Clean Technology

Most Recent Inventions

Novel Catalysts for Improved Remediation of Sulfur-Containing Pollutants

A professor of chemistry at the University of Wisconsin-La Crosse has developed a versatile suite of iron-based catalysts with the potential to promote rapid, efficient oxidation of deleterious sulfur-containing compounds present in crude oil, natural gas, and/or aqueous waste streams. With these novel catalysts, there is no need for corrosive base, elevated temperatures, expensive or dangerous oxidants, or high pressures.

Production of Medium-Chain Fatty Acids from Biorefinery Residue

UW–Madison researchers led by Profs. Daniel Noguera and Timothy Donohue have developed a method for converting unreacted chemical components in stillage to valuable medium-chain fatty acids, such as hexanoic and octanoic acids, using a mixture of microbes (e.g., anaerobic microbiome).

Operationally, a portion of the stillage stream is separated and fed to a bioreactor containing the mixture of microbes, which transforms a fraction of the stillage to MCFAs. The other fraction of the stillage can be sent on to the anaerobic digester to generate electricity (similar to existing biorefineries).

One-Step Process to Generate Lignin-Derived Aromatics from Raw Biomass

UW–Madison researchers have developed a one-step, “lignin-first” method for generating lignin-derived aromatics from raw biomass. The new approach uses transition metal-based heterogeneous catalysts under neutral pH conditions with O2 as the oxidant. Compared to traditional biomass deconstruction approaches, which first isolate lignin from the feedstock before further processing for recovery of sugars, the lignin-first method avoids the cumbersome and destructive lignin extraction process.

While not optimized for sugar recovery, the carbohydrate residues are not degraded and remain intact for further processing.

Enzymatic Depolymerization of Lignin

UW–Madison researchers provide the first demonstration of an in vitro enzymatic system that can recycle NAD+ and GSH while releasing aromatic monomers from natural and engineered lignin oligomers, as well as model compounds composed of similar chemical building blocks. Nearly 10 percent of beta-ether units were cleaved when the system was tested on actual lignin samples.

The relevant enzymes include dehydrogenases, β-etherases and glutathione lyases. In an exemplary version, the system uses the known LigD, LigN, LigE and LigF enzymes from Sphingobium sp. strain SYK-6. A newly discovered heterodimeric β-aryl etherase (BaeA) can be used in addition to or instead of LigE.

Low Cost Bio-based PLA and Lignin Composite Thermoplastic Filaments for 3D Printing Applications

University of Wisconsin-Platteville professors in engineering and chemistry have developed a proprietary production process for creating novel thermoplastic biocomposite polymers for 3D printing applications using renewable agriculture and forest waste materials. These polymers are a blend of plant-based PLA combined with lignin extracted from wood by the organosolv method. Pellets and long-strand filaments made from these biocomposites are suitable for additive printing using extrusion-based printers and offer several advantages over preexisting filaments, including reduced material cost, adjustable mechanical properties, potential flame retardation, ultraviolet shielding and biodegradable properties.

Most Recent Patents

Modified Yeast to Boost Biofuel Yields

A UW–Madison researcher has developed an S. cerevisiae strain that is 80 percent more effective at fermenting xylose. He discovered that knocking out several genes (hog1, isu1, gre3, ira1/2) enables dramatically faster xylose fermentation under the anaerobic conditions favored by industry.

Grass Modified for Easier Bioprocessing

The researchers have identified another gene of interest in rice, corn/maize and other grasses, called p-coumarate monolignol transferase (PMT). This is the first gene reportedly involved in the acylation of lignin monomers. In essence, interfering with this gene could make plants more amenable to biorefining.

Industrial Streptomyces with Capability to Grow on Cheap and Abundant Cellulose

Building on their work, the researchers have developed an optimized set of enzymes useful to create Streptomyces with the capability to grow on cellulosic polysaccharide substrates. The method enables industrially relevant strains to grow on cellulose as the sole carbon source.

Using an engineered plasmid expression system derived from the ActE strain, the researchers transformed two commercial species (S. lividans and S. venezuelae) and showed that they were able to grow on filter paper as the sole carbon source. Other suitable host stains include S. coelicolor, S. griseus, S. clavuligerus, S. hygroscopicus, S. viridochromogenes and S. avermitilis.