De Novo Assembly of the Polyhydroxybutyrate (PHB) Producer Azohydromonas lata Strain H1 Genome and Genomic Analysis of PHB Production Machinery

Polyhydroxybutyrate (PHB) is a biodegradable natural polymer produced by different prokaryotes as a valuable carbon and energy storage compound. Its biosynthesis pathway requires the sole expression of the <i>phaCAB</i> operon, although auxiliary genes play a role in controlling polymer accumulation, degradation, granule formation and stabilization. Due to its biodegradability, PHB is currently regarded as a promising alternative to synthetic plastics for industrial/biotechnological applications. <i>Azohydromonas lata</i> strain H1 has been reported to accumulate PHB by using simple, inexpensive carbon sources. Here, we present the first de novo genome assembly of the <i>A. lata</i> strain H1. The genome assembly is over 7.7 Mb in size, including a circular megaplasmid of approximately 456 Kbp. In addition to the <i>phaCAB</i> operon, single genes ascribable to PhaC and PhaA functions and auxiliary genes were also detected. A comparative genomic analysis of the available genomes of the genus <i>Azohydromonas</i> revealed the presence of <i>phaCAB</i> and auxiliary genes in all <i>Azohydromonas</i> species investigated, suggesting that the PHB production is a common feature of the genus. Based on sequence identity, we also suggest <i>A. australica</i> as the closest species to which the <i>phaCAB</i> operon of the strain H1, reported in 1998, is similar.