Biosynthesis and Characteristics of Polyhydroxyalkanoates. 1. Polyhydroxybutyrates of Azotobacter vinelandii N-15

Abstract

The biosynthesis of cellular polymers of Azotobacter vinelandii N-15 strain using molasses as a carbon source has been optimized. The highest yield of polymer (25.8 % of cell mass) was obtained on a nutrient medium with a molasses concentration of 50 g/l. Using TL-chromatography and IR-spectroscopy the obtained product was identified as polyhydroxybutyrate (PHB), and its properties were investigated. The wetting contact angle was used to characterize the biopolymer film surface properties. According to the results of thermal and thermomechanical studies, it was found that the obtained РHB is characterized by a high thermal stability and heat resistance: the melting point is 462 K; deep destruction and thermooxidative processes begin at the temperatures above 567 K.