Fermentation conditions optimization of producing bacteriorhodopsin by Halobacterium salinarium in a 5 L fermentor

The technological conditions for bacteriorhodopsin and biomass by the Halobacterium salinarium in a 5 L fermenter were optimized, in order to provide the basis for further application of the strain.The effects of temperature, p H, agitation speed, ventilation volume and corn pulp with different flow rates on the Halobacterium salinarium were investigated by single factor experiments.The optimum fermentation conditions were temperature at 37 ℃, agitation speed at 250 r/min, ventilation volume at 1.3 vvm, flow rate of corn pulp at 0.2 m L/min. p H was not regulated by acid and alkali in the fermentation process. Under these conditions, the maximum biomass was 4.531, the maximum BR yield was 90.86 mg/L, which was about respectively43.8% 、36% greater than those obtained with initial fermentation conditions.