STUDIES ON KINETIC PARAMETERS AND BIOCHEMICAL CHARACTERISTICS OF POLYPHENOL OXIDASE PURIFIED FROM JACKFRUIT (ARTOCARPUS HETEROPHYLLUS) WASTE

Objectives: Polyphenol oxidase activity was extensively studied in jackfruit for its role in enzymatic browning. PPO and the phenolic compound play a vital role in defensive mechanism against pest and diseases. Thus, to facilitate further studies in jack fruit waste, Polyphenol oxidase [PPO] was purified and characterized.Methods: Partial Purification of PPO from waste done through a sequential process of ammonium sulfate precipitation, dialysis and ion-exchange chromatography [DEAE- Cellulose]. Then the partially purified PPO was subjected to check various parameters like molecular weight and kinetic activity, the following characteristics of enzyme are checked: SDS-PAGE, pH, temperature, thermal stability, heat inactivation, metal ions, surfactants and inhibitor.Results: Purified PPO resulted in ~23 folds enriched in the specific activity of 1360 [µkat/mg] and it was found to be the monomer with a molecular weight of 63 kDa revealed by Coomasie Brilliant Blue staining. PPO exhibited optimum activity at pH 7.0 and temperature 20oC. PPO showed the maximum stability between pH 6.4- 7.6 at 10 oC - 40 oC. PPO showed the enzyme activity towards Diphenol> Triphenol> Monophenol, the substrate specificity was especially high towards the catechol at 0.1 M. The PPO activity was activated by Mn2+, Triton X- 100, EDTA, Sorbic acid and Citric acid, but inhibited by L- cysteine, Ascorbic acid, SDS, Cetyl trimethyl ammonium bromide [CTAB], K+, Zn2+, Ca2+ and Mg2+. Kinetic constant for PPO was found to be km= 15.82 mM and Vmax= 2182 U/ml min using catechol as substrate.Conclusion: Partial Purification of PPO from waste done through a sequential process of ammonium sulfate precipitation, dialysis and ion-exchange chromatography [DEAE- Cellulose]. The best substrate for PPO was identified as catechol [diphenol] and best inhibitor was L-cysteine and ascorbic acid. Â

Friction-wear behavior of shot peened aluminium 7075-T651 alloy

20-26The present study reports the friction-wear behavior of un-peened and shot peened aluminium 7075-T651 alloy against aluminium 7075-T651 alloy in dry sliding condition. Shot peening was done using CI steel ball (40-45 HRC) with 0.6 mm diameter. Phase Structure, hardness, compressive residual stress, surface morphology and surface features are characterized using X-ray diffractometer (XRD), Vickers hardness tester, noncontact-surface profile meter and scanning electron microscope (SEM). Sliding wear test were conducted against aluminium 7075-T651 alloy in dry sliding condition at room temperature using a pin on disc apparatus. A 25% increase in the hardness was seen for shot peened aluminium 7075-T651 alloy. Shot peened aluminium 7075-T651 alloy has induced maximum compressive residual stress of -188 MPa. No new phases were formed for the shot peened aluminium 7075-T651 alloy, however, the shift in the plane is observed. There was also a drastically increase in surface roughness in spite of the peening process. Adhesive wear was the dominant wear mechanism for the un-peened specimen, whereas, it was reduced for the shot peened surfaces

Processing of Carbon-Based Nanomaterials for the Removal of Pollutants from Water/Wastewater Application

In both the inorganic and organic worlds, carbon-based nanomaterials, such as benzene, diamond, graphite, fullerene, and carbon nanotubes, are abundant. In science laboratories, carbon is the focal point of activity. In this overview, the synthesis, characteristics, and several uses of graphene—including energy conversion, energy storage, electronics, and biosensing—were explored with a focus on ecologically friendly production techniques. This article also discusses recent advancements in the detection and treatment of organic contaminants and heavy metals utilizing nanomaterials. In this article, we outline some recent developments in the creation of innovative nanomaterials and nanostructures and methods for treating organic contaminants and heavy metals in water. The essay presents the current state of the field and, in our opinion, should be helpful to anybody interested in nanomaterials and related materials

Detection of magnetic dipole lines of Fe xii in the ultraviolet spectrum of the dwarf star ε Eri

We report observations of the dwarf star e Eri (K2V) made with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope. The high sensitivity of the STIS instrument has allowed us to detect the magnetic dipole transitions of Fe XII at 1242.00 and 1349 38 Å for the first time in a star other than the Sun. The width of the stronger line at 1242.00 Å has also been measured; such measurements are not possible for the permitted lines of Fe XII in the extreme-ultraviolet. To within the accuracy of the measurements the N v and the Fe XII lines occur at their rest wavelengths. Electron densities and linewidths have been measured from other transition region lines. Together, these can be used to investigate the non-thermal energy flux in the lower and upper transition regions, which is useful in constraining possible heating processes. The Fe XII lines are also present in archival STIS spectra of other G/K-type dwarfs