Thermophilic bacteria isolated from compost as producers of polyhydroxyalkanoates

abstract

English

Polyhydroxyalkanoates (PHA) are microbial polyesters produced by many bacteria. PHAs are entirely biodegradable, biocompatible and renewable good alternatives to petrochemical polymers. Extremophilic microorganisms are organisms which live and reproduce under an extreme condition which can be physical (high pressure, low or high temperature) or chemical (low or high pH, salinity). Such conditions are crucial for reducing the cost of the bioprocess because the biotechnological process can be operated in semi- or non-sterile conditions. An original isolation protocol was designed for isolating the PHA accumulating bacteria from compost. It is based on the application of osmotic challenge for the selection of PHA producing bacteria since PHA granules protect bacteria against the adverse effect of osmotic stress. We also employed thermophilic conditions to isolate thermophilic PHA producers which were further tested and evaluated in terms of their PHA production ability. Growing and producing conditions were optimized (e.g. different carbon and nitrogen sources, cultivation temperature and precursors). The most promising thermophilic isolated was capable to produce up to 60 % of poly(3-hydroxybutyrate). Furthermore, it was also capable of incorporating 3-hydroxyvalareate and 4-hydroxybutyrate units into the polymer structure when the culture was supplied with the proper precursors.

polyhydroxyalkanoates; thermophiles; compost;

PERNICOVÁ, I.; NOVÁČKOVÁ, I.; KOUŘILOVÁ, X.; HERNÁNDEZ, N.; PRIETO, M.A.; OBRUČA, S.

25. 9. 2019

C.A.R.M.E.N.e.V.

Straubing, Germany

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