Extracellular polymer produced in the presence of copper minerals

A qualitative and semiquantitative assay was applied to estimate production of peripheral exopolymers by strains of bacteria isolated from flotation wastes during growth on copper sulphides and copper minerals wastes at neutral pH. Exopolymer production, expressed as percentage of Alcian Blue adsorption per mu g of cell protein, was the lowest on a complete organic medium and the highest on a nutrient-limited mineral medium. The exopolymer was highly resistant to acid hydrolysis and contained hydrocarbons, saturated and unsaturated fatty acids, aromatic acids and aromatic acid esters, which are well known as artificial surfactants and plasticizers. Carbohydrates appeared incidentally and in trace amount only. Chemical components of the exopolymer or chemically similar compounds also were found in black shale particles in the flotation wastes.