摘要：

A new heteropolymer has been isolated by chloroform extraction of activated sludges supplied by the Greater Peoria Sanitary District and from the waste purification facility of an industrial grain-processing plant. The compound is a polyester with physical and chemical properties similar, but not identical, to those of poly-β-hydroxy-butyrate (PHB). The polyhydroxyalkanoate (PHA) is composed primarily of β-hydroxyvaleric and β-hydroxy-butyric acids, along with lesser amounts of higher molecular weight components. It melts at 97-100°C, whereas PHB melts at 160-170°C. Because PHA is soluble in hot 95% ethanol, it can be separated from the alcohol-insoluble PHB. Gas chromatographic analysis of products obtained by hydrogenolysis and by saponification of PHA has given evidence for a mixture of C4, C5 (major component), C6, and C7 components. Structural studies show PHA to be a new microbial polymer present in activated sludge.

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