Extraction of allelochemicals from poplar alkaline peroxide mechanical pulping effluents and their allelopathic effects on Microcystis aeruginosa

In this study,allelochemicals were extracted from pulping effluents rather than from the raw ma-terial of plants.Herein,five organic solvents(ethyl acetate(EAC),methyl tert-butyl ether(MTBE),dichloromethane(DCM),carbon tetrachloride(CTC),and petroleum(PE))were applied to sep-arately extracting the allelochemicals from alkaline peroxide mechanical pulp(APMP)effluents.The results from the algal density,inhibition ratio,and optical density of 446 nm(OD 446nm)concluded that the extractives from the APMP effluents can act as effective allelochemicals and showed noticeable allelopathic inhibition effects on Microcystis aeruginosa growth.The results in-dicated that organic solvent extraction could be a practical approach to isolate the allelochemicals from the APMP effluents,which would broaden the potential application of the APMP effluents in the production of antimicrobial agents and other value-added materials.

Research on Bast Fiber Extracted from the White Bark of Three Species in the Genus Broussonetia

Against the backdrop of a global paper resource shortage,there is a growing need to identify fast-growing tree species capable of producing long-lasting paper.Three plant species namely Broussonetia kazinoki,Broussonetia papyrifera and hybrid paper mulberry,belong to the Broussonetia genus,were collected from China to study their white bark suitability for pulp and papermaking.Their chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%.The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC,which allows us to better observe the changes of various components on the molecular weight.The yield,lignin,whiteness,and molecular weight of the pulps obtained by NaOH treatment were determined.Optical microscope was used to characterize the fiber length-width ratio and rigidity.Finally,the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber rigidity.This study demonstrates the high potentiality of these three species for papermaking applications.