{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,24]],"date-time":"2026-02-24T07:59:56Z","timestamp":1771919996660,"version":"3.50.1"},"reference-count":47,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T00:00:00Z","timestamp":1771632000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Science and Technology Council","award":["NSTC 112-2313-B-157-001-MY3"],"award-info":[{"award-number":["NSTC 112-2313-B-157-001-MY3"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biosensors"],"abstract":"<jats:p>Hexavalent chromium (Cr(VI)) is a high-priority environmental pollutant due to its strong oxidizing properties, which cause DNA damage and other severe health effects. Conventional detection methods are often costly and lack real-time monitoring capabilities, creating a strong demand for cost-effective, real-time biosensors that meet industrial requirements. In this study, we developed a novel biosensor for continuous Cr(VI) monitoring using a single-chamber microbial fuel cell (MFC). The biological element is an engineered Escherichia coli strain (ChrA-ChrB-E. coli), constructed by introducing Cr(VI)-resistant (ChrA) and Cr(VI)-reducing (ChrB) genes. The presence of Cr(VI) affects bacterial metabolism and electron transfer within the MFC, generating a measurable signal proportional to the contaminant\u2019s concentration. The biosensor demonstrated robust performance and characteristics. The recombinant strain retained functional activity after 450 days of storage at \u221220 \u00b0C. The system exhibited high sensitivity and excellent linearity (R2 \u2265 0.999) across a broad Cr(VI) concentration range of 0.015\u2013200 mg\/L. During continuous monitoring of chrome tanning and electroplating wastewater, measurements deviated by less than 2.33% from the standard diphenylcarbazide (DPC) method; electroplating deviation was further reduced to \u22120.69% with EDTA pretreatment. In fishery water, the deviation was higher (\u22127.12%) due to dissolved oxygen (DO) interference but was reduced to \u22120.75% after mechanical stirring to remove DO. The biofilm bacterial community remained highly stable over six months in both wastewater types, with the inoculated ChrA-ChrB-E. coli strain maintaining dominance (&gt;99.6%). These results substantiate the feasibility of using this biosensor for continuous, online, real-time detection of Cr(VI) in actual wastewater environments.<\/jats:p>","DOI":"10.3390\/bios16020130","type":"journal-article","created":{"date-parts":[[2026,2,23]],"date-time":"2026-02-23T08:58:21Z","timestamp":1771837101000},"page":"130","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Practical Considerations for Continuous Monitoring of Hexavalent Chromium in Wastewater Using a Microbial Fuel Cell Biosensor: Biosensor Fabrication, Sample Pretreatment, and Bacterial Community Analysis"],"prefix":"10.3390","volume":"16","author":[{"given":"Guey-Horng","family":"Wang","sequence":"first","affiliation":[{"name":"Research Center of Natural Cosmeceuticals Engineering, Xiamen Medical College, Xiamen 361008, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chiu-Yu","family":"Cheng","sequence":"additional","affiliation":[{"name":"Department of Biological Science and Technology, China University of Science and Technology, Taipei 115, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0425-5444","authenticated-orcid":false,"given":"Ying-Chien","family":"Chung","sequence":"additional","affiliation":[{"name":"Department of Biological Science and Technology, China University of Science and Technology, Taipei 115, Taiwan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,2,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"484","DOI":"10.1007\/s40572-024-00460-9","article-title":"Carcinogenic mechanisms of hexavalent chromium: From DNA breaks to chromosome instability and neoplastic transformation","volume":"11","author":"Meaza","year":"2024","journal-title":"Curr. 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