Q.46 The following reaction represents biomass synthesis from hexadecane
C16H34 + 12.5O2 + 2.13NH3 → 10.6CH1.66O0.27N0.27 + 5.37CO2 + 11.4H2O
where CH1.66O0.27N0.27 represents the biomass. The value of respiratory quotient (rounded off to two decimal places) is ____________.
Reaction Analysis
The balanced equation is C16H34 + 12.5 O2 + 2.13 NH3 → 10.6 CH1.66O0.27N0.27 + 5.37 CO2 + 11.4 H2O, where CH1.66O0.27N0.27 formula represents biomass stoichiometry.
This depicts microbial growth on hexadecane (a hydrocarbon), with partial substrate diversion to biomass and partial oxidation to CO2 and H2O.
O2 acts as the electron acceptor, while NH3 supplies nitrogen for biomass.
RQ Calculation
RQ equals moles of CO2 produced divided by moles of O2 consumed: RQ = 5.37 / 12.5 = 0.4296.
Rounded to two decimal places, RQ = 0.43, typical for fat/hydrocarbon oxidation (RQ < 1, unlike carbohydrates at ~1).
No options are provided in the query, but this direct stoichiometric method applies universally—no alternatives like yield corrections are needed here.
SEO Optimized Content
Respiratory quotient biomass synthesis hexadecane processes show microbes converting hydrocarbons like C16H34 into biomass (CH1.66O0.27N0.27), CO2, and H2O under aerobic conditions. This respiratory quotient biomass synthesis hexadecane reaction from GATE BT 2023 Q.46 highlights bioprocess engineering principles for single-cell protein production.
Key Concepts
RQ Formula: RQ = (moles CO2 produced) / (moles O2 consumed), a dimensionless metric for substrate type and energy efficiency.
Significance: Low RQ (0.43 here) indicates lipid substrate oxidation, aiding yield predictions in fermentations.
Stoichiometry Breakdown
| Component | Coefficient | Role |
|---|---|---|
| C16H34 | 1 | Carbon/energy source |
| O2 | 12.5 | Electron acceptor |
| NH3 | 2.13 | Nitrogen source |
| Biomass | 10.6 | Product (10.6 moles) |
| CO2 | 5.37 | Respiration byproduct |
| H2O | 11.4 | Respiration byproduct |
Step-by-Step Solution for GATE Prep
- Identify CO2 and O2 from equation: 5.37 moles CO2, 12.5 moles O2.
- Compute RQ = 5.37 ÷ 12.5 = 0.4296.
- Round to 0.43 as specified.
This respiratory quotient biomass synthesis hexadecane value underscores incomplete oxidation in growth-linked metabolism, vital for IIT JAM/GATE Biotechnology aspirants tackling biokinetics.
