Sugar and ethanol conversion of recovered whole and degermed corn kernel fibers pretreated with sodium carbonate

Authors: Garcia-Negron, Valerie; Johnston, David

Submitted to: Fermentation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/14/2026
Publication Date: 1/21/2026
Citation: Garcia-Negron, V., Johnston, D. 2026. Sugar and ethanol conversion of recovered whole and degermed corn kernel fibers pretreated with sodium carbonate. Fermentation. https://doi.org/10.3390/fermentation12010061.
DOI: https://doi.org/10.3390/fermentation12010061

Interpretive Summary: Corn, a starch-rich biomass, is the principal source for producing ethanol fuel via the conversion of fermentable sugars. Corn fiber is a by-product of corn-ethanol processes that can be recycled into the process with whole corn for production of additional ethanol with no significant process changes; however, corn fiber needs to first be treated to help release the sugars it contains. In this work whole and degermed corn kernel fiber was pretreated with sodium carbonate and subjected to hydrolysis and fermentation for 72 hours. Results shows a total sugar conversion of 70% specifically for the pretreated corn kernel fibers. Mixtures of corn fiber and corn containing 10 and 20% solids were fermented producing sugars and maintaining consistent ethanol yield. Results indicate that the conversion of recovered fibers are similar for both degermed and whole corn kernels. Moreover, incorporating the recovered pretreated fiber can decrease processing costs in existing corn ethanol facilities.

Technical Abstract: Processing corn in biorefineries generates residual biomass and co-products having additional potential value for conversion to ethanol. Recovered corn fiber can be pretreated and used as a supplemental biomass in subsequent corn ethanol production. Whole and degermed corn kernel fiber recovered from fermentation during corn-ethanol production were pretreated with sodium carbonate and reutilized in subsequent fermentation for additional ethanol production. Sugar yields from enzymatic hydrolysis show that sodium carbonate helps promote saccharification reaching over 70% total sugar conversion from the recovered corn kernel fiber. Fermentation studies evaluated the use of recovered corn fiber as supplemental biomass for corn during ethanol production. Mixtures containing 10% and 20% corn produced additional xylose and arabinose when supplemented with recovered corn fiber, while ethanol yields remain consistent. Post fermentation corn kernel fiber can be pretreated to become suitable co-fermentation candidates as it helps promote additional ethanol and sugar conversions. Conversion rates and yields are similar between pretreated whole and degermed corn fiber demonstrating the additional value from the recovered biomass.