# DBT JRF 2020 — Question 30

Exam: DBT JRF 2020 · Section: B · Topic: Bioprocess Engineering · Difficulty: Hard

## Question

In an exponentially growing batch culture of Saccharomyces cerevisiae, the cell density is 30 $gL^{-1}$ (DCW), the specific growth rate ( $\mu$ ) is 0.4 $h^{-1}$ and substrate uptake rate (q) is 18 $gL^{-1}h^{-1}$ . The cell yield coefficient $Y_{X/S}$ will be

## Options

- **A.** 0.50
- **B.** 0.45
- **C.** 0.32
- **D.** 0.67

## Answer

Option D

## Explanation

Vaccines can be classified by the antigen used: Whole-pathogen vaccines (attenuated/inactivated): Oral Polio Vaccine/OPV (Sabin) = live-attenuated poliovirus; Hepatitis A vaccine (Havrix, Vaqta) = inactivated HAV; Rotavirus vaccine (Rotarix, RotaTeq) = live-attenuated rotavirus strains. Tetanus vaccine = tetanus TOXOID (formaldehyde-inactivated tetanus toxin/exotoxin) — NOT a whole pathogen. Toxoid vaccines (tetanus, diphtheria) use only the inactivated toxic protein, not the bacterium itself. Therefore tetanus vaccine does NOT belong to the 'whole pathogen attenuated/inactivated' category.

Source: https://mypyqbuddy.com/questions/in-an-exponentially-growing-batch-culture-of-saccharomyces-6a05a8a02adafec470293236