Optimization of growth condition for hydrocarbon degrading bacteria isolated from oily sludge in order to achieve the most efficient conditions in environmental bioremediation
Petroleum refineries around the world have generated the solid wastes during the refining process and stocking of crude oil. Oily sludge leads to destructive effects in the environment. This investigation concentrated in degrading oily compounds from oily sludge in order to environmental bioremediation. Eight bacterial strains able to grow on the oily sludge as sole source of carbon and energy isolated from oily sludge and soil-contaminated with oily sludge in Abadan refinery. Two bacterial strains were adopted as efficient strains and were named AOR1 and AOR2. Influence of different nitrogen and phosphorous sources on the growth of these two bacterial strains were investigated by measuring the growth rate through serial dilution and colony counting in T.S.A medium. Sodium nitrate and disodium hydrogen phosphate were found to be the best nitrogen and phosphorous sources for the AOR1 strain. Ammonium chloride and diammonium hydrogen phosphate were found to be the best nitrogen and phosphorous sources for the AOR2 strain. It can be concluded that these isolates have potential for environmental pollution bioremediation and supplying these nitrogen and phosphor resources to their medium can accelerate this process.
Evaluation of Inoculum Addition To Stimulate In Situ Bioremediation of Oily-Sludge-Contaminated Soil
ABSTRACT A full-scale study evaluating an inoculum addition to stimulate in situ bioremediation of oily-sludge-contaminated soil was conducted at an oil refinery where the indigenous population of hydrocarbon-degrading bacteria in the soil was very low (103 to 104 CFU/g of soil). A feasibility study was conducted prior to the full-scale bioremediation study. In this feasibility study, out of six treatments, the application of a bacterial consortium and nutrients resulted in maximum biodegradation of total petroleum hydrocarbon (TPH) in 120 days. Therefore, this treatment was selected for the full-scale study. In the full-scale study, plots A and B were treated with a bacterial consortium and nutrients, which resulted in 92.0 and 89.7% removal of TPH, respectively, in 1 year, compared to 14.0% removal of TPH in the control plot C. In plot A, the alkane fraction of TPH was reduced by 94.2%, the aromatic fraction of TPH was reduced by 91.9%, and NSO (nitrogen-, sulfur-, and oxygen-containing compound) and asphaltene fractions of TPH were reduced by 85.2% in 1 year. Similarly, in plot B the degradation of alkane, aromatic, and NSO plus asphaltene fractions of TPH was 95.1, 94.8, and 63.5%, respectively, in 345 days. However, in plot C, removal of alkane (17.3%), aromatic (12.9%), and NSO plus asphaltene (5.8%) fractions was much less. The population of introduced Acinetobacter baumannii strains in plots A and B was stable even after 1 year. Physical and chemical properties of the soil at the bioremediation site improved significantly in 1 year.
A preliminary account of a new tyrannosauroid theropod from the Wessex Formation (Early Cretaceous) of southern England
Abstract A new genus and species of coelurosaurian theropod dinosaur from the Wessex Formation (Early Cretaceous, Barremian) of the Isle of Wight, England, is described and named. Distinctive characters of the premaxilla, its dentition, maxilla and nasals allow it to be diagnosed. The teeth in the premaxilla are D-shaped in cross-section and the nasals are fused. The hands are elongate and slender and the hindlimbs are gracile. Lack of element fusion elsewhere in the skeleton suggests that it is a subadult. Numerous character states are shared with tyrannosaurids but the new taxon appears to be excluded from the group that comprises aublysodontine and tyrannosaurine tyrannosaurids. We conclude that the taxon is a basal tyrannosauroid and as such it is one of the earliest and (with the exception of some teeth and an isolated ilium from Portugal) the first from Europe. Implications for tyrannosauroid biogeography and evolution are discussed. The animal was part of an unusual taphonomic assemblage in which some elements were partially articulated while others were scattered or broken.