Can bacteria improve air transport?

Rapid social and industrial development of our civilization entails huge demand for energy. Its classic sources, such as oil, gas and other fossil fuels, are no longer sufficient. For many years, scientists have been trying to find an alternative to those fuels, looking for solutions in the biotechnological acquisition of the so-called green energy from organic waste. Recently, waste management has seen a trend of recovery of raw materials such as bioplastics, biofuels and other biochemical compounds from waste streams.

One of the valuable organic raw materials that can be successfully used for the production of biofuels is caproic acid. It is an organic carboxylic acid with many properties potentially useful for the pharmaceutical, cosmetics and chemical industries. But its greatest potential is seen in the production of biofuels, due to its high calorific value. This acid is currently produced on a large scale from coconut or palm oil. But it turns out that caproic acid can be successfully obtained using microorganisms.

Research on that process is conducted by a team led by Prof. Piotr Oleśkowicz-Popiel from the Poznań University of Technology. In an article recently published in Green Chemistry (DOI: 10.1039/c8gc01759j) the scientists describe the possibility of stable and efficient recovery of caproic acid from a single raw material, acid whey (a dairy waste), in a biotechnology process in an anaerobic reactor.

"The research that we describe in this article is more than a year of hard laboratory work, during which we managed to develop optimal conditions for obtaining caproic acid in a one-stage technological process using only one raw material" - emphasises the project leader.

Until now, capronic acid production has been described as a two-stage process requiring additional substrates, for example ethanol. The process modification proposed by the team from Poznań is a cheap and effective alternative to the previous procedure.

What does the production process involve? At the beginning, a bacterial sediment from methane fermentation chambers is introduced into the reactor to allow the bacteria that produce caproic acid to develop by skilfully manipulating the technological parameters. The biotechnological process of acquiring caproic acid has to be carried out at a slightly acidic pH, thus excluding the bacteria responsible for methane production from operation, and giving "the floor" in the reactor to those bacteria whose presence is desirable and ensures the production of caproic acid. Researchers have created a specialized cluster of bacteria that effectively carry out the selected process.

"It is worth noting that thanks to its high calorific value, caproic acid may be used as an aviation biofuel" - adds the scientist. "Of course, after producing the raw material, it must be separated from the post-reaction mixture. We are working on that now. Then this compound must be properly chemically modified to meet the aviation fuel standards, but there is a good chance that caproic acid will be the future of biofuels for this transport sector" - he says.

PAP - Science in Poland, Dr. Aleksandra Ziembińska-Buczyńska

Dr. Aleksandra Ziembińska-Buczyńska is a microbiologist at the Silesian University of Technology. Since 2017, she has been managing the Silesian University of Technology Science Promotion Centre. In 2015, she took third place in the third Polish edition of FameLab. She hosted the show "Inventors of the Future" on CANAL+ DISCOVERY, in which she presented Polish inventions and discoveries expected to change our world in the near future. She is a finalist of the Science Promoter 2017 competition co-organized by PAP - Science in Poland and the Ministry of Science and Higher Education.

The article is one of the results of the program Spokespersons of Science, organized by the Copernicus Science Centre and the British Council Foundation. The program facilitates establishing cooperation between scientists who promote knowledge and science journalists.

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