The increasing global environmental pollution, rising energy consumption, and global warming, which are important problems worldwide, have led countries to seek different solutions in environmental issues. Türkiye and other countries are making efforts to continue living in a healthier environment economically and socially while meeting the increasing energy demand and rising environmental pollution. Renewable technologies are being developed and produced. Therefore, sustainable ecology and sustainable green economy have started to take the top spot on the global agenda. For this reason, the use of microalgae in environmental applications is increasing rapidly, and microalgae technology is being rapidly developed. Photobioreactors are currently at the forefront of microalgae production. Accordingly, microalgae are being used in many different areas of biotechnological and technical applications, such as health, food, cosmetics, pharmaceutical production, wastewater treatment, heavy metal removal from the environment, and animal feed. In addition, the production of biofuels based on microalgae is also attracting attention. Therefore, microalgae are creating potential alternatives to coal, petroleum, and natural gas. In this sense, it seems inevitable that microalgae will be one of the main energy sources in the future, and a green revolution will take place with the development of microalgae technology. This study aims to reflect the current situation of algae and microalgae used and that can be used in biotechnology, along with new applications and necessary considerations in Türkiye, as well as in the world.