In our study, a polytetrafluoroethylene (PTFE) open-tubular enzyme-immobilized microreactor has been successfully prepared using dopamine polymerization and multi-layer deposition. The polydopamine layer was utilized as a primer layer in the microchannel to provide PTFE surface reactable groups, and polyethylenimine and Candida antarctica lipase B were alternatively adsorbed on the PTFE surface by the layer-by-layer method. The lipase loading kept increasing as the number of layers increased and reached a plateau at the 8th layer. The formation of multilayers and increase of enzyme loading were described and explained by the water contact angle measurement, Fourier transform infrared spectroscopy (FI-IR), and X-ray photoelectron spectroscopy, while the morphological characteristics were observed using Atomic Force Microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). Preparation of a wax ester using the microreactor had much better production efficiency (35 minutes to reach 95% yield) than that using traditional reactors (over 4 hours to complete the reaction). Very excellent stability can be achieved by the microreactor, which could be used for 144 hours with the residual activity remaining at 83% of the initial activity.

Heterogeneous catalysis ozonation technology can achieve efficient treatment of refractory organics in industrial wastewater due to its advantages including fast reaction speed, high ozone utilization rate, low catalyst loss and low cost and has a broad application prospect. The development of efficient and stable heterogeneous ozone catalytic materials is the key to promoting the application of this technology in industrial wastewater treatment. Based on this, an Mn/Al₂O₃ catalyst was successfully prepared by impregnation method using 3~5 mm γ-Al₂O₃ pellets as the carrier, and the surface morphology characteristics, elemental state and phase composition of the catalyst were investigated by SEM-EDX, XRD and XPS. The results showed that Mn was successfully loaded onto the surface of a γ-Al₂O₃ carrier. On this basis, intermittent single factor experiments were conducted to systematically investigate the effects of catalyst dosage, pH, and ozone concentration on the catalytic performance of phenol. It was found that under the optimal conditions of a catalyst dosage of 100 g (filling height of 14.2 cm), pH of 7, and ozone concentration of 4 mg/L (gas volume of 1 L/min), the removal efficiencies of 800 mL 100 mg/L of simulated phenol wastewater reached 100% after 60 min of reaction. The removal efficiencies of the catalyst still reached 95.8% within 60 min even after the fifth cycle reaction, indicating excellent reusability of the catalyst. This work provides a facile strategy for the treatment of refractory organics in industrial wastewater.

Sebacic esters have excellent lubricity, thermal stability, and biodegradability and therefore are widely used as aerospace lubricants, metal working oil, or engine oil. They are mainly produced by chemical synthesis which, however, may cause environmental pollution, its enzymatic synthesis represents a more environmentally friendly alternative. A few reports have described the synthesis of sebacic esters employing immobilised lipases, but these biocatalytic reactions were exclusively carried out in solvent-free systems and thus, could have been limited by slow reaction rates and high reaction temperatures due to poor enzyme dispersion, low substrate solubility, and high viscosity of the reaction mixture. The current study investigated the biosynthesis of dioctyl sebacate in toluene by Novozym 435, a commercial immobilised lipase. The reaction parameters were investigated using the single factor approach and an orthogonal array design. The optimal conditions obtained were as follows: 10 mL toluene, sebacic acid,1 mmol (202.25 mg); molar ratio of sebacic acid to 1-octanol, 1:3; Novozym 435, 0.03 g; 4 Å molecular sieves, 1.5 g; reaction temperature, 40 °C; reaction time, 30 h. A dioctyl sebacate conversion rate of 93% was achieved under these optimal conditions. In particular, the addition of molecular sieves to the reaction mixture markedly improved the product yield. The reaction temperature was low enough to make the operation easy and energy-efficient and therefore, well suited for large-scale production.

Phenoxazinone synthase (PHS) is a laccase-like multicopper oxidase originating from Streptomyces with great industrial application potential. In this paper, we prepared the PHS nanogel retaining 82 % of its initial activity by aqueous in situ polymerization at pH 9.3. The average diameter of the PHS nanogel was 50.8 nm based on dynamic light scattering (DLS) analysis. Fluorescence analysis indicated the impressive preservation of the enzyme molecular structure upon modification. The PHS nanogel exhibited the most activity at pH 4.0–4.5 and 50 °C while the corresponding values were pH 4.5 and 40 °C for the native PHS. The K _m and V _max of the PHS nanogel were found to be 0.052 mM and 0.018 mM/min, whereas those of the native PHS were 0.077 mM and 0.021 mM/min, respectively. In addition, the PHS nanogel possessed higher thermal and storage stability and solvent tolerance compared with the native one. The half-life of the PHS nanogel was 1.71 h and multiplied around ninefold compared to 0.19 h for the native one. In summary, the PHS nanogel could be a promising biocatalyst in industry.