Research discovers process to convert corn waste into sugar for biofuel

Producing sugar from corn stalks and other crop waste can be turned into sustainable biofuels, according to new research.

Scientists at Washington State University (WSU) have used ammonium sulphite-based alkali salts to convert corn stover — leftover corn stalks, husks, and other residues — into low-cost sugar to produce biofuels and bioproducts, making the process more economically feasible.

Bin Yang, Lead Investigator at WSU, said inexpensive sugar is the key to commercial success for new technologies that make fuels and useful products from renewable biomass.

Yang and collaborators at the University of Connecticut, the National Renewable Energy Laboratory (NREL), the USDA Forest Products Lab in Madison and Wisconsin sought a cost-competitive way to efficiently turn cellulosic biomass, traditionally residues from corn and other tough, lignin- and cellulose-rich crops, into sugar.

According to the research, biomass is abundant and cheap and holds great potential as a source of energy and valuable chemicals.

However, due to the difficulties in breaking down complex structural molecules like cellulose and lignin, its high processing cost remains a major challenge.

Yang says it’s essential to develop new pretreatment technologies that can better break down complex polymers and produce affordable sugars to unlock this resource’s vast potential benefits.

The process pretreats corn stover with potassium hydroxide and ammonium sulphite at mild temperatures, allowing enzymes to break down cellulosic polymers into sugar, which can then be fermented into biofuels and bioproducts without the need for chemical recovery.

Researchers calculated that, by offsetting the cost of production through byproduct uses or sales, the resulting sugar could be sold for as low as 28 cents per pound, making it competitive with low-cost imported sugar.

Yang says this patent-pending process produces high-quality fermentable sugar for the biorefinery — the industrial process turning plant matter into fuel — and fertiliser that can replenish soil nutrients for farmers.

Xiaowen Chen, Principal Investigator at NREL, said that in the next phase, the team will advance its pretreatment technology on a pilot scale.

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