NOVELTY - The production of methane from highly-organic substrates in dissolved and solid form, comprises generating gas needed for the driving power of agitators (57) in reactors (2), and condensing and supplying the gas to the medium of the fermenting substrate that promotes microbiological decomposition and transformation process. The condensed gas from the reactors is supplied to gas conducting systems (36). Containers are provided with a drain and an inlet. The driving power of the agitators takes place by utilization of the buoyancy forces of gas-collecting troughs (3).    USE - For producing methane from highly-organic substrates in dissolved and solid form (claimed).    ADVANTAGE - The procedure uses buoyancy forces of gas-collecting troughs for the production of methane without having external agitators, thus ensuring equipment cost- and energy saving procedure.    DETAILED DESCRIPTION - The production of methane from highly-organic substrates in dissolved and solid form, comprises generating gas needed for the driving power of agitators (57) in reactors (2), and condensing and supplying the gas to the medium of the fermenting substrate that promotes microbiological decomposition and transformation process. The condensed gas from the reactors is supplied to gas conducting systems (36). Containers are provided with a drain and an inlet. The driving power of the agitators takes place by utilization of the buoyancy forces of gas-collecting troughs (3) that are filled with the biogas produced in the reactors. The reactors are equipped with partition walls (31) with conducting channels (32), transporting channels (33) and gas overflow mechanisms (30). The reactors are designed with agitators and are equipped mutually with gas pipelines, and include cutoffs for the gas transport and pipelines with cutoffs for the transport of the substrate to be fermented. The gas collecting troughs are designed by means of special shaping as mixing and agitating tools and are led on a common shaft by means of spacers and are designed with respect to their shape and number in such a manner that the gas blown in by means of gas injection points and flows in every position of the agitator into the gas collecting troughs. The gas needed for the operation of the agitator is obtained from reactors, which are operated in a parallel manner or sequentially one after the other and then led into the gas collecting troughs through one or more gas injection points that are arranged at different elevations, according to the specified pressure conditions. The rotational speed of the gas collecting troughs is controlled by means of the regulation of the quantity of the gas supply by means of the pressure control and drain mechanisms. The excess substrate to be fermented is provided with two or more drainpipes at different elevations by means of a drain mechanism. The uppermost drain pipe limits the maximum filling level without a cutoff and the lower-lying drain pipe that is exposed to the atmosphere limits the minimum filling level and the lower-lying drain outlets are equipped with cutoffs. The gas supply required for the operation of the agitators takes place by means of the bearing shaft or a compression station and is fed to the gas collecting troughs by means of further gas transporting mechanisms.    DESCRIPTION OF DRAWING(S) - The diagram shows gas reactors.    Reactors (2)    Gas-collecting troughs (3)    Gas overflow mechanisms (30)    Partition walls (31)    Conducting channels (32)    Transporting channels (33)    Gas conducting systems (57) Agitators. (36)