<prompt> Generation time of E-coli is20 days20 minutes20 hours20 second  <response>: 20 minute 271- Ananthanarayan 8th, 30- Chakrahorthy 2nd Many bacteria reproduce by binary fission and the average time required for the population, or the biomass, to double is known as generation time or doubling time.GENERATION TIME Lepra bacillus - 24 Days Tuberculous bacillus - 20 hours Coliform E.coli - 20 minute Clostridium - 10 minute Each bacterial colony in a solid medium consists of descendants of a single cell An ordinary bacterium doubles every 20-30 minutes and by geometric progression in exponential phase of growth thus a single bacterium can theoretically give rise to 1021 progeny in 24 hours roughly a ton of dry weight of bacterial cells. 