Ural Scientists Propose to Create Citric Acid Using Microorganisms

09:09, September 28, 2022

The new technology will solve two problems at once: environmental and import substitution

New scientific development will help to create Russia's own production of citric acid, which is currently fully imported. The new method is more technologically advanced and environmentally friendly, as it involves more rational use of microscopic mushrooms for biosynthesis of acid from waste sugar production or products of deep processing of grain. It also avoids large amounts of waste, wastewater and gas emissions. Aleksey Byuler from the UrFU Research Laboratory "Mathematical Modeling in Physiology and Medicine Based on Supercomputers" told about it on the air of the radio "Komsomolskaya Pravda".

In Russia, the traditional method of citric acid extraction from beet molasses using calcium citrate was used for citric acid production. This led to the formation of significant amounts of waste production: 1 kg of the obtained product had 2 kg of gypsum waste. Such gypsum is not applicable to construction purposes, and its processing requires a lot of energy, so all the gypsum was usually sent to waste, which created a serious impact on the environment. For this reason the only Russian plant producing citric acid was shut down several years ago. A new linear method using membrane (ultrafiltration) and electrodialysis technologies proposed by the scientists will make it possible to synthesize and isolate citric acid without harming the environment.

"Our technology is effective because we offer a plaster-free production technology, where special membranes and electrodialysis will be used to separate the citric acid. Through separation by membrane systems and further under the force of an electric field, the citric acid from the fermented solution is taken out into a separate stream, then concentrated and crystallized. The active biomass-producer is then fed back into the citric acid synthesis process. Under current conditions, with the help of this technology, we will not only solve the problem of reducing the amount of waste, but also contribute to the import substitution of such a sought-after product," explains Aleksey Byuler.

Citric acid is one of the main natural preservatives used in most canned foods, as well as dry mixes, fizzy drinks, and processed cheeses. In addition, a large percentage of the acid's use is in the industrial sector. For example, in oil production, it replaces hydrochloric acid and sulfuric acid for cleaning wells as a more environmentally friendly product. The scientist also notes that today the price of citric acid is high, so using electricity for its production would be economically profitable.

Reference

For industrial production of citric acid, molasses, a waste product from sugar production, is used as a substrate. Molasses contains non-sugars from sugar beet juice or sugar cane. The traditional method of citric acid extraction includes its precipitation with milk of lime followed by dissolution of calcium citrate with sulfuric acid, separation of calcium sulfate from the solution by filtration and extraction of citric acid from the solution by decolorization, desalting, evaporation, crystallization and drying.

This method of citric acid production produces large quantities of liquid effluents containing mineral acids and salts and simultaneously accumulates large quantities of solid waste (gypsum, waste coal, etc.). As a result, the technology becomes cumbersome and time-consuming.

The news article was translated by UrFU International Marketing Office
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