Clostridium thermocellum increases biofuel production efficiency

Decomposing agricultural crops and agricultural wastes with microorganisms to produce ethanol is the main direction of biofuel research. US researchers recently discovered a gene that is expected to help increase the efficiency of microbial production of ethanol and lower production costs.

A team of researchers from the US Department of Energy’s BioEnergy Science Center recently issued a press release saying that newly discovered genes determine the bacteria’s tolerance to ethanol in Clostridium thermocellum, a bacterium used to produce fuel ethanol.

Clostridium thermocellum can ferment and degrade cellulose to produce ethanol. Because it can self-manufacture the enzymes needed for the degradation process, it does not require the addition of expensive catalysts and has great application value in biofuels. However, ethanol is a product of bacterial metabolism, and bacteria have a certain tolerance to ethanol. If you can develop strains that are more tolerant to ethanol, you can produce higher concentrations of ethanol, thereby reducing production costs.

The researchers sequenced the genomes of two strains of Clostridium thermocellum. One is a strain that can adapt to ethanol, and the other is a wild strain that does not have this ability. Comparing the genomes of the two strains, it was found that a single gene determines the strain's tolerance to ethanol. Transplanting a specific mutant version of this gene will allow the wild strain to gain tolerance. This finding is surprising because ethanol tolerance is a complex feature that people used to guess that it should be controlled by multiple genes.

The current industrial production of fuel ethanol is mainly based on corn and other grains as raw materials. If cellulose is used effectively to produce ethanol, raw materials can be expanded to straw, sawdust, grass, etc. to reduce food consumption.