International Journal of Science and Society, Volume 4, Issue 3, 2022 IJSOC © 2022 http://ijsoc.goacademica.com 26 Hydrogen Production by Algae Scenedesmus sp. Biomass through Photosynthesis Process Kiki Rezki Lestari 1 , Fitria Hidayanti 2 , Ucuk Darusalam 3 1,2,3 Department of Engineering Physics, Faculty of Engineering and Science, Universitas Nasional Jakarta, Indonesia Email: kiki.rezki@civitas.unas.ac.id Abstract The hydrogen production was studied using Scenedesmus sp. by PHM-S media under anaerobic and photosynthesis process. The Investigated of hydrogen gas using by Natural Gas Analyzer (NGA): HP (Hewlett Packard) 6890 with a molecular sieve 5A (CH4, O2. N2, H2) a thermal conductivity detector is used in a mesh-packed column. The results show highest value of hydrogen production in second experiment. It was obtained because the second experiment had longer for incubation time so the photosynthesis process was took longer then algae could produce more hydrogen gas. Interestingly, the hydrogen does not produce within a certain timeframe. We believe that this was related to the reaction enzymatic in algae that was mostly induced by the oxygen, an inhibitor of the hydrogenate enzyme, was reduced during anaerobic adaptation, resulting in an increase in hydrogen production. Keywords: Biomass; Scenedesmus sp.; Anaerobic Incubation; Photobioreactor; Hydrogen Production. ——————————  —————————— A. INTRODUCTION The primary source of energy consumed worldwide remains conventional fossil fuels including coal, oil, and natural gas (Liu et al., 2012). Nevertheless that these conventional fuels are nonrenewable, with diminishing reserves and rising costs, is well known (Cai & Wang, 2013; Lei et al., 2012). Solar energy, hydropower, wind energy, geothermal energy, biomass energy, and ocean energy are among the currently identified renewable energy sources. The search for new fuel sources to replace fossil hydrocarbons has accelerated. Hydrogen is regarded as an ideal, non- polluting fuel for the future (Gest & Kamen, 1949). Biomass is one of the promising renewable and neutral consider the carbon dioxide emissions. Biomass is the organic materials produced by reaction between carbon dioxide, water, sunlight, and other nutrients through photosynthesis (Sugie et al., 1984). There are several sources of biomass energy are being developed in several countries. The use of algae (microalgae) as a raw material has a bright prospect for microalgae easily cultivated and can produce more than other raw materials. The production of biofuel from algae has received the most attention in recent years compared to other potential products. The conversion of plant storage carbohydrates (sugars and starch) into fuel was the foundation of the first generation of biofuel production (Manwell et al., 2010). The production of biofuels is one of the steps taken to increase access and reduce reliance on fossil fuels, particularly since