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Phenotypic and Genotypic diversity of obtained from fermented Lactobacillus plantarum vegetables of North North-East India.

Aishwarya, S. (2015) Phenotypic and Genotypic diversity of obtained from fermented Lactobacillus plantarum vegetables of North North-East India. PhD thesis, University of Mysore.

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Abstract

Lactobacillus plantarum belongs to phylum Firmicutes and to the family Lactobacillaceae and has been revealed to have high genomic diversity, versatility and flexibility. Lb. plantarum is facultative heterofermentative, microaerophilic and native to a variety of ecological niches such as fermented vegetables, meat, fish, dairy products, human gastrointestinal tract etc. Among lactic acid bacteria (LAB), especially Lb. plantarum belongs to an important group of bacteria.because of its economic importance. Also, Lb. plantarum has beenproven to be an ideal probiotic culture and commonly used as a starter organism in the fermentation of vegetable products as well as in improving the shelf life of the end product. Recently, it has been employed as a model system to study metabolic engineering in microbes as a food grade host. Because of the production of antimicrobial compounds and immunomodulating ability, the characterization of the several Lb. plantarum cultures isolated from different fermented vegetables has been investigated in the present study to observe their divergence. Diversity studies of Lb. plantarum isolates from fermented vegetables has not been worked upon much, and hence, this work holds a great scope of investigation. A total of 27 Lb. plantarum cultures obtained from different Indian fermented vegetables. These products were Gundruk (7), Khalpi (7), Sinki (9) and fermented bamboo shoot products (Soibum, Mesu, Eup and Hirring) (4). Two standards- Lb. plantarum MTCC1432 (isolated from fermented Gundruk), Acr2 (isolated from fermented carrot) and S11T (isolated from chicken intestine) were considered for comparison. The isolates were then subjected to microbiological examination by adopting several physiological and biochemical tests. The selected isolates were tentatively identified as Lb. plantarum. These isolates were further subjected to species-specific PCR with an amplicon size of 250 bp. The diversity among these strains was determined by RAPD (Random Amplified Polymorphic DNA) PCR. The RAPD profiling for the selected Lb. plantarum isolates were found to be divergent and showed different banding pattern. In the present study, the Gram positive rod shaped LAB, tentatively identified as Lb. plantarum cultures that gave an expected amplicon size of 250bp by species-specific PCR assay. These cultures were found to have different growth characteristics, such as, most of the cultures showed appreciable growth at 10º C, whereas mild growth at 45 º C was observed only for a few. The RAPD profiling and the dendogram suggested their divergence, indicating the presence of different subspecies of Lb. plantarum. The methodology followed in the present study helps in the rapid detection of new subspecies of Lb. plantarum of vegetable origin. Our study will provide new insights into Lb. plantarum with divergent phenotypic properties and possible genomic life-style (such as carbohydrate utilization, exopolysaccharide production, bacteriocin production and adaptability to different ecological niches), thus occupying a miscellaneous range of environmental niches. Further, novel Lb. plantarum cultures can be used as a starter culture for a suitable vegetable fermentation since it is a dominant microflora.

Item Type: Thesis (PhD)
Uncontrolled Keywords: Lactobacillus plantarum, Firmicutes, Indian fermented vegetables, lactic acid bacteria
Subjects: 600 Technology > 05 Chemical engineering > 04 Fermentation Technology
600 Technology > 08 Food technology > 23 Vegetables
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 05 Nov 2015 07:48
Last Modified: 05 Nov 2015 07:48
URI: http://172.16.1.6/id/eprint/11917

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