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Global sustainable development has intensified the demand for switching to a renewable economy with a reduced carbon footprint. Here, we report a hybrid system, coupling a chemical process for CO2 reduction with hydrogen, and a biological process for polyhydroxybutyrate (PHB) synthesis, capable of converting CO2 into bioplastics with a theoretical carbon yield of 100%. The synthetic pathway from CO2 to PHB was modularly optimized by improving the catalytic efficiency of key enzymes, avoiding the kinetic trap of metabolic flux and optimizing the whole catalytic processes, resulting in 5.96 g/L PHB with a productivity of 1.19 g L− 1h− 1 and a molar CO2 utilization efficiency of 71.8%. These results represent a promising closed-loop production process from CO2 to biodegradable plastics.

The interactions between 2,4-dichlorophenol (2,4-DCP) and myoglobin immobilized by agarose hydrogel on the surface of a glassy carbon electrode were explored by cyclic voltammetry. 2,4-DCP coordinating with the heme of myoglobin induces a negative shift in the formal potential of myoglobin without occurrence of a catalytic reaction in anaerobic solution. However, the immobilized myoglobin functioned as cytochrome P450 under the catalytic pathways of C-hydroxylation of 2,4-DCP in an air-saturated solution. The plot of current against 2,4-DCP concentration shows a linear relationship in the range of 12.5–208 μM. The limit of detection is calculated to be 2.06 μM. UV spectra confirm that 2,4-DCP interacts with the amino-acid residues of myoglobin as well as Mb-heme. This type of study can provide important insights into the mechanisms involved in the interaction of hemoproteins with chlorophenols. The methods possess potential applications in biotechnology and biosensors.

A poly(brilliant cresyl blue) (PBCB) functionalized single walled-carbon nanotube (SWCNT) modified glassy carbon electrode (PBCB/SWCNT/GCE) is fabricated by electropolymerization. The electrocatalytic activity of the PBCB/SWCNT/GCE towards the reduction of hydrogen peroxide is then investigated. The electrode shows high sensitivity [4.1 nA (μM) −1] to the electrocatalytic reduction of H2O2 at an applied potential of −0.30 V (vs. SCE). Important practical advantages such as a fast response time (within 5 s), a low detection limit (0.12 μM), wide linear dynamic range (4.9 × 10−7 to 2.3 × 10−4 M, R2 = 0.994) and stability (remains ∼93% of its original activity after 30 days) are achieved with the PBCB/SWCNT/GCE. Further, the presence of probable interferences such as glucose, ascorbic acid, dopamine and uric acid does not interfere during the detection of H2O2. The application of the sensor to determine H2O2 in tap water with recovery values of 96% to 102% shows the sensor is suitable for routine analysis.