Studying of physiological, biochemical, plasmid DNA and protein profiles of some lactic acid bacteria

vuı Science Code: :216 Key Words : Lactic acid bacteria, protein profile, bioplastic (PHB) production, antimicrobial activity, plasmid DNA. Page Number :158 Adviser: :Prof. Dr. Yavuz BEYATLIvu nitrogen resource (34.71%). However, the maximum (23.70%) PHB production in combine medium (sucrose+peptone) was observed in Str. thermophilus Ba21S strain. Among the strains, Str. thermophilus Ba21S which had showed high PHB production was selected for mutation studies. N-methile-3-nitro-l- nitrosoguanidine as chemical mutagen and UV irridiation at 254 nm was selected as physical mutagen. The PHB production by parent and mutant strains were determined. However, the amount of PHB in mutant strains were lower than parent strain. Leu. cremoris BILeu, Lb. heh/eticus HylL, Str. thermophilus Ba21S and Lac. diacetylactis P-90 strains were selected for economical production of PHB by using sugar beet molasses and whey. It was determined that the PHB production by the strains in whey were higher than PHB production in control medium. The PHB production in whey medium was 15.29%, 10.20%, 36.59%, 18.98%. Str. thermophilus Ba21S and Lac. diacetylactis P-90 strains had showed less growth in molasses medium. For this reason, 2% glucose was added to molasses (0.5%, 1%, 1.5% and 2%) and the growth and PHB production of the cultures were investigated. However, the amount of PHB produced by the former bacteria was increased by the increasing molasses concentration. The latter bacteria were uneatable to produce PHB in the media mentioned. The general inhibition and bacteriocin activity of lactic acid bacteria on the test bacteria were investigated by using agar diffusion method. Micrococcus flavus and Micrococcus lutetts were more affected than other the test bacteria for inhibitory effects of LAB. None of the LAB strains were found to have a bacteriocin activity on the test bacteria. Plasmid DNA profiles of lactic acid bacteria were determined and their molecular weights were found. Results indicated that thirty strains were carried plasmids and their molecular weights were ranged from 1.83 to 28.07 kb. Other strains were not carried any plasmid DNA.vuı Science Code: :216 Key Words : Lactic acid bacteria, protein profile, bioplastic (PHB) production, antimicrobial activity, plasmid DNA. Page Number :158 Adviser: :Prof. Dr. Yavuz BEYATLI