The new biocatalytic membrane removes micropollutants efficiently and stably

Micropollutants such as endocrine disruptors, pesticides and pharmaceuticals have detrimental effects on public health and aquatic ecosystems, including at trace levels. Biocatalytic membranes show a high efficiency of removal of micropollutants thanks to the integration of enzymatic catalysis and membrane separation.

Achieving long-term stability and high catalytic efficiency at the same time remains a challenge in the fabrication of biocatalytic membranes. Inspired by the fluid mosaic model of the cell membrane structure, a research team led by Prof. Wan Yinhua of the Process Engineering Institute (IPE) of the Chinese Academy of Sciences prepared a new biocatalytic membrane with high enzymatic activity and stability. for the removal of micropollutants. The study was published in Journal of Chemical Engineering on November 28.

Researchers adjusted the confinement strength of the membrane, thereby regulating the mobility of the immobilized enzyme via the three-dimensional (3-D) modification of the support layer of the nanofiltration membrane.

A mussel-inspired coating was applied to modify the entire support layer of the nanofiltration membrane (referred to as 3-D modification) and the laccase was subsequently non-covalently limited in a modified nanofiltration membrane by reverse filtration.

“Laccase can be stabilized in the modified 3-D support layer of the nanofiltration membrane with uniform distribution, high enzymatic load and extremely high storage stability. In addition, the modified nanofiltration membrane is versatile for different enzymatic immobilization. “, said Prof. Pallido.

Even better, this mussel-inspired 3-D modification strategy improved membrane confinement strength to the enzyme with a small increase in mass transfer resistance for substrate and products, which effectively delayed enzyme leakage and at the same time it endowed the enzyme with a level of mobility for efficient catalysis.

The biocatalytic membrane prepared with optimized confinement force showed high catalytic activity and long-term stability in seven cycles of reuse and 36 hours of continuous operation for the removal of micropollutants.

The researchers also proposed a simple protocol to quantify the mobility of the immobilized enzyme, which could precisely reflect the confinement strength of modified membranes, as well as the catalytic performance of biocatalytic membranes.

In addition, the modified membrane could serve as an enzyme storage device and controllable sustained release device for reaction and dosage. “This work not only offers a versatile platform to immobilize various enzymes and prepare a superior biocatalytic membrane,” said prof. Luo Jianquan of IPE, “but also provides guidance for designing an optimal confinement environment for enzymes in the membrane, facilitating potential applications of the biocatalytic membrane for improved bioconversion, drug delivery and small-scale biosensors.”