9 Jan 2018
Researchers have discovered a gene that makes grass more digestible to livestock, which, in turn, means biomass can be more easily converted into biofuel.
Image: Rothamsted Research
Currently, plant biomass is predominately made up of cell walls with significant calorific value – an evolutionary advantage for survival spanning 60 million years – making it difficult for livestock to digest. As a result, the biomass produced by livestock is difficult to process into ethanol fuel when it reaches biorefineries.
However, the identification of the gene that causes cells walls to become more robust – known as feruloylation – has been named a ‘significant breakthrough’ for biofuel production.
Rowan Mitchell, co-team leader and plant biologist at Rothamsted Research, says ‘the impact is potentially global as every country uses grass crops to feed animals and several biofuel plants around the world use this feedstock.’
Researchers were able to produce genetically-modified plants in which a transgene supressed the expression of the endogenous gene that causes cell wall stiffness to 20% of normal levels, meaning the biomass produced was less feruloylated and easier to digest.
‘We identified grass-specific genes as candidates for controlling cell wall feruloylation 10 years ago, but it has proved very difficult to demonstrate this role although many labs have tried,’ says Mitchell. He notes that increased feruloyation can decrease digestibility – a key factor in determining how cost-effective it is to produce the biofuels from biomass.
This discovery could be a huge boost for the biofuel industry, an expanding area of research and development in Brazil. ‘Economically and environmentally, our livestock industry will benefit from more efficient foraging and our biofuels industry will benefit from biomass that needs fewer artificial enzymes to break it down during the hydrolysis process,’ says Hugo Molinari, the team’s other co-leader and Director of Research at the Laboratory of Genetics and Biotechnology, Embrapa Agroenergy, Brazil.
According to Mitchell, the suppression of the endogenous gene has no effect on a plant’s ability to produce biomass. Next, the group will build on this work to identify which gene facilitates the feruloyation process, which would make the biofuel method even more efficient, he says.
With billions of tonnes of biomass produced each year, this cost-effective breakthrough could help the biofuel industry contribute to a shift away from fossil fuels in the energy market.
By Georgina Hines