A Co-fermentation Strategy to Efficiently Co-ferment Mixed Sugars
Application(Product)Productionof biofuels and other commodity chemicals such as succinate and pyruvate fromany hydro-lyzed cellulosic biomass, through the simultaneous fermentation ofpentoses and hexoses.ProblemsAddressed (benefits/advantages)The efficient use of agricultural biomass forthe production of any biochemical is problematic. Technical challenges to beovercome in order for bio-based industrial products to be cost-competitiveinclude find-ing new technology and reducing the cost of technology forconverting biomass into desired bio-based industrial products. Researchresulting in cost-effective technology to overcome the recalcitrance ofcel-lulosic biomass would allow bio-refineries to produce fuels and bulkchemicals on a very large scale. The untapped sources of biomass are largelylignocellulosic in nature. One promising use of lignocellulose for liquid fuelis in the microbial production of ethanol. Unfortunately, when broken down intoconstituents, a very complex mixture remains. This mixture contains sugars(e.g., pentoses, hexoses and oligo/polysaccharides) which individually but notcollectively are suitable for fermentation, and the mixture also containsinhibitors. The pentose:hexose (C5:C6) ratio from different substrates canrange from ca. 70:30 to 15:85. Because the unit value of chemical productsderived from biomass (e.g., ethanol) is gen-erally low while the potentialmarket is large, the economic viability of such processes depends on the yieldand productivity. Yield is the quantity of product formed per mass of materialinput, while produc-tivity is the rate at which the product is generated.Achieving high yield demands that all biomass com-ponents be converted, whilehigh productivity requires that the complex conversions be accomplishedquickly. Currently, technologies that allow for the efficient and simultaneousconversion of both “C5” and “C6”, at any C5:C6 ratio is inexistent.
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