Cloning and functional characterization of the styE gene, involved in styrene transport in Pseudomonas putida CA-3

Insights into plastic biodegradation: community composition and functional capabilities of the superworm (Zophobas morio) microbiome in styrofoam feeding trials

Plastics are inexpensive and widely used organic polymers, but their high durability hinders biodegradation. Polystyrene, including extruded polystyrene (also known as styrofoam), is among the most commonly produced plastics worldwide and is recalcitrant to microbial degradation. In this study, we assessed changes in the gut microbiome of superworms (Zophobas morio) reared on bran, polystyrene or under starvation conditions over a 3 weeks period. Superworms on all diets were able to complete their life cycle to pupae and imago, although superworms reared on polystyrene had minimal weight gains, resulting in lower pupation rates compared to bran reared worms. The change in microbial gut communities from baseline differed considerably between diet groups, with polystyrene and starvation groups characterized by a loss of microbial diversity and the presence of opportunistic pathogens. Inferred microbial functions enriched in the polystyrene group included transposon movements, membrane restructuring and adaptations to oxidative stress. We detected several encoded enzymes with reported polystyrene and styrene degradation abilities, supporting previous reports of polystyrene-degrading bacteria in the superworm gut. By recovering metagenome-assembled genomes (MAGs) we linked phylogeny and functions and identified genera including Pseudomonas, Rhodococcus and Corynebacterium that possess genes associated with polystyrene degradation. In conclusion, our results provide the first metagenomic insights into the metabolic pathways used by the gut microbiome of superworms to degrade polystyrene. Our results also confirm that superworms can survive on polystyrene feed, but this diet has considerable negative impacts on host gut microbiome diversity and health.

P, S. CF, A. G. Exploring the styrene metabolism by aerobic bacterial isolates for the effective management of leachates in an aqueous system

In the present study, the styrene metabolic profile of three aerobic bacterial isolates explored in a batch mode study. The isolates found application in the management of elachates in the waste dump yard. These three bacterial species have different origins and were studied as a single and mixed consortia. The Lysinibacillus strain M01 (from marine sources), Lysinibacillus strain WD03 (from a waste dump yard), and Pseudomonas strain BG07 (from bovine gut) were used in the present study. The styrene concentration was fixed in the range between 0.5 and 1.5 mL L⁻¹. The metabolites obtained upon microbial degradation were assessed using high-performance liquid chromatography (HPLC), UV-visible spectroscopy, and FTIR spectroscopy (Fourier transform infrared spectroscopy). Furthermore, the genes (Sty A, B, C, D, and E) responsible for the degradation of styrene by the three abovementioned isolates were identified using PCR with respective designed primers. Instrumental analyses revealed the presence of phenylacetic acid (PAA) at significant levels in the growth medium after the scheduled experimental period and confirmed the metabolism of styrene by the chosen isolates. Compared to the case of individual cultures, the results of the mixed consortia support the metabolism of styrene at appreciable levels. The present study provides a suitable biological solution for the management of leachates containing styrene and a way to achieve industrially important chemicals (PAA) through a microbially mediated process.

Profile of the three potential aerobic bacterial isolates responsible for the metabolism of styrene.

On the Enigma of Glutathione-Dependent Styrene Degradation in Gordonia rubripertincta CWB2

Among bacteria, only a single styrene-specific degradation pathway has been reported so far. It comprises the activity of styrene monooxygenase, styrene oxide isomerase, and phenylacetaldehyde dehydrogenase, yielding phenylacetic acid as the central metabolite. The alternative route comprises ring-hydroxylating enzymes and yields vinyl catechol as central metabolite, which undergoes meta-cleavage. This was reported to be unspecific and also allows the degradation of benzene derivatives. However, some bacteria had been described to degrade styrene but do not employ one of those routes or only parts of them. Here, we describe a novel "hybrid" degradation pathway for styrene located on a plasmid of foreign origin. As putatively also unspecific, it allows metabolizing chemically analogous compounds (e.g., halogenated and/or alkylated styrene derivatives). Gordonia rubripertincta CWB2 was isolated with styrene as the sole source of carbon and energy. It employs an assembled route of the styrene side-chain degradation and isoprene degradation pathways that also funnels into phenylacetic acid as the central metabolite. Metabolites, enzyme activity, genome, transcriptome, and proteome data reinforce this observation and allow us to understand this biotechnologically relevant pathway, which can be used for the production of ibuprofen.IMPORTANCE The degradation of xenobiotics by bacteria is not only important for bioremediation but also because the involved enzymes are potential catalysts in biotechnological applications. This study reveals a novel degradation pathway for the hazardous organic compound styrene in Gordonia rubripertincta CWB2. This study provides an impressive illustration of horizontal gene transfer, which enables novel metabolic capabilities. This study presents glutathione-dependent styrene metabolization in an (actino-)bacterium. Further, the genomic background of the ability of strain CWB2 to produce ibuprofen is demonstrated.

Benzoate transport in Pseudomonas putida CSV86

Pseudomonas putida strain CSV86 metabolizes variety of aromatic compounds as the sole carbon source. Genome analysis revealed the presence of genes encoding putative transporters for benzoate, p-hydroxybenzoate, phenylacetate, p-hydroxyphenylacetate and vanillate. Bioinformatic analysis revealed that benzoate transport and metabolism genes are clustered at the ben locus as benK-catA-benE-benF. Protein topology prediction suggests that BenK (aromatic acid-H+ symporter of major facilitator superfamily) has 12 transmembrane α-helices with the conserved motif LADRXGRKX in loop 2, while BenE (benzoate-H+ symporter protein) has 11 predicted transmembrane α-helices. benF and catA encode benzoate specific porin, OprD and catechol 1,2-dioxygenase, respectively. Biochemical studies suggest that benzoate was transported by an inducible and active process. Inhibition (90%-100%) in the presence of dinitrophenol suggests that the energy for the transport process is derived from the proton motive force. The maximum rate of benzoate transport was 484 pmole min-1 mg-1 cells with an affinity constant, Kmof 4.5 μM. Transcriptional analysis of the benzoate and glucose-grown cells showed inducible expression of benF, benK and benE, suggesting that besides outer membrane porin, both inner membrane transporters probably contribute for the benzoate transport in P. putida strain CSV86.

Salt Adaptation and Evolutionary Implication of a Nah-related PAHs Dioxygenase cloned from a Halophilic Phenanthrene Degrading Consortium

Polycyclic aromatic hydrocarbons (PAHs) pollutions often occur in marine and other saline environment, largely due to anthropogenic activities. However, study of the PAHs-degradation genotypes in halophiles is limited, compared with the mesophilic terrestrial PAHs degraders. In this study, a bacterial consortium (CY-1) was enriched from saline soil contaminated with crude oil using phenanthrene as the sole carbon source at 10% salinity. CY-1 was dominated by the moderate halophilic Marinobacter species, and its dominant PAHs ring-hydroxylating dioxygenase (RHD) genotypes shared high identity to the classic nah-related RHDs found in the mesophilic species. Further cloning of a 5.6-kb gene cluster from CY-1 unveiled the existence of a new type of PAHs degradation gene cluster (hpah), which most probably evolves from the nah-related gene clusters. Expression of the RHD in this gene cluster in E. coli lead to the discovery of its prominent salt-tolerant properties compared with two RHDs from mesophiles. As a common structural feature shared by all halophilic and halotolerant enzymes, higher abundance of acidic amino acids was also found on the surface of this RHD than its closest nah-related alleles. These results suggest evolution towards saline adaptation occurred after horizontal transfer of this hpah gene cluster into the halophiles.

Functional characterization of a StyS sensor kinase reveals distinct domains associated with intracellular and extracellular sensing of styrene in P. putida CA-3

Bacterial two-component systems (TCSs) are of vital importance in the translation of rapidly changing environmental conditions into appropriate cellular regulatory responses enabling adaptation, growth, and survival. The diverse range of environmental signals that TCSs can process, coupled with discrete modular domains within TCS proteins, offers considerable potential for the rational design of bio-sensor and/or bio-reporter strains. In this study we functionally characterize the multi-domain StyS sensor kinase associated with sensing of the aromatic pollutant styrene by Pseudomonas putida CA-3. Deletion analysis of discrete domains was performed and the ability of the truncated StyS sensor proteins to activate a cognate reporter system in an E. coli host assessed. The essential histidine kinase and PAS input domains were identified for StyS dependent activation of the reporter system. However, co-expression of an ABC-transporter protein StyE, previously linked to styrene transport in P. putida CA-3, enabled activation of the reporter system with a StyS construct containing a non-essential PAS input domain, suggesting a novel role for intracellular detection and/or activation. Site directed mutagenesis and amino acid deletions were employed to further characterize the PAS sensing domains of both input regions. The potential implications of these findings in the use of multi-domain sensor kinases in rational design strategies and the potential link between transport and intracellular sensing are discussed.

Enzymes and genes involved in aerobic alkane degradation

Alkanes are major constituents of crude oil. They are also present at low concentrations in diverse non-contaminated because many living organisms produce them as chemo-attractants or as protecting agents against water loss. Alkane degradation is a widespread phenomenon in nature. The numerous microorganisms, both prokaryotic and eukaryotic, capable of utilizing alkanes as a carbon and energy source, have been isolated and characterized. This review summarizes the current knowledge of how bacteria metabolize alkanes aerobically, with a particular emphasis on the oxidation of long-chain alkanes, including factors that are responsible for chemotaxis to alkanes, transport across cell membrane of alkanes, the regulation of alkane degradation gene and initial oxidation.

MhbT is a specific transporter for 3-hydroxybenzoate uptake by Gram-negative bacteria

Klebsiella pneumoniae M5a1 is capable of utilizing 3-hydroxybenzoate via gentisate, and the 6.3-kb gene cluster mhbRTDHIM conferred the ability to grow on 3-hydroxybenzoate to Escherichia coli and Pseudomonas putida PaW340. Four of the six genes (mhbDHIM) encode enzymes converting 3-hydroxybenzoate to pyruvate and fumarate via gentisate. MhbR is a gene activator, and MhbT is a hypothetical protein belonging to the transporter of the aromatic acid/H(+) symporter family. Since a transporter for 3-hydrxybenzoate uptake has not been characterized to date, we investigated whether MhbT is responsible for the uptake of 3-hydroxybenzoate, its metabolic intermediate gentisate, or both. The MhbT-green fluorescent protein (GFP) fusion protein was located on the cytoplasmic membrane. P. putida PaW340 containing mhbRΔTDHIM could not grow on 3-hydroxybenzoate; however, supplying mhbT in trans allowed the bacterium to grow on the substrate. K. pneumoniae M5a1 and P. putida PaW340 containing recombinant MhbT transported (14)C-labeled 3-hydroxybenzoate but not (14)C-labeled gentisate and benzoate into the cells. Site-directed mutagenesis of two conserved amino acid residues (Asp-82 and Asp-314) and a less-conserved residue (Val-311) among the members of the symporter family in the hydrophilic cytoplasmic loops resulted in the loss of 3-hydroxybenzoate uptake by P. putida PaW340 carrying the mutant proteins. Hence, we demonstrated that MhbT is a specific 3-hydroxybenzoate transporter.

Regulation of phenylacetic acid uptake is σ54 dependent in Pseudomonas putida CA-3

Background

Styrene is a toxic and potentially carcinogenic alkenylbenzene used extensively in the polymer processing industry. Significant quantities of contaminated liquid waste are generated annually as a consequence. However, styrene is not a true xenobiotic and microbial pathways for its aerobic assimilation, via an intermediate, phenylacetic acid, have been identified in a diverse range of environmental isolates. The potential for microbial bioremediation of styrene waste has received considerable research attention over the last number of years. As a result the structure, organisation and encoded function of the genes responsible for styrene and phenylacetic acid sensing, uptake and catabolism have been elucidated. However, a limited understanding persists in relation to host specific regulatory molecules which may impart additional control over these pathways. In this study the styrene degrader Pseudomonas putida CA-3 was subjected to random mini-Tn5 mutagenesis and mutants screened for altered styrene/phenylacetic acid utilisation profiles potentially linked to non-catabolon encoded regulatory influences.

Results

One mutant, D7, capable of growth on styrene, but not on phenylacetic acid, harboured a Tn5 insertion in the rpoN gene encoding σ54. Complementation of the D7 mutant with the wild type rpoN gene restored the ability of this strain to utilise phenylacetic acid as a sole carbon source. Subsequent RT-PCR analyses revealed that a phenylacetate permease, PaaL, was expressed in wild type P. putida CA-3 cells utilising styrene or phenylacetic acid, but could not be detected in the disrupted D7 mutant. Expression of plasmid borne paaL in mutant D7 was found to fully restore the phenylacetic acid utilisation capacity of the strain to wild type levels. Bioinformatic analysis of the paaL promoter from P. putida CA-3 revealed two σ⁵⁴ consensus binding sites in a non-archetypal configuration, with the transcriptional start site being resolved by primer extension analysis. Comparative analyses of genomes encoding phenylacetyl CoA, (PACoA), catabolic operons identified a common association among styrene degradation linked PACoA catabolons in Pseudomonas species studied to date.

Conclusions

In summary, this is the first study to report RpoN dependent transcriptional activation of the PACoA catabolon paaL gene, encoding a transport protein essential for phenylacetic acid utilisation in P. putida CA-3. Bioinformatic analysis is provided to suggest this regulatory link may be common among styrene degrading Pseudomonads.

Isolation and characterization of styrene metabolism genes from styrene-assimilating soil bacteria Rhodococcus sp. ST-5 and ST-10

Styrene metabolism genes were isolated from styrene-assimilating bacteria Rhodococcus sp. ST-5 and ST-10. Strain ST-5 had a gene cluster containing four open reading frames which encoded styrene degradation enzymes. The genes showed high similarity to styABCD of Pseudomonas sp. Y2. On the other hand, strain ST-10 had only two genes which encoded styrene monooxygenase and flavin oxidoreductase (styAB). Escherichia coli transformants possessing the sty genes of strains ST-5 and ST-10 produced (S)-styrene oxide from styrene, indicating that these genes function as styrene degradation enzymes. Metabolite analysis by resting-cell reaction with gas chromatography-mass spectrometry revealed that strain ST-5 converts styrene to phenylacetaldehyde via styrene oxide by styrene oxide isomerase (styC) reaction. On the other hand, strain ST-10 lacked this enzyme, and thus accumulated styrene oxide as an intermediate. HPLC analysis showed that styrene oxide was spontaneously isomerized to phenylacetaldehyde by chemical reaction. The produced phenylacetaldehyde was converted to phenylacetic acid (PAA) in strain ST-10 as well as in strain ST-5. Furthermore, phenylacetic acid was converted to phenylacetyl-CoA by the catalysis of phenylacetate-CoA ligase in strains ST-5 and ST-10. This study proposes possible styrene metabolism pathways in Rhodococcus sp. strains ST-5 and ST-10.

A beta-barrel outer membrane protein facilitates cellular uptake of polychlorophenols in Cupriavidus necator

The tcpRXABCYD operon of Cupriavidus necator JMP134 is involved in the degradation of 2,4,6-trichlorophenol (TCP). All of the gene products except TcpY have assigned functions in TCP metabolism. Sequence comparison identified TcpY as a member of COG4313, a group of hypothetical proteins. TcpY has a signal peptide, indicating it is a membrane or secreted protein. Secondary structure and topology analysis indicated TcpY as a beta-barrel outer membrane protein, similar to the Escherichia coli outer membrane protein FadL that transports hydrophobic long-chain fatty acids. Constitutive expression of tcpY in two C. necator strains rendered the cells more sensitive to TCP and other polychlorophenols. Further, C. necator JMP134 expressing cloned tcpY transported more TCP into the cell than a control with the cloning vector. Thus, TcpY is an outer membrane protein that facilitates the passing of polychlorophenols across the outer membrane of C. necator. Similarly, other COG4313 proteins are possibly outer membrane transporters of hydrophobic aromatic compounds.

Analysis of the Pseudomonas putida CA-3 proteome during growth on styrene under nitrogen-limiting and non-limiting conditions

Pseudomonas putida CA-3 is a styrene-degrading bacterium capable of accumulating medium-chain-length polyhydroxyalkanoate (mclPHA) when exposed to limiting concentrations of a nitrogen source in the growth medium. Using shotgun proteomics we analysed global proteome expression in P. putida CA-3 supplied with styrene as the sole carbon and energy source under N-limiting (condition permissive for mclPHA synthesis) and non-limiting (condition non-permissive for mclPHA accumulation) growth conditions in order to provide insight into the molecular response of P. putida CA-3 to limitation of nitrogen when grown on styrene. A total of 1761 proteins were identified with high confidence and the detected proteins could be assigned to functional groups including styrene degradation, energy, nucleotide metabolism, protein synthesis, transport, stress response and motility. Proteins involved in the upper and lower styrene degradation pathway were expressed throughout the 48 h growth period under both nitrogen limitation and excess. Proteins involved in polyhydroxyalkanoate (PHA) biosynthesis, nitrogen assimilation and amino acid transport, and outer membrane proteins were upregulated under nitrogen limitation. PHA accumulation and biosynthesis were only expressed under nitrogen limitation. Nitrogen assimilation proteins were detected on average at twofold higher amounts under nitrogen limitation. Expression of the branched-chain amino acid ABC transporter was up to 16-fold higher under nitrogen-limiting conditions. Branched chain amino acid uptake by nitrogen-limited cultures was also higher than that by non-limited cultures. Outer membrane lipoproteins were expressed at twofold higher levels under nitrogen limitation. This was confirmed by Western blotting (immunochemical detection) of cells grown under nitrogen limitation. Our study provides the first global description of protein expression changes during growth of any organism on styrene and accumulating mclPHA (nitrogen-limited growth).

Strain of Fusarium oxysporum isolated from almond hulls produces styrene and 7-methyl-1,3,5-cyclooctatriene as the principal volatile components

An isolated strain of Fusarium oxysporum from the hulls of Prunus dulcis (sweet almond) was found to produce relatively large quantities of the hydrocarbons styrene and two isomers of 7-methyl-1,3,5- cyclooctatriene (MCOT). Production of styrene and MCOT was reproduced on a small scale using potato dextrose agar as a growth medium and scaled up using 1 L of inoculated potato dextrose broth. The compounds were trapped as volatile organic compounds (VOCs) onto solid-phase microextraction (SPME) for small scale and Tenax for large scale and then isolated using standard high-performance liquid chromatography (HPLC) methods. Styrene was authenticated by a comparison to the retention times, fragmentation patterns, and calculated retention indices of a commercially available sample. The identity of MCOT was verified by a short chemical synthesis and a comparison of spectroscopic data to the isolated sample. A biosynthetic scheme of styrene is proposed on the basis of a (13)C-labeling study. This is the first report of MCOT isolated as a natural product.

The interplay of StyR and IHF regulates substrate-dependent induction and carbon catabolite repression of styrene catabolism genes in Pseudomonas fluorescens ST

Background

In Pseudomonas fluorescens ST, the promoter of the styrene catabolic operon, PstyA, is induced by styrene and is subject to catabolite repression. PstyA regulation relies on the StyS/StyR two-component system and on the IHF global regulator. The phosphorylated response regulator StyR (StyR-P) activates PstyA in inducing conditions when it binds to the high-affinity site STY2, located about -40 bp from the transcription start point. A cis-acting element upstream of STY2, named URE, contains a low-affinity StyR-P binding site (STY1), overlapping the IHF binding site. Deletion of the URE led to a decrease of promoter activity in inducing conditions and to a partial release of catabolite repression. This study was undertaken to assess the relative role played by IHF and StyR-P on the URE, and to clarify if PstyA catabolite repression could rely on the interplay of these regulators.

Results

StyR-P and IHF compete for binding to the URE region. PstyA full activity in inducing conditions is achieved when StyR-P and IHF bind to site STY2 and to the URE, respectively. Under catabolite repression conditions, StyR-P binds the STY1 site, replacing IHF at the URE region. StyR-P bound to both STY1 and STY2 sites oligomerizes, likely promoting the formation of a DNA loop that closes the promoter in a repressed conformation. We found that StyR and IHF protein levels did not change in catabolite repression conditions, implying that PstyA repression is achieved through an increase in the StyR-P/StyR ratio.

Conclusion

We propose a model according to which the activity of the PstyA promoter is determined by conformational changes. An open conformation is operative in inducing conditions when StyR-P is bound to STY2 site and IHF to the URE. Under catabolite repression conditions StyR-P cellular levels would increase, displacing IHF from the URE and closing the promoter in a repressed conformation. The balance between the open and the closed promoter conformation would determine a fine modulation of the promoter activity. Since StyR and IHF protein levels do not vary in the different conditions, the key-factor regulating PstyA catabolite repression is likely the kinase activity of the StyR-cognate sensor protein StyS.

Identification and characterization of genes encoding a putative ABC-type transporter essential for utilization of gamma-hexachlorocyclohexane in Sphingobium japonicum UT26

Sphingobium japonicum UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH) as its sole source of carbon and energy. In our previous studies, we cloned and characterized genes encoding enzymes for the conversion of gamma-HCH to beta-ketoadipate in UT26. In this study, we analyzed a mutant obtained by transposon mutagenesis and identified and characterized new genes encoding a putative ABC-type transporter essential for the utilization of gamma-HCH in strain UT26. This putative ABC transporter consists of four components, permease, ATPase, periplasmic protein, and lipoprotein, encoded by linK, linL, linM, and linN, respectively. Mutation and complementation analyses indicated that all the linKLMN genes are required, probably as a set, for gamma-HCH utilization in UT26. Furthermore, the mutant cells deficient in this putative ABC transporter showed (i) higher gamma-HCH degradation activity and greater accumulation of the toxic dead-end product 2,5-dichlorophenol (2,5-DCP), (ii) higher sensitivity to 2,5-DCP itself, and (iii) higher permeability of hydrophobic compounds than the wild-type cells. These results strongly suggested that LinKLMN are involved in gamma-HCH utilization by controlling membrane hydrophobicity. This study clearly demonstrated that a cellular factor besides catabolic enzymes and transcriptional regulators is essential for utilization of xenobiotic compounds in bacterial cells.

Effect of heterologous expression ofphaG[(R)-3-hydroxyacyl-ACP-CoA transferase] on polyhydroxyalkanoate accumulation from the aromatic hydrocarbon phenylacetic acid inPseudomonasspecies

Five Pseudomonas strains capable of growth with the aromatic carboxylic acid phenylacetic acid were investigated with a view to improving PHA accumulation. The overexpression of (R)-3-hydroxyacyl-ACP-CoA transferase (PhaG) from Pseudomonas putida CA-3 increased PHA accumulation in only one of the five strains tested, namely Pseudomonas jessenii C8. Recombinant P. jessenii C8 harbouring the phaG gene showed a 4.1-fold increase (9.6-39% cell dry weight) in PHA accumulation when grown on phenylacetic acid (15 mM) compared with the wild-type strain. This is the highest reported level of PHA accumulation from phenylacetic acid. This is also the first time the heterologous expression of phaG has resulted in improved PHA accumulation from an aromatic carbon source. The growth patterns of the wild type and recombinant strains were very similar, with no significant differences observed in carbon and nitrogen utilization.

4-Chlorobenzoate uptake in Comamonas sp. strain DJ-12 is mediated by a tripartite ATP-independent periplasmic transporter

The fcb gene cluster involved in the hydrolytic dehalogenation of 4-chlorobenzoate is organized in the order fcbB-fcbA-fcbT1-fcbT2-fcbT3-fcbC in Comamonas sp. strain DJ-12. The genes are operonic and inducible with 4-chloro-, 4-iodo-, and 4-bromobenzoate. The fcbT1, fcbT2, and fcbT3 genes encode a transporter in the secondary TRAP (tripartite ATP-independent periplasmic) family. An fcbT1T2T3 knockout mutant shows a much slower growth rate on 4-chlorobenzoate compared to the wild type. 4-Chlorobenzoate is transported into the wild-type strain five times faster than into the fcbT1T2T3 knockout mutant. Transport of 4-chlorobenzoate shows significant inhibition by 4-bromo-, 4-iodo-, and 4-fluorobenzoate and mild inhibition by 3-chlorobenzoate, 2-chlorobenzoate, 4-hydroxybenzoate, 3-hydroxybenzoate, and benzoate. Uptake of 4-chlorobenzoate is significantly inhibited by ionophores which collapse the proton motive force.

Microbial degradation of styrene: biochemistry, molecular genetics, and perspectives for biotechnological applications

Large quantities of the potentially toxic compound styrene are produced and used annually by the petrochemical and polymer-processing industries. It is as a direct consequence of this that significant volumes of styrene are released into the environment in both the liquid and the gaseous forms. Styrene and its metabolites are known to have serious negative effects on human health and therefore, strategies to prevent its release, remove it from the environment, and understand its route of degradation were the subject of much research. There are a large number of microbial genera capable of metabolizing styrene as a sole source of carbon and energy and therefore, the possibility of applying these organisms to bioremediation strategies was extensively investigated. From the multitude of biodegradation studies, the application of styrene-degrading organisms or single enzymes for the synthesis of value-added products such as epoxides has emerged.