[Effects of a Symbiotic Bacterium on the Accumulation and Transformation of Arsenate by ].

Algae-bacteria consortia may be potentially applied in wastewater treatment and environment remediation. In this study, in order to investigate effects of a symbiotic bacterium on the accumulation and transformation of arsenate[As(Ⅴ)] by , we used batch cultures to determine the uptake, adsorption and transformation of As by axenic and non-axenic exposed to 0-750 μg·L As(Ⅴ) for 7 d. The symbiotic bacterium of was confirmed to be sp. after isolation, cultivation and 16S rRNA identification. The bacterial presence markedly increased the adsorption of As in , but it markedly reduced the absorption and the toxic effect of As(Ⅴ). Arsenate was the major arsenic species in the cells of axenic and non-axenic . The proportion of arsenite[As(Ⅲ)] was 8.99%-11.52% in the axenic microalga whereas a small quantity of monomethylarsonous acid (MMA) and dimethylarsinous acid (DMA) (0.02%-0.04%) were detected in the non-axenic counterpart. As(Ⅲ) dominated the As speciation in the bacterial culture and the percentage of As(Ⅴ) was 7.59%-26.80%, indicating that this symbiotic bacterium had a strong As(Ⅴ) reducing ability. The As removal rate (19.81%-41.08%) by non-axenic was higher than the bacterium alone (5.14%-14.62%) and axenic (14.98%-21.08%) after 7 d As(Ⅴ) exposure. The symbiotic sp. promoted the accumulation of As by , indicating that algae-bacteria consortia might enhance the bioremediation of As contaminated water.