Gold biosorption by exopolysaccharide producing cyanobacteria and purple nonsulphur bacteria.

AIMS: This study was aimed at investigating the possible exploitation of phototrophic micro-organisms for the removal and the recovery of Au from Au-containing wastewaters deriving from a plating industry. METHODS AND RESULTS: A screening among ten phototrophic micro-organisms was carried out with pure solutions of Au to select the best strain in terms of metal uptake and selectivity. The direct use of the selected micro-organism on the Au-containing industrial wastewater was then carried out with the aim of assessing the potential of its use for the removal and the recovery of the precious metal from industrial wastewaters. CONCLUSIONS: This study showed the good potential of some exopolysaccharide-producing cyanobacteria as biosorbents for the recovery of Au from wastewaters of plating industries but also pointed out the need to design an efficient technology for the recovery of the metal from the biomass. SIGNIFICANCE AND IMPACT OF THE STUDY: The selection of good biosorbents for the recovery of gold from industrial wastewaters may open new perspectives to a green biotechnology so far considered too expensive for the mere treatment of wastewaters containing low valuable metals.

Selectivity in the heavy metal removal by exopolysaccharide-producing cyanobacteria.

AIMS: The aim of this study was to assess the selective removal of Cu(II), Cr(III) and Ni(II) by strains of exopolysaccharide (EPS)-producing cyanobacteria, and to investigate the interaction of sorption in solutions with multiple-metals. METHODS AND RESULTS: Nine EPS-producing cyanobacteria were tested for their ability to remove Cr, Cu and Ni in both single- and multiple-metal solutions. In the single-metal solutions, some of the strains showed very high values of metal uptake, however, only two of them showed the capability to selectively remove one or two of the metals present in the multiple-metal solutions. In multi-metal systems, the binding process was either noninteractive, synergistic or competitive between metal ions for different strains of cyanobacteria. CONCLUSIONS: Cyanothece 16Som 2 showed significantly greater sorptive capacity for Cu (1.5-20x) and Cr (2-50x) than all other strains tested. The Nostoc PCC 7936 strain showed high specific and almost exclusive selectivity towards Cu, which suggests its use aimed at recovering this metal from multiple-metal solutions. SIGNIFICANCE AND IMPACT OF THE STUDY: To find out microbial sorbents with good metal selectivity may be very useful for building up processes aimed to recover valuable metals from industrial wastewaters.

[Diltiazem and modulation of platelet aggregation]. / Diltiazem e modulazione dell'aggregazione piastrinica.

The calcium antagonists including Diltiazem have been proved to inhibit platelet aggregation caused by ADP. In order to demonstrate the anti-aggregant properties of Diltiazem, a study was conducted on the aggregation curves in blood samples from 20 healthy subjects before and after a week's treatment with 240 mg oral Diltiazem per diem. The experiment confirmed the anti-aggregant properties of Diltiazem which is therefore useful in the treatment of cardiovascular disease given its capacity to dilate the coronary arteries and inhibit platelet aggregation.