Tweaking corn genes to boost biofuel yields

Purdue University researchers are probing genes that control the tough cell walls of maize and switchgrass.

The idea is simple: Genetically modify those genes so corn and switchgrass plants can produce more biomass, which leads to an abundance of sugars that can be efficiently processed into biofuels (see World Bank says food prices hit by biofuels).

The scientists, Nick Carpita and Maureen McCann, plan to analyze the plant genes for several factors, including breeding success, genome sequences and cell-wall composition.

The scientists have chosen to study these grasses because they require low inputs of mineral nutrients to grow. By improving the cell wall composition, the researchers think they’ll be able to constrain cell size and shape and thus impact the overall biomass yield.

The researchers said plants devote 10 percent of their 2,500 genes to construction and dynamic arrangement. The challenge is that no one knows much about how this 10 percent functions (see Aurora Biofuels lands $20M in Series B).

“Our focus is not just cell-wall genes, but those that control growth and development as well as regulate the rates and extent of cell wall deposition,”  Carpita told the Cleantech Group. 

The Purdue project aims to assemble gene networks, but Carpita said systems-biologists can use those findings to improve plant productivity.

The researchers have already made some headway on their studies. The team has already completed a large study funded by the National Science Foundation Plant Genome Program to study gene family structures, Carpita said.

The Purdue researchers have a three year research $1.2 million grant from the U.S. Department of Energy/U.S. Department of Agriculture research program, which provides funds for accelerating development of biofuels from plants.

 Several other research efforts are underway to study ways to more easily produce fuel from the large amount of cell walls that comprise a plant's biomass. Currently, there are three major Department of Energy projects working on this research at three laboratories: University of Wisconsin, Oak Ridge National Laboratories in Tennessee, and Lawrence Berkeley National Labs in Berkeley, Calif.

In the United States, ethanol is mainly made from corn because starch in the kernels is easily converted to sugar for fermentation to the alternative fuel.

Much of today’s ethanol production comes from starch-rich kernels. Targeting ways to produce more fuel from the plant’s biomass and cell walls is considered a more efficient long term approach, according to the Purdue researchers.

In June 2007, U. S. Department of Energy announced plans to invest up to $375 million in three new Bioenergy Research Centers. The Centers are intended to accelerate basic research in the development of cellulosic ethanol and other biofuels, advancing President Bush’s Twenty in Ten Initiative. The initiative seeks to reduce U.S. gasoline consumption by 20 percent within 10 years through increased efficiency and diversification of clean energy sources.