Halomonas daqingensis sp. nov., a moderately halophilic bacterium isolated from an oilfield soil.

A Gram-negative, moderately halophilic, short rod-shaped, aerobic bacterium with peritrichous flagellae, strain DQD2-30(T), was isolated from a soil sample contaminated with crude oil from the Daqing oilfield in Heilongjiang Province, north-eastern China. The novel strain was capable of growth at NaCl concentrations of 1-15 % (w/v) [optimum at 5-10 % (w/v)]. Phylogenetic analyses based on 16S rRNA gene sequences showed that the novel strain belonged to the genus Halomonas in the class Gammaproteobacteria; the highest 16S rRNA gene sequence similarities were with Halomonas desiderata DSM 9502(T) (98.8 %), Halomonas campisalis A4(T) (96.6 %) and Halomonas gudaonensis CGMCC 1.6133(T) (95.1 %). The major cellular fatty acids of strain DQD2-30(T) were C(18 : 1)omega7c (43.97 %), C(19 : 0 )cyclo omega8c (23.37 %) and C(16 : 0) (14.83 %). The predominant respiratory lipoquinone was ubiquinone with nine isoprene units (Q9). The DNA G+C content was 67.0 mol%. The DNA-DNA hybridization values of strain DQD2-30(T) with the most closely related species of the genus Halomonas were 51.8 %, 28.4 % and 23.5 % for H. desiderata, H. campisalis and H. gudaonensis, respectively. Based on these analyses, strain DQD2-30(T )(=CGMCC 1.6443(T)=LMG 23896(T)) is proposed to represent the type strain of a novel species, Halomonas daqingensis sp. nov.

Adsorption removal of phosphate from aqueous solution by active red mud.

Red mud is the waste of alumina industry and has high TiO2 and Fe2O3 content which are active components for the adsorption of anion pollutants. In this study, the uptake of phosphate by red mud activated by heat treatment and acid-heat treatment was investigated. The factors influencing the adsorption were also investigated. The result showed that the red mud sample treated using acid-heat method at 80 degrees C with 0.25 mol/L HCl for 2 h achieved the highest phosphate removal. For the heat-activated red mud, the sample heated at 700 degrees C for 2 h preformed better than the other heat treatment. Phosphate removal by the activated red mud was significantly pH dependent, and pH 7 was the optimal pH for phosphate removal. The adsorption fits Langmuir isotherm model well and the maximum adsorption capacities of the acid-heat activated red mud and the heat activated samples were 202.9 mgP/g and 155.2 mgP/g, respectively.