Applications

• Biofuels
• Other value-add products, e.g., aromatics, organic acids

Advantages/Benefits

• One-step low temperature conversion of whole biomass into value-added products
• Control over aliphatic acid profile as a function of reaction coordinates 

Background

Current state-of-the-art technology for the conversion of lignocellulose into value-added products requires a multi-step conversion process, including separation of biopolymers, saccharification of holocelluloses, sugar fermentation, and lignin conversion. A one-step method that can fractionate lignocellulosic biomass efficiently would be highly advantageous.

Technology Overview

This technology developed at the Joint BioEnergy Institute is a one-step method for oxidizing lignocellulosic biomass into aliphatic acids. In the method, biomass is passed over a catalytic amount of POM-ILs in subcritical water under mild conditions. Polyoxometalates (POMs), which are recognized as a commercially viable option to oxidize lignin into aliphatic acids, are coupled with asymmetric cations to form low melting salts known as ionic liquids (ILs). Subcritical water, being non-toxic, non-flammable, and non-explosive, offers unique solvent characteristics for extraction and hydrolysis. 

Scientists achieved a total yield of 454 mg of acids per gram of lignin with 8.06 wt% oxidant loading and biorefinery lignin as the substrate. The main acids produced were oxalic acid, formic acid, and acetic acid, at 98, 225, and 84 mg/g, respectively. These acids were then successfully used for microbial consumption, with over 90% being utilized.

Furthermore, the concept was expanded to “lignin-first” oxidative catalytic fractionation of lignocellulosic biomass (sorghum, poplar, and pine) to selectively depolymerize lignin into aliphatic acids (achieving 800-1200 mg acids per g of lignin) while leaving behind glucan-rich solids. Researchers have shown that these solids are easily accessible by enzymes for hydrolysis into monomeric sugars. 

Development Stage

Proof of concept

Principal Investigator(s)

• Hemant Choudhary
• Mood Mohan
• Blake A. Simmons
• John M. Gladden
• Seema Singh

Status

Patent Pending 

Opportunities

Available for licensing or collaborative research