Novel biological approaches for the removal of chlorophenolics [AOX] from bleach plant effluent

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Pentachlorophenol and spent engine oil degradation by Mucor ramosissimus

Pentachlorophenol (PCP) has been widely used for many years and belongs to the most toxic pollutants. Spent engine oils enter environment every day in many ways. Both of them cause great environmental concern. In the present work we focused on identifying metabolites of PCP biodegradation formed in the cultures of Mucor ramosissimus IM 6203 and optimizing medium composition to enhance PCP removal in the presence of engine oil acting as a carbon source. Pentachlorophenol (PCP) to tetrachlorohydroquinone (TCHQ) transformation was the most interesting transformation conducted by the tested strain. TCHQ was further transformed to 2,3,5,6-TCP and 2,3,4,6- TCP. Strain IM 6203 is also capable of PCP transformation to corresponding anisoles – pentachloromethoxybenzene (PCMB) and pentachloroethoxybenzene (PCEB). Characterization of enzymatic background involved in PCP to TCHQ transformation showed that TCHQ formation is catalyzed by inductive and cytochrome P-450 dependent enzymatic system. Experiments conducted on mineral medium allowed defining the optimal quantitative and qualitative medium make-up for PCP to TCHQ transformation. Biodegradation of PCP on the optimized synthetic medium X was more efficient than on rich Sabouraud medium. The tested strain is capable of growing in the presence of spent engine oil therefore we checked the ability of PCP transformation on optimized synthetic medium containing oil as a carbon source. The obtained results showed that PCP removal and TCHQ formation occurred were found to be the most efficient on the oil containing medium (OX medium). PCP removal and TCHQ formation after 240 h of culturing reached 1.19 mg/l and 0.89 mg/l, respectively. Additionally, 55.5% of oil introduced to the medium was removed during 10 days of the experiment. PCP biodegradation mechanisms used by Mucor species have not been sufficiently explained. The presented results point to the tested strain as an interesting model for the research on fungal PCP biodegradation in the areas highly contaminated with engine oil and for its future application in PCP and oils removal

The chemistry of ultrasonic degradation of organic compounds

The destruction of toxic organic molecules using advanced oxidation processes (AOPs) is a potent tool for pollution control and environmental protection. Ultrasound is a convenient and effective method of generating hydroxyl radicals which is the key oxidant in AOPs. This review describes the use of ultrasound and associated chemical reactions, with and without additives, as a powerful means of remediating water contaminated with organic pollutants. After a brief introduction to ultrasound and sonochemistry, their application for the oxidation of polycyclic aromatic hydrocarbons, phenol and substituted phenols is considered. Next is the decomposition of chlorinated phenols, and other chlorinated organics, then removal of recalcitrant smaller organic molecules. A discussion follows of recent work that has investigated the effects of initial concentration of substrates; the use of different ultrasonic frequencies; the inclusion of oxidising species, inorganic particles, or salts and their contribution to enhanced degradation. Finally, brief comments are made on the status of ultrasound as an AOP treatment

Xenobiotic biotransformation potential of Pseudomonas rhodesiae KCM-R5 and Bacillus subtilis KCM-RG5, tolerant to heavy metals and phenol derivatives

Two environmental bacterial isolates KCM-R5 and KCM-RG5 were selected from xenobiotic-polluted environment. KCM-R5 was identified as Pseudomonas rhodesiae and KCM-RG5 as Bacillus subtilis. KCM-R5 demonstrated tolerance to heavy metals and KCM-RG5 to heavy metals and phenol derivatives. Both strains were studied for xenobiotic biotransformation in order to contribute towards bioremediation of polluted environments. Pseudomonas rhodesiae KCM-R5 and Bacillus subtilis. KCM-RG5 possess unusual ability to utilize ortho-nitrophenol (o-NP) and 2,4- dichlorophenoxyacetic acid (2,4-D). o-NP and 2,4-D were added at concentration 30 mg/l. The possible indictive/inhibiting effect of Pb cations (40mg/l) was also studied. Pseudomonas rhodesiae KCM-R5 removed 86 % of o-NP and below 1% of 2,4-D. Bacillus subtilis KCM-RG5 eliminated 83% of o-NP andunder 1% of 2,4-D. Biotransformation effectiveness of o-NP reached 95-100% in contrast to 2,4-D where the effectiveness was just 15-20%. Cell morphological changes were registered during the biotransformation processes. The obtained results could contribute to manage bioremediation processes in polluted with heavy metals and phenol derivatives environments. . 1, . 2, . 2, .

Performance of Italian zeolitic tuffs and pozzolana in 2-chlorophenol removal from contaminated groundwater. Lab-scale experience

The physical and chemical properties of zeolites and the availability of localized deposits of naturally occurring zeolitized tuffs and pozzolana, make them desirable for and applicable to the remediation of contaminated groundwater. This paper documents the results of a laboratory study to test the capacity of native Italian zeolites to remove 2-chlorophenol (2-CP) from water. Italian zeolitic tuff and pozzolana were characterized in terms of their chemical and structural properties and of their adsorption capacities. Moreover, the experimental activity investigated their adsorption behaviour: time and pH dependence of the adsorption process was evaluated. The results of the time-dependence adsorption study under a constantly stirred condition showed that the adsorption increases with a longer contact time for all samples; the highest adsorption occurred at pH=8 divided by 8.5. Due to the good removal efficiencies obtained, a column test simulating the condition of an in situ permeable reactive barrier was carried out, in order to estimate the removal kinetics and the long-term behaviour. The removal efficiencies reached values higher than 90%, even if some long-term performance worsening occurred, due to the progressive exhaustion of the adsorption sites. These experiments demonstrate the capacity of naturally occurring zeolites to remove 2-CP from water and the opportunity to make economic use of these native deposits for in situ groundwater remediation

Biomass-supported catalysts on Desulfovibrio desulfuricans and Rhodobacter sphaeroides

A Rhodobacter sphaeroides-supported dried, ground palladium catalyst (‘‘Rs-Pd(0)’’) was compared with a Desulfovibrio desulfuricans-supported catalyst (‘‘Dd-Pd(0)’’)and with unsupported palladium metal particles made by reduction under H2 (‘‘Chem-Pd(0)’’). Cell surface-located clusters of Pd(0) nanoparticles were detected on both D. desulfuricans and R. sphaeroides but the size and location of deposits differed among comparably loaded preparations.\ud \ud These differences may underlie the observation of different activities of Dd-Pd(0) and Rs-Pd(0) when compared with respect to their ability to promote hydrogen release from hypophosphite and to catalyze chloride release from chlorinated aromatic compounds. Dd-Pd(0) was more effective in the reductive dehalogenation of polychlorinated biphenyls (PCBs), whereas Rs-Pd(0) was more effective in the initial dehalogenation of pentachlorophenol (PCP) although the rate of chloride release from PCP was comparable with both preparations after 2 h

Divergent roles of CprK paralogues from Desulfitobacterium hafniense in activating gene expression

Gene duplication and horizontal gene transfer play an important role in the evolution of prokaryotic genomes. We have investigated the role of three CprK paralogues from the cAMP receptor protein-fumarate and nitrate reduction regulator (CRP-FNR) family of transcriptional regulators that are encoded in the genome of Desulfitobacterium hafniense DCB-2 and possibly regulate expression of genes involved in the energy-conserving terminal reduction of organohalides (halorespiration). The results from in vivo and in vitro promoter probe assays show that two regulators (CprK1 and CprK2) have an at least partially overlapping effector specificity, with preference for ortho-chlorophenols, while meta-chlorophenols proved to be effectors for CprK4. The presence of a potential transposase-encoding gene in the vicinity of the cprK genes indicates that their redundancy is probably caused by mobile genetic elements. The CprK paralogues activated transcription from promoters containing a 14 bp inverted repeat (dehalobox) that closely resembles the FNR-box. We found a strong negative correlation between the rate of transcriptional activation and the number of nuclecitide changes from the optimal dehalobox sequence (TTAAT-N-4-ATTAA). Transcription was initiated by CprK4 from a promoter that is situated upstream of a gene encoding a methyl-accepting chemotaxis protein. This might be the first indication of taxis of an anaerobic bacterium to halogenated aromatic compounds

Хлорфенолы в органическом синтезе

Received: 17.08.2016; accepted: 11.10.2016; published: 01.12.2016.Поступило: 17.08.2016; приянято: 11.10.2016; опубликовано: 01.12.2016.This article reviews the alternatives for modifications of p-chlorophenols, p-chloroanisoles with the formation of C-C, C-N, C-S and C-B bonds. It is worth noting the high fundamental as well as practical importance of these reactions due to the availability and cheapness of initial chlorine substituted derivatives of phenol.В данном обзоре рассмотрены варианты модификаций п-хлорфенолов и п-хлоранизолов с образованием связей C-C, C-N, C-S и C-B. Стоит отметить высокую не только фундаментальную, но и практическую значимость данных реакций, ввиду доступности и дешевизны исходных хлорзамещенных производных фенола

Polysaccharide Ecocomposite Materials: Materials: Synthesis, Characterization and Application for Removal of Pollutants and Bacteria

A novel, simple and totally recyclable method has been developed for the synthesis of nontoxic, biocompatible and biodegradable composite materials from cellulose and chitosan. In this method, [BMIm+Cl-], an ionic liquid (IL), was used as a solvent to dissolve and synthesize the [CEL+CS] composite materials. Since the IL can be removed from the materials by washing them with water, and recovered from the washed solution, the method is totally recyclable. XRD, FTIR, NIR and SEM were used to characterize the materials and to confirm that CEL and CS were successfully regenerated by the method without any chemical transformation. More importantly, we have successfully demonstrated that [CEL+CS] material can serve as an effective adsorbent for removal of various endocrine disruptors including polychlorophenols and bisphenol A. This is because the composites have combined advantages of their components, namely superior chemical stability and mechanical stability (from CEL) and excellent adsorption capability for pollutants (from CS)

Investigation of taste tainting in salmon flesh in the Ribble catchment

This report presents the findings of the first phase of an investigation into the cause(s) of taints in salmonid fish in the River Ribble, commissioned by the North West Region of the Environment Agency. There have been reports of tainting in fish taken from both the estuary and the freshwater river for many years, but the contaminants involved and their source and transport pathway are unknown. Tainting by phenols has been of specific concern in the past. The work programme comprised: examination of tainting reports; collection of salmonids; their submission for taste testing; literature review; analysis of fish flesh using gas chromatography-mass spectrometry (GCMS) and analysis of river bed sediments. From enquiries, three common descriptors of the 'taint' were identified: disinfectanty; diesely; and muddy. The incidence of taints appears transient/irregular and may therefore relate to the incidence of discharges and specific threshold concentrations of pollutants. The literature review showed that a wide range of organic compounds including many industrial chemicals, and others which are naturally occurring, can taint fish flesh. Taste testing confirmed the presence of tainted salmon and trout in the Ribbie Catchment. It identified a low incidence of 'untainted' fish but demonstrated the 'taint' to be not specific to one tainting substance. Differences were found both between the species and fish from different parts of the catchment. Overall, most fish exhibited an unpleasant flavour, though this may have been influenced to some extent by the fact that most were sexually mature. The worst tainting was found in trout from the river Calder: a soapy/chemical aftertaste. An unpleasant earthy/musty flavour distinguished the salmon from the trout. Phenol was shown to have been a minor issue during the present study, whilst no hydrocarbon taints were identified. Examination of tissue from the eight salmon exhibiting the worst taints revealed the presence of aromatic hydrocarbons, but no phenolic compounds. Other notable substances present in the fish were siioxanes and benzophenone. Data from sediment analysis is presented which shows the main compounds present to be aromatic and polyaromatic hydrocarbons, that concentrations at two locations R. Darwen and R. Calder were significantly higher than at other sites, and that some phenolic compounds were detected at low levels. A paucity of fish flesh taste descriptors linked to specific compounds prevented an obvious correlation to be made between the tastes observed and the organic compounds detected. Descriptors frequently used by the taste testing panel (e.g. earthy, musty, astringency, chemical) cannot be linked to any of the compounds identified in the tissue analyses. No taste information was available from the literature on siioxanes. Aromatic hydrocarbons though present in tissue and sediments were not identified as tainting