Bioreactor Characteristic of Baker’s Yeast Production

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Bioreactor Characteristic of Baker’s Yeast Production
1. Using Saccarahomyces cerevisiae as a seed yeast
Baker’s yeast is produced from the genus and species of yeast called Saccharomyces cerevisiae. The scientific name of the genus of baker’s yeast, Saccharomyces, refers to “saccharo” meaning sugar and “myces” meaning fungus. The species name, cerevisiae, is derived from the name Ceres, the Roman goddess of agriculture. Baker’s yeast products are made from strains of this yeast selected for their special qualities relating to the needs of the baking industry.

2. Using molasses as a medium
Molasses obtained from the beet or sugar cane extraction.

3. Submerged
Submerged in here means the seed yeast and the medium immerse on the water tank.
At the past, before the submerged bioreactor technology appears, the scientist usually use the tray bioreactor. But because this method is inefficient for producing large commercial quantities, it fell quickly to the wayside with the emergence of submerged tank systems, which are designed to handle significantly higher volumes.

4. Fed-batch fermentation process
This hybrid of batch and continuous operations is found in many types of processes. One of the more frequently used is initiating the bioreaction in the batch mode, until the growth-limiting substrate has been consumed. Then, the substrate is fed to the reactor as specified (batch) or is maintained by an extended culture period (continuous). For secondary metabolite production, in which cell growth and product formation often occur in separate phases, the substrate is typically added at a specified rate.

5. Stirred tank
The most common type of aerobic bioreactor in use today is the stirred-tank reactor, which may feature a specific internal configuration designed to provide a specific circulation pattern. Ideal for industrial applications, this unit offers manufacturers both low capital and operating costs. For laboratory experiments with smaller volumes, the mixing vessel is typically made of glass. Stainless steel tank construction is the standard for industrial applications involving larger volumes. The height-to-diameter ratio of the vessel can vary, depending on heat removal requirements.


The operating principles of the stirred-tank bioreactor are relatively simple. The sterile medium and inoculum are introduced into a sterilized tank, and the air supply typically enters at the bottom. For optimal mixing, the tank features not only an agitator system but also baffles, which help prevent a whirlpool effect that could impede proper mixing. In the early stages of the process, warm water may be circulated through the baffles to heat up the system; later, cool water may be circulated inside of them to keep the process from overheating. The number of baffles typically ranges from four to eight. As the bioreaction progresses, the bubbles produced by the air supply are broken up by the agitator as they travel upward. Many types of agitators are currently used, with the most common one being the four-bladed disk turbine. Newer designs featuring 12 or 18 blades, or concave ones, have also been shown to improve the hydrodynamics. At the top of the tank, exhaust gas is discharged and the product flows back down, where it is drained from the tank. In a continuous flow stirred-tank reactor, the substrate is continuously fed into the system and the product is continually drawn out and separated, with the producing organism recycled back into the tank for reuse. As with conventional chemical reactors, bioreactors can be placed in series or parallel with controlled recycle streams.

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