The present study is aimed at assessing the ability of metal resistant yeast, Loddermyces elongisporus, to uptake metal from liquid medium. The minimum inhibitory concentration of Cu(2+) against Loddermyces elongisporus ranged between 2.2-2.3 mg/l. The yeast could also tolerate Zn(2+) (2.9 mg/l), Hg(2+) (2.4 mg/l), Ni(2+) (2.2 mg/l), Cr(6+) (2.0 mg/l), Pb(2+) (1.1 mg/l), and Cd(2+) (0.8 mg/l). The yeast isolate showed typical growth curves but lag and log phases extended in the presence of copper. Yeast isolate showed optimum growth at 30 degrees C and pH 8. Metal processing ability of the isolate was determined in a medium containing 0.1 mg/l of Cu(2+). Loddermyces elongisporus could reduce Cu(2+) 15%, 26%, 39%, 50%, 60%, 67%, 75% and 81% from the medium after 6, 12, 18, 24, 30, 48, 72 and 96 hours, respectively. L. elongisporus could also efficiently remove 80% copper from the medium after 96 h and was able to remove Cu(2+) 60% and 77% from the wastewater after 4 and 8 d, respectively. The metal binding ability suggests possibility of using this yeast strain for removal of copper from metal contaminated wastewater.

Stress corrosion cracking behavior of quenched and tempered 2.25Cr 1Mo steel T Manzoor, E Ahmad, M Sarwar et al. Abstract. Duplex stainless steel having attractive combination of austenitic and ferritic properties is being used in industry such as petrochemical, pulp and paper mills. In this study, the corrosion and stress corrosion behavior of duplex stainless steel in 3.5% sodium chloride environment was investigated by weight loss measurements, electrochemical DC testing and slow strain rate test (SSRT). Weight loss data showed no significant corrosion after 1700 hours. Electrochemical polarization test in 3.5% NaCl solution exhibited a uniform corrosion rate of 0.008 mpy (calculated using Tafel analysis) showing passivity in the range of 735-950 mV. A comparison of the slow strain rate test in 3.5% NaCl solution with air shows almost a similar stress strain curve for duplex stainless steel. In comparison, the stress strain curves for 0.15% carbon steel show a loss of about 25% tensile elongation for the same comparison. The excellent corrosion and especially resistance to localized corrosion (pitting) is responsible for no loss of ductility in duplex stainless steel.

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