Biodegradation Of Phthalate Esters Research Articles

The occurrence, fate, toxicity, and biodegradation of phthalate esters: An overview.

Phthalate esters (PAEs) are a class of emerging xenobiotic compounds that are extensively used as plasticizers. In recent times, there has been an increasing concern over the risk of this pervasive pollution exposure causing endocrine disruption and carcinogenicity in humans and animals. The widespread use of PAEs in home and industrial applications has resulted in their discharge in aquatic bodies via leaching, volatilization, and precipitation. In this overview, the current state of PAE pollution, its potential origins, its fate, as well as its effects on the aquatic environment are discussed. A state-of-the-art review of several studies in the literature that focus on the biological degradation of PAEs is included in this study. The paper aims to provide a comprehensive view of current research on PAEs in the environment, highlighting its fate and alleviated risks on the aquatic biotas, their challenges, future prospects, and the need for good management and policies for its remediation. PRACTITIONER POINTS: Occurrence of phthalate esters was summarized in various environmental matrices along with its serious ecotoxicological implications on biota. Wastewater is the prime source of PAEs contamination. Lack of species-specific effects on biota due to dose, exposure route, and susceptibility. The predominant route to mineralization in PAEs is biodegradation. A critical analysis of worldwide PAE production and consumption identifies the necessity for global PAE production, consumption, and release policies.

Global industrial enzymes market projected to reach worth $9.2 bn by 2027

A novel lipase gene (McLipB) was cloned from a thermophilic fungus Malbranchea cinnamomea and expressed in Pichia pastoris. The deduced amino acid sequence of the lipase (McLipB) shared the highest identity of 46% with the Candida rugosa lipase LIP4. The extracellular lipase activity of 4304 U/mL with protein concentration of 7.7 mg/mL was achieved in a 5-L fermentor. The optimal pH and temperature of McLipB were 7.5 and 40 °C, respectively. The lipase showed high specificity towards triglycerides with short and medium chain fatty acids, and had non-position specificity. McLipB hydrolyzed butter to produce mainly butyric acid, hexanoic acid and a small amount of octanoic acid and decanoic acid. Furthermore, it degraded more than 90% dipropyl phthalate, dibutyl phthalate and dihexyl phthalate to their corresponding monoalkyl phthalates. The properties of McLipB indicate that it has great application potential for production of lipolyzed milkfat flavor and biodegradation of phthalate esters.

Biodegradation of phthalate esters by Pantoea dispersa BJQ0007 isolated from Baijiu

Baijiu is a famous Chinese alcoholic beverage and is produced by the co-fermentation of microorganisms with grains as the raw materials. Phthalate esters (PAEs) are toxic chemicals and frequently detected in Baijiu. Identification of microorganisms that could degrade PAEs was recognized as a possible way to solve the contamination. Pantoea spp. are one kind of dominant microorganisms for manufacturing Baijiu. Here, Pantoea dispersa BJQ0007 was isolated from Baijiu fermentation starter and showed the ability in degrading dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, and di-(2-ethylhexyl) phthalate, with di-(2-ethylhexyl) phthalate as the preferred substrate. The whole genome was sequenced with a chromosome of 4,325,134 bp and three plasmids. The metabolic pathway of PAE degradation is proposed with an uncommon metabolic step by converting phthalate monoester to benzoate ester based on metabolic intermediate analysis and genome annotation. Two enzymes responsible for ester bond hydrolysis of PAEs were identified and belonged to enzyme families IV and not defined, respectively. The results revealed PAE degradation of Pantoea species and would promote the safety control of Baijiu products by offering bacterial and enzymatic resources.

Biodegradation of phthalate esters by Paracoccus kondratievae BJQ0001 isolated from Jiuqu (Baijiu fermentation starter) and identification of the ester bond hydrolysis enzyme

Phthalate ester (PAE) pollution is an increasing problem globally. Paracoccus kondratievae BJQ0001 was isolated from the fermentation starter of Baijiu and showed an efficient degradation capability toward PAEs. To our poor knowledge, this is the first report of a P. kondratievae strain capable of degrading PAEs. The first complete genome sequence of P. kondratievae was presented without gaps, and composed of two circular chromosomes and one plasmid. The species simultaneously degraded di-methyl phthalate (DMP), di-ethyl phthalate (DEP), di-butyl phthalate (DBP), di-isobutyl phthalate (DIBP) and di-(2-ethylhexyl) phthalate (DEHP), with DMP and DEP as the preferred substrates. The half-life (t1/2) of DMP was only 6.34 h with an initial concentration of 200 mg/L. Combined with gene annotation and metabolic intermediate analysis, a metabolic pathway was proposed for the species. Benzoic acid, the intermediate of anaerobic PAE metabolism, was identified in the aerobic degradation process. Two key enzymes for alkyl ester bond hydrolysis were obtained, and belonged to families IV and VI of hydrolases, respectively. These results will promote the investigation of PAE degradation by P. kondratievae, and provide useful information for improving the quality control of food and environmental PAE treatment.

Biodegradation of phthalate esters in four agricultural soils: Main influencing factors and mechanisms

Phthalate esters (PAEs) are among the frequently detected organic pollutants in agricultural soils. Here, we investigated adsorption and biodegradation behaviors of di-ethyl phthalate (DEP) and dibutyl phthalate (DBP) in the soils collected from four regions in China: Changchun (CC), Changsha (CS), Cangzhou (CZ), and Yinchuan (YC). The results demonstrated that soil organic matter content crucially influenced the adsorption progress. However, the calculated degradation rates of PAEs in the four soils had no significant correlation with their adsorption capacity, suggesting that PAEs' bioavailability might be not the limiting factor governing their degradation. Furthermore, homogeneous biodegradation experiments were performed in the soil solutions extracted from different regional soils. Results showed that biodegradation of PAEs was influenced by the soil solution's pH and its concentration of dissolved organic matter (DOM). To better understand the accelerating mechanism of DOM, bacterial growth and enzyme activity in the presence of Humic acid (HA) and Fulvic acid (FA) were determined, and the degradation of PAEs by intracellular enzymes were also investigated. These results suggested that HA, FA, and other forms of DOM were actively involved in this biodegradation process in two ways: namely, via nutritional support and sequestration of PAEs. We conclude that the actual impact of soil organic matter (SOM) upon PAEs' biodegradation in soils arose from the net outcome of these two opposing effects.

Biochemical characterization of a novel lipase from Malbranchea cinnamomea suitable for production of lipolyzed milkfat flavor and biodegradation of phthalate esters

A novel lipase gene (McLipB) was cloned from a thermophilic fungus Malbranchea cinnamomea and expressed in Pichia pastoris. The deduced amino acid sequence of the lipase (McLipB) shared the highest identity of 46% with the Candida rugosa lipase LIP4. The extracellular lipase activity of 4304 U/mL with protein concentration of 7.7 mg/mL was achieved in a 5-L fermentor. The optimal pH and temperature of McLipB were 7.5 and 40 °C, respectively. The lipase showed high specificity towards triglycerides with short and medium chain fatty acids, and had non-position specificity. McLipB hydrolyzed butter to produce mainly butyric acid, hexanoic acid and a small amount of octanoic acid and decanoic acid. Furthermore, it degraded more than 90% dipropyl phthalate, dibutyl phthalate and dihexyl phthalate to their corresponding monoalkyl phthalates. The properties of McLipB indicate that it has great application potential for production of lipolyzed milkfat flavor and biodegradation of phthalate esters.

WITHDRAWN: Biochemical characterization of a novel lipase from Malbranchea cinnamomea suitable for production of lipolyzed milkfat flavor and biodegradation of phthalate esters

WITHDRAWN: Biochemical characterization of a novel lipase from Malbranchea cinnamomea suitable for production of lipolyzed milkfat flavor and biodegradation of phthalate esters

Biodegradation of Phthalate Esters by a Newly Isolated Acinetobacter sp. Strain LMB-5 and Characteristics of Its Esterase

Phthalate esters (PAEs) are extensively applied in industry, and they migrate to environment during the process of production, employ, and treatment and are difficult to be degraded in nature. However, some microorganisms could use them as the carbon source to growth. In this study, an Acinetobacter sp. strain LMB-5, capable of utilizing PAEs, was isolated from a vegetable greenhouse soil. The degradation capability of strain LMB-5 was also investigated by incubation in mineral salt medium containing different PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), and di-(2-ethylhexyl) phthalate (DEHP). The strain could grow well with DMP, DEP, DBP, and DEHP. When the concentration of DBP increased from 100 to 400 mg L−1, the half-life extended from 9.5 to 15.5 h. In the concentration range of DBP, the degradation ability of strain LMB-5 could be described by first-order kinetics. During the biodegradation of DBP, three intermediates, 1,2-benzenedicarboxylic acid, butyl methyl ester, DMP, and phthalic acid (PA) were detected, and the proposed pathway of DBP was identified. By analysis of bioinformatics, one esterase was cloned from the genome of LMB-5 and expressed in Escherichia coli. It displayed an ability to break the ester bonds of DBP. The enzyme exhibited maximal activity at pH 7.0 and 40 °C with DBP as the substrate. It was activated by Cu2+ and Fe3+ and had a high activity in the presence of low concentrations of methanol or dimethylsulfoxide (each 10%, volume:volume). The Acinetobacter sp. strain LMB-5 may make a contribution to the remediation of soils polluted by PAEs in the future.

Biodegradation of phthalate esters by newly isolated Rhizobium sp. LMB-1 and its biochemical pathway of di-n -butyl phthalate

To isolate a novel strain that could degrade many kinds PAEs efficiently and investigate the DBP-degrading pathway in this strain. Based on its 16S rRNA gene sequence, the strain was identified as Rhizobium sp. This strain, named LMB-1, can also utilize phthalates, such as DEHP, DMP, DBP and DEP. During the degradation of DBP, six possible metabolites, diethyl phthalate, mono-ethyl phthalate, di-methyl phthalate, mono-methyl phthalate, phthalic acid and tartaric acid, were identified by gas chromatography-mass spectrometry (GC-MS) analysis, and the degradation pathway of DBP was also identified in this study. In summary, strain LMB-1, identified as Rhizobium sp., was found to be capable of efficiently degrading PAEs, and it was determined that the strain degraded DMP completely within 45h. DEP, DMP, MEP, MMP, PA and tartaric acid were detected during the course of DBP degradation by LMB-1. We propose that this strain could completely degrade DBP or other PAEs. Our results offer a novel and potential candidate, Rhizobium sp. LMB-1, for use in the bioremediation of cultivated soil contaminated by PAEs. This is the first report concerning the complete degradation of phthalate esters by Rhizobium sp.

Biodegradation of Phthalate Esters by Variovorax sp

Biodegradation of dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) and their mixture by a bacterial strain that was isolated from garbage dumped soil nearby Indian Institute of Technology Bombay is reported. The strain was isolated by enrichment technique using a mixture of DMP, DEP and DBP in the growth medium and had the ability to utilize the above phthalate esters as the sole source of carbon and energy under aerobic conditions. The bacterial isolate was identified as Variovorax sp. based on 16S r-DNA sequence analysis. Variovorax sp. degraded >99% of 300mg L-1 of DMP, DEP, DBP or a mixture containing 100mg L-1 of each within 30h. Metabolites were not detected by HPLC or LC-MS analyses. Biodegradation of phthalate esters followed first-order kinetics. The rates of biodegradation of individual esters followed the order DEP>DBP>DMP while in the mixture, rates followed DEP>DMP>DBP. Results obtained suggested that the isolated Variovorax species was highly efficient in biodegrading DMP, DEP, DBP or their mixture.

Biodegradation of Dimethyl Phthalate, Diethyl Phthalate, Dibutyl Phthalate and Their Mixture by VariovoraxSp

Biodegradation of dimethyl phthalate (DMP), diethyl phthalate (DEP) and dibutyl phthalate (DBP) and their mixture by a bacterial strain is reported. The strain was isolated by enrichment technique from garbage dumped soil nearby Indian Institute of Technology Bombay. The isolate had the ability to utilize mixture of DMP, DEP and DBP in the growth medium as well as the individual phthalate esters as the sole source of carbon and energy. The bacterial isolate was identified as Variovorax sp. based on 16S r-DNA sequence analysis. Variovorax sp. degraded >99% of 300 mg/l of DMP, DEP, DBP or a mixture containing 100 mg/l of each within 30 h. Metabolites or end products were not detected by HPLC analyses. Biodegradation of phthalate esters followed first-order kinetics. The rates of biodegradation of individual esters followed the order: DEP>DBP>DMP while in the mixture, rates followed the order: DEP>DMP>DBP. Crude cell free extracts prepared from bacterial isolates contained cocktail of inducible enzymes responsible for the degradation of DMP or DEP.

Biodegradation of phthalate esters in compost-amended soil

In this study, we investigated the biodegradation of the phthalate acid esters (PAEs) di- n-butyl phthalate (DBP) and di-(2-ethyl hexyl) phthalate (DEHP) in compost and compost-amended soil. DBP (50 mg kg −1) and DEHP (50 mg kg −1) were added to the two types of compost (straw and animal manure) and subsequently added to the soil; they were tested as a single compound and in combination. Optimal PAE degradation in soil was at pH 7 and 30 °C. The degradation of PAE was enhanced when DBP and DEHP were simultaneously present in the soil. The addition of either of the two types of compost individually also improved the rate of PAE degradation. Compost samples were separated into fractions with various particle size ranges, which spanned from 0.1–0.45 to 500–2000 μm. We observed that the compost fractions with smaller particle sizes demonstrated higher PAE degradation rates. When the different compost fractions were added to soil, however, compost particle size had no significant effect on the rate of PAE degradation.

Biodegradation of phthalate esters by two bacteria strains

In this study two aerobic phthalic acid ester (PAE) degrading bacteria strains, DK4 and O18, were isolated from river sediment and petrochemical sludge, respectively. The two strains were found to rapidly degrade PAE with shorter alkyl-chains such diethyl phthalate (DEP), dipropyl phthalate (DPrP), di- n-butyl phthalate (DBP), benzylbutyl phthalate (BBP) and diphenyl phthalate (DPP) are very easily biodegraded, while PAE with longer alkyl-chains such as dicyclohexyl phthalate (DCP) and dihexyl phthalate (DHP) and di-(2-ethylhexyl) phthalate (DEHP) are poorly degraded. The degradation rates of the eight PAEs were higher for strain DK4 than for strain O18. In the simultaneous presence of strains DK4 and O18, the degradation rates of the eight PAEs examined were enhanced. When the eight PAEs were present simultaneously, degradation rates were also enhanced. We also found that PAE degradation was delayed by the addition of nonylphenol or selected polycyclic aromatic hydrocarbons (PAHs) at a concentration of 1 μg/g in the sediment. The bacteria strains isolated, DK4 and O18, were identified as Sphigomonas sp. and Corynebacterium sp., respectively.

Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge

Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants. Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge. To date, many studies exist on the anaerobic biodegradation rates of PAE, especially of the easily biodegradable ones, whereas the higher molecular weight PAE have reported to be non-biodegradable under methanogenic conditions. Furthermore, there is no information on the effect of the PAE on the performance of the anaerobic digesters treating sludge. In this study, the anaerobic biodegradation of di- n-butyl phthalate (DBP), di-ethyl phthalate (DEP) and di-ethylhexyl phthalate (DEHP) was investigated and their relative rates of anaerobic degradation were calculated. Also, the biological removal of PAE during the anaerobic digestion of sludge in bench-scale digesters was investigated using DBP and DEHP as model compounds of one biodegradable and one recalcitrant PAE respectively. The degradation of all the PAE tested in this study (DEP, DBP and DEHP) is adequately described by first-order kinetics. Batch and continuous experiments showed that DEP and DBP present in sludge are rapidly degraded under mesophilic anaerobic conditions (a first-order kinetic constant of 8.04 × 10 −2 and 13.69 × 10 −2–4.35 day −1 respectively) while DEHP is degraded at a rate between one to two orders of magnitude lower (0.35 × 10 −2–3.59 × 10 −2 day −1). It is of high significance that experiments with anaerobic sludge of different origin (US and Europe) showed that degradation of DEHP occurs under methanogenic conditions. Accumulation of high levels of DEHP (more than 60 mg/l) in the anaerobic digester has a negative effect on DBP and DEHP removal rates as well as on the biogas production.

固定化菌体によるフタル酸エステル類の分解

固定化菌体によるフタル酸エステル類の分解

The effect of biodegradation on the determination of some chemodynamic properties of phthalate esters

Abstract Initial efforts to determine some chemodynamic properties of three phthalate esters (PEs) in soil‐water systems gave erratic results. This behavior can be explained by the occurrence of biodegradation of PEs over time scales encountered in laboratory investigations. Results are presented which demonstrate that biodegradation can be significant in the laboratory and should be controlled.