⚗️ Biochemical Engineering Solved MCQs with Answers

Practice 513 approved ⚗️ Biochemical Engineering questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

513 solved MCQs

Formation of end product by Lactococcus lactis will become non-growth associated as lactic acid accumulates becauseAnswer: Cells will redirect ATP to the active transport of lactic acid and H+ out of the cells Which of the following would not be subjected to the "glucose effect"?Answer: Escherichia coli Immobilized cell reactors for wastewater treatment have the advantage of having/beingAnswer: All of these Which of the statement is true for continuous reactor at steady state?Answer: Biomass, substrate and product concentrations do not change with time A continuous bioreactor in which only the flow rate is used to control the rate of cell or product productivity is calledAnswer: Chemostat For organisms growing in a chemostat, the specific growth rateAnswer: Can be determined from the dilution rate Saccharomyces cerevisiae is being grown in a chemostat converts glucose to biomass, ethanol, glycerol and carbon dioxide. At steady state, the concentration of glucose, biomass, ethanol and glycerol willAnswer: Be constant In aerobic yeast fermentation for production of citric acid from alkanes using a fed-batch culture, why alkanes are slowly fed to the yeast?Answer: Fast addition of alkanes will inhibit the cells and reduce oxygen transfer rates A continuous reactor has a dilution rate of 0.5 h⁻¹. Its residence time would beAnswer: 2 h Which of the following is used to calculate mass of substrate in the reactor?Answer: Volume of reactor x substrate concentration in reactor If biomass yields are constant, then the biomass productivity of a culture grown in continuous reactor willAnswer: Increase with dilution rate until washout Low dissolved oxygen concentrations leads toAnswer: Low biomass yields In a continuous reactor, the medium contains 40 g.l⁻¹ of maltose and the medium flow rate is 10 litres per hour and the effluent contains 20 g.l⁻¹ of lactate. What is the productivity of lactate production from this reactor?Answer: 200 g lactate.l⁻¹ A fed-batch reactor containing 1 g.l⁻¹ of substrate in 2 litre of medium. It is fed with 1 g.l⁻¹ of substrate at the rate of 1 litre per hour. After 10 hours, the concentration of substrate in the reactor was 0.5 g.l⁻¹ . The mass of substrate that was used by the culture in the reactor wasAnswer: 6g Toxins accumulated in a reactor can lead to low biomass yields probably due to which of the following?Answer: ATP is diverted away from anabolism to homeostasis The cellular productivity in a continuous stirred tank fermenter (CSTF) increases with an increase in the dilution rate and reaches a maximum value. If the dilution rate is increased beyond the maximum point, the productivity willAnswer: Decrease abruptly Fluidized bed bioreactors provide higher mass transfer rates than packed bed bioreactors becauseAnswer: Particles move with the fluid in a fluidized bed bioreactor In fed-batch fermentation, mass of substrate utilized is calculated using the relationshipAnswer: Initial mass of substrate in the reactor - final mass of substrate in the reactor + flow rate x [substrate in the feed] A chemostat has a liquid volume of 2 litres and is being fed at a rate of 4 litres per hour. Dilution rate for this reactor will beAnswer: 2 h⁻¹ Mixing per unit volume is observed to be poorest inAnswer: Continuous packed bed reactor The growth of an organism on glucose is described by the following Monod model parameters: μm = 0.5 h⁻¹ and Ks =0.1 g.l⁻¹, if the concentration of glucose in the feed is 10 g.l⁻¹ and the dilution rate is set to 0.4 h⁻¹, then the steady state concentration of glucose in the effluent will beAnswer: 0.5 g.l⁻¹ A continuous reactor at steady state contains 0.04 g.l⁻¹ of biomass and 0.02 g.l⁻¹ of phenol. The feed contained 0.1 g.l⁻¹ of phenol. The biomass yield would beAnswer: 0.5 g.g⁻¹ A culture system with constant environmental conditions maintained through continual provision of nutrient and removal of wastes is called __________ culture system.Answer: Continuous The main reason for production of antibiotics in fed batch reactors isAnswer: All of these Fed batch reactors is used to produce vinegar becauseAnswer: It can maintain low ethanol concentrations When a culture of fermenting yeast becomes metabolically uncoupled, ethanolAnswer: Production becomes non-growth associated Mixing profiles closest to plug flow are observed inAnswer: Continuous packed bed reactor Unsteady state mass balance for dynamic model of continuous stirred tank reactor (CSTR) isAnswer: Time rate of total amount in rector = rate of addition to reactor -rate of removal + rate of formation A fed-batch reactor initially contains 2 litre of medium. If it was fed at 1 litre per hour, then after 10 hours, the volume of the reactor will beAnswer: 2 litre A Bacillus sp. produces an antibiotic only during the stationary phase when grown in a batch culture. If grown in a 5 litre continuous culture, the steady state productivity of the antibioticAnswer: Will be zero