2012 Annual Report
Objective 2: Develop new enzyme-based technologies that enable the production of commercially-viable* coproducts such as specialty chemicals, polymer precursors, and nutritional additives/supplements from raw or pretreated lignocellulosic biomass.
Objective 3: Develop pretreatment technologies that enable commercially-viable* biorefineries capable of utilizing diverse feedstocks such as rice straw, wheat straw, commingled wastes (including MSW), sorghum, switchgrass, algae, and food processing by-products.
Objective 4: Develop new separation technologies that enable commercially-viable* and energy-efficient processes for the recovery of biofuels, biorefinery co-products, and/or bioproducts from dilute fermentation broths.
Greener routes toward production of styrene, terephthalic acid, vanillin and ferulic acid derivatives will be developed by a combination of biochemical and chemical synthetic pathways. Enzymes will be applied to created these bioproduct feedstocks.
Engineering process models, economic analysis, and process parameters for developing integrated biorefineries using biomass from MSW and other under-utilized biomass sources as feedstock will be developed to create a source of cellulose that is consistent, easily converted to bioenergy and available during all seasons.
Develop novel separation methods to reduce energy use and costs for recovering and purifying biofuels/bioproducts from low concentration fermentation broths, especially those resulting from lignocellulosic feedstocks where product concentrations are typically below (sometimes far below) 6 wt%.
Bi-functional enzyme that hydrolyzes both mannans and mixed glucans. Several polysaccharides present in the plant cell wall are often difficult to degrade into fermentable sugars for biofuels production, especially those containing mannan. ARS researchers in Albany, California, developed a bi-functional enzyme that enables two hydrolytic reactions to proceed more efficiently than the corresponding individual reactions that releases mannan-derived sugars (mannose) from complex cell wall components. In related work this team employed site-directed mutagenesis and directed evolution to increase the thermal stability of a highly-active beta-xylosidase by eight degrees Celsius, a significant increase in temperature stability with no loss of activity. This beta-xylosidase, which exhibits one third lower end-product inhibition, has about three fourths the activity of the highest beta-xylosidase reported in the literature but has a much broader pH and temperature range, making it potentially interesting in commercial applications.
Biorefinery strategies to create polymers and polymer building blocks (i.e. green monomers). In order to optimize biorefinery strategies for the Western States, special effort must be made to ensure that multiple product outputs are developed and commercialized, ensuring that no fraction of the biomass is wasted. In two related projects, ARS researchers in Albany, California, have worked with researchers partners to (1) convert waste methane (biogas) to a biodegradable polymer, poly(hydroxy alkanoate), PHA. (2) convert algae- and kelp-derived sugars using specific enzymes to value added chemicals. The monomers produced will be a range of intersting aldaric acids that have been used in nylon production and in anti-freeze formulations. An ARS partnership with a research partner will continue to test the commercial viability of producing aldaric acids as substrates for polymer production at larger scales.
Bilbao-Sainz, C., Bras, J., Williams, T.G., Senchal, T., Orts, W.J. 2011. HPMC reinforced with different cellulose nanoparticles. Carbohydrate Polymers. 86(4): 1549-1557.
Glenn, G.M., Imam, S.H., Orts, W.J., Holtman, K.M. 2012. Starch as a feedstock for bioproducts and packaging. Book Chapter. p. 255-269.
Teixeira, E., Curvelo, A., Correa, A.C., Marconcini, J.M., Glenn, G.M., Mattoso, L.H. 2012. Properties of thermoplastic starch from cassave bagasse and cassava starch and their blends with poly (lactic acid). Industrial Crops and Products. 37: 61-68.
Aouada, F.A., De Moura, M.R., Orts, W.J., Mattoso, L.H. 2011. Preparation and characterization of a novel micro- and nanocomposite hydrogels containing cellulosic fibrils. Journal of Agricultural and Food Chemistry. 59:9433-9442.
Chiou, B., Robertson, G.H., Rooff, L.E., Cao, T., Jafri, H.H., Gregorski, K.S., Imam, S.H., Glenn, G.M. 2010. Water absorbance and thermal properties of sulfated wheat gluten films. Journal of Applied Polymer Science. 116: 2638-2644.
Yu, J., Kohel, R.J., Fang, D.D., Cho, J., Van Deynze, A., Ulloa, M., Hoffman, S.M., Pepper, A.E., Stelly, D.M., Jenkins, J.N., Saha, S., Kumpatla, S.P., Shah, M.R., Hugie, W.V., Percy, R.G. 2012. A high-density simple sequence repeat and single nucleotide polymorphism genetic map of the tetraploid cotton genome. Genes, Genomes, Genetics. 2:43-58.
Robertson, G.H., Cao, T., Orts, W.J. 2008. Effect on dough functioned properties of partial fractionation, redistribution and in-site deposition of wheat flour gluten proteins exposed to ethanol and aqueous ethanol. Cereal Chemistry. 85(5): 599-606.
Robertson, G.H., Cao, T., Orts, W.J. 2007. Wheat proteins extracted from flour and butter with aqueous ethanol at subambient temperatures. Cereal Chemistry. 84(5): 497-501.
Barghin, A., Ivanova, V.I., Imam, S.H., Chielliniam, E. 2010. Poly-(epsilon-caprolactone)(PCL) and poly(hydroxy-butyrate)(PHB) blends containing seaweed fibers: morphology and thermal-mechanical properties. Journal of Polymer Science. 48: 5282-5288.
Imam, S.H., Gordon, S.H., Mohamed, A., Harry O Kuru, R.E., Chiou, B., Glenn, G.M., Orts, W.J. 2006. Enzyme catalysis of insoluble cornstarch granules: impact on surface morphology, property and biogradability. Polymer Degradation and Stability. 91(12): 2894-2900.
Orts, W.J., Shey, J., Imam, S.H., Glenn, G.M., Guttman, M.E. 2005. Application of cellulose microfibrils in polymer nanocomposites. Polymers and the Environment. 13: 4.
Ogawa, Y., Orts, W.J., Glennm, G.M., Wood, D.F. 2003. A simple method for studying whole sections of rice grain. Biotechnic & Histochemistry. 78(5):237-242.
Jordan, D.B., Bowman, M.J., Braker, J.D., Dien, B.S., Hector, R.E., Lee, C.C., Mertens, J.A., Wagschal, K.C. 2012. Plant cell walls to ethanol. Biochemical Journal. 442:247-252.
Ogawa, Y., Glenn, G.M., Orts, W.J., Wood, D.F. 2003. Historical structures of cooked rice grain. Journal of Agricultural and Food Chemistry. 51:7019-7023.