Clean Technology

Most Recent Inventions

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.

Organic Polymers with Ultra-Small Pores for Carbon Dioxide Separation, Capture, and Conversion

Researchers at the University of Wisconsin – Platteville have synthesized an array of chemically and thermally stable organic polymers comprised of ultra-small pores capable of separating out and capturing carbon dioxide molecules from a mixture of gases. These include phenazine linked polymers (PLPs), glyoxal‐derived polymers (GDPs), benzoxazole‐linked polymers (BOLPs), and benzothiazole‐linked polymers (BTLPs) with each having nitrogen-rich functionality to attract CO2. The single component adsorption isotherms demonstrated that the polymers have exceptionally high CO2 capture ability over CH4 and N2 with maximum adsorption selectivity of 35 times greater and 140 times greater, respectively, at 25°C. Such polymers have utility in the formation of membrane composites for use in membrane gas separation technology. Additionally, the researchers have been able to combine these polymers with silver metal resulting in the catalytic conversion of carbon dioxide molecules to useful chemical compounds.

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.

Modified Cyanobacteria for Competitive Sugar Production

UW–Madison researchers have developed strains of Synechococcus sp. Strain PCC 7002 with the highest reported glycogen or starch production rate of any cyanobacteria or algae. The strains are genetically modified to overexpress a glucose-1-phosphate adenylyltransferase.

Boron- and Nitride-Containing Catalysts for Oxidative Dehydrogenation of Small Alkanes and Oxidative Coupling of Methane

UW–Madison researchers have developed improved ODH catalysts for converting short chain alkanes to desired olefins (e.g., propane to propene and ethene) with unprecedented selectivity (>90 percent).

The new catalysts contain boron and/or nitride and minimize unwanted byproducts including CO and CO2. They contain no precious metals, reduce the required temperature of the reaction and remain active for extended periods of time with no need for costly regenerative treatment.

In addition to driving ODH reactions, the new catalysts can be used to produce ethane or ethene via oxidative coupling of methane (OCM).

Most Recent Patents

More Efficient Water-Splitting Cells

UW–Madison researchers have developed a method for synthesizing nanoporous BiVO4 electrodes with large surface areas. The material is made up of a porous network of BiVO4 particles smaller than 150 nm and coated with oxygen evolution catalyst. The small size of the particles addresses prior drawbacks by increasing a property called electron–hole separation yield. The material is made by applying a vanadium solution to a type of bismuth crystal. The mixture is heated and converted into a porous network of BiVO4 particles.

Visible-Range Sunlight Drives CO2 Reduction Process for Cheaper Syngas

UW–Madison researchers have developed a new method of reducing CO2 to CO via a reverse water gas shift reaction using visible solar light. The reaction produces a syngas mixture which can be further converted to liquid fuels.

In this process, CO2 (which can be obtained from many industrial processes) is contacted with a plasmonic catalyst in the presence of hydrogen. The catalyst is exposed to visible-range sunlight so that it undergoes an optical phenomenon called surface plasmon resonance, which causes metal electrons to oscillate in a certain way and accelerates the rate of CO2 reduction.

The process results in CO2 being reduced to water and CO that can be collected for downstream products.

Microbes Produce High Yields of Fatty Alcohols from Glucose

UW–Madison researchers have developed a method to produce fatty alcohols such as 1-dodecanol and 1-tetradecanol from glucose using genetically engineered microorganisms. The organism, e.g., a modified E. coli strain, overexpresses several genes (including FadD and a recombinant thioesterase gene, acyl-CoA synthetase gene and acyl-CoA reductase gene). Other gene products are functionally deleted to maximize performance.

The strain is cultured in a bioreactor in the presence of glucose.