Barley straw shows potential as transport biofuel raw material

The hemicellulose sugars of barley straw can be effectively fermented into biobutanol when starch is added during the pretreatment or fermentation process, according to a study from the University of Eastern Finland.

Seeking to find alternatives to ethanol as a fuel, the study established optimal pretreatment conditions for turning straw lignocellulose and barley starch into fermentable sugars that can be used in the production of biobutanol. The hemicellulose sugars of barley straw (eg, xylose) released during pretreatment can be effectively fermented into biobutanol when starch is added to the fermentation broth.

The study found that the cooperation of xylanase and surfactants with cellulase during the hydrolysis of straw significantly increased the efficiency of cellulose utilisation in butanol fermentation. Moreover, the pretreatment liquor of fresh barley silage was efficiently used for butanol fermentation, indicating the feasibility of green field biomass preservation via a silage technique in biorefining processes.

In recent years, climate change has attracted widespread interest in biorefining and, in particular, the transport of biofuels production. Butanol as a competitive renewable biofuel is superior to ethanol in many aspects, with higher energy density, lower volatility and hygroscopicity and less corrosion to existing infrastructure. Importantly, it can be directly used in automobile engines without modification.

At present, sugar- or starch-based biomass (sugarcane molasses, corn and wheat) are the main feedstocks for butanol production. The climatic and social sustainability of large-scale fuel production from these raw materials is under wide-ranging debate. The possible solution for obtaining enough fermentable substrates is the efficient utilisation of the plentiful lignocellulosic biomass available on Earth. Barley has been regarded as a good supplement to corn biofuel production, as well as a replacement for the production of biofuels.

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