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Inhibition of Pathogenesis of E.Coli by Using Probiotic Lactic Acid Bacteria

Mr., Khalandar (2010) Inhibition of Pathogenesis of E.Coli by Using Probiotic Lactic Acid Bacteria. [Student Project Report]

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Abstract

This Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page.

Item Type: Student Project Report
Additional Information: In the present study four probiotic Lactic acid bacteria (LCR, LG, LCRA and LMR) and six food borne pathogens E.coli,Citrobacter sp, Shigella sp, Pseudomonas sp, S. paratyphi and V.cholerae were taken. Gram staining of all the 8 cultures was performed. It showed that the LAB cultures were gram positive bacilli and the pathogens were all gram negative. The cultures LG and LCR were selected among the 4 cultures based upon their growth rate. Screening of the cultures was conducted by performing antimicrobial activity where inhibition activity of all the 4 LAB cultures was tested against all the 6 pathogens and LCR showed good activity against E.coli hence both of them were used for this study. The next step was to select the culture of particular growth phase which had the best activity than the other growth phases for this initially growth phase and generation time was performed to know the duration of lag, log, stationary and decline phases of both LCR and E.coli. Then the antimicrobial activity was performed by taking different growth phase of LCR against different growth phase of E.coli. The log phase of LCR showed good antimicrobial activity against the log phase of E.coli. Hence, log phase of both the LCR and E.coli was selected. Then strain improvement of LCR culture was done by subjecting it for chemical mutagenesis i.e. by using Ethyl methyl sulphonate (EMS) for different time duration. It shows a reduction in survival rate at 90 sec (40μl) mutagen exposure. Maximum survival was found with 10 sec exposure of EMS where as maximum antimicrobial activity was found(20 mm) in mutant exposed to 90 sec mutagen EMS. The activity was increased 1.33 folds as a compared to the control (15 mm).On the other hand the LCR culture was also exposed for UV. UV mutation of culture shows a reduction in survival rate at 15 sec UV exposure. Maximum survival was found with 5 sec exposure of UV where as maximum antimicrobial activity was found (15mm) in mutant exposed to 15 sec UV.The activity was increased 1 folds as a compared to the control (15 mm).Later co-culturing of LCR was done along with E.coli and number of cfu/ml of E.coli was reduced when compared with the cfu/ml obtained before co culturing. The effect of digestive enzymes-pepsin and trypsin and the percentage of survival was 3.86% and 1.45% respectively. RP-HPLC chromatographic method reveals that the fraction showed 2 peaks at 17 min and 34 min.the peak no 1 collected fraction showed the maximum zone of inhibition against E.coli hence this fraction is preferred for further analysis.
Uncontrolled Keywords: Lactic acid bacteria; Probiotic; food borne pathogens; E.coli
Subjects: 600 Technology > 08 Food technology > 09 Food Microbiology
500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 12 Jul 2010 09:35
Last Modified: 28 Dec 2011 10:16
URI: http://ir.cftri.com/id/eprint/9522

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