Methylobacterium extorquens strain P14, a new methylotrophic bacteria producing poly-beta-hydroxybutyrate (PHB)

Area of Science:

• Microbiology
• Bacterial Physiology
• Biochemistry

Background:

• Facultative methylotrophic bacteria play crucial roles in carbon cycling.
• Poly-beta-hydroxybutyrate synthesis is a common energy storage mechanism in bacteria.
• Understanding bacterial diversity and metabolic pathways is essential for ecological and biotechnological applications.

Purpose of the Study:

• To isolate and characterize a novel facultative methylotrophic bacterium.
• To determine the poly-beta-hydroxybutyrate synthesizing capabilities of the isolated strain.
• To elucidate the detailed biochemical and genetic properties of the new strain.

Main Methods:

• Isolation and cultivation of bacterial strains.
• Gram staining, motility tests, and pigment analysis.
• Gas chromatography for fatty acid composition analysis.
• High-Performance Liquid Chromatography (HPLC) for phospholipid analysis.
• Ubiquinone analysis.
• DNA-DNA hybridization for taxonomic identification.
• GC content determination of DNA.

Main Results:

• Isolation of strain P14, a gram-negative motile rod synthesizing poly-beta-hydroxybutyrate.
• Predominant fatty acid: cis-vaccenic acid (72%).
• Predominant phospholipids: phosphatidylcholine (45%), phosphatidylenthanolamine (27%), phosphatidylglycerol (17%).
• Main ubiquinone: Q-10.
• Cells utilize the icl-variant of the serine pathway.
• DNA GC content: 65 mole%.
• High DNA-DNA homology with the genus Methylobacterium.
• Strain identified as Methylobacterium extorquens strain P14.

Conclusions:

• Strain P14 represents a new isolate of Methylobacterium extorquens.
• The strain possesses a distinct fatty acid and phospholipid profile.
• Its metabolic pathway and ubiquinone composition are characteristic of methylotrophic bacteria.
• This characterization contributes to the understanding of Methylobacterium diversity and function.