Microbial community changes in biological phosphate-removal systems on altering sludge phosphorus content

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Enhanced biological phosphate removal (EBPR) systems are crucial for nutrient management in wastewater treatment.
• Understanding the microbial community structure is key to optimizing EBPR efficiency.
• Sludge phosphorus content is a critical factor influencing EBPR performance.

Purpose of the Study:

• To investigate the impact of varying sludge phosphorus (P) content on the microbial community structure of lab-scale enhanced biological phosphate removal (EBPR) systems.
• To correlate microbial community composition with EBPR activity.
• To identify key microbial populations associated with different P levels.

Main Methods:

• Biomarker analysis, including respiratory quinones and cellular fatty acids.
• Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes for microbial community profiling.
• Phylogenetic analysis of sequenced DNA fragments.

Main Results:

• Microbial community structures were similar in sludge with 8-12.3% P (good EBPR activity) but differed from sludge with 2% P (no EBPR activity).
• Major biomarkers included ubiquinones Q-8, Q-10, menaquinone MK-8(H4), and fatty acids C16:0, C16:1 omega9c, C18:1 omega11c.
• DGGE revealed distinct microbial profiles, with phylogenetic analysis showing shared and unique phylotypes between high and low P sludge.

Conclusions:

• Sludge P content significantly affects the composition and abundance of predominant microbial populations in EBPR systems.
• While specific phylotypes could not be definitively linked to EBPR, shifts in community structure were observed.
• Further research is needed to fully elucidate the role of specific microbes in EBPR.