Specialized Bioreactors

Specialized BioreactorsIntroductionThe term fermentation is derived from the Latin verb fervere, to boil, which describes the appearance of the action of yeast on extracts of fruit or malted grain during the production of alcoholic beverages.

Definitions of fermentationFermentation is the chemical transformation of organic substances into simpler compounds by the action of enzymes, which are produced by microorganisms such as molds, yeasts, or bacteria. According to BiochemistFermentation is an anaerobic process where energy is produced without the participation of oxygen or other inorganic electron acceptors. (life without air) According to Microbiologist Any process for the production of a product by the mass culture of microorganisms. History of fermentation Ethanol fermentation was one of the first chemical reactions observed by humans. Pioneers in microbiologyAnthony Van Leeuwenhoek[1632-1723]

Made the earliest microscopes which magnified up to 300X.Discovered micro-organisms.

Louis Pasteur(1822-1895)Showed microbes caused fermentation & spoilageDisproved spontaneous generation of microorganismsDeveloped aseptic techniquesRobert KochDeveloped pure culture methods.Established a sequence of experimental steps to show that a specific m.o. causes a particular diseaseKochs Postulates

What are bioreactorsBioreactor is a vessel in which a chemical process is carried out which involves organisms (mainly microbes-viruses or bacteria, fungi and yeasts traditionally designated as Fermenters) or biochemically active substances (enzymes, e.g.) derived from such organisms in opposite to fermenters frequently considered as true bioreactors. This process can either be aerobic or anaerobic. ORAn apparatus, such as a large fermentation chamber, for growing organisms such as bacteria or yeast that are used in the biotechnological production of substances such as pharmaceuticals, antibodies, or vaccines, or for the bioconversion of organic waste. ORA bioreactor may also refer to a device or system meant to grow cells or tissues in the context of cell culture. Cell culture is the process by which cells are grown under cultivated conditions (animal cells, plant cells, algae).

The bioreactors environmental condition like gas (oxygen, nitrogen, carbon dioxide) and liquid flow rates, temperature, pH, concentration of substrate and products, cells number and their composition (proteins and nucleic acids), dissolved oxygen levels,, and agitation speed (or circulation rate) need to be closely and continuously monitored and controlled. In many cases, strictly aseptic conditions have to be maintained.

Classification On the basis of mode of operation batch bioreactorfed batch bioreactorcontinuous bioreactorOn the basis of mode of flow of fluids CSTR bioreactor (continuous flow stirred reactor-the content of the bioreactor is ideally mixed) bioreactor with piston flow bioreactors with non- ideal flow of fluids On the basis of a number of phases treated homogeneous bioreactors heterogeneous bioreactors

Airlift bioreactorsThe term airlift reactor (ALR) covers a wide range of gasliquid or gasliquidsolid pneumatic contacting devices that are characterized by fluid circulation in a defined cyclic pattern through channels built specifically for this purpose.The main difference between ALRs and bubble columns (which are also pneumatically agitated) lies in the type of fluid flow, which depends on the geometry of the system.Parts of airlift bioreactorRiser. The gas is injected at the bottom of this section, and the flow of gas and liquid is predominantly upward.Downcomer. which is parallel to the riser, is connected to the riser at the bottom and at the topBase. The base does not significantly affect the overall behavior of the reactor, but the design of this section can influence gas holdup, liquid velocity, and solid phase flowGas separator This section at the top of the reactor connects the riser to the downcomer, facilitating liquid recirculation and gas disengagementAirlift Bioreactor morphologyAirlift reactors can be divided into two main types of reactors on the basis of their structureExternalloop vesselsbaffled (or internal-loop) vesselsExternal loop airlift BioreactorExtrernal loop airlift bioreactor has a air sparged riser column physically separated from the downcomer.

Internal loop airlift bioreactor

ApplicationsAirlift bioreactors are usedin Mammalian cel clutureWaste water treatmentsTo produce biopharma proteins from fragile cells.AdvantagesIdeal for shear sensitive mammalian and olant cell cultures.No mechanical agitation, thus low power consumption and good aseptic environment High oxygen transfer rates.DisadvantagesGreater throughput and higher pressure is needed no bubble breakerInefficient break of foam when foaming occurs.Photo bioreactorThe prefix PHOTO particularly dscribes the bioreator property to cultivate phototropic micro organisms or organisms which grow on by utilizing light energy.These organisms use the processs of photosynthesis to buils their own biomass from light and CO2.Micro-algae are source of unique metabolites that can be used to produce novel high-added value bioactive compounds with industrial potential in medical technologies or as food, feed or cosmetic ingredients or as potential source of biofuels.

Types Open pond photo bioreactorsThe open pond photobioreactor is simply an open body of water exposed to the environmental elements.First aporach of open pond photobioreactro is the controlled production of phototropic organisms by susoension culture methods.To maximize the amount of algae growth the open pond photobioreactors re installed with agitators to expose more lgae to sunlight.Closed system photobioreactor Consist of a clear container with co2 bubbling through water containing algae.Provided with a artificial light illuminated 24 hours a day. This is another advantage over the open pond photobioreactor. types of closed system photobioreactor Tubular photobioreactorPlate type photobioreactorTubular photobioreactorTubular photobioreactors are made up of glass or plastic tubes oriented horizontally or vertically.Tpbr helps in production of healthy growth of algal culture with very low risk of contamination compared to open ponds.E.g., production of carotenoid Astraxanthine from the green algae Haematococcus pluvialisDifferent forms of tubular photo bioreactors

Plate type photobioreactor[PTBR]These are constructed using plastic or glass platesThe plates with different technical designs are mounted to form a small layer of culture suspension, which provide optimised light supply.

Working of photo bioreactorInitially water, algal culture, co2, nutrients and other growth necessities are fed into a feeding vessel.From feeding vessel the flow progress to the diaphragm pump which moderates the flow of the algae into the actual tube.co2 intake valve is also provided to facilitates photosynthesis. the bioreactors are designed to have light and dark intervals to enhance growth rate of algae.Once the algae are ready to harvest, they are pass through the filtering system, which filters the algae that are ready for processing. while remaining algae passes back to the feeding vessel, then flow continues.

Advantages Cultivation of algae is in controlled circumstances, hence potential for much higher productivity.Space saving can be mounted vertically or horizontally and indoor or outdoor.Permits the production of complex biopharma ceuticals.DisadvantagesThe technical difficulty in sterilizing these photo bioreactorsCapital lose is very high Tubular bioreactorTubular bioreactors havesimple construcstion and possibility to prepare diffenrent inner configurations by the use of standard industrial support materials like pipes,pumps, standard settings etc.Mixing in tubular bioreactors aremore uniform campared to stirred tank bioreactorTubular systems are especially useful for production of specialized chemicals.Agitation may bemade possible by introducing impellers connected to a common motor- driven shaft.

AdvantagesUsually have simple construction.Two microbes can be cultivated by creating two compartments using semipermeable membrane.suitable for continueous mode of operation.DisadvantagesIt has realatively low oxygen supply capacity,which makes it unsuitable for construction of bioprocess with high oxygen demand.Membrane bioreactor

membrane bioreactor is the combination of a membarene process like microfiltration or ultrafiltaration with a suspended growth bioreactor.Usually used in conjugation with various other separation process such as Revers osmosis and ultrafiltration to provide a product stream which is free of undesired contaminants.The membarne used is either organic polymer or cerramic materils with pore size 0.0003-0.01mMembrane bioreactor configurations1> internal/submerged membrane bioreactorThe membareane areaimmersed in and are integral to the bioractor.It is installed in either main bioractor vessel or in separate tank.External or side stream membrane bioreactorThe membrane re a separate unit process reqiring an intermediate pumping stepThe filtration elements are installed externally to the reactor.The biomass is pumped directly thorough a number of membrane modules in series and back to the bioreactor Advantages the advantages of using membrane bioreactor system over other conventional systems areBetter effluent quality.Smaller space requirementEase of automation.DisadvantagesTypically higher capital and operating costHigh energy consumption.