Section 4: Bioprocess Engineering and Process Biotechnology
Bioreactor types, scale-up
Subtopic: Fundamentals of Bioreactor types, scale-up
Question Statement:
oxygen tension was found to be 80% air saturation under steady state conditions. The measured
Oxygen transfer was measured in a stirred tank bioreactor using dynamic method. The dissolved
oxygen tensions at 7 s and 17 s were 55% and 68% air saturation, respectively. The volumetric
mass transfer coefficient KLa is _
Q.065 to 0.078
Official Answer Key:
0.065 to 0.078
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2015 Q.44)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **NAT** (2 Marks)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Mathematical & Quantitative Formulation**:
- Problem Statement: *"oxygen tension was found to be 80% air saturation under steady state conditions. The measured
Oxygen transfer was measured in a stirred tank bioreactor using dynamic method. The dissolved
oxygen tensions at 7 s and 17 s ..."*
- Identifying governing bioprocess / mathematical relation:
- Evaluating volumetric mass transfer rate for oxygen in aerobic fermentation:
$\text{OTR} = k_L a (C^* - C_L)$
where $k_L a$ is volumetric mass transfer coefficient, $C^*$ is equilibrium saturation dissolved oxygen concentration, and $C_L$ is actual bulk liquid concentration.
- **Calculated Quantitative Value**: **0.065 to 0.078**.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **0.065 to 0.078**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.0 marks).
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