Sarabjeet, If your isolated thermophilic organisms are spore formers then you can grow the culture to  their sporulation stage and store them either by soil stocks or glycerol stocks.

sir but my problem is that they are not growing at all....i will keep this point from next time 

For reviving of isolates which are preserved in Glycerol, empty all the contents from the tube into fresh sterile liquid medium and incubate at appropriate temperature and after incubation try pour or spread plate inoculation.

thank you so much sir for your guidance ....sir i did this and found growth in liquid medium but when from that media i tried to grew these organisms on plate then there was no growth on plate.....

May be u try to increase the incubation period, then transfer every 24hrs on the plate so you can know at what stage it grows and to be sure of it wount grow at all

i did this culture grew after 3 days but when i am trying to transfer it on plates it doesnt grew at all.....