Biodegradation Of Phenolic Compounds Research Articles

Changes of microbial community structures and functional genes during biodegradation of phenolic compounds under high salt condition

The changes of microbial community structures and functional genes during the biodegradation of single phenol and phenol plus p-cresol under high salt condition were explored. It was found that the phenol-fed system (PFS) exhibited stronger degrading abilities and more stable biomass than that of the phenol plus p-cresol-fed system (PCFS). The microbial community structures were revealed by a modern DNA fingerprint technique, ribosomal intergenic spacer analysis (RISA). The results indicated that the microbial community of PFS changed obviously when gradually increased phenol concentration, while PCFS showed a little change. 16S rRNA sequence analysis of the major bands showed that Alcanivorax sp. genus was predominant species during phenolic compounds degradation. Furthermore, amplified functional DNA restriction analysis (AFDRA) on phenol hydroxylase genes showed that the fingerprints were substantially different in the two systems, and the fingerprints were not the same during the different operational periods.

Biodegradation of phenolic compounds from coking wastewater by immobilized white rot fungus Phanerochaete chrysosporium

A white rot fungus Phanerochaete chrysosporium, immobilized with the wood chips of Italian poplar, was employed for biodegradation of phenolic compounds in coking wastewater. The immobilized fungus, dried by vacuum freeze desiccator, was kept high activity after a 9-month preservation and easy to be activated and domesticated. The removal rates of phenolic compounds and COD by immobilized fungus were 87.05% and 72.09% in 6 days, which were obviously higher than that by free fungus. For phenolic compounds biodegradation, a pH ranging from 4.0 to 6.0 and a temperature ranging from 28 °C to 37 °C create suitable conditions, and optimum 5.0 and 35 °C, respectively. The optimum removal rate of phenolic compounds was over 84% and COD was 80% in 3 days. And the biodegradation of phenolic compounds followed the first-order kinetics. It is an efficient and convenient method for coking wastewater treatment.

Relationship between cultivation mode of white rot fungi and their efficiency for olive oil mill wastewaters treatment

Four white rot fungi (WRF) strains, Phanerochaete chrysosporium , Trametes versicolor , Coriolopsis polyzona and Pycnoporus coccineus , were tested for efficiency of treatment of Olive Oil mill wastewaters (OOMW) in relation with their cultivation mode, i.e. under the form of free mycelium, mycelium immobilized in alginate beads and solid state cultivation on Petri dishes. Study of biodegradation of phenolic compounds, chemical oxygen demand (COD) decrease and decolourisation of OOMW have shown that Coriolopsis polyzona and Pycnoporus coccineus degradation performances were apparently only slightly affected by the cell cultivation procedures experienced here. In contrast, Phanerochaete chrysosporium and Trametes versicolor showed respectively marked preferences for solid state and alginate immobilisation procedures. Both mono and polyphenolics were reduced to different extent during incubation depending on the strain, as shown by gel filtration analysis. Final pH obtained after fungal treatment of the OOMW based medium (initial pH of 5.0) was measured in order to evaluate the possibility of releasing friendly the treated wastewater in the environment. Laboratory studies as reported here may be useful for orienting the choice of a strain for treating pollution by OOMW in a particular real situation.

Biodegradation of phenolic compounds by the mixed culture of Arthrobacter sp. and Candida sp. under high salt conditions

Biodegradation of phenolic compounds by the mixed culture of Arthrobacter sp. and Candida sp. under high salt conditions

Extension of the anaerobic digestion model No. 1 (ADM1) to include phenolic compounds biodegradation processes for the simulation of anaerobic co-digestion of olive mill wastes at thermophilic temperature

This paper describes for the first time the extension of the anaerobic digestion model No. 1 (ADM1) to handle and simulate the anaerobic degradation processes of phenol compounds and homologues in olive mill wastewater (OMW) and olive mill solid waste (OMSW) at thermophilic temperature (55 °C). The general structure of the ADM1 was not changed except for the modifications related to the inclusion of phenolic compounds degradation processes into acetate and further into methane and CO 2. The effect of soluble phenolic compounds upon pH was taken into account in the pH simulation equations. The inhibitory effect of phenolic compounds on the fermenting process and methanogenic sub-populations was accounted for by the use of non-competitive inhibition functions. The most sensitive and new phenolic parameters were calibrated and validated using experimental data from our previous study dealing with the thermophilic anaerobic co-digestion of OMW with OMSW in semi-continuous tubular digesters. The simulation results indicated that the extended ADM1 was able to predict with reasonable accuracy effluent phenol concentrations and gas flow rates and effluent pH of various influent concentrations digested at hydraulic retention times (HRTs) of 36 and 24 days.

Inductive and resonance effects of substituents adjust the microalgal biodegradation of toxical phenolic compounds

The type and the position of the substituent in the phenolic ring, the bond dissociation energy and the exogenously supplied carbon source as well as the inductive and resonance effect phenomena of the substituents adjust the biodegradability of the phenolic compounds. The comparative biodegradation study of mono-nitrophenols (electron acceptors) and mono-methylphenols (electron donors) revealed that it is a completely photoregulated process. The closer the donor group (OH −) of the phenolic ring is to the acceptor group (NO 2 −), the higher the biodegradation values are (2-nitrophenol > 3-nitrophenol > 4-nitrophenol); the further the donor group (OH −) of the phenolic compound is from the second donor group (CH 3 +), the higher the biodegradation values are (2-methylphenol < 3-methylphenol < 4-methylphenol). However, there are compounds without a specific role of acceptor or donor such as mono-iodophenols, where a type of counteraction between the inductive and resonance effect determines the behavior of the substituent. This fact combined with the presence of the hydroxyl group in the phenolic ring gave the observed stabilization in the biodegradation results of mono-iodophenols (2-iodophenol ≈ 3-iodophenol ≈ 4-iodophenol).

Bioenergetic strategy of microalgae for the biodegradation of phenolic compounds—Exogenously supplied energy and carbon sources adjust the level of biodegradation

The biodegradation of phenolic compounds by microalgae seems to be not a simple feature of a particular organism, but mostly a bioenergetic process depending on the growth conditions, especially on the exogenously supplied energy (carbon and light) sources. By using chlorophyll fluorescence induction measurements to estimate the molecular structure and function of the photosynthetic apparatus and therefore the tolerance/sensitivity of microalgae incubated with phenols, it can be assumed that, at least in low concentrations, phenol have no toxic effects on the cultures and can be used as alternative carbon source in them. Halophenols (chlorophenols, bromophenols and iodophenols) are quite toxic for the microalgal cultures. In halophenols the first step of the biodegradation is the split of the halogen substituent (dehalogenation). This is strongly determined by the bond dissociation energy of the corresponding substituent and therefore the energetic requirement for the biodegradation of halophenols increases following the sequence: iodophenol<bromophenol<chlorophenol. Additionally, the meta-position of the halogen on the phenol ring needs more energy than the ortho- and the para-one. These are possible explanations of the fact that the biodegradation of halophenols needs additional energy sources that can be exogenously supplied as organic carbon (glucose) or inorganic carbon (CO(2)).

Simultaneous biodegradation of a phenol and 3,4-dimethylphenol mixture under denitrifying conditions

Denitrification is a feasible alternative for the treatment of phenolic bearing-wastewaters. The aim of this study was to evaluate the biodegradability of phenolic compounds, as the only carbon and energy source in batch and continuous experiments, using nitrate as a final electron acceptor. Experiments in a continuous upward anaerobic sludge bed reactor demonstrated the possibility of biodegrading a mixture of phenol and 3,4-dimethylphenol at organic loads of 251.6 and 39.5 mg/L-d, respectively, at a COD/NO3(-)-N ratio of 2.57. A nitrogen production efficiency of 86% was obtained according to the nitrate consumption. GC-MS analyses demonstrated that m-cresol was an intermediate of 3,4-dimethylphenol degradation in batch conditions, and had an inhibitory effect on phenol degradation.

Fermentative decolorization of olive mill wastewater by Lactobacillus plantarum

The effects of Lactobacillus plantarum growth on reductive decolorization and biodegradation of phenolic compounds were evaluated. L. plantarum growth on fresh Olive Mill Wastewaters (OMW) for 6 days produced an increase in the number of viable cells and decrease of pH due to the production of lactic acid. The growth of L. plantarum led to the depolymerization of phenolic compounds of high molecular weight, with a resultant decolorization of fresh OMW and significant reduction of total phenols, in proportion to the dilution of OMW. Approximately 58% of the color, 55% of the chemical oxygen demand (COD) and 46% of the phenolic compounds were removed when OMW was diluted ten times. During fermentation COD and color removal increased while the number of viable cells remained constant because L. plantarum growth resulted in an increase in total suspended solid (TSS) corresponding to phenolic compounds adsorbed on cells. The removal of phenolic compounds was associated with depolymerization, their partial adsorption on the cells and biodegradation of certain simple phenolic compounds. Moreover, L. plantarum produced an inverse reaction of auto-oxidation in the oxidized phenolic compounds contained in black stored OMW by reductive depolymerization, while at the same time leading to decolorization.

Decolorization of fresh and stored-black olive mill wastewaters by Geotrichum candidum

Decolorization of phenolic compounds contained in fresh and stored-black olive mill wastewaters (OMW) by Geotrichum candidum in an aerated batch bioreactor was investigated. During storage of OMW, autooxidation and subsequent polymerization of phenolic compounds and tannins, gives rise to darkly coloured phenolic compounds which are not readily biodegradable. G. candidum growth on fresh OMW decreased pH and reduced COD by 50% removal during the first 3 days and subsequently by a further 15%. In contrast, 75% of the colour was removed during the last 3 days of culture because G. candidum hydrolyzed phenolic compounds with high molecular weight and removed many simple phenolic compounds. G. candidum growth on the stored-black OMW was rapidly inhibited resulting in low reduction COD (25%) with no decolorization because phenol polymerization was amplified by the increased pH and oxygen. The addition of oxygen to enable G. candidum growth and biodegradation of phenolic compounds is critical in order to avoid the polymerization of phenolic compounds and tannins.

A novel application for Neurospora crassa: Progress from batch culture to a membrane bioreactor for the bioremediation of phenols

The capacity of a Neurospora crassa fungal system to produce oxidative enzymes, and their application in the biodegradation of phenolic compounds, was demonstrated in static and shaken non-immobilized batch cultures, and by capillary membrane-immobilized biofilms. Extracellular laccase activity was produced at 10–12 U/mL (800 U/g wet mass) in static flask cultures, and 1.5 U/mL (130 U/g wet mass) in shaken batch cultures, respectively, over 8–15 days. Polyphenol oxidase was shown to be produced as an intracellular enzyme, at levels of 374 U/g wet mass. The production of laccase in a capillary membrane bioreactor was sustained at a level of 10 U/mL of permeate (1080 U/g wet biomass), typically over 30–40 days. Two phenolic substrates, phenol and p-cresol, both common components of industrial effluent streams, were chosen as model pollutants for bioremediation studies using the N.crassa enzyme system. In flask cultures, 18 mg p-cresol and 23 mg phenol respectively were removed from 5 mM solutions/g wet biomass, over a 6 day period. Over the same time period, immobilized cultures were found to convert 10 mg p-cresol or 8 mg phenol/g biomass. The immobilized biomass in a continuous reactor was found to have the capacity to sustain this removal efficiency continuously for a 4-month period, whereas the batch liquid culture systems remained active for approximately 8–15 days, after which cultures were no longer viable. This is the first demonstration of the use of immobilized N.crassa biofilms and their continuous application for bioremediation of phenols.

Potential application of catalase-peroxidase from Comamonas terrigena N3H in the biodegradation of phenolic compounds.

Comamonas terrigena N3H is a gram-negative rod-shaped bacterium that was isolated from contaminated soil in Slovakia. This bacterium showed remarkable biodegradation properties. We investigated the expression and functioning of two catalase isozymes in this bacterium. The typical catalase could be induced by cadmium ions, whereas the catalase-peroxidase enzyme was constitutively expressed. Since C. terrigena lacks the key enzyme for complete degradation of phenols (phenolhydroxylase), we analysed the possible removal of phenol by the two catalases of this bacterium. Addition of phenol to the culture medium led to increased expression of the catalase-peroxidase. Applying oxidative stress prior to phenol administration markedly induced the expression of the typical catalase, irrespective of the nature of the added agent. Thus, the rate of phenol degradation is rather reduced under these conditions, while growth of the cells is not impaired. We concluded that phenol peroxidation in C. terrigena can be largely attributed to the action of a catalase-peroxidase. The potential application of this enzyme in the removal of phenol from the environment is discussed.

Determination of plasmid-encoded functions in Rhizobium leguminosarum biovar trifolii using proteome analysis of plasmid-cured derivatives.

We have used proteome analysis of derivatives of R. leguminosarum biovar trifolii strain ANU843, cured of indigenous plasmids by a direct selection system, to investigate plasmid-encoded functions. Under the conditions used, the plasmid-encoded gene products contributed to only a small proportion of the 2000 proteins visualised in the two-dimensional (2-D) protein map of strain ANU843. The level of synthesis of thirty-nine proteins was affected after curing of either plasmid a, c or e. The differences observed upon plasmid curing included: protein loss, up/down-regulation of specific proteins and novel synthesis of some proteins. This suggests that a complex interplay between the cured plasmid and the remaining replicons is occurring. Twenty-two proteins appeared to be absent in the cured strains and these presumably are encoded by plasmid genes. Of these, a small heat shock protein, a cold shock protein, a hypothetical YTFG-29.7 kDa protein, and the alpha and beta subunits of the electron transfer flavoprotein were identified by N-terminal microsequencing and predicted to be encoded by plasmid e. Four of the sequenced proteins putatively encoded on plasmid e and two encoded on plasmid c were novel. In addition, curing of plasmid e and c consistently decreased the levels of 3-isopropylmalate dehydratase and malate dehydrogenase, respectively, suggesting that levels of these proteins may be influenced by plasmid-encoded functions. A protein with homology to 4-oxalocrotonate tautomerase, which is involved in the biodegradation of phenolic compounds, was found to be newly synthesised in the strain cured of plasmid e. Proteome analysis provides a sensitive tool to examine the functional organisation of the Rhizobium genome and the global gene interactions which occur between the different replicons.

Biodegradation of phenolic compounds by an acclimated activated sludge and isolated bacteria

The degradation of a mixture of phenol, 4-chlorophenol (4CP), 2,4-dichlorophenol (24DCP) and 2,4,6-trichlorophenol (246TCP) by acclimated activated sludge and by isolated bacteria was studied. Activated sludge was acclimated for 70 days to 40 mg phenols/l then the microorganisms responsible for the CP degradation were isolated and identified. Four types of Gram-negative bacteria (Aeromonas sp., Pseudomonas sp. Flavomonas oryzihabitans, and Chryseomonas luteola) were identified. Also, two acid-fast bacilli with distinct glycolipid patterns were isolated. From their chemical composition and their growth characteristics, both isolates appeared to be mycobacteria closely related to Mycobacterium peregrinum. The degradation kinetics of each phenol by Aeromonas sp., Pseudomonas sp. Flavomonas oryzihabitans, Chryseomonas luteola and activated sludge were determined. The acclimated activated sludge degradation rates were from one to two orders of magnitude higher than those of pure strains when uptake rates were calculated in terms of the viable biomass (CFU). The specific substrate uptake rate for acclimated activated sludge varied between 8.2 and 15.8 × 10−7 mg/CFU·d (407-784 mg/gVSS·d). Aeromonas sp. had the highest specific substrate uptake rate of the pure strains, based on a VSS basis (33-57 mg/gVSS·d) but, in terms of viable biomass (5.0-15.6 × 10−8 mg/CFU·d), the Pseudomonas sp. rate was the highest. Specific substrate uptake rates were 1.8 mg chlorinated phenols/g VSS·d for unacclimated activated sludge.

Biodegradation of phenolic compounds by an acclimated activated sludge and isolated bacteria

The degradation of a mixture of phenol, 4-chlorophenol (4CP), 2,4-dichlorophenol (24DCP) and 2,4,6-trichlorophenol (246TCP) by acclimated activated sludge and by isolated bacteria was studied. Activated sludge was acclimated for 70 days to 40 mg phenols/1 then the microorganisms responsible for the CP degradation were isolated and identified. Four types of Gram-negative bacteria (Aeromonas sp., Pseudomonas sp. Flavomonas oryzihabitans, and Chryseomonas luteola) were identified. Also, two acid-fast bacilli with distinct glycolipid patterns were isolated. From their chemical composition and their growth characteristics, both isolates appeared to be mycobacteria closely related to Mycobacterium peregrinum. The degradation kinetics of each phenol by Aeromonas sp., Pseudomonas sp. Flavomonas oryzihabitans, Chrvseomonas luteola and activated sludge were determined. The acclimated activated sludge degradation rates were from one to two orders of magnitude higher than those of pure strains when uptake rates were calculated in terms of the viable biomass (CFU). The specific substrate uptake rate for acclimated activated sludge varied between 8.2 and 15.8 ß 10−7 mg/CFU·d (407-784 mg/BVSS·d). Aeromonas sp. had the highest specific substrate uptake rate of the pure strains, based on a VSS basis (33–57 mg/gVSS·d) but, in terms of viable biomass (5.0–15.6 × 10−8 mg/CFU·d), the Pseudomonas sp. rate was the highest. Specific substrate uptake rates were 1.8 mg chlorinated phenoWg VSS-d for unacclimated activated sludge.

Monitoring of Biodegradative Pseudomonas putida Strains in Aquatic Environments Using Molecular Techniques

Monitoring strategies were developed to track non–genetically engineered Pseudomonas putida strains in the open environment. The strain E1 was used for four years for the biodegradation of phenolic compounds in industrial wastewater in Polva, Estonia. In this study we used the strain E2 which is a non-carbenicillin-resistant variant of the strain E1. Both strains have a deletion of approximately 34 kb in the TOL plasmid pWW0 which served as a basis for discrimination from indigenous bacteria by molecular analyses. Other targets used for PCR and DNA hybridization were the xylE gene and a sequence located in the left-handed region of to the transposon Tn4652. In laboratory tests we demonstrated that two cells inoculated into 20 ml of river water could be detected against a background of more than 107 colony forming units (CFUs) by a combination of growth on selective media and molecular analysis. Using the same combination of methods in a deliberate release experiment, detection of the released strain was possible only to 32 h after release. It is assumed that the released strains did not survive in the aquatic ecosystem, mainly due to the high dilution rate. The combination of cultivation on selective media and molecular analyses proved useful for tracking Pseudomonas putida strain E2 in an aquatic environment.

Inoculation of microorganisms to enhance biodegradation of phenolic compounds in industrial wastewater: Isolation and identification of three-indigenous bacterial strains.

Six indigenous and six non-indigenous bacteria capable of degrading phenolic compounds in pure cultures were inoculated into industrial wastewater samples of Puerto Rico containing high and low concentrations of p-nitrophenol (PNP). While only one non-indigenous bacteria enhanced PNP degradation, all of the indigenous bacteria enhanced degradation of both high (20 μg/ml) and low (26 ng/ml) concentrations of PNP, suggesting that indigenous bacteria are more suitable for inoculation in the tropical environment of Puerto Rico. In this report we characterized three indigenous strains (Corynebacterium sp. strain Z-2, Pseudomonas putida strain GS, Acinetobacter sp. strain BR-1) capable of enhancing degradation of PNP in industrial wastewater. The three indigenous bacteria, however, were different from each other in their response to substrate concentration as well as in their rate and extent of PNP degradation.

Biodegradation of phenolic compounds by sulfate-reducing bacteria from contaminated sediments

The biodegradation of phenolic compounds under sulfate-reducing conditions was studied in sediments from northern Indiana. Phenol, p-cresol and 4-chlorophenol were selected as test substrates and added to sediment suspensions from four sites at an initial concentration of 10 mg/liter. Degradative abilities of the sediment microorganisms from the four sites could be related to previous exposure to phenolic pollution. Time to onset of biodegradation of p-cresol and phenol in sediment suspensions from a nonindustrialized site was approximately 70 and 100 days, respectively, in unacclimated cultures. In sediment slurries from three sites with a history of wastewater discharges containing phenolics, time to onset of biodegradation was 50-70 days for p-cresol and 50-70 days for phenol in unacclimated cultures. In acclimated cultures from all four sites, the length of the lag phase was reduced to 14-35 days for p-cresol and 25-60 days for phenol. Length of the biodegradative phase varied from 25 to 40 days for phenol and 10 to 50 days for p-cresol and was not markedly affected by acclimation. Substrate mineralization by sulfate-reducing bacteria was confirmed with radiotracer techniques using an acclimated sediment culture from one site. Addition of molybdate, a specific inhibitor of sulfate reduction, and bacterial cell inactivation inhibited sulfate reduction and substrate utilization. None of the sites exhibited the ability to degrade 4-chlorophenol, nor were acclimated phenol and p-cresol degrading cultures from a particular site able to cometabolize 4-chlorophenol.

Modeling steady-state methanogenic degradation of phenols in groundwater

Field and microcosm observations of methanogenic phenolic compound degradation indicate that Monod kinetics governs the substrate disappearance but overestimates the observed biomass. In this paper we present modeling results from an ongoing multidisciplinary study of methanogenic biodegradation of phenolic compounds in a sand and gravel aquifer contaminated by chemicals and wastes used in wood treatment. Field disappearance rates of four phenols match those determined in batch microcosm studies previously performed by E.M. Godsy and coworkers. The degradation process appears to be at steady-state because even after a sustained influx over several decades, the contaminants still are disappearing in transport downgradient. The existence of a steady-state degradation profile of each substrate together with a low biomass density in the aquifer indicate that the bacteria population is exhibiting no net growth. This may be due to the oligotrophic nature of the biomass population in which utilization and growth are approximately independent of concentration for most of the concentration range. Thus a constant growth rate should exist over much of the contaminated area which may in turn be balanced by an unusually high decay or maintenance rate due to hostile conditions or predation.

The effect of oxidative coloration on the methanogenic toxicity and anaerobic biodegradability of phenols

Phenolic compounds are often present in agricultural wastewater intended for anaerobic treatment. During industrial processing, storage or wastewater pretreatments, these compounds are susceptible to oxidative modifications leading to the formation of colored oxidized products. In this study, the role of the oxidative coloration on changing the methanogenic toxicity and anaerobic biodegradability of phenolic compounds was examined. Short exposures to air increased the methanogenic toxicity of monomeric phenols provided these compounds had neighboring hydroxyl groups, necessary for the coloration, and if their oxidized products lacked free carboxylic-acid groups. In contrast, a methanogenic toxic tannin, gallotannic acid (oligomeric), was detoxified by oxidative coloration. The extensive oxidation of a monomer, l-dopa, produced a dark-colored precipitate which was non-toxic. These results indicated that the initial products of the oxidation of monomers are toxic whereas highly polymerized products are non-toxic. The colorless phenolic compounds tested in this study were either partially or fully degraded (with the exception of catechol). The trihydroxyphenols were the most readily biodegradable compounds. The oxidized solutions of trihydroxyphenols were less biodegradable in proportion to their color.