US scientists develop method to customise microbes for biofuel production
Scientists at the US Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) have devised a method to insert genes into a range of microorganisms that would previously reject foreign DNA, with the objective of creating custom microbes for better biofuel production.
A team at the DOE Centre for Bioenergy Innovation (CBI) at ORNL are using the power of microbes – the most abundant life forms on Earth – to turn non-food biomass into biofuels and bioproducts.
In order to increase conversion efficiency, microbes are needed that can break down cellulose and ferment it into biofuels using just one set of reactions. This approach, which is known as consolidated bioprocessing (CBP), improves the economics of biofuels production.
The CBI have attempted to create custom microbes to achieve greater yields of biofuels. The aim was to create microbes that eat cellulose to produced desired fuels and which thrive in high-temperatures without oxygen.
However, microbes have developed defence mechanisms to prevent the introduction of target traits, which guard them against accidently copying foreign DNA. Adam Guss, genetic and metabolic engineer in ORNL’s biosciences division and his team have, however, demonstrated a way to leverage this defence system to coax microbes into accepting bioengineered DNA as their own.
Using two sequencing methods, the scientists first identified a microbe’s signature sequences and the enzymes that methylate them. Then they expressed the enzymes, known as methyltransferases, in E. coli. With the right methyltransferases in place, E. coli are able to make copies of DNA with the expected methylation patterns, ensuring the target microbe would accept and use the new DNA.
The gene that the researchers inserted into Clostridium thermocellum ATCC27405, a CBP organism that has proven difficult to transform, was shown to function as anticipated. Additionally, Guss and his team have had similar success with 10 other species so far – all of which were previously unamenable to genetic engineering.
“The more we do it, the more we learn,” Guss explained. “It becomes more and more rapid and reliable as well.”
“What Adam and his team have done is to remove one of the major stumbling blocks to transforming these organisms,” added CBI chief scientist Brian Davison. “This opens the door to take these microbes with really tough-to-replicate traits and be able to tune them to do more of what we want, such as increasing biofuel yields.”
A team at the DOE Centre for Bioenergy Innovation (CBI) at ORNL are using the power of microbes – the most abundant life forms on Earth – to turn non-food biomass into biofuels and bioproducts.
In order to increase conversion efficiency, microbes are needed that can break down cellulose and ferment it into biofuels using just one set of reactions. This approach, which is known as consolidated bioprocessing (CBP), improves the economics of biofuels production.
The CBI have attempted to create custom microbes to achieve greater yields of biofuels. The aim was to create microbes that eat cellulose to produced desired fuels and which thrive in high-temperatures without oxygen.
However, microbes have developed defence mechanisms to prevent the introduction of target traits, which guard them against accidently copying foreign DNA. Adam Guss, genetic and metabolic engineer in ORNL’s biosciences division and his team have, however, demonstrated a way to leverage this defence system to coax microbes into accepting bioengineered DNA as their own.
Using two sequencing methods, the scientists first identified a microbe’s signature sequences and the enzymes that methylate them. Then they expressed the enzymes, known as methyltransferases, in E. coli. With the right methyltransferases in place, E. coli are able to make copies of DNA with the expected methylation patterns, ensuring the target microbe would accept and use the new DNA.
The gene that the researchers inserted into Clostridium thermocellum ATCC27405, a CBP organism that has proven difficult to transform, was shown to function as anticipated. Additionally, Guss and his team have had similar success with 10 other species so far – all of which were previously unamenable to genetic engineering.
“The more we do it, the more we learn,” Guss explained. “It becomes more and more rapid and reliable as well.”
“What Adam and his team have done is to remove one of the major stumbling blocks to transforming these organisms,” added CBI chief scientist Brian Davison. “This opens the door to take these microbes with really tough-to-replicate traits and be able to tune them to do more of what we want, such as increasing biofuel yields.”
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