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The IIS University (2014)

Characterization of amylolytic and cellulolytic actinomycetes of salterns of Sambhar lake, Rajasthan

Sharma, Charu

Titre : Characterization of amylolytic and cellulolytic actinomycetes of salterns of Sambhar lake, Rajasthan

Auteur : Sharma, Charu

Université de soutenance : The IIS University

Grade : Doctor of Philosophy (PhD) 2014

Résumé partiel
Actinomycetes are Gram positive filamentous bacteria well known for the production of bioactive compounds. They also contribute to cycling of nutrient elements by producing extracellular hydrolytic enzymes. Amylase and cellulase are two important enzymes that are used in food, beverages, detergent, textiles, paper, pharmaceutical and biofuel industries. The demand for enzymes functional at high pH, temperature and salt concentrations is increasing day by day which emphasizes on the need of isolation of enzyme producing actinomycetes from extreme habitats. In order to suffice this demand a saline habitat of Rajasthan, Sambhar salt lake was investigated for its actinomycete population and the enzymes produced by them. This lake forms a unique ecosystem divided in to salterns that possesses wide range of salinities in its waters and is used for salt production. Water samples were collected from salterns in rainy, winter and summer season and analyzed for its pH and salinity content. Actinomycetes were isolated on actinomycetes isolation agar medium supplemented with NaCl. All the isolates were characterized on the basis of morphological features and biochemical tests whereas phylogenetic analyses were conducted for only a few isolates. These isolates were screened for their ability to produce extracellular amylase and cellulase enzymes by agar plate assays and the isolates that showed maximum enzyme productions were selected for optimization of culture conditions in submerged fermentation. A total of sixteen colonies of actinomycetes growing at wide range of salinity were isolated from water samples. They were proposed to be identified as members of genera Streptomyces, Nocardiopsis, Pseudonocardia, Saccharopolyspora, Microbispora, Actinobacterium, Kokuria and Georgenia on the basis of phenotypic and phylogenetic analysis. Thirteen isolates were found to produce both the enzymes as evident by hydrolysis observed on starch and CMC agar plates. The relative enzyme activity of all positive isolates was compared on media plates and the isolate SSL 6 (Actinobacterium sp.) and SSL 14 (Nocardiopsis sp.) producing maximum amylase and cellulase enzyme respectively were studied for culture conditions optimization.

Mots clés : Actinomycetes, Amylase, Antibacterial, Cellulase, Halophiles, ISP, Nocardiopsis, Phylogeny, Streptomyces, Sambhar Salt Lake.

Présentation et version intégrale (Shodhganga)

Page publiée le 26 février 2021