Improvement of Phenol and Heavy Metal Removal by Streptomyces Flavabus BA4 Used for Wastewater Treatments

Abstract

With increasing of modern application of phenolic compound and their use in dettol preparation, discharge of these dangerous materials is stable for long time, too toxic and had a big risk on soil and aquatic microbes. These phenolic wastes cause severe harms to environment, human being and animals health in addition to the whole aquatic life. This study aimed to improve phenol degradation by Streptomyces flavabus BA4 previously isolated from wastewater samples.  This aerobic bacterium was belonged to filamentous bacteria with high activity to metabolize phenol carbon source, thus it can remove it from contaminated soil or wastewater. In liquid medium, growth was assayed as mg dry weight while residual phenol concentration was assayed using a colorimetric method. In minimal broth medium, Streptomyces flavabus BA4 was grown and the effects of different concentrations glucose, temperature, pH value and incubation period on phenol degradation were determined It was clear that addition of 1 g/l peptone enhanced both growth and phenol degradation was detected.  Addition of the electron donor, glucose enhanced growth but decreased phenol degradation at low concentrations (0.0-1.2 g/l). Maximum growth and phenol degradation were recorded at 30◦C in medium with pH 6.5-7 after 7 day of growth. Moreover, this isolate showed resistance to some heavy metal determined specially chromium up to 300 mg/l. Increasing heavy metal concentration decreased growth and dehydrogenates activity.  The removal rates of phenol and some heavy metals per mg dry weight of the selected bacterium were calculated for wastewater sample and were ranged from 97% for chromium to 6% for copper. In conclusion, Streptomyces flavabus BA4  is a promising  phenol degraded bacterium and adjusting some physical and biochemical factors enhancing both growth and removal process. The previous Streptomyces isolate can be used as a promising treatment for removal of phenol and some heavy metals, especially chromium which is a very toxic metal in wastewater.