Image courtesy of Joint BioEnergy Institute
To optimize plant feedstocks for bioenergy, researchers engineered a viable plant (#89) whose cell walls contain less lignin—a robust, degradation-resistant structural polymer—and more polysaccharides, or sugars that can be converted into biofuels (lower panel).
Polysaccharides (complex chains of sugar) in plant cell walls are great carbon energy sources for biofuel production. However, these sugars are embedded in lignin, a structural biopolymer that gives plants their required rigidity but also impedes enzymatic release of simple sugars. Previous attempts to reduce lignin content in plant vascular tissue were imprecise and impaired plant growth due to loss of vessel integrity. Researchers have developed a new approach to decrease lignin content, increase the yield of fuel sugars, and still ensure plant tissue integrity.
Such an approach demonstrates promise for developing bioenergy feedstocks optimized for more efficient deconstruction and sugar release.
In this work, researchers engineered lignin and polysaccharide biosynthesis pathways in a cell-type specific manner. In the naturally lignin-rich fiber cells, lignin was significantly reduced, and in vessel cells, polysaccharide content was much greater. The resulting plants were viable and grew normally. When biomass from these engineered plants was subjected to enzymatic digestion, more sugars were released than in wild type plants because of both the increased polysaccharide deposition and reduced lignin content in the cell walls.
Joint BioEnergy Institute, Physical Biosciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Road
This work, conducted by the U.S. Department of Energy (DOE) Joint BioEnergy Institute, is supported by the Office of Biological and Environmental Research within the DOE Office of Science through contract DE-AC02-05CH11231 between Lawrence Berkeley National Laboratory and DOE.
Yang, F., et al. “Engineering secondary cell wall deposition in plants.” Plant Biotech. J. 11 (3), 325–335 (2013). [DOI: 10.1111/pbi.12016]
BER, BRCs, BSSD
University, DOE Laboratory