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Culture of plantroots
Plant roots produce valuable chemicals in vitro. "A batch culture of Atropa belladonna roots at 25°C is established in an air-driven reactor as shown in Figure. Because rootscannot be removed during operation of the reactor, it is proposed to monitor growth using mass balances.

1425 g nutrient medium containing 3% glucose and 1.75% NH3 is fed into the reactor; theremainder 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. During a 10-day culture period, 47 litres 02 and 15 litres CO2 arecollected 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, CH∝OβNδ.
(c) What is the limitingsubstrate?
(d) What is the yield of roots from glucose?

Oxygen requirement for growth on glycerol
Klebsiella aerogenes is produced from glycerol in aerobic culture with ammonia as nitrogen source. Thebiomass contains 8% ash, 0.40 g biomass is produced for each g glycerol consumed, and no major metabolic products are formed. What is the oxygen requirement for this culture in mass terms?Product yield in anaerobic digestion
Anaerobic digestion of volatile acids by methane bacteria is represented by the equation: CH3COOH + NH3 → biomass + CO2 + H20 + CH4
(acetic acid)(methane)

The composition of methane bacteria is approximated by the empirical formula CH1.4O0.4N0.20. For each kg acetic acid consumed, 0.67 kgCO2 is evolved. How does the yield of methane under these conditions compare with the maximum possible yield?

Stoichiometry of single-cell protein synthesis
(a) Cellulomonas bacteria used as...