Method of operation of fermentation of gaseous substrate comprising hydrogen
View Patent ↗The present disclosure provides methods of gaseous substrate fermentation comprising: adding gaseous substrate into an aqueous medium in a bioreactor. The methods of the present disclosure comprise: measuring cell density; adjusting input of gaseous substrate to increase cell density; changing hydrogen uptake.
1. A process for increasing cell density in a microbial fermentation of a gaseous substrate, the process comprising:
(a) contacting an anaerobic acetogenic bacteria in an aqueous medium with a gaseous substrate comprising hydrogen and carbon monoxide in a bioreactor, thereby forming a fermentation medium;
(b) adjusting an amount of hydrogen provided to the fermentation medium comprising:
(i) measuring a rate of input of hydrogen into the bioreactor;
(ii) measuring a rate of output of hydrogen from the bioreactor;
(iii) determining a hydrogen uptake from the measured hydrogen input and output rates;
(iv) maintaining a hydrogen uptake in a range of about 0.001 to about 1.0 mmol/min by increasing or decreasing a rate of hydrogen input; and
(v) maintaining a molar ratio of H 2 uptake to total gas molecules input to the bioreactor in a range of about 3% to about 4.5%,
wherein the process provides a cell density in a range of about 0.5 to about 50 g/L, wherein said cell density is obtained thereby at a faster rate than by a reference process lacking the hydrogen adjusting step.
2. The process of claim 1 wherein the hydrogen uptake is maintained in a range of about 0.005 to about 0.5 mmol/min.
3. The process of claim 1 wherein the hydrogen uptake is maintained in a range of about 0.01 to about 0.1 mmol/min.
4. The process of claim 1 wherein the anaerobic acetogenic bacteria are selected from the group consisting of biologically pure microorganisms, naturally occurring microorganisms, non-naturally occurring microorganisms, non-naturally occurring microorganism produced by genetic modifications, mutants of naturally occurring microorganisms, mutants of non-naturally occurring microorganisms, recombinant microorganisms, engineered microorganisms, and artificially synthesized microorganism.