Researchers at the BioEnergy Science Center (BESC) at the Oak Ridge National Laboratory (ORNL) are looking beyond the usual suspected bugs in the search for microbes that can efficiently break down inedible plant matter for conversion to biofuels. A new comparative study finds the natural abilities of unconventional bacteria could help boost the efficiency of cellulosic biofuel production.
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. Solubilization prepares the plant feedstocks for subsequent fermentation and, ultimately, use as fuel.
ORNL coauthor Brian Davison explained, “Starting with nature’s best biomass – solubilizing systems may enable a reduction in the amount of nonbiological processing required to produce biofuels. We’re asking the question, what are nature’s best biocatalysts?” The idea is to substitute organic bio-solutions in place of costly brute force heat and organic chemistry.
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,” said Dartmouth engineering professor Lee Lynd, the study’s corresponding author.
The researchers note that the study was designed to provide indications of intrinsic capability and performance under industrial conditions. They hope their 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.”
The research team also considered the use of mechanical disruption techniques such as milling to complement the microorganisms’ biological breakdown.
Switchgrass, poplar and other crops have been on the idea list for biofuels for a long time. So far only corn stubble has made any progress and those are demonstration plants with little expectation of much growth. The cellulosic field is in need of a breakthrough in breaking down those tough plant molecules to get to the sugars.
Thinking outside of the known box is welcome and necessary. With one new bug in the inventory there is progress. Industry is ready. Consumers have accepted biofuels in proportion with petroleum and the petroleum industry is busy trying to stay afloat in business in the face of its own great success. The food crowd may have realized they were fighting a phantom over ethanol, blowing tens of millions of dollars.
Its tough to get support as sugarcane, corn, wheat and crude oil are all way too cheap for their industries to prosper. In less than half a generation energy from fuels have skyrocketed and collapsed.. The cycle will repeat. Lets hope the researches keep looking outside the known box so the next price skyrocket doesn’t fly so high.