<p dir="ltr"><b>A Calcium- and Magnesium-Tolerant Enterobacter sp. MTT Respiratory Inhibition Assay for Rapid Screening of Mercury and Silver in Industrial River Water</b></p>

This study developed a whole-cell respiratory inhibition assay based on the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by a locally isolated bacterium. Enterobacter sp. strain DRY13, retained respiratory activity in the presence of Ca2+ and Mg2+ yet responded strongly to toxic metals. supported tentative placement within Enterobacter.

Among 13 metals tested, Ag+ and Hg2+ produced greater than 50% inhibition at 10 mg L−1. One-phase exponential models yielded IC50 values of 0.139 mg L−1 for Ag+ (95% CI, 0.115–0.173 mg L−1) and 0.144 mg L−1 for Hg2+ (95% CI, 0.106–0.221 mg L−1), with R2 values of 0.9842 and 0.999, respectively. The reported limits of detection were 0.0033 mg L−1 for Ag+ and 0.0216 mg L−1 for Hg2+; corresponding limits of quantification were 0.0294 and 0.0386 mg L−1.