Restoring Polyhyrdoxybutyrate (PHB) Depolymerase Expression in a Bald Mutant of Streptomyces sp. SFB5A

Polyhydroxybutyrate (PHB) is a biodegradable, plastic-like polymer produced by some bacteria and degraded by others. The filamentous bacterium Streptomyces sp. SFB5A degrades PHB for growth using an extracellular PHB depolymerase, encoded by the phaZ gene. A morphological mutant of this bacterium, bld4, cannot form aerial filaments and cannot produce PHB depolymerase, despite having the phaZ gene. The inability to synthesize PHB depolymerase may be due to a mutation in a gene encoding one of its transcriptional regulators. A gene (lrp) coding for a potential transcriptional regulator is located 2,700 base pairs upstream from phaZ. Our goal was to clone lrp from wild type Streptomyces sp. SFB5A into Escherichia coli and introduce it into bld4 to see if morphology and PHB depolymerase synthesis are restored