Wetland bacteria isolated from Huangpu River-Yangtze River estuary and its degradation on diesel

Assessment of Pb and pyrene accumulation in Scirpus triqueter assisted by combined alkyl polyglucoside and nitrilotriacetic acid application

To understand the accumulation and uptake of polycyclic aromatic hydrocarbons (PAHs) and heavy metals by plants is an important part of the assessment of phytoremediation for PAHs and heavy metals co-contaminated soil. This study was an investigation of the accumulation and uptake of pyrene and lead (Pb) by Scirpus triqueter under the condition of alkyl polyglucoside (APG) and nitrilotriacetic acid (NTA) combined application. The results indicated that the accumulation of Pb by S. triqueter was significantly improved by NTA and APG addition into the soil. The pyrene accumulation in plant was also increased after application of APG when compared to the control treatment. However, the pyrene accumulation was decreased when APG was applied together with NTA. SEM and TEM images of root surface suggested that more Pb in the soil transferred to the plant by combined application of APG and NTA. More importantly, TEM images of xylem cells of S.triqueter root showed that permeability of cell membrane was improved by application of APG.

Diesel oil removal by immobilized Pseudoxanthomonas sp. RN402

Pseudoxanthomonas sp. RN402 was capable of degrading diesel, crude oil, n-tetradecane and n-hexadecane. The RN402 cells were immobilized on the surface of high-density polyethylene plastic pellets at a maximum cell density of 10(8) most probable number (MPN) g(-1) of plastic pellets. The immobilized cells not only showed a higher efficacy of diesel oil removal than free cells but could also degrade higher concentrations of diesel oil. The rate of diesel oil removal by immobilized RN402 cells in liquid culture was 1,050 mg l(-1) day(-1). Moreover, the immobilized cells could maintain high efficacy and viability throughout 70 cycles of bioremedial treatment of diesel-contaminated water. The stability of diesel oil degradation in the immobilized cells resulted from the ability of living RN402 cells to attach to material surfaces by biofilm formation, as was shown by CLSM imaging. These characteristics of the immobilized RN402 cells, including high degradative efficacy, stability and flotation, make them suitable for the purpose of continuous wastewater bioremediation.