Dual-roles of carbon black to accelerate phosphorus recovery as vivianite.

Carbon materials have been confirmed to promote phosphorus recovery as vivianite through enhancing dissimilatory iron reduction (DIR), which alleviates phosphorus crisis. Carbon black (CB) exhibits contradictory dual roles of cytotoxicity inducer and electron transfer bridge towards extracellular electron transfer (EET). Herein, the effect of CB on vivianite biosynthesis was investigated with dissimilatory iron reduction bacteria (DIRB) or sewage. With Geobacter sulfurreducens PCA as inoculum, the vivianite recovery efficiency increased accompanied with CB concentrations and enhanced by 39 % with 2000 mg·L-1 CB. G. sulfurreducens PCA activated the adaptation mechanism of secreting extracellular polymeric substance (EPS) to resist cytotoxicity of CB. While in sewage, the highest iron reduction efficiency of 64 % was obtained with 500 mg·L-1 CB, which was appropriate for functional bacterial selectivity like Proteobacteria and bio-transformation from Fe(III)-P to vivianite. The balance of CB's dual roles was regulated by inducing the adaptation of DIRB to gradient CB concentrations. This study provide an innovative perspective of carbon materials with dual roles for vivianite formation enhancement.

Vivianite recovery from high concentration phosphorus wastewater with mine drainage as iron sources.

High concentration phosphorus wastewater has attracted much attention due to the safety of water ecology and the potential crisis of phosphorus resource, which is caused by large amounts of phosphorus discharging into natural water bodies. Vivianite (Fe3(PO4)2·8H2O) crystallization has been considered as an effective technology for phosphorus recovery. In this study, we develop a potentially low-cost, sustainable approach to recover phosphorus from high concentration phosphorus wastewater using mine drainage as iron source. Inoculated with both sewage and Geobacter, mine drainage was suitable for vivianite recovery from high concentration phosphorus wastewater with PO43- concentration between 6 and 18 mM. When the PO43- concentration increased gradually, both phosphorus removal efficiency (RP) and vivianite recovery efficiency (RV) decreased significantly. The highest RV of 48 % was obtained with 9 mM PO43- in Geobacter batches (CJ2 batches), which was 15 % higher than that in the paralleled sewage batches (33 % in HJ2). Simultaneously, vivianite accounted for 91 % of the solid phosphate compounds in CJ2 batches due to the enhancement of Geobacter.

Characterization of the complete chloroplast genome of Melaleuca cajuputi subsp. cumingiana (Myrtaceae).

Plants in the genus Melaleuca have been widely used as traditional medicine mainly because of their broad spectrum antimicrobial activity. In this study, we reported the complete chloroplast genome of Melaleuca cajuputi subsp. cumingiana. The chloroplast genome of this species is 158,855 bp in length, including a pair of inverted repeat regions (IRs) (26,727 bp) that is divided by a large single-copy (LSC) area (87,338 bp) and a small single-copy (SSC) area (18,063 bp). The circular chloroplast genome of M. cajuputi subsp. cumingiana contains 135 unique genes, composing of 87 protein-coding genes, 40 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicates that M. cajuputi subsp. cumingiana was clustered with species in the tribe Melaleuceae. This complete chloroplast genome of M. cajuputi subsp. cumingiana will provide a powerful tool to accelerate breeding, biotechnological and phylogenetic study.