ABSTRACT
Natural sources, particularly microbes yield active molecules that have wide application in food and pharmaceutical industries, degradation of hazardous bacterial biofilms, etc. Safety and acceptability of such drugs attract researchers’ attention for new drug discovery. Here, we explored biologically active microbial strains having therapeutic applications isolated from five different geographical areas of India. On screening, we found 10 strains capable of producing chitinase (Chi), seven cholesterol oxidase (COD), five glutaminase (Gln) and two heparinase (Hep) producing strains. Most of the isolated strains were found to be actinomycetes. Morphological and biochemical characterization of the strains suggest that the selected 13 isolates belong to the genus Streptomyces. Out of which, four were characterized through 16S ribosomal RNA gene analysis as Streptomyces xanthochromogenes MTCC 11937 (S1), Streptomyces violascens (N1), Streptomyces xanthopheus MTCC 11938 (H1) and Streptomyces rimosus MTCC 10792 (Ay). Results suggest that the soil isolated Streptomyces strains continue to act as a fascinating source of clinical and commercially importance enzymes. Partially purified enzymes were found to possess a broad range of pH and temperature stability indicating their capability to be used in clinical and pharmaceutical fields.
ABSTRACT
Seasonal changes in abundance of nitrifiers (ammonia-oxidizing and nitrite-oxidizing bacteria) in surface and bottom water of freshwater ponds were examined with respect to temperature, DO, pH as well as concentration of ammonia and nitrite. The most probable number (MPN) of ammonia-oxidizers in different ponds varied from 1297±3.6 to 1673.23±0.36 ml-l in bottom and 720.5±8.1 to 955.3±10.8 ml-l in surface water during the rainy season while the MPN ranged from 1074±1.07 to 1372.17±4.6 ml-l in bottom and 515±10.1 to 678±11.8 ml-l in surface water in winter. However, the MPN were greatly reduced in summer and ranged from 435.05±15.7 to 547.54±2.12 ml-l in bottom and 218.7±7.3 to 368.4±9.32 ml-l in surface water. Similar seasonal trends were also observed in MPN of nitrite-oxidizers. Among all the physico-chemical parameters, abundance of nitrifiers was more positively correlated with ammonia and nitrite concentration in all the seasons. The abundance of nitrifiers in surface and bottom water was highest in rainy season followed by winter and modest in summer. The potential nitrification activities and oxidation rates were shown to be linear and activity of ammonia-oxidizing and nitriteoxidizing bacteria was highest during rainy season.