Development of a Novel, Cost-Effective Bioprocess for Production of Fuel Ethanol from Herbaceous Lignocellulosic Wastes
Durmishidze Institute of Biochemistry and Biotechnology of Georgian Agrarian University
Proposed project is focused on a Consolidated Bioprocessing (CBP) strategy, and aims to substantially contribute to the development of an economically sound and environmentally safe biotechnology process for fuel ethanol production from lignocellulosic materials. The overall goal of the project is the development of a novel bioprocess for cost effective production of ethanol from herbaceous lignocellulosic wastes, such as corn stalks and wheat straw. The main objective of the project is the development of a syntrophic microbial consortium for ethanol production in a single-stage process. Specific approaches proposed for project realization involve (i) collection and characterization of thermophilic, cellulolytic, and saccharolytic anaerobic bacteria in the genus Clostridia endemic in more than 12 soil/climate zones of Georgia; (ii) screening of hypercellulolytic and C5 and C6 sugars fermenting strains with improved ethanol productivity and decreased acids production; (iii) identification of industrially relevant, robust microorganisms with extended tolerance to high substrate, ethanol, and fermentation inhibitors; (iv) development of a stable, syntrophic microbial consortium, which will directly convert herbaceous lignocellulosic wastes, such as corn stalks and wheat straw to fuel ethanol; (v) testing the efficiency of a CO2-based freeze explosion pretreatment method for increasing digestibility of herbaceous biomass; (vi) optimization of ethanol production in batch and continuous fermentations with recycled cells; and (vii) testing a stable, syntrophic microbial consortium for herbaceous biomass direct conversion to ethanol at a 3-30-liter scale. Considering that the Clostridium-based fermentation by-products, hydrogen and volatile fatty acids, are highly valuable commercial products that may be used for energy production on-site, an optimized scheme for their use will be developed. Finally, cost benefit and mass and energy balance analyses for ethanol fermentation using a syntrophic microbial consortium and use of fermentation by-products will be conducted. Cooperation of highly qualified Georgian researchers and engineers with advanced foreign scientists will guarantee successful realization of the project. Considering the rapidly increasing worldwide demand for environmentally sound and low-cost automotive fuel, specific project results, such as unique collections of endemic anaerobic, thermophylic cellulose-degrading and ethanol-producing clostridia; novel strains of hipercellulolytic and ethanol-tolerant bacteria; C5 and C6 sugars fermenting strains with improved ethanol productivity and decreased acid production; strains capable to simultaneously ferment C5 and C6 sugars; syntrophic microbial consortia for direct conversion of herbaceous biomass to ethanol have extremely high potential for commercialization. For this purpose, substantial effort will be made to establish business contacts with research teams and companies involved in cellulosics-based fuel ethanol R&D and production.