Halophilic starch degrading bacteria isolated from Sambhar Lake, India, as potential anode catalyst in microbial fuel cell: A promising process for saline water treatment

In this study, Microbial Fuel Cell (MFC) capable of treating saline starch water was developed. Sodium chloride (NaCl) concentrations ranging from 500 mM to 3000 mM were tested at the anode. Nitrate was used as an electron acceptor at the biocathode. The halophilic bacteria were isolated from Sambhar Lake, India. Results indicated successful removal of starch (1.83 kg/m3-d) and nitrate (0.13 kg/m3-d NO3−-N) with concomitant power output of 207.05 mW/m2 at 1000 mM NaCl concentration. An increase in power density from 71.06 mW/m2 to 207.05 mW/m2 (2.92 folds) was observed when NaCl concentration was increased from 500 mM to 1000 mM. A decline in power density was observed when the salt concentrations >1000 mM were used. Concentration of 3000 mM supported power output as well as the highest starch degradation (3.2 kg/m3-d) and amylase activity of 2.26 IU/ml. The halophilic exoelectrogens were isolated and identified. The present study demonstrates the utility of MFC for degrading starch in saline water.