Bioremediation of soils saturated with spilled crude oil

Abstract

A desert soil sample was saturated with crude oil (17.3%, w/w) and aliquots were diluted to different extents with either pristine desert or garden soils. Heaps of all samples were exposed to outdoor conditions through six months, and were repeatedly irrigated with water and mixed thoroughly. Quantitative determination of the residual oil in the samples revealed that oil-bioremediation in the undiluted heaps was nearly as equally effective as in the diluted ones. One month after starting the experiment. 53 to 63% of oil was removed. During the subsequent five months, 14 to 24% of the oil continued to be consumed. The dynamics of the hydrocarbonoclastic bacterial communities in the heaps was monitored. The highest numbers of those organisms coordinated chronologically with the maximum oil-removal. Out of the identified bacterial species, those affiliated with the genera Nocardioides (especially N. deserti), Dietzia (especially D. papillomatosis), Microbacterium, Micrococcus, Arthrobacter, Pseudomonas, Cellulomonas, Gordonia and others were main contributors to the oilconsumption. Some species, e.g. D. papillomatosis were minor community constituents at time zero but they prevailed at later phases. Most isolates tolerated up to 20% oil, and D. papillomatosis showed the maximum tolerance compared with all the other studied isolates. It was concluded that even in oilsaturated soil, self-cleaning proceeds at a normal rate. When pristine soil receives spilled oil, indigenous microorganisms suitable for dealing with the prevailing oil-concentrations become enriched and involved in oil-biodegradation.

Genomic diversity of bacteriophages infecting Microbacterium spp

“…These Microbacterium phages should be a rich source of tools for dissecting and manipulating Microbacterium strains. In addition to involvement in human infections, Microbacterium strains have been implicated in nitrogen fixation [53] and have potential biotechnological applications [54]. Microbacterium phages could be exploited to develop integration-proficient plasmid vectors using the integrase systems in the Cluster EH and Singleton Zeta1847 phages, for recombineering systems using the Exo/Recombinase systems such as those in the Cluster EC, EI, and singleton Appa phages, and for phage-delivery of transposons, allelic exchange substrates, and reporter genes; this mirrors the utilities derived from mycobacteriophages for mycobacterial genetics [1].…”

Bioremediation of Crude Oil Contaminated Soil Using Pig Droppings and Bone Char

“…The setup was thoroughly mixed and watered with 4 ml of distilled water every two (2) days to keep the moisture content constant. The setup was monitored for six (6) weeks. Sampling was destructively performed on a weekly basis.…”

“…The choice of the method to use depends on the chemical, physical and biological properties of both contaminant and soil [1]. The physicochemical and thermal techniques have been found to be expensive and labourious [6]. Bioremediation (biological technique) has appeared as the most desirable method due to its simplicity, cost-effectiveness and ecofriendliness [2,3,5,4,8].…”

“…The experiment was designed as shown in Table 3. Each experiment was done in six (6) replicates because the experiment duration was six (6) weeks and a destructive sampling method was employed.…”

“…carbohydrate and proteins) which take only weeks to be degraded, while under extreme conditions (e.g. drought) it persists much longer [6].…”