Electrospinning micro-nanofibers immobilized aerobic denitrifying bacteria for efficient nitrogen removal in wastewater

Electrospinning micro-nanofibers with exceptional physicochemical properties and biocompatibility are becoming popular in the medical field. These features indicate its potential application as microbial immobilized carriers in wastewater treatment. Here, aerobic denitrifying bacteria were immobilized on micro-nanofibers, which were prepared using different concentrations of polyacrylonitrile (PAN) solution (8%, 12% and 15%). The results of diameter distribution, specific surface area and average pore diameter indicated that 15% PAN micro-nanofibers with tighter surface structure were not suitable as microbial carriers. The bacterial load results showed that the cell density (OD600) and total protein of 12% PAN micro-nanofibers were 107.14% and 106.28% higher than those of 8% PAN micro-nanofibers. Subsequently, the 12% PAN micro-nanofibers were selected for aerobic denitrification under the different C/N ratios (1.5-10), and stable performance was obtained. Bacterial community analysis further manifested that the micro-nanofibers effectively immobilized bacteria and enriched bacterial structure under the high C/N ratios. Therefore, the feasibility of micro-nanofibers as microbial carriers was confirmed. This work was of great significance for promoting the application of electrospinning for microbial immobilization in wastewater treatment.

Automated summary

Electrospinning micro-nanofibers are gaining popularity in the medical field due to their exceptional physicochemical properties and biocompatibility, making them ideal for use as microbial immobilized carriers in wastewater treatment. This study immobilized aerobic denitrifying bacteria on micro-nanofibers made from different concentrations of polyacrylonitrile (PAN) solution. The results showed that 15% PAN micro-nanofibers with a tighter surface structure were not suitable as microbial carriers, while 12% PAN micro-nanofibers demonstrated higher cell density and total protein, making them the optimal choice for aerobic denitrification.