The design and functionality of bioreactors are a meticulous blend of engineering and biological principles. The primary goal is to create an artificial ecosystem that closely mimics the natural conditions required for the thriving of the cultured entities. The structure of a bioreactor typically consists of a vessel made of materials that are chemically inert, resistant to corrosion, and capable of withstanding sterilization processes to maintain asepsis.

The interior of the bioreactor is equipped with various components that play crucial roles in supporting cell and microbial growth. Agitation systems, such as impellers or magnetic stirrers, ensure uniform mixing of the culture medium, preventing the formation of gradients in nutrient distribution, oxygen availability, and pH. This homogeneity is essential for the consistent development and performance of the cells or microorganisms throughout the tank.

Temperature control is another critical aspect. Microorganismos Bioreactors are often fitted with jackets or coils through which heated or cooled fluids are circulated to maintain a precise and stable temperature. Different cell types and microbial species have specific temperature optima for optimal growth and metabolic activities, and even slight deviations can have significant impacts on their productivity and viability.

Oxygen supply is of paramount importance, especially for aerobic cultures. Aeration systems, including spargers or membrane oxygenators, are incorporated to introduce oxygen into the medium. The rate of oxygen transfer is carefully regulated to meet the respiratory demands of the cells or microorganisms without causing excessive foaming or oxidative stress.

pH regulation is achieved by the addition of acids or bases as needed, and pH sensors monitor the medium in real-time to ensure that the pH remains within the narrow range suitable for the culture. The control of these parameters collectively creates an environment that promotes the healthy growth and efficient functioning of the cells or microorganisms.

The type of bioreactor chosen depends on several factors, including the scale of the operation, the nature of the cells or microorganisms being cultured, and the specific requirements of the process. Batch bioreactors are commonly used for small-scale experiments and processes where a fixed volume of culture is processed in one cycle. 

Continuous bioreactors, on the other hand, offer a continuous inflow of fresh medium and outflow of spent culture, providing a more steady-state operation and potentially higher productivity over time.

The application of bioreactors in cell and microbial culture is incredibly diverse. In the field of medicine, they are employed for the production of therapeutic proteins, antibodies, and vaccines. Engineered mammalian cells or microbial hosts are cultivated in bioreactors to generate these vital biomolecules in large quantities with the desired quality and purity.

In the food industry, bioreactors are utilized for the production of enzymes, flavors, and food additives. Microbial cultures in biofermentation tanks can transform raw materials into valuable products that enhance the taste, texture, and shelf life of various food items.

Environmental biotechnology also benefits from bioreactors. They can be used for the degradation of pollutants, the treatment of wastewater, and the production of biofuels from microbial metabolism. The ability to manipulate and control the growth conditions of microorganisms in bioreactors offers potential solutions for addressing some of the most pressing environmental challenges.

The use of bioreactors for cell and microbial culture is not without its challenges. Maintaining sterility throughout the process is of utmost importance to prevent contamination, which can lead to the failure of the entire culture. Monitoring and controlling the complex interplay of multiple parameters in real-time requires sophisticated sensor technologies and control systems. 

Scaling up from laboratory-scale bioreactors to industrial-sized tanks often poses difficulties related to maintaining homogeneity, heat and mass transfer, and process economics.

Advancements in technology are constantly addressing these challenges and driving the evolution of bioreactor systems. The integration of artificial intelligence and machine learning algorithms enables more precise prediction and optimization of process parameters. 

The development of novel materials and surface coatings enhances biocompatibility and reduces fouling. Miniaturization and microfluidic-based bioreactors offer new possibilities for high-throughput screening and point-of-care applications.

In conclusion, bioreactors stand as the indispensable workhorses of cell and microbial culture within biofermentation tanks. Their continuous improvement and innovation are crucial for advancing various industries, from healthcare and food production to environmental sustainability. The understanding and mastery of bioreactor technology will undoubtedly continue to shape the future of biotechnology, opening up new frontiers in the production of valuable products and the solution of global challenges.