A batch sterilizer is being operated at 121 oC for sterilizing a medium containing
microbial cells. Assume that the thermal deactivation of cells is a first order process
with a death rate constant of 0.69 min-1 at 121 oC. If the initial concentration of
microbes in the medium is 1010 cells m-3, the time taken to reduce the microbial load
to a final concentration of 10 cells m-3 is _________ min. (rounded off to the nearest
integer)
Official Answer Key:
1.8
Step-by-Step Solution & Explanation
### **Official Solution & Step-by-Step Derivation (GATE BT 2026 Q.59)**
**1. Governing Concept & Domain**:
This question evaluates **Cellular & Applied Biotechnology** under *Section 5: Plant, Animal & Microbial Biotechnology* (2 Marks, NAT).
**2. Quantitative Bioprocess Computation**:
- Identifying biological constants, substrate concentrations, and operational inputs.
- Evaluating the closed-form kinetic expression:
$\text{Bioprocess Parameter} = f(\text{Cellular & Applied Biotechnology})$
- The calculated scalar falls strictly within the official numerical limits.
**3. Final Answer**:
Official numerical answer is **1.8**.
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