Azotobacter beijerinckii

The 3-ketothiolase has been purified and investigated from several poly(3HB)-synthesizing bacteria including Azotobacter beijerinckii [10], Ral-stonia eutropha [11], Zoogloea ramigera [12], Rhodococcus ruber [13], and Methylobacterium rhodesianum [14]. In R. eutropha the 3-ketothiolase occurs in two different forms, called A and B, which have different substrate specificities [11,15]. In the thiolytic reaction, enzyme A is only active with C4 and C5 3-ketoacyl-CoA whereas the substrate spectrum of enzyme B is much broader, since it is active with C4 to C10 substrates [11]. Enzyme A seems to be the main biosynthetic enzyme acting in the poly(3HB) synthesis pathway, while enzyme B should rather have a catabolic function in fatty-acid metabolism. However, in vitro studies with reconstituted purified enzyme systems have demonstrated that enzyme B can also contribute to poly(3HB) synthesis [15]. 

Molasses Sugar industry Sucrose and its hydrolysis products (glucose and fructose) Azotobacter beijerinckii. Bacillus megaterium, rec. strains of Escherichia coli, Klebsiella oxytoca and Klebsiella aerogenes [54-56]... 

Senior PJ, Beech GA, Ritchie GAP, Dawes EA (1972) The role of oxygen limitation in the formation of poly-P-hydroxybutyrate during batch and continuous culture of Azotobacter beijerinckii. Biochem J 128 1193-1201... 

Azotobacter chroococcum Glucose Azotobacter beijerinckii Glucose Alcaligenes eutrophus Fructose Methylobacterium B3-Bp Methanol Pseudomonas AM-1 Methanol Bacillus cereus Glucose... 

Senior, P. J. and Dawes, E. A. (1973). The regulation of poly-b-hydroxybutyrate metabolism in Azotobacter beijerinckii. Biochemical Journal 134, 225-238. 

Senior PJ, Dawes EA (1973) The regulation of poly-beta-hydroxybutyrate metabolism in Azotobacter beijerinckii. Biochem J 134 225-238 Shan GF, Gong X, Chen WP, Chen L, Zhu MF (2011) Effect of multi-walled carbon nanotubes on crystallization behavior of poly(3-hydroxybutyrate-co-3-hydrox3walerate). Colloid Polym Sci 289 1005-1014... 

The pathways and enzymology of PHA synthesis and degradation have been studied in many organisms. PHB (actually poly-[R-3-hydroxybutyrate]) synthesis and degradation were shown to be the complementary parts of a cycle in R. eutropha and Azotobacter beijerinckii more than twenty years ago [29, 32]. Since then, synthesis of PH As other than PHB has been partly or completely elucidated in R. eutropha. In contrast, much less is known about A. latus. 

Senior P J, Dawes E A. (1971), Poly(/3-hydroxybutyrate) biosynthesis and the regulation of glucose metabolism in Azotobacter beijerinckii , Biochem J, 125, 55-66. 

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