System and process for increasing protein product yield from bacterial cells

A system for increasing a recovery rate of a protein-containing product purified from anaerobic bacteria cells, comprising:

• a fermentation vessel connected to a gas inlet line for flowing a gaseous substrate into the fermentation vessel containing the anaerobic bacteria cells to ferment the gaseous substrate by the anaerobic bacteria cells into a fermentation liquid broth at a first pH value;
• a first cell separator connected to one or more first outlet lines of the fermentation vessel to receive a first flow of the fermentation liquid broth from the fermentation vessel and separate the first flow of the fermentation liquid broth into a first cell-containing suspension and a first cell free permeate;
• a second cell separator connected to one or more second outlet lines of the fermentation vessel to receive a second flow of the fermentation liquid broth from the fermentation vessel and separate the second flow of the fermentation liquid broth into a second cell-containing suspension and a second cell free permeate;
• a processing chamber connected to the second cell separator to receive the second cell free permeate and process the second cell free permeate into an oxygenated hydrocarbonaceous compound;
• one or more rupturing devices connected to one or more first outlets of the first cell separator to rupture cell membranes of the anaerobic bacteria cells contained within the first cell-containing suspension into a homogenate at a second pH value, wherein the second pH value is higher than the first pH value;
• and
• one or more fractionators connected to the one or more rupturing devices to receive the homogenate from the one or more rupturing devices and fractionate the homogenate into one or more protein-containing portions having the protein-containing product and one or more protein-containing cell debris portions.