Bioreduction of chromate by immobilized cells of Halomonas sp

In this work, the bioreduction of Cr(VI) by immobilized cells of Halomonas sp was reported. Ca alginate, acryl amide and agar were tested as the matrices for immobilization. Ca alginate was found to be the suitable matrix among the different matrices studied. Of the various dosages of inoculum studied 2 g/L was found to be the optimum. Glucose at 1 g/L was completely utilized by the immobilized Halomonas sp even in the presence of Cr(VI) at 40 mg/L. The optimum pH for the bioreduction of Cr(VI) by immobilized Halomonas sp was found to be pH 6. The mechanical strength of the beads plays an essential role in the bioreduction process. Halomonas sp entrapped in a alginate matrix reported a maximum of 98.9 % of reduction for an initial Cr(VI) concentration of 10 mg/L. The alginate beads can be reused for 3 times with slight drop in the percentage reduction. The presence of other metals decreased the bioreduction percentage.