Improvement surfactin production by substitution of promoters in Bacillus subtilis TD7

Surfactin is one of the most representative biosurfactants and exhibits excellent surface activity plus other biological effects. It has potential applications in microbial enhanced oil recovery, environmental bioremediation, agricultural bio-control, pharmacy, cosmetics and food industries. The low yield of the surfactant from wild strains is a key restriction for industrial applications. The construction of genetically engineered bacteria by promoter substitution is an effective method to enhance surfactin production, as the promoter is a key element in gene expression. This study focuses on constructing strains with efficient surfactin production by replacing the native srfA promoter by strong promoters. In this study, two different promoter patterns with different homology arm positions were used for srfA promoter substitution. The most efficient installation way was identified as the sequence between the transcriptions start site and ribosome binding site of srfA. Moreover, eight endogenous strong auto-inducible phase-dependent promoters were chosen to substitute the native promoter of srfA using an effective substitution by the CRISPR-Cas9 system. As a result, high surfactin yielding strains with potential application in industry were constructed. According to the results, three constructed strains with promoters P43, PspoVG, and PyvyD showed increased yields of 3.5, 2.8, and 2.3 times over the wild stain B. subtilis TD7.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment. Methods We have designed and evaluated a bacterial biosensor expressing a luciferase reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans) containing the CH34 and pI258 plasmids of Staphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr biosensor and pGL3-luc/cad biosensor, that were based on the expression of luc+ and under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans. Results We found that the pGL3-luc/pbr biosensor may be used to measure lead concentrations between 1–100 μM in the presence of other metals, including zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal. The pGL3-luc/cad biosensor could detect lead concentrations between 10 nM to 10 μM. Conclusions This biosensor was found to be specific for measuring lead ions in both environmental and biological samples.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background: A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment.Methods: We have designed and evaluated a bacterial biosensor expressing a luciferase-reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans ) containing the CH34 and pI258 plasmids of Staphylococcus aureus , respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr -biosensor and pGL3-luc/cad -biosensor, that were based on the expression of luc+ under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans.Results: We found that the pGL3-luc/pbr -biosensor may be used to measure lead concentrations between 1-100 μM in the presence of other metals, including: zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal gene expression of the reporter . The pGL3-luc/cad -biosensor could detect lead concentrations between 10 nM to 10 μM.Conclusions: This biosensor was found to be a specific for measuring lead ions in both environmental and biological samples.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background: A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment. Methods: We have designed and evaluated a bacterial biosensor expressing a luciferase-reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans) containing the CH34 and pI258 plasmids of Staphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr-biosensor and pGL3-luc/cad-biosensor, that were based on the expression of luc+ and under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans. Results: We found that the pGL3-luc/pbr-biosensor may be used to measure lead concentrations between 1-100 μM in the presence of other metals, including: zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal. The pGL3-luc/cad-biosensor could detect lead concentrations between 10 nM to 10 μM. Conclusions: This biosensor was found to be a specific for measuring lead ions in both environmental and biological samples.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background: A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment.Methods: We have designed and evaluated a bacterial biosensor expressing a luciferase-reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans ) containing the CH34 and pI258 plasmids of Staphylococcus aureus , respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr -biosensor and pGL3-luc/cad -biosensor, that were based on the expression of luc+ under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans.Results: We found that the pGL3-luc/pbr -biosensor may be used to measure lead concentrations between 1-100 μM in the presence of other metals, including: zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal gene expression of the reporter. The pGL3-luc/cad -biosensor could detect lead concentrations between 10 nM to 10 μM.Conclusions: This biosensor was found to be a specific for measuring lead ions in both environmental and biological samples.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background: A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment. Methods: We have designed and evaluated a bacterial biosensor expressing a luciferase-reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans) containing the CH34 and pI258 plasmids of Staphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr-biosensor and pGL3-luc/cad-biosensor, that were based on the expression of luc+ under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans. Results: We found that the pGL3-luc/pbr-biosensor may be used to measure lead concentrations between 1-100 μM in the presence of other metals, including: zinc, cadmium, tin and nickel. The latter metals did not result in any significant signal. The pGL3-luc/cad-biosensor could detect lead concentrations between 10 nM to 10 μM. Conclusions: This biosensor was found to be a specific for measuring lead ions in both environmental and biological samples.

Construction of a sensitive and specific lead biosensor using a genetically engineered bacterial system with a luciferase gene reporter controlled by pbr and cadA promoters

Background: A bacterial biosensor refers to genetically engineered bacteria that produce an assessable signal in the presence of a physical or chemical agent in the environment. Methods: We have designed and evaluated a bacterial biosensor expressing a luciferase-reporter gene controlled by pbr and cadA promoters in Cupriavidus metallidurans (previously termed Ralstonia metallidurans) containing the CH34 and pI258 plasmids of Staphylococcus aureus, respectively, and that can be used for the detection of heavy metals. In the present study, we have produced and evaluated biosensor plasmids designated pGL3-luc/pbr-biosensor and pGL3-luc/cad-biosensor, that were based on the expression of luc+ under the control of the cad promoter and the cadC gene of S. aureus plasmid pI258 and pbr promoter and pbrR gene from plasmid pMOL30 of Cupriavidus metallidurans. Results: We found that the biodegradable pGL3-luc/pbr-biosensor could be used to measure lead concentrations between 1-100 μM in the presence of other metals, including: zinc, cadmium, tin and nickel. The latter metals did not result in any significant gene expression of the reporter. The pGL3-luc/cad-biosensor was able to detect lead concentrations between 10 nM to 10 μM. Conclusions: This biosensor was found to be a specific for measuring lead ions in both environmental and biological samples.