A Polyhydroxybutyrate-Producing Pseudomonas sp. Isolated from Antarctic Environments with High Stress Resistance

Abstract

Pseudomonas sp. 14-3, a strain that accumulates large quantities of polyhydroxybutyrate (PHB) when grown on octanoate, was isolated from Antarctic environments. This isolate was characterized on the basis of phenotypic features and partial sequencing of its 16S ribosomal RNA gene. Pseudomonas sp. 14-3 showed increased tolerance to both thermal and oxidative stress compared with three other Pseudomonas species. Stress tolerance of Pseudomonas sp. 14-3 was analyzed in polyhydroxyalkanoate accumulating and non-accumulating conditions, and increased levels of stress resistance were observed when PHB was produced. Pseudomonas sp. 14-3 was isolated from Antarctic regions, a habitat normally exposed to extreme conditions. An association between high PHB accumulation and high stress resistance in bacteria adapted to extreme environments is suggested.

The rhodanese RhdA helps Azotobacter vinelandii in maintaining cellular redox balance

“…This result represents a further proof that deletion of the rhdA gene makes A. vinelandii more prone to stress, as originally suggested by the observed (Cereda et al, 2007) early accumulation of polyhydroxybutyrate (PHB) in MV474. Accumulation of PHB is considered a 'cell survival mechanism' (Anderson and Dawes, 1990;Ayub et al, 2004), and the same A. vinelandii phenotype was observed as a consequence of inactivation of the cydR gene (Wu et al, 2001) coding for the transcriptional regulator CydR (GeneID: 7760921; Uniprot acc. no.…”

Anr, the anaerobic global regulator, modulates the redox state and oxidative stress resistance in Pseudomonas extremaustralis

“…This species shows high stress resistance and is able to synthesize large amounts of poly(3-hydroxybutyrate), the best-known member of a bacterial reserve polymers family known as polyhydroxyalkanoates (PHAs) (Ayub et al, 2004(Ayub et al, , 2009. PHAs are involved in bacterial survival under different stressful conditions (Ló pez et al, 1995;Kadouri et al, 2005).…”

“…Aerobic and microaerobic 24 h cultures were performed for each strain and sensitivity to H 2 O 2 was evaluated as described previously (Ayub et al, 2004) + ratios were quantified in the pellet fraction of triplicate 1 ml bioreactor culture samples. Samples were transferred to pre-cooled plastic tubes and the metabolic activity was quenched by immersion of the tubes in liquid N 2 .…”

Exploring biodegradable polymer production from marine microbes

“…PHAs are biopolymers that are beneficial to bacteria and environment; they are utilized as nutrient under stressful condition in rhizosphere, soil, and phyllosphere [175,179,[180][181][182][183], distribution of carbon sources [184][185][186][187], enhancing survival factors in stress condition; osmotic shock, solvent stress, UV irradiation, heat and cold, ethanol, H2O2, and desiccation [188][189][190][191][192][193]183,[194][195][196] and control exopolysaccharide production [197,198,191,192,199] play a vital role in different energy consuming pathways, chemotaxis, nitrogen fixation, cell motility and aerotaxis [200,51,183,201,202], formation of cyst, germination, and sporulation [203]. Despite the PAHs producing significant advances, bacterial inoculants currently received much attention in plant growth promotion or plant production [204].…”