Bioreactors: Bioreactors can refers to any device or machine that are biologically active and can grow cell, tissue in optimised. Conditions where the large volume upto (100 - 1000) litres can cultured. When the raw material have to be added and it performs bioprocess engineering. Processing done with biological agents such as cells, enzymes and antibodies, with the optimum growth conditions such as temperature, pH, nutrients concentration, oxygen level are also required at last we get products at large scale, which can also withdraw in small amount time to time.

Down streaming Process:  This is the final stage where the biotransformants or biosynthesised products has to be pour out and converted into more useful form. This include the separation aryl purification of product like liquid - liquid extraction, distillation, drying and must be added preservatives. If the product has to be go for the drugs formation. Then it has to face many clinical trials for its validity. After many kinds of testing finally our product is ready for marketing. Most commonly used bioreactors are stirring type. They are biological active and have 100 to 1000 leters of volume at a time.

Continuous Culture System: The continuous culture system carry material as a flowing stream. Bioreactors can produce large amount of product continuously because they are designed like that where the used medium is drained out from one side while the fresh raw materials can be added continuously from the another side so we get larger biomass leading high yield of product.