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Abstract Background Phosphate-solubilizing bacteria (PSB) can solubilize insoluble phosphate compounds and improve phosphate availability in soil. Road verges are important in urban landscaping, but the population structure of PSB and their ecological functions in the road verge soil is still unclear. Results Twenty-one mineral PSB strains and 14 organic PSB strains were isolated from the rhizosphere of poplar on urban road verge. All the mineral PSB strains showed better solubilization to Ca3(PO4)2 than FePO4 or AlPO4. Among them, 7 strains showed high phosphate-solubilizing (PS) activities to Ca3(PO4)2 (150–453 mg/L). All the organic PSB strains displayed weak solubilization to lecithin. 16S rRNA gene-based phylogenetic analysis showed good species diversity of the PSB strains, which belongs to 12 genera: Bacillus, Cedecea, Cellulosimicrobium, Delftia, Ensifer, Paenibacillus, Pantoea, Phyllobacterium, Pseudomonas, Rhizobium, Sinorhizobium and Staphylococcus. Moreover, 8 PSB strains showed various degrees of growth inhibition against 4 plant pathogenic fungi, Fusarium oxysporum S1, F. oxysporum S2, Pythium deliense Meurs Z4, Phomopsis sp. AC1 and a plant pathogenic bacterium, Pectobacterium carotovorum TP1. Conclusions The results indicated that these PSB strains could perform multiple ecological functions on road verge. The development and application of bio-agents based on the strains would provide a new strategy for maintaining and improving the ecosystem stability of road verges.

This study evaluated the formation of bromate (Br) in the catalytic ozonation with cerium oxide (CeO2) compared with single ozonation and several catalytic ozonation with metal oxides (i.e. magnesium oxide (MgO) and synthetic goethite (FeOOH)). The results showed that the least Brwas generated in the O3/CeO2system. Primary experiments have confirmed that both Br−and Brcould be hardly adsorbed by CeO2, and thus the inhibition of Brin the O3/CeO2process was mainly ascribed to the effect of CeO2on the ozone decomposition and subsequent hydroxyl radical () formation in the bulk solution. Firstly, the degradation of para-chloronitrobenzene (pCNB) was examined and the results showed that less pCNB was degraded by O3/CeO2than single ozonation, suggesting thatformation was inhibited in the O3/CeO2system. Furthermore, the effect of inorganic anions (i.e. sulfate (S) and nitrate (N)) on the systems was investigated. It was found that Shad a negative effect on the Brinhibition in the O3/CeO2process, which was due to that Sinhibited the adsorption of O3and oxygen-containing species by CeO2through competing the active sites of CeO2. Moreover, the inhibition of Brformation in the catalytic ozonation with the CeO2samples calcined at different temperatures was also studied. The results showed that the efficiency of inhibition decreased in the following sequence CeO2(450°C) > CeO2(650°C) > CeO2(250°C). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses on the CeO2specimens showed that CeO2(450°C) had the highest Ce(IV) to Ce(III) ratio and the least lattice oxygen and adsorbed oxygen amount. Therefore, a new mechanism about the inhibition of Brformation in the O3/CeO2system was proposed. Both O3molecules and some oxygen-containing intermediates from O3decomposition in solution will be adsorbed on the active sites of CeO2, and the less lattice and adsorbed oxygen also promote the adsorption of oxygen-containing species on the CeO2surface. This will result in the inhibition of O3decomposition intoin solution and thus inhibition of Brformation. This study improves our understanding of the O3/CeO2process for controlling Brformation and also guides the practical application. [ABSTRACT FROM PUBLISHER]