GATE BT 2020 • Q29 NAT • 1 Mark

Section 4: Bioprocess Engineering and Process Biotechnology

Bioreactor types, scale-up

Subtopic: Fundamentals of Bioreactor types, scale-up

Question Statement:

The elemental composition of dry biomass of a yeast species is CH1.600.4N0.250.0024Po.017. The contribution of carbon to the dry biomass is % (round off to 2 decimal places). [Given: atomic weights of H, C, N, O, P and S are 1, 12, 14, 16, 31 and 32, respectively] Q. No. 20 Solvents A and B are completely immiscible. Solute S is soluble in both these solvents. 100 g of S was added to a container which has 2 kg each of A and B. The solute is 1.5 times more soluble in solvent A than in solvent B. The mixture was agitated thoroughly and allowed to reach equilibrium. Assuming that the solute has completely dissolved, the amount of solute in solvent A phase is 8.

Official Answer Key:

51.01 to 52.99

Step-by-Step Solution & Explanation

### **Official Solution & Step-by-Step Derivation (GATE BT 2020 Q.29)** **1. Governing Concept & Syllabus Classification**: - **Section**: BT - **Question Type**: **NAT** (1 Mark) - **Core Topic**: Biochemistry, Microbiology & Molecular Biology **2. Detailed Step-by-Step Analytical & Scientific Derivation**: - **Mathematical & Quantitative Formulation**: - Problem Statement: *"The elemental composition of dry biomass of a yeast species is CH1.600.4N0.250.0024Po.017. The contribution of carbon to the dry biomass is % (round off to 2 decimal places). [Given: atomic weights of H, C, N, O, P and S..."* - Identifying governing bioprocess / mathematical relation: - In a continuous stirred tank bioreactor (chemostat) at steady state: $\mu = D = \frac{F}{V}$ where $\mu$ is the specific growth rate ($ ext{h}^{-1}$), $D$ is the dilution rate, $F$ is volumetric feed flow rate, and $V$ is working volume. $S = \frac{K_s D}{\mu_{max} - D}, \quad X = Y_{X/S}(S_0 - S)$ - **Calculated Quantitative Value**: **51.01 to 52.99**. **3. Final Answer / Verification Summary**: - **Official GATE Answer Key**: **51.01 to 52.99** - **Scoring Criteria**: 1 Mark (Negative marking: -0.0 marks).

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