Fungi play key roles in nature and are valued for their great importance in industry. Consider citric acid, a key additive in several foods and pharmaceuticals produced on a large-scale basis for decades with the help of the filamentous fungus Aspergillus niger. While A. niger is an integral player in the carbon cycle, it possesses an arsenal of enzymes that can be deployed in breaking down plant cell walls to free up sugars that can then be fermented and distilled into biofuel, a process being optimized by U.S. Department of Energy researchers. In work published online ahead of print on May 4, 2011 in Genome Research, a team led by Dr. Scott Baker of the Pacific Northwest National Laboratory compared the genome sequences of two Aspergillus niger strains in order to, among other things, better harness its industrial potential in biofuels applications. As more than a million tons of citric acid are produced annually, the production process involving A. niger is a well understood fungal fermentation process that could inform the development of a biorefinery where organic compounds replace the chemical building blocks normally derived from petroleum. Learning more about the genetic bases of the behaviors and abilities of these two industrially relevant fungal strains, wrote senior author Dr. Baker and his colleagues in the paper, will allow researchers to exploit their genomes towards the more efficient production of organic acids and other compounds, including biofuels. "Aspergillus niger is an industrial workhouse for enzymes and small molecules such as organic acids," said Dr. Baker of the fungus selected for sequencing by the DOE JGI (Department of Energy Joint Genome Institute) in 2005. "Most of the world's citric acid comes from A. niger.
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