The sharp increase in energy consumption in the world and the production of waste are important environmental challenges. Microbial anaerobic digestion of waste along with methane and fertilizer production is an economical and environmentally friendly method. Codigestion of suitable substrates with the right mixing ratio removes barriers of digestion alone. The aim of this study was to investigate the effect of codigestion of sugarcane with algae in the Caspian Sea on biogas production. To measure the production of biogas in the digester, different treatments including sugarcane, algae and their mixtures were prepared in two ways: untreated and treated with one molar sodium hydroxide. In each anaerobic digester, a volume of 20 ml of inoculum (cow manure) and two grams of substrate were added and the final volume of digestion was increased to 80 ml with water . The digestion bioreactor was incubated for 37 days at 37 ° C. The volume of biogas produced in the digestion was measured at 5-day intervals. The results of biogas production showed that the highest volume of daily gas production in the digester containing untreated sugarcane in the first 5 days was 22.57% (v / v). Also, the lowest amount of recent digester was produced in the last 5 days at a daily value (v / v) of 0.2%. The amount of biogas production in the digester containing sugarcane treated with 1 M sodium hydroxide was appropriate so that from the twenty-first to the twenty-fifth day with the amount of gas produced daily was 4.765%(v / v). Also, the results of biogas production in sugarcane with algae codigestion were 3.184% (v / v) on average daily, which compared to the average daily gas production during the 30-day period, more than both digesters containing untreated and treated sugarcane. The results of the present study showed that the codigestion of sugarcane with algae increases the production of biogas. Also, alkaline pretreatment increased and continued gas production. Increasing the efficien
