Any x-phile has its optimum temperature range in the specified ranges. And, many times, it can only grow on the specified range

Any x-tolerant has its optimum in another range (usually mesophiles) but can grow on the specified growth ranges.

The definitions can vary a bit depending on the author, specially in the cases where a given organism can grow in more than one of the temperature ranges.

In any case, if you are investigating the temperature growth profiles and for example you see grow (in a mesophile) at 10° C but not at 4° C  on the specified incubation time, it is always worth to leave the 4° C longer, as the growth rate can be substantially diminished out of the optimum range.

Hope this helps.

Thank you 'Mr. Xabier Vázquez Campos' for your contribution. But can you answer about the TDP? Is this necessarily necessary to determine TDP as I mentioned in my question??

No, as said, the limits are established based on growth not on the death of the organisms.

Thank you 'Mr. Xabier Vázquez Campos'.

centrifugation

Thank you Dr. FA Dahalan. But how "centrifugation"? Can you explain?

Based on the information, I would assume it is a psychrophile (assuming 5C is it's optimal temperature). Also it seems it may be mesotolerant organism, however to be sure, I would lower the temperature from 40C to 20C as 40C seems to be too harsh on the organism in question.

Hope this helps!

I understand that there is no single parameter which can help to segregate these groups of bacteria. This conclusion is wiht the literature available now. I used a polyphasic approach where I compared

1. Days taken for colony formation on agar plate

2. FAME analysis for fatty acids

3. Temperature range of growth

the results were put together and proposed . Right now I cannot give you the reference as the MS is under the process of publication and I cant put the part of publication online

However, incase of few groups of bacteria there is PCR and other enzyme techniques. The publicationsare given below. If you cant find these articles, pls inform.

Francis KP, Mayr R, von Stetten F, Stewart GS and Scherer S (1998) Discrimination of psychrotrophic and mesophilic strains of the Bacillus cereus group by PCR targeting of major cold shock protein genes. Appl Environ Microbiol 64(9):3525–3529

Selbmann L, Zucconi L, Ruisi S, Grube M, Cardinale M and Onofri S (2010) Culturable bacteria associated with Antarctic lichens: affiliation and psychrotolerance. Polar biology 33: 71-83

Stetten FV, Francis KP, Lechner S, Neuhaus K and Scherer S (1998) Rapid discrimination of psychrotolerant and mesophilic strains of the Bacillus cereus group by PCR targeting of 16S rDNA. J Microbiol Methods 34(2) 99-106

Use of gel electrophoresis for the study of enzymatic activities of cold-adapted bacteria. Berchet V1, Boulanger D, Gounot AM.  J Microbiol Methods. 2000 Mar;40(1):105-10.

Also find attached a short lab- personal review which I made for myself. Hope these were of some use. 

Just plot the growth curve of the culture in the most appropriate temperature, in the Batch culture mode.

Thank you Dr. Michael Kitching, Dr. Jai Ghosh for nice contributions.

Dr. Parthiban Subramanian, I downloaded all the references you given. Now I am going through all those papers. Extremely thanks for your valuable contributions.