Microorganisms can sometimes produce chemicals and fuels as cheaply as conventional methods, while using sugar instead of petroleum. Technology developed by researchers at Argonne National Laboratories could help reduce the cost of production of chemicals or fuels made using microorganisms, and potentially increase the range of such materials. It does this, in part, by keeping the bugs alive for longer. The researchers recently announced that Nalco, a company based in Naperville, Illinois, will commercialize the technology.
The new tool uses an advanced form of electrodeionization (EDI), a technology used to make ultrapure water. The advanced EDI provides a better way to control the acidity of the solution in which an organism grows, and this helps optimize the microbe-driven production process. It also efficiently removes the chemicals that microorganisms make, allowing the process to run continuously. By creating a less harmful environment for growth, the tool could make it easier to engineer microorganisms for producing new chemicals.
In conventional EDI, resins pull charged molecules, or ions, out of a solution. An electric field then moves the ions to a membrane that allows the ions to pass but filters out other chemicals. The system can also control the acidity of the solution by using the electric field to split small amounts of water into more acidic or basic components, and then selecting one or the other to be removed through the membrane.
In a conventional EDI system, the resin takes the form of tiny beads, packed randomly so that there are often poor connections between them. There is a trade-off between the conductivity of the resin, which affects the efficiency of the system, and its porosity which affects how fast it can produce chemicals.
The Argonne researchers have developed what they call resin wafers, which combine multiple resins, binding agents, and additives to improve the conductivity and porosity of the material. The approach also keeps electricity costs low–just a few cents of electricity is needed to produce a pound of a chemical that sells for a dollar, says Seth Snyder, who is leading the project at Argonne.