Tewari, LakshmiSharma, Raj Shekhar2018-06-212018-06-212017-06http://krishikosh.egranth.ac.in/handle/1/5810054757Two halo-alkalotolerant indigenous fluorescent Pseudomonas isolates (GFP2 and WDP2) and two fungal cultures (T. harzianum and T. asperellum SE6) were screened qualitatively and quantitatively for their in vitro siderophore producing abilities. Qualitative detection for siderophore production was done by CAS agar plate assay and ferric chloride test. Quantification of percent sid units in the culture filtrates was done spectrophotometrically at 630nm. The maximum sid units were recorded for bacterial isolate GFP2 (44.2%) while among the two fungal cultures T. asperellum showed significantly higher sid unit (20%) as compared to T. harzianum at 48 h. Culture medium was optimized for siderophore production, for bacterial cultures succinate medium was found optimum while for fungal cultures modified mineral salt medium was selected for siderophore production. Siderophore production was checked under alkaline (pH 7.5-10.5) and saline (0% - 10% NaCl) stress conditions. The fluorescent pseudomonas isolate GFP2 and T. harzianum showed siderophore production under different alkaline condition up to pH 10.5. All the four cultures showed saline stress tolerance retaining siderophore producing capacity up to 6 % NaCl concentration. Only one culture T. asperellum SE6 showed siderophore production and salt tolerance up to 10% NaCl. Siderophores produced by all the test microbial cultures were characterized as hydroxamate type by chemical test while based on spectral analysis they were further characterized as di-hydroxymate type. UV-visible spectral analysis indicated decrease in the intensity of siderophores peaks along with shift in λmax values for the siderophores synthesized by the cultures under both abiotic stress conditions. Extracellular protein profiling was also performed by Native and SDS PAGE. Enhancement of phosphorus and micronutrient availability through solubilization of fixed minerals forms (ferric phosphate and zinc phosphate) was also studied using Atomic Absorption Spectrophotometer. The cultures varied in there phosphorus solubilization potential but showing maximum solubilization of zinc phosphate. Maximum zinc concentration 32.3 µg mL-1 was recorded in case of T. asperellum SE6 and while maximum iron concentration was recorded in the culture filtrate of fluorescent Pseudomonas isolate WDP2.ennullThesis