When treated, cellulosic biomass can actually produce a mixture of pentose (5 chained carbon) and hexose (6 chained carbon) sugars, as well as glucose, galactose, D-xylose, mannose and L-arabinose. Saccharomyces cerevisiae is typical industrial yeast that offers high production, fast sugar consumption and ethanol tolerance. The only problem is, it cannot ferment pentose sugars.

The lack of helpful microorganisms that can convert the hexoses and pentoses effectively to ethanol is a major hindrance to the cost-efficient production of cellulosic ethanol through the process of fermentation.

Boles and his team had first screened and studied the choromosomal strain and obtained databases. They found out that they could actually clone and express successfully a highly reactive kind of xylose isomerase (XI) from the Clostridium phytofermentans, an anaerobic bacterium inS. cerevisiae. The new strain of XI offers more advantages in the modification of S. cerevisiae, compared to the previous XI’s that they used.

Boles is also the cofounder of the Swiss biofuel company, the Butalco Gmbh. He and his colleagues are now conducting researches on converting biomass to butanol by genetically modifying strains of yeast.