What are bioreactors? How are large volumes of cultures maintained and processed in them?

Explanation

### Step-by-Step Solution:

1. **Definition of Bioreactors**:
- Bioreactors are specialized apparatuses designed for growing organisms such as bacteria, yeast, or other cells under controlled conditions. They are commonly used in fermentation processes and biotechnology.

2. **Controlled Environment**:
- A bioreactor maintains specific conditions necessary for the growth of organisms. This includes regulating temperature, pH levels, and providing essential nutrients. These controlled environments ensure optimal growth and productivity of the cultures.

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