Isolation, identification and characterization of Bacillus amyloliquefaciens BZ-6, a bacterial isolate for enhancing oil recovery from oily sludge

Over 100 biosurfactant-producing microorganisms were isolated from oily sludge and petroleum-contaminated soil from Shengli oil field in north China. Sixteen of the bacterial isolates produced biosurfactants and reduced the surface tension of the growth medium from 71 to <30 mN m⁻¹ after 72 h of growth. These bacteria were used to treat oily sludge and the recovery efficiencies of oil from oily sludge were determined. The oil recovery efficiencies of different isolates ranged from 39% to 88%. Bacterial isolate BZ-6 was found to be the most efficient strain and the three phases (oil, water and sediment) were separated automatically after the sludge was treated with the culture medium of BZ-6. Based on morphological, physiological characteristics and molecular identification, isolate BZ-6 was identified as Bacillus amyloliquefaciens. The biosurfactant produced by isolate BZ-6 was purified and analyzed by high performance liquid chromatography-electrospray ionization tandem mass spectrometry. There were four ion peaks representing four different fengycin A homologues.     

Is research keeping up with changes in landscape policy? A review of the literature

Several innovative directions for landscape policy development and implementation have emerged over recent years. These include: (i) an expansion of scope to include all landscape aspects and landscape types, (ii) an increased emphasis on public participation, (iii) a focus on designing measures appropriate for different contexts and scales, and (iv) encouraging support for capacity-building. In this paper, we evaluate the extent to which these policy directions are reflected in the practice of academic landscape research. We evaluate all research papers published in three leading landscape journals over six years, as well as published research papers relating directly to the European Landscape Convention. The latter, which was adopted in 2000, establishes a framework for landscape protection, planning and management in Europe and is to date the only international legal instrument of its kind. Results indicate that whilst policy innovations do not appear to be a major stimulus for academic research, studies nevertheless address a range of landscape aspects, types and scales (albeit with a slight bias towards bio-physical landscape aspects). However, geographical representativeness of research is weak and dominated by the United States and northern/western Europe, and research capacity likewise appears to be unevenly distributed. Landscape research is also limited in the extent to which it involves stakeholders or develops innovative methods for doing so, notwithstanding that this remains a key challenge for policy-makers. Results point to the potential for landscape research to address areas (topical and geographical) which have received little attention to date, as well as suggesting mutual benefits of stronger links between policy and academia.     

Methyl-β-cyclodextrin enhanced biodegradation of polycyclic aromatic hydrocarbons and associated microbial activity in contaminated soil

The contamination of soils by polycyclic aromatic hydrocarbons (PAHs) is a widespread environmental problem and the remediation of PAHs from these areas has been a major concern.The effectiveness of ma...     

Survival of faecal coliforms and hygiene risks in soils treated with municipal sewage sludges

An incubation experiment was conducted to monitor effect of sewage sludge application on changes in numbers of faecal coliforms in soils over time after sludge application and evaluate the hygiene risks. Soil faecal coliform counts were made after 1, 7, 14, 28, 56 and 84 days of incubation. The faecal coliform counts in the sludge-treated soils decreased substantially with time and were similar to those in the untreated controls after incubation for 56 days. Land application of air-dried sludges increased the hygiene risks due to the re-growth of faecal coliforms, and the counts of faecal coliforms in soil treated with air dried sludge from Suzhou (91% DM) were 50 times higher than in soils with fresh dewatered sludge from Suzhou (15% DM) after 7 days of incubation. The main factors affecting the changes in faecal coliform counts were sludge type and incubation time. Sludge type determined the faecal coliform counts and the ability of the faecal coliforms to re-establish, and indigenous microorganisms competed with the faecal coliforms for nutrients during the incubation process.     

Uptake of Zn by arbuscular mycorrhizal white clover from Zn-contaminated soil

A randomised block glasshouse pot experiment compared the growth and Zn uptake of mycorrhizal and nonmycorrhizal white clover plants grown in a sterile soil/sand mixture containing 25 mg Zn kg(-1) to which five application rates of Zn (as ZnSO4) from 0 to 400 mg kg(-1) were made. Two mycorrhizal inocula infected roots from the field and from clover trap cultures, were compared. Mycorrhizal infection (ranging from 33% to 46% of total root length) and Zn application had little effect on plant growth. Increasing Zn application rate led to increased uptake of Zn in roots and shoots (especially roots), but the increases were significantly greater in non-mycorrhizal controls than in mycorrhizal treatments. In contrast, P uptake was higher in mycorrhizal than in non-mycorrhizal plants. Plants that received trap culture inoculum had significantly lower Zn uptake than those that received field inoculum. The results indicate that mycorrhizal infection may have exerted some protective effect against plant Zn accumulation at the range of soil Zn concentrations studied and may have immobilised Zn in or near the roots to some extent. However, this mycorrhizal effect cannot be explained simply by tissue dilution, hyphal sequestration or root immobilisation of Zn.     

Novel use of soil moisture samplers for studies on anaerobic ammonium fluxes across lake sediment-water interfaces

Small soil suction samplers have been used for several years to sample soil solution for chemical analysis in laboratory and glasshouse experiments. They are very cheap, effective and convenient. Here we describe for the first time their use in studies on sediment porewater. Bulk sediment from West Lake, a shallow hypereutrophic lake in Hangzhou, Zhejiang Province, China, was placed in laboratory microcosms and incubated in the dark at 25 degrees C for 182 days to evaluate the feasibility of using the samplers to extract sediment porewater and to estimate NH4+ flux across the sediment-water interface under anaerobic conditions. The results show that the samplers were capable of sequentially extracting sediment porewater, 15 ml of which could be readily extracted for analysis within 30-45 min by vacuum applied using a plastic syringe. The NH4+ flux under laboratory conditions was characterized by a fast phase during the initial 18 days of incubation followed by a slower linear phase, with average release rates of 11.6 and 3.6 mg N m(-2) d(-1), respectively.     

Growth and nutrient uptake of arbuscular mycorrhizal maize in different depths of soil overlying coal fly ash

Application of topsoil over phytotoxic mine wastes is often practised to establish perennial plant communities on minespoil areas. In China, population pressure encourages attempts to remediate such areas by growing arable crop plants, but efforts to establish agricultural crops often fail. We report an outdoor pot experiment that compared the effects of two arbuscular mycorrhizal (AM) fungi, Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe and G. versiforme (Karsten) Berch, on the growth and nutrient uptake of maize (Zea mays L.) grown in different depths of soil layer overlying coal fly ash. Colonization by both AM fungi increased plant growth compared with non-mycorrhizal controls, with G. mosseae giving higher yields of maize than G. versiforme at the same depths of soil. Increasing soil depth led to increased plant yields. Mycorrhizal plants absorbed more nutrients than non-mycorrhizal controls, and translocated less Na to the shoots, perhaps protecting the plants from excessive Na accumulation. These preliminary results indicate that arbuscular mycorrhizas may make a substantial contribution to successful crop establishment in soils overlying areas of coal fly ash.     

Carbon storage in eucalyptus and pine plantations in South Africa

Carbon (C) is stored by plantation forests either when ecosystems with a low C density (such as tropical grasslands) are afforested or when timber is converted to semipermanent products. If the afforestation rate is relatively constant and the plantations are not harvested immediately upon reaching maturity, the amount of C stored in trees as a result of afforestation can be calculated by a simple static approximation. Rotation forestry requires a mean C storage method that averages C density over the rotation. Plantation forestry as practiced in South Africa requires a more detailed dynamic approach that accounts for time-varying rates of afforestation and the age-dependence of C accumulation rates in plantations. To determine C storage in products, the output of long-lived plantation products and their C content once all processing losses are accounted for must be known. The South African case study shows that new afforestation stored approximately 2.54 Tg C in 1990, and storage in forest products accounted for an additional 1.15 Tg C. Together, these two activities offset approximately 3.8% of the carbon dioxide emissions from South Africa.