NOVELTY - Converting feed gas containing CO, H2 and/or CO2 to liquid product involves: passing feed gas into vessel that retains fermentation broth and microorganisms under anaerobic conditions with broth supplying nutrients to microorganisms that produce liquid product; passing into injector; delivering entrained feed gas and liquid medium to fermentation broth as plume and injecting plume into the vessel; retaining inert microorganism carriers having a surface supporting biofilm of microorganisms in vessel; passing plume upward and horizontally through vessel; and withdrawing and recovering.    USE - For converting a feed gas containing at least one of CO, H2 and CO2 and a mixture of CO2, H2 and CO to a liquid product (claimed) used as biofuel such as liquid motor fuel.    ADVANTAGE - The combining of moving bed biofilm reactor (MBBR) process for gaseous components of CO and/or CO2/H2 with a highly efficient gas transfer process results in economical and high product volumetric production rate process for producing liquid fuels such as ethanol. The method retains the microorganisms in the form of biofilm; uses buoyant or suspended carrier as a media for supporting the biomass; and uses device that promotes high gas dissolution and utilization.    DETAILED DESCRIPTION - A process for converting a feed gas containing at least one of CO, H2 and CO2 and a mixture of CO2, H2 and CO to a liquid product, involves: a) passing a feed gas into a vessel that retains a fermentation broth and microorganisms in it under anaerobic conditions with the fermentation broth supplying nutrients to the microorganisms that produce a liquid product from the feed gas; b) passing the feed gas and liquid medium into an injector to at least partially entrain the feed gas into the liquid medium as microbubbles; c) delivering the entrained feed gas and liquid medium to the fermentation broth as a plume and injecting the plume into the vessel in horizontal direction; d) retaining inert microorganism carriers having a surface supporting a biofilm of the microorganisms in the vessel that are arranged for circulation throughout the fermentation broth in the vessel; e) circulating the biomass carriers containing the microorganism and the broth in the vessel so that a portion of the carrier and the broth from time to time directly and immediately contact the plume of feed gas and liquid medium at the location, where the feed gas and liquid medium enter the vessel in the horizontal direction; f) passing the plume upward and horizontally through the vessel after the horizontal injection of the liquid medium and feed gas through the feed injector so that at least a part of the plume travels in a horizontal direction at least half way across the vessel so that broth and microorganism receive feed gas across the full cross section of the vessel; and g) withdrawing fermentation broth containing liquid products from the vessel through a carrier retainer to impede the withdrawal of the carrier material with the broth; and h) recovering liquid product from the withdrawn broth.