Optimization of Production of Polyhydroxyalkanoates (PHAs) from Newly Isolated Ensifer sp. Strain HD34 by Response Surface Methodology

Petroleum-based plastics have become a big problem in many countries because of their non-degradability and that they microplastics the environment. This study focused on optimization production medium conditions polyhydroxyalkanoates (PHAs), which are biodegradable bioplastics accumulated microbial cells. Among 341 isolates from 40 composted soil samples, best isolate was HD34 strain, identified using morphological, molecular, biochemical methods. The results showed strain most closely related to Ensifer adhaerens LMG20216T, with 99.6% similarity. For response surface methodology, it exhibited an optimal containing 3.99% (w/v) potato dextrose broth (PDB) 1.54% D-glucose adjusted initial pH 9.0. optimum achieved under culture temperature 28 °C, inoculum size 2.5% (v/v), shaking speed 130 rpm for 5 days. highest PHA content, total cell dry weight, yield as 72.96% (w/w) 9.30 g/L, 6.78 respectively. extracted characterization studied gas chromatography, 1H NMR, FTIR, XRD. found polymer polyhydroxybutyrate (PHB) melting (Tm) degradation (Td) 173.5 °C 260.8