Functionalized graphene oxide in microbial engineering: An effective stimulator for bacterial growth

Area of Science:

• Nanobiotechnology
• Microbial Engineering
• Surface Chemistry

Background:

• The interaction between graphene derivatives and microorganisms is not fully understood, particularly concerning biocompatible coatings.
• Investigating these interactions is crucial for advancing nanobiotechnology applications.

Purpose of the Study:

• To synthesize and evaluate the effects of polyethylene glycol (PEG)-functionalized graphene oxide (nGO-PEGs) on *Escherichia coli* (E. coli) growth and cellular processes.
• To explore the potential of these nanomaterials in microbial engineering.

Main Methods:

• Synthesis of three types of nano-GOs functionalized with PEG (nGO-PEGs) with varying PEGylation degrees.
• Investigation of the effects of nGO-PEGs on *E. coli* growth, cell cycle, DNA synthesis, and extracellular polymeric substance (EPS) secretion.
• Assessment of nGO-PEG (1:1) for enhancing recombinant protein production in engineered *E. coli*.

Main Results:

• One specific nGO-PEG (1:1), with a lower PEGylation degree, significantly stimulated *E. coli* growth, unlike unmodified GO or other nGO-PEGs.
• This stimulation was linked to accelerated FtsZ-ring assembly, shortened bacterial cell cycle Phase 1, increased DNA synthesis, and enhanced EPS secretion.
• nGO-PEG (1:1) treatment resulted in a remarkable (up to 6-fold) increase in recombinant protein production in engineered bacteria.

Conclusions:

• Surface chemistry, specifically PEGylation degree, critically modulates the interaction between nanomaterials and microorganisms.
• Functionalized GO can act as a novel positive regulator for microbial engineering, enhancing bacterial growth and productivity.
• This study presents a significant advancement in understanding nanomaterial-microorganism interactions and their application in biotechnology.