1,318 research outputs found
Novel fertilising products from lignin and its derivatives to enhance plant development and increase the sustainability of crop production
No full textLignin is a by-product of biorefineries and paper mills and is usually discarded or burnt. However, it may represent a source of novel fertilising products, able to support the sustainable intensification of agricultural productions. The aim of this review is to explore the literature regarding the effect of lignin application towards plant growth and nutrient use efficiency. First, we reviewed the biostimulant role of lignin, which was reported to positively perturbing plant hormonal balances or improving the efficiency of photosynthesis and respiration. Also, when added to soils, lignin was shown to enhance nitrogen uptake, as well as the development of beneficial soil microorganisms. Then, we summarised the research related to the chemical modifications of lignin structure devised to boost its bioactivity, an approach opening possibilities to tailor the effects of lignin addition on plant development. We further examined the literature about the use of lignin and its derivatives as starting substrates to produce sustainable materials (chelates, coatings, micro- and nano-materials) for the slow release of plant nutrients. Encouraging results emerged from the summarised articles, suggesting that lignin may replace the currently used synthetic polymers exploited to chelate or entrapping nutrients. We additionally hereby highlighted the role of lignin chemical nature in affecting its biological and release properties, hence pointing out the relevance of thoroughly studying its structure at a molecular level by the most advanced analytical tools. Finally, we suggested the need for researchers to combine their skills and expertise, in order to develop more efficient lignin-inspired fertilisers
Reduced complexity of multidimensional and diffusion NMR spectra of soil humic fractions as simplified by Humeomics
No full textBackground: Humeomics is a sequential step-wise chemical fractionation that simplifies the complex matrix of a humic acid (HA) and weakens its supramolecular interactions, thereby allowing a detailed characterization of the involved molecules. A recalcitrant residual end product of Humeomics, namely RES4, was successfully solubilized here in alkaline conditions and subjected to a semi-preparative high-performance size exclusion chromatography (HPSEC). Results: The resulting six size fractions separated by HPSEC were analyzed by different NMR techniques. 1D 1H-NMR spectra did not reveal significant molecular differences among size fractions, although all of them differed from the spectrum of the bulk RES4 especially in signal intensity for aliphatic materials, which were assigned by 2D NMR to lipidic structures. Diffusion-ordered spectroscopy (DOSY)-NMR spectra showed that the homogeneity of RES4 was significantly changed by the HPSEC separation. In fact, nominally large size fractions, rich in lipidic signals, had significantly lower and almost constant diffusivity, due to stable supramolecular associations promoted by hydrophobic interactions among alkyl chains. Conversely, diffusivity is gradually increased with the content of aromatic and hydroxyaliphatic signals, which accompanied the reduction of fractions sizes and was related to smaller superstructures. Conclusions: This study not only confirmed the occurrence of supramolecular structures in the recalcitrant humic residue of Humeomics, but also highlighted that more homogeneous size fractions were more easily characterized by NMR spectroscopy
The Soil Humeome: Chemical Structure, Functions and Technological Perspectives
No full textHumus or humic substances (HS) are of pivotal importance in the global
ecosystem dynamics, since fluctuation in their amount affects not only the growth of
both plants and soil microorganisms, but also the main biogeochemical cycles. The
development of technologies aimed at controlling HS in the agroecosystem processes
is hindered by the limited knowledge of their chemical structure and dynamics. The
recent acknowledgement of the supramolecular nature of soil HS allowed to devise
a fractionation procedure, called Humeomics, that enables a detailed characterization of the structure of humic molecules in soil. Humeomics produces homogeneous
fractions by progressively breaking esters and ether C–O bonds but not carbon—
carbon bonds. The molecules in fractions are then identified by means of advanced
spectroscopic and mass spectrometric techniques, thereby providing a body of structures that may well represent the soil Humeome. Humeomics enabled to unravel the
effects of different soil management practices on soil carbon dynamics and to explain
the recalcitrance of HS in soil. Moreover, the application of Humeomics allowed to
corroborate the novel concept of humification, that is unambiguously described as
the progressive accumulation of hydrophobic molecular components, which are no
longer biotically accessible, due to their rapid thermodynamically driven partitioning
from liquid to the solid soil phases. Conceiving HS as supramolecular associations of
relatively small compounds also helped to unravel the reactivity of HS with respect
to plant and microbial development, as well as towards xenobiotics. Finally, the
supramolecular understanding of HS encouraged the proposal of an innovative technology for the control of organic matter stabilization in soil. This is based on the in situ
photo-polymerization of humic molecules catalysed by metal porphyrin biomimetic catalysts. The resulting increase in the molecular mass of humic molecules was found
not only to increase soil aggregate stability but also to sequester in soil significant
yearly amounts of organic carbon. It is expected that the research findings presented
here will prompt novel studies on the man-driven control of t he soil Humeome in
order to increase its content in soil, and contribute to positively affect both crop yields
and soil microbial activity
Water-Soluble Lignins from Different Bioenergy Crops Stimulate the Early Development of Maize (Zea mays, L.)
No full textThe molecular composition of water-soluble lignins isolated from four non-food bioenergy crops (cardoon CAR, eucalyptus EUC, and two black poplars RIP and LIM) was characterized in detail, and their potential bioactivity towards maize germination and early growth evaluated. Lignins were found to not affect seed germination rates, but stimulated the maize seedling development, though to a different extent. RIP promoted root elongation, while CAR only stimulated the length of lateral seminal roots and coleoptile, and LIM improved only the coleoptile development. The most significant bioactivity of CAR was related to its large content of aliphatic OH groups, C-O carbons and lowest hydrophobicity, as assessed by (31)P-NMR and (13)C-CPMAS-NMR spectroscopies. Less bioactive RIP and LIM lignins were similar in composition, but their stimulation of maize seedling was different. This was accounted to their diverse content of aliphatic OH groups and S- and G-type molecules. The poorest bioactivity of the EUC lignin was attributed to its smallest content of aliphatic OH groups and largest hydrophobicity. Both these features may be conducive of a EUC conformational structure tight enough to prevent its alteration by organic acids exuded from vegetal tissues. Conversely the more labile conformational arrangements of the other more hydrophilic lignin extracts promoted their bioactivity by releasing biologically active molecules upon the action of exuded organic acids. Our findings indicate that water-soluble lignins from non-food crops may be effectively used as plant biostimulants, thus contributing to increase the economic and ecological liability of bio-based industries
Humic-Like Water-Soluble Lignins from Giant Reed (Arundo donax L.) Display Hormone-Like Activity on Plant Growth
No full textLignin nanoparticles from hydrotropic fractionation of giant reed and eucalypt: Structural elucidation and antibacterial properties
No full text: A hydrotropic solution of maleic acid (MA) was exploited to fractionate giant reed (AD) and eucalypt (EUC). The pre-treatment was successful for AD, while it was unsatisfactory for EUC, likely due to unoptimized reaction conditions. Interestingly, lignin nanoparticles (LNP) were produced via spontaneous aggregation following spent liquor dilution. LNP were studied by a plethora of analytical techniques, such as thermogravimetry, electron microscopy, and Nuclear Magnetic Resonance spectroscopy (NMR). Notwithstanding LNP from both AD and EUC showed similar thermal behaviour and morphology, a greater content of aliphatic hydroxyl, carboxyl, guaiacyl and p-hydroxyphenyl moieties was reported for AD-LNP, whereas EUC-LNP had a larger amount of syringyl groups and a higher S/G ratio. Also, the 1H-DOSY NMR indicated the lower size of AD-LNP. Moreover, the LNP were found to negatively impact on the development of several human or plant pathogens, and their bioactivity was related to the occurrence of guaiacyl and p-hydroxyphenyl moieties and a lower the LNP size. We therefore found that MA delignification allows both to achieve high delignification efficiency and to obtain LNP with promising antibacterial effect. Such LNP may help counteracting the antibiotics resistance and sustain the quest for finding sustainable agrochemicals
Molecular composition of water-soluble lignins separated from different non-food biomasses
No full textSeparation of water-soluble lignins from lignocellulosic biomass provides a new and still poorly exploited feedstock to increase the sustainability of biorefineries. We applied derivatization followed by a reductive cleavage (DFRC) method, 2D-HSQC-NMR, and 31PNMR after 31P-labeling, to investigate molecular composition in water-soluble lignins obtained by alkaline oxidation from three biomass materials for energy (miscanthus, giant reed and an industrially pre-treated giant reed). Chromatographic identification of lignin products cleaved by DFRC showed a large predominance of guaiacyl (G) units in all biomasses and a lesser abundance of syringyl (S) and p-coumaryl (P) monomers. Our S/G ratios disagree with those reported in literature by other lignin separation methods. Carboxyl functions (ferulic and pcoumaric acids) were revealed by heterocorrelated 1H-13C HSQC-NMR, and confirmed by 31P-NMR spectra of 31 P-labeled lignin molecules. An understanding of molecular composition of water-soluble lignins from biomass sources for energy is essential for lignin most efficient exploitation in either industrial or agricultural applications
Biorefinery Process Combining Specel® Process and Selective Lignin Precipitation using Mineral Acids
No full textSoda black liquors from the Specel® process, which used wheat straw as the raw material, were subjected to an acid precipitation process to recover the lignin. Lignin was isolated by acid precipitation using three different inorganics acids (H3PO4, H2SO4, and HCl) at three concentration levels, and at pH values of 2 and 4. Even though the highest lignin yield was achieved using phosphoric acid, the most economical inorganic acid was sulphuric acid. Physico-chemical characterizations of the precipitated lignin samples were performed using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) (for thermal properties), Fourier transform infrared spectroscopy (FT-IR), and heteronuclear single quantum correlation spectroscopy (HSQC) (for chemical structures). No significant differences were found in the thermal properties and chemical structures of the isolated lignins, except for the lignin obtained with phosphoric acid to lower the black liquor from pH 10.72 to pH 2. Apart from the lignin fraction collected, the soda pulp obtained by the Specel® process using wheat straw could represent a good alternative for packaging industries
Correction to: When terminology hinders research: the colloquialisms of transitions of control in automated driving (Cognition, Technology & Work, (2022), 10.1007/s10111-022-00705-3)
No full textIn the original article, author affiliation published with error. The correct affiliations are: Davide Maggi—Institute for Transport Studies, Leeds, UK. Richard Romano—Institute for Transport Studies, Leeds, UK. Oliver Carsten—Institute for Transport Studies, Leeds, UK. Joost C. F. De Winter—Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands. The original article has been corrected.Human-Robot Interactio
- …
