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Theses

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2020 - 20213
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Subject: Microbiology × End date: 2021 × Start date: 2020 × Type: Thesis × Thesis Type: Ph.D ×
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Now showing 1 - 3 of 3
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    ThesisItemOpen Access
    Interaction of Sesbania rhizobia with different species of Sesbania and kharif legumes
    (CCSHAU, Hisar, 2020-11) Jeniffer Christeena Masih; Gera, Rajesh
    Sesbania is an important wild legume as it can grow in wide range of soils like alkaline, waterlogged and acidic soils. It has high nitrogen fixation properties due to its association with rhizobia in both root and stem nodules. Rhizobia from wild legume like Sesbania may function as excellent plant growth promoting bacteria.Therefore, the present research was carried out to study the interaction of Sesbania rhizobia with different species of Sesbania and kharif legumes. A total of 25 Sesbania rhizobial isolates, which includes five isolates each from Sesbania aculeata, S. sesban, S. grandiflora, S. rostrata (root nodulating and stem nodulating), were included in the present investigation. Out of which 21 rhizobial isolates were obtained from departmental culture collection and 4 rhizobial isolates were isolated from soils collected from different locations of India using trap plant method. All the rhizobial isolates were able to produce IAA and ammonia, however, 92, 48 and 48 % rhizobia had the ability for phosphate solubilization, bacteriocin and siderophore production, whereas, 60% of rhizobia were able to utilize ACC. All the rhizobial isolates showed the presence of nifH and nodC genes. Five rhizobial isolates namely SSKr(ii), SGMg, SAUd(i), SRKr(iv)/r and SRTn/s from each Sesbania species were selected on the basis of different plant growth promoting traits, nodulation efficiency and amplification of nodC and nifH gene, to study their effect on different Sesbania species, mungbean and pigeonpea under sterilized conditions. The rhizobial isolates; SRKr(iv)/r (root nodulation) and SRTn/s (stem nodulation) were found to be most efficient isolates on the basis of nodule number and fresh nodule weight in cross nodulation within Sesbania species and other legumes. These isolates were also tagged with gfp gene to study their colonization on different parts of Sesbania rostrata. Recovery of GFP marked strains from root, root nodules, stem and stem nodules was 95 to100%. However, recovery of gfp marked strains from the surface of root and root nodules varied from 92 to100% while on the surface of stem and stem nodules, it ranged between 25 to 33%. Rhizobial isolate; SRKr(iv)/r showed good nodulation efficiency in all four Sesbania species and pigeonpea as compared to other rhizobial isolates under unsterilized conditions. Nodule occupancy of GFP marked strains; SRKr(iv)/rGFP+ and SRTn/sGFP+ under unsterilized condition was found to be 33-54 and 92% in case of root and stem nodules, respectively of Sesbania rostrata.
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    ThesisItemOpen Access
    Application of biosurfactants in herbicide mobilization and nanoparticle synthesis
    (CCSHAU, Hisar, 2021-10) Sharma, Pankaj; Sangwan, Seema
    Present study traversed cheaper renewable raw material, butter waste for biosurfactant production by four yeasts, Meyerozyma guilliermondii YK20, M. guilliermondii YK21, M. guilliermondii YK22 and M. guilliermondii Y32 followed by its extraction in crude form designated as BS20, BS21, BS22 and BS32, respectively, using acid precipitation. The crude products were allocated to respective classes and subclasses of biosurfactants using advanced characterization techniques before exploring their application in herbicide mobilization and nanoparticle synthesis. Acid precipitation method was able to yield 11.19 (pH 3.5), 12.55 (pH 3.0), 15.13 (pH 3.5) and 18.64g/L (pH 4.0) of biosurfactant BS20, BS21, BS22 and BS32, respectively. The crude biosurfactants BS20, BS21, BS22 and BS32 were found retaining and concentrating the surfactant activity ascertained in the form of oil displacements amounted to 48.0, 48.0, 50.0 and 55.2cm, respectively, as oppose to corresponding values of 5.5, 6.0, 7.5 and 8.0cm generated by cell free supernatants prior to extraction. Agar double diffusion technique confirmed the anionic nature of all the four products. Zeta potential of 33.2, 39.6, 69.8 and 200 mV with negative polarity signified moderate to excellent stability in case of BS32, BS21, BS20 and BS22, respectively. The biochemical analysis revealed the presence of lipid, proteins and carbohydrate fractions in all the four biosurfactants, underlining lipid as the major constituent ranging from 42-54%. FTIR spectra of biosurfactants have shown the glycolipid nature of all the biosurfactants due to the presence of carbonyl group, O-H, C-H and C-O stretching vibrations. The NMR spectra further indicated the presence of sophorose moiety confirming sophorolipid subclass of all the biosurfactants. The SEM micrographs revealed the polymeric nature and long-range order of all the biosurfactants while EDX spectra indicated the dominance of carbon and oxygen showing the prevalence of carbohydrate and lipid moieties. None of the biosurfactants exhibited any toxicity against chickpea (HC-1) and wheat (WH-1105) or any antimicrobial activity towards common soil inhabitants. The application of biosurfactant BS32 as adjuvant to herbicide glyphosate produced similar mortality at lower doses (75% and 50% of recommended dose) as produced by the chemical surfactant at recommended doses in Chenopodium album and Rumex dentatus, thereby, conversing a role in dose reduction of herbicide under test. Biosurfactant BS32 has also been detected as a potential replacement to chemical surfactant in metsulfuron methyl formulation at the recommended dose. Biosurfactant BS32, at 0.5% concentration played as reducing as well as stabilizing agent in synthesizing ZnO nanoparticles with spherical morphology and average size of 7.04nm as evaluated using HR-TEM analysis.
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    ThesisItemOpen Access
    Characterization and mass production of chitosan from fungi
    (CCSHAU, Hisar, 2020-06) Aathira S. Kumar; Malik, Kamla
    Chitosan is a linear cationic biopolymer consisting of β (1-4) bonds between 2-amino-2- deoxy-D glucopyranose and 2-acetamido-2- deoxy-D-glucopyranose. It is non-toxic, biocompatible, biodegradable, antimicrobial agent and has high charge density which paves way for its numerous applications especially in the field of agriculture, food and pharmaceuticals. Chitosan, besides chitin, occurs in fungal cell walls particularly of Ascomycetes, Basidiomycetes and Zygomycetes. The enzymatic deacetylation of chitin is the major mechanism for synthesis of chitosan in fungi. Hence, the biological alternatives (fungi) have been used for chitosan production through fermentation technologies. Chitosan has broad antimicrobial spectrum to which gram-negative, gram-positive bacteria and fungi are highly susceptible. In the present study, characterization and mass production of chitosan from fungi was standardized fermentation conditions and determined its antimicrobial properties against pathogenic microorganisms. A total of 18 morphologically different fungal isolates, 17 bacteria and 3 actinomycetes were isolated on chitin agar medium. Out of which, only 6 fungal isolates (FC1, FC3, FC7, FC8, FC9 and FC 16), 2 bacterial isolates (BC 1 & BC 12) and 1 actinomycete (AC 1) showed positive results by production of yellow colour on the chitin agar media supplemented with p-nitroacetanilide as indicator. FC 3 was the most efficient fungal isolate with highest yield of chitosan (0.096 g/100ml). Maximum chitosan production (0.265 g/100ml) was observed at temperature (35˚C) and pH 5 after 96 h of incubation. Glucose (0.309 g/100ml) and yeast extract (0.332 g/100ml) severed as the best carbon and nitrogen source for highest production of chitosan from FC3. When the growth media supplemented with agro-industrial waste @1% paddy straw +1% glucose (w/v) the yield of chitosan (0.315 g/100ml) was increased. The fungal isolates (FC3) showed maximum chitosan production in submerged fermentation (0.533 g/10g paddy straw) as compared to solid state fermentation (0.182 g/10g paddy straw). Therefore, mass production of chitosan from fungal isolate FC 3 was carried out by submerged fermentation in a bioreactor (BioFloR 120) and the yield of chitosan was found to be 5.37 g/l. Further, the chitosan extracted from isolate FC 3 was estimated for degree of deacetylation and it was observed 88.5%. On the basis of morphological and molecular characterisation, the fungal isolate FC 3 was identified as Aspergillus flavus. The antibacterial activities of chitosan at different concentrations were examined against Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus and Xanthomonas. The maximum inhibition zone (8. 0 mm) was observed at 1000 ppm against Escherichia coli. Whereas, the highest percentage of inhibition was observed at 3000 ppm for Rhizoctonia solani (90.73 %) and Fusarium oxysporum (76.27%).