Poly(3-hydroxybutyrate) influences biofilm formation and motility in the novel Antarctic species Pseudomonas extremaustralis under cold conditions

Abstract

Polyhydroxyalkanoates (PHAs) are highly reduced bacterial storage compounds that increase fitness in changing environments. It has previously shown that polyhydroxybutyrate (PHB) accumulation is essential during the growth under cold conditions. In this work, the relationship between PHB accumulation and biofilm development at low temperature was investigated. P. extremaustralis, an Antarctic strain able to accumulate PHB, and its phaC mutant, impaired in the synthesis of this polymer, were used to analyze microaerobic growth, biofilm development, EPS content and motility. PHB accumulation increased motility and survival of planktonic cells in the biofilms developed by P. extremaustralis under cold conditions. Microaerobic conditions rescued the cold growth defect of the mutant strain. The PHB accumulation capability could constitute an adaptative advantage for the colonization of new ecological niches in stressful environments.

Polyhydroxyalkanoates

“…In this work, elimination of PHA synthesis was observed to decrease rhamnolipid synthesis but increase alginate production in the wild-type strain, while in an alginate over-producing strain this polymer was unaffected and rhamnolipid production was increased by eliminating PHA biosynthesis, thus suggesting that PHA biosynthesis and alginate biosynthesis were in competition for a common metabolic precursor. A similar result was observed in a PHB mutant strain of P. extremaustralis in biofilms developed under cold conditions, where the defect in PHB production resulted in an increase of EPS, suggesting that carbon molecules availability could redirect PHB production to other carbon polymers such as EPS (Tribelli & L opez, 2011). Interestingly, the regulation of genes involved in PHA biosynthesis in biofilms showed a spatial distribution similar to that of rhamnolipid biosynthesis genes (Campisano, Overhage, & Rehm, 2008).…”

“…Furthermore, under cold conditions, PHB accumulation was reported to increase motility and survival of planktonic cells in the biofilms developed by P. extremaustralis. In view of this, the capability to accumulate PHB could constitute an adaptive advantage for the colonization of new ecological niches in stressful environments (Tribelli & L opez, 2011).…”

Production of Polyhydroxyalkanoate (PHA) Biopolyesters by Extremophiles?

“…Later, the same authors sequenced the entire genome of the strain as in order to identify all genes responsible for PHA metabolism, adaptability to extreme environments, and degradation of toxic compounds. As a result, the first completely sequenced genome of a psychrophilic organism is reported [91]. Further, they investigated the strain´s potential for bioremediation, specifically for degradation of the eco-pollutant diesel.…”

Co-culture for lipid production: Advances and challenges

“…During the co-culture of algae for lipid production, dense culture is produced and velocity growth is relatively higher. Naturally, microalgae produce EPS and in case of co-culture systems, more interactions lead to large amounts of EPS, as a metabolic strategy to grow in unfavorable conditions (nitrogen deficiency required also for lipid synthesis) [42,43]. EPS production may eventually limit the mass transfer making nutrients and CO2 accessibility difficult.…”