Pink Pigmented Facultative Methylotrophic Bacteria Isolated from Fermented Philippine Shrimp Paste

Area of Science:

• Microbiology
• Food Science
• Fermentation Technology

Background:

• Pink pigmented facultative methylotrophic (PPFM) bacteria are widespread in various ecosystems.
• PPFM bacteria have not been extensively studied in food environments, particularly fermented foods.
• Philippine shrimp paste is a fermented food product with a unique microbial profile.

Purpose of the Study:

• To investigate the presence and diversity of PPFM bacteria in Philippine shrimp paste.
• To phenotypically and genotypically characterize PPFM bacteria isolated from shrimp paste.
• To explore the potential of *Methylobacterium* species in fermented food applications.

Main Methods:

• Isolation and cultivation of PPFM bacteria from Philippine shrimp paste.
• 16S rRNA gene sequencing for genus identification (*Methylobacterium*).
• Comprehensive phenotypic characterization (morphological, biochemical, physiological tests).
• Phylogenetic analysis to determine genetic relatedness and species identification.

Main Results:

• Thirteen PPFM bacterial isolates were obtained from shrimp paste, all identified as *Methylobacterium*.
• Phenotypic tests confirmed characteristic traits: pink colonies, Gram-negative rods.
• Isolates exhibited mesophilic and halotolerant properties, growing at 2% salt concentration.
• Phylogenetic analysis identified species including *M. populi, M. dankookense, M. lusitanum, M. radiotolerans*, and *M. zatmanii*.

Conclusions:

• This study confirms the presence and diversity of *Methylobacterium* (PPFM) bacteria in Philippine shrimp paste.
• The findings highlight a novel microbial resource within fermented foods.
• Further research is warranted to elucidate the functional roles of these *Methylobacterium* species in shrimp paste production.