Textile industrial effluents deficient in carbon content and biodegradation without any extra carbon source is very difficult achieve. Therefore, different co-substrates such as sucrose, glucose, maltose, starch, dextrin, fruc- tose, manitole and lactose (0.5 g/l), were supplemented in the medium and decolorization of all the two dyes (acid orange 7 & direct blue 75) was studied individually by Com. acidovorns-TN1 and Bur. cepace-TN5. Results presented graphically in Figures 17 and 18 revealed that the decolorization of acid orange 7 & direct blue 75 was clearly dependent on the presence of a carbon source. Results recorded for the decolorization of acid orange 7 by Com. acidovorns-TN1 showed that the best decolori- zation percentage was found to in presence of starch as the carbon source, followed by fructose then maltose. Dextrin and manitole recorded the lowest decolorization percentage. The highest protein content was achieved with glucose and fructose. The lowest protein content was recorded by adding manitole as the carbon source, which is the same as in the decolorization process. Deco- lorization of acid orange 7 by Bur. cepace-TN5 showed