Production of renewable, high‐value N‐containing chemicals from lignocellulose will expand product diversity and increase the economic competitiveness of the biorefinery. Herein, we report a ...single‐step conversion of furfural to pyrrole in 75 % yield as a key N‐containing building block, achieved via tandem decarbonylation–amination reactions over tailor‐designed Pd@S‐1 and H‐beta zeolite catalytic system. Pyrrole was further transformed into dl‐proline in two steps following carboxylation with CO2 and hydrogenation over Rh/C catalyst. After treating with Escherichia coli, valuable d‐proline was obtained in theoretically maximum yield (50 %) bearing 99 % ee. The report here establishes a route bridging commercial commodity feedstock from biomass with high‐value organonitrogen chemicals through pyrrole as a hub molecule.
Production of renewable nitrogen‐containing chemicals (pyrrole and d‐proline) from biomass‐derived furfural is achieved through a procedure combining chemical and biological processes.
The potential of plant growth regulating microorganisms present in the soil can be explored towards the purpose of identifying salt tolerant strategies and crop cultivars. Current study was designed ...to elucidate the capabilities of salt stress tolerant plant growth promoting rhizobacteria (PGPR) Bacillus siamensis (PM13), Bacillus sp. (PM15) and Bacillus methylotrophicus (PM19) in undermining the effects of salt stress on wheat seedling. Strains were characterized for their IAA (81–113 μM/ml), ACC-deaminase (0.68–0.95 μM/mg protein/h) and exopolysaccharide (EPS) (0.62–0.97 mg/ml) producing activity both under normal and NaCl stressed conditions. Effects of bacterial inoculation on germination and seedling growth of wheat variety Pakistan-13 was observed under induced salinity stress levels (0, 4, 8, 16 dS/m). All the morpho-physiological characteristics of wheat seedlings were affected drastically by the NaCl stress and the growth parameters expressed a negative relationship with increased NaCl levels. PGPR application had a very positive influence on germination rate of wheat seedlings, root and shoot length, photosynthetic pigments etc. Elongated roots and enhanced vegetative shoot growth as well as seedling's fresh and dry weights were highest in plants treated with B. methylotrophicus PM19. Sequestration of Na+ ion by EPS production and degradation of exuded ACC into a-ketobutyrate and ammonia by ACCD bacteria efficiently reduced the impact of salinity stress on wheat growth. Current findings suggested that the used PGPR strains are potential candidates for improving crop growth in salt stressed agricultural systems. However further research validation would be necessary before large scale/field application.
•Bacillus strains showed plant growth promoting traits.•Survival for various range of salinity stress.•All bacillus strains show persistent IAA, ACC deaminase and EPS production.•PGP strains enhance seedling growth, germination percentage and chlorophyll content even under high level of salinity stress.•Resistance to antibiotics revealed its potential to survive and compete native microflora in soil.
Proline is a non‐toxic and inexpensive natural amino acid that is readily available in both enantiomeric forms and was one of the very first compounds to be studied as an organocatalyst. Proline can ...engage in several modes of organocatalysis, as it can behave both as a Brønsted acid or a Brønsted base, and it can also easily generate the iminium or enamine intermediates that are typical of covalent organocatalysis. In view of the importance of diminishing the generation of residues formed by volatile organic solvents, the development of synthetically useful reactions that can be performed in aqueous environments is of increasing significance. The synergic combination of the advantages of water as a reaction medium with the efficiency associated to reactions that are able to generate several bonds in one operation is particularly relevant from the point of view of sustainable chemistry. In this review we critically summarize the use of proline and proline derivatives as catalysts of multi‐component reactions performed in aqueous media and leading to synthetically and biologically relevant heterocycles, a very important class of compounds that constitutes over 60% of drugs and agrochemicals.
•The mitigating effect of Si under saline conditions was studied.•Salinity decreased shoot mass, root volume and essential oil yield.•Salinity led to increased electrolyte leakage and lipid ...peroxidation.•Antioxidant enzyme activity was low under saline conditions.•Weekly Si application improved all assessed parameters.
Salinity stress impedes plant growth and productivity. In this study, the alleviating role of potassium silicate (K2SiO3) under saline conditions was addressed. Geranium plants were grown at three salinity levels (1.8, 4 and 6 ds/m by using NaCl), where K2SiO3 was weekly applied at different concentrations (0, 0.5 or 1 mM). Plant biomass, root volume, leaf pigment (chlorophyll, carotenoids) content and essential oil yield were assessed. Electrolyte leakage, lipid peroxidation, proline content, as well as antioxidant enzyme (catalase and peroxidase) activities were also evaluated. Increasing the salinity level from 1.8 to 4 ds/m, as well as from 4 to 6 ds/m, led to significantly smaller plants, with lower pigment content and reduced essential oil yield. Plants grown under more saline solution also suffered from increased electrolyte leakage and lipid peroxidation. These effects were related to decreased antioxidant enzyme activities. Weekly Si application not only significantly improved all assessed parameters under control conditions (1.8 ds/m), but also partly mitigated the above-mentioned effects under saline conditions (4 and 6 ds/m). This promotive effect of Si was more prominent when applied at 1 mM. Overall, the results show that weekly K2SiO3 application promotes productivity in geranium, in particular under saline stress.
In this study, the effects of different types and concentrations of salts on local Siverek rice plant (Oryza sativa L.) grown in vitro were investigated in terms of mineral elements (K, Ca, P, Mg, ...Na, Fe, Cu, Zn, Mn, Mo, Co), proline, and total protein content. Sterilized seeds were planted in hormone-free and salt-free MS medium. After one week, the seedlings were subjected to different concentrations of NaCl, CaCl2, and MgCl2 salts (0, 30 mM, 90 mM) in order to evaluate the effect of salinity on plant growth and development. In response to salt stress, a decrease in nutrient elements was observed for all three types of salt compared to the control group, which can be attributed to disruptions in ion balance. Changes in element levels generally showed varying levels of increase or decrease depending on both the type and concentration of the salt and these changes were statistically significant. The increase in proline level was found to be directly proportional to the changes in the amounts of Ca, Mg, K, and Na elements. Both total protein and proline content showed the lowest values for all salt concentrations with CaCl2, while the highest values were obtained with NaCl. In conclusion, the changes in the level of mineral elements, total protein, and proline content levels, which decrease or increase in different ratios, depending on the type and concentration rising of the salt, are associated with the varying tolerance of the plant to different types of salts.
In this study, the effects of different types and concentrations of salts on local Siverek rice plant (Oryza sativa L.) grown in vitro were investigated in terms of mineral elements (K, Ca, P, Mg, Na, Fe, Cu, Zn, Mn, Mo, Co), proline, and total protein content. Sterilized seeds were planted in hormone-free and salt-free MS medium. After one week, the seedlings were subjected to different concentrations of NaCl, CaCl2, and MgCl2 salts (0, 30 mM, 90 mM) in order to evaluate the effect of salinity on plant growth and development. In response to salt stress, a decrease in nutrient elements was observed for all three types of salt compared to the control group, which can be attributed to disruptions in ion balance. Changes in element levels generally showed varying levels of increase or decrease depending on both the type and concentration of the salt and these changes were statistically significant. The increase in proline level was found to be directly proportional to the changes in the amounts of Ca, Mg, K, and Na elements. Both total protein and proline content showed the lowest values for all salt concentrations with CaCl2, while the highest values were obtained with NaCl. In conclusion, the changes in the level of mineral elements, total protein, and proline content levels, which decrease or increase in different ratios, depending on the type and concentration rising of the salt, are associated with the varying tolerance of the plant to different types of salts.
Abstract
A novel
C
2
‐symmetrical bisprolinamide organocatalyst was synthesised and used to facilitate asymmetric direct aldol reactions in a water emulsion. Reactions were performed at room ...temperature with very low catalyst loadings (1–2.5 mol%) without the required use of additives, co‐catalysts or extended reaction times (24 h). This catalyst system was then used with a variety of aldehyde substrates showing good reaction generality for benzaldehydes with cyclohexanone (
dr
range 77/23 to >99/1,
anti/syn
;
ee
range 33% to >99%) and moderate scope with cyclopentanone (
dr
range 45/55 to 76/24,
anti/syn
;
ee
range 14% to 68%). Ultra‐low catalysts loadings (0.1 and 0.05 mol%) were also investigated demonstrating catalyst turnover numbers in the order of 1000.
•γ-aminobutyric acid effect on black cumin growth under water stress was studied.•Black cumin showed minimum growth and productivity under severe water stress.•γ-aminobutyric acid at 2.0 mg L−1 ...increased the chlorophyll content in black cumin.•γ-aminobutyric acid increased soluble sugars content, proline, and catalase activity.•γ-aminobutyric acid boosted black cumin growth and productivity under water stress.
Water deficit is an abiotic stress factor that negatively affects black cumin (Nigella sativa L.) production. Gamma aminobutyric acid (GABA), an endogenous signaling molecule and metabolite, has high physiological and molecular activity in plant cells, which can promote tolerance to water deficit stress, but little information is available on the effect of exogenous application on growth of black cumin. A field experiment over two years was carried out at a farm located in Naqadeh-Urmia, West Azerbaijan, Iran to evaluate the effects of GABA on some agronomic and biochemical attributes of black cumin under water deficit stress conditions. Three irrigation treatments (irrigation after 50, 100, and 150 mm evaporation based on evaporation from class A pan) and four levels of GABA application (0, 0.5, 1.0, and 2.0 mg L−1) were tested. Irrespective of GABA application, the severe water deficit treatment (i.e., irrigation after 150 mm evaporation) provided the lowest seed number per follicle, 1000-seed weight, and seed yield. Increasing water deficit, significantly reduced chlorophyll a by 8.2 to 15.8% and chlorophyll b by 18.4 to 41.5%, whereas GABA application significantly improved these traits. The application of 2.0 mg L−1 GABA increased chlorophyll a content by 6.2% and chlorophyll b content by 19.2% compared with control. In addition, GABA application showed a positive and significant effect on soluble sugars content, proline accumulation, and catalase (CAT) activity. The maximum values of these variables were obtained with the application of GABA at 2.0 mg L−1. CAT, peroxidase (POX), and superoxide dismutase (SOD) activity increased with decreasing chlorophyll a and chlorophyll b contents, whereas soluble sugars and proline content increased with increasing activity of those antioxidant enzymes. Overall, in addition to cellular mechanisms, such as osmoregulation and antioxidant defense, GABA application can improve growth and productivity of black cumin under water deficit stress conditions.
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•Catalytic pyrolysis of leucine and proline were carried out in a micro-furnace pyrolyzer.•Distributions of carbon, oxygen and nitrogen were comparatively investigated.•Leucine ...yielded 29.6% aromatic hydrocarbons, 34.9% olefins, and 8.1% alkanes.•Proline yielded 25.3% aromatic hydrocarbons, 14.0% olefins, and 5.5% alkanes.•Insights into the deoxygenation pathways of leucine and proline were elucidated.
Catalytic pyrolysis (CP) of protein-rich biomass such as microalgae is a promising approach to biofuel production. CP of amino acids can help understand the cracking of protein-rich biomass in the presence of zeolite catalysts. In this study, as representatives of aliphatic amino acid and cyclic amino acid, respectively, leucine and proline were pyrolyzed with ZSM-5 catalyst in a Tandem micro-furnace reactor coupled with a MS/FID/TCD. At 650°C, leucine produced more hydrocarbons (aromatic hydrocarbons of 29.6%, olefins of 34.9% and alkanes of 8.1%) than proline (aromatic hydrocarbons of 25.3%, olefins of 14.0% and alkanes of 5.5%) because its relatively simpler amino structure readily detached as ammonia during CP. However, with an N-cyclic structure, proline produced large quantities of nitrogen-containing heterocyclic compounds that favored coke formation in CP. Accordingly, 28.2% of the nitrogen in proline was retained in the solid residue while most of the nitrogen in leucine was converted into ammonia leaving only 4.3% in the solid residue. In addition, though decarboxylation to carbon dioxide was favored in non-catalytic pyrolysis of leucine and proline, decarbonylation to carbon monoxide became the primary deoxygenation pathway in CP. These results indicate that the chemical structures of amino acids have significant effects on product distributions during CP and N-cyclic amino acid is less favored in CP for production of hydrocarbons and ammonia.
•Drought induces osmoregulation in fennel.•Exogenous proline enhances osmoregulation.•Genotypic variation exists in fennel’s response to proline.•Drought and exogenous proline increase fennel’s ...essential oil concentration.
Proline is an amino acid with pivotal role in plant responses to environmental constraints. Effects of its foliar application (20mM) on physiological functions of 12 fennel (Foeniculum vulgare Mill.) genotypes at the presence of different moisture conditions (non-stress control and drought stress) was studied in a 2-year field study. Drought led to notable increases in mean leaf polyphenol, proline and total soluble carbohydrates and essential oil concentrations, despite decreases in carotenoids and chlorophyll concentrations, leaf water potential, relative water content, plant above-ground dry mass and water use efficiency. Exogenous proline resulted in significant increases in mean carotenoids, polyphenol, chlorophyll, proline, total soluble carbohydrates and essential oil concentrations and relative water content, but it caused a decrease in leaf water potential. Proline amendment positively affected plant water relations, due mostly to enhancement in osmoregulation, as certain genotypes with greater mean leaf proline concentration and relative water content appeared to produce greater above-ground dry mass, when exposed to the external proline. Ameliorative effects of exogenous proline tended to be greater in drought-stressed plants, as it led to the enhancement of chlorophyll concentration and relative water content of fennel in drought conditions. Genotypes Urmia and Yazd were found to be able to withstand better against drought and benefit more from external proline. Our findings suggest that while indigenous proline is the most sensitive osmoticum in fennel’s response to drought, its external amendment may bring about improvements in water relations and osmoregulatory measure in this medicinal plant.
![[delta]15N from soil to win...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1076-5174/small "[delta]15N from soil to wine in bulk samples and proline")
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