Aneurinibacillus thermoaerophilus CCM 8960 is a thermophilic bacterium isolated from compost in Brno. The bacterium accumulates polyhydroxyalkanoates (PHAs), a biodegradable and renewable alternative to petrochemical polymers. The bacterium reveals several features that make it a very interesting candidate for the industrial production of PHA. At first, due to its thermophilic character, the bacterium can be utilized in agreement with the concept of next-generation industrial biotechnology (NGIB), which relies on extremophiles. Second, the bacterium is capable of producing PHA copolymers containing a very high portion of 4-hydroxybutyrate (4HB). Such materials possess unique properties and can be advantageously used in multiple applications, including but not limited to medicine and healthcare. Therefore, this work focuses on the in-depth characterization of A. thermoaerophilus CCM 8960. In particular, we sequenced and assembled the genome of the bacterium and identified its most important genetic features, such as the presence of plasmids, prophages, CRISPR arrays, antibiotic-resistant genes, and restriction-modification (R-M) systems, which might be crucial for the development of genome editing tools. Furthermore, we focused on genes directly involved in PHA metabolism. We also experimentally studied the kinetics of glycerol and 1,4-butanediol (1,4BD) utilization as well as biomass growth and PHA production during cultivation. Based on these data, we constructed a metabolic model to reveal metabolic fluxes and nodes of glycerol and 1,4BD concerning their incorporation into the poly(3-hydroxybutyrate-co-4-hydroxybutyrate (P(3HB-co-4HB)) structure. KEY POINTS: • Aneurinibacillus sp. H1 was identified as Aneurinibacillus thermoaerophilus. • PHA metabolism pathway with associated genes was presented. • Unique monomer composition of produced PHAs was reported.

• Klíčová slova
• 4-hydroxybutyrate, Aneurinibacillus species H1, De novo assembly, Next-generation industrial biotechnology, PHA, Plasmid pAT1,
• MeSH
• Bacillales MeSH
• butylenglykoly MeSH
• glycerol MeSH
• kyselina 3-hydroxymáselná MeSH
• polyestery metabolismus   MeSH
• polyhydroxyalkanoáty * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• butylenglykoly MeSH
• glycerol MeSH
• kyselina 3-hydroxymáselná MeSH
• polyestery MeSH
• polyhydroxyalkanoáty * MeSH

Aneurinibacillus sp. H1 is a promising, moderately thermophilic, novel Gram-positive bacterium capable of the biosynthesis of polyhydroxyalkanoates (PHA) with tunable monomer composition. In particular, the strain is able to synthesize copolymers of 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB) and 3-hydroxyvalerate (3HV) with remarkably high 4HB and 3HV fractions. In this study we performed an in-depth material analysis of PHA polymers produced by Aneurinibacillus sp. H1 in order to describe how the monomer composition affects fundamental structural and physicochemical parameters of the materials in the form of solvent-casted films. Results of infrared spectroscopy, X-ray diffractometry and thermal analysis clearly show that controlling the monomer composition enables optimization of PHA crystallinity both qualitatively (the type of the crystalline lattice) and quantitatively (the overall degree of crystallinity). Furthermore, resistance of the films against thermal and/or enzymatic degradation can also be manipulated by the monomer composition. Results of this study hence confirm Aneurinibacillus sp. H1 as an auspicious candidate for thermophilic production of PHA polymers with material properties that can be tuned together with their chemical composition by the corresponding adjustment of the cultivation process.

• Klíčová slova
• Aneurinibacillus sp., P(3HB-co-3HV-co-4HB), P(3HB-co-4HB), crystallinity, polyhydroxyalkanoates, thermophiles,
• Publikační typ
• časopisecké články MeSH

Extremophilic microorganisms are considered being very promising candidates for biotechnological production of various products including polyhydroxyalkanoates (PHA). The aim of this work was to evaluate the PHA production potential of a novel PHA-producing thermophilic Gram-positive isolate Aneurinibacillus sp. H1. This organism was capable of efficient conversion of glycerol into poly(3-hydroxybutyrate) (P3HB), the homopolyester of 3-hydroxybutyrate (3HB). In flasks experiment, under optimal cultivation temperature of 45 °C, the P3HB content in biomass and P3HB titers reached 55.31% of cell dry mass and 2.03 g/L, respectively. Further, the isolate was capable of biosynthesis of PHA copolymers and terpolymers containing high molar fractions of 3-hydroxyvalerate (3HV) and 4-hydroxybutyrate (4HB). Especially 4HB contents in PHA were very high (up to 91 mol %) when 1,4-butanediol was used as a substrate. Based on these results, it can be stated that Aneurinibacillus sp. H1 is a very promising candidate for production of PHA with tailored material properties.

• Klíčová slova
• Aneurinibacillus sp., P(3HB-co-3HV-co-4HB), P(3HB-co-4HB), polyhydroxyalkanoates, thermophiles,
• Publikační typ
• časopisecké články MeSH