1425 g nutrient medium containing 3% glucose and 1.75% NH3 is fed into the react

Question

1425 g nutrient medium containing 3% glucose and 1.75% NH3 is fed into the reactor; the remainder of the medium can be considered water. Air at 25°C and 1 atm pressure is sparged into the fermenter at a rate of 22 cm3 min -1. During a 10-day culture period, 47 liters O2 and 15 liter CO2 are collected in the off-gas. After 10 days, 1110 g liquid containing 0.063% glucose and 1.7% dissolved NH3 is drained from the vessel. The ratio of fresh weight to dry weight for roots is known to be 14:1.

(a) What dry mass of roots is produced in 10 days?

(b) Write the reaction equation for growth, indicating the approximate chemical formula for the roots, CHON.

(c) What is the yield of roots from glucose?

3. Plant roots produce valuable chemicals in vitro. A batch culture of Atrona belladonna roots at 25°C is established in an air-driven reactor as shown in the following figure Because roots cannot be removed during operation of the reactor, it is proposed to monitor growth using mass balances. Off-gas Nutrient medium Air-driven reactor Roots ir Drained liquid 1425 g nutrient medium containing 3% glucose and 1.75% NH3 is fed into the reactor, the remainder of the medium can be considered water. Air at 25°C and 1 atm pressure is sparged into the fermenter at a rate of 22 cm3 min1. During a 10-day culture period, 47 liters O2 and 15 liter CO2 are collected in the off-gas. After 10 days, 1110 g liquid containing 0.063% glucose and 1.7% dissolved NH3 is drained from the vessel. The ratio offresh weight to dry weight for roots is known to be 14:1 (a) What dry mass of roots is produced in 10 days? (b) Write the reaction equation for growth, indicating the approximate chemical formula for the roots, CHOsN (c) What is the yield of roots from glucose?

Explanation / Answer

From the given information, we can calculate mass and molar rates of glucose, ammonia, water into the bioreactor.

for glucose,

mass rate = 0.03 * 1425 = 42.75 g/run

molar rate = 42.75/180 = 0.2375mol/run

similarly for ammonia, mass rate = 24.94g/run and molar rate = 1.47 mol/run

for water, mass rate = 1357g/run and molar rate = 75.4 mol/run

hence, glucose is a limiting factor and not consumed compleately.

bioreactor sealed for 10 days so that biomass can not enter or leave the culture that leads in increase of mass as plant grows. therefore accumulation of mass, biomass = 0 - 0 + 3.37 * 0.2336 mol/run = 0.787 mol/run

in molar units biomass = 0.787 * 26.45 = 20.8g/run

hence, dry mass of roots is produced in 10 days = 20.8g/run.

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