Interactions between Humic Substances and Microorganisms and Their Implications for Nature-like Bioremediation Technologies

Abstract

The state of the art of the reported data on interactions between microorganisms and HSs is presented herein. The properties of HSs are discussed in terms of microbial utilization, degradation, and transformation. The data on biologically active individual compounds found in HSs are summarized. Bacteria of the phylum Proteobacteria and fungi of the phyla Basidiomycota and Ascomycota were found to be the main HS degraders, while Proteobacteria, Actinobacteria, Bacteroidetes, and Firmicutes were found to be the predominant phyla in humic-reducing microorganisms (HRMs). Some promising aspects of interactions between microorganisms and HSs are discussed as a feasible basis for nature-like biotechnologies, including the production of enzymes capable of catalyzing the oxidative binding of organic pollutants to HSs, while electron shuttling through the utilization of HSs by HRMs as electron shuttles may be used for the enhancement of organic pollutant biodegradation or lowering bioavailability of some metals. Utilization of HSs by HRMs as terminal electron acceptors may suppress electron transfer to CO2, reducing the formation of CH4 in temporarily anoxic systems. The data reported so far are mostly related to the use of HSs as redox compounds. HSs are capable of altering the composition of the microbial community, and there are environmental conditions that determine the efficiency of HSs. To facilitate the development of HS-based technologies, complex studies addressing these factors are in demand.

A Systematic Study of the Antioxidant Capacity of Humic Substances against Peroxyl Radicals: Relation to Structure

“…Over the past decade, a variety of natural polysaccharides have attracted great interest due to their antioxidant functions, responsible for wide-ranging beneficial therapeutic effects and health-promoting properties [ 40 , 41 ]. The content of carbohydrates in HS can reach 10% [ 42 ], which might represent their contribution to the antioxidant activity of humic materials.…”

Properties of Humic Acid Substances and Their Effect in Soil Quality and Plant Health

“…The use of humates as a remediation strategy has a number of advantages over the use of microorganisms, including increased soil water wetability, lower oxygen requirements, simplicity of application, and lower cost. [27][28][29]. During shortterm (45-day) experiments in mining and metallurgical places in the Kola Peninsula, Russia, the effects of exogenous coal humates, peat humates, and their combinations with nitrogen fixers and mycorrhizae forming fungi showed promising effects on Properties of Humic Acid Substances and Their Effect in Soil Quality and Plant Health DOI: http://dx.doi.org/10.5772/intechopen.105803 environmentally friendly and effective solutions for soil health restoration caused by long-term air pollution with sulphur dioxide and heavy metals.…”

Electron shuttles enhanced the removal of antibiotics and antibiotic resistance genes in anaerobic systems: A review

“…Humic substances are widespread in the environment and are the products of bio-microbial transformation after the death of plants, animals, microorganisms, etc. The composition of humic substances is extremely complex and mainly includes humic acid and fulvic acid ( Kelleher and Simpson, 2006 ), which are generally considered as a class of low molecules composed of aromatic, aliphatic, phenolic, quinone, and N-containing derivatives, covalently bound through C–C, C–O–C, and N–C bonds ( Sutton and Sposito, 2005 ; Kulikova and Perminova, 2021 ). Its abundant phenolic and quinone moieties play an important role in it.…”