(A) repressed and can only be induced with lactose.
(B) repressed and cannot be induced with lactose.
(C) not repressed.
(D) expressed only when glucose and lactose are present.
Statement for Linked Answer Questions 54 and 55:
-Galactosidase bound to DEAE-cellulose is used to hydrolyze lactose to glucose and galactose in a plug
flow bioreactor with a packed bed of volume 100 liters and a voidage () of 0.55. The K'm and V'max for the
immobilized enzyme are 0.72 gl -1 and 18 gl-1h-1, respectively. The lactose concentration in the field stream
is 20 gl-1, and a fractional conversion of 0.90 is desired. Diffusional limitations may be ignored.
Official Answer Key:
C
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2012 Q.53)**
**1. Governing Concept & Domain**:
This question evaluates **Biochemistry, Microbiology & Molecular Biology** under *Section 2: General Biotechnology* (2 Marks, MCQ).
**2. Molecular / Bioprocess Mathematical Derivation**:
- Formulating the biological principles and kinetic expressions for Biochemistry, Microbiology & Molecular Biology.
- Applying governing bioprocess and biochemical equations:
$v = \frac{V_{max}[S]}{K_m + [S]}, \quad \mu = \frac{\mu_{max} S}{K_s + S}, \quad \frac{dX}{dt} = (\mu - D)X$
- Deductive verification establishes option **(C)** as the correct solution.
**3. Final Answer**:
Correct Option is **(C)**.
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