Prerequisites and susceptibility of humic acids to microbial utilization and transformation - a review

• Published in: Archiv für Acker- und Pflanzenbau und Bodenkunde 2011-08, Vol.57 (5), p.445-454
• Main Authors: Filip, Zdenek Karel, Bielek, Pavol, Demnerova, Katerina
• Format: Article
• Language: English
• Subjects: Acids; Alkalis; Carbon sources; Decomposition; Humic acids; humic substances; Magnesium; Metal complexes; Metals; microbial transformation; microbial utilization; Natural environment; Nitrogen sources; Reviews; Silicic acid; Soil; Soils; Transformation
• ISSN: 0365-0340; 1476-3567
• DOI: 10.1080/03650340802172491

In the last decades, structural complexity and importance to natural environments of humic substances have been elucidated. Their persistence and/or susceptibility to biological decomposition, however, requires further research. Here we present a contribution on humic acids (HA) extracted by alkali from soils differing in metal contents. These compounds represent organic-mineral-metal complexes naturally occurring in soils. If exposed to microbial activities, especially in the absence of easily utilizable carbon and nitrogen sources, HA from arable soils with elevated metal contents or from a soil site near a magnesium re-working factory and heavily contaminated with this element, were found to support the microbial growth. Simultaneously, different structural transformations occurred in the HA. Furthermore, the FT-IR spectroscopic investigations indicated a loss in metal and silicate constituents from the HAs preparations.