Integrated processes are disclosed for the anaerobic bioconversion of syngas to alcohol wherein a gas substrate of carbon monoxide, hydrogen and carbon dioxide is in contact with an aqueous menstruum that continuously contacts the gas substrate with said aqueous menstruum to produce alcohol and a depleted gas phase that is continuously withdrawn from the aqueous menstruum; continuously or intermittently and the gas substrate is made up of at least two gases having different compositions to provide an overall gas substrate having a ratio of electrons to carbon atoms in the range of about 5.2:1 to 6.8:1.