB. For the annual production of 2,850 tonnes of purified PHB, the process employing A. eutrophus with the recovery method of surfactant-hypochlorite digestion resulted in lowest price o f PHB, $ 5.58/kg. As the production scale increased to one million ton nes per year, the price of PHB dropped to $ 4.75/kg. The cost of carbo n substrate significantly affected the overall economics in large prod uction scale. Therefore, the production cost can be considerably lower ed when agricultural wastes, such as whey and molasses, are used.