ARS | Publication request: CORN FIBER HYDROLYSIS BY THERMOBIFIDA FUSCA EXTRACELLULAR ENZYMES

Submitted to: Applied Microbiology And Biotechnology
Publication Acceptance Date: November 22, 2002
Publication Date: January 25, 2003
Citation: Irwin, D., Leathers, T.D., Greene, R.V., Wilson, D.B. Corn Fiber Hydrolysis By Thermobifida Fusca Extracellular Enzymes. Applied Microbiology And Biotechnology. 2003. V. 61. P. 352-258.

Interpretive Summary: Practical new methods are needed to produce fermentable sugars from low-value agricultural residues such as corn fiber. Enzymes from thermophilic bacteria are attractive for the conversion of corn fiber to sugars because they function at elevated temperatures. This work will be valuable to researchers developing methods to convert agricultural biomass to value-added biofuels and bioproducts.

Technical Abstract: Thermobifida fusca was grown on cellulose (Solka-Flok), xylan, or corn fiber, and the supernatant extracellular enzymes were concentrated. SDS gels showed markedly different protein patterns for the three different carbon sources. Activity assays on a variety of synthetic and natural substrates showed major differences in the concentrated extracellular enzyme activities. These crude enzyme preparations were used to hydrolyze corn fiber, a low value biomass byproduct of the wet milling of corn. Approximately 180 mg of reducing sugar equivalents were produced per g of untreated corn fiber. When corn fiber was pretreated with alkaline hydrogen peroxide, up to 400 mg reducing sugars were released. Saccharification was enhanced by the addition of beta-glucosidase or by the addition of a crude xylanase preparation from the yeastlike fungus Aureobasidium.