scholarly journals Kinetic modeling of anaerobic degradation of plant-derived aromatic mixtures by Rhodopseudomonas palustris

2021 ◽  
Vol 32 (2) ◽  
pp. 179-192
Author(s):  
Yanjun Ma ◽  
Timothy J. Donohue ◽  
Daniel R. Noguera

AbstractRhodopseudomonas palustris is a model microorganism for studying the anaerobic metabolism of aromatic compounds. While it is well documented which aromatics can serve as sole organic carbon sources, co-metabolism of other aromatics is poorly understood. This study used kinetic modeling to analyze the simultaneous degradation of aromatic compounds present in corn stover hydrolysates and model the co-metabolism of aromatics not known to support growth of R. palustris as sole organic substrates. The simulation predicted that p-coumaroyl amide and feruloyl amide were hydrolyzed to p-coumaric acid and ferulic acid, respectively, and further transformed via p-coumaroyl-CoA and feruloyl-CoA. The modeling also suggested that metabolism of p-hydroxyphenyl aromatics was slowed by substrate inhibition, whereas the transformation of guaiacyl aromatics was inhibited by their p-hydroxyphenyl counterparts. It also predicted that substrate channeling may occur during degradation of p-coumaroyl-CoA and feruloyl-CoA, resulting in no detectable accumulation of p-hydroxybenzaldehyde and vanillin, during the transformation of these CoA ligated compounds to p-hydroxybenzoic acid and vanillic acid, respectively. While the simulation correctly represented the known transformation of p-hydroxybenzoic acid via the benzoyl-CoA pathway, it also suggested co-metabolism of vanillic acid and syringic acid, which are known not to serve as photoheterotrophic growth substrate for R. palustris.

2019 ◽  
Author(s):  
J. Zachary Oshlag ◽  
Yanjun Ma ◽  
Kaitlin Morse ◽  
Brian T. Burger ◽  
Rachelle A. Lemke ◽  
...  

ABSTRACTWhile lignin represents a major fraction of the carbon in plant biomass, biological strategies to convert the components of this heterogenous polymer into products of industrial and biotechnological value are lacking. Syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) is a byproduct of lignin degradation, appearing in lignocellulosic hydrolysates, deconstructed lignin streams, and other agricultural products. Rhodopseudomonas palustris CGA009 is a known degrader of phenolic compounds under photoheterotrophic conditions, via the benzoyl-CoA degradation (BAD) pathway. However, R. palustris CGA009 is reported to be unable to metabolize meta-methoxylated phenolics such as syringic acid. We isolated a strain of R. palustris (strain SA008.1.07), adapted from CGA009, which can grow on syringic acid under photoheterotrophic conditions, utilizing it as a sole source of organic carbon and reducing power. An SA008.1.07 mutant with an inactive benzoyl-CoA reductase structural gene was able to grow on syringic acid, demonstrating that the metabolism of this aromatic compound is not through the BAD pathway. Comparative gene expression analyses of SA008.1.07 implicated the involvement of products of the vanARB operon (rpa3619-rpa3621), which has been described as catalyzing aerobic aromatic ring demethylation in other bacteria, in anaerobic syringic acid degradation. In addition, experiments with a vanARB deletion mutant demonstrated the involvement of the vanARB operon in anaerobic syringic acid degradation. These observations provide new insights into the anaerobic degradation of meta-methoxylated and other aromatics by R. palustris.IMPORTANCELignin is the most abundant aromatic polymer on Earth and a resource that could eventually substitute for fossil fuels as a source of aromatic compounds for industrial and biotechnological applications. Engineering microorganisms for production of aromatic-based biochemicals requires detailed knowledge of metabolic pathways for the degradation of aromatics that are present in lignin. Our isolation and analysis of a Rhodopseudomonas palustris strain capable of syringic acid degradation reveals a previously unknown metabolic route for aromatic degradation in R. palustris. This study highlights several key features of this pathway and sets the stage for a more complete understanding of the microbial metabolic repertoire to metabolize aromatic compounds from lignin and other renewable sources.


2015 ◽  
Vol 11 (3) ◽  
pp. 3352-3356
Author(s):  
Cheng-Ta Li Chen ◽  
Chiu-Li Kao ◽  
Chi-Ming Liu ◽  
Wei-Jen Li ◽  
Hsing-Tan Li ◽  
...  

Twelve compounds, including three flavonoids, 5-hydroxy-4¢,7- dimethoxyflavone (1) [22], luteolin-7,3¢,4¢-trimethyl ether (2) and 5,3¢- dihydroxy-7,4¢-dimethoxyflavone (3), five benzenoids, methylparaben (4), vanillic acid (5), p-hydroxybenzoic acid (6), syringic acid (7), and isovanillic acid (8) and four steroids, b-sitosterol (9), stigmasterol (10), b-sitostenone (11) and stigmasta-4,22-dien-3- one (12) were isolated from the leaves of Aquilaria agallocha (Thymelaeaceae). All of these compounds (1-12) were obtained for the first time from the leaves of this plant.


2019 ◽  
Vol 86 (3) ◽  
Author(s):  
J. Zachary Oshlag ◽  
Yanjun Ma ◽  
Kaitlin Morse ◽  
Brian T. Burger ◽  
Rachelle A. Lemke ◽  
...  

ABSTRACT While lignin represents a major fraction of the carbon in plant biomass, biological strategies to convert the components of this heterogeneous polymer into products of industrial and biotechnological value are lacking. Syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) is a by-product of lignin degradation, appearing in lignocellulosic hydrolysates, deconstructed lignin streams, and other agricultural products. Rhodopseudomonas palustris CGA009 is a known degrader of phenolic compounds under photoheterotrophic conditions via the benzoyl coenzyme A (CoA) degradation (BAD) pathway. However, R. palustris CGA009 is reported to be unable to metabolize meta-methoxylated phenolics, such as syringic acid. We isolated a strain of R. palustris (strain SA008.1.07), adapted from CGA009, which can grow on syringic acid under photoheterotrophic conditions, utilizing it as a sole source of organic carbon and reducing power. An SA008.1.07 mutant with an inactive benzoyl-CoA reductase structural gene was able to grow on syringic acid, demonstrating that the metabolism of this aromatic compound is not through the BAD pathway. Comparative gene expression analyses of SA008.1.07 implicated the involvement of products of the vanARB operon (rpa3619, rpa3620, rpa3621), which has been described as catalyzing aerobic aromatic ring demethylation in other bacteria, in anaerobic syringic acid degradation. In addition, experiments with a vanARB deletion mutant demonstrated the involvement of the vanARB operon in anaerobic syringic acid degradation. These observations provide new insights into the anaerobic degradation of meta-methoxylated and other aromatics by R. palustris. IMPORTANCE Lignin is the most abundant aromatic polymer on Earth and a resource that could eventually substitute for fossil fuels as a source of aromatic compounds for industrial and biotechnological applications. Engineering microorganisms for the production of aromatic-based biochemicals requires detailed knowledge of the metabolic pathways for the degradation of aromatics that are present in lignin. Our isolation and analysis of a Rhodopseudomonas palustris strain capable of syringic acid degradation reveal a previously unknown metabolic route for aromatic degradation in R. palustris. This study highlights several key features of this pathway and sets the stage for a more complete understanding of the microbial metabolic repertoire required to metabolize aromatic compounds from lignin and other renewable sources.


1981 ◽  
Vol 27 (6) ◽  
pp. 636-638 ◽  
Author(s):  
Anthony L. Pometto III ◽  
John B. Sutherland ◽  
Don L. Crawford

Streptomyces setonii (strain 75Vi2) was grown at 45 °C in liquid media containing simple aromatic compounds as principal carbon sources. Thin-layer chromatography, UV spectrophotometry, and gas chromatography were used to show that S. setonii converted benzoic acid, guaiacol, and vanillic acid to catechol; p-hydroxybenzoic acid to protocatechuic acid; and m-hydroxybenzoic acid to gentisic acid. Presence of the ring-cleavage enzymes catechol 1,2-dioxygenase, protocatechuate 3,4-dioxygenase, and gentisate 1,2-dioxygenase was shown both by O2 uptake in ring-cleavage reactions catalyzed by cell-free extracts and by changes in UV spectra that indicated the presence of specific ring-cleavage products. A unique feature of this strain was its catabolism of vanillic acid by way of guaiacol and catechol, using a pathway that had not been confirmed previously.


Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1260
Author(s):  
Stefanie Duvigneau ◽  
Robert Dürr ◽  
Jessica Behrens ◽  
Achim Kienle

Biopolymers are a promising alternative to petroleum-based plastic raw materials. They are bio-based, non-toxic and degradable under environmental conditions. In addition to the homopolymer poly(3-hydroxybutyrate) (PHB), there are a number of co-polymers that have a broad range of applications and are easier to process in comparison to PHB. The most prominent representative from this group of bio-copolymers is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). In this article, we show a new kinetic model that describes the PHBV production from fructose and propionic acid in Cupriavidus necator (C. necator). The developed model is used to analyze the effects of process parameter variations such as the CO2 amount in the exhaust gas and the feed rate. The presented model is a valuable tool to improve the microbial PHBV production process. Due to the coupling of CO2 online measurements in the exhaust gas to the biomass production, the model has the potential to predict the composition and the current yield of PHBV in the ongoing process.


Author(s):  
Jakub Drewnowski ◽  
Jacek Makinia ◽  
Lukasz Kopec ◽  
Francisco-Jesus Fernandez-Morales

The biodegradation of particulate substrates starts by a hydrolytic stage. Hydrolysis is a slow reaction and usually becomes the rate limiting step of the organic substrates biodegradation. The objective of this work was to evaluate a novel hydrolysis concept based on a modification of the activated sludge model (ASM2d) and to compare it with the original ASM2d model. The hydrolysis concept was developed in order to accurately predict the use of internal carbon sources in enhanced biological nutrient removal (BNR) processes at a full scale facility located in northern Poland. Both hydrolysis concepts were compared based on the accuracy of their predictions for the main processes taking place at a full-scale facility. From the comparison, it was observed that the modified ASM2d model presented similar predictions to those of the original ASM2d model on the behavior of chemical oxygen demand (COD), NH4-N, NO3-N, and PO4-P. However, the modified model proposed in this work yield better predictions of the oxygen uptake rate (OUR) (up to 5.6 and 5.7%) as well as in the phosphate release and uptake rates.


1964 ◽  
Vol 19 (9) ◽  
pp. 781-783 ◽  
Author(s):  
Hans Grisebach ◽  
Karl-Otto Vollmer

Further investigations on the biosynthesis of benzoic acids in Gaultheria procumbens L. have shown that besides salicylic acid all the other benzoic acids (gentisinic acid, p-hydroxybenzoic acid, protocatechuic acid, o-pyrocatechuic acid(?), syringic acid and vanillinic acid) can be formed from cinnamic acid. In the case of vanillinic acid it was proved that the total activity is located in the carboxyl group when cinnamic acid-[3-14C] is the precursor.Formiat-14C is incorporated into the methylester group of methylsalicylate.


2019 ◽  
Vol 14 (8) ◽  
pp. 1934578X1986887
Author(s):  
Zhana Petkova ◽  
Galina Stefanova ◽  
Tania Girova ◽  
Ginka Antova ◽  
Magdalena Stoyanova ◽  
...  

Bay laurel ( Laurus nobilis L.) is an evergreen tree. The objective of this study was to determine the chemical composition (polyphenols, essential oil [EO], lipid fraction, cellulose, and protein content) of laurel fruits collected from Greece (Mount Athos) and Georgia (the village of Meria), and to evaluate the antimicrobial activity of laurel fruit EOs. The major phenolic acids in the fruits from Greece were p-coumaric acid (free 261.6 µg/g) and vanillic acid (free 253.1 µg/g and conjugated 925.8 µg/g). The major phenolic acids in fruits from Georgia were vanillic acid (free 105.6 µg/g and caffeic acid [conjugated 439.2 µg/g], and syringic acid [conjugated 390.7 µg/g]). The laurel fruit EOs from Greece (1.4% content) and Georgia (1.6%) had distinct composition. Monoterpene hydrocarbons were the dominant group of compounds in the EOs, with 49.7% in the EO from Greece and 68.7% in the EO from Georgia. The major constituents of the fruit EO from Greece were 1,8-cineole (18.2%), α-phellandrene (15.0 %), β-pinene (9.4%), and α -pinene (9.1%), whereas the ones from Georgia were trans-β-ocimene (59.4%) and 1,8-cineole (7.6%). Laurel fruit EO from Greece and Georgia demonstrated low to moderate antimicrobial activity against pathogenic and spoilage microorganisms and the dimorphic yeast Candida albicans. The main fatty acids (FAs) in the lipid fractions were oleic, palmitic, and linoleic; there were differences in FA composition between the shells and the seeds of the fruits from the two countries. γ-Тocopherol predominated in the tocopherol fraction of the lipids from fruits shells and seeds from Greece (65.3% and 54.4%, respectively), whereas β-tocopherol predominated in fruits shells and seeds from Georgia (93.7% and 45.6%, respectively). Currently underutilized, the laurel fruits from both Greece and Georgia contain various valuable compounds that may potentially be used for perfumery, cosmetic, and pharmaceutical applications.


2012 ◽  
Author(s):  
Mohd. Sahaid Hj. Kalil ◽  
Muhammad Zaki ◽  
Wan Mohtar Wan Yusoff ◽  
Mohammad Ramlan Mohd. Salleh

Penyelidikan ini bertujuan untuk menyaring substrat organik bagi untuk penghasilan sel–sel A. woodii teraruh demetilase. Pertumbuhan A. woodii dilakukan dalam medium “Balch” yang mengandungi sumber karbon berbeza dalam keadaan anaerobik. Sebanyak sebelas substrat telah diuji iaitu anisol, 2– dan 3–metoksifenol, asid vanilik, asid siringik, asid 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzoik, 2,3,4–, 2,4,5– dan 3,4,5–trimetoksi benzil alkohol. 2–metoksifenol merupakan substrat terbaik untuk pertumbuhan A. woodii pada kadar pertumbuhan spesifik 0.14 j–1. Penghasilan sel–sel teraruh demetilase dilakukan dalam kultur kemostat pada kadar pencairan (D) 0.0j–1. Sel-sel pada keadaan mantap dituai dalam keadaan anaerobik dan dipekatkan sebelum digunakan. Pertumbuhan A. woodii didapati maksimum dengan menggunakan kepekatan 0.62 g/L 2–metoksifenol sebagai sumber karbon tunggal. Tindak balas penyahmetilan oleh sel–sel A. woodii meningkat sebanyak 78% apabila 2–metoksifenol sebanyak 0.31 g/L ditambah dalam medium yang mengandungi fruktosa (1% w/v) semasa kultur kemostat. Kata kunci: tindak balas penyahmetilan; demetilase; sel-sel tertuai; metosiaromatik, Acetobacteriumwoodii The objective of this project was to screen organic substrate suitable for the growth of A. woodii, and as for the production of demethylase. A. woodii was grown in “Balch” medium containing different carbon sources. Eleven substrates were tested including anisole, 2– and 3–methoxyphenol, vanilic acid, syringic acid, 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzoic acid and 2,3,4–, 2,4,5– and 3,4,5–trimethoxy benzyl alcohol. It was found that 2–methoxyphenol was the best substrate with a specific growth rate of 0.14 h–1. The production of demethylase induced cells was carried out in a chemostat culture at a dilution rate (D) of 0.08 h–1. Cells were harvested at steady state of growth and concentrated before use. Optimal concentration of 2–methoxvphenol as the sole carbon source was 0.62 g/L. Demethylation reaction of 0.31 g/L 2–methoxyphenol by induced culture increases 78% relative to the chemostat culture containing only fructose. Key words: Demethylation reaction; demethylase; harvested cells; methoxyaromatic; Acetobacteriumwoodii


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