Effect of pH variation on the activity of green algae (Chlorella Vulgaris) and bacteria (Bacillus subtilis) in remediation of toxic dye (Congo red)

Abstract

The present study used two species of microorganism, algae (Chlorella Vulgaris) and bacteria (Bacillus subtilis), in the removal of toxic industrial dye(Congo red) and deal with the effect of pH variation on the activity of these organisms to remediation and reduces of dye in vitro. Algae (C.vulgaris) also bacteria(B.subtilis) isolated from habitats and cultured under controlled laboratory conditions and using different concentration of dye (50, 150 and 250 mg/l) used in different pH (4, 7 and 9) during different period times (3, 7, 9, 11 and 13 days) to algae and 7 days to bacteria to testing the ability of bioremediation. The results showed that the best pH for removal by Chlorella Vulgaris was (7) for a period of (13 days) at concentration (150)mg/l and with the complete removal (75%) and Bacillus subtilis best pH(7) complete removal(98%) at concentration (50)mg/l. The efficiency of the Chlorella Vulgaris and Bacillus subtilis in the removal of pollutants increased with the high value of many environmental factors such as pH.