Method of operation of fermentation of carbon monoxide and hydrogen containing gaseous substrate

1. A method of producing one or more alcohols from a gaseous substrate, the method comprising:

adding gaseous substrate comprising carbon monoxide (CO) and hydrogen (H 2 ) into an aqueous medium in a bioreactor, wherein the aqueous medium includes one or more anaerobic acetogenic microorganisms;

agitating the aqueous medium at an agitator speed of 10 to 1000 rpm;

measuring conversion of CO;

measuring conversion of H 2 ; and

increasing a flow rate of gaseous substrate into the bioreactor by a flow factor (proposed quantity of gaseous feed divided by current quantity of gaseous feed) of 1.05 to 2.0 when CO conversion in the bioreactor is 25 to 95%, H 2 conversion in the bioreactor is 25 to 95% and a difference between CO conversion and H 2 conversion in the bioreactor is 0% to 25%, wherein the agitator speed is increased when a second CO conversion is 0 to 25% and H 2 conversion is 0 to 25%

wherein if a concentration of acetic acid in the aqueous medium is less than about 2.5 grams per liter after reaching a cell density of at least 50% more than an initial cell density, then about 0.34 ml of a vitamin solution is added per liter of aqueous medium,

wherein the vitamin solution includes about 0.08 to about 1 μM biotin, about 0.12 to about 1.5 μM thiamin HCL, and about 0.15 to about 2 μM calcium d-pantothenate.

2. The method of claim 1 wherein the method includes adding a flow of nutrient medium into the bioreactor.

3. The method of claim 1 wherein the flow rate of gaseous substrates is increased between two consecutive increases in agitation speed.

4. The method of claim 1 wherein the flow rate of gaseous substrate is increased by 5% when H 2 conversion was greater than 45%.

5. The method of claim 1 wherein the flow rate of gaseous substrate is increased by 10% when H 2 conversion was greater than 50%.

6. The method of claim 1 wherein the flow rate of gaseous substrate is increased by 15% when H 2 conversion was greater than 65%.

7. The method of claim 1 wherein the flow rate of gaseous substrate is increased by 20% when H 2 conversion was greater than 75%.

8. A method of producing one or more alcohols from a gaseous substrate, the method comprising:

adding gaseous substrate comprising carbon monoxide (CO) and hydrogen (H 2 ) into an aqueous medium in a bioreactor, wherein the aqueous medium includes one or more anaerobic acetogenic microorganisms;

agitating the aqueous medium at an agitator speed of 10 to 1000 rpm;

measuring conversion of CO;

measuring conversion of H 2 ; and

increasing a flow rate of gaseous substrate into the bioreactor by a flow factor (proposed quantity of gaseous feed divided by current quantity of gaseous feed) of 1.05 to 2.0 when CO conversion in the bioreactor is 25 to 95%, H 2 conversion in the bioreactor is 25 to 95% and a difference between CO conversion and H 2 conversion in the bioreactor is 0% to 25%, wherein the agitator speed is increased when a second CO conversion is 0 to 25% and H 2 conversion is 0 to 25%

wherein if a concentration of acetic acid in the aqueous medium is less than about 2 grams per liter after reaching a cell density of at least 50% more than an initial cell density, then about 0.67 ml of a vitamin solution is added per liter of aqueous medium,

wherein the vitamin solution includes about 0.08 to about 1 μM biotin, about 0.12 to about 1.5 μM thiamin HCL, and about 0.15 to about 2 μM calcium d-pantothenate.

9. A method of producing, one or more alcohols from a gaseous substrate, the method comprising:

adding gaseous substrate comprising carbon monoxide (CO) and hydrogen (H 2 ) into an aqueous medium in a bioreactor, wherein the aqueous medium includes one or more anaerobic acetogenic microorganisms;

agitating the aqueous medium at an agitator speed of 10 to 1000 rpm;

measuring conversion of CO;

measuring conversion of H 2 ; and

increasing a flow rate of gaseous substrate into the bioreactor by a flow factor (proposed quantity of gaseous feed divided by current quantity of gaseous feed) of 1.05 to 2.0 when CO conversion in the bioreactor is 25 to 95%, H 2 conversion in, the bioreactor is 25 to 95% and a difference between CO conversion and H 2 conversion in the bioreactor is 0% to 25%, wherein the agitator speed is increased when a second CO conversion is 0 to 25% and H 2 conversion is 0 to 25%

wherein if a concentration of acetic acid in the aqueous medium is less than about 1.5 grams per liter after reaching a cell density of at least 50% more than an initial cell density, then about 1 ml of a vitamin solution is added per liter of aqueous medium,

wherein the vitamin solution includes about 0.08 to about 1 μM biotin, about 0.12 to about 1.5 μM thiamin HCL, and about 0.15 to about 2 μM calcium d-pantothenate.