A modern precision fermentation bioreactor is used to culture genetically engineered yeast (Saccharomyces cerevisiae) to produce animal-free whey protein for dairy alternatives.
Explain why the temperature inside the bioreactor must be kept tightly regulated around the yeast's optimum growth temperature of 30∘C30^\circ\text{C}30∘C.
Identify two distinct design features of the bioreactor system that are used to monitor and regulate the temperature of the culture.
A motorized impeller continuously agitates the liquid medium inside the bioreactor. Suggest two reasons why this continuous mixing is essential to achieve a high yield of the whey protein.
Before the sterile growth medium is added and the yeast culture is introduced, the bioreactor is subjected to a Clean-in-Place (CIP) cycle using high-pressure steam at 121∘C121^\circ\text{C}121∘C. Explain the biological importance of this steam sterilisation process before inoculation.
74 exam-style questions on Edexcel IGCSE Biology Food production. Each one has a worked solution and a mark scheme showing where the marks go.