Analyzing the effect of pH on microalgae adhesion by identifying the dominant interaction between cell and surface

Area of Science:

• Biotechnology
• Materials Science
• Surface Chemistry

Background:

• Microalgae biofuel production relies on efficient photobioreactor design.
• Understanding microalgae adhesion is crucial for optimizing these systems.
• Liquid medium pH is a key factor influencing biological and material interactions.

Purpose of the Study:

• To elucidate the mechanism by which liquid medium pH influences microalgae adhesion.
• To identify the dominant interactions governing cell-substratum adhesion at varying pH.
• To provide insights for predicting and controlling microalgae adhesion in industrial applications.

Main Methods:

• Adhesion experiments were conducted using a flow chamber setup.
• Three microalgae species (freshwater Chlorella sp., marine Chlorella sp., N. oculata) were tested.
• Adhesion was observed on two substrata (PVC and glass) across a range of pH values.

Main Results:

• Freshwater Chlorella sp. adhesion to PVC and glass, and marine microalgae to glass, decreased with increasing pH due to Electrostatic (EL) interactions and zeta potential changes.
• Marine microalgae adhesion to PVC increased with pH, driven by Lewis acid-base (AB) interactions and surface free energy modifications.
• The dominant interaction (EL or AB) dictates the pH-dependent adhesion behavior.

Conclusions:

• The study successfully elucidated the pH-dependent adhesion mechanisms of microalgae.
• Identifying dominant cell-surface interactions is key to understanding pH influence.
• These findings have significant implications for optimizing photobioreactor design and microalgae cultivation.