Biodegradation Of Nonylphenol Research Articles

Exploring the potential of microbial fuel cell-assisted biodegradation of nonylphenol

Exploring the potential of microbial fuel cell-assisted biodegradation of nonylphenol

Pseudomonas aeruginosa improved the phytoremediation efficiency of ryegrass on nonylphenol-cadmium co-contaminated soil.

The effect of Pseudomonas aeruginosa (P. aeruginosa) on the phytoremediation efficiency of ryegrass on soil contaminated with nonylphenol (NP) and cadmium (Cd) was investigated by pot experiments. Pseudomonas aeruginosa application stimulated the adsorption of Cd by ryegrass and facilitated the biodegradation of NP in the soil. Exogenous P. aeruginosa inoculation increased the activities of urease, dehydrogenase, and polyphenol oxidase in the soil of the T4 treatment by 38.5%, 50.0%, and 56.5% compared to that of the T2 treatment, respectively. There was a significant positive correlation between the activities of dehydrogenase and polyphenol oxidase and the NP removal rate (P < 0.001). The relative abundances of beneficial microorganisms (such as Sphingomonas, Lysobacter, Streptomyces, Chloroflexia, Deltaproteobacteria, and Alphaproteobacteria) were increased as a result of P. aeruginosa inoculation. These microorganisms play important roles in nutrient cycling, Cd adsorption, and NP degradation. Additionally, P. aeruginosa was not the dominate bacterial species at the end of the experiment. According to this study, P. aeruginosa application improved the phytoremediation efficiency of ryegrass on soil contaminated with NP and Cd, with a minimal risk of alien microbial invasion.

Toxicity alleviation and metabolism enhancement of nonylphenol in green algae Dictyosphaerium sp. by NaHCO3

Nonylphenol (NP) toxicity limits the improvements in its algal remediation efficiency. This study comprehensively investigated the performance and mechanism of NaHCO3-driving effects on NP-exposed algae. The results showed that NaHCO3 enhanced algal resistance to NP and the corresponding EC50 values increased 1.31–4.25 times. Further, the toxicological effects of NP reduced with increasing pyrenoid volume and chlorophyll and carotenoids production, and decreasing cellular damage degree. Moreover, the concentration of extracellular polymeric substances was enhanced and more NP adsorption sites were formed. Consistently, RNA-seq demonstrated significant expression alterations in genes related to energy metabolism, cellular synthesis, photosynthesis, and carbon fixation. Besides, NP biodegradation rate was increased by 15.2 % and 11.1 % in the 1, and 4 mg/L NP treatments, respectively. Identification of degradation intermediates and their toxicity via Ecological Structure Activity Relationship program showed that NaHCO3 accelerated sequential α-C removal from NP in algae with faster generation of less toxic metabolites, namely, 4-ethylphenol, 4-cresol and 4-hydroxybenzoic acid. This study provides new insights into the role of NaHCO3 in toxicity alleviation and metabolism enhancement of NP in algae and can assist NP bioremediation efforts in aquatic environment.

A microcosm approach for evaluating the microbial nonylphenol and butyltin biodegradation and bacterial community shifts in co-contaminated bottom sediments from the Gulf of Finland, the Baltic Sea.

Pollution of aquatic ecosystems with nonylphenol (NP) and butyltins (BuTs) is of great concern due to their effects on endocrine activity, toxicity to aquatic organisms, and extended persistence in sediments. The impact of contamination with NP and/or BuTs on the microbial community structure in marine sediments was investigated using microcosms and high-throughput sequencing. Sediment microcosms with NP (300 mg/kg) and/or BuTs (95 mg/kg) were constructed. Complete removal of monobutyltin (MBT) occurred in the microcosms after 240 days of incubation, while a residual NP rate was 40%. The content of toxic tributyltin (TBT) and dibutyltin (DBT) in the sediments did not change notably. Co-contamination of the sediments with NP and BuTs did not affect the processes of their degradation. The pollutants in the microcosms could have been biodegraded by autochthonous microorganisms. Significantly different and less diverse bacterial communities were observed in the contaminated sediments compared to non-contaminated control. Firmicutes and Gammaproteobacteria dominated in the NP treatment, Actinobacteria and Alphaproteobacteria in the BuT treatment, and Gammaproteobacteria, Alphaproteobacteria, Firmicutes, and Acidobacteria in the NP-BuT mixture treatment. The prevalence of microorganisms from the bacterial genera Halothiobacillus, Geothrix, Methanosarcina, Dyella, Parvibaculum, Pseudomonas, Proteiniclasticum, and bacteria affiliated with the order Rhizobiales may indicate their role in biodegradation of NP and BuTs in the co-contaminated sediments. This study can provide some new insights towards NP and BuT biodegradation and microbial ecology in NP-BuT co-contaminated environment.

Growth performance, antioxidant response, biodegradation and transcriptome analysis of Chlorella pyrenoidosa after nonylphenol exposure

Chlorella pyrenoidosa was exposed to nonylphenol (NP) to investigate the tolerance, antioxidant response, removal efficiency, and biodegradation mechanism. We conducted studies on algal biomass, chlorophyll a content, and photosynthetic activity, and found that C. pyrenoidosa exhibited a high tolerance even at 8 mg L−1 of NP. Changes in peroxidase (POD) and superoxide dismutase (SOD) activities indicated that the NP-induced oxidative stress caused oxidant damage, which increased the malondialdehyde (MDA) content. After culturing for 120 h, the NP removal efficiency of C. pyrenoidosa was 89%, 59%, 49%, and 48% in the 2, 4, 6, and 8 mg L−1 treatment groups, respectively. Degradation intermediates determined by GC–MS suggested that the biodegradation of NP in C. pyrenoidosa originated from the long alkyl chain. In addition, transcriptome analysis indicated that NP affected photosynthesis, antioxidase, and oxidoreductase activity-related genes. In summary, our results indicated that C. pyrenoidosa is a species that exhibits high tolerance and biodegradation capacity toward NP.

Phytotoxicity, Bioaccumulation, and Degradation of Nonylphenol in Different Microalgal Species without Bacterial Influences.

Nonylphenol (NP) is a contaminant that has negative impacts on aquatic organisms. To investigate its phytotoxicity, bioaccumulation, and degradation in algae without associated bacteria, six freshwater microalgae—Ankistrodesmus acicularis, Chlorella vulgaris, Chroococcus minutus, Scenedesmus obliquus, Scenedesmus quadricauda, and Selenastrum bibraianum—in bacteria-free cultures were studied. When exposed to 0.5–3.0 mg L−1 NP for 4 days, cell growth and photosynthesis, including maximal photochemistry (Fv/Fm), were suppressed progressively. The antioxidant responses of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) showed species differences. While the antioxidant enzymes in C. vulgaris and S. obliquus were more active with the increase of NP (0–3 mg L−1), they dropped in the other four algae at concentrations of 1 and 1.5 mg L−1. Therefore, C. vulgaris and S. obliquus were designated as NP-tolerant species and showed more conspicuous and faster changes of antioxidant reactions compared with the four NP-sensitive species. All six species degraded NP, but A. acicularis was more reactive at low NP concentrations (<1 mg L−1), suggesting its possible application in sewage treatment for its potential for effective NP removal from water bodies in a suitable scope. Therefore, the conclusion is that biodegradation of NP by algae is species specific.

Changes in microbiota of Baltic Sea coastal sediments caused by nonylphenol contamination

AbstractThe effect of nonylphenols (NPs) on the sediment microbial population was investigated in laboratory experiments. Adaptation of sediment microorganisms to NP contamination proceeds through the evolution of NP‐tolerant populations and the reduction of stress by biodegradation of NPs. The amount of bacteria that is able to degrade NPs in contaminated sediments was positively correlated with the total heterotrophic bacteria counts, indicating that the pattern of change was associated with NPs. The disappearance of NPs from the sediments by microbial degradation demonstrated a half‐life of 43–71 days. NP contamination resulted in decreased sediment microbial diversity. A decrease in both the Shannon diversity index and Pielou evenness index together with an increase in Simpson's dominance index were common change patterns observed across NP‐contaminated sediment samples. The observed changes in microbial diversity were sustainable. There was a very slow re‐establishment of the original diversity, particularly in the fungal community of NP‐contaminated sediments.

Biosorption and Biodegradation of the Environmental Hormone Nonylphenol By Four Marine Microalgae

Microalgae are the most abundant microorganisms in aquatic environments, and many possess the ability to remove organic contaminants. The presence of endocrine disruption compounds (EDCs) in many coastal marine systems and their associated risks have elicited great concern, especially in the case of nonylphenol (NP), which is classified as a priority contaminate by the U.S. EPA. In this context, batch experiments were conducted to investigate the intracellular absorption, extracellular adsorption and biodegradation of NP by four species of marine microalgae: Phaeocystis globosa, Nannochloropsis oculata, Dunaliella salina and Platymonas subcordiformis. The results showed a sharp reduction of NP in medium containing the four microalgal species during the first 24 h of incubation, and the four species exhibited the greatest capacity for NP adsorption and absorption within 24 h of culture. However, the amount of NP absorbed and adsorbed by all four microalgae decreased with increasing time in culture, and intracellular absorption was greater than extracellular adsorption. After 120 h of exposure to NP, the four species could biodegrade most of the NP in the medium, with efficiencies ranging from 43.43 to 90.94%. In sum, we found that the four microalgae have high biodegradation percentages and can thus improve the bioremediation of NP-contaminated water.

Simultaneous enhancement of nonylphenol biodegradation and short-chain fatty acids production in waste activated sludge under acidogenic conditions

Nonylphenol (NP) biodegradation in waste activated sludge (WAS) under anaerobic conditions is usually slow, and no information on NP biodegradation under acidogenic conditions is currently available. In this study, the simultaneous enhancement of NP biodegradation and short-chain fatty acids (SCFAs) accumulation in a WAS fermentation system under acidogenic conditions was accomplished by controlling pH 10 and adding sodium lauryl sulfate (SLS). The biodegradation efficiency of NP was found to be 55.5% within 8 d under acidogenic conditions, much higher than that in the control (24.6%). Meanwhile, the concentration of SCFAs under the same conditions for NP biodegradation was increased from 2234 mg COD/L (control) to 4691 mg COD/L (at pH 10 with SLS). Mechanism study revealed that the abundances of both NP-degrading microorganisms and acidogenic bacteria increased under acidogenic conditions. Altering the enzymatic activity and the quantity of functional genes in the acidogenic fermentation system were beneficial to NP biodegradation and SCFAs accumulation. Furthermore, organic substrates available for uptake by NP-degrading and acidogenic bacteria, i.e. NP, protein and carbohydrate, were released from WAS under acidogenic conditions. More importantly, intermediate substrates involved in acidogenic fermentation were advantageous to the cometabolic biodegradation of NP.

Acidogenic bacteria assisted biodegradation of nonylphenol in waste activated sludge during anaerobic fermentation for short-chain fatty acids production

Nonylphenol (NP) biodegradation under anaerobic conditions is difficult. Here, enhancement of anaerobic NP biodegradation mainly by regulating the role of acidogenic bacteria during anaerobic fermentation of waste activated sludge (WAS) for short-chain fatty acids production is reported. The maximum degradation efficiency of NP (69.4%) was achieved under conditions of pH 10.0 and 10 mg/L Brij 35 within 8 d, which was nearly 3-fold of that in the control (24.6%). Mechanism exploration revealed that the bioavailability of NP and specific NP-degrading bacteria and their functional genes were advantageous to NP biodegradation with alkaline pH and surfactant. More importantly, acidogenic bacteria, the dominant functional bacteria in WAS fermentation systems, were demonstrated to be involved in NP anaerobic biodegradation by providing intermediate organic substrates, as well as through their intrinsic NP-degrading abilities. Possible pathways of NP biodegradation assisted by acidogenic bacteria during anaerobic fermentation were also proposed based on the detected metabolites.

The Relationship Study of Biomass, Situation, and Artificial Control: the Degradation of NP Using Estuary-Derived Fungi

Cultural situation generally played a crucial role on biodegradation mechanism establishment of pollutant. Extensive studies had focused on the optimization of cultivation environment based on in situ conditions. However, there were still few reports on the effects of artificial control on microbial growth and degradation. In this work, the relationship of biomass, situation, and artificial control was explored through the biodegradation of nonylphenols as standard containments by four trains named A. niger, A. terreus SHPP01, A. terreus NIH2624, and T. aff. harzianum from the estuary sediment of Jiaozhou Bay. Various culture conditions covering mineral salt medium, glucose synergistic medium, and carbon rich complex medium had been used to quest the relationship. As a conclusion, different strains usually showed different mechanisms within the same media. The correlation ship between biomass and degradation and removal rate was positive, and the natural medium was usually the best choice for microbial study in situ simulation. Hence, our study provided a valuable reference for the realization of more efficient and rapid biodegradation of pollutants.

Biodegradation of nonylphenol during aerobic composting of sewage sludge under two intermittent aeration treatments in a full-scale plant

The urbanization and industrialization of cities around the coastal region of the Bohai Sea have produced large amounts of sewage sludge from sewage treatment plants. Research on the biodegradation of nonylphenol (NP) and the influencing factors of such biodegradation during sewage sludge composting is important to control pollution caused by land application of sewage sludge. The present study investigated the effect of aeration on NP biodegradation and the microbe community during aerobic composting under two intermittent aeration treatments in a full-scale plant of sewage sludge, sawdust, and returned compost at a ratio of 6:3:1. The results showed that 65% of NP was biodegraded and that Bacillus was the dominant bacterial species in the mesophilic phase. The amount of NP biodegraded in the mesophilic phase was 68.3%, which accounted for 64.6% of the total amount of biodegraded NP. The amount of NP biodegraded under high-volume aeration was 19.6% higher than that under low-volume aeration. Bacillus was dominant for 60.9% of the composting period under high-volume aeration, compared to 22.7% dominance under low-volume aeration. In the thermophilic phase, high-volume aeration promoted the biodegradation of NP and Bacillus remained the dominant bacterial species. In the cooling and stable phases, the contents of NP underwent insignificant change while different dominant bacteria were observed in the two treatments. NP was mostly biodegraded by Bacillus, and the rate of biodegradation was significantly correlated with the abundance of Bacillus (r = 0.63, p < 0.05). Under aeration, Bacillus remained the dominant bacteria, especially in the thermal phase; this phenomenon possibly increased the biodegradation efficiency of NP. High-volume aeration accelerated the activity and prolonged the survival of Bacillus. The risk of organic pollution could be decreased prior to sewage sludge reuse in soil by adjusting the ventilation strategies of aerobic compost measurements.

Molecular docking simulation on the interactions of laccase from Trametes versicolor with nonylphenol and octylphenol isomers.

The biodegradation of nonylphenol (NP) and octylphenol (OP) isomers by laccase has attracted increasing concerns. However, the interaction mechanism between these isomers and laccase remains unclear, especially for fungal laccase. In this work, molecular docking was employed to study this issue. The results indicated that the structural characteristic of alkyl chain (position and branching degree) affected the interactions between Trametes versicolor (T. versicolor) laccase and isomers. The binding affinity between them was closely related to the position and branching degree of alkyl chain in isomers. The binding affinities between linear isomers and T. versicolor laccase were para-position < meta-position < ortho-position. For selected branched 4-NP, the isomers with bulky α-substituent in alkyl chain had higher binding affinities. In addition, hydrophobic contacts between T. versicolor laccase and NP or OP isomers were necessary, while H-bonds were optional. The isomers with similar structure may have more common residues involved in hydrophobic contacts. The H-bonds of selected NPs and OPs were all connected with phenolic hydroxyl. These findings provide an insight into detailed interaction mechanism between T. versicolor laccase and isomers of NP and OP. It is helpful to broaden the knowledge of degradation technology of NPs and OPs and provide theoretical basis on biological remediation of these contaminants.

Exploration of biodegradation mechanisms of black carbon-bound nonylphenol in black carbon-amended sediment

The present study aimed to investigate biodegradation mechanisms of black carbon (BC)-bound contaminants in BC-amended sediment when BC was applied to control organic pollution. The single-point Tenax desorption technique was applied to track the species changes of nonylphenol (NP) during biodegradation process in the rice straw carbon (RC)-amended sediment. And the correlation between the biodegradation and desorption of NP was analyzed. Results showed that microorganisms firstly degraded the rapid-desorbing NP (6 h Tenax desorption) in RC-amended sediment. The biodegradation facilitated the desorption of slow-desorbing NP, which was subsequently degraded as well (192 h Tenax desorption). Notably, the final amount of NP degradation was greater than that of NP desorption, indicating that absorbed NP by RC amendment can be degraded by microorganisms. Finally, the residual NP amount in RC-amended sediment was decided by RC content and its physicochemical property. Moreover, the presence of the biofilm was observed by the confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) so that microorganisms were able to overcome the mass transfer resistance and directly utilized the absorbed NP. Therefore, single-point Tenax desorption alone may not be an adequate basis for the prediction of the bioaccessibility of contaminants to microorganisms or bioremediation potential in BC-amended sediment.

Effect of rice-straw biochar on selective biodegradation of nonylphenols in isomer specificity.

In a previous study, we found that rice-straw biochar degraded and removed hydrophobic organic contaminants (HOCs) through coupled adsorption-biodegradation. However, few studies have determined whether biochar affects HOC isomer degradation and isomer-selective biodegradation or whether biochar can alter HOC isomer features, resulting in changes to HOC isomer residues in water environments. In this study, the effects of biochar at two dosages (0.001 and 0.01g) on the biodegradation of ten isomers of a typical xenoestrogen of nonylphenol (NP) were evaluated. The results revealed that there were no effects of biochar on the adsorption of NP isomers. However, biochar addition affected the biodegradation of a specific isomer without altering the features of the NP isomers. The treatment of NP isomers with Pseudoxanthomonas sp. yielded degradation ratios ranging from 60.7 to 100%. At 0.001 g biochar treatment, the degradation of eight NP isomers was enhanced (except for NP194 and NP193a+b) due to their bulky structures. The degradation of the ten NP isomers was inhibited when 0.01 g biochar was added. These findings characterized the effects of biochar on NP isomer contaminants and provided basic information for the application of biochar for the remediation of NP isomer contaminants.

Role of biochar in biodegradation of nonylphenol in sediment: Increasing microbial activity versus decreasing bioavailability

The observed strong sorption of hydrophobic organic contaminants (HOCs) to biochar presents potential implications for HOCs bioavailability and bioaccessibility in sediments, while biochar could impact sediment microbial ecology. However, the comprehensive study on the effects of biochar on HOC biodegradation coupled with bioavailability and microbial ecology are rarely documented. In this paper, the effects of biochar on the biodegradation of nonylphenol (NP) were investigated using 3 different NP concentrations (20, 50 and 500 mg/Kg) in sediments amended with different percentage of rice straw biochar (RC). Results showed that the influence of RC on NP biodegradation varied with different NP concentrations. At low NP concentrations, RC suppressed NP biodegradation by reducing NP bioavailability, while at high NP concentrations, moderate RC addition promoted biodegradation by reducing toxicity of NP to microbes. The effects of NP on microbial community structures were significant (P < 0.01), but those of RC were not significant (P > 0.05). The RC affected microorganisms through altering NP toxicity, microbial quantity and activity, but not microbial community structures. This study indicated that there could be an optimal biochar percentage in biochar-sediment systems at different HOC concentrations, which strengthened HOC biodegradation process and accelerated biodegradation rate, forming adsorption-biodegradation coupled bioremediation.

Effect of Cadmium on Biodegradation of Nonylphenol by Pseudomonas aeruginosa

The influence of Cd on the degradation of nonylphenol (NP) by P.aeruginosa SH1 was investigated in this study.The investigation revealed that biomass of the strain was significantly declined with the increase of Cd2+ concentration.The biomass was declined by 27.1% in the presence of 10 mg·L-1Cd2+ after 24 h.The addition of Cd2+ had a great influence on adsorption of NP by the strain.As for the effect of living stain,adsorption by P.aeruginosa SH1 cells was stimulated at low concentrations of Cd2+(0.5 mg·L-1),while inhibited at higher levels (≥5 mg·L-1).As for inactivation of microbes,adsorption by cells was stimulated at higher concentrations,but was only slightly influenced at low levels.The results showed that the intracellular enzymes had much greater degradation rate than the living cells.Different concentrations of Cd2+ had different effects on bacteria and intracellular enzyme degradation of NP separately.The degradation efficiency when using intracellular enzymes and bacteria was inhibited at higher levels of Cd2+ and the intracellular enzyme inhibition was more significant.Degradation by cells was stimulated at low concentrations of Cd2+,but no significant impact was found on that by intracellular enzymes.The degradation process of NP by intracellular enzymes of the strain conformed to the first-order kinetic model.The highest reaction rate was achieved when the concentrations of Cd2+ was 0.5 mg·L-1 and the half-life of this substrate was 5.5 h.However,the degradation process of NP by the strain did not conform to the first-order kinetic model.

Removal and Biodegradation of Nonylphenol by Four Freshwater Microalgae.

The removal and biodegradation of nonylphenol (NP) by four freshwater microalgae, including three green algae (Scendesmus quadriauda, Chlorella vulgaris, and Ankistrodesmus acicularis) and one cyanobacterium (Chroococcus minutus) were studied in bacteria-free cultures exposed to different concentrations of NP for 5 days. All four algal species showed a rapid and high ability to remove NP (including bioaccumulation and biodegradation). Among these species, A. acicularis (Ankistrodesmus acicularis) had the highest NP removal rate (83.77%) at 120 h when exposed to different NP treatments (0.5–2.5 mg·L−1), followed by C. vulgaris (Chlorella vulgaris) (80.80%), S. quadriauda (Scendesmus quadriauda) (70.96%) and C. minutus (Chroococcus minutus) (64.26%). C. vulgaris had the highest NP biodegradation percentage (68.80%) at 120 h, followed by A. acicularis (65.63%), S. quadriauda (63.10%); and C. minutus (34.91%). The extracellular NP contents were lower than the intracellular NP contents in all tested algae. The ratio of the extracellular NP content and the intracellular NP content ranged from 0.04 to 0.85. Therefore, the removal of NP from the medium was mainly due to the algal degradation. These results indicate that A. acicularis and C. vulgaris are more tolerant to NP and could be used for treatment of NP contaminated aqueous systems effectively by bioremoval and biodegradation.

Nonylphenol biodegradation characterizations and bacterial composition analysis of an effective consortium NP-M2

Nonylphenol (NP), ubiquitously detected as the degradation product of nonionic surfactants nonylphenol polyethoxylates, has been reported as an endocrine disrupter. However, most pure microorganisms can degrade only limited species of NP with low degradation efficiencies. To establish a microbial consortium that can effectively degrade different forms of NP, in this study, we isolated a facultative microbial consortium NP-M2 and characterized the biodegradation of NP by it. NP-M2 could degrade 75.61% and 89.75% of 1000 mg/L NP within 48 h and 8 days, respectively; an efficiency higher than that of any other consortium or pure microorganism reported so far. The addition of yeast extract promoted the biodegradation more significantly than that of glucose. Moreover, surface-active compounds secreted into the extracellular environment were hypothesized to promote high-efficiency metabolism of NP. The detoxification of NP by this consortium was determined. The degradation pathway was hypothesized to be initiated by oxidization of the benzene ring, followed by step-wise side-chain biodegradation. The bacterial composition of NP-M2 was determined using 16S rDNA library, and the consortium was found to mainly comprise members of the Sphingomonas, Pseudomonas, Alicycliphilus, and Acidovorax genera, with the former two accounting for 86.86% of the consortium. The high degradation efficiency of NP-M2 indicated that it could be a promising candidate for NP bioremediation in situ.

The nonylphenol biodegradation study by estuary sediment-derived fungus Penicillium simplicissimum.

Nonylphenols (NPs) are persistent organic pollutants (POPs) with estrogenic properties that can perform endocrine-disrupting activities. By using high-concentration NP as environmental selection pressure, one NP biodegradation strain named NPF-4 was isolated and purified from estuary sediment of the Moshui River. It was identified as Penicillium simplicissimum (PS1) by appearance and 18S rDNA analysis. In different culture situations, the strain mass growth and biodegradation ability were evaluated. Within 4-n-nonylphenol (4-n-NP) initial concentration of 20mgL(-1), it could be degraded 53.76, 90.08, and 100.00% at 3, 7, and 14days, respectively. In feeding experiments, it showed that NPF-4 could use 4-n-NP as a sole carbon source. Based on seven products/intermediates detected with GC and LC-MS, a novel biopathway for 4-n-NP biodegradation was proposed, in which sequential hydroxylation, oxidation, and decarboxylation at terminal β-C atom may occur for 4-n-NP detoxification, even complete mineralization in the end.