Effects of dissolved organic matter derived from forest leaf litter on biodegradation of phenanthrene in aqueous phase

Abstract

Dissolved organic matter (DOM) released from forest leaf litter is potentially effective for the degradation of polycyclic aromatic hydrocarbons (PAHs), yet the inherent mechanism remains insufficiently elucidated. In this study, we investigated the effects of DOM derived from Pinus elliottii and Schima superba leaf litter on the degradation of phenanthrene by the phenanthrene degrading bacterium Sphingobium sp. Phe-1. DOM from different origins and at a large range of concentrations enhanced the degradation rate of phenanthrene. DOM derived from P. elliottii leaf litter decomposed for 12 months used at a concentration of 100mg/L yielded the highest degradation rate (16.9% in 36h) and shortened the degradation time from 48h to 24h. Changes in the composition of DOM during degradation as measured by EEMs-FRI showed that proteins and tyrosine in the DOM supplied readily available nutrients that stimulated biological activity of Phe-1, increasing its growth rate and catechol 2,3-dioxygenase activity. Simultaneously, fulvic acid and humic acid in the DOM enhanced phenanthrene bioavailability by increasing the solubility and mass transfer of phenanthrene, enhancing the uptake kinetics of Phe-1, and increasing the bacteria's direct access to DOM-associated phenanthrene. Humic acid was co-metabolized by Phe-1, resulting in further stimulation of phenanthrene degradation.

Structural characteristics, analytical techniques and interactions with organic contaminants of dissolved organic matter derived from crop straw: a critical review

“…18 Lin et al 19 found that DOM promoted the bioavailability of pyrene when the freely dissolved concentration of pyrene was kept constant. Also, as suggested by Cai et al, 20 DOM enhanced the bioavailability of phenanthrene by facilitating the microbial accessed to DOMphenanthrene complex. The enhancement of polyferric aluminum sulfate (PFAS) bioaccumulation by Daphnia magna aer addition of DOM at a low level was also found by Xia et al 21 Therefore, DOM is a key component of the global carbon cycle and it is considered as the most active chemical group in terrestrial and aquatic ecosystems with its contribution of natural ligands and adsorption carriers in the environment.…”

Humic Acid Can Enhance the Mineralization of Phenanthrene Sorbed on Biochars

“…Some studies, however, reported that DOM enhanced microbial degradation of HOCs, not only by stimulating microbial growth as a carbon source or microbial nutrient , but also by adjusting bacteria cell wall properties for internalizing HOCs, which eventually increased the bioactivity of the degrading strain. Another study documented that in a PHE degradation system where HA was present HA was cometabolized by the degrading bacteria during the PHE biodegradation process …”

Dissolved and particulate carbon export from a tropical mangrove‐dominated riverine system

“…comm., compared to Thailand mangroves: 1.4–1.7 mmol m −2 h −1 ; Poungparn et al 2012). Overall, it appears that high production of biomass OC would ultimately enrich DOM concentration in the pore water and swamp surface water by active leaching of plant‐derived organic acids (Cai et al 2017).…”