other industries in implementing control over the process and optimization strategies. A main drawback in biotechnological process control is the problem of measuring key physical and biochemical parameters. Operational stages in a bio-process A bioprocess is composed mainly of three stages—upstream processing, bioreaction, and downstream processing—to convert raw material to finished product. The raw material can be of biological or non-biological origin. It is first converted to a more suitable form for processing. This is done in an upstream processing step which involves chemical hydrolysis, preparation of liquid medium, separation of particulate, air purification and many other preparatory operations. After the upstream processing step, the resulting feed is transferred to one or more bioreaction stages. The biochemical reactors or bioreactors form the base of the bioreaction step. This step mainly consists of three operations, namely, production of biomass, metabolite biosynthesis and biotransformation. Finally, the material produced in the bioreactor must be further processed in the downstream section to convert it into a more useful form. The downstream process mainly consists of physical separation operations which include solid liquid separation, adsorption, liquid-liquid extraction, distillation, drying etc. Specifications A typical bioreactor consists of following parts: Agitator – Used for the mixing of the contents of the reactor which keeps the cells in the perfect homogenous condition for better transport of nutrients and oxygen to the desired product(s). Baffle – Used to break the vortex formation in the vessel, which is usually highly undesirable as it changes the center of gravity of the system and consumes additional power. Sparger – In aerobic cultivation process, the purpose of the sparger is to supply adequate oxygen to the growing cells. Jacket – The jacket provides the annular area for circulation of constant temperature of water which keeps the temperature of the bioreactor at a constant value. See also ATP test Biochemical engineering Biofuel from algae Biological hydrogen production (algae) Bioprocessor Bioreactor landfill Biotechnology Cell culture Chemostat Digester Electro-biochemical reactor (EBR) Hairy root culture History of biotechnology Hollow fiber bioreactor Immobilized enzyme Industrial biotechnology Moving bed biofilm reactor Septic tank Single-use bioreactor Tissue engineering References Further reading Pauline M Doran, Bio-process Engineering Principles, Elsevier, 2nd ed., 2013 Biotechnology company External links Photo-bioreactor. Biotechnology Biological engineering Biochemical engineering