Abstract
Arsenic (As) contamination in an ecosystem has been a serious threat for the ecosystem as well as human health. Thus, the present study was established an eco-friendly remediation of As by using As resistant Rhodobacter sp. Accordingly, the growth of Rhodobacter sp. in As stress environment was assessed. Expectedly, enhanced growth order of the Rhodobacter sp., under As stress was found to be control >50 > 100 > 200 > 300 > 400 > 500 mg/L of As. In addition, the present study explored the influence of various light sources (Yellow, light blue, red, green and white) on growth and As removal mechanisms of Rhodobacter sp. The growth profile of the bacteria indicated that the light blue source showed an enhanced growth at 72 h of incubation. Based on optimization experiments, an increased As removal percentage rate was found to be at 87.5% at pH 7.0, 3% of glucose, 1% of citrate supplemented in the medium. The As resistant genetic pattern for arsenic transformation, the genes arsenate reductase (arsC), arsenite oxidase (aio) was investigated. To study the transcript level expression of arsC and aio genes were performed after exposure to different concentrations of As (50, 100, 150, and 200 mg/L) at different time intervals (24, 48, 72 and 96 h). The results showed that both arsC and aio were up regulated from 24 to 72 h and the down regulation was observed at 96 h. The obtained results indicated that the Rhodobacter sp., possess significant AS tolerance and removal potential would make it is a noteworthy candidate for future As remediation practices.