Chemicals from the air
Genetically engineered bacteria turn carbon dioxide into industrial chemicals
Marina Astvatsaturyan, Echo of Moscow
Genetically modified bacteria produce substances present in solvents and disinfecting liquids from carbon dioxide and carbon monoxide in the air, therefore, compared with traditional industrial production methods, the proposed biotechnological cycle is characterized by negative carbon emissions, according to a press release from Oak Ridge National Laboratory Carbon-negative platform turns waste gases into valuable chemicals.
Conversion of simple carbon and oxygen compounds into acetone – VM.
Michael Köpke from LanzaTech in Illinois and his colleagues were looking for enzymes from strains of ethanol-producing bacteria of the Clostridium autoethanogenum species that would allow microbes to produce acetone instead of ethanol, used in solvents and nail polish remover. Having discovered them, scientists combined the genes responsible for the synthesis of these enzymes in one organism.
They produced a similar thing for isopropanol used in disinfectants. The engineered bacteria use carbon dioxide from the air as a substrate for the production of acetone and isopropanol. "Imagine a process similar to fermentation of wort in brewing, but instead of yeast, which eats sugar to produce alcohol, we have a microbe that eats carbon dioxide," explains Koepke.
Having increased the scale of the initial experiments by 60 times, the authors of the study found that the process keeps 1.78 kilograms of carbon per kilogram of acetone produced and 1.17 kilograms per kilogram of isopropanol from being released into the atmosphere. When these compounds are produced in a conventional way using fossil fuels, emissions are 2.55 kilograms and 1.85 kilograms of carbon dioxide per kilogram of acetone and isopropanol, respectively. According to scientists, the widespread implementation of their proposed method is equivalent to reducing greenhouse gas emissions by 160 percent.
The method of producing compounds necessary for humans through bacteria can become an environmentally reliable way of using gas waste from processes such as, for example, steel production. Scientists tested their genetically engineered clostridia by connecting a bioreactor with a culture of microbes to the exhaust pipe of a steel mill, and saw the active absorption of carbon dioxide with the formation of acetone and isopropanol.
"Our approach can become the basis for future similar developments, and it will accelerate the creation of other chemical compounds in the same carbon-negative way and on a renewable basis," Koepke quotes New Scientist. The results of the study are published in Nature Biotechnology (Liew et al., Carbon-negative production of acetone and isopropanol by gas fermentation at industrial pilot scale).
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