▎ 摘　　要

NOVELTY - Fermentation system comprises dark-light combined hydrogen production device (1), hydrogen quality detection system (2), hydrogen purification device (3), gas collecting tank (4), ultra-micro bubble nano-device (5), methane production device (6) and methane purification device (7). The dark-light combined hydrogen production device is an integrated reactor, which is provided with a dark fermentation hydrogen production unit and a photosynthetic fermentation hydrogen production unit. The dark-light combined hydrogen production device is connected with the hydrogen quality detection system through a metal hose. The hydrogen quality detection system is connected to the hydrogen purification device through a metal hose. The hydrogen quality detection system and the hydrogen purification device are connected by metal hoses. USE - The fermentation system is useful for co-production of biohydrogen alkane. ADVANTAGE - The fermentation system has negative carbon emission, reduces cost of hydrogen purification, increases amount of methane produced and recycles carbon dioxide captured in purification process of high-quality hydrogen and methane. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for fermentation method for co-production of biohydrogen alkane, involves (a) taking mixed bacteria comprising dark fermentation hydrogen-producing bacteria and photosynthetic hydrogen-producing bacteria, and fermentation substrate i.e. enzymatic hydrolyzate of crop straw, (b) allowing the hydrogen quality detection system to send feedback information to the control system, where the control system turns on the gas flow pump in the direction of the hydrogen purification device, passes the gas into the hydrogen purification device through a metal hose for purification, detection and shunting, the separated pure hydrogen flows to the gas collecting tank through the metal hose under the action of the gas flow pump, and passing the separated carbon dioxide into the methane production device through the metal hose under the action of the gas pump and (c) setting the fermentation temperature of the methane production device at 35degrees Celsius, inoculating 20 volume/volume% methanogenic bacteria, allowing the gas generated from the methane production device to flow into the methane purification device through the metal hose pipeline under the action of the gas flow pump, where the purified methane enters the gas tank through the metal hose under the action of the gas flow pump, and returning the separated carbon dioxide to the methane production device through the metal hose under the action of the gas flow pump. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a fermentation system. Dark-light combined hydrogen production device (1) Hydrogen quality detection system (2) Hydrogen purification device (3) Gas collecting tank (4) Methane production device (6) Methane purification device (7)