Polyhydroxyalkanoates (PHA) from Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 isolated from Mariout salt lakes

El-malek, Fady Abd; Farag, Aïda M.; Omar, Sanaa H.; Khairy, Heba

doi:10.1016/j.ijbiomac.2020.07.258

Cited by 50 publications

(43 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Different types of PHAs, including homopolymers such as polyhydroxybutyrate (PHB) and copolymers like 3-hydroxybutyrate- co -3-Hydroxyvalerate, have been produced using both, the wildtype of Ralstonia eutropha and others as well as various recombinant microorganisms ( Chung et al, 2011 ; Gumel et al, 2012b ). Bacteria accumulate these polyesters as insoluble intracellular granules when they are cultivated under imbalanced conditions including excess carbon and limitation in nitrogen and phosphate ( El-Malek et al, 2020 ). Many carbon sources, such as alcohols, alkenes, alkanes, fatty acids and sugars can be utilized as feedstock, allowing the production of a wide range of polyesters and monomer units.…”

Section: Introductionmentioning

confidence: 99%

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

El-malek

Steinbüchel

2022

Front. Bioeng. Biotechnol.

Self Cite

View full text Add to dashboard Cite

Because of their biodegradability, compostability, compatibility and flexible structures, biodegradable polymers such as polyhydroxyalkanoates (PHA) are an important class of biopolymers with various industrial and biological uses. PHAs are thermoplastic polyesters with a limited processability due to their low heat resistance. Furthermore, due to their high crystallinity, some PHAs are stiff and brittle. These features result sometimes in very poor mechanical characteristics with low extension at break values which limit the application range of some natural PHAs. Several in vivo approaches for PHA copolymer modifications range from polymer production to enhance PHA-based material performance after synthesis. The methods for enzymatic and chemical polymer modifications are aiming at modifying the structures of the polyesters and thereby their characteristics while retaining the biodegradability. This survey illustrates the efficient use of enzymes and chemicals in post-synthetic PHA modifications, offering insights on these green techniques for modifying and improving polymer performance. Important studies in this sector will be reviewed, as well as chances and obstacles for their stability and hyper-production.

show abstract

Section: Introductionmentioning

confidence: 99%

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

El-malek

Steinbüchel

2022

Front. Bioeng. Biotechnol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…pacifica , although two recent reports have characterized polyhydroxyalkanoate production by a strain of H. pacifica isolated from salt lakes near Alexandria, Egypt [28, 29]. Further characterization of the H.…”

Section: Introductionmentioning

confidence: 99%

Utilization and accumulation of compatible solutes in Halomonas pacifica: a species of moderately halophilic bacteria isolated from a saline lake in South Libya

Abosamaha

Williamson

Gilmour

2022

Access Microbiology

View full text Add to dashboard Cite

When grown in high salt concentrations, halophilic bacteria often accumulate compatible solutes, which have major applications in biotechnology because they stabilize cells and proteins. Four Gram-negative bacterial strains, belonging to the family Halomonadaceae, were isolated from Qaberoun and Um-Alma lakes in South Libya using high-salinity medium. The strains were identified using 16S rRNA gene sequencing as belonging to Halomonas pacifica (strain ABQ1), Halomonas venusta (ABQ2), Halomonas elongata (ABU1) and Halomonas salifodinae (ABU2). H. pacifica ABQ1 is a moderate halophile (salinity range 0.05 to 2.5 M NaCl), with a broad tolerance to pH (7 to 9) and temperature (25–37 °C). Addition of the compatible solutes glycine betaine (betaine) and ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) to the medium had a positive effect on growth of H. pacifica at 2 M NaCl. In rich LB medium, betaine was the major compatible solute accumulated, with ectoine only being accumulated at salinities in excess of 1 M NaCl. In minimal M9 medium, betaine was not produced, but increasing amounts of ectoine were synthesized with increasing salinity, and hydroxyectoine [(4S,5S)−5-hydroxy-2-methyl-1,4,5,6-tetrahydropyrimidine-4-carboxylic acid] was also synthesized when the cells were grown in very high salt. We have thus identified H. pacifica as a producer of ectoine and hydroxyectoine, with more being produced at higher salinities. As industrial demand for these compatible solutes continues to increase, this system has biotechnological potential.

show abstract

“…Therefore, many approaches have been developed to minimize the production cost such as 1) the use of agricultural wastes and industrial by-products (e.g., fruit peels, bagasse, waste plant oils, crude glycerol, cheese whey, etc.) as inexpensive carbon sources with widespread availability and renewability ( Kulkarni et al, 2015 ; Patel et al, 2015 ; de Paula et al, 2017 ; Ray et al, 2018 :; Surendran et al, 2020 ), 2) the application of experimental designs and response surface methodology as statistical tools for the optimization of microbial biomass and PHA production using different cultivation modes (batch, fed-batch, and continuous fermentations) ( El-malek et al, 2020 ; Singh et al, 2021 ), 3) the use of extremophilic bacteria as efficient PHA-producing strains ( Cai et al, 2011 ; Yin et al, 2015 ; Kourmentza et al, 2017 ; Chen et al, 2018 ; Patel S. K. S. et al, 2021 ; Dubey and Mishra 2021 ). As an example, PHA production can be more environmentally friendly low-cost feed like using greenhouse gases (biogas) by thermophilic methanotrophs such as under non-sterile conditions ( Patel S. K. S. et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

“…TD-0, Halomonas sp. SF2003, Halomonas i4786, H. pacifica ASL10 and H. salifodiane ASL11 have been reported as promising candidates able to produce short chain length PHA up to 80 wt% of cell dry weight (CDW), using conventional carbon sources as well as carbonaceous by-products from food wastes ( Elain et al, 2016 ; El-Malek et al, 2020 ; Thomas et al, 2020 ; Dubey and Mishra, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Extremophilic Bacterium Halomonas desertis G11 as a Cell Factory for Poly-3-Hydroxybutyrate-co-3-Hydroxyvalerate Copolymer’s Production

Hammami

Souissi

Souii

et al. 2022

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

Microbial polyhydroxyalkanoates (PHA) are biodegradable and biocompatible bio-based polyesters, which are used in various applications including packaging, medical and coating materials. In this study, an extremophilic hydrocarbonoclastic bacterium, previously isolated from saline sediment in the Tunisian desert, has been investigated for PHA production. The accumulation of intracellular PHA granules in Halomonas desertis G11 was detected by Nile blue A staining of the colonies. To achieve maximum PHA yield by the strain G11, the culture conditions were optimized through response surface methodology (RSM) employing a Box-Behnken Design (BBD) with three independent variables, namely, substrate concentration (1–5%), inoculum size (1–5%) and incubation time (5–15 days). Under optimized conditions, G11 strain produced 1.5 g/L (68% of DCW) of PHA using glycerol as a substrate. Application of NMR (1H and 13C) and FTIR spectroscopies showed that H. desertis accumulated PHA is a poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). The genome analysis revealed the presence of typical structural genes involved in PHBV metabolism including phaA, phaB, phaC, phaP, phaZ, and phaR, coding for acetyl-CoA acetyltransferase, acetoacetyl-CoA reductase, class I polyhydroxyalkanoates synthases, phasin, polyhydroxyalkanoates depolymerase and polyhydroxyalkanoates synthesis repressor, respectively. Glycerol can be metabolized to 1) acetyl-CoA through the glycolysis pathway and subsequently converted to the 3HB monomer, and 2) to propionyl-CoA via the threonine biosynthetic pathway and subsequently converted to the 3HV monomer. In silico analysis of PhaC1 from H. desertis G11 indicated that this enzyme belongs to Class I PHA synthase family with a “lipase box”-like sequence (SYCVG). All these characteristics make the extremophilic bacterium H. desertis G11 a promising cell factory for the conversion of bio-renewable glycerol to high-value PHBV.

show abstract

Polyhydroxyalkanoates (PHA) from Halomonas pacifica ASL10 and Halomonas salifodiane ASL11 isolated from Mariout salt lakes

Cited by 50 publications

References 45 publications

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

Post-Synthetic Enzymatic and Chemical Modifications for Novel Sustainable Polyesters

Utilization and accumulation of compatible solutes in Halomonas pacifica: a species of moderately halophilic bacteria isolated from a saline lake in South Libya

Extremophilic Bacterium Halomonas desertis G11 as a Cell Factory for Poly-3-Hydroxybutyrate-co-3-Hydroxyvalerate Copolymer’s Production

Contact Info

Product

Resources

About