A novel flocculant prepared by lignin nanoparticles-gelatin complex from switchgrass for the capture of Staphylococcus aureus and Escherichia coli

Lignin nanoparticles (L-NPs) were firstly prepared from switchgrass lignin by using ultrasonic-assisted alkali method, after which L-NPs were assembled with gelatin to constitute L-NPs-gelatin complex as a novel flocculant. Both Gram-positive (Staphylococcus aureus, S.aureus) and Gram-negative (Escherichia coli, E.coli) strains were used to investigate the flocculation property of L-NPs and L-NPs-gelatin complex. It was found that L-NPs-gelatin complex exhibited relatively better flocculation capacity than L-NPs, in which the flocculation efficiency was greatly affected by pH and dosage. For both indicator strains, flocculation efficiency (> 95%) was achieved within 30 min at pH 4.5, while the flocculation efficiency of 90% costed 60 min at pH 5. The L-NPs-gelatin complex was promising to be applied for flocculating bacteria in wastewater treatment, enrichment and detection of microorganism, etc.