The separation of oil from an oil-water-bacteria mixture using a hydrophobic tubular membrane

The separation of oil from oil-water-bacteria mixtures is of great importance for the development of whole-cell biocatalytic processes in the presence of organic solvents. We found that a hydrophobic polytetrafluroethylene (PTFE) tubular membrane was effective in separating n-tetradecane, a model oil from 50% (v/v) n-tetradecane in water. When the PTFE tubular membrane was prewetted by n-tetradecane, it was also effective in separating n-tetradecane from 50% (v/v) n-tetradecane in an aqueous medium containing Rhodococcus erythropolis KA2-5-1 as a whole-cell biocatalyst for biodesulfurization. Microscopic observation confirmed that the recovered oil was essentially free of bacterial cells. Though the flux rate fell off with time of filtration, repeated backwashing of the membrane enhanced the flux performance approximately two-fold.