Pseudomonas alcaligenes strain U-3,a bacterium capable of accumulating high toughness polyhydroxyalkanoate(PHA),was isolated from sludge.Given substrate composed of sugar,yeast extract and peptone,the biomass concentration and PHA content reach 19.58g/L and 10.82g/L in 44 hrespectively.The PHA polymer produced by strain U-3 was investigated by FT-IR,NMR,and Ubbelohde viscosity measurement.The results show that the produced polymer is homopolymer poly-β-hydroxypelargonate of which viscosity-average molecular...