Engineering the bacterial shapes for enhanced inclusion bodies accumulation

Area of Science:

• Microbiology
• Biotechnology
• Cell Biology

Background:

• Bacteria accumulate various inclusion bodies like polyhydroxyalkanoates (PHAs).
• Engineering bacteria for enhanced inclusion body production requires larger intracellular volumes.
• Polyhydroxybutyrate (PHB) serves as a model inclusion body for accumulation studies.

Purpose of the Study:

• To investigate methods for increasing bacterial cell size for enhanced PHB accumulation.
• To identify genetic modifications that enlarge Escherichia coli (E. coli) for biotechnological applications.

Main Methods:

• Genetic manipulation of the mreB gene, encoding an actin-like protein essential for cell shape.
• Inducible expression of SulA, a protein that inhibits the FtsZ division ring.
• Combinatorial approaches involving mreB alterations and SulA induction in E. coli JM109SG.

Main Results:

• Deletion or altered expression of mreB led to increased bacterial cell size.
• Inducible SulA expression further enhanced cell enlargement.
• Overexpression of mreB in an mreB deletion mutant combined with SulA induction resulted in over 100% increase in PHB accumulation.
• Enlarged cell size correlated with a weakened cytoskeleton due to disrupted helical structures.

Conclusions:

• Bacterial cell enlargement strategies can significantly enhance inclusion body production.
• Targeting cytoskeletal proteins like MreB and division inhibitors like SulA offers a viable route for metabolic engineering.
• This approach holds promise for optimizing microbial factories for biopolymer synthesis.