An integrated algal sulphate reducing high rate ponding process for the treatment of acid mine drainage wastewaters.

Acid mine drainage pollution may be associated with large water volume flows and exceptionally long periods of time over which the drainage may require treatment. While the use and role of sulphate reducing bacteria has been demonstrated in active treatment systems for acid mine drainage remediation, reactor size requirement and the cost and availability of the carbon and electron donor source are factors which constrain process development. Little attention has focussed on the use of waste stabilisation ponding processes for acid mine drainage treatment. Wastewater ponding is a mature technology for the treatment of large water volumes and its use as a basis for appropriate reactor design for acid mine drainage treatment is described including high rates of sulphate reduction and the precipitation of metal sulphides. Together with the co-disposal of organic wastes, algal biomass is generated as an independent carbon source for SRB production. Treatment of tannery effluent in a custom-designed high rate algal ponding process, and its use as a carbon source in the generation and precipitation of metal sulphides, has been demonstrated through piloting to the implementation of a full-scale process. The treatment of both mine drainage and zinc refinery wastewaters are reported. A complementary role for microalgal production in the generation of alkalinity and bioadsorptive removal of metals has been utilised and an Integrated 'Algal Sulphate Reducing Ponding Process for the Treatment of Acidic and Metal Wastewaters' (ASPAM) has been described.

Semi-preparative purification of recombinant human renin and prorenin.

Chinese hamster ovary (CHO) cells, transfected with a vector containing cDNA coding for preprorenin, have been shown to secrete authentic prorenin into the culture supernatant. Purification of the expressed prorenin and purification of active renin, generated by solid-phase trypsin treatment of the conditioned media, have been achieved by conventional chromatographic methods. Scale-up of the initial steps of these procedures is described, including the use of radial-flow columns and automation with fast protein liquid chromatography valves and pumps. This semi-preparative scheme has allowed hundreds of milligrams of both proteins to be isolated.

Characterization of recombinant human prorenin and renin.

A cell line that secretes substantial quantities of recombinant human prorenin was prepared by transfecting Chinese hamster ovary cells with a gene encoding preprorenin. The prorenin was purified to homogeneity and was found to have a single amino terminus, reflecting cleavage after a typical 23 amino acid signal sequence. The purified inactive prorenin was not a substrate for active renin and was not capable of self-activation. Prorenin could be converted to renin by addition of exogenous protease, and deglycosylation of the prorenin did not alter the sensitivity to protease activation. The enzymatic activity of deglycosylated renin was kinetically identical to that of the native protein. Multimilligram quantities of recombinant human renin and prorenin were purified, providing suitable material for studies directed toward greater understanding of the function of these proteins and for structural studies such as x-ray diffraction for use in design of renin inhibitors.