Question

list two factors that determine the minimum growth temperature of a psychrophilic microorganism.

Answer 1

Psychrophilic microorganisms require a minimum temperature of - 20⁰C to 10⁰C to sustain. Fews spp. Of Arthrobacter, Psychrobacter, Pseudomonas are Psychrophilic.

The 2 factors that determine the minimum growth temperature of these organisms are:

1. Their enzyme specificity is at lower temperature only. Means they can sustain at lower temperature because they have enzymes as such which are functional only at the lower temperature.
2. Presence of unsaturated fatty acids in there plasma membrane make them susceptible to live in such cold conditions. Thus, transport across a membrane is not hampered at lower temperature.

Beside these, antifreeze proteins are also produced by these microscopic organisms that maintain the integrity of the DNA and helps in gene expression.