Patent ID: 9745601
Date: 2017-08-29
CPC Classifications: C12M,C12N,C12P,Y02E

Claim:
1. A system for producing isobutanol from genetically modified sulfur-oxidizing and iron-reducing bacteria (SOIRB) and iron oxidizing bacteria (IOB), said system comprising: a first bioreactor comprising sulfur-oxidizing and iron-reducing bacteria (SOIRB), wherein said SOIRB comprises a valine biosynthesis metabolic pathway that produces 2-keto acids and is genetically modified to include a 2-keto-acid decarboxylase gene and an alcohol dehydrogenase gene, said SOIRB being genetically modified so that said genes in said SOIRB convert said 2-keto acids to isobutanol; a first source of ferric iron in fluid communication with said first bioreactor; a source of water in fluid communication with said first bioreactor; a source of sulfur in fluid communication with said first bioreactor; a source of carbon dioxide in fluid communication with said first bioreactor; and an electrochemical reactor in fluid communication with said first bioreactor and a second bioreactor, wherein said electrochemical reactor is configured to directly reduce a second source of ferric iron provided by said first bioreactor to a second source of ferrous iron and to generate a stream comprising said second source of ferrous iron to be fed to said second bioreactor; said second bioreactor including iron oxidizing bacteria (IOB), wherein said IOB comprises a valine biosynthesis metabolic pathway that produces 2-keto acids and is genetically modified to include a 2-keto-acid decarboxylase gene and an alcohol dehydrogenase gene, said IOB being genetically modified so that said genes in said IOB convert said 2-keto acids to isobutanol; at least a first source of ferrous iron in fluid communication with said second bioreactor; a source of water in fluid communication with said second bioreactor; a source of oxygen in fluid communication with said second bioreactor; a source of carbon dioxide in fluid communication with said second bioreactor; a third source of ferric iron produced by said second bioreactor, wherein said second bioreactor is configured to feed said third source of ferric iron to said first bioreactor; and a third source of ferrous iron produced by said first bioreactor, wherein said first bioreactor is configured to feed said third source of ferrous iron to said second bioreactor.