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).

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.

High Yield Method to Produce HMF from Fructose

UW–Madison researchers have discovered that a solvent system comprising water and a polar aprotic solvent (e.g., acetone) is ideally suited for converting C6 carbohydrates into HMF at reasonably low temperatures (such as 120°C), low acid concentration and at very high yields and efficiencies.

The C6 carbohydrate used in the method can be derived from any source including biomass (processed or unprocessed), cellulose and lignocellulosic sources, etc. The nature of the C6 carbohydrate is not critical to the method, although fructose is preferred.

Recyclable Catalyst for Lower Cost Production of Fermentable Sugars and High Value Chemicals from Biomass

An assistant professor in chemical engineering at the University of Wisconsin-Stevens Point and former senior research scientist at the Montana State University Bio-Energy Center have developed a technology that reduces the processing cost and time to fractionate lignocellulose into fermentable sugars. The technology is centered on the use of a catalyst linked to a magnetic bead, which replaces the need for acids and enzymes in the pretreatment step of the production process. Because of its magnetic properties, the catalyst can easily be recovered from the reaction mixture and reused multiple times. It is also capable of functioning under cellulose loads as high as 50%, whereas loads for competing solid acid catalysts have been typically limited to less than 15%. The end result is a process that makes better use of carbon-neutral biomass by lowering production costs and increasing yield of desirable monomer sugars and high value chemical compounds such as vanillin, phenol, acetophenone.

Most Recent Patents

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.

Rechargeable Desalination Battery

UW–Madison researchers have designed a rechargeable desalination cell that can operate on seawater and is capable of performing a desalination/salination cycle with a net potential input as low as 0.2 volts. The cell comprises a sodium-storage electrode coupled to a chloride-storage electrode made of nanocrystalline bismuth foam.

The bismuth-based electrodes are able to store chloride ions in their bulk by oxidizing Bi to BiOCl in the presence of an oxygen source, such as water. Advantageously, BiOCl is insoluble in water over a wide pH range and inert against water oxidation. It also is stable over a wide range of anodic potentials. As a result, the new electrodes can be used for chloride removal in a variety of aqueous sources.

The BiOCl electrode can be converted back to a bismuth electrode by a reduction reaction, where the chloride ions are released into the electrolyte. This reverse reaction allows for the repeated use of the electrode for chloride storage/release via multiple chlorination/dechlorination cycles.