Processes and systems for metabolite production using hydrogen rich C1-containing substrates
The invention is directed to a process for producing one or more fermentation product in a multi-stage process including an inoculation reactor and at least one bioreactor. The inoculation reactor is fed a C1-containing gaseous substrate containing a reduced amount of hydrogen. The hydrogen is reduced to increase the proportion of CO in the C1-containing gaseous substrate being provided to the inoculation reactor. The inoculation reactor ferments the CO-rich C1-containing gaseous substrate and produces an inoculum, which is fed to at least one bioreactor. The bioreactor receives the C1-containing gaseous substrate, which may or may not contain reduced amounts of hydrogen, to produce one or more fermentation product. By providing a CO-rich C1-containing gaseous substrate to the inoculation reactor, both the inoculation reactor and the subsequent bioreactor(s), are able to have increased stability and product selectivity.
1. A process for producing one or more fermentation products, the process comprising;
a. providing a CO-rich C1-containing gaseous substrate to an inoculation reactor comprising a liquid nutrient medium containing a culture of one or more C1-fixing microorganism;
b. fermenting the CO-rich C1-containing gaseous substrate to produce an inoculum;
c. passing at least a portion of the inoculum to a bioreactor system, the bioreactor system comprising at least one bioreactor containing a culture of one or more C1-fixing microorganism in a liquid nutrient medium;
d. passing an H 2 rich C1-containing gaseous substrate to the bioreactor system; and
e. fermenting the H 2 rich C1-containing gaseous substrate to produce at least one fermentation product.
2. The process of claim 1 , wherein the CO-rich C1-containing gaseous substrate comprises H 2 at an H 2 :CO molar ratio of less than 1:1.
3. The process of claim 1 , wherein the CO-rich C1-containing gaseous substrate comprises H 2 at an H 2 :CO molar ratio of less than 0.5:1.
4. The process of claim 1 , wherein the CO-rich C1-containing gaseous substrate comprises H 2 at an H 2 :CO molar ratio between 0.02:1 to 1:1.
5. The process of claim 1 , wherein the H 2 rich C1-containing gaseous substrate comprises H 2 at an H 2 :CO molar ratio of at least 1.1:1.
6. The process of claim 1 , wherein the H 2 rich C1-containing gaseous substrate comprises H 2 at an H 2 :CO molar ratio between 1.1:1 to 6:1.
7. The process of claim 1 , wherein the C1-fixing microorganism is a carboxydotrophic bacterium.
8. The process of claim 7 , wherein the carboxydotrophic bacterium is selected from the group consisting of Moorella, Clostridium, Ruminococcus, Acetobacterium, Eubacterium, Butyribacterium, Oxobacter, Methanosarcina , and Desulfotomaculum.
9. The process of claim 7 , wherein the carboxydotrophic bacterium is Clostridium autoethanogenum.
10. The process of claim 1 wherein the bioreactor system comprises one or more primary bioreactors linked to one or more secondary bioreactors.