ARS | Publication request: Removal of Inhibitors from Biomass Sugars Using a Biological Process

Submitted to: Biotechnology for Fuels and Chemicals Symposium Proceedings
Publication Type: Abstract
Publication Acceptance Date: May 2, 2007
Publication Date: N/A

Technical Abstract: A major constraint to fermentation of sugars in biomass hydrolysates is the presence of side-products of hydrolysis that are toxic to microorganisms. These chemicals include products of sugar degradation (furfural, 5-hydroxymethylfurfural (HMF), and levulinic acid), organic acids released from hemicellulose side-groups, and aldehydes, phenolics, and organic acids released from lignin. These products are especially problematic because their inhibitory effects can be synergistic in blocking fermentation. We are developing a bioremediation strategy to detoxify biomass sugars prior to fermentation. A fungal strain (Coniochaeta ligniaria NRRL30616), isolated by us from an industrial soil sample, metabolizes furfural and HMF as well as a number of aromatic and aliphatic acids and aldehydes. When evaluated on corn stover dilute-acid hydrolysates, the fungus was found to readily grow and remove a number of inhibitors, including furfural and HMF. Analytical extraction of corn stover hydrolysate, followed by HPLC and LC-MS analysis, has been used to further quantitate a wide-variety of aromatic acid, aliphatic acid, aldehyde, and phenolic compounds, and follow their fate during growth of C. ligniaria in hydrolysate. Biological abatement of the hydrolysates was determined to improve ethanol yield and productivity of glucose and xylose fermentations.