NOVELTY - The method comprises conversion (2) of a portion of a methane feedstock to a substrate comprising carbon monoxide and hydrogen, anaerobically fermenting a portion of the substrate in a bioreactor containing a culture of microorganisms to produce products, passing (5) a portion of the substrate to a methanol synthesis vessel, reacting the substrate in the methanol synthesis vessel to produce methanol, passing (4) hydrogen rich gas stream to a second bioreactor containing a culture or microorganisms, and anaerobically fermenting (6) a portion of hydrogen rich gas stream to produce products.    USE - The method is useful for producing products such as ethanol, 2,3-butanediol and acetic acid from a gas stream produced in a methanol production process (claimed), where the products include acetate, propanol and butanol.    ADVANTAGE - The method ensures easy, rapid and economical production of products with high yield, improved efficiency, reduced fuel and energy consumption and increased poison resistance and without pollutants.    DETAILED DESCRIPTION - The method comprises conversion (2) of a portion of a methane feedstock to a substrate comprising carbon monoxide and hydrogen, anaerobically fermenting a portion of the substrate in a bioreactor containing a culture of microorganisms to produce products, passing (5) a portion of the substrate to a methanol synthesis vessel, reacting the substrate in the methanol synthesis vessel to produce methanol, passing (4) hydrogen rich gas stream to a second bioreactor containing a culture or microorganisms, and anaerobically fermenting (6) a portion of the hydrogen rich gas stream to produce products. The methane feedstock is converted to a substrate stream by a catalytic oxidation process. The substrate is passed into the methanol synthesis vessel before the substrate is passed into the bioreactor for use as a fermentation substrate. A first portion of the substrate passed into the methanol synthesis vessel is converted to methanol. A second portion of the substrate is passed to the bioreactor. The hydrogen rich gas stream is produced as a by-product of the fermentation, and comprises hydrogen and carbon dioxide. INDEPENDENT CLAIMS are included for:    (1) a system for producing products by microbial fermentation;    (2) method for producing alcohols; and    (3) a system for the production of alcohols.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a method for producing products.    Conversion of a portion of a methane feedstock to a substrate comprising carbon monoxide and hydrogen (2)    Passing hydrogen rich gas stream to a second bioreactor containing a culture or microorganisms (4)    Passing a portion of the substrate to a methanol synthesis vessel (5)    Anaerobically fermenting a portion of the hydrogen rich gas stream to produce products. (6)