Trait Gene for Highly Digestible Forage

Introduction

Production of fuels and value-added chemicals from plant biomass often requires pretreatment of the biomass. Pretreatment increases the capital equipment needs and costs of the final product. Additionally, the use of seeds as a feedstock has been controversial, with some claiming that use of seeds for chemical production is increasing the cost of food. What is needed is non-food plant material such as stems or leaves that requires less pretreatment.

Description of Technology

This technology is a method and composition for improving the digestibility of plant biomasses by increasing the methylesterification of homogalacturonan (HG) in the plant cell wall. Methylesterification is increased via the overexpression of certain methyltransferases. The methyltransferases act on HG molecules before they are delivered to the apoplast, thus not interfering with the amount of de-esterified HG in the cell wall. Presence of highly demethylesterified pectin improves digestibility of plant biomasses while maintaining normal amounts of esterified HG prevents negative effects on the plant’s mechanical strength and growth. Ultimately, this technology reduces cost of pretreatment in terms of money and time, leading to more efficient biofuel or green chemical production, improved forage crops, and more easily pulped trees.

Key Benefits

Normal plant mechanical strength—the level of de-esterified HG in the cell wall is not interfered with. Therefore, methyltransferase overexpression does not affect the mechanical strength and growth of the plant.
Reduces pretreatment costs—methyltransferase-overexpressing plants are more easily digested by cell wall degrading enzymes, which lowers the need for pretreatments requiring temperatures, toxic acids, peroxides, ammonia, or mechanical disruption and therefore lowers biomass pretreatment costs.
Increased biomass—overexpressing plants are larger than wild-type plants.

Applications