Reduction of perchlorate by salt tolerant bacterial consortia

Two perchlorate-reducing bacterial consortia (PRBC) were obtained by enrichment cultures from polluted marine sediments. Non-salt-tolerant PRBC (N-PRBC) was enriched without the addition of NaCl, and salt tolerant-PRBC (ST-PRBC) was enriched with 30 g-NaCl L−1. Although the perchlorate reduction rates decreased with increasing NaCl concentration, ST-PRBC (resp., N-PRBC) could reduce perchlorate until 75 g-NaCl L−1 (resp., 30 g-NaCl L−1). The reduction yield (1.34 ± 0.05 mg-perchlorate per mg-acetate) and maximum perchlorate reduction rate (86 mg-perchlorate L−1 h−1) of ST-PRBC was higher than those (1.16 ± 0.03 mg-perchlorate per mg-acetate and 48 mg-perchlorate L−1 h−1) of N-PRBC. Kinetic analysis showed that NaCl acted as an uncompetitive inhibitor against both PRBCs. The inhibition constants were 25 and 41 mg-NaCl L−1 for N-PRBC and ST-PRBC, respectively.