Zbornik - Društvo genetičara Srbije

26 ZBORNIK ABSTRAKATA III KONGRESA GENETIÈARA SRBIJE I-Pos-5
Subotica, 30. novembar - 4. decembar 2004.
IZOLACIJA I KARAKTERIZACIJA BAKTERIJA
MLEÈNE KISELINE IZ RADANSKOG SIRA
Nataša Jokoviæ 1 , Maja Vukašinoviæ 2 i Lj. Topisiroviæ 3
1
Tehnološki fakultet, Leskovac
2
Tehnološko-metalurški fakultet, Beograd
3
Institut za molekularnu genetiku i genetièko inenjerstvo, Beograd
Iz kravljeg i ovèijeg mleka kao i iz uzoraka sira tokom zrenja (5, 10, 20, 30 i 60 dana)
izolovano je 118 izolata bakterija mleène kiseline (BMK). Kao selektivna podloga
korišæene su: GM17 podloga za laktokoke, MRS podloga za laktobacile i MSE podloga
za leukonostoke. Na osnovu mikrobioloških i fizioloških testova izolati su identifikovani
do nivoa vrste. Vrste Lactococcus lactis subsp. lactis, Leuconostoc mesenteroides i
Enterococcus faecium izolovane su iz uzoraka mleka i sira, dok su vrste Lactobacillus
plantarum, Lactobacillus paraplantarum, Lactobacillus brevis i Eterococcus fecalis
izolovane samo iz sira. Korišæenjem mikrobioloških i fizioloških testova 20% izolata nije
bilo moguæe identifikovati. Analiza plazmidnog profila i ispitivanje proteolitièke
aktivnosti uraðeno je za 73 odabrana izolata. Veæina izolata Lactococcus lactis subsp.
lactis kao i homofermentativni laktobacili pokazuju dobru proteolitièku aktivnost, dok su
izolati iz rodova Leuconostoc i Enterococcus slabi proteoliti. Plazmidi su detektovani
kod veæine izolata i plazmidni profili pokazuju varijabilnost.
ISOLATION AND CHARACTERIZATION OF
LACTIC ACID BACTERIA FROM RADAN'S CHEESE
In this study we described characterization of 118 natural isolates of lactic acid bacteria
(LAB) from cow's milk, ewe's milk and cheese (samples were taken after 5, 10, 20, 30
and 60 days of ripening). The isolates were selected using selective media for LAB,
GM17 for lactococci, MRS for lactobacilli and MSE for leuconostoc. Identification of
strains to the species level was performed by the analysis of their carbohydrate fermentation
pattern and by their physiological characteristics. Lactococcus lactis subsp. lactis,
Leuconostoc mesenteroides and Enterococcus faecium were found in milk and cheese,
while Lactobacillus plantarum, Lactobacillus paraplantarum, Lactobacillus brevis and
Enterococcus faecalis were found only in cheese samples. Twenty percent of isolates
were not determinated by used tests. Isolation of plasmids and examination of proteolytic
activity were done for 73 isolates. The most strains of Lactococcus lacts subsp. lactis and
homofermentative lactobacilli exhibited high proteolytic activity towards b-casein, while
strains from genus Leuconostoc and Enterococcus showed weak proteolytic activity. The
analysis of plasmid profiles revealed that majority of strains containe different plasmids.