Showing papers by "Sathyanarayana N. Gummadi published in 2019"

Screening of new yeast Pichia manchurica for arabitol production

Abstract: Arabitol has several applications in food and pharmaceutical industries as a natural sweetener, dental caries inhibitor, and texturing agent. Newly isolated yeast strains from seawater, sugarcane plantation soil samples, and Zygosaccharomyces rouxii 2635 from MTCC were tested for arabitol production. The yield of arabitol was found to be higher in seawater isolate (24.6 g L-1 ) compared to two soil isolates (22.5 g L-1 ) and Z. rouxii (19.4 g L-1 ). Based on ITS 26S rDNA sequence analysis, the seawater isolate was identified as Pichia manchurica. In the present study, the effect of different substrates, trace elements, nitrogen sources, pH, and temperature on arabitol production was examined. Three different carbon sources viz. glucose, arabinose, and galactose were studied. Glucose was determined to be the best substrate for arabitol production (27.6 g L-1 ) followed by arabinose (13.7 g L-1 ) and galactose (7.7 g L-1 ). Maximum production of arabitol was observed at pH 6.0 (34.7 g L-1 ). In addition, arabitol production was high (35.7 g L-1 ) at temperature of 30 °C. Among the different concentrations of ammonium sulfate tested (3, 4.5, 6, 7.5, and 9 g L-1 ) concentration of 6 g L-1 resulted in higher arabitol Individual metal ions had no effect on arabitol production by this strain as compared to control. Results obtained in this study identify ways for improved arabitol production with natural isolates using microbial processes.

Characterization and health risk assessment of indoor dust in biomass and LPG-based households of rural Telangana, India.

Abstract: Indoor dust is one of the key sources contributing to indoor air pollution (IAP) in rural households. It acts as a media for various toxicants like heavy metal depositions and causes severe...

Cuprous Oxide- or Copper-Coated Jute Stick Pieces at an Air–Water Interface for Prevention of Aerial Contamination in Potable Water

Abstract: Cuprous oxide and copper have been synthesized via the solvothermal process using basic copper carbonate as the source of copper. Pure Cu2O or Cu could be afforded by simply varying the solvent while keeping the temperature and time constant. In this study, copper-based materials were coated on jute stick pieces (JSP) in situ. Cu2O-coated JSP (Cu2O-JSP) and Cu-coated JSP (Cu-JSP) were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). Cu2O-JSP and Cu-JSP were found to be active against Escherichia coli NCIM 2931 (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria). The antibacterial nature of the material and the buoyant nature of Cu2O-JSP and Cu-JSP were exploited to develop beaded necklace-like strands that could be floated on potable water to effectively prevent aerial contamination. Leaching of copper from both Cu2O-JSP and Cu-JSP into water was found to be below the permissible limit for copper in drinking water.

pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase.

Abstract: BACKGROUND pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry. OBJECTIVE The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase. METHODS Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase. RESULTS The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1. CONCLUSION The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0-7.0.