Poly-gamma-glutamic acid (gamma-PGA) is an anionic polymer of increasing industrial interest, composed of thousands of glutamic acid residues linked by gamma-glutamyl bonds. Secretion of the polymer into the medium confers a mucoid colony morphology to the Bacillus producer strains grown on LB agar plates. Although Bacillus subtilis possesses the functional biosynthetic pgs operon, containing four genes, laboratory strains do not have the ability to produce the polymer because pgs transcription is not active. We dissected the genetic elements involved in the conversion of laboratory non-producer strains into gamma-PGA producers and established that the synergic action of two gene products is required. The co-presence of the wild-type swrAA allele, a gene involved in swarming motility, and the hyperphosphorylated form of the transcriptional factor degU, belonging to the two-component system degS/degU, is sufficient to drive pgs transcription and gamma-PGA production.
Poly-gamma-glutamate production in Bacillus subtilis
OSERA, CECILIA;CALVIO, CINZIA;GALIZZI, ALESSANDRO
2009-01-01
Abstract
Poly-gamma-glutamic acid (gamma-PGA) is an anionic polymer of increasing industrial interest, composed of thousands of glutamic acid residues linked by gamma-glutamyl bonds. Secretion of the polymer into the medium confers a mucoid colony morphology to the Bacillus producer strains grown on LB agar plates. Although Bacillus subtilis possesses the functional biosynthetic pgs operon, containing four genes, laboratory strains do not have the ability to produce the polymer because pgs transcription is not active. We dissected the genetic elements involved in the conversion of laboratory non-producer strains into gamma-PGA producers and established that the synergic action of two gene products is required. The co-presence of the wild-type swrAA allele, a gene involved in swarming motility, and the hyperphosphorylated form of the transcriptional factor degU, belonging to the two-component system degS/degU, is sufficient to drive pgs transcription and gamma-PGA production.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.