Interconnection of Key Microbial Functional Genes for Enhanced Benzo[a]pyrene Biodegradation in Sediments by Microbial Electrochemistry

Abstract

Sediment microbial fuel cells (SMFCs) can stimulate the degradation of polycyclic aromatic hydrocarbons in sediments, but the mechanism of this process is poorly understood at the microbial functional gene level. Here, the use of SMFC resulted in 92% benzo[a]pyrene (BaP) removal over 970 days relative to 54% in the controls. Sediment functions, microbial community structure, and network interactions were dramatically altered by the SMFC employment. Functional gene analysis showed that c-type cytochrome genes for electron transfer, aromatic degradation genes, and extracellular ligninolytic enzymes involved in lignin degradation were significantly enriched in bulk sediments during SMFC operation. Correspondingly, chemical analysis of the system showed that these genetic changes resulted in increases in the levels of easily oxidizable organic carbon and humic acids which may have resulted in increased BaP bioavailability and increased degradation rates. Tracking microbial functional genes and corresponding organic matter responses should aid mechanistic understanding of BaP enhanced biodegradation by microbial electrochemistry and development of sustainable bioremediation strategies.

The Utility of Electrochemical Systems in Microbial Degradation of Polycyclic Aromatic Hydrocarbons: Discourse, Diversity and Design

“…In addition, Dechloromonas species (Betaproteobacteria) anaerobically degrade aromatic compounds (Yan et al, 2017), participate in electron transfer and abundantly inhabit on the anode of SMFC (Xu et al, 2019). Many other PYR degrading anaerobes were enriched in SMFC treated sediments, e.g., Mycobacterium (Actinobacteria) and Nevskia (Gammaproteobacteria) (Yan et al, 2017;Wang et al, 2018). In wastewater, Hyphomicrobium and Rhodoplanes (Alphaproteobacteria) directly take part in the PHE degradation via indigenous bioaugmentation (Li et al, 2018).…”

Isolation and characterization of a bacterial strain Hydrogenophaga sp. PYR1 for anaerobic pyrene and benzo[a]pyrene biodegradation

“…The detailed conditions of the instrument can be found in previous studies. [5][6][7][8] Recoveries rates of PAH (75.28-103.63%) were determined by adding the known concentration of standards solutions containing 16 priority PAH compounds. …”

“…5,6 Microbial degradation and transformation is a major process for HMW-PAH removal in sediments. 3,7,8 River sediments can be oxic under aerated water ow, but PAH-contaminated sediments usually become anoxic. 9 Oxic and anoxic conditions can be a major driver of ecological niche differentiation of bacteria involved in PAH biodegradation in sediments.…”

Functional potential and assembly of microbes from sediments in a lake bay and adjoining river ecosystem for polycyclic aromatic hydrocarbon biodegradation

“…Benthic microorganisms play a central role in the natural attenuation and bioremediation of PAH contamination from sediments (Acosta‐Gonzalez et al ., 2013; Himmelberg et al ., 2018; Yan et al ., 2019; Wang et al ., 2020). Moreover, the fate of PAHs in sediment environments depends strongly on microbial biodegradation potential (Yan et al ., 2012; Yan et al ., 2014; Yan et al ., 2017b). Thus, the rate at which organic carbon is degraded determines which of these fates dominates and has important implications in ecosystem functioning.…”