Ginseng roots can be used to produce valuable secondary metabolites, particularlyginsenosides, in vitro. A batch culture of Panax ginseng roots is established in an air-drivenbioreactor to enhance ginsenoside production. The culture is maintained at 25°C with acontrolled nutrient supply. A nutrient medium containing 5% glucose and 2% NH₃ is preparedfor the culture, with the remainder of the medium considered water. Air at 25°C and 1 atmpressure is sparged into the reactor at a rate of 400 cm³ min⁻¹. Over a 30-day culture period,30,000 g of nutrient medium and 1000 liters of O₂ are supplied, while 300 liters of CO₂ arecollected in the off-gas. At the end of 30 days, 20,000 g of liquid medium remains, containing0.085% residual glucose and 1.6% dissolved NH₃. The ratio of fresh root weight to dry weight is10:1.(a) What dry mass of ginseng roots is produced in 30 days?(b) Write the reaction equation for ginseng root growth, indicating the approximatechemical formula for the roots, CHaObNδ.(c) What is the limiting substrate in this system?(d) What is the yield of ginseng roots from glucose?
Ginseng roots can be used to produce valuable secondary metabolites, particularly
ginsenosides, in vitro. A batch culture of Panax ginseng roots is established in an air-driven
bioreactor to enhance ginsenoside production. The culture is maintained at 25°C with a
controlled nutrient supply. A nutrient medium containing 5% glucose and 2% NH₃ is prepared
for the culture, with the remainder of the medium considered water. Air at 25°C and 1 atm
pressure is sparged into the reactor at a rate of 400 cm³ min⁻¹. Over a 30-day culture period,
30,000 g of nutrient medium and 1000 liters of O₂ are supplied, while 300 liters of CO₂ are
collected in the off-gas. At the end of 30 days, 20,000 g of liquid medium remains, containing
0.085% residual glucose and 1.6% dissolved NH₃. The ratio of fresh root weight to dry weight is
10:1.
(a) What dry mass of ginseng roots is produced in 30 days?
(b) Write the reaction equation for ginseng root growth, indicating the approximate
chemical formula for the roots, CHaObNδ.
(c) What is the limiting substrate in this system?
(d) What is the yield of ginseng roots from glucose?
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