Transcription profiling-guided remodeling of sulfur metabolism in synthetic bacteria for efficiently capturing heavy metals

[Display omitted] •Transcription profiling reveals the role of sulfur metabolism in heavy metal capture.•A sulfur metabolism operon is de novo synthesized for constructing synthetic cells.•The synthesized operon remodels sulfur metabolism network in large scale.•The synthesized operon remarkably enhances heavy metal-tolerating capacity.•The synthesized operon remarkably promotes heavy metal capture in synthetic cells. Heavy metal contamination is becoming a global problem threatening human health. Heavy metal removal by engineered microbes by cellular adsorption and uptake is a promising strategy for treatment of heavy metal contamination. However, this strategy is confronted with limited heavy metal-capturing elements. In this study, we performed a transcription profiling-guided strategy for construction of heavy metal-capturing synthetic bacteria. Transcription profiling of a heavy metal-tolerating Cupriavidus taiwanensis strain revealed up-regulation of sulfur metabolism-related operons (e.g., iscSAU and moaEDAB) by Pb2+ and Cd2+. A synthetic Escherichia coli strain, EcSSMO, was constructed by design of a synthetic sulfur metabolism operon (SSMO) based on iscSAU/moaEDAB. Biochemical analysis and X-ray photoelectron spectroscopy (XPS) revealed that the synthetic bacteria had remodeled sulfur metabolism and enhanced heavy metal-tolerating capacity, with higher surviving EcSSMO cells than the surviving control cells Ec0 (not containing SSMO) at 50 mg/L of Pb2+ and Cd2+ (>92 % versus 90 % of Pb2+ and Cd2+ at 5 mg/L of Pb2+ and Cd2+, and >40 % of both heavy metals even at 50 mg/L of Pb2+ and Cd2+. This study reveals emphasizes feasibility of transcription profiling-guided construction of synthetic organisms by large-scale remodeling metabolic network.