Microorganism Could Support Development of Low-Cost Biofuel Production Process

Scientists from BioEnergy Science Center (BESC) at the Department of Energy have conducted a proteomics study on Caldicellulosiruptor obsidiansis, a bacterium discovered by them in a Yellowstone National Park’s hot spring for production of advanced biofuels.

The BESC scientists are expanding their initiatives toward commercially feasible ethanol or biofuel production from crops like switchgrass.

Currently, ethanol production depends on the application of costly enzymes that break complex plant materials to produce sugars. These sugars are later fermented to produce ethanol. Consolidated bioprocessing is recommended as a cheaper option for the current process. The process employs microorganisms, which are resistant to very high temperatures, to split up the resistant biomass materials.

The bacterium breaks down plant materials such as leaves and sticks. The scientists are exploring to transfer this ability to ethanol production tanks. To achieve this objective, the research team performed a comparative study of proteins taken from C. obsidiansis that is grown on four carbon substrates, varying from a simple sugar to highly complex substrates like pure cellulose and then finally to switchgrass. The use of carbon sources enabled researchers to compare how the microorganism reacted to complex materials.

The study has revealed that growth on switchgrass induced the bacterium to produce a wider set of proteins. These proteins deal mainly with hemicellulose substances of the plant, which include extracellular solute-binding proteins and hemicellulose-targeted glycosidases. These two substances work together to break down the organic material into sugars and transfer them into the cell. After transferring to the cell, C. obsidiansis will further process the sugars into useful energy through secretion of certain enzymes. Thus, the microorganism could play a key role in the development of low-cost biofuel production process.