Bioengineered emulsans from Acinetobacter calcoaceticusRAG-1 transposon mutants

Area of Science:

• Microbiology
• Biochemistry
• Biotechnology

Background:

• Emulsan, a bioemulsifier produced by Acinetobacter calcoaceticus, has potential applications in various industries.
• Controlling the fatty acid (FA) composition of emulsan is crucial for optimizing its properties.

Purpose of the Study:

• To investigate the impact of gene disruptions on FA substitution patterns in emulsan.
• To characterize structural variants of emulsan produced by transposon mutants.
• To explore the bioengineering of microorganisms for tailored bioemulsifier production.

Main Methods:

• Generating transposon mutants of Acinetobacter calcoaceticus strain RAG-1.
• Disrupting genes involved in biotin, histidine, cysteine, and purine biosynthesis.
• Characterizing emulsan yield, FA content, molecular weight, and emulsification behavior.
• Supplementing growth media with fatty acids of varying chain lengths (C11-C18).

Main Results:

• Disrupted genes influenced the level and types of FAs incorporated into emulsan.
• Emulsan yields were lower in mutants than the parent strain and varied with supplemented FAs.
• Specific mutants (13D [His-] and 52D [Cys-]) showed enhanced emulsifying activity on C16 and C14 supplemented media, respectively.
• High percentages of C16 (48%) and C18 (42%) FAs on the polysaccharide backbone significantly influenced emulsification behavior.

Conclusions:

• Gene disruptions offer a method to control FA composition and emulsification properties of bioemulsifiers.
• Engineered Acinetobacter calcoaceticus strains can produce tailored emulsan variants.
• This research provides a pathway for developing novel amphipathic structures for environmental, biomedical, and personal care applications.