Replacing an energy-dense liquid like petroleum with alternative fuels is easier said than done. From the hidden carbon footprint of ethanol to some serious questions about the sustainability of hydrogen fuel cells, many replacement options come with their own significant environmental baggage.

Nevertheless, if we are going to reverse the worst impacts of climate change, we're going to have to find our way to low-carbon fuels fast. One potential path forward lies in the conversion of the sugars found in plants into hydrogen fuel using novel or engineered enzymes. Until recently, however, yields of hydrogen from such efforts were low and costs were too high. In 2013, however, a team of Virginia Tech researchers published research suggesting a potential breakthrough on this front, having developed a means to generate low-cost hydrogen fuel from almost any source of biomass. 

Here's how Virginia Tech News explained the significance: "Our new process could help end our dependence on fossil fuels,” said Y.H. Percival Zhang, an associate professor of biological systems engineering in the College of Agriculture and Life Sciences and the College of Engineering. “Hydrogen is one of the most important biofuels of the future.”

Zhang and his team have succeeded in using xylose, the most abundant simple plant sugar, to produce a large quantity of hydrogen that previously was attainable only in theory. Zhang’s method can be performed using any source of biomass.

The process generates almost no greenhouse gases, unlike previous energy-intensive methods for generating hydrogen, such as the use of natural gas. It uses enzymes artificially isolated from microorganisms that typically thrive at extreme temperatures to convert xylose, the second most abundant plant sugar, into hydrogen. Researchers suggested they could see the technology commercialized in as little as three years. Previous research by James Swartz of the Department of Chemical Engineering and Department of Bioengineering at Stanford University has suggested that enzymatic hydrogen production could yield 10-fold higher fuel value conversions than current biomass-to-ethanol technologies. 

Of course any switch to hydrogen fuel cells will have to compete with the rapid advance of battery electric vehicles and solar power, both of which have gone from marginal technologies to serious contenders in just a few short years. 

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