PlantView Support Phenanthrene Biodegradation Research: Enhanced phenanthrene degradation in microalgae-bacteria systems: Mechanistic roles of exogenous and indigenous degraders

New progress has been made in the biodegradation of phenanthrene pollutants using microalgae–bacteria symbiotic systems.

The research team led by Zhiling Yang from the Chinese Research Academy of Environmental Sciences published their findings in “Bioresource Technology” (IF = 9.0, JCR Q1 Top journal), a leading journal in the first quartile of environmental engineering.

This study provides a systematic understanding of the differential regulatory mechanisms governing antioxidant responses, extracellular polymeric substances, and microbial community metabolism in microalgae–bacteria symbiotic systems, offering a comprehensive technical approach for the green bioremediation of industrial polycyclic aromatic hydrocarbon (PAH)-containing wastewater.

Phenanthrene is a typical persistent and toxic polycyclic aromatic hydrocarbon (PAH). Biodegradation efficiency is low when a single microorganism is used, and the mechanisms underlying synergistic degradation by microalgae and bacteria have not been systematically compared. In this study, two Chlorella symbiotic systems were constructed using exogenous bacteria C.v-EB and indigenous bacteria C.v-IB, respectively, to elucidate the differential regulatory mechanisms of antioxidant responses, extracellular polymeric substances (EPS), and microbial community metabolism in the two types of symbiotic systems.

The study relied on multidimensional experimental analyses, including growth indicators, photosynthetic fluorescence, oxidative stress measurements, EPS characterization, metagenomics, and RT-qPCR, to investigate the mechanisms underlying synergistic degradation. After five days, the phenanthrene degradation rates in the two systems reached 75.3%–78.4%, while biomass increased by 17.2% and 75.0%, respectively. C.v-EB relied on enzymatic antioxidant defenses mediated by SOD/CAT and a high-protein EPS barrier to withstand stress. C.v-IB relied on non-enzymatic oxidative regulation involving glutathione and thioredoxin, forming dense biofilm-like EPS and coordinating microbial community degradation, defense, and transport pathways through quorum sensing. Metagenomic analysis revealed that indigenous microbial communities exhibited greater metabolic redundancy, employing multiple pathways to degrade phenanthrene and eliminate toxic intermediates, whereas exogenous microbial communities relied on a single pathway to achieve sustained and stable degradation. Significant differences were observed in microbial community assembly patterns: the exogenous system was dominated by deterministic factors, whereas the indigenous system was primarily characterized by neutral assembly.

Experiments using Plantview

In this study, the research team used the PlantView230F Plant Live Imaging System from Guangzhou Biolight Biotechnology Co., Ltd. to perform chlorophyll fluorescence imaging and measure the rapid light-response curves of Fv/Fm and relative electron transport rate (rETR), thereby quantifying changes in the photosynthetic physiology of Chlorella under phenanthrene stress.

DOI:10.1016/j.biortech.2026.135034