Liya Cao

Phytoremediation effect of Scirpus triqueter inoculated plant-growth-promoting bacteria (PGPB) on different fractions of pyrene and Ni in co-contaminated soils

At present, few reveal the mechanism of inoculation plants with PGPB to remediate PAH-metal co-contaminated soil by analyzing the chemical speciations of contaminants. This study investigated the influence of inoculation plants with PGPB on different fractions of pyrene and Ni in rhizospheric and non-rhizospheric soil. The results demonstrated that the addition of PGPB brought the extensive increase of FDA activities in pyrene-Ni co-contaminated soil. PGPB increased the resistance of plants in nickel and pyrene-Ni contaminated soil, but decreased the plant biomass in single pyrene contaminated soil. The addition of PGPB efficiently decreased bioaccessible fractions of pyrene and increased the bioavailability of Ni in both rhizospheric and non-rhizospheric soil. Although inoculation plants with PGPB significantly increased the accumulation of Ni in single Ni and pyrene-Ni co-contaminated soil, the poor bioavailability of Ni in rhizospheric soil still restricted the phytoremediation of the heavy metal. The presence of pyrene hindered the inoculated plant from accumulating Ni to some extent. On the contrary, the presence of Ni significantly promoted the degradation of pyrene in both rhizospheric and non-rhizospheric soil after inoculation plants with PGPB.

Biodegradation of crude oil by a defined co-culture of indigenous bacterial consortium and exogenous Bacillus subtilis.

The aim of this work was to study biodegradation of crude oil by defined co-cultures of indigenous bacterial consortium and exogenous Bacillus subtilis. Through residual oil analysis, it is apparent that the defined co-culture displayed a degradation ratio (85.01%) superior to indigenous bacterial consortium (71.32%) after 7days of incubation when ratio of inoculation size of indigenous bacterial consortium and Bacillus subtilis was 2:1. Long-chain n-alkanes could be degraded markedly by Bacillus subtilis. Result analysis of the bacterial community showed that a decrease in bacterial diversity in the defined co-culture and the enrichment of Burkholderiales order (98.1%) degrading hydrocarbons. The research results revealed that the promising potential of the defined co-culture for application to degradation of crude oil.

Effect of tea saponin on phytoremediation of Cd and pyrene in contaminated soils by Lolium multiflorum

Tea saponin (TS), a kind of green biosurfactant produced by plants, was added into the Cd–pyrene co-contaminated soils to evaluate its influence on phytoremediation of Cd and pyrene by Lolium multiflorum. The results showed that the accumulation of pyrene in L. multiflorum was significantly promoted by the TS. Compared with no TS treatments (PL and ML), the aboveground concentrations of pyrene in TS treatments (PLT and MLT) increased by 135 and 30%, respectively, and the underground concentrations of pyrene in TS treatments (PLT and MLT) increased by 40 and 25%. The concentrations of Cd in the aboveground and underground parts in single contaminated treatments were all significantly more than those in co-contaminated treatments, while the situation of pyrene was quite the reverse. Besides, the addition of TS enhanced activities of dehydrogenase and polyphenol oxidase in soils and increased the biomass of L. multiflorum. The micromorphology of L. multiflorum was not affected by TS. The study suggests that the use of L. multiflorum with TS is an alternative technology for remediation of Cd–pyrene co-contaminated soils.

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.

Influence of alkyl polyglucoside, citric acid, and nitrilotriacetic acid on phytoremediation in pyrene-Pb co-contaminated soils

ABSTRACT At present, the remediation for organic pollutants and heavy metals co-contaminated soils is a challenge which needs to be broken through. In this study, alkyl polyglucoside (APG), citric acid (CA), and nitrilotriacetic acid (NTA) were chosen to enhance the phytoremediation of pyrene and Pb co-contaminated soils by perennial ryegrass. Through the comparison of the results with different applications, it could be found that the application of NTA was beneficial to the growth of perennial ryegrass, the underground and aboveground biomass were increased by 172.9–236.1% and 61.9–142.8%, respectively, meanwhile, photosynthetic activity of perennial ryegrass was affected positively. More importantly, the combined application of APG and NTA maximally promoted the accumulation and translocation of Pb (BF/TF, 0.44/0.61) and dissipation of pyrene (71.6%). These results indicated that the combined application of APG and NTA could be promising for future practical application of phytoremediation. However, the optimal dosage ratio of APG and NTA for phytoremediation needs to be further researched.

Salix integra Combined with Pseudomonas aeruginosa to Restore Diesel Contaminated Soils

AbstractThe soil remediation using Salix integra combined with oil-degraded microorganism Pseudomonas aeruginosa was conducted to investigate the effect on degradation of diesel (10,000  mg·kg−1) i...