Bisphenols are important industrial materials for example for the production of plastics, but are also well known for their adverse health effects, in particular bisphenol A (BPA) is an endocrine disruptor. The widespread use of plastics has raised concerns. Therefore, the removal of bisphenols from wastewater has sparked the interest of the scientific community. This work introduces a novel hybrid technique of micro-nano bubbles assisted laccase (MNB-Lac) to degrade bisphenols in water. The feasibility of MNB-Lac using BPA as a model contaminant was evaluated by comparing with MNB, Lac, ultrasound (UL), UL-Lac, and UL-MNB-Lac. Comprehensive investigations were carried out to understand the specific influences of key process parameters including the initial pollutant concentration, temperature, air intake, pH, outlet pipe length, and Lac concentration on BPA degradation. The alkaline environment and extended length of outlet pipe could improve the degradation efficiency further. MNB-Lac exhibited 2.3–6.2 folds higher BPA degradation and less time than the other above process under the optimal parameters. The mechanism of MNB-Lac revealed that the generation of hydroxyl radical, high O₂ solubility, and high mass transfer efficiency induced by MNB play important roles on enhancing the degradation catalyzed by Lac. MNB-Lac was successfully used for treating bisphenol B, bisphenol C, and the mixture of three bisphenols with high removal efficiency. Subsequently, these degradation products were analyzed by GC–MS. MNB-Lac potentially represents an innovative technology with considerable advantages in contaminant cleanup and time efficiency for treating phenolic contaminated water. Furthermore, the findings provide new insights into the enhancement of the performance of an oxidizing enzyme by introducing MNB technology.

Laccase is a versatile multicopper oxidase that holds great promise for many biotechnological applications. For such applications, it is essential to explore good biocatalytic systems for high activity and recyclability. The feasibility of membrane enclosed enzymatic catalysis (MEEC) for enzyme recycling with laccase was evaluated. The dialysis membrane enclosed laccase catalysis (DMELC) was tested for the conversion of the non-phenolic model substrate 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS). Trametes versicolor laccase was found to be completely retained by the dialysis membrane during the process. The ABTS total conversion after DMELC reached the same values as the batch reaction of the enzyme in solution. The efficiency of DMELC conversion of ABTS under different process conditions including shaking speed, temperature, ABTS concentration and pH was investigated. The repetitive dialysis minimally affected the activity and the protein content of the enclosed laccase. DMELC retained 70.3 ± 0.8% of its initial conversion after 5 cycles. The usefulness of MEEC extends to other enzymes with the benefit of superior activity of an enzyme in solution and the recyclability which is normally only obtained with immobilized enzymes.[Figure not available: see fulltext.]

Hypericin is considered to be the most biologically active substance in the crude extract of Hypericum perforatum L. (also known as St. John's wort) and has a wide range of pharmacological effects. In this study, a high resolution high performance liquid chromatography method for determining hypericin was established by comparing different chromatographic conditions. Xylanase-assisted extraction and microwave-assisted extraction can improve the extraction yield of hypericin significantly. And the coupling strategy between two methods resulted in a significant difference on the extraction yield. Microwave-assisted extraction after xylanase-assisted extraction was found to be the most efficient strategy for extracting hypericin. The yield was 0.319 ± 0.006 mg g ⁻¹ , which was a 209.7% increase over unassisted extraction. The combination of enzyme assisted extraction followed by microwave assisted extraction can be more commonly applied to improve extraction efficiency of bioactive compounds from plants.

Glucosinolates can be hydrolyzed by the enzyme commonly known as myrosinase (E.C. 3.2.1.147)to a variety of biological compounds. Myrosinase (MYR)has been immobilized through the flexible spacers of different length on cross-linked chitosan resin (CCR). Ethylene diamine, hexamethylenediamine and decamethylene-diamine have been separately used as spacers. The influence of the flexible spacer length on the immobilized MYR (IMYR)properties were evaluated. The optimum pH and V _max of IMYR linearly increase with the flexible spacer length, and the optimum temperature and K _m of IMYR show an opposite trend. The recyclability of IMYR was good, with 90% recovery of activity after 10 cycles and 80% recovery after 30 cycles. IMYR was highly stable under storage conditions, with 95% recovery of activity after one year storage at 4 °C. The IMYR with the longest flexible spacer, decamethylene-diamine, was used as a biocatalyst for sulforaphene production. The overall hydrolysis ratio of glucoraphenin was 93.25 ± 0.91% and the activity of DDMCCR-IMYR remained 95% after 10 days of continuous use.