Isolation and Characterization of a Biosurfactant Producing Strain Planococcus sp. XW-1 from the Cold Marine Environment.

One cold-adapted strain, named Planococcus sp. XW-1, was isolated from the Yellow Sea. The strain can produce biosurfactant with petroleum as sole source of carbon at low temperature (4 °C). The biosurfactant was identified as glycolipid-type biosurfactant species by thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FTIR). It reduced the surface tension of water to 26.8 mN/m with a critical micelle concentration measurement of 60 mg/L. The produced biosurfactant possesses high surface activity at wide ranges of temperature (-18-105 °C), pH values (2-12), and salt concentrations (1-18%). The biosurfactant exhibited higher surface activity and higher growth rate of cells with hexadecane and diesel as carbon source. The strain Planococcus sp. XW-1 was also effective in degrading crude oil, after 21 days of growth at 4 °C in medium with 1% crude oil and 1% (v/v) bacteria broth, 54% of crude oil was degraded. The results suggest that Planococcus sp. XW-1 is a promising candidate for use in the bioremediation of petroleum-contaminated seawater in the Yellow Sea during winter. This study reported for the first time that Planococcus isolated from the Yellow Sea can produce biosurfactant using petroleum as the sole carbon source at low temperature (4 °C), showing its ecological role in the remediation of marine petroleum pollution.

Adsorption studies of cadmium onto magnetic Fe3O4@FePO4 and its preconcentration with detection by electrothermal atomic absorption spectrometry.

Superparamagnetic Fe3O4@FePO4 nanoparticles with core shell structure were prepared by coating iron phosphate on the surface of Fe3O4 nanoparticles by liquid phase deposition method. The prepared materials were characterized by vibrating sample magnetometer, scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectrometer, nano Zetasizer, X-ray photoelectron spectroscopy and Raman spectrometer. These characterization methods were also used to describe the adsorption mechanism. The obtained composite material was used for the adsorption of a heavy metal element, cadmium. Its unique magnetic properties are favorable for rapid separation and preconcentration of trace cadmium from aqueous solutions. About 100% sorption was achieved at pH 7 for 1mL, 10µgL-1 of cadmium. Batch adsorption experiments show that the adsorption fits Langmuir model, and a maximum adsorption capacity 13.51mgg-1 is derived for Cd(II). The retained Cd(II) could be readily recovered by 200µL of HNO3 (0.01molL-1). The cadmium in the eluate is quantified with detection by electrothermal atomic absorption spectrometry (ETAAS). A sample volume of 2000µL creates an enrichment factor of 10.3, along with a detection limit of 0.021µgL-1 (3σ, n=7) and a RSD of 1.3% (0.1µgL-1, n=7) within a linear calibration range of 0.05-0.5µgL-1. The practical applicability of this procedure was validated by analyzing cadmium contents in a certified reference material (GBW08608) and two environmental water samples.

Draft Genome Sequence of the Crude Oil-Degrading and Biosurfactant-Producing Strain Cobetia sp. QF-1.

We report here the draft genome of Cobetia sp. QF-1, a cold-adapted bacterium isolated from crude oil-contaminated seawater of the Yellow Sea, China. This genome is approximately 4.1 Mb (G+C content, 57.44%) with 3,513 protein-coding sequences. Cobetia sp. QF-1 shows crude oil degradation and biosurfactant production activity at low temperature.

Sulfate reduction and mixotrophic sulfide-utilization denitrification integrated biofilm process for sulfate-laden wastewater treatment and sulfur recovery.

A novel and integrated biofilm process--the sulfate reduction (SR) and mixotrophic (MR) sulfide-utilization denitrification process (SMSD)--was recently proposed for sulfate treatment and sulfur recovery. The process consisted of two bioreactors: a 5.1 L anaerobic upflow reactor for SR, and a 3.5 L anaerobic upflow reactor for MR desulfurization-denitrification. The experiment was conducted for 370 days to evaluate the performance of SMSD at various sulfate concentrations and hydraulic retention times. The process successfully achieved sulfate, organics and nitrogen compound removal efficiencies of 94.1, 97.7 and 99.1%, respectively. Sulfate was predominantly converted to element sulfur, while nitrate and nitrite were finally converted to nitrogen gas. In SR, with the help of high pH and sponge cubes with various bacteria, 97.5% of sulfide conversion efficiency and 540 mgS/L of sulfide were obtained. In MR, sulfide was removed up to 100% and was partially oxidized to sulfur. The extent of heterotrophic denitrification, which ranged from 35.8 to 59.8%, depended on the categories of electron acceptors.