Rapid detection of heavy metal-induced toxicity in water using a fed-batch sulfur-oxidizing bacteria (SOB) bioreactor

• Published in: Journal of microbiological methods 2019-06, Vol.161, p.35-42
• Main Authors: Eom, Heonseop, Hwang, Ji-hoon, Hassan, Sedky H.A., Joo, Jin Ho, Hur, Jang Hyun, Chon, Kangmin, Jeon, Byong-Hun, Song, Young-Chae, Chae, Kyu-Jung, Oh, Sang-Eun
• Format: Article
• Language: English
• Subjects: Electrical conductivity; Fed-batch bioreactor; Heavy metals; Sulfur-oxidizing bacteria; Toxicity test
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/j.mimet.2019.04.007

A fed-batch bioreactor based on sulfur-oxidizing bacteria (SOB) was tested for rapid detection of heavy metal-induced toxicity in water. For this evaluation, SOB were exposed to water contaminated by selenium, mercury, hexavalent chromium, arsenic, cyanide, cadmium, and lead for 2 h and their inhibition rates were analyzed based on changes in electrical conductivity (EC). The results demonstrate that SOB were highly inhibited by selenium, mercury, hexavalent chromium, and arsenic but not by cyanide, cadmium, and lead. The 2 h half maximum effective concentrations (EC50) of SOB for selenium, mercury, hexavalent chromium, and arsenic were estimated to be 0.33, 0.89, 1.18, and 0.24 mg/L, respectively, which are comparable or lower than earlier reports in the literature. However, the EC50 or EC20 values of SOB for cyanide, cadmium, and lead were notably higher compared to findings from previous toxicity tests that employed other microorganisms. The findings from the current study suggest that the fed-batch SOB bioreactor is suitable for rapid detection of toxicity induced by selenium, mercury, hexavalent chromium, and arsenic in water. •Microbial activity of SOB is measurable by monitoring electrical conductivity.•SOB bioassay is highly sensitive to toxicity of Se2−, Hg2+, Cr6+, and As3+ in water.•SOB bioassay is not sensitive to toxicity of CN−, Cd2+, and Pb2+ in water.