How does the environmental condition effect growth kinetic explain in detail?
Answers
Effects of environmental conditions on growth kinetics How environment conditions affect growth kinetics? Environmental conditions: temperature, pH and dissolved-oxygen concentration Temperature affects the performance of cells. Organisms can be classified in 3 groups: 1)Psychrophiles (T opt < 20°C) 2)Mesophiles (T opt = 20 to 50 °C) 3)Thermophiles (T opt > 50°C) As the temperature is increased toward optimal growth temperature, the growth rate approximately doubles for every 10 °C increase in temperature.
3 Above the optimal temperature range, the growth rate decreases and thermal death may occur. The net specific replication rate can be expressed by Eq. 9.19 (for temperature above optimal level): At high temperatures, the thermal death rate exceeds the growth rate, which causes a net decreases of viable cells. Both u R and k d vary with temperature according to the Arrhenius equation: Where Ea and Ed are activation energies for growth and thermal death. Ea (10-20 kcal/mol) Ed (60-80 kcal/mol) Thermal death is more sensitive to temperature changes than the microbial growth. Microbial growth
4 Product formation Temperature also affects product formation. Temperature optimum for product formation and growth is different. The yield coefficient (Yx/s) is also affected by temperature. Example: a single-cell protein production. When temperature above the optimum temperature, the maintenance requirements of cells increase, resulting a decrease in the yield coefficient. Temperature also affects product formation. Temperature optimum for product formation and growth is different. The yield coefficient (Yx/s) is also affected by temperature. Example: a single-cell protein production. When temperature above the optimum temperature, the maintenance requirements of cells increase, resulting a decrease in the yield coefficient. Rate-limiting step in fermentation At high temperatures, the rate of bioreaction might become higher than the diffusion rate, and the diffusion then would be the rate- limiting step. Example:An immobilized cell system. The activation energy of molecular diffusion =6 kcal/mol. The activation energy of most bioreaction is 10 kcal/mol. So diffusion limitation must be carefully considered in high temperatures At high temperatures, the rate of bioreaction might become higher than the diffusion rate, and the diffusion then would be the rate- limiting step. Example:An immobilized cell system. The activation energy of molecular diffusion =6 kcal/mol. The activation energy of most bioreaction is 10 kcal/mol. So diffusion limitation must be carefully considered in high temperatures
Explanation:
Changes in temperature have the biggest effect on enzymes and their activity, with an optimal temperature that leads to the fastest metabolism and resulting growth rate. ... Adaptation to the cold required evolution of specific proteins, particularly enzymes, that can still function in low temperatures.