Abstract:Polyhydroxyalkanoates (PHAs) accumulation and carbon consumption by Ralstonia eutropha H16 were investigated in anaerobic fermentative liquid (AFL) of waste activated sludge (WAS). The WAS was fermented at 52℃ with a sludge retention time (SRT) of 48 hours in hydrolysis reactor to form AFL, in which the volatile fatty acids(VFAs) were feasible carbon source for PHAs synthesis. When acetic acid was the predominant component of VFAs in the AFL (C/N/P≈100/10/1,TOC=2881mg/L, acetic acid/total VFAs=36.1%), R. eutropha H16 could utilize acetic acid and n-butyric prior to other VFAs for cell growth and PHAs synthesis, and the major monomer of PHAs was hydroxybutyrate (HB). Propionic and n-valeric acid were utilized at 20~40 hours after inoculation as hydroxyvalerate (HV) monomer content increasing. The maximum PHAs content detected in the cells was 12.51% (dry weight) after 40-hour reaction, and then iso-butyric and iso-valeric acid were utilized but both PHAs synthesis and cell growth decreased. When iso-valeric acid was the predominant VFA in the AFL (C/N/P≈100/10/1, TOC=2358mg/L, iso-valeric acid/total VFAs=29.0%), the maximum PHAs content detected in the cells was up to 32.14% (dry weight) at 24-hour of growth and hydroxyvalerate (HV) was the major monomer of PHAs.