Changes in amino acids content of humic acids sequentially extracted from peat and sod–Podzolic soil

Abstract

Vialykh, E. A., Ilarionov, S. A., Abdelrahman, H. M. and Vialykh, I. A. 2014. Changes in amino acids content of humic acids sequentially extracted from peat and sod Á Podzolic soil. Can. J. Soil Sci. 94: 575Á583. Amino acids (AA) and peptides are thought to be part of humic acids (HA), but debate whether they are an integral part of the HA is still going. Humic acids sequentially extracted from peat and sod-podzolic soil were analyzed for their AA content, elemental composition and by Fourier transform infrared spectroscopy. Extracted HA were hydrolyzed in 6 M HCl for 16 h for AA release, which was detected by a capillary electrophoresis system. Alanine, arginine, sum of aspartic acid and asparagine, sum of cysteic acid and cysteine, sum of glutamic acid and glutamine, glycine, histidine, leucine and isoleucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, valine were identified. The total content of hydrolyzable AA in sod-Podzol HA increased by 6.2Á8.2% with increasing the extraction cycles while an inverse tendency was observed for AA released from peat HA. Moreover, individual AA expressed as percentages of total AA were constant values with coefficients of variation lower than 20% for the studied HA.Vialykh, E. A., Ilarionov, S. A., Abdelrahman, HJ. M. et Vialykh, I. A. 2014. Modification de la proportion d'acides amine´s dans les acides humiques extraits de fac¸on se´quentielle de la mousse de sphaigne et d'un podzol gazonne´. Can. J. Soil Sci. 94: 575Á583. On pense que les acides amine´s (AA) et les peptides entrent dans la composition des acides humiques (AH), mais la controverse sur le fait qu'ils en font partie inte´grante continue de faire rage. Les auteurs ont analyse´les acides humiques extraits successivement de la mousse de sphaigne et d'un podzol gazonne´en vue d'e´tablir leur teneur en AA, les e´le´ments les composant et leur spectroscopie IRTF. Les AH extraits ont e´te´hydrolyse´s dans du HCl 6 M pendant 16 h pour permettre la libe´ration des AA, lesquels ont e´te´de´tecte´s par un syste`me d'e´lectrophore`se capillaire. On a ainsi identifieĺ 'alanine, l'arginine, le me´lange d'acide aspartique et d'asparagine, le me´lange d'acide cyste´ique et de cyste´ine, le me´lange d'acide glutamique et de glutamine, la glycine, l'histidine, la leucine et l'isoleucine, la lysine, la me´thionine, la phe´nylalanine, la proline, la se´rine, la thre´onine, la tyrosine et la valine. La concentration totale d'AA hydrolysables dans les AH du podzol gazonne´augmente de 6,2 a`8,2 % avec la hausse du nombre de cycles d'extraction, les AA libe´re´s par les AH de la mousse de sphaigne suivant une tendance inverse. Par ailleurs, quand ils sont exprime´s sous forme de pourcentage des AA totaux, les AA individuels constituent une valeur stable dont le coefficient de variation est infe´rieur a2 0 % chez les AH examine´s.Abbreviations: DBE, double bond equivalents; HA, humic acid; AA, amino acid; FTIR, Fourier transform infraredCan.

Physicochemical Characterization and Antioxidant Activity of Humic Acids Isolated from Peat of Various Origins

“…This analysis indicated that HAp fractions differ from HAb fractions by having a higher content of aromatic structures and phenolic (aromatic OH) groups in the HA molecules, as estimated by the A 1610 /A 2920 and A 3400 /A 1610 ratios, respectively ( Figure 1 A,B). A 1610 , A 2920 , and A 3400 are optical densities for aromatic (C=C), aliphatic, and OH groups, respectively [ 42 , 43 ]. A plot of A 1610 /A 2920 versus E4:E6 demonstrated a negative linear correlation (r = −0.66; p < 0.03; n = 18), supporting the conclusion that the low E4:E6 ratio is indeed associated with aromatic components [ 41 ] ( Figure 1 C).…”

Amino Acids, Mineral Nutrients, and Efficacy of Vermicompost and Seafood and Municipal Solid Wastes Composts

“…These amino acids were part of the humic substances in the MSWC, SFWC, and the VC. The differences in the total and individual amino acid concentrations can be attributed to variations in the starting feedstock, the biodegradation process employed, the structure of the microbial community, and overall activities of hydrolyzing enzymes [23,24]. According to Fuentes et al [23], the composition of amino acids in compost may range between 4% and 20%.…”

“…Furthermore, Vialykh et al [24] suggested that variations in the composition of amino acids in soils and humic substances were due to the presence of wide range of amino acids in microbial biomass. This can explain the high amino acids content in the VC, that is, 40% greater than the SFWC and 85% greater than the thermophilically produced MSWC (Figure 1).…”