NOVELTY - Extending carbon chain length involves processing waste water sludge, garbage, water sediment, petroleum contaminated soil or alkaline agents, anaerobically to yield biogas. The bioreactor for stimulating extension of carbon chain length is utilized, where the bioreactor comprises an ion exchange membrane separator connected to an anode compartment and a cathode compartment. The anode compartment is connected to the cathode electrode through an external power supply by wires.    USE - Method for extending carbon chain length by electrical stimulation (claimed).    ADVANTAGE - The method enables to extend carbon chain using alcohols, ketones and other organic matters, therefore increasing the value of resources in accordance to the environment protection policy, in an efficient manner.    DETAILED DESCRIPTION - Extending carbon chain length involves processing waste water sludge, garbage, water sediment, petroleum contaminated soil or alkaline agents, anaerobically to yield biogas. The bioreactor for stimulating extension of carbon chain length is utilized, where the bioreactor comprises an ion exchange membrane separator connected to an anode compartment and a cathode compartment. The anode compartment is connected to the cathode electrode through an external power supply by wires. Electrical stimulation is carried in the bioreactor for stimulating the carbon chain extension, where the anode chamber and the cathode chamber are kept free of oxygen and the electrolytic solution is filled into the anode compartment, whereas the cathode compartment is filled with nutrient salt solution containing acetic acid and the obtained microbial inoculum i.e. waste water sludge, garbage, water sediment, petroleum contaminated soil or alkaline agents, anaerobically to yield biogas. An external power supplied by biogas generates electrons, which are transferred to the cathode electrode gradually in order to enrich the formation of microbial inoculum biofilms. The formed microbial inoculum biofilms on the surface of the cathode electrode are continuously fed onto the raw materials comprising low-carbon-chain organic acids, which are converted to long-chain organic acid/alcohol that are continuously discharged in the bioreactor. An INDEPENDENT CLAIM is included for a carbon chain length extending device, which comprises an anode room, an ion exchange film, cathode compartment that embeds cathode electrode, and anode compartment that embeds cathode electrode.