UC Berkeley and Lawrence Berkeley National Laboratory, or Berkeley Lab, researchers studying a common wood-feeding beetle uncovered a complex digestive system that can turn wood into useful biofuels, according to a study released Monday.
The Odontotaenius disjunctus beetle has four specialized regions for anaerobic and aerobic digestion, according to Jennifer Pett-Ridge, principal investigator of the study’s larger project. These digestive regions allow the beetle to convert wood into biofuels such as acetate, hydrogen and ethanol while minimizing methane waste product.
“The cool thing mentioned in this paper is that the beetle is capable of encouraging microbes to turn biomass into useful products while limiting waste products like methane,” said Pett-Ridge.
According to lead study author and Berkeley Lab research scientist Javier Ceja-Navarro, the main findings of the study uncovered how the beetle survives on a low-nutrient diet. The beetle’s digestive system includes four connected compartments, assisted by microorganisms, that specialize in the various steps of wood decomposition.
The coevolution of the beetle and its gut microorganisms has the potential to create a better bioreactor, according to Pett-Ridge, who added that fuel for running cars and heating could eventually come from food waste and biomass.
“We could take some of the specific enzymes that are inside the insect’s gut and find out whether they are more effective or effective in new ways compared to what we currently use in the biofuel industry,” said Pett-Ridge.
The project, which commenced in 2009, began with a partnership between Louisiana State University professor Meredith Blackwell and other researchers. The researchers were interested in learning about the microbial systems of “complex metabolisms” in small spaces, according to Pett-Ridge.
She added that Blackwell studied the passalid beetle for a long time, analyzing its use of fungi to make ethanol — a similar process to brewing beer. After five to six years of studying the beetle’s gut contents, researchers found other microorganisms in addition to the fungi.
Studying the various microorganisms in the gut was not easy because researchers gathered large numbers of DNA sequences from microorganisms in the beetles’ digestive systems, according to Pett-Ridge. This was especially difficult due to the reconstruction of the genomes afterward.
Thought there have been similar studies conducted on termites, their digestive systems are much more simple than the beetle’s, said Pett-Ridge.
According to Ceja-Navarro, the researchers want to use what they learn to design a next generation process of turning lignocellulose, a compound found in wood, into biofuels.
“We envision the design of bioreactors that will mimic the environmental and microbial conditions in the beetle gut,” said Ceja-Navarro in an email. “In this way, we will be using the innovation provided by nature to combine biochemical processes that are otherwise incompatible.”
