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Controlled autolysis facilitates the polyhydroxyalkanoate recovery in Pseudomonas putida KT2440.

Martínez V, García P, García JL, Prieto MA - Microb Biotechnol (2011)

Bottom Line: The development of efficient recovery processes is essential to reduce the cost of polyhydroxyalkanoates (PHAs) production.Our results demonstrate that the intracellular presence of PHA granules confers resistance to cell envelope.Conditions to control the cell autolysis in P. putida BXHL in terms of optimal fermentation, PHA content and PHA recovery have been set up by exploring the sensitivity to detergents, chelating agents and wet biomass solubility in organic solvents such as ethyl acetate.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biology Department, Centro de Investigaciones Biológicas, Madrid, Spain.

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Schematic localization of the Ejh holin, the Ejl endolysin and the Tol–Pal proteins in the cell envelope of P. putida strains. TolQ, TolR and TolA are cytoplasmic membrane proteins that form a complex in the cytoplasmic (inner) membrane (IM). TolQ is an integral inner membrane protein containing three transmembrane domains with two cytoplasmic regions. TolR and TolA are anchored to the cytoplasmic membrane leaving most of the protein exposed to the periplasm. Pal is an outer membrane (OM) peptidoglycan‐associated lipoprotein and forms a complex with TolB, which is a periplasmic protein. Ejh holin is a small membrane protein that oligomerizes in the IM to form ‘holes’ that allow the translocation of the Ejl endolysin to the peptidoglycan, where it degrades the cell wall and lyses the cell.
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f8: Schematic localization of the Ejh holin, the Ejl endolysin and the Tol–Pal proteins in the cell envelope of P. putida strains. TolQ, TolR and TolA are cytoplasmic membrane proteins that form a complex in the cytoplasmic (inner) membrane (IM). TolQ is an integral inner membrane protein containing three transmembrane domains with two cytoplasmic regions. TolR and TolA are anchored to the cytoplasmic membrane leaving most of the protein exposed to the periplasm. Pal is an outer membrane (OM) peptidoglycan‐associated lipoprotein and forms a complex with TolB, which is a periplasmic protein. Ejh holin is a small membrane protein that oligomerizes in the IM to form ‘holes’ that allow the translocation of the Ejl endolysin to the peptidoglycan, where it degrades the cell wall and lyses the cell.

Mentions: Our previous results indicated that cells expressing the ejh‐ejl cassette were more sensitive to outer membrane disturbing agents, such as chelating agents and detergents, when growing in rich medium than under optimal PHA production conditions in nitrogen limited minimal medium. Therefore, to improve the cell disruption for recovering PHA granules we tested a different strategy to alter the stability of the cell envelope. With this aim, we used tol‐pal mutants of P. putida KT2440 as recipients of the lytic system instead of wild‐type strain, because these mutants exhibit severe alterations in outer membrane integrity (Table 1). A comprehensive scheme of the Tol/Pal membrane proteins is depicted in Fig. 8.


Controlled autolysis facilitates the polyhydroxyalkanoate recovery in Pseudomonas putida KT2440.

Martínez V, García P, García JL, Prieto MA - Microb Biotechnol (2011)

Schematic localization of the Ejh holin, the Ejl endolysin and the Tol–Pal proteins in the cell envelope of P. putida strains. TolQ, TolR and TolA are cytoplasmic membrane proteins that form a complex in the cytoplasmic (inner) membrane (IM). TolQ is an integral inner membrane protein containing three transmembrane domains with two cytoplasmic regions. TolR and TolA are anchored to the cytoplasmic membrane leaving most of the protein exposed to the periplasm. Pal is an outer membrane (OM) peptidoglycan‐associated lipoprotein and forms a complex with TolB, which is a periplasmic protein. Ejh holin is a small membrane protein that oligomerizes in the IM to form ‘holes’ that allow the translocation of the Ejl endolysin to the peptidoglycan, where it degrades the cell wall and lyses the cell.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815265&req=5

f8: Schematic localization of the Ejh holin, the Ejl endolysin and the Tol–Pal proteins in the cell envelope of P. putida strains. TolQ, TolR and TolA are cytoplasmic membrane proteins that form a complex in the cytoplasmic (inner) membrane (IM). TolQ is an integral inner membrane protein containing three transmembrane domains with two cytoplasmic regions. TolR and TolA are anchored to the cytoplasmic membrane leaving most of the protein exposed to the periplasm. Pal is an outer membrane (OM) peptidoglycan‐associated lipoprotein and forms a complex with TolB, which is a periplasmic protein. Ejh holin is a small membrane protein that oligomerizes in the IM to form ‘holes’ that allow the translocation of the Ejl endolysin to the peptidoglycan, where it degrades the cell wall and lyses the cell.
Mentions: Our previous results indicated that cells expressing the ejh‐ejl cassette were more sensitive to outer membrane disturbing agents, such as chelating agents and detergents, when growing in rich medium than under optimal PHA production conditions in nitrogen limited minimal medium. Therefore, to improve the cell disruption for recovering PHA granules we tested a different strategy to alter the stability of the cell envelope. With this aim, we used tol‐pal mutants of P. putida KT2440 as recipients of the lytic system instead of wild‐type strain, because these mutants exhibit severe alterations in outer membrane integrity (Table 1). A comprehensive scheme of the Tol/Pal membrane proteins is depicted in Fig. 8.

Bottom Line: The development of efficient recovery processes is essential to reduce the cost of polyhydroxyalkanoates (PHAs) production.Our results demonstrate that the intracellular presence of PHA granules confers resistance to cell envelope.Conditions to control the cell autolysis in P. putida BXHL in terms of optimal fermentation, PHA content and PHA recovery have been set up by exploring the sensitivity to detergents, chelating agents and wet biomass solubility in organic solvents such as ethyl acetate.

View Article: PubMed Central - PubMed

Affiliation: Environmental Biology Department, Centro de Investigaciones Biológicas, Madrid, Spain.

Show MeSH
Related in: MedlinePlus