Microbial Bioremediation of Petroleum Hydrocarbon– Contaminated Marine Environments

Petroleum pollution has become a serious environmental problem, which can cause harmful damage to the environment and human health. This pollutant is introduced into the environment from both natural and anthropogenic sources. Various physicochemical and biological treatments were developed for the cleanup of contaminated environments. However, bioremediation is based on the metabolic capabilities of microorganisms, and it is considered as the most basic and reliable way to eliminate contaminants, particularly petroleum and its recalcitrant compounds. It is more effective alternative comparing to classical remediation techniques. A high diversity of potential hydrocarbon degrader’s microorganisms was reported, and bacteria constitute the most abundant group, which has been well studied for hydrocarbon degradation. Several bioremediation approaches through bioaugmentation or/and biostimulation have been successfully applied. The interest on the optimizing of different parameters to achieve successful bioremediation technologies has been increased. In this chapter, we summarize the diversity and the hydrocarbon degradation potential of microorganism involved in the remediation of contaminated environments. We also present an overview of the efficient bioremediation strategies used for the decontamination of polluted marine environments

Innovative Research Approaches to Cope with Water Security in Africa

To achieve a water\u2010secure world, water management should be approached from a multidimensional and integrative perspective, addressing the water\u2010related issues of health, household supply, economics, the environment, and resilience to water\u2010related and climate change hazards. Although water security has significantly improved since 2000 in Africa, there are still vast inequalities in access to water suitable in terms of quantity and quality, especially in rural areas. To achieve water\u2010related sustainable development of African economies, a broad scope of innovative technological and management solutions is required, involving governments, research institutions, private sector parties, and civil society. This special series, composed of 8 papers, illustrates a selection of the most relevant results achieved by the 7 research projects selected and financed by the European Union under 2 dedicated Horizon 2020 calls in 2015: Water\u20105b\u20102015 \u201cA coordination platform\u201d and Water\u20105c\u20102015 \u201cDevelopment of water supply and sanitation technology, systems and tools, and/or methodologies.\u201d The innovations presented in this special series include both technological advancements and w'ater management approaches, given that the development of water\u2010related technologies in developing countries needs to be integrated into water management strategies and economic instruments. This special series aims to help policy makers take informed decisions on how to implement innovative approaches to increase water security in African countries

Genomic characterization of a polyvalent hydrocarbonoclastic bacterium Pseudomonas sp. strain BUN14

Bioremediation offers a viable alternative for the reduction of contaminants from the environment, particularly petroleum and its recalcitrant derivatives. In this study, the ability of a strain of Pseudomonas BUN14 to degrade crude oil, pristane and dioxin compounds, and to produce biosurfactants, was investigated. BUN14 is a halotolerant strain isolated from polluted sediment recovered from the refinery harbor on the Bizerte coast, north Tunisia and capable of producing surfactants. The strain BUN14 was assembled into 22 contigs of 4,898,053 bp with a mean GC content of 62.4%. Whole genome phylogeny and comparative genome analyses showed that strain BUN14 could be affiliated with two validly described Pseudomonas Type Strains, P. kunmingensis DSM 25974T and P. chloritidismutans AW-1T. The current study, however, revealed that the two Type Strains are probably conspecific and, given the priority of the latter, we proposed that P. kunmingensis DSM 25974 is a heteronym of P. chloritidismutans AW-1T. Using GC-FID analysis, we determined that BUN14 was able to use a range of hydrocarbons (crude oil, pristane, dibenzofuran, dibenzothiophene, naphthalene) as a sole carbon source. Genome analysis of BUN14 revealed the presence of a large repertoire of proteins (154) related to xenobiotic biodegradation and metabolism. Thus, 44 proteins were linked to the pathways for complete degradation of benzoate and naphthalene. The annotation of conserved functional domains led to the detection of putative genes encoding enzymes of the rhamnolipid biosynthesis pathway. Overall, the polyvalent hydrocarbon degradation capacity of BUN14 makes it a promising candidate for application in the bioremediation of polluted saline environments

The genome of Alcaligenes aquatilis strain BU33N: Insights into hydrocarbon degradation capacity

Environmental contamination with hydrocarbons though natural and anthropogenic activities is a serious threat to biodiversity and human health. Microbial bioremediation is considered as the effective means of treating such contamination. This study describes a biosurfactant producing bacterium capable of utilizing crude oil and various hydrocarbons as the sole carbon source. Strain BU33N was isolated from hydrocarbon polluted sediments from the Bizerte coast (northern Tunisia) and was identified as Alcaligenes aquatilis on the basis of 16S rRNA gene sequence analysis. When grown on crude oil and phenanthrene as sole carbon and energy sources, isolate BU33N was able to degrade ~86%, ~56% and 70% of TERHc, n-alkanes and phenanthrene, respectively. The draft genome sequence of the A. aquatilis strain BU33N was assembled into one scaffold of 3,838,299 bp (G+C content of 56.1%). Annotation of the BU33N genome resulted in 3,506 protein-coding genes and 56 rRNA genes. A large repertoire of genes related to the metabolism of aromatic compounds including genes encoding enzymes involved in the complete degradation of benzoate were identified. Also genes associated with resistance to heavy metals such as copper tolerance and cobalt-zinc-cadmium resistance were identified in BU33N. This work provides insight into the genomic basis of biodegradation capabilities and bioremediation/detoxification potential of A. aquatilis BU33N

Pseudomonas rhizophila S211, a New Plant Growth-Promoting Rhizobacterium with Potential in Pesticide-Bioremediation

A number of Pseudomonas strains function as inoculants for biocontrol, biofertilization, and phytostimulation, avoiding the use of pesticides and chemical fertilizers. Here, we present a new metabolically versatile plant growth-promoting rhizobacterium, Pseudomonas rhizophila S211, isolated from a pesticide contaminated artichoke field that shows biofertilization, biocontrol and bioremediation potentialities. The S211 genome was sequenced, annotated and key genomic elements related to plant growth promotion and biosurfactant (BS) synthesis were elucidated. S211 genome comprises 5,948,515 bp with 60.4% G+C content, 5306 coding genes and 215 RNA genes. The genome sequence analysis confirmed the presence of genes involved in plant-growth promoting and remediation activities such as the synthesis of ACC deaminase, putative dioxygenases, auxin, pyroverdin, exopolysaccharide levan and rhamnolipid BS. BS production by P. rhizophila S211 grown on olive mill wastewater based media was effectively optimized using a central-composite experimental design and response surface methodology (RSM). The optimum conditions for maximum BS production yield (720.80 ± 55.90 mg/L) were: 0.5% (v/v) inoculum size, 15% (v/v) olive oil mill wastewater (OMWW) and 40◦C incubation temperature at pH 6.0 for 8 days incubation period. Biochemical and structural characterization of S211 BS by chromatography and spectroscopy studies suggested the glycolipid nature of the BS. P. rhizophila rhamnolipid was stable over a wide range of temperature (40–90◦C), pH (6–10), and salt concentration (up to 300mM NaCl). Due to its low-cost production, emulsification activities and high performance in solubilization enhancement of chemical pesticides, the indigenous BS-producing PGPR S211 could be used as a promising agent for environmental bioremediation of pesticide-contaminated agricultural soils

Does CEO emotional bias affect performance?

This article is focused on tackling the issue of the impact of the bank CEO’s emotional bias on the Tunisian banks’ performance level while accounting for the mediating role of the control systems. In this regard, an empirical study has been set up through a questionnaire undertaken as an appropriately fit data collection method administered to a sample of 100 CEOs of Tunisian banks. Actually, the present research is intended to help in reflecting an original approach, since it serves to highlight the behavioral aspects’ crucial role in explaining the performance level within the framework of the organizational architecture theory. To the best of our knowledge, this work represents a pioneering study that deals with exploring such a research area within the Tunisian context. Indeed, the achieved results reveal with no doubt that the behavioral dimension constitutes a central aspect in the organizational architecture as it helps greatly in reflecting the intermingling of the incentive aspect with the evaluation system with respect to the accounts manager

Chemical and Biological Investigation of Organic Wastes of Frying Oils and Beef Fats: Valorization for Biodiesel Production

The present study investigates the different approaches of biodiesel production by exploiting low cost feedstocks such as organic wastes of frying oils (WFO) and wastes of beef fats (WBF). The aim was to compare not only two different sources of waste raw materials but also different approaches of biodiesel production. Biodiesel which refers to fatty acid methyl esters (FAME) was produced by both chemical and enzymatic transesterification. The characterization of the biodiesel produced by both approaches was performed according to the European standard EN 14214. The results showed that the biological method gave a richer FAME biodiesel through the catalysis of whole-cell lipase. However, for the chemical method, better biodiesel physicochemical properties were observed for the two raw materials. Therefore, it would be interesting to compromise by optimizing the biological biodiesel production approach in order to obtain a better quality in coherence with EN 14214 requirements

Analysis of inorganic chloramines in water

International audienceThis article describes the state of the art of the methods used for analysis of inorganic chloramines in water. After we introduce the physicochemical properties, the use and the toxicity of inorganic chloramines, we describe methods with little or no specificity (e.g., colorimetry, titrimetry and amperometry) and the chemical reagents used in these methods. We also introduce methods involving more specific techniques (e.g., high-performance liquid chromatography and mass spectrometry). We compare the performances of all these methods in terms of specificity, selectivity, limits of quantitation, ease of operation and possibility of automation. © 2012 Elsevier Ltd

Estrone direct photolysis: by-product identification using LC-Q-TOF.

International audienceThe identification of degradation products generated upon photolysis of estrone (E1), a natural estrogenic hormone, under simulated UV irradiation conditions was addressed by the use of LC-Q-TOF mass spectrometry. The structures of the main degradation products were elucidated, demonstrating how the use of model molecules 5,6,7,8-tetrahydro-2-naphtol (THN), 2-methylcyclopentanone (MCP), labeled molecule estrone D(4) (E1-D(4)), the investigation of the fragmentation pathways of the parent E1, the concurrent use of CID and exact mass measurements permit the characterization of structural modifications induced by photodegradation processes. In the present study, we identified nine major by-products of which seven photoproducts correspond to E1H(+) modified in positions other than the C-2, C-4 and C-16 of E1. Most of them showed one to three additional hydroxylations preferentially located on the aromatic ring of the parent E1, which confirms that these products may present environmental risk. Applications to real water samples have been conducted to extend the validity of the present study to environmental samples. © 2011 Elsevier Lt