De Novo Assembly of the Polyhydroxybutyrate (PHB) Producer 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 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. 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 strain H1. The genome assembly is over 7.7 Mb in size, including a circular megaplasmid of approximately 456 Kbp. In addition to the 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 revealed the presence of and auxiliary genes in all species investigated, suggesting that the PHB production is a common feature of the genus. Based on sequence identity, we also suggest as the closest species to which the operon of the strain H1, reported in 1998, is similar.