Browsing by Author "Yogalakshmi, K. N."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Comparative Analysis of Laccase Immobilization on Magnetic Iron Nanoparticles using Two Activating Agents:EDAC and Cyanuric Chloride
    (Tamil Nadu Scientific Research Organization (TNSRO), 2016) Das, Anamika; Singh, Jatinder; Yogalakshmi, K. N.
    Surface modification improves the covalent bonding of enzymes onto the magnetic nanoparticles. The present study aims to evaluate the effect of surface activators (EDAC (1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide) and Cyanuric chloride) in immobilization of enzymes. Nanoparticles prepared by co-precipitation method ranged insize from 15-20 nm. The nanoparticles possessed crystalline property as confirmed by the XRD (X-ray powder diffraction) peaks. SEM-EDS (Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy) analysis of EDAC and cyanuric acid activated nanoparticles showed atomic sulphur percent of 0.08% and 0.02%, respectively. It is concluded that EDACwas more successful in loading more enzymes than cyanuric acid. Bradford estimation of the unbound protein after first wash for ENP-EDAC and ENP-CC was 29.1 μg/mL and 132.1 μg/mL, respectively. EDAC is a potential surface modifier for enzyme immobilization process.
  • Thumbnail Image
    Item
    Copper(II) Bioremoval by a Rhizosphere Bacterium, Stenotrophomonas acidaminiphila MYS1-Process Optimization by RSM Using Box–Behnken Design
    (Springer, 2017) Manohari; Singh, Jatinder; Yogalakshmi, K. N.
    A copper-tolerant bacterium strain MYS1 was isolated from Brass effluent-contaminated Cynodon dactylon rhizosphere and identified as Stenotrophomonas acidaminipila by 16S rRNA analysis. Bacterium culture was enriched in copper(II) supplemented nutrient broth. Bacterial potential for copper(II) bioremoval was investigated under optimized parameters. Three parameters—pH, temperature and copper(II) concentration—were optimized through response surface methodology (RSM). Box–Behnken design (BBD) with quadratic model was selected. Seventeen experimental runs were carried out to get the desired response. Model’s significance was confirmed by high R2 value (0.9941), low P value (<0.0001) and F value (131.32). Effect of different parameters on bioremoval of copper(II) was determined by response contour and surface graphs. Results showed that optimum values for copper(II) removal were obtained at pH (5.0), temperature (32.5 °C) and copper(II) concentration (250 mg/L). Under these optimized conditions, maximum bacterium growth (2.87 µg/mg) and copper(II) bioremoval (94.1%) were demonstrated after 120 and 168 h of incubation, respectively. High percentage of copper(II) removal at such a higher concentration confirmed the feasibility of bacterium Stenotrophomonas acidaminiphila MYS1 in copper bioremediation and industrial effluent treatment.
  • Thumbnail Image
    Item
    Copper-tolerant rhizosphere bacteria—characterization and assessment of plant growth promoting factors
    (Springer, 2017) Rathi, Manohari; Yogalakshmi, K. N.
    Remediation of heavy metal contaminated soil is a major problem or concern worldwide. Heavy metal accumulation in the soil is increasing day by day by industries, mines, agriculture, fuel combustion and municipal waste discharge. Such contaminated soils harbour a large number of resistant microbial populations. Screening and isolation of such microbes would be utilized for natural remediation of metal contaminated soils. Therefore, in the present study, highly copper-tolerant bacteria from rhizosphere soil of Cynodon dactylon grown in brass effluent contaminated soil were isolated and assessed for plant growth promoting factors. A total of 61 isolates were isolated from the rhizosphere of three contaminated sites. Six highly copper-tolerant isolates named as MYS1, MYS2, MYS3, MYS4, MYS5 and MYS6 were isolated through enrichment in copper containing nutrient broth. 16S rRNA analysis revealed that the isolates were from genera Stenotrophomonas and Brevundimonas and belong to classes Alpha Proteobacteriacea and Gamma Proteobacteriacea, respectively. Strain MYS1, MYS2 and MYS4 showed 95–99% similarity with Stenotrophomonas acidaminiphila, strain MYS3 and MYS5 showed 99 and 97% similarity with Stenotrophomonas maltophilia and Stenotrophomonas sp. Strain MYS6 showed 94% similarity with Brevundimonas diminuta. All the rhizobacteria showed plant growth promoting traits such as production of siderophores, indole acetic acid (IAA), phosphate solubilization and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. From this study, we can conclude that all the isolates possess copper resistance and potential for phytoremediation of copper polluted soils.