Metabolic Engineering of Caldicellulosiruptor bescii for the Production of Biofuels and Bioproducts
- 详细技术说明
- Application (Product) Engineeredorganisms for the high temperature conversion of cellulosic biomass intobiofuels and bioproducts. Problems Addressed (benefits/advantages)Biomass is a renewable resource that can be processed into myriadof chemicals and has shown promise to replace petroleum-based fuels and othermaterials. Sugars contained withinnaturally occurring biomass can be transformed into ethanol and otherproducts. However, the cost ofbiomass-based fuels historically has not been competitive relative to oil or otherenergy resources. The biochemicalconversion step, where plant sugar is converted to fuel, has been veryexpensive. The presence of lignin,lignocellulose and other compounds hinder direct processing of biomass bybacteria, yeasts and enzymes. Thishindrance, also known as “biomass recalcitrance”, often requires expensivepretreatment of biomass prior to its transformation into useful products suchas biofuels.Caldicellulosiruptorbescii, athermophilic bacterium, has a high affinity for decomposing lignocellulosicbiomass, which includes agricultural residues such as rice straw, switchgrass,as well as hard- and softwoods. Lignocellulosic biomass consists of cellulose, hemicellulose, pectin andlignin. Caldicellulosiruptor are amongthe most thermophilic and cellulolytic bacteria, which enables them to degradeuntreated biomass. This characteristicmakes this organism especially appealing to biomass processing. However, its inability to produce compoundsof economic interest require that the organism be modified in order to enableits use in industrial processes for the production of biofuels and othercommodity chemicals.
- *Abstract
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TechnologySummary
Dr.Westpheling group at UGA developed a method, involving the use of C. bescii, to more efficiently decomposebiomass. The Caldicellulosiruptor bacterium has unique properties forprocessing a type of lignocellulosic biomass. By genetically manipulating C. bescii through the introduction of keygenes (thus altering the organism’s metabolism) that allow the production ofdesired chemicals from biomass, the researchers have shown that ethanol can bemore easily created.
Specifically,the researchers have developed methods for genetic manipulation of members ofthis Caldicellulosiruptor genus, enabling them to produce ethanol and hydrogenfrom biomass. For example, genes from C. thermocellum, which is the best-knownthermophilic ethanol producer, were cloned and introduced into C. bescii. Other genes, from Clostridium thermocellum, can similarly be introduced allowing thebacterium to convert acetate to acetaldehyde. Furthermore, the same approach can be used to produce hydrogen. Hence, the ability to engineer C. bescii offers the possibility ofdirect conversion of biomass to biofuels and bioproducts commodity biochemicals,such as alcohols, furans, lactones and long chain acids and keto-acids, andeven H2 from biomass.
Advantages and Some Potential Applications
Modified Caldicellulosiruptorbescii bacterium has special decomposition properties that enable the moreefficient conversion of lignocellulosic biomass into fuel.
This novelinvention of introducing key genetic traits into C. bescii will significantlyreduce the high cost of biomass conversion by eliminating expensive enzymes,yeasts, and bacteria.
Increasedbiomass-to-biofuel efficiency using this modified C. bescii will have amajor impact on the energy industry by decreasing production cost, thus makingit more economical to produce biomass-based ethanol versus petroleum-basedfuels.
Inventor
JanetWestpheling
Technology Development and IP Status
Lab scale.
US IssuedPatent 9,309,542
- 国家/地区
- 美国
