hi.....did my Ph.D on these amphizoic amoebae, Naegleria, acanthamoeba, hartmanella etc ......regarding the growth rate,the growth depends upon the culture media and the type of food (bacteria) being inoculated. takes about 8 days in winters for a rich growth, maintaining the it around 28-30 degrees centigrade on nutrient agar plates inoculated with e. coli bacteria.
Hi. I did my Master's thesis on this organism and am currently working on my Ph.D. also. In terms of growth rate, I kind of agree with Dr. Shukla. But that is assuming that you use a medium with bacteria. Basically, their doubling time is 21-24 hours, so 3-4 days to get a full cell sheet in a T25. To grow them axenically we used a mix of Balamuth's and Nelson's medium, that we creatively called "Mix medium". :-) (John and Howard, 1995)