Gene and Gene Clusters that Enable Degradation of Recalcitrant Biological Materials
ID: ID1425

Dr. Adam’s group at The University of Georgia has discovered the identity of a group of genes that enable a microorganism to convert untreated woody plant biomass, such as poplar wood chips, to soluble materials that can be used by the same organism or by another to produce biofuels, such as hydrogen and ethanol. The discovery was made from an analysis of the genomes of two very closely related microorganisms Anaerocellum thermophilum and Caldicellulosiruptor saccharolyticus, only one of which, Anaerocellum thermophilum, is able to grow on unprocessed woody plant biomass. The genes that confer this property to Anaerocellum thermophilum are termed PBU for plant biomass utilization. Many of the PBU genes are present in Anaerocellum thermophilum as gene clusters.

Plants with Altered Pectin and Lignin Biosynthesis and with Improved Growth and Recalcitrance
ID: 1542 and 1552

Dr. Mohnen's group at the University of Georgia has identified a clade of genes that are associated with the control of the biosynthesis of both pectin and lignin (and possibly xylan). Mutations of these genes in certain plants (including switchgrass and Populus) lead to considerable reduction of recalcitrance (v. wild type), as shown by means of bacterial degradation of modified biomass. Furthermore, Populus plants bearing some of these mutations have exhibited a considerable increase in height and stem diameter (v.wild type). Plants bearing these mutations may prove suitable for economically viable extraction and use of carbohydrates from plant cell wall, as recalcitrance is greatly reduced and rate of overall growth of modified plants increase.