Enriched Bacterial Consortium Research Articles

Metagenomics reveals mechanism of pyrene degradation by an enriched bacterial consortium from a coking site contaminated with PAHs

A bacterial consortium, termed WPB, was obtained from polycyclic aromatic hydrocarbons (PAHs) contaminated soil from a coking site. The consortium effectively degraded 100 mg L-1 pyrene by 94.8 % within 12 days. WPB was also able to degrade phenanthrene (98.3 %) and benzo[a]pyrene (24.6 %) in 12 days, while the individual isolates showed no PAHs degrading ability. Paracoccus sp. dominated the bacterial consortium (65.0-86.2 %) throughout the degradation process. Metagenomic sequencing reveals the proportion of sequences with xenobiotics biodegradation and metabolism increased throughout the degradation process indicating the great potential of WPB to degrade pollutants. The annotation of genes by metagenomic analysis help reconstruct the degradation pathways ("phthalate pathway" and "naphthalene degradation") and reveal how different bacteria contribute to the degradation process. Mycobacterium gilvum was found to carry nidAB genes that catalyze the first step of high-molecular-weight (HMW) PAHs in the degradation process despite Mycobacterium gilvum accounting for only 0.005-0.06 %. In addition, genomes of Paracoccus denitrificans and some other genera affiliated with Devosia, Pusillimonas caeni and Eoetvoesia caeni were successfully recovered and were found to carry genes responsible for the degradation of the intermediates of pyrene. These results enable further understanding of the metabolic patterns of pyrene-degrading consortia and provide direction for further cultivation and discovery of key players in complex microbial consortia.

Degradation of 1,2-dichloroethane in real polluted groundwater by using enriched bacterial consortia in aerobic and anaerobic laboratory-scale conditions

Degradation of 1,2-dichloroethane in real polluted groundwater by using enriched bacterial consortia in aerobic and anaerobic laboratory-scale conditions

Bioleaching of Heavy Metals from Printed Circuit Boards with an Acidophilic Iron-Oxidizing Microbial Consortium in Stirred Tank Reactors.

In this study, bioleaching was carried out for the recovery of metals (copper, zinc, tin, lead, gold and silver) from printed circuit boards residues (PCBs), one of the most important wastes from electrical and electronic equipment, using an acidophilic iron-oxidizing bacterial consortium enriched with minerals from a gold mine in the Arequipa region, Peru. High-throughput sequencing and analysis of the 16S rRNA biomarker revealed that this consortium was predominantly composed of Tissierella, Acidiphilium and Leptospirillum bacteria, from which the latter is known to grow by chemolithotrophy through iron oxidation. After the enrichment process, the acidophilic iron-oxidizing consortium was first tested for its tolerance to different PCBs concentrations, showing best growth up to 10 g/L of PCBs and a tolerance index of 0.383. Based on these results, the bioleaching efficiency of the consortium was investigated for 10 g/L of PCBs in stirred tank reactors coupled to an aeration system, for 18 days. High bioleaching efficiencies were achieved for copper and zinc (69% and 91%, respectively), indicating that these two metals can be easily extracted in this leaching system. Lower extraction efficiencies were achieved for tin (16%) and gold (28%), while for lead and silver only a residual recovery (<0.25%) was detected. These results indicate that the enriched bacterial consortium originating from the Arequipa region, Peru, has a high capacity to recover different metals of economic importance.

Unravelling the genetic and functional diversity of dominant bacterial communities involved in manure co-composting bioremediation of complex crude oil waste sludge

The present study aimed to characterize the bacterial community and functional diversity in co-composting microcosms of crude oil waste sludge amended with different animal manures, and to evaluate the scope for biostimulation based in situ bioremediation. Gas chromatography–mass spectrometry (GC–MS) analyses revealed enhanced attenuation (>90%) of the total polyaromatic hydrocarbons (PAHs); the manure amendments significantly enhancing (up to 30%) the degradation of high molecular weight (HMW) PAHs. Microbial community analysis showed the dominance (>99% of total sequences) of sequences affiliated to phyla Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. The core genera enriched were related to hydrocarbon metabolism (Pseudomonas, Delftia, Methylobacterium, Dietzia, Bacillus, Propionibacterium, Bradyrhizobium, Streptomyces, Achromobacter, Microbacterium and Sphingomonas). However, manure-treated samples exhibited high number and heterogeneity of unique operational taxonomic units (OTUs) with enrichment of additional hydrocarbon-degrading bacterial taxa (Proteiniphilum, unclassified Micrococcales, unclassified Lachnospiraceae, Sphingobium and Stenotrophomonas). Thirty-three culturable hydrocarbon-degrading microbes were isolated from the co-composting microcosms and mainly classified into Burkholderia, Sanguibacter, Pseudomonas, Bacillus, Rhodococcus, Lysinibacillus, Microbacterium, Brevibacterium, Geobacillus, Micrococcus, Arthrobacter, Cellulimicrobacterium, Streptomyces Dietzia,etc,. that was additionally affirmed with the presence of catechol 2,3-dioxygenase gene. Finally, enhanced in situ degradation of total (49%), LMW (>75%) and HMW PAHs (>35%) was achieved with an enriched bacterial consortium of these microbes. Overall, these findings suggests that co-composting treatment of crude oil sludge with animal manures selects for intrinsically diverse bacterial community, that could be a driving force behind accelerated bioremediation, and can be exploited for engineered remediation processes.

Reconstructing polyaromatic hydrocarbons degrading pathways in the enriched bacterial consortium and their biosurfactants characterization

Due to substantial metabolic burden and low carbon fluxes, a single microorganism cannot utilize multiple classes of hydrocarbons typically found in the polluted environment. A microbial consortium comprising biosurfactants producing strains and hydrocarbon degradative strains could have promising bioremediation capabilities. To address this question, bacteria from non-contaminated soil were enriched in a medium containing polyaromatic hydrocarbons. The metabolic potential and pathways of PAHs degrading bacterial consortia (CON-PAH) that drive energy and carbon from PAHs assimilation were elucidated by metagenomic analysis. CON-PAH degrade more than 90% of PAHs (naphthalene, phenanthrene, and pyrene) with concomitant biosurfactants production. Tween-20 and glucose as a co-substrate suppress the PAHs degradation. Six high-quality metagenome-assembled genomes (MAGs) were assembled with an estimated size of 3.8–6.5 Mb from metagenomic data of CON-PAH. The draft genome of Deliftia tsuruhatensis and Pseudomonas putida contain the entire benzoate and near-complete naphthalene and phenanthrene degradation pathways. For the first time, we reconstruct PAH degrading pathway in D. tsuruhatensis sp. The metagenomic reconstruction of bins indicates the cross-feeding of bacteria within the consortium and suggests that complete PAH degradation pathways may not be obligatory for individual bacteria in the consortium. Biosurfactants structure elucidation via LC/MS showed lipopeptide containing the heptapeptides with different lipid moieties. This work will deepen our understanding of the metabolic capacity of microbial communities and provide new ideas for the engineering of artificial microbial consortia. • Minimal medium containing hydrophobic compounds is a practical approach for isolating biosurfactants and biodegradative bacteria. • Non-contaminated soil bacteria have the intrinsic ability to degrade polyaromatic hydrocarbons. • Reconstruction of near complete PAHs degrading pathway in Deliftia tsuruhatensis and Pseudomonas putida sp. • Tween-20 and glucose as a co-substrate suppress the PAHs degradation.

Biodegradation of binary mixtures of octane with benzene, toluene, ethylbenzene or xylene (BTEX): insights on the potential of Burkholderia, Pseudomonas and Cupriavidus isolates

The contamination of the environment by crude oil and its by-products, mainly composed of aliphatic and aromatic hydrocarbons, is a widespread problem. Biodegradation by bacteria is one of the processes responsible for the removal of these pollutants. This study was conducted to determine the abilities of Burkholderia sp. B5, Cupriavidus sp. B1, Pseudomonas sp. T1, and another Cupriavidus sp. X5 to degrade binary mixtures of octane (representing aliphatic hydrocarbons) with benzene, toluene, ethylbenzene, or xylene (BTEX as aromatic hydrocarbons) at a final concentration of 100ppm under aerobic conditions. These strains were isolated from an enriched bacterial consortium (Yabase or Y consortium) that prefer to degrade aromatic hydrocarbon over aliphatic hydrocarbons. We found that B5 degraded all BTEX compounds more rapidly than octane. In contrast, B1, T1 and X5 utilized more of octane over BTX compounds. B5 also preferred to use benzene over octane with varying concentrations of up to 200mg/l. B5 possesses alkane hydroxylase (alkB) and catechol 2,3-dioxygenase (C23D) genes, which are responsible for the degradation of alkanes and aromatic hydrocarbons, respectively. This study strongly supports our notion that Burkholderia played a key role in the preferential degradation of aromatic hydrocarbons over aliphatic hydrocarbons in the previously characterized Y consortium. The preferential degradation of more toxic aromatic hydrocarbons over aliphatics is crucial in risk-based bioremediation.

Metagenomic analysis of a keratin-degrading bacterial consortium provides insight into the keratinolytic mechanisms

Keratin is an insoluble fibrous protein from natural environments, which can be recycled to value-added products by keratinolytic microorganisms. A microbial consortium with efficient keratinolytic activity was previously enriched from soil, but the genetic basis behind its remarkable degradation properties was not investigated yet. To identify the metabolic pathways involved in keratinolysis and clarify the observed synergy among community members, shotgun metagenomic sequencing was performed to reconstruct metagenome-assembled genomes. More than 90% generaof the enriched bacterial consortium were affiliated to Chryseobacterium, Stenotrophomonas, and Pseudomonas. Metabolic potential and putative keratinases were predicted from the metagenomic annotation, providing the genetic basis of keratin degradation. Furthermore, metabolic pathways associated with keratinolytic processes such as amino acid metabolism, disulfide reduction and urea cycle were investigated from seven high-quality metagenome-assembled genomes, revealing the potential metabolic cooperation related to keratin degradation. This knowledge deepens the understanding of microbial keratinolytic mechanisms at play in a complex community, pinpointing the significance of synergistic interactions, which could be further used to optimize industrial keratin degradation processes.

Chloramphenicol biodegradation by enriched bacterial consortia and isolated strain Sphingomonas sp. CL5.1: The reconstruction of a novel biodegradation pathway

Figuring out the comprehensive metabolic mechanism of chloramphenicol (CAP) is critical to improving CAP removal in the bioremediation process. In this study, CAP biodegradation by six consortia and isolated Sphingomonas sp. CL5.1 were systematically investigated using the combination of high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, second-generation, and third-generation sequencing technologies. The CAP-degrading capability of six consortia was enhanced while CAP mineralization rate declined after long-term enrichment. The microbial community structures of six consortia were all simplified with 69%-82% decline in species richness after continuous passages for one year. The core genera of consortia CL and CH included Sphingomonas, Cupriavidus, Burkholderia, Chryseobacterium, and Pigmentiphaga, which accounted for over 98% of the total population. Sphingomonas was discovered as a new CAP degrader that could subsist on CAP as the sole carbon, nitrogen, and energy sources. Sphingomonas sp. CL5.1 was able to completely remove 120mg/L CAP within 48 hours with a mineralization rate of 50.4%. The presence of acetate or nitrite could inhibit CAP metabolization by strain CL5.1. Four CAP metabolic pathways were constructed, including modification of the C3 hydroxyl group of CAP via acetylation, oxidization, dehydration and the bond cleavage between C1 and C2. C3 hydroxyl group dehydration and C1-C2 bond-cleavage were first reported regarding to CAP biotransformation. Strain CL5.1 played a core role in the consortia and was responsible for C3 hydroxyl oxidation, C3 dehydration, and C1-C2 bond cleavage. Genomic information of strain CL5.1 revealed the further mineralization pathways of downstream product p-nitrobenzoic acid via ortho- and meta-cleavage.

High-efficiency biodegradation of chloramphenicol by enriched bacterial consortia: Kinetics study and bacterial community characterization

The risk of environmental pollution caused by chloramphenicol has necessitated special attention. Biodegradation has tremendous potential for chloramphenicol removal in the environment. Six chloramphenicol-degrading consortia were acclimated under different culture conditions to investigate their chloramphenicol biodegradation behaviors, and the bacterial community structures were comprehensively characterized. The enriched consortia CL and CH which utilized chloramphenicol as their sole carbon and energy source could thoroughly degrade 120 mg/L chloramphenicol within 5 days, and the mineralization rate reached up to 90%. Chloramphenicol biodegradation kinetics by different enriched consortia fit the modified Gompertz model or the first-order decay model (R2≥0.97). Consortia CL could almost completely degrade 1-500 mg/L CAP with a final mineralization rate of 87.8-91.7%. Chloramphenicol 3-acetate was identified to be a major intermediate of CAP biodegradation by metabolite analysis and enzyme activity assay. 16S rRNA sequencing analysis revealed that the diversities and abundances of the main genera in the enriched consortia were distinct from each other. Forty-one core OTUs belonging to 18 genera were the core bacteria which might be related to chloramphenicol biodegradation. Among them, the genera Sphingomonas, Chryseobacterium, Cupriavidus, Bradyrhizobium, Burkholderia, and Afipia with high abundance may play potential roles for chloramphenicol biodegradation.

Enhanced dechlorination and biodegradation of 2-chloroaniline by a 2-aminoanthraquinone-graphene oxide composite under anaerobic conditions

The effect of a 2-aminoanthraquinone-graphene oxide (AQ-GO) composite on the anaerobic dechlorination and degradation of chloroanilines by an enriched bacterial consortium was investigated. The results showed that the maximal degradation efficiency of 20 mg/L 2-chloroaniline (2-CA) reached 91.4% at a dose of 20 mg/L AQ-GO in 30 d. Moreover, the pseudo-first-order rate constant of 2-CA degradation in the AQ-GO-mediated system was 2.9-fold higher than those in AQ- and GO-mediated systems alone. During this process, a synergetic effect between AQ and GO was observed, which was attributed to the increased intracellular and extracellular electron transfer pathways. GC-MS analysis showed that 2-CA could be degraded to hexanoic acid and ultimately mineralized to CO2. Illumina MiSeq sequencing revealed that additional AQ-GO significantly increased the relative abundance of Firmicutes. Further analysis showed that the populations of the genera Oscillospira, unclassified Lactobacillales, unclassified Veillonellaceae and Ruminococcus exhibited positive correlations with the rate constant of 2-CA degradation and the dehydrogenase activity of bacterial consortium. These findings indicated that AQ-GO promoted the enrichment of functional bacteria and increased the bacterial activity, resulting in the enhanced dechlorination and degradation of 2-chloroaniline.

The distinct response of phenanthrene enriched bacterial consortia to different PAHs and their degradation potential: a mangrove sediment microcosm study.

Understanding the microbial community succession to polycyclic aromatic hydrocarbons (PAHs) and identification of important degrading microbial groups are crucial for the designing of appropriate bioremediation strategies. In the present study, two distinct phenanthrene enriched bacterial consortia were treated against high molecular weight (Pyrene, Benzo (a) pyrene and Benzo (a) fluoranthene) and the response was studied in term of taxonomic variations by using High Throughput Illumina sequencing and qPCR analysis. Overall, the type of PAHs significantly affected the composition and the relative abundance of bacterial communities while no obvious difference was detected between bacterial communities of benzo (a) pyrene and benzo (a) fluoranthene treatments. Genera, Novosphingobium, Pseudomonas, Flavobacterium, Mycobacterium, Hoeflae, and Algoriphagus dominated all PAHs treatment groups indicating that they could be the key PAHs degrading phylotypes. Due to the higher abundance of gram-negative PAH-ring hydroxylating dioxygenase gene than that of gram-positive bacteria in all treated groups, we speculated that gram-negative bacteria may contribute more in the PAH degradation. The studied sediments harbored rich PAHs degrading bacterial assemblages involved in both low and high molecular weight PAHs and these findings provided new insight into the perspective of microbial PAHs bioremediation in the mangrove ecosystem.

Removal of 1,4-dioxane by titanium silicalite-1: Separation mechanisms and bioregeneration of sorption sites

Abstract 1,4-Dioxane is a probable carcinogen and trace contaminant that is difficult to remove from water because of its high solubility and low volatility. Removal of 1,4-dioxane from aqueous solutions by a set of potential adsorbents was investigated using batch experiments that revealed Titanium Silicate-1 (TS-1) as a high-capacity adsorbent (85.17 mg/g) with rapid kinetics (2 min equilibration time). The specific adsorption mechanisms at the molecular level were investigated using multiple approaches including FTIR spectra and molecular dynamics simulation of 1,4-dioxane adsorption on TS-1, which imply that the shape and size of 1,4-dioxane fits tightly into the hydrophobic straight channels of TS-1 with a diameter of 0.56 nm, and thus TS-1 provides strong van der Waals attraction within the channels. Additionally, 1,4-dioxane-water complexation was observed to connect to the frame oxygens of TS-1 via hydrogen bonds inside the channels. The calculated adsorption free energy of 1,4-dioxane was between −24.59 and −27.17 kJ/mol, which was consistent with the value of −24.89 kJ/mol derived from the adsorption isotherms at 298 K. The strong adsorption competition from nonpolar compounds 1,1,1-trichloroethane (TCA) and benzene onto TS-1 further confirmed that the adsorption was attributed to a combined mechanism of host-guest interactions including van der Waals interactions, hydrophobic interactions, and hydrogen bonding. Furthermore, 1,4-dioxane-loaded TS-1 was found to be efficiently regenerated by an enriched bacterial consortium (BD1) with recovery efficiencies for three cycles of 88.2%, 96.47% and nearly 100%, suggesting that TS-1 holds promise as a cost-effective renewable absorbent for eliminating hydrophilic organics from contaminated water supplies.

Co-metabolic degradation of the antibiotic ciprofloxacin by the enriched bacterial consortium XG and its bacterial community composition

Ciprofloxacin is a broad spectral and highly refractory antibiotic. It is an emerging pollutant. This study aimed to utilise co-metabolism as a means to degrade ciprofloxacin by a bacterial consortium. The stable bacterial consortium XG capable of efficiently degrading ciprofloxacin was successfully established through successive acclimation of indigenous microorganisms. The consortium XG was primarily consisted of Achromobacter, Bacillus, Lactococcus, Ochrobactrum, and Enterococcus as well as at least other five minor genera. A novel strain YJ17 with CIP-degrading ability was isolated from the consortium and identified as Ochrobactrum sp. The consortium XG utilised amino acids, carbohydrates, and carboxylic acids at a rate approximately 16.6-243-fold greater than the other carbon substrates, but only slow utilisation of ciprofloxacin as a sole carbon source. Ciprofloxacin can be co-metabolized along with many carbon sources, attaining degradation rates up to 63%. Glycyl-l-glutamic acid, d-cellobiose, and itaconic acid are among the substrates most favourable for co-metabolism. The metabolites of ciprofloxacin were identified by LC-QTOF-MS. Co-metabolic degradation of ciprofloxacin by consortium XG led to the removal of essential functional groups from parent compound, thus resulting in formation of metabolites with less bioactive potency. Finally, a possible biochemical pathway for the degradation of ciprofloxacin was proposed. Consortium XG possesses high potential for bioremediation of ciprofloxacin-contaminated environments in the presence of a co-substrate.

The biological treatment of synthetic fracking fluid in an extractive membrane bioreactor: Selective transport and biodegradation of hydrophobic and hydrophilic contaminants.

The biodegradation of selected organic constituents present in hydraulic fracturing wastewater were examined in an extractive membrane bioreactor (EMB) operating with Hytrel™ 3548 tubing. Synthetic hydraulic fracturing wastewater was generated via an extensive literature review and contained high concentrations (1000 mg L-1) of contaminant compounds of varied hydrophobicity, viz. methyl ethyl ketone, benzene, phenol and acetic acid, as well as 30-120 g L-1 of Cl- at low pH. This hostile wastewater was circulated through the polymeric tubing, selectively transporting the organic compounds through the membrane for biological degradation by an enriched bacterial consortium. 16S rDNA analysis revealed the presence of five dominant microbial strains within the consortium, including: Pseudomonas sp., Comamonas sp., Achromobacter sp., Lysinibacillus sp., and Oxalobacter sp. EMBs in batch operation achieved 99% removal of methyl ethyl ketone, benzene, and phenol after 72 h and effectively removed acetic acid up to its ionization point. Continuous EMB operation provided 99% removal of benzene and phenol, 96% removal of methyl ethyl ketone, and 53% of acetic acid. The treatment of synthetic hydraulic fracturing fluid demonstrated the effectiveness of carefully selected amphiphilic polymers in EMBs for treating the hydrophilic and hydrophobic organic profile found in hydraulic fracturing wastewaters.

Comparative pentachlorophenol degrading potential of two bacterial consortia isolated from tannery and pulp and paper mill effluent sludge

Pentachlorophenol (PCP) is highly toxic and recalcitrant compound which is frequently and extensively being used in a variety of industries (wood, cardboard, leather etc.) and agriculture as a preservative and biocide. The PCP degrading bacterial consortia isolated from tannery and pulp and paper mill effluents were enriched in a chemostat containing mineral salt media. The bacterial strains obtained from chemostat were characterized as two species each of Pseudomonas and Arthrobacter and one species of Sphingomonas from Tannery effluent and three species of Pseudomonas and one species of Flavobacterium from pulp and Paper mill effluent. The enriched bacterial consortia were applied for the removal of PCP in a lab-scale bioreactor and it was observed that bacterial consortium isolated from tannery effluent have more capability to degrade PCP as it removed 75% PCP within 9 days than the bacterial consortium isolated from pulp and paper mill effluent showing only 60% removal within same

Metabolism of pyrene through phthalic acid pathway by enriched bacterial consortium composed of Pseudomonas, Burkholderia, and Rhodococcus (PBR)

Polycyclic aromatic hydrocarbons (PAHs) are highly recalcitrant compounds due to their high hydrophobicity and tendency to partition in organic phase of soils. Pyrene is a high-molecular weight PAH, which has human health concerns. In the present study, a bacterial consortium, PBR, was developed from a long-term polluted site, viz., Amlakhadi, Ankleshwar, Gujarat, for effective degradation of pyrene. The consortium effectively metabolized pyrene as a sole source of carbon and energy. The consortium comprised three bacterial species, Pseudomonas sp. ASDP1, Burkholderia sp. ASDP2, and Rhodococcus sp. ASDP3. The maximum growth rate of consortium was 0.060/h and the maximum pyrene degradation rate was 16 mg/l/day. The organic and inorganic nutrients along with different surfactants did not affect pyrene degradation, but degradation rate moderately increased in the presence of sodium succinate. The significant characteristic of the consortium was that it possessed an ability to degrade six other hydrocarbons, both independently and simultaneously at 37 °C, in BHM (pH 7.0) under shaking conditions (150 rpm) and it showed resistance towards mercury at 10 mM concentration. Phthalic acid as one of the intermediates during pyrene degradation was detected through high-performance liquid chromatography (HPLC). The efficiency of consortium for pyrene degradation was validated in simulated microcosms’ study, which indicated that 99% of pyrene was metabolized by the consortium under ambient conditions.

In-Vessel Co-Composting of Food Waste Employing Enriched Bacterial Consortium.

The aim of the present study is to develop a good initial composting mix using a bacterial consortium and 2% lime for effective co-composting of food waste in a 60-litre in-vessel composter. In the experiment that lasted for 42 days, the food waste was first mixed with sawdust and 2% lime (by dry mass), then one of the reactors was inoculated with an enriched bacterial consortium, while the other served as control. The results show that inoculation of the enriched natural bacterial consortium effectively overcame the oil-laden co-composting mass in the composter and increased the rate of mineralization. In addition, CO2 evolution rate of (0.81±0.2) g/(kg·day), seed germination index of (105±3) %, extractable ammonium mass fraction of 305.78 mg/kg, C/N ratio of 16.18, pH=7.6 and electrical conductivity of 3.12 mS/cm clearly indicate that the compost was well matured and met the composting standard requirements. In contrast, control treatment exhibited a delayed thermophilic phase and did not mature after 42 days, as evidenced by the maturity parameters. Therefore, a good composting mix and potential bacterial inoculum to degrade the oil are essential for food waste co-composting systems.

Simultaneous bisphenol F degradation, heterotrophic nitrification and aerobic denitrification by a bacterial consortium

AbstractBACKGROUNDTraditional aerobic autotrophic nitrification and anoxic heterotrophic denitrification have many limitations. Recently, the simultaneous heterotrophic nitrification–aerobic denitrification (HN‐AD) process has received increasing attention. Thus, the possibility of the simultaneous removal of bisphenols and NH4+‐N via HN‐AD was investigated.RESULTSA bisphenols‐degrading bacterial consortium was enriched and capable of degrading 50 mg L−1 bisphenol A, 300 mg L−1 4,4‐dihydroxybenzophenone, 375 mg L−1 bisphenol F (BPF) and 10 mg L−1 bis(4‐hydroxyphenyl)sulfide under aerobic conditions. Further studies showed that the bacterial consortium could completely degrade 300 mg L−1 BPF and remove NH4+‐N at 35 °C with 150 rpm at the C/N ratio of over 10. Moreover, BPF mineralization and NH4+‐N reduction to N2 were observed. Clone library analysis indicated that Salmonella enterica, Enterobacter,Citrobacter and Pseudomonas could cooperate to degrade BPF and reduce NH4+‐N to N2. Among these species, the isolated Pseudomonas sp. HS‐2 was capable of simultaneous BPF degradation and NH4+‐N removal via HN‐AD.CONCLUSIONThe experimental results demonstrated that the enriched bacterial consortium and the isolated strain HS‐2 could simultaneously remove BPF and NH4+‐N via HN‐AD, indicating that this is a potential way for the treatment of wastewaters containing these compounds. © 2016 Society of Chemical Industry

Reuse of polycyclic aromatic hydrocarbons (PAHs) contaminated soil washing effluent by bioaugmentation/biostimulation process

Abstract The reuse feasibility of the bioremediated effluent of the combination of sequential soil washing followed by biological treatment for removal of phenanthrene (PHE) from contaminated soils was investigated for several soil washing. In the first stage a removal efficiency of 74.4% ± 3.5% was obtained under the optimum conditions of: surfactant (Tween 80) concentration of 5000 mg/L, liquid/soil ratio of 30 v/w, humic acid concentration of 2.31 mg/L (6.93%), and washing time of 2 h. In the second stage complete biodegradation of PHE from soil washing effluent was achieved by inoculating enriched bacterial consortium (OD600nm = 1) within 7 days. Reuse possibility of biologically treated solution for the next cycles of soil washing process was conducted by adjusting the surfactant concentration. The findings displayed that reusability of the biologically recycled solution was maintained up to 7th cycle, reaching a removal efficiency of >99% and >97% in artificial and real contaminated soils respectively, indicating the effectiveness of reused surfactant solution.

Biotransformation of mixture of dyes by enriched bacterial consortium ASD

AbstractDye effluents released from textile industries has gradually entrenched the roots of peril to majority of the water bodies. Considering the alarming need of innovative bioremediation technologies, the present study aims to evaluate the biodegradation potential of a bacterial consortium ASD for mineralization of a mixture of structurally different dyes. Consortium ASD, developed from dye contaminated soil from Vatva industrial estate, constitutes of four bacterial strains viz. Pseudomonas sp., Brevibacillus sp. and two strains of Stenotrophomonas sp. The intense metabolic activity of these strains together, led to 94% ADMI removal (American dye Manufacturers Institute) of 100 mg l−1 of a mixture of dyes in the presence of starch (0.1%, w/v) and proteose peptone (0.4%, w/v) within 24 h at 37°C under static (microaerophilic) condition and could tolerate up to 400 mg l−1 of dye mixture. Consortium was also able to reduce total organic carbon and chemical oxygen demand by 85 and 78% within 24 h. Signif...