Anaerobic digestion is an effective biotechnological process for treatment of different organic waste with production of biogas. In this paper the performed mathematical analysis of the behavior of a bacterial consortium during biomethane synthesis is presented. A new pathway of biomethane production was studied based on the metabolism of hydrogenotrophic bacteria where up to 30% of biometane can be synthesized. The other group involved in biomethane synthesis were recognised as acidoclastic methanogenes and based on their metabolic activity up to 70% of biometane produced can be achieved. The model analysis was focused on balance equations of biomethane production where microbial kinetics in the liquid phase was focused on the above mentioned metabolic pathways, and how microbial consortia responded to the high organic loads and changes of dilution rate. The simulation results with the model have shown very interesting findings when high organic loads were applied and can be used for off line process optimization.