发布时间 :2012-03-28  阅读次数 :2048

报告题目:Bioprocessing Aspects of Fuels and Chemicals from Biomass: raw materials, conversion technologies ,     productivity,  and titer
报告人:Prof. Ho Nam Chang

Ho Nam Chang, Professor of Biochemical Engineering, Department of Chemical & Biomolecular Engineering,            KAIST; Fellow of Korea Academy of Science and Technology ; Member of National Academy of Engineering, Korea ;Vice President, National Academy of Engineering, Korea

        Lignocellulosic and aquatic biomasses are considered as an alternative to current grain-based fuel ethanol and biodiesel in a near future. Because of huge quantities and low cost nature we need to look into the various aspects of bioprocessing technology whether they may fit into our new applications. The author’s group has devoted many years of attention and concentrated efforts to replace raw materials, conversion technologies, bioreactor productivity and product titer through simple economic evaluation of new technologies.
The cost of raw materials accounts for 70~80% of the manufacturing cost of grain-based biofuels.  Lignocellulosic biomass has advantage over fuel grains in terms of abundant quantities and cost but it has lower conversion efficiencies, likewise lower titer and productivities. Biodegradable waste raw materials of food wastes, cattle manure, sludge and even seasonal fallen leaves have a lower or even negative raw material cost. MSC-HCDC (multistage continuous high cell density culture) renders 10 times higher productivities of the current commercial fed-batch system with equivalent titer.  Membrane technology of reverse osmosis and forward osmosis has a higher energy efficiency and material cost than heat-based distillation and solvent-based extraction since membrane technology rarely involves phase (latent heat) and temperature (sensible) changes.
     MSC-HCDC technology still needs to solve many things prior to its commercial application: (1) how to achieve reliable high cell density culture for long-term operation (2) how to maintain high cell density culture in several reactors; (3) use of industrial substrates containing many particles. Anaerobic mixed culture technologies are employed instead of current sugar-based and syngas (chemical) technologies, which makes it possible for any methane generating raw material to be considered as potential future materials for biofuels.  An application of forward osmosis makes possible 4 times enrichment of 3.5% to 14.0% volatile fatty acids (VFAs) and succinic acids 2-fold. We are now challenging even higher percentage enrichment of fermentation broth using a new concept membrane technology. Many anticipated industrially difficult problems arising from making mixed alcohols and microbial biodiesel such as particulate feed solutions are first identified, solved conceptually and to be experimentally tested on laboratory scale followed by bench and pilot scales in a near future.