Cornell University biological engineers have deciphered the cellular strategy to make the biofuel ethanol, using an anaerobic microbe feeding on carbon monoxide – a common industrial waste gas.
“Instead of having the waste go to waste, you make it into something you want,” said Ludmilla Aristilde, assistant professor in biological and environmental engineering. “In order to make the microbes do our work, we had to figure out how they work, their metabolism.”
Aristilde collaborated with her colleague Lars Angenent, professor of biological and environmental engineering, on the project. She explained, “The Angenent group had taken a waste product and turned it into a useful product.”
To make biofuel from inorganic, gaseous industrial rubbish, the researchers learned that the bacterium Clostridium ljungdahlii responds thermodynamically – rather than genetically – in the process of tuning favorable enzymatic reactions.
Synthetic gas – or syngas – fermentation is emerging as a key biotechnological solution, as industrial-sized operations are looking to produce ethanol from their gaseous waste streams, according to Angenent, a fellow at Cornell’s Atkinson Center for a Sustainable Future. The scientists sought to grasp the physiological nature of the process: “These findings are important for the syngas fermentation community to design future strategies to improve production,” Angenent said.
UCLA biochemists have devised a way to convert sugar into a variety of useful chemical compounds without using cells
UCLA biochemists have devised a clever way to make a variety of useful chemical compounds, which could lead to the production of biofuels and new pharmaceuticals.
“The idea of synthetic biology is to redesign cells so they will take sugar and run it through a series of chemical steps to convert it into a biofuel or a commodity chemical or a pharmaceutical,” said James Bowie, a professor of chemistry and biochemistry in the UCLA College, and senior author of the new research. “However, that’s extremely difficult to do. The cell protests. It will take the sugar and do other things with it that you don’t want, like build cell walls, proteins and RNA molecules. The cell fights us the whole way.”
As an alternative, Bowie and his research team have developed a promising approach he calls synthetic biochemistry that bypasses the need for cells.
“We want to do a particular set of chemical transformations — that’s all we want — so we decided to throw away the cells and just build the biochemical steps in a flask,” Bowie said. “We eliminate the annoying cell altogether.”
The biochemists purified more than two dozen enzymes in particular combinations and concentrations, put them in a flask and added glucose. The enzymes and pathways, created in Bowie’s laboratory, are not necessarily found in nature. “When we don’t have to worry about keeping cells happy, it’s easier to rearrange things the way we want,” he said.
Now scientists have a new technique that avoids the expensive enzymes
Producing second-generation biofuel from dead plant tissue is environmentally friendly — but it is also expensive because the process, as used today, needs expensive enzymes, and large companies dominate this market. Now scientists have a new technique that avoids the expensive enzymes. The production of second generation biofuels thus becomes cheaper, probably attracting many more producers and competition, and this may finally bring the price down.
The world’s need for fuel will persist, also when Earth’s deposits of fossil fuels run out. Bioethanol, which is made from the remains of plants after other parts have been used as food or other agricultural products, and therefore termed “second generation,” is seen as a strong potential substitute candidate, and countries like the United States and Brazil are far ahead when it comes to producing bioethanol from plant parts like corn or sugar canes. Corn cubs and sugar canes are in fact plant parts that can also be used directly as food, so there is a great public resistance to accept producing this kind of bioethanol. A big challenge is therefore to become able to produce bioethanol from plant parts, which cannot be used for food.
“The goal is to produce bioethanol from cellulose. Cellulose is very difficult to break down, and therefore cannot directly be used as a food source. Cellulose is found everywhere in nature in rich quantities, for example in the stems of the corn plant. If we can produce bioethanol from the corn stems and keep the corn cubs for food, we have come a long way,” says Per Morgen, professor at the Institute of Physics, Chemistry and Pharmacy, University of Southern Denmark.