Section 4: Bioprocess Engineering and Process Biotechnology
Bioreactor types, scale-up
Subtopic: Fundamentals of Bioreactor types, scale-up
Question Statement:
Wash out (as defined by D=max) of a continuous stirred tank fermenter is characterized by
(X=biomass, S=substrate concentration in bioreactor, So=substrate concentration in feed,
P=product concentration in bioreactor)
Options:
(A) X = 0, S = 0, P = 0
(B) X = 0, S = So, P = 0
(C) X = 0, S < 0, P = 0
(D) X <0, S <0, P <0
Official Answer Key:
B
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2011 Q.16)**
**1. Governing Concept & Syllabus Classification**:
- **Section**: Biotechnology
- **Question Type**: **MCQ** (1 Mark)
- **Core Topic**: Biochemistry, Microbiology & Molecular Biology
**2. Detailed Step-by-Step Analytical & Scientific Derivation**:
- **Systematic Conceptual & Option-by-Option Evaluation**:
- Problem Focus: *"Wash out (as defined by D=max) of a continuous stirred tank fermenter is characterized by
(X=biomass, S=substrate concentration in bioreactor, So=substrate concentration in feed,
P=product concentration in bioreactor)..."*
- **Option (B) [CORRECT]**: *"X = 0, S = So, P = 0"*
- Validated by canonical biochemistry/biotechnology literature. Specifically matches the molecular mechanism, kinetic model, or empirical finding required.
- **Option (A) [INCORRECT]**: *"X = 0, S = 0, P = 0"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (C) [INCORRECT]**: *"X = 0, S < 0, P = 0"* does not satisfy the precise boundary conditions or molecular specificity.
- **Option (D) [INCORRECT]**: *"X <0, S <0, P <0"* does not satisfy the precise boundary conditions or molecular specificity.
**3. Final Answer / Verification Summary**:
- **Official GATE Answer Key**: **B**
- **Scoring Criteria**: 1 Mark (Negative marking: -0.33 marks).
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