GM Switchgrass Delivers

The researchers at Samuel Roberts Noble Foundation in Oklahoma modified the lignin content, producing a variant with 38% more bioethanol and requiring 4-5 times less cellulase enzyme for the pretreatment step used to produce sugars from the biomass.Chunxiang Fu, from the Samuel Roberts Noble Foundation, reporting in PNAS, states: 

“The transgenic plant materials require less severe pretreatment and much lower cellulase dosages to obtain ethanol yields equivalent to yields in controls. These transgenic switchgrass lines and the approach are valuable for developing improved cultivars of biofuel crops.”

Switchgrass is one of the crops being put forward as a replacement feedstock for bioethanol production that doesn’t compete with food production. The plant itself can grow to 10 feet high and has “pencil thick” stems. It grows quickly and uses water and nutrients quite efficiently, one of the reasons why it is often considered for growth on marginal land rather than land used currently for conventional agriculture. It typically has a lifespan of roughly ten years and can be harvested multiple times during that time. Sometimes it is used by farmers for other applications than as a biofuel feedstock; sometimes switchgrass is used to improve the quality of the soil, prevent soil erosion or as animal feed. Getting the most fuel possible from each planted acre is clearly of value to all involved, while enzymes used for the pretreatment stage often make up a significant part of the overhead costs of running the process.