Isolation of humic acid from the terrestrial plant Brugmansia sanguinea

Davies, Geoffrey; Fataftah, Amjad; Radwan, Amal; Raffauf, Robert F.; Ghabbour, Elham A.; Jansen, Susan A.

doi:10.1016/s0048-9697(97)84054-5

Cited by 16 publications

(5 citation statements)

References 4 publications

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“…In 1989 [9] and 1991 [2], we reported for the first time that humic acids are present in senescent plant and algal matter, which meant that they enter the soil prior to any supposed conversion of plant lignins by microbes. Similar results have been reported since then [10,11]. More recently [12], humic acids were isolated from maize plants at different stages of maturity, and it was concluded that humic acids originate from the preservation of plant tissue.…”

Section: Introductionsupporting

confidence: 83%

Replenishing Humic Acids in Agricultural Soils

Susic

2016

Agronomy

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For many decades, it was commonly believed that humic acids were formed in soils by the microbial conversion of plant lignins. However, an experiment to test whether these humic acids were formed prior to plant matter reaching the soil was never reported until the late 1980s (and then only as a side issue), even though humic acids were first isolated and reported in 1786. This was a serious omission, and led to a poor understanding of how the humic acid content of soils could be maintained or increased for optimum fertility. In this study, commercial sugar cane mulch and kelp extracts were extracted with alkali and analyzed for humic acid content. Humic acids in the extracts were positively identified by fluorescence spectrophotometry, and this demonstrated that humic acids are formed in senescent plant and algal matter before they reach the soil, where they are then strongly bound to the soil and are also resistant to microbial metabolism. Humic acids are removed from soils by wind and water erosion, and by water leaching, which means that they must be regularly replenished. This study shows that soils can be replenished or fortified with humic acids simply by recycling plant and algal matter, or by adding outside sources of decomposed plant or algal matter such as composts, mulch, peat, and lignite coals.

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Section: Introductionsupporting

confidence: 83%

Replenishing Humic Acids in Agricultural Soils

Susic

2016

Agronomy

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“…The strong peaks at 3700-3200 cm 21 in all spectra could be attributed to the presence of O-H or N-H stretching. The strong bands at the range of 1630-1620 cm 21 could be assigned to the C5O stretch (amide), aromatic C5C, hydrogen-bonded C5O, or COO 2 asymmetrical stretch [28][29][30]. Compared with the fractions A and B, the fractions C and D show relatively more intense bands at 1630-1620 cm 21 .…”

Section: Ftir Spectroscopymentioning

confidence: 96%

Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

Quan

et al. 2008

Front. Environ. Sci. Eng. China

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Four fractions (A, B, C, and D) of humic acids (HAs) were separated based on the polarity from weak to strong. UV-vis absorption and Fourier transform infrared spectroscopy (FTIR) analysis show that the fractions C and D possessed more aromatic C5C content. The influences of HAs and their fractions on the photolysis were investigated by the photodegradation of 2,4-D solutions under simulated solar light irradiation. The degradation rate of 2,4-D was found to decrease in the presence of bulk HAs or their fractions especially at high HAs concentration. The fractions of strong polarity C and D retarded the degradation rate more than the fractions of weak polarity A and B. This could be attributed to the different absorption intensity of the four HAs fractions in the order of D > C . A . B, and the stronger p-p electron donor-acceptor interactions between the strong polar fractions and 2,4-D.

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“…Hence there is an urgent need for inert, bioacceptable materials capable of withstanding the strong oxidative environment in vivo. Humic acids (HAs) are biopolymers found in soil, sediments, water, and some plants such as tobacco. − Although their origin is ambiguous, it is speculated that they may have evolved from the auto-oxidation and condensation of lignin and polyphenols during the humification process or are produced during in vivo biosynthesis in plants . Humic acids are deemed as the final product of the biodegradative and oxidative route, with a mean residence time up to 1200 years in soil, and probably will not undergo any further breakdown unless they are exposed to agents they have not previously encountered .…”

Section: Introductionmentioning

confidence: 99%

Characterization and Biocompatibility Studies of Novel Humic Acids Based Films as Membrane Material for an Implantable Glucose Sensor

et al. 2001

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Multilayered films of humic acids (HAs) (naturally occurring biopolymers) were investigated as a potential semipermeable membrane for implantable glucose sensors. These films were grown using a layer-by-layer self-assembly process of HAs and oppositely charged ferric ions. The growth of these assemblies exhibited strong dependence on the pH and ionic strength of HAs solutions, which correlated with the degree of ionization of the carboxyl groups and neutralization-induced surface spreading. Quartz crystal microbalance (QCM) and ellipsometric studies have shown repeatable, stepwise increase in mass (as high as 5.63 microg/cm(2)) and in film thickness (ca. 24.3 nm per layer) for these assemblies. The permeability of glucose through these membranes can be regulated by varying the number of self-assembled HAs/Fe(3+) layers. Moreover, a 200 nm thick HAs/Fe(3+) film (in its hydrated state) had a shear modulus of about 80 MPa, implying stability upon implantation. These films were determined to be biocompatible since in vivo studies indicated only mild tissue reaction along with some neovascularization.

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Isolation of humic acid from the terrestrial plant Brugmansia sanguinea

Cited by 16 publications

References 4 publications

Replenishing Humic Acids in Agricultural Soils

Replenishing Humic Acids in Agricultural Soils

Effects of humic acid fractions with different polarities on photodegradation of 2,4-D in aqueous environments

Characterization and Biocompatibility Studies of Novel Humic Acids Based Films as Membrane Material for an Implantable Glucose Sensor

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