Gene for p-Coumarate Knock Down

Introduction

Lignin, an abundant polymer of vascular plants that provides structural integrity to the plant cell wall, is the second most abundant polymer on earth and critical to the strength and survival of terrestrial plants. Unfortunately, its mechanical strength and resistance to chemical degradation, which is so essential for plant health, are problematic when trying to use plants as feedstocks for certain industrial and feed applications.

Description of Technology

Michigan State University (MSU), in collaboration with the University of Wisconsin and the University of British Columbia, has developed a suite of technologies for the genetic engineering of a new type of modified lignin plants. The modified plants have normal amounts of lignin that is easily extracted under mildly alkaline conditions. Unlike many prior attempts at lignin modification, this altered lignin will function properly in the cell wall, thus maintaining critical functions in the plant and avoiding adverse effects on crop growth and yield.

These particular inventions relate to a strategy for incorporation of a novel chemical, coniferyl ferulate, into lignin. Coniferyl ferulate introduces an ester bond between the lignin and cellulose that is easy to cleave using alkaline chemicals. As a consequence, crops and plant materials with this modification would be better feedstocks for the extraction of cellulose and other polysaccharide polymers for use in pulp and paper production and cellulosic biomass-based biofuels.

MSU is offering genes and enzymes for incorporation of coniferyl ferulate into lignin. Additionally, a gene for use in blocking a side pathway present in grasses is available. This gene may be used to block this pathway, thereby diverting more substrate to an engineered coniferyl ferulate pathway in grasses. The coniferyl ferulate genes have been validated in a model system and are currently being tested in poplar.

Key Benefits

Improved feedstock for pulp and paper production: Transgenic trees with coniferyl-ferulate modified lignin have the potential to provide a substantially better feedstock for use in the Kraft process. It is expected that the altered lignin will reduce both energy and chemical requirements for pulping.
Better cellulosic biomass feedstock: Wood, dedicated energy crops, or crop residues with altered lignin could serve as better feedstocks for cellulosic biofuels by providing less expensive and more efficient extraction of fermentable sugars, particularly in processes involving ammonia or other alkaline pretreatment. It is expected that the altered lignin will reduce energy and chemical and enzyme requirements for biomass processing.
Improved lignin polymer extracts: Improved lignin may be extracted as longer polymers, which makes the improved lignin useful as a chemical substrate for carbon fiber production and other uses.

Applications