Method for producing alcohols using a support on which microorganisms are immobilised

A process for producing alcohols, characterized in that it is a process for producing a mixture of alcohols of Acetone-Butanol-Ethanol type, Isopropanol-Butanol-Ethanol type, or Isopropanol-Butanol-Ethanol-Acetone type, according to which a sugary fluid (2) is introduced into a reaction section (1) comprising a support made of porous solid material and comprising a plurality of portions or layers of loose porous solid material, which are arranged successively in a general direction of flow of said sugary fluid (2) in the reaction section (1), (4) on which microorganisms of the genus Clostridium, which microorganisms produce isopropanol naturally, are genetically modified to produce isopropanol, or both, are immobilized, in order to produce, by fermentation, an alcohol-enriched must (3) under the action of said microorganisms, characterized in that the process is carried out continuously, in that a portion of spent support (41) is periodically replaced by a portion of new support, by a portion of regenerated support, or by a portion of a combination of new support and regenerated support (46), characterized in that only a portion is replaced each time a replacement is made.