Microbial Population and Identification of Phthalate Ester-Utilizing Microorganisms in Activated Sludge Inoculated with Microorganisms

Abstract

In the population in each of activated sludges, the ratio of all Nocardia erythropolis cells to total cells increased from 5.6% immediately after inoculation to 16.1 % 26 days later in the inoculated sludge in which DEHP was fed, and from 6.1 % to 13.9% 22 days later in the inoculated sludge in which DBP was fed. In particular, strains of Nocardia erythropolis isolated from the inoculated activated sludges, which were morphologically, biochemically and immunologically identical with Nocardia erythropolis S–1 inoculated, were predominant in the total phthalate ester-utilizing microorganisms. The species which shared the highest ratio to the population in each of activated sludges were members of the genus Pseudomonas. They were unable to grow on phthalate esters but able to utilize the intermediates such as phthalate. These Pseudomonas species comprised about 30% of total cells. Phthalate ester-utilizing microorganisms isolated from the inoculated activated sludge were Nocardia erythropolis, Nocardia calca...