Abstract: A method for purifying water or a water-containing material which comprises using a single or a few bacterial strains whose growth(s) is or are enabled or promoted by the addition of one or more of S-, N- and C- compounds under a low nutritional condition. A living bacterial preparation, useful for the purification of water or water-containing material, comprising a single or a few bacterial strains whose growth(s) is or are enabled or promoted by addition of one or more of S-, N- and C- compounds under a low nutritional condition is also disclosed.

Abstract: A bacterial strain comprising a strain of Pseudomonas exhibits acceleration of growth in a logarithmic phase in a trophic culture medium when hydrocarbons are added thereto, a process for producing such a bacterial strain, and a purification process using such a bacterial strain.