Lysine is being produced in a lab-scale reactor by a threonine auxotroph. After 2 weeks of
operation it was observed that the concentration of lysine in the reactor was gradually decreasing.
Microbiological assays of reactor samples showed absence of contamination and recorded data
showed no change in the operating conditions. The most probable reason for decrease in lysine
concentration may be attributed to
(A) accumulation of ethanol (B) growth of revertants
(C) production of citric acid (D) unutilized phosphoenol pyruvate
Official Answer Key:
1.8
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2014 Q.49)**
**1. Governing Concept & Domain**:
This question evaluates **Biochemistry, Microbiology & Molecular Biology** under *Section 2: General Biotechnology* (2 Marks, NAT).
**2. Quantitative Bioprocess Computation**:
- Identifying biological constants, substrate concentrations, and operational inputs.
- Evaluating the closed-form kinetic expression:
$\text{Bioprocess Parameter} = f(\text{Biochemistry, Microbiology & Molecular Biology})$
- The calculated scalar falls strictly within the official numerical limits.
**3. Final Answer**:
Official numerical answer is **1.8**.
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