Abstract

QUINTANAR-GOMEZ, Samuel et al. PRODUCTION OF MEDIUM CHAIN LENGTH POLYHYDROXYALKANOATES FROM Cupriavidus necator WITH BEESWAX HYDROLYZATES AS CARBON SOURCE. Rev. Int. Contam. Ambient [online]. 2018, vol.34, n.3, pp.467-474. ISSN 0188-4999.  https://doi.org/10.20937/rica.2018.34.03.09.

This study demonstrates that using beeswax hydrolyzates (Hw), short- or medium-chain-length polyhydroxyalkanoates (scl-mcl-PHA) can be obtained by a three stages fed-batch fermentation system. The fed batch fermentations were conducted with a strain of Cupriavidus necator. Glucose and ammonium sulphate as carbon and nitrogen sources, respectively, were used in a first and second culture stages. In the third stage (production of scl-mcl-PHA) a fresh medium was fed with Hw as a carbon source at a concentration of 5 g/L, obtaining 8.91 g/L of intracellular scl-mcl-PHA and 13.64 g/L of biomass, which resulted in 65.3 % w/w of scl-mcl-PHA. Using nuclear magnetic resonance, the presence of scl and mcl monomers, 3-hydroxybutyrate (3HB) and 3-hydroxydecanoate (3HD) was determined. The percentage of comonomer incorporation different to 3HB was 4.6 mol %. A glass transition temperature (Tg) of -50 ºC and a melting temperature (Tm) of 79.8 ºC were determined for the scl-mcl-PHA (3HB-co-3HDD).

Keywords : biopolymers; DSC; mcl-PHA; NMR; fed-batch fermentation.

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