Section 4: Bioprocess Engineering and Process Biotechnology
Bioreactor types, scale-up
Subtopic: Fundamentals of Bioreactor types, scale-up
Question Statement:
In an exponentially growing batc h culture of Saccharomyces cerevisiae, the cell density is 20 gl -1
(DCW), the specific growth rate ( ) is 0.4 h -1 and substrate uptake rate ( ) is 16 gl -1h-1. The cell
yield coefficient Yx/s will be
(A) 0.32 (B) 0.64 (C) 0.80 (D) 0.50
Options:
(A) Q.32
(B) Q.64
(C) Q.80
(D) Q.50
Official Answer Key:
D
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2012 Q.29)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: BT
- **Question Type**: **MCQ** (2 Marks)
- **Core Topic**: Bioprocess Engineering
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Systematic Conceptual & Option-by-Option Evaluation**:
- Problem Focus: *"In an exponentially growing batc h culture of Saccharomyces cerevisiae, the cell density is 20 gl -1
(DCW), the specific growth rate ( ) is 0.4 h -1 and substrate uptake rate ( ) is 16 gl -1h-1. The cell
yield coeffi..."*
- **Option (D) [CORRECT]**: *"0.50"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"0.32"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (B) [INCORRECT]**: *"0.64"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (C) [INCORRECT]**: *"0.80"* does not satisfy the precise boundary conditions or molecular specificity.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **D**
- **Scoring Criteria**: 2 Marks (Negative marking: -0.66 marks).
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