Preparing and characterizing Fe 3 O 4 @cellulose nanocomposites for effective isolation of cellulose-decomposing microorganisms

Abstract

This study developed Fe3O4@cellulose nanocomposites by coprecipitation 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.Magnetic nanoparticles (MNPs) have been widely applied in biomedical and biological research.Surface modified MNPs are recently used to investigate the microbial behavior and functions in a complex microbiota, but the modification method is not well established for wider range of functional bacteria. This study developed a new surface modification method and synthesized the Fe 3 O 4 @cellulose nanocomposites.The bacterial capture efficiency was above 95.1% and the stability is above 99.99%. More importantly, the Fe 3 O 4 @cellulose nanocomposites successfully isolate the cellulose-decomposing Aeromonasveronii from an artificial microbial community.This work broadens the applicable potential of MNPs in assessing more unknown cellulose-decomposing bacteria in natural environment and their metabolic pathways. Novelty statement Fe3O4@cellulose nanocomposites can be used for the first time to isolate cellulosedecomposing bacteria from complex microbial community.  Fe3O4@cellulose achieves high bacteria capture efficiency (>95.1%) and stability (>99.99%).  Fe3O4@cellulose successfully isolates cellulose-decomposing Aeromonasveroniiand the separation efficiency is 99.2%.Thanks for the reviewers' comments and editors's suggestion. We have corrected the manuscript by adding Figure S1, 2 and 3 into the main manuscript and correcting the Figure number and caption.Response to Reviewers Magnetic field isolation Raw magnetic nanoparticles (MNPs) Fe 3 O 4 @cellulose nanocomposites Acinetobacter baylyi (no cellulose-decomposing capacity) Aeromonas veronii (cellulose-decomposing bacterium) MNPs synthesis Cellulose functionalization Fe 3 O 4 @cellulose nanocomposites Bacteria functionalization Cultivation and cellulose decomposing Graphical Abstract Highlight 1. Fe 3 O 4 @cellulose nanocomposites for cellulose-decomposing bacteria isolation. 2. Bacteria capture efficiency >95.1% and stability >99.99%. 3. Cellulose-decomposing bacteria separation efficiency over 99.2%. 4. Fe 3 O 4 @cellulosecan identify unknown cellulose-decomposingmicrobesin situ. AbstractThis study developed Fe 3 O 4 @cellulose nanocomposites by co-precipitation synthesis for bacteria capture and isolation. B...

One-step synthesis of magnetic-TiO2-nanocomposites with high iron oxide-composing ratio for photocatalysis of rhodamine 6G

“…All the chemicals used in this study were of analytical grade and purchased from Sigma Aldrich (UK). One-step synthesis of TiO 2 -composing MNPs followed the previously reported coprecipitation method with modifications [30,31]. Briefly, 2 mL FeCl 3 (1.0 M) and 1 mL FeCl 2 (2.0 M) were gently mixed and added with 20 mL titanium isopropoxide (TTIP, 97%) and isopropanol (IPA, ≥99.7%).…”

Magnetic cellulose: does extending cellulose versatility with magnetic functionality facilitate its use in devices?

“…In situ incorporation Ex situ incorporation Iron oxide Co-precipitation in cellulose matrix: cellulose suspension, 47,48,51 cellulose solution 49,50,[56][57][58] Preformed particles: added to cellulose solution; 49,[52][53][54][55][59][60][61][62] surface modification of cellulose prior; 63 using a retention aid 71 Hydrothermal methods 68…”

“…51 The co-precipitation has been mostly performed in a matrix of various cellulose material hierarchies (Table 1), thereby producing hybrid particles comprising organic cellulose and inorganic iron oxide phases. The same method has been applied to produce magnetic cellulose in solution by first dissolving the cellulose in, for example, NaOH/urea at low temperature and combining the cellulose solution with pre-formed magnetic particles [52][53][54][55] or dropwise addition of a solution of FeCl 3 and FeCl 2 into the solution. 56,57 Cellulose xanthate, that is a soluble intermediate in viscose production and can be regenerated to cellulose, was functionalized with iron oxide particles by adding premade particles as well as in a one-step synthesis by adding an iron source into the xanthate solution.…”

Cellulose stabilized Fe3O4and carboxylate‐imidazole and Co‐based MOF growth as an exceptional catalyst for the Knoevenagel reaction

“…Among these modifiers, cellulose as a biopolymer has attracted substantial attention owing to its biodegradability, biocompatibility, and outstanding thermal properties. Therefore, cellulose can be utilized as an effective coating material for Fe 3 O 4 nanoparticles to yield environmentally friendly, biocompatible, and exciting biopolymer‐based nanocomposites …”