Method for producing biomass using hydrogen-oxidizing bacteria

A continuous method for producing a biomass comprising at least 65% protein of total biomass by dry weight from hydrogen-oxidizing microorganisms comprising bacteria selected from the genus Cupriavidus sp, using one or more input streams comprising one or more gaseous substrates, comprising hydrogen and oxygen, the method comprising:

• contacting the microorganisms in a liquid phase with a nutrient composition comprising nitrogen and phosphorous-comprising compounds and the gaseous substrates, wherein the one or more gaseous substrates comprises carbon dioxide, or wherein the nutrient composition comprises carbon-comprising compounds, and wherein the input stream and nutrient composition are controlled and wherein the biomass is produced at a rate of more than 10 g/l/d, the method further comprising:
• i. controlling the input stream comprising adding a molar ratio of hydrogen:
• oxygen to the liquid phase of from 1:1 to 10:1;
• ii. controlling the input stream and nutrient composition comprising maintaining a specific growth rate of the microorganisms of from 1.0 to 8.0 d−1 or from 0.04 to 0.3 h−1;
• iii. controlling the input stream comprising maintaining hydrogen at a transfer rate of from 0.03 to 1.2 mol/l/h in the liquid phase or oxygen at a transfer rate of from 0.003 to 0.4 mol/l/h in the liquid phase;
• and
• iv. replacing the liquid phase of the bioreactor where the microorganisms are grown and maintained at a volume of from 4 to 30% per hour;
• wherein a microbial concentration of at least 10 g/l is maintained in the liquid phase.