The exploration of new energy resources has been a major challenge in the last decades for urban development. Biohydrogen is one of the most efficient renewable sources because the consumption of fossil fuels is highly polluting the environment. The production of biohydrogen from microalgae is a very attractive approach that helps to achieve bioenergy sustainability and carbon neutrality. However, the low yield of biohydrogen production appears to be the main challenge with microalgae. The aim of this research was to study the production of biohydrogen by Scenedesmus obliquus and various pretreatment methods such as physical, chemical and biological to increase the yield. The chemical pre-treatment process such as the alkaline method produces more hydrogen than other methods.