The technology could be used first for cheaper fermentation. One of the biggest industrial applications of fermentation is the production of plastics precursors such as succinic acid, and food additives such as citric acid. But these acids need to be counteracted by adding large quantities of base materials, such as calcium hydroxide, which are then converted in the process to waste products such as gypsum.
David Dodds, president of Dodds and Associates, a longtime industry consultant, says the calcium hydroxide treatment is the most expensive part of fermentation, with the possible exception of the costs of the sugar needed to feed the organisms. The new tool eliminates the need to add calcium hydroxide altogether by precisely controlling acidity, he says.
The Argonne technology also makes continuous production possible. In conventional fermentation, organisms are grown in a tank where they excrete a product until it reaches a concentration that is toxic to the organism. The contents of the fermentation tank are then poured out, and the process starts again. With the new EDI tool, the chemical product can be removed as it is made, so concentrations stay low. Microorganisms can continue producing chemicals for 10 times longer.
The new tool may also aid in engineeing organisms for new applications. It makes it unnecessary to use acid-resistant organisms, or organisms that can tolerate high concentrations of the chemical they produce.
The Argonne researchers have demonstrated the production and purification of chemicals at a small pilot-scale plant. The partnership with Nalco will make production versions of the system available for companies and other researchers. Although it’s not yet known precisely how much the equipment will cost for commercial production, Dodds says, “It looks to me that there will be significant cost savings.”