Characterization of an extracellular lipase and its chaperone from Ralstonia eutropha H16

Lipase enzymes catalyze the reversible hydrolysis of triacylglycerol to fatty acids and glycerol at the lipid–water interface. The metabolically versatile Ralstonia eutropha strain H16 is capable of utilizing various molecules containing long carbon chains such as plant oil, organic acids, or Tween as its sole carbon source for growth. Global gene expression analysis revealed an upregulation of two putative lipase genes during growth on trioleate. Through analysis of growth and activity using strains with gene deletions and complementations, the extracellular lipase (encoded by the lipA gene, locus tag H16_A1322) and lipase-specific chaperone (encoded by the lipB gene, locus tag H16_A1323) produced by R. eutropha H16 was identified. Increase in gene dosage of lipA not only resulted in an increase of the extracellular lipase activity, but also reduced the lag phase during growth on palm oil. LipA is a non-specific lipase that can completely hydrolyze triacylglycerol into its corresponding free fatty acids and glycerol. Although LipA is active over a temperature range from 10 °C to 70 °C, it exhibited optimal activity at 50 °C. While R. eutropha H16 prefers a growth pH of 6.8, its extracellular lipase LipA is most active between pH 7 and 8. Cofactors are not required for lipase activity; however, EDTA and EGTA inhibited LipA activity by 83 %. Metal ions Mg[superscript 2+], Ca[superscript 2+], and Mn[superscript 2+] were found to stimulate LipA activity and relieve chelator inhibition. Certain detergents are found to improve solubility of the lipid substrate or increase lipase-lipid aggregation, as a result SDS and Triton X-100 were able to increase lipase activity by 20 % to 500 %. R. eutropha extracellular LipA activity can be hyper-increased, making the overexpression strain a potential candidate for commercial lipase production or in fermentations using plant oils as the sole carbon source.Malaysia-MIT Biotechnology Partnership Programm

Spectral gamma ray logging: A cost-effective method for uranium exploration

The most useful technique in uranium exploration program is undoubtedly radiometric surveys. This is due to the fact that uranium emits gamma rays ranging from as low as 47kev to 2.2Mev, which can be detected and quantified using suitable radiation detector. Combination of aerial radiometric surveys, ground examination of the detected anomalies, followed by drilling and gamma ray logging of drilled boreholes has resulted in the identification of large uranium resources. Borehole logging provides the most important subsurface information required for the uranium exploration program. An area known to contain only uranium, computed gamma ray logging with a Geiger Muller (GM) Detector rapidly gives the required subsurface radioactivity information whereas, in a heterogeneously mineralized area of uranium with thorium, logging data using GM detector may mislead to wrong interpretation. Under such condition, using the principle of gamma ray spectrometry, scintillation detector-based spectral gamma ray logging is carried out. Identifying uranium in the presence of thorium is a complex process and this paper deals with a case study on the spectral gamma ray logging carried out to locate the subsurface uraniferous zone in Pakkanadu area, Salem district of Tamil nadu, where the surface anomaly indicated the presence of high thorium content. The various limitations such as small detector size, large sample volume, high-correction factor required for quantifying the individual elements, and the study carried out for optimizing the time required for data acquisition are discussed

6V, 60Ah nickel-iron battery

High reversibility of the charge discharge reaction leads to the longest service life. The iron electrode has low hydrogen overvoltage. Its ionization potential and hydrogen evolution potential are very close in alkaline medium. As a result, the self discharge of this system is 1-2% of the nominal capacity at 300K [1]. The advanced Ni/Fe batteries with an energy density of 55-82 Wh/Kg [2,3] serve as power sources for electric vehicles. The electrode fabrication techniques and the performance characteristics of the 6V, 60Ah Ni/Fe battery are presented in this pape