Ferulic Acid Degradation Research Articles

Effects of temperature and solvent polarity on the thermodynamic and photophysical properties of ferulic acid using density functional theory (DFT)

Ferulic acid (FA) possesses diverse biological properties and is extensively utilized in pharmaceuticals, cosmetics, and the food industry due to its non-toxic nature. However, environmental factors such as temperature and solvent polarity play a significant role in influencing the thermodynamic and photophysical properties of drugs, particularly during the drug optimization and design phases. This study investigates the impact of temperature and solvent polarity on the thermodynamic and optical properties of FA using density functional theory (DFT) with the B3LYP functional approach and the 6-311++G(d, p) basis set under various solvent and gas conditions. Additionally, vertical UV-vis absorption and emission spectra of FA in different solvent polarities and gas phases were analyzed using time-dependent density-functional theory (TDDFT) with the B3LYP method and the 6-31++G(d, p) basis set. Applying Koopman's theory, the chemical activity of FA was assessed based on the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) values. The findings indicate that an increase in temperature within the range of 100–1000 K leads to elevated enthalpy, heat capacity, and entropy due to molecular vibrational activity, resulting in FA degradation and instability. Furthermore, thermodynamic parameters, HOMO and LUMO values, and the chemical activity of FA were also influenced by different solvent polarities. The absorption and emission spectra of FA exhibited a red shift due to interactions with solvents and solutes. Overall, this study analyzed the significance of environmental factors such as temperature and solvent polarity in pharmaceutical design and optimization processes to enhance drug efficacy and stability.

Degradation of Lignin Pollutants by Persulfate Activated with a Graphene Oxide Loaded Cu2(OH)3NO3 Composite

AbstractGraphene oxide (GO)‐Cu2(OH)3NO3 composite was prepared by a thermal calcination process and evaluated as an effective heterogeneous catalytic material. The composite displayed prominent activated performance to persulfate, which was influenced by preparation condition and the reaction parameters in catalytic system. Under optimal reactive conditions, the GO‐Cu2(OH)3NO3 composite yielded rapid degradation of ferulic acid, which the corresponding apparent rate constant was 1.12×10−1 min−1. Catalytic mechanism analysis showed that the main oxygen species were ⋅SO4− and ⋅OH. Among them, ⋅OH made the main contribution in the catalytic system. The analysis of degradation intermediates of ferulic acid showed that the compound could be mineralized to small molecules. The remarkable enhanced heterogeneous catalytic performance of GO‐Cu2(OH)3NO3 was due to a larger specific surface area, high adsorption capacity and a high mass transfer efficiency of oxidizing radicals in the reactive system.

Bioconversion of ferulic acid and vanillin to vanillic acid by cold-adapted Paraburkholderia aromaticivorans AR20-38: impact of culture conditions

PurposeBiovalorization of lignin-derived aromatic monomers such as ferulic acid (FA) has attracted considerable interest. The cold-adapted strain Paraburkholderia aromaticivorans AR20-38 converts FA to the value-added product vanillic acid (VA), without further VA degradation. The efficiency of the bioconversion of FA to VA was optimized by studying culture conditions.MethodsVarious cultivation parameters (agitation, temperature, FA concentration, nutrient supplementation) were assessed to increase biomass production and shorten the cultivation time, while obtaining high VA production yields. The fate of the intermediate vanillin was also studied. Lignin monomers and degradation products (FA, vanillin, VA) were quantified via UV/Vis-HPLC.ResultFull bioconversion of 5 mM FA occurred over a broad temperature range of 5–30 °C. Concentrations up 30 mM FA were utilized as the sole carbon source at 20 °C. Molar VA yields (> 90%) produced from 5 to 12.5 mM FA and from 15 to 17.5 mM FA (82–87%) were not significantly different at 10 °C and 20 °C. The supplementation of the mineral medium with monosaccharides (glucose, fructose, mannose) and/or N-rich complex compounds (yeast extract, casamino acids) resulted in high biomass production, accelerated FA bioconversion, and high molar yields (96–100%). The presence of the N-rich compounds alone or in combination with glucose reduced the incubation time necessary to convert FA to VA. Vanillin, formed as an intermediate during FA degradation, was consumed and converted to VA before FA metabolization, when added in combination with FA. Vanillin bioconversion was significantly accelerated in the presence of glucose.ConclusionThe variation of culture conditions improved the efficiency of the studied strain to convert FA via vanillin to VA and demonstrated remarkable FA bioconversion under varying environmental conditions, especially temperature, substrate concentration, and nutrient availability, which is of importance for potential future application.

Degradation of ferulic acid and caffeic acid by dielectric barrier discharge plasma combined with Mn/CoOOH/activated carbon fiber

Organic pollutants of olive mill wastewater (OMW) have caused various negative effect to water environments. It is imperative to develop an effective technology for eliminating organic pollutants in OMW. In this study, representative organic pollutants in OWM, ferulic acid (FA) and caffeic acid (CA), were removed from water by dielectric barrier discharge (DBD) plasma and Mn/CoOOH/activated carbon fiber (ACF) catalyst. The treatment performance and catalytic mechanisms were studied. The results show that the combined system could effectively remove FA and CA. For example, FA and CA degradation efficiency was 81.6% and 94.2% in the 20 L of mixed wastewater with the 100 min treatment using DBD combined with Mn/CoOOH/ACF. Experiments and density functional theory (DFT) calculations indicate that the electron transfer from the catalyst to antibonding orbits of O3 and H2O2 caused the dissociated adsorption, promoting the transformation of O3 and H2O2 to ·O, singlet oxygen and ·OH. Additionally, the doping of Mn in CoOOH benefited the electron transfer because Mn had a higher d-band center than Co in Mn/CoOOH, which was conducive to the interaction of O3 and H2O2 with the catalyst. The possible degradation pathways of FA and CA were proposed.

In Situ Rumen Degradation Characteristics and Bacterial Colonization of Corn Silages Differing in Ferulic and p-Coumaric Acid Contents.

In plant cell wall, ferulic acid (FA) and p-coumaric acid (pCA) are commonly linked with arabinoxylans and lignin through ester and ether bonds. These linkages were deemed to hinder the access of rumen microbes to cell wall polysaccharides. The attachment of rumen microbes to plant cell wall was believed to have profound effects on the rate and the extent of forage digestion in rumen. The objective of this study was to evaluate the effect of bound phenolic acid content and their composition in corn silages on the nutrient degradability, and the composition of the attached bacteria. Following an in situ rumen degradation method, eight representative corn silages with different FA and pCA contents were placed into nylon bags and incubated in the rumens of three matured lactating Holstein cows for 0, 6, 12, 24, 36, 48, and 72 h, respectively. Corn silage digestibility was assessed by in situ degradation methods. As a result, the effective degradability of dry matter, neutral detergent fibre, and acid detergent fibre were negatively related to the ether-linked FA and pCA, and their ratio in corn silages, suggesting that not only the content and but also the composition of phenolic acids significantly affected the degradation characteristics of corn silages. After 24 h rumen fermentation, Firmicutes, Actinobacteria, and Bacteroidota were observed as the dominant phyla in the bacterial communities attached to the corn silages. After 72 h rumen fermentation, the rumen degradation of ester-linked FA was much greater than that of ester-linked pCA. The correlation analysis noted that Erysipelotrichaceae_UCG-002, Olsenella, Ruminococcus_gauvreauii_group, Acetitomaculum, and Bifidobacterium were negatively related to the initial ether-linked FA content while Prevotella was positively related to the ether-linked FA content and the ratio of pCA to FA. In summary, the present results suggested that the content of ether-linked phenolic acids in plant cell walls exhibited a more profound effect on the pattern of microbial colonization than the fibre content.

Photocatalytic activity of Eu-doped ZnO prepared by supercritical antisolvent precipitation route: When defects become virtues

• Eu-doped ZnO at different Eu content were synthetized by SAS process. • Eu-doped ZnO provides novel defect sites and higher hydrophilicity. • Photocatalytic activity was assessed under UV light. • The optimal Eu content for crystal violet and ferulic acid degradation was 1 mol%. • A lower hydrophilicity induced a higher vanillin selectivity. The aim of this work is to determine the structural and optical properties of Eu-doped ZnO powders prepared by supercritical antisolvent precipitation route (SAS) and to correlate the physico-chemical features with the photocatalytic activity under UV light. Raman and EPR spectroscopy highlight the introduction of novel defects (mainly singly and doubly ionized oxygen vacancies, and oxygen interstitials) on the Eu-doped ZnO samples, which confer higher hydrophilicity to the doped samples with respect to bare ZnO, as evidenced by FT-IR analysis. Additionally, photoluminescence spectra show that the presence of Eu 3+ totally quenches the visible light emission typical of bare ZnO, which mainly results from the recombination of photogenerated holes at defective sites. The prepared samples were tested both for the photocatalytic degradation of crystal violet dye (CV) and for the partial oxidation of ferulic acid under UV irradiation. The photocatalytic activity results evidence of a higher ability of Eu-doped photocatalysts to degrade CV and ferulic acid, while higher selectivity values towards vanillin are obtained in the presence of bare ZnO. The higher activity of Eu-doped ZnO photocatalysts is linked to the stabilization of photogenerated holes and to their higher hydrophilicity, both brought by the generation of defective sites induced by the presence of Eu 3+ ions within the ZnO lattice.

Detoxification of corn stalk pretreated with calcium hydroxide for true protein accumulation

Alkaline pretreatment is essential in lignin degradation, but the inhibitors produced in this process affect microbial growth. To overcome the impacts of the phenolic compounds, detoxification was applied to corn stalk pretreated with calcium hydroxide.The results showed that ferulic acid degradation rate can reach 85.11% by laccase at the optimal conditions. Phanerochaete chrysosporium degraded most vanillin (77.19%) and p-hydroxybenzaldehyde (63.82%) but the degradation of ferulic acid (15.34%) was relatively weak. Laccase combined with Phanerochaete chrysosporium detoxified most of the phenolic compounds including 2- methoxy-4-vinylphenol (88.46%) and salicylic acid (58.13%) that hardly decompose alone after calcium hydroxide pretreatment in this study. These results inferred that Phanerochaete chrysosporium might generate some substance during the spore germination and growth period which may cooperate with laccase to decompose the phenolic compounds. After the fermentation of detoxified corn stalk by Neurospora crassa, the true protein content was increased by 2.73 times, and 21.17% lignin was degraded.

Transcriptomic Responses of Rhizobium phaseoli to Root Exudates Reflect Its Capacity to Colonize Maize and Common Bean in an Intercropping System.

Corn and common bean have been cultivated together in Mesoamerica for thousands of years in an intercropping system called “milpa,” where the roots are intermingled, favoring the exchange of their microbiota, including symbionts such as rhizobia. In this work, we studied the genomic expression of Rhizobium phaseoli Ch24-10 (by RNA-seq) after a 2-h treatment in the presence of root exudates of maize and bean grown in monoculture and milpa system under hydroponic conditions. In bean exudates, rhizobial genes for nodulation and degradation of aromatic compounds were induced; while in maize, a response of genes for degradation of mucilage and ferulic acid was observed, as well as those for the transport of sugars, dicarboxylic acids and iron. Ch24-10 transcriptomes in milpa resembled those of beans because they both showed high expression of nodulation genes; some genes that were expressed in corn exudates were also induced by the intercropping system, especially those for the degradation of ferulic acid and pectin. Beans grown in milpa system formed nitrogen-fixing nodules similar to monocultured beans; therefore, the presence of maize did not interfere with Rhizobium–bean symbiosis. Genes for the metabolism of sugars and amino acids, flavonoid and phytoalexin tolerance, and a T3SS were expressed in both monocultures and milpa system, which reveals the adaptive capacity of rhizobia to colonize both legumes and cereals. Transcriptional fusions of the putA gene, which participates in proline metabolism, and of a gene encoding a polygalacturonase were used to validate their participation in plant–microbe interactions. We determined the enzymatic activity of carbonic anhydrase whose gene was also overexpressed in response to root exudates.

Genomic Aromatic Compound Degradation Potential of Novel Paraburkholderia Species: Paraburkholderia domus sp. nov., Paraburkholderia haematera sp. nov. and Paraburkholderia nemoris sp. nov.

We performed a taxonomic and comparative genomics analysis of 67 novel Paraburkholderia isolates from forest soil. Phylogenetic analysis of the recA gene revealed that these isolates formed a coherent lineage within the genus Paraburkholderia that also included Paraburkholderia aspalathi, Paraburkholderia madseniana, Paraburkholderia sediminicola, Paraburkholderia caffeinilytica, Paraburkholderia solitsugae and Paraburkholderia elongata and four unidentified soil isolates from earlier studies. A phylogenomic analysis, along with orthoANIu and digital DNA–DNA hybridization calculations revealed that they represented four different species including three novel species and P. aspalathi. Functional genome annotation of the strains revealed several pathways for aromatic compound degradation and the presence of mono- and dioxygenases involved in the degradation of the lignin-derived compounds ferulic acid and p-coumaric acid. This co-occurrence of multiple Paraburkholderia strains and species with the capacity to degrade aromatic compounds in pristine forest soil is likely caused by the abundant presence of aromatic compounds in decomposing plant litter and may highlight a diversity in micro-habitats or be indicative of synergistic relationships. We propose to classify the isolates representing novel species as Paraburkholderia domus with LMG 31832T (=CECT 30334) as the type strain, Paraburkholderia nemoris with LMG 31836T (=CECT 30335) as the type strain and Paraburkholderia haematera with LMG 31837T (=CECT 30336) as the type strain and provide an emended description of Paraburkholderia sediminicola Lim et al. 2008.

Isolation, identification and characterization of phenolic acid-degrading bacteria from soil.

To isolate, identify and characterize phenolic acid-degrading bacteria and reduce plant growth inhibition caused by phenolic acids. A total of 11 bacterial isolates with high phthalic acid (PA)-degrading ability were obtained using mineral salt medium (MSM) medium containing PA as sole carbon source. These isolates were identified as Arthrobacter globiformis, Pseudomonas putida and Pseudomonas hunanensis by sequence analyses of the 16S rRNA gene. Among them, five Pseudomonas strains could also effectively degrade ferulic acid (FA), p-hydroxybenzoic acid (PHBA) and syringic acid (SA) in MSM solution. P. putida strain 7 and P. hunanensis strain 10 showed highly efficient degradation of PA, SA, FA and PHBA, and could reduce their inhibition of lily, watermelon, poplar and strawberry seedling growth in soils respectively. These two strains could promote plant growth in soil with phenolic acids. In this study, bacterial strains with highly efficient phenolic acid-degrading abilities could not only effectively reduce the autotoxicity of phenolic acids on plants but also were able to promote plant growth in soil with phenolic acids. In this study, Pseudomonas can promote plant growth while degrading phenolic acids. Our results provide new choices for the biological removal of autotoxins.

Degradation of aflatoxin in maize using Ferulic acid (phydroxy-3-methyl cinnamic acid) catalyzed by Hydrogen peroxide

Purpose: The study aimed to determine the rate of degradation of aflatoxin in contaminated maize using ferulic acid catalyzed by hydrogen peroxideMethodology: 100 g of dried maize grain was grounded using a laboratory hammer mill and divided into 2 portions of 50 g each. 20 g sample was taken per portion and treated with 100 mL solution of methanol and deionized water in the ration of 8:1, 50 mL of Acetonitrile, 1 g NaCl and 4 g of anhydrous magnesium sulphate, then blended at 120 RPM for 30 min. Aflatoxin content in each extract was analysed using enzyme-linked immunoassay test kits and confirmed using high performance liquid chromatography (HPLC) coupled with fluorescence detector. Further experiments tested the effect of coating, size, concentration, catalyst and reaction time on degradation of aflatoxin in maize. Data analysis was conducted using SPSS and Microsoft excel.Findings: Four-hour treatment of contaminated maize with 0.5 mM ferulic acid reduced aflatoxin by 91.0% for whole maize, 90.5% for dehulled maize and 90.9% for ground maize. Addition of 20 mL of 0.5% hydrogen peroxide to the reaction mixtures increased degradation of aflatoxin load to 99.0% for whole maize, 99.1% for dehulled maize and 99.1% for ground maize within 4-hour reaction time. The rate of decontamination followed first order kinetics with R2 values of 0.919, 0.916 and 0.930 for the whole maize, dehulled maize, ground maize, respectively and achieved degradation half-lives of 43.59, 41.26 and 39.84 minutes in the same order.Unique contribution to theory, practice and policy: Ferulic acid combined with hydrogen peroxide is an effective degrader of aflatoxin in maize. The rate degradation is dependent on the nature of maize pre-treatment, the concentration of ferulic acid, and the catalyst. Ferulic acid and hydrogen peroxide reacted with the lactone ring of the coumarin moity of aflatoxin. Recommendations; Further studies on degradation of aflatoxin in maize should elucidate the pathways and metabolites formed in the ferulic acid degradation process and determine their toxicities

Transcriptome Profiling Combined With Activities of Antioxidant and Soil Enzymes Reveals an Ability of Pseudomonas sp. CFA to Mitigate p-Hydroxybenzoic and Ferulic Acid Stresses in Cucumber.

Continuous-cropping leads to obstacles in crop productivity by the accumulation of p-hydroxybenzoic acid (PHBA) and ferulic acid (FA). In this study, a strain CFA of Pseudomonas was shown to have a higher PHBA- and FA-degrading ability in media and soil and the mechanisms underlying this were explored. Optimal conditions for PHBA and FA degradation by CFA were 0.2 g/l of PHBA and FA, 37°C, and pH 6.56. Using transcriptome analysis, complete pathways that converted PHBA and FA to acetyl coenzyme A were proposed in CFA. When CFA was provided with PHBA and FA, we observed upregulation of genes in the pathways and detected intermediate metabolites including vanillin, vanillic acid, and protocatechuic acid. Moreover, 4-hydroxybenzoate 3-monooxygenase and vanillate O-demethylase were rate-limiting enzymes by gene overexpression. Knockouts of small non-coding RNA (sRNA) genes, including sRNA 11, sRNA 14, sRNA 20, and sRNA 60, improved the degradation of PHBA and FA. When applied to cucumber-planted soil supplemented with PHBA and FA, CFA decreased PHBA and FA in soil. Furthermore, a reduction of superoxide radical, hydrogen peroxide, and malondialdehyde in cucumber was observed by activating superoxide dismutase, catalase, glutathione peroxidase, ascorbate peroxidase, glutathione reductase, dehydroascorbate reductase, and monodehydroascorbate reductase in seedlings, increasing the reduced glutathione and ascorbate in leaves, and inducing catalase, urease, and phosphatase in the rhizosphere. CFA has potential to mitigate PHBA and FA stresses in cucumber and alleviate continuous-cropping obstacles.

Degradation of Ferulic Acid by the Endophytic Fungus Colletotrichum gloeosporioides TMTM-13 Associated with Ostrya rehderiana Chun.

Biodegradation of ferulic acid, by an endophytic fungus Colletotrichum gloeosporioides TMTM-13 associated with Ostrya rehderiana Chun, was explored in this study. Ferulic acid was completely degraded by TMTM-13 as its initial concentration was lower than 400 mg L–1. Generally, the initial concentration of ferulic acid and fungal biomass of TMTM-13 kept synchronously growing up as the concentration was lower than 400 mg L–1. Fungal biomass reached a maximum of almost 1.177 g L–1 under concentrations of 400–450 mg L–1. HPLC-MS analysis indicated that ferulic acid ultimately degraded to vanillin, vanillic acid, acetovanillone, and dihydroconiferyl alcohol by TMTM-13. This study was the first report about an endophytic fungus associated with O. rehderiana Chun that has great potential for practical application in ferulic acid contaminated environments.

Involvement of a PadR regulator PrhP on virulence of Ralstonia solanacearum by controlling detoxification of phenolic acids and type III secretion system.

Summary Ralstonia solanacearum can metabolize ferulic acid (FA) and salicylic acid (SA), two representative phenolic acids, to protect it from toxicity of phenolic acids. Here, we genetically demonstrated a novel phenolic acid decarboxylase regulator (PadR)‐like regulator PrhP as a positive regulator on detoxification of SA and FA in R. solanacearum. Although the ability to degrade SA and FA enhances the infection process of R. solanacearum toward host plants, PrhP greatly contributes to the infection process besides degradation of SA and FA. Our results from the growth assay, promoter activity assay, RNA‐seq and qRT‐PCR revealed that PrhP plays multiple roles in the virulence of R. solanacearum: (1) positively regulates expression of genes for degradation of SA and FA; (2) positively regulates expression of genes encoding type III secretion system (T3SS) and type III effectors both in vitro and in planta; (3) positively regulates expression of many virulence‐related genes, such as the flagella, type IV pili and cell wall degradation enzymes; and (4) is important for the extensive proliferation in planta. The T3SS is one of the essential pathogenicity determinants in many pathogenic bacteria, and PrhP positively regulates its expression mediated with the key regulator HrpB but through some novel pathway to HrpB in R. solanacearum. This is the first report on PadR regulators to regulate the T3SS and it could improve our understanding of the various biological functions of PadR regulators and the complex regulatory pathway on T3SS in R. solanacearum.

Streptomyces canus GLY-P2 degrades ferulic and p-hydroxybenzoic acids in soil and affects cucumber antioxidant enzyme activity and rhizosphere bacterial community

The present study was conducted to investigate the effectiveness of Streptomyces (GLY-P2) in degradation of ferulic acid (FA) and p-hydroxybenzonic acid (PHBA) in the rhizosphere of cucumbers by assaying the alteration of antioxidant enzymes activities and rhizospheric microbial community. GLY-P2 was isolated, identified as Streptomyces canus, and applied to cucumber-planted soil containing FA and PHBA. Optimal conditions for FA and PHBA degradation by GLY-P2 were 40 °C, pH 7, and 0.2 g l−1 mixture of FA and PHBA. During the degradation, vanillin, vanillic acid, and protocatechoic acid were metabolites; and activities of superoxide dismutase (SOD), catalase, ascorbate peroxidase (APX), and dehydroascorbate reductase in GLY-P2 were induced. When inoculated into cucumber-planted soil containing 220 μg g−1 mixture of FA and PHBA, GLY-P2 degraded FA and PHBA in soil, improved plant growth, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. GLY-P2 also enhanced activities of SOD, catalase, glutathione peroxidase, APX, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, increased contents of ascorbate and glutathione, and elevated transcript levels of copper/zinc SOD, manganese SOD, catalase, and APX in leaves. Moreover, GLY-P2 changed soil bacterial richness, diversity, and community composition, and increased phosphatase, catalase, urease, and sucrase activities in rhizospheric soil. GLY-P2 mitigates FA and PHBA stress in cucumber by activating leaf antioxidant enzymes and affecting soil bacterial community.

Comparative Studies of White-Rot Fungal Strains (Trametes hirsuta MTCC-1171 and Phanerochaete chrysosporium NCIM-1106) for Effective Degradation and Bioconversion of Ferulic Acid.

Biodegradation of ferulic acid, by two white-rot fungal strains (Trametes hirsuta MTCC-1171 and Phanerochaete chrysosporium NCIM-1106) was investigated in this study. Both strains could use ferulic acid as a sole carbon source when provided with basal mineral salt medium. T. hirsuta achieved complete degradation of ferulic acid (350 mg L–1) in 20 h, whereas P. chrysosporium degraded it (250 mg L–1) in 28 h. The metabolites produced during degradation were distinguished by gas chromatography–mass spectrometry. Bioconversion of ferulic acid to vanillin by P. chrysosporium was also investigated. The optimum experimental conditions for bioconversion to vanillin can be summarized as follows: ferulic acid concentration 250 mg L–1, temperature 35 °C, initial pH 5.0, mycelial inoculum 0.32 ± 0.01 g L–1 dry weight, and shaking speed 150 rpm. At optimized conditions, the maximum molar yield obtained was 3.4 ± 0.1%, after 20 h of bioconversion. Considering that the degradation of ferulic acid was determined by laccase and lignin peroxidase to some extent, the possible role of ligninolytic enzymes in overall bioconversion process was also studied. These results illustrate that both strains have the potential of utilizing ferulic acid as a sole carbon source. Moreover, P. chrysosporium can also be explored for its ability to transform ferulic acid into value-added products.

Acinetobacter calcoaceticus CSY-P13 Mitigates Stress of Ferulic and p-Hydroxybenzoic Acids in Cucumber by Affecting Antioxidant Enzyme Activity and Soil Bacterial Community.

Ferulic acid (FA) and p-hydroxybenzoic acid (PHBA) are main phenolic compounds accumulated in rhizosphere of continuously cropped cucumber, causing stress in plants. Microbial degradation of a mixture of FA and PHBA is not well understood in soil. We isolated a strain CSY-P13 of Acinetobacter calcoaceticus, inoculated it into soil to protect cucumber from FA and PHBA stress, and explored a mechanism underlying the protection. CSY-P13 effectively degraded a mixture of FA and PHBA in culture solution under conditions of 39.37°C, pH 6.97, and 21.59 g L-1 potassium dihydrogen phosphate, giving rise to 4-vinyl guaiacol, vanillin, vanillic acid, and protocatechuic acid. During FA and PHBA degradation, activities of superoxide dismutase (SOD), catalase, ascorbate peroxidase, and dehydroascorbate reductase in CSY-P13 were induced. Inoculated into cucumber-planted soil containing 220 μg g-1 mixture of FA and PHBA, CSY-P13 degraded FA and PHBA in soil, increased plant height, and decreased malonaldehyde, superoxide radical, and hydrogen peroxide levels in leaves. CSY-P13 also enhanced SOD, guaiacol peroxidase, catalase, glutathione peroxidase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities; increased ascorbate and glutathione contents; and elevated transcript levels of copper/zinc SOD, manganese SOD, and catalase in leaves under FA and PHBA. Moreover, CSY-P13 increased phosphatase, catalase, urease, and sucrase activities and changed bacterial richness, diversity, and community composition by high throughput sequencing in cucumber-planted soil supplemented with the mixture of FA and PHBA. So CSY-P13 degrades the mixture of FA and PHBA in soil and mitigates stress from the two phenolic compounds in cucumber by activating antioxidant enzymes, changing soil bacterial community, and inducing soil enzymes.

A proteomic analysis of ferulic acid metabolism in Amycolatopsis sp. ATCC 39116.

The pseudonocardiate Amycolatopsis sp. ATCC 39116 is used for the biotechnical production of natural vanillin from ferulic acid. Our laboratory has performed genetic modifications of this strain previously, but there are still many gaps in our knowledge regarding its vanillin tolerance and the general metabolism. We performed cultivations with this bacterium and compared the proteomes of stationary phase cells before ferulic acid feeding with those during ferulic acid feeding. Thereby, we identified 143 differently expressed proteins. Deletion mutants were constructed and characterized to analyze the function of nine corresponding genes. Using these mutants, we identified an active ferulic acid β-oxidation pathway and the enzymes which constitute this pathway. A combined deletion mutant in which the β-oxidation as well as non-β-oxidation pathways of ferulic acid degradation were deleted was unable to grow on ferulic acid as the sole source of carbon and energy. This mutant differs from the single deletion mutants and was unable to grow on ferulic acid. Furthermore, we showed that the non-β-oxidation pathway is involved in caffeic acid degradation; however, its deletion is complemented even in the double deletion mutant. This shows that both pathways can complement each other. The β-oxidation deletion mutant produced significantly reduced amounts of vanillic acid (0.12 instead of 0.35g/l). Therefore, the resulting mutant could be used as an improved production strain. The quinone oxidoreductase deletion mutant (ΔytfG) degraded ferulic acid slower at first but produced comparable amounts of vanillin and significantly less vanillyl alcohol when compared to the parent strain.

Modular Design of Picroside-II Biosynthesis Deciphered through NGS Transcriptomes and Metabolic Intermediates Analysis in Naturally Variant Chemotypes of a Medicinal Herb, Picrorhiza kurroa.

Picroside-II (P-II), an iridoid glycoside, is used as an active ingredient of various commercial herbal formulations available for the treatment of liver ailments. Despite this, the knowledge of P-II biosynthesis remains scarce owing to its negligence in Picrorhiza kurroa shoots which sets constant barrier for function validation experiments. In this study, we utilized natural variation for P-II content in stolon tissues of different P. kurroa accessions and deciphered its metabolic route by integrating metabolomics of intermediates with differential NGS transcriptomes. Upon navigating through high vs. low P-II content accessions (1.3–2.6%), we have established that P-II is biosynthesized via degradation of ferulic acid (FA) to produce vanillic acid (VA) which acts as its immediate biosynthetic precursor. Moreover, the FA treatment in vitro at 150 μM concentration provided further confirmation with 2-fold rise in VA content. Interestingly, the cross-talk between different compartments of P. kurroa, i.e., shoots and stolons, resolved spatial complexity of P-II biosynthesis and consequently speculated the burgeoning necessity to bridge gap between VA and P-II production in P. kurroa shoots. This work thus, offers a forward looking strategy to produce both P-I and P-II in shoot cultures, a step toward providing a sustainable production platform for these medicinal compounds via-à-vis relieving pressure from natural habitat of P. kurroa.

Heterogeneous kinetics, products, and mechanisms of ferulic acid particles in the reaction with NO3 radicals

Methoxyphenols, as an important component of wood burning, are produced by lignin pyrolysis and considered to be the potential tracers for wood smoke emissions. In this work, the heterogeneous reaction between ferulic acid particles and NO3 radicals was investigated. Six products including oxalic acid, 4-vinylguaiacol, vanillin, 5-nitrovanillin, 5-nitroferulic acid, and caffeic acid were confirmed by gas chromatography-mass spectrometry (GC-MS). In addition, the reaction mechanisms were proposed and the main pathways were NO3 electrophilic addition to olefin and the meta-position to the hydroxyl group. The uptake coefficient of NO3 radicals on ferulic acid particles was 0.17 ± 0.02 and the effective rate constant under experimental conditions was (1.71 ± 0.08) × 10−12 cm3 molecule−1 s−1. The results indicate that ferulic acid degradation by NO3 can be an important sink at night.