Polyhydroxybutyrate production by recombinant Escherichia coli based on genes related to synthesis pathway of PHB from Massilia sp. UMI-21.

Background: Polyhydroxybutyrate (PHB) is currently the most common polymer produced by natural bacteria and alternative to conventional petrochemical-based plastics due to its similar material properties and biodegradability. Massilia sp. UMI-21, a newly found bacterium, could produce PHB from starch, maltotriose, or maltose, etc.

Enhancing Production of Medium-Chain-Length Polyhydroxyalkanoates from sp. SG4502 by Enhancer Insertion.

sp. SG4502 screened from biodiesel fuel by-products can synthesize medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using glycerol as a substrate. It contains a typical PHA class II synthase gene cluster.

A New Fluorescent Probe Tool: ERNathG.

β-d-Glucuronidase (GUS) plays a pivotal role in both clinical treatment assessment and environmental monitoring. Existing tools for GUS detection suffer from (1) poor continuity due to a gap between the optimal pH of the probes and the enzyme and (2) diffusion from the detection site due to lack of an anchoring structure. Here we report a novel GUS pH-matching and endoplasmic reticulum-anchoring strategy for GUS recognition.

A novel, environmentally friendly dual-signal water toxicity biosensor developed through the continuous release of Fe.

In this work, a novel, environmentally friendly and simple electrochemical/colorimetric water toxicity biosensor was rationally developed by the continuous release of Fe in a medium. The bioluminescent bacterium Vibrio Fischeri (V. fischeri) was used for the first time as a model bacterium to assess water toxicity for a mediated electrochemical biosensor.

Application study of RGB color extraction in water toxicity detection.

In this work, a colorimetric biosensor based on the rapid color change of Escherichia coli DH 5α (E. coli) and p-benzoquinone (BQ) was introduced to evaluate water toxicity. Here, dark brown quinhydroquinone (QHQ) was obtained from the reaction between E.

Study on simplified strategies for procedure of rapid detection of water toxicity.

In this work, a simplified procedure of detection of water toxicity based on Pt ultramicroelectrode (UME) and mixed microorganism cultured without sterilization was the first proposed. A stable Pt UME was successfully prepared with a special glass tube as insulation and support material, which was used as working electrode in the biosensor. The Pt UME exhibits the typical cyclic voltammogram (CV) of Pt UME with sigmoid shape and possesses good stability, enlarged current response and tunable dimension.

Colorimetric and Electrochemical Dual-Signal Method for Water Toxicity Detection Based on and -Benzoquinone.

The development of simple and rapid toxicity detection methods has important practical significance. In this work, a dual-signal method with colorimetric and electrochemical properties for water toxicity detection was proposed for the first time based on a rapid color reaction between () and -benzoquinone (BQ). Here, was used as a biocatalyst and BQ was used as a mediator.

FeS nanoparticles decorated carbonized Luffa cylindrica as biofilm substrates for fabricating high performance biosensors.

A high-performance microbial biosensor was fabricated with a reasonably designed biofilm substrate, where the aerogel of carbonized Luffa cylindrica (LC) was used as the scaffold for loading biofilm and FeS nanoparticles (FeSNPs) were employed to modify this aerogel (FeSNPs/Gel). The fabricated FeSNPs/Gel exhibited a spring-like structure similar with that of the raw LC, which facilitated the linkage of the scaffold and promoted its mechanical strength, and further prolonged the service period of the as-prepared biosensor from few days to two months. Meanwhile, the introduced FeSNPs improved the microbial electron transfer of the biofilm and causing an increase in the sensor's signals from 155.

Fabrication of a Novel, Cost-Effective Double-Sided Indium Tin Oxide-Based Nanoribbon Electrode and Its Application of Acute Toxicity Detection in Water.

Microelectrode plays a crucial role in developing a rapid biosensor for detecting toxicity in water. In this study, a nanoribbon electrode (NRE) with amplified microelectrode signal was successfully prepared by electrodepositing 2-allylphenol on a double-sided indium tin oxide glass. The NRE provided a simple mean for obtaining large steady-state current response.

An unexpected discovery of 1,4-benzoquinone as a lipophilic mediator for toxicity detection in water.

Since most toxicological risk assessments are based on individual single-species tests, there is uncertainty in extrapolating these results to ecosystem assessments. Herein, we successfully developed a mediated microbial electrochemical biosensor with mixed microorganisms for toxicity detection by microelectrode array (MEA). In order to fully mobilize all the mixed microorganisms to participate in electron transfer to amplify the current signal, 1,4-benzoquinone (BQ) was used as the lipophilic mediator to mediate the intracellular metabolic activities.

How to Identify the "LIVE/DEAD" States of Microbes Related to Biosensing.

In this work, we fabricated a microbial biosensor with long-term stability, which relied on microbial activity. Activity of the microbe was commonly estimated by LIVE/DEAD assay and the propidium iodide (PI)-stained one was judged as dead. Herein, we proposed the utilization of a physiological state of microbes, which was neither live nor dead but between them.

A respiration substrate-less isolation method for acute toxicity assessment.

Respiration substrate (RS)-less isolation method was developed for enhancing the sensitivity of acute toxicity assessment of heavy metal ions. RS was removed from the first step of previous isolation method, which was an effective strategy for improving acute toxicity assessment. 50% inhibiting concentration (IC) values of Cu, Cd, Zn, Hg and Ni were 0.

Self-Rechargeable-Battery-Driven Device for Simultaneous Electrochromic Windows, ROS Biosensing, and Energy Storage.

A self-powered electrochromic device (ECD) powered by a self-rechargeable battery is easily fabricated to achieve electrochromic window design, quantitative reactive oxygen species (ROS) sensing, and energy storage. The special design of the battery was composed of Prussian blue (PB) and magnesium metal as the cathode and anode, respectively, which exhibits fast self-charging and high power-density output for continuous and stable energy supply. Benefitting from the fast electrochromic response of PB, it was not only used for structuring self-rechargeable batteries but also used as an electrochromic display for highly sensitive self-powered ROS sensing and visual analysis.

Preparation, performance, and application of a stable, sensitive and cost-effective microelectrode array.

The development of rapid toxicity detection technology has higher requirements for electrode. In this work, a stable, sensitive and cost-effective microelectrode array (MEA) was successfully prepared manually. The advantage of the as-prepared MEA was discussed by means of detecting toxicity of 3,5-Dichlorophenol (3,5-DCP) by contrasting with bulk electrode and single microelectrode, in which mixed microorganisms were selected as biocatalyst, and K[Fe(CN)] was adopted as electron mediator.

In situ fabrication of hollow ZnO@NC polyhedra from ZIF-8 for the determination of trace Cd(ii).

In this work, a novel electrochemical sensor for Cd(ii) detection with differential pulse anodic stripping voltammetry (DPASV) is fabricated based on hollow ZnO@nitrogen-doped carbon (H-ZnO@NC) polyhedra, which are prepared from ZIF-8 via in situ tannic acid etching and a subsequent calcination process. The as-obtained H-ZnO@NC exhibits a polyhedral morphology with a well-defined hollow structure and a uniform distribution of elements C, N, O, and Zn in the shell. The unique structure of H-ZnO@NC can provide an enlarged surface area and abundant active sites.

Small Microbial Three-Electrode Cell Based Biosensor for Online Detection of Acute Water Toxicity.

The monitoring of toxicity of water is very important to estimate the safety of drinking water and the level of water pollution. Herein, a small microbial three-electrode cell (M3C) biosensor filled with polystyrene particles was proposed for online monitoring of the acute water toxicity. The peak current of the biosensor related with the performance of the bioanode was regarded as the toxicity indicator, and thus the acute water toxicity could be determined in terms of inhibition ratio by comparing the peak current obtained with water sample to that obtained with nontoxic standard water.

New applications of genetically modified Pseudomonas aeruginosa for toxicity detection in water.

A novel mediator-free method based on genetically modified bacteria was developed for detecting water toxicity, where genetically modified Pseudomonas aeruginosa (GM P. aeruginosa) was selected as the biosensor strain and pyocyanin (PYO) produced by this strain was used as the indicator. The toxicity response of GM P.

Toxicity detection in water containing heavy metal ions with a self-powered microbial fuel cell-based biosensor.

In this work, a self-powered microbial fuel cell (MFC)-based biosensor was developed for detecting toxicity in water containing heavy metal ions. Experimental conditions containing concentration of potassium ferricyanide, load resistor and glucose concentration were optimized. Six heavy metal ions (2mg/L, Cu, Hg, Zn, Cd, Pb and Cr) were tested by this biosensor and the inhibition ratios obtained were 12.

Detecting total toxicity in water using a mediated biosensor system with flow injection.

A novel total toxicity detection method based on a mediated biosensor system with flow injection (MB-FI) was developed to rapidly and reliably detect respiration inhibitors (i.e., As2O3, KCN, salicylic acid (SA), 2,4-dintirophenol (DNP)) in water.

Biochemical oxygen demand measurement by mediator method in flow system.

Using mediator as electron acceptor for biochemical oxygen demand (BOD) measurement was developed in the last decade (BODMed). However, until now, no BOD(Med) in a flow system has been reported. This work for the first time describes a flow system of BOD(Med) method (BOD(Med)-FS) by using potassium ferricyanide as mediator and carbon fiber felt as substrate material for microbial immobilization.

Toxicity detection of sodium nitrite, borax and aluminum potassium sulfate using electrochemical method.

Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an analyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose-glutamic acid as an exogenous material.

A rapid and sensitive p-benzoquinone-mediated bioassay for determination of heavy metal toxicity in water.

Determining and monitoring toxicity of chemicals in water are very important for human health and country security. Electrochemical measurement of respiratory chain activity is a rapid and reliable screening of the toxicity towards microorganisms. Here, we report a rapid and sensitive toxicity bioassay using p-benzoquinone as the artificial electron mediator and Escherichia coli as the test organism.

Development of a simple method for biotoxicity measurement using ultramicroelectrode array under non-deaerated condition.

In this paper, a mediated method by using ferricyanide under non-deaerated condition for biotoxicity measurement was proposed. Ultramicroelectrode array (UMEA) was employed for effectively amplify the electrochemical signal from the total limiting currents to distinguish a little change in toxicity. Five species of microorganisms including two bacilli (Escherichia coli and Enterobacter cloacae), two pseudomonas (Pseudomonas fluorescens and Pseucomonas putida) and one fungus (Trichosporon cutaneum) were employed.

Cell-based biosensor for measurement of phenol and nitrophenols toxicity.

A cost-effective whole cell biosensor based on electrochemical technique to detect toxicities of phenol and nitrophenols has been developed. This method relied on the inhibition effect for respiratory chain activity of microorganism by toxicant, which was measured by chronoamperometry using mediator (ferricyanide). The current signals produced by suspended microorganisms and reoxidation of ferrocyanide were transformed to inhibiting efficiency directly, and 50% inhibiting concentration (IC(50)) was chosen as the quantitative standard of toxicity.

A sensitive, rapid and inexpensive way to assay pesticide toxicity based on electrochemical biosensor.

We reported a rapid toxicity assay method using electrochemical biosensor for pesticides, Escherichia coli (E. coli) was taken as a model microorganism for test. In this method, we adopted ferricyanide instead of natural electron acceptor O(2), and then microbial oxidation was substantially accelerated.