Poly-β-hydroxybutyrate (PHB) production from domestic wastewater using Enterobacter aerogenes 12Bi strain

A strain of poly-beta-hydroxybutyrate (PHB)-accumulating bacterium was isolated and identified as Enterobacter aerogenes (designated E. aerogenes 12Bi) by using biochemical and phylogenetic characterization. The accumulation of a large amount of granules in its cells cultured in the domestic wastewater medium (DWWM) were showed by transmission electron microscopy (TEM). When PHB production by our strain was determined by Hypochlorite method, it was found that PHB production ranged from 16.66 to 96.25% (w/w). The highest PHB yield by our microorganism was up to 96.25% within 18 h in DWWM 5 (supplemented with 100% DWW). This is the first report of the use of DWW for production of PHB by E. aerogenes. The results obtained in the study demonstrated that PHB could be efficiently produced to a high concentration with high productivity by using DWWM as an inexpensive substrate. Thus, it can contribute to the reduction of high production cost of PHB.