chromosomally based luminescent bioassay for mercury detection in red soil of China

• Published in: Applied microbiology and biotechnology Vol. 87; no. 3; pp. 981 - 989
• Main Authors: Wei, He, Cheng, Han, Ting, Mao, Wen-Hui, Zhong, Xian-Gui, Lin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.07.2010; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Bioassays; Bioavailability; Biological and medical sciences; Biological Assay - methods; Biomedical and Life Sciences; Biosensor; Biosensors; Biotechnological Products and Process Engineering; Biotechnology; China; Chromosomes; Chromosomes, Bacterial - genetics; Cobalt; E coli; EGFP; Environmental monitoring; Fundamental and applied biological sciences. Psychology; Gene Expression; Genes; Genes, Reporter; Genetic engineering; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Laboratories; Life Sciences; Liquid chromatography; Luminescent Proteins - genetics; Luminescent Proteins - metabolism; Mercury; Mercury - analysis; Methods. Procedures. Technologies; Microbial Genetics and Genomics; Microbiology; Organic matter; Plasmids; Pollutants; Promoter Regions, Genetic; Pseudomonas putida; Pseudomonas putida - genetics; Pseudomonas putida - metabolism; Red soil; Soil - analysis; Soil contamination; Soil Pollutants - analysis; Soil sciences; Soils; Studies; Various methods and equipments; China; EGFP; Mercury; Red soil; Biosensor; Soils; Bioassay; Luminescence; Detection
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-010-2548-9

A luminescent reporter gene system was constructed by fusing the mercury-inducible promoter, P merT , and its regulatory gene, merR, with a promoterless reporter gene EGFP. A stable and nonantibiotic whole-cell reporter (BMB-ME) was created by introducing the system cassette into the chromosome of Pseudomonas putida strain and then applied it for mercury detection in the red soil of China. Spiked with 10 and 100 μg g⁻¹ Hg²⁺ and after 15 and 30 days incubation, soil samples were extracted and evaluated water soluble, bioavailable, organic matter bound, and residual fractions of mercury by both BMB-ME and chemical way. The expression of EGFP was confirmed in soil extraction, and fluorescence intensity was quantified by luminescence spectrometer. The sensor strain BMB-ME appeared to have a detection range similar to that of reversed-phase high-performance liquid chromatography method. The optimal temperature for EGFP expression was 35°C and the lowest detectable concentration of Hg²⁺ 200 nM. Cu²⁺, Fe²⁺, Mn²⁺, Sn²⁺, Zn²⁺, Co²⁺, Ag⁺, Ba²⁺, Mg²⁺, and Pb²⁺ ions at nanomolar level did not interfere with the measurement. These results showed that the BMB-ME constitute an adaptable system for easy sensing of small amounts of mercury in the red soil of China.