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
Chitinase is one of the important enzymes as it is directly linked to Chitin that has wide applications in industrial, medical and commercial fields for its biocompatibility and biodegradability. Here, we report extracellular chitinase production by Streptomyces violascens NRRL B2700 under submerged fermentation condition. Chitinase production started after 10 h of incubation and reached to maximum level at 72 h of cultivation. Studies on the influence of additional carbon and nitrogen sources on chitinase production revealed that maltose, xylose, fructose, lactose, soybean meal and ammonium nitrate served as good carbon and nitrogen sources to enhance chitinase yield by 1.6 to 6 fold. Medium supplemented with 1% colloidal chitin produced high chitinase concentration (0.1714 U/mg). The enzyme chitinase was purified from the culture broth by 75% ammonium sulphate precipitation, DEAE-cellulose ion-exchange and sephadex G-100 gel filtration. The molecular mass of the purified chitinase was 65 kDa as estimated by SDS-PAGE. The apparent Michaelis constant (Km) and the maximum rate (Vmax) of the enzyme for colloidal chitin were 1.556 mg/mL and 2.680 µM/min/mg, respectively suggested high affinity towards chitin. Possibly, it is the first report on production of chitinase from S. violascens NRRL B2700. The findings were encouraging, especially for cost effective production, and further warrants media and purification optimization studies for enhanced yield.