Chapter 20: Monera, Bacteria

A Bioreactor is a vessel in which biological reactions take place.

Biological reactions that are anaerobic (no oxygen present)

• Sterile - no microorganisms present.
• Correct pH and temperature.

• Batch food processing
• Continuous flow food processing

• Fixed amount of sterile nutrient is added to the microorganisms in the bioreactor
• Bacteria go through typical stages of growth curve (lag,log….)
• (Reaction may be stopped before death stage as very little product will be formed there)

In batch food processing a fixed amount of sterile nutrient is added to microorganisms in bioreactor.

• The bioreactor is cleared out, product is separated from rest of solution and is purified.
• Bioreactor is cleaned and re-sterilised.
• Process can be repeated.

• Nutrients are continuously fed into the bioreactor and culture medium (toxins) is withdrawn.
• Microorganisms ate maintained in the log phase of growth and process can continue uninterrupted for weeks, months.
• Continuous flow bioreactors factors are constantly monitored to maintain growth in log phase (to produce maximum yield).

Nutrients are continuously fed into the bioreactor.

The culture medium ( toxins) is continually withdrawn.

Factors such as temperature, pH, rate of stirring, concentration of nutrients,oxygen and waste products are constantly monitored in order to maintain growth in log phase, producing max yield.

• Nutrients are constantly fed into bioreactor
• Culture medium (toxins) are withdrawn
• Bioreactor factors (eg temp, pH) are constantly monitored.

• Lag phase
• Log phase

Toxins