Baseload, Bioenergy

National Lab Study Seeks Best Biocatalysts for Biofuel Production

A new comparative study from the Oak Ridge National Laboratory (ORNL)-based BioEnergy Science Center has found that the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production.

ORNL said in a Jan. 14 statement that a team of researchers from five institutions analyzed the ability of six microorganisms to solubilize potential bioenergy feedstocks such as switchgrass that have evolved strong defenses against biological and chemical attack. According to ORNL, solubilization prepares the plant feedstocks for subsequent fermentation and, ultimately, use as fuel. A paper on the comparative study was published in Biotechnology for Biofuels.


The microbe Clostridium thermocellum (stained green), seen growing on a piece of poplar biomass, is among several microorganisms recently evaluated in a BioEnergy Science Center comparative study. Image by Jennifer Morrell-Falvey, Oak Ridge National Laboratory.

“Starting with nature’s best biomass-solubilizing systems may enable a reduction in the amount of nonbiological processing required to produce biofuels,” ORNL coauthor Brian Davison said. “We’re asking the question – what are nature’s best biocatalysts?”

Their analysis demonstrated that under carefully controlled conditions, a microbe called Clostridium thermocellum is twice as effective as fungal enzymes used by industry today. The researchers also tested the different microbes’ performance with minimal pretreatment of the plant materials, indicating it may be possible to reduce or eliminate use of heat and chemicals that make the feedstock accessible to biological processing. 

“Eliminating both enzyme addition and conventional pretreatment is a potential game-changer,” Dartmouth engineering professor Lee Lynd said. Lynd is the study’s corresponding author. 

The researchers also note that the study was designed to provide indications of intrinsic capability and performance under industrial conditions. ORNL said that they hope the findings will guide the development of advanced processes to lower costs and improve the efficiency of commercial biofuel production.

“One of the directions that this study leads is that we might have to go out into nature to find the best bugs, even if they are not the ones we’re most familiar with,” Lynd said. “A major thrust in BESC is that we exclusively focus on these non-standard microorganisms that bring strong biocatalytic abilities to the table, rather than focusing on well-known microorganisms.”

ORNL said that the research team also considered the use of mechanical disruption techniques, such as milling to complement the microorganisms’ biological breakdown.