Processes for the bioconversion of syngas to oxygenated organic compound are disclosed that reliably, cost-effectively and efficiently supply sulfur nutrient to microorganisms contained in acidic, aqueous fermentation menstrua. In the processes of this invention, basic, aqueous solution used to maintain the pH of the aqueous fermentation menstruum is used to remove hydrogen sulfide from the off-gas from the fermentation menstruum for recycle to the fermentation menstruum.