Optimization of nitrogen source supply for enhanced biosynthesis and quality of poly(3 ‐hydroxybutyrate‐co‐3‐hydroxyvalerate) by extremely halophilic archaeon Haloferax mediterranei

This study aimed at investigating the impact of using inorganic (NH4Cl) and organic (yeast extract) as nitrogen sources onHaloferax mediterranei biomass formation, polyhydroxyalkanoate (PHA) accumulation, PHA composition on the monomeric level, PHA molecular mass, and PHA properties (thermal and mechanical). AbstractThe extreme halophilic archaeon,Haloferax mediterranei can accumulate polyhydroxyalkanoate (PHA) from different renewable resources. To enhance the biosynthesis and quality of PHA,H.  mediterranei cultivation media was optimized at different C/N ratios using glucose as the main carbon source. Three sets of media (yeast extract [YE], NH4Cl and combination of YE and NH4Cl) were prepared at different nitrogen concentrations to achieve C/N ratios of 9, 20, and 35, respectively. The media containing YE (organic nitrogen source) produced a higher growth rate ofH.  mediterranei than NH4Cl (inorganic source) at all tested C/N ratios. The highest PHA accumulation (18.4% PHA/cell dry mass) was achieved in a media that combined YE with NH4Cl at a C/N ratio of 20. Analysis of the produced polymers revealed the production of poly(3 ‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBHV) with different 3‐hydroxyvalerate (3HV) content. The polymers produced from YE and the combined media have greater 3HV content (10 mol%) than those polymers recovered from NH4Cl (1.5  mol%). Resultingly, PHBHV from YE and the combined media displayed reduced melting points at 144°C. The ni...

Source: MicrobiologyOpen - May 14, 2020 Category: Microbiology Authors: Diya Alsafadi, Othman Al ‐Mashaqbeh, Aya Mansour, Majd Alsaad Tags: ORIGINAL ARTICLE Source Type: research