The Acinetobacter outer membrane protein A (OmpA) is a secreted emulsifier.

Area of Science:

• Microbiology
• Biochemistry
• Environmental Science

Background:

• Acinetobacter strains are known for utilizing hydrophobic carbon sources and degrading oils.
• They produce bioemulsifiers to stabilize oil-in-water emulsions.
• A specific bioemulsifier, Alasan from Acinetobacter radioresistens KA53, involves a protein (AlnA) homologous to outer membrane protein A (OmpA).

Purpose of the Study:

• To investigate if the secretion of OmpA with emulsifying activity is a common trait among oil-degrading Acinetobacter strains.
• To analyze the ompA gene and protein structure in Acinetobacter species for emulsification potential.

Main Methods:

• Screening of five Acinetobacter strains for OmpA secretion.
• Cloning and sequencing of the ompA genes from Acinetobacter sp. ADP1 and Acinetobacter sp. V-26.
• Structural analysis of the deduced OmpA protein sequences.
• Expression and testing of recombinant OmpA proteins for emulsification activity in Escherichia coli.

Main Results:

• OmpA was found to be secreted in all five tested oil-degrading Acinetobacter strains.
• Sequence analysis revealed hydrophobic regions in the OmpA proteins crucial for emulsification.
• Recombinant Acinetobacter OmpA proteins demonstrated significant emulsifying capabilities.

Conclusions:

• The secretion of OmpA with emulsifying activity appears to be a general characteristic of oil-degrading Acinetobacter strains.
• This secreted OmpA likely plays a significant physiological role in the biodegradation of hydrophobic substrates, including hydrocarbons.