Kefir has got a lot of bacteria and yeasts that can be used as starter bacteria. If you follow the thermophilic starter procedures and use Kefir instead of fresh milk, you would be getting a good and strong culture ecosystem.
Strain about 1 litre of Kefir (separate the gems) and use your yogurt maker or keep the temperature about 43C to 50C. This will eliminate most of the mesophilic cultures and some yeast.
When it is curdled like yogurt (about a day or 2) separate 500ml and mix it with 500ml skimmed pasteurised milk. Put in your temperature controlled yogurt maker and keep it 43C to 50C constant till it curdles again.
If you do this for 7 to 10 times, you will get a strong thermophilic ecosystem with lots of different thermo bacteria.
I wonder what type of yeast can be left active after this process.
The known types of bacteria in Kefir are listed below. The bold ones are thermophilic bacteria (if I am not mistaken).
LACTOBACILLI
• Lactobacillus acidophilus
• Lb. brevis [or Lb. kefiri]
• Lb. casei subsp. casei
• Lb. casei subsp. rhamnosus
• Lb. paracasei subsp. paracasei
• Lb. fermentum
• Lb. cellobiosus
• Lb. delbrueckii subsp. bulgaricus
• Lb. delbrueckii subsp. lactis
• Lb. fructivorans
• Lb. helveticus subsp. lactis
• Lb. hilgardii
• Lb. helveticus
• Lb. kefiri
• Lb. kefiranofaciens subsp. kefirgranum
• Lb. kefiranofaciens subsp. kefiranofaciens
• Lb. parakefiri
• Lb. plantarum
STREPTOCOCCI/LACTOCOCCI
• Streptococcus thermophilus
• St. paracitrovorus
• Lactococcus lactis subsp. lactis
• Lc. lactis subsp. lactis biovar. diacetylactis
• Lc. lactis subsp. cremoris
• Enterococcus durans
• Leuconostoc mesenteroides subsp. cremoris
• Leuc. mesenteroides subsp. mesenteroides
• Leuc. dextranicum
YEAST
• Dekkera anomala t/ Brettanomyces anomalus a
• Kluyveromyces marxianus t/ Candida kefyr
• Pichia fermentans t/ C. firmetaria
• Yarrowia lipolytica t/ C. lipolytica
• Debaryomyces hansenii t/ C. famata
• Deb. [Schwanniomyces] occidentalis
• Issatchenkia orientalis t/ C. krusei
• Galactomyces geotrichum t/ Geotrichum candidum
• C. friedrichii
• C. rancens
• C. tenuis
• C. humilis
• C. inconspicua
• C. maris
• Cryptococcus humicolus
• Kluyveromyces lactis var. lactis
• Kluyv. bulgaricus
• Kluyv. lodderae
• Saccharomyces cerevisiae
• Sacc. subsp. torulopsis holmii
• Sacc. pastorianus
• Sacc. humaticus
• Sacc. unisporus
• Sacc. exiguus
• Sacc. turicensis sp. nov
• Torulaspora delbrueckii t
• Zygosaccharomyces rouxii
(http://4.bp.blogspot.com/_lgpO5erOGtw/SwPulxknkOI/AAAAAAAAAHM/to9S8X1mhB4/s1600/kefir4.jpg)
Kefir Grains or AKA Kefir Gems
(http://2.bp.blogspot.com/_lgpO5erOGtw/SwPuxK8M7zI/AAAAAAAAAHc/LjaNcDEM28g/s1600/kefir6.jpg)
Kefir Gems are ready for next batch