Exploiting the natural poly(3-hydroxyalkanoates) production capacity of Antarctic Pseudomonas strains: from unique phenotypes to novel biopolymers
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<p>Extreme environments are a unique source of microorganisms encoding metabolic capacities that remain largely unexplored. In this work, we isolated two Antarctic bacterial strains able to produce poly(3-hydroxyalkanoates) (PHAs), which were classified after 16S rRNA analysis as Pseudomonas sp. MPC5 and MPC6. The MPC6 strain presented nearly the same specific growth rate whether subjected to a temperature of 4 °C 0.18 (1/h) or 30 °C 0.2 (1/h) on glycerol. Both Pseudomonas strains produced high levels of PHAs and exopolysaccharides from glycerol at 4 °C and 30 °C in batch cultures, an attribute that has not been previously described for bacteria of this genus. The MPC5 strain produced the distinctive medium-chain-length-PHA whereas Pseudomonas sp. MPC6 synthesized a novel polyoxoester composed of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate-co-3-hydroxydecanoate-co-3-hydroxydodecanoate). Batch bioreactor production of PHAs in MPC6 resulted in a titer of 2.6 (g/L) and 1.3 (g/L), accumulating 47.3% and 34.5% of the cell dry mass as PHA, at 30 and 4 °C, respectively. This study paves the way for using Antarctic Pseudomonas strains for biosynthesizing novel PHAs from low-cost substrates such as glycerol and the possibility to carry out the bioconversion process for biopolymer synthesis without the need for temperature control.</p>
Extreme environments are a unique source of microorganisms encoding metabolic capacities that remain largely unexplored. In this work, we isolated two Antarctic bacterial strains able to produce poly(3-hydroxyalkanoates) (PHAs), which were classified after 16S rRNA analysis as Pseudomonas sp. MPC5 and MPC6. The MPC6 strain presented nearly the same specific growth rate whether subjected to a temperature of 4 °C 0.18 (1/h) or 30 °C 0.2 (1/h) on glycerol. Both Pseudomonas strains produced high levels of PHAs and exopolysaccharides from glycerol at 4 °C and 30 °C in batch cultures, an attribute that has not been previously described for bacteria of this genus. The MPC5 strain produced the distinctive medium-chain-length-PHA whereas Pseudomonas sp. MPC6 synthesized a novel polyoxoester composed of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate-co-3-hydroxydecanoate-co-3-hydroxydodecanoate). Batch bioreactor production of PHAs in MPC6 resulted in a titer of 2.6 (g/L) and 1.3 (g/L), accumulating 47.3% and 34.5% of the cell dry mass as PHA, at 30 and 4 °C, respectively. This study paves the way for using Antarctic Pseudomonas strains for biosynthesizing novel PHAs from low-cost substrates such as glycerol and the possibility to carry out the bioconversion process for biopolymer synthesis without the need for temperature control.
Extreme environments are a unique source of microorganisms encoding metabolic capacities that remain largely unexplored. In this work, we isolated two Antarctic bacterial strains able to produce poly(3-hydroxyalkanoates) (PHAs), which were classified after 16S rRNA analysis as Pseudomonas sp. MPC5 and MPC6. The MPC6 strain presented nearly the same specific growth rate whether subjected to a temperature of 4 °C 0.18 (1/h) or 30 °C 0.2 (1/h) on glycerol. Both Pseudomonas strains produced high levels of PHAs and exopolysaccharides from glycerol at 4 °C and 30 °C in batch cultures, an attribute that has not been previously described for bacteria of this genus. The MPC5 strain produced the distinctive medium-chain-length-PHA whereas Pseudomonas sp. MPC6 synthesized a novel polyoxoester composed of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate-co-3-hydroxydecanoate-co-3-hydroxydodecanoate). Batch bioreactor production of PHAs in MPC6 resulted in a titer of 2.6 (g/L) and 1.3 (g/L), accumulating 47.3% and 34.5% of the cell dry mass as PHA, at 30 and 4 °C, respectively. This study paves the way for using Antarctic Pseudomonas strains for biosynthesizing novel PHAs from low-cost substrates such as glycerol and the possibility to carry out the bioconversion process for biopolymer synthesis without the need for temperature control.
Keywords
Antarctic Pseudomonas, Exopolysaccharide, Glycerol, Low temperature, Poly(3-hydroxyalkanoates), Psychrophiles, Antarctic Pseudomonas, Exopolysaccharide, Glycerol, Low temperature, Poly(3-hydroxyalkanoates), Psychrophiles