Time filter

Source Type

Bells Corners, Canada

Wang J.,University of Guelph | Quirk A.,University of Guelph | Lipkowski J.,University of Guelph | Dutcher J.R.,University of Guelph | And 3 more authors.
Langmuir | Year: 2012

The biodegradation of cellulose involves the enzymatic action of cellulases (endoglucanases), cellobiohydrolases (exoglucanases), and β-glucosidases that act synergistically. The rate and efficiency of enzymatic hydrolysis of crystalline cellulose in vitro decline markedly with time, limiting the large-scale, cost-effective production of cellulosic biofuels. Several factors have been suggested to contribute to this phenomenon, but there is considerable disagreement regarding the relative importance of each. These earlier investigations were hampered by the inability to observe the disruption of crystalline cellulose and its subsequent hydrolysis directly. Here, we show the application of high-resolution atomic force microscopy to observe the swelling of a single crystalline cellulose fiber and its-hydrolysis in real time directly as catalyzed by a single cellulase, the industrially important cellulase 7B from Trichoderma reesei. Volume changes, the root-mean-square roughness, and rates of hydrolysis of the surfaces of single fibers were determined directly from the images acquired over time. Hydrolysis dominated the early stage of the experiment, and swelling dominated the later stage. The high-resolution images revealed that the combined action of initial hydrolysis followed by swelling exposed individual microfibrils and bundles of microfibrils, resulting in the loosening of the fiber structure and the exposure of microfibrils at the fiber surface. Both the hydrolysis and swelling were catalyzed by the native cellulase; under the same conditions, its isolated carbohydrate-binding module did not cause changes to crystalline cellulose. We anticipate that the application of our AFM-based analysis on other cellulolytic enzymes, alone and in combination, will provide significant insight into the process of cellulose biodegradation and greatly facilitate its application for the efficient and economical production of cellulosic ethanol. © 2012 American Chemical Society. Source

Iogen Corporation | Date: 2013-03-15

The present invention provides a method for reducing life cycle GHG emissions associated with production of a liquid fuel or fuel intermediate. The method comprises: fermenting sugar to produce biogenic carbon dioxide and the liquid fuel, fuel intermediate or a fuel source; collecting an amount of biogenic carbon dioxide generated from the fermentation; and supplying the biogenic carbon dioxide for use in one or more enhanced oil or gas recovery sites for displacement of geologic carbon dioxide and deriving a greenhouse gas emissions benefit. Further provided is a method comprising receiving an amount of carbon dioxide from an apparatus for delivering carbon dioxide to one or more enhanced oil or gas recovery sites so as to displace the use of geologic carbon dioxide at the site. The carbon dioxide received has the GHG emission attributes of the biogenic carbon dioxide introduced to the apparatus.

Iogen Corporation | Date: 2013-03-15

The present invention provides a process comprising collecting or sourcing biogenic carbon dioxide from a fermentation that produces a fuel, fuel intermediate or fuel source from organic material. The fermentation may be an anaerobic digestion to produce biogas or a fermentation of sugar to produce a liquid fuel. The biogenic carbon dioxide arising from the fermentation is subsequently supplied to one or more sites that use carbon dioxide in an industrial application for displacement of geologic carbon dioxide which derives a greenhouse gas emissions benefit. Such an industrial application may include using the biogenic carbon dioxide as an additive, a processing agent, a treatment agent, a cooling agent, or a carbon source to make fuels, chemicals or polymers.

The present invention provides a process for producing one or more products for use as a transportation or heating fuel. In various embodiments the process comprises treating a cellulosic feedstock in one or more processing steps that release extractives from the feedstock. A solids-liquid separation is subsequently conducted on the process stream comprising the extractives and solids. An aqueous stream comprising one or more of the extractives may be fed to an anaerobic digester to produce crude biogas from which one or more impurities may optionally be removed. In various embodiments the process further comprises providing a solids stream to a thermal process. A product produced or derived from the thermal process may displace a product made from fossil fuel. One or more products obtained or derived from at least one of the foregoing process steps are provided for use as a transportation or heating fuel. In various embodiments the process enables advantaged fuel credit generation.

A method for killing or substantially eradicating a pathogen in the upper respiratory tract of a mammal is disclosed. The method comprises generating molecular iodine (I

Discover hidden collaborations