<p>Bioreactors are known for their ability to provide a controlled environment for the cultivation of various biological systems. While microbial systems are primarily known for their speed and cost advantages in industrial enzyme and simple protein production, mammalian cell systems continue to be the platform for clinical therapies due to their complex glycosylation requirements and viral vector production. Moreover, plant cell-based systems offer a new production paradigm focused on biosafety and sustainability. The main challenge with traditional bioreactors is the shear stress that occurs when trying to deliver equal oxygen and nutrients to every cell in large-scale production, damaging the delicate cells. Another challenge is the uncontrolled microenvironments that lead to deviations in product quality. As in other fields, with the changing application and engineering approaches, the diversification and development of bioreactor systems continues unabated. Looking to the future, it is predicted that the transformation in bioreactor technologies, driven by digitalization, artificial intelligence, and customized bioreactor mechanisms, will close the gaps in traditional approaches. This review aims to provide a comprehensive and up-to-date overview of bioreactor technologies with a particular focus on their biological diversity, engineering design, and functional principles by systematically examining microbial, mammalian, and plant bioreactor systems.</p>