|Chen, Rachel ruizhen|
Submitted to: Biotechnology and Bioengineering
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/2/2006
Publication Date: 12/20/2006
Citation: Shin, H., Mcclendon, S., Le, T., Taylor, F., Chen, R. 2006. A complete enzymatic recovery of ferulic acid from corn residues with extracellular enzymes from neosartorya spinosa nrrl 185. Biotechnology and Bioengineering.V.95, No. 6.p.1108-1114. Interpretive Summary: Fermentation ethanol currently supplies more than 2% of all transportation fuel in the U.S. Among four major sources of supply for U.S. energy needs: petroleum, natural gas, coal, and all others, petroleum supplies the most energy and its use produces the most greenhouse gas emissions. More than half of petroleum supplies are imported, and more than half of petroleum consumption is used for transportation fuel. So that fermentation ethanol can compete more successfully with petroleum-derived transportation fuel, it is necessary to lower the cost of production. Most ethanol in the U.S. is produced from corn. The cost of corn is the major part of the cost of ethanol production. One way to lower the cost of ethanol is to convert underutilized components of the feedstock to valuable co-products, such as ferulic acid. Corn fiber, the non-fermentable part of the corn kernel, is rich in ferulic acid compared to other biomass sources. This paper describes improved enzymatic methods to release 100% of the ferulic acid contained in corn fiber. Successful commercialization of this method could provide a low-cost source for a valuable specialty chemical, while lowering the net cost of ethanol production from corn. This, in turn, will benefit corn producers, the fuel ethanol industry, transportation fuel consumers, the environment and the general public.
Technical Abstract: An economic ferulic acid recovery from biomass via biological methods is of interest for a number of reasons. Ferulic acid is a precursor to vanillin synthesis. It is also a known antioxidant with potential food and medical applications. Despite its universal presence in all plant cell wall material, the complex structure of the plant cell wall makes ferulic acid recovery from biomass a challenging bioprocess. Previously, without pretreatment, very low (3-13%) recovery of ferulic acid from corn residues was achieved. We report here the discovery of a filamentous fungus Neosartorya spinosa NRRL185 capable of producing a full complement of enzymes to release ferulic acid and the development of an enzymatic process for a complete recovery of ferulic acid from corn bran and corn fibers. A partial characterization of the extracellular proteome of the microbe revealed the presence of at least seven cellulases and hemicellulases activities, including multiple iso-forms of xylanase and ferulic acid esterase. The recovered ferulic acid was bio-converted to vanillin, demonstrating its potential application in natural vanillin synthesis. The enzymatic ferulic acid recovery accompanied a significant release of reducing sugars (76-100%), suggesting much broader applications of the enzymes and enzyme mixtures from this organism.