Which of the following sensor penetrates into the fermenter?*a) Exhaust-gas analyzersb) pH electrodesc) Tachometersd) Load cells

The sensor that penetrates into the fermenter from the options given is:

b) pH electrodes

Explanation:

pH electrodes are designed to be immersed in the liquid within the fermenter to measure the acidity or alkalinity of the fermentation medium. This is crucial for monitoring the fermentation process, as the pH can significantly affect microbial activity and fermentation efficiency.

In contrast:

• Exhaust-gas analyzers typically measure gases emitted from the fermenter without penetrating it.
• Tachometers measure the speed of rotating equipment (like mixers or agitators) but do not penetrate into the fermenter.
• Load cells are used for weighing and measuring the weight of the fermenter or contents but do not physically enter the tank.

Thus, among the options provided, pH electrodes are the ones that penetrate into the fermenter itself.