Proteins causing membrane fouling in membrane bioreactors

Area of Science:

• Environmental Science
• Biotechnology
• Chemical Engineering

Background:

• Membrane fouling is a significant challenge in membrane bioreactors (MBRs).
• Understanding the specific proteins involved in fouling is crucial for developing effective mitigation strategies.
• Real municipal wastewater presents complex fouling challenges due to its diverse composition.

Purpose of the Study:

• To identify and characterize the proteins responsible for membrane fouling in pilot-scale MBRs.
• To compare protein fouling profiles between submerged and side-stream MBR configurations.
• To elucidate the role of specific protein types in MBR membrane fouling.

Main Methods:

• Continuous operation of two pilot-scale MBRs (submerged and side-stream) with real municipal wastewater.
• Extraction and enrichment of foulants from fouled membranes using ultrafiltration and trichloroacetic acid precipitation.
• Separation and identification of proteins via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and N-terminal amino acid sequencing.

Main Results:

• Identified OmpA family protein (Brevundimonas/Riemerella anatipestifer) in submerged MBR foulants.
• Identified OprD and OprF proteins (Pseudomonas) in side-stream MBR foulants.
• All identified proteins belonged to the beta-barrel protein family, regardless of MBR type or operating conditions.

Conclusions:

• Beta-barrel proteins play a critical role in membrane fouling within MBRs.
• The findings highlight the importance of targeting beta-barrel proteins for fouling control in MBR technology.
• This research provides valuable insights into the molecular mechanisms of MBR membrane fouling.