摘要：Nowadays, drug, pulping, textile and other industries are developed in most of the countries and their nonsave sewages makes many problems for environment. One of the most important dangerous sewage ispigmented sewage, which has complex structures such as azo compounds. In Iran one of the main sourcesof pigmented sewage is textile manufacturing. Hence, in order to remove colour of this sewage, the presentstudy was conducted to evaluate potential of some bacteria for dye decolourising. To perform this investigation30 samples from soil and 10 from sewage were collected. All bacteria with potential of decolorization wereisolated and identified using biochemical tests. Out of seven different isolated bacteria three were Grampositive and four were Gram negative. Optimization of decolorization for all bacteria was carried out insecond step with respect to evaluation of bacterial activity at different temperatures (25-45°C), pHs (5-9)and dye concentrations (0.01-0.04g/L). The results obtained indicated that the best temperature for all bacteriatested was 35°C, pH 8.0, and dye concentration 0.02 g/L. Therefore, decolorization of pigmented sewage forelimination of dangerous compounds could be possible using bacteria.
