Growth and survival of protozoa isolated from a tannery effluent

Industrial effluent from a tannery was used for the growth of algae in a medium containing various inorganic salts. Growth of algal cells became visible after 7 d. Two species of protozoa were observed to proliferate in the algal culture containing no organic supplement in the medium. The culture was kept bacteria-free by the use of antibiotics and was perpetuated for at least 150 d with no decline in the protozoan population. Efficient growth of protozoa in a culture of algae elucidated new modes of nutrition in protozoa. Cr(VI) was added to the medium to check the resistance of algae and protozoa against this heavy metal. Protozoa showed different degrees of resistance. The results indicate the importance of algae and protozoa in the process of bioremediation.