Removal of Ammonia from Wastewater Effluent by Chlorella Vulgaris

The capability of Chlorella vulgaris to remove nitrogen in the form of ammonia and/or ammonium ions from wastewater effluent in a local wastewater treatment plant (i.e., the Mill Creek Plant in Cincinnati, Ohio, U.S.A.) was studied. The wastewater effluent leaving the plant was found to include high concentra-tions of nitrogen (7.7±0.19 mg/L) (ammonia (NH3) and/or ammonium ion (NH4+)) and total inorganic carbon (58.6±0.28 mg/L) at pH 7, and to be suitable for growing Chlorella vulgaris. When Chlorella vulgaris was cul-tivated in a batch mode under a closed system, half of the nitrogen concentration was dramatically removed in 48 h after a 24-h lag-phase period. Total inorganic carbon concentration also concomitantly decreased during the rapid growth-phase. The total biomass weight gained during the entire cultivation period balanced out well with the total amount of inorganic carbon and nitrogen removed from the culture medium. These results indicate that wastewater can be synergistically used to polish residual nutrients in wastewater as well as to cultivate microalgae for biofuel production.     

Proton translocation by cytochrome c oxidase.

Cell respiration in mitochondria and some bacteria is catalysed by cytochrome c oxidase, which reduces O2 to water, coupled with translocation of four protons across the mitochondrial or bacterial membrane. The enzyme's catalytic cycle consists of a reductive phase, in which the oxidized enzyme receives electrons from cytochrome c, and an oxidative phase, in which the reduced enzyme is oxidized by O2. Previous studies indicated that proton translocation is coupled energetically only to the oxidative phase, but this has been challenged. Here, with the purified enzyme inlaid in liposomes, we report time-resolved measurements of membrane potential, which show that half of the electrical charges due to proton-pumping actually cross the membrane during reduction after a preceding oxidative phase. pH measurements confirm that proton translocation also occurs during reduction, but only when immediately preceded by an oxidative phase. We conclude that all the energy for proton translocation is conserved in the enzyme during its oxidation by O2. One half of it is utilized for proton-pumping during oxidation, but the other half is unlatched for this purpose only during re-reduction of the enzyme.     

Isolation and characterization of biologically active lectin from Korean mistletoe, Viscum album var. Coloratum

A mistletoe lectin was isolated from water extracts of Korean mistletoe, a subspecies of Viscum album, grown on Quercus mongolica using CM-Sepharose chromatography followed by an affinity chromatography on a concanavalin A-Sepharose column. The compound proved to be a mistletoe lectin II with D-galactose and N-acetyl-D-galactosamine specificity. Matrix-assisted laser desorption time-of-flight mass spectroscopy showed it to have an average molecular mass of 62.7 kDa and to consist of two subunits of 30.6 kDa and 32.5 kDa. It was a basic protein with isoelectric points of 9.4 and 9.6 by capillary isoelectric focusing and was cytotoxic to Molt4 cell. Received 17 November 1998; received after revision 3 March 1999; accepted 3 March 1999     

Effect of carbenoxolone on phosphodiesterase and prostaglandin synthetase activities.

Carbenoxolone inhibited in vitro cAMP and cGMP phosphodiesterases in a concentration-dependent and noncompetitive manner. Prostaglandin synthetase activity of rabbit kidney medulla was slightly stimulated by carbenoxolone 0.1--0.5 mM, but inhibited by higher concentrations.