Preparing and characterizing Fe3O4@cellulose nanocomposites for effective isolation of cellulose-decomposing microorganisms

•Fe3O4@cellulose nanocomposites for cellulose-decomposing bacteria isolation.•Bacteria capture efficiency >95.1% and stability >99.99%.•Cellulose-decomposing bacteria separation efficiency over 99.2%.•Fe3O4@cellulose can identify unknown cellulose-decomposing microbes in situ.

This study developed Fe3O4@cellulose nanocomposites by co-precipitation synthesis for bacteria capture and isolation. By surface modification with cellulose, the Fe3O4@cellulose nanocomposites have 20 nm average particle size and 3.3–24.9 emu/g saturation magnetization. Living bacteria could be captured by the Fe3O4@cellulose nanocomposites and harvested by magnetic field, with high efficiency (95.1%) and stability (>99.99%). By metabolizing cellulose and destroying the Fe3O4@cellulose@bacteria complex, cellulose-decomposing microorganisms lost the magnetism. They were therefore able to be isolated from the inert microbial community and the separation efficiency achieved over 99.2%. This research opened a door to cultivate the uncultivable cellulose-decomposing microorganisms in situ and further characterize their ecological functions in natural environment.

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