Preparation and Activity of Immobilized Acetobacter suboxydans Cells

The possibility of immobilization of Acetobacter suboxydans cells by entrapment within polyacrylamide gels or by intercellular cross-linking with glutaral-dehyde was investigated. The oxidation of unsubstituted alditols and aldose diethyl dithioacetals by the resultant modified cells has been achieved.     

Phosphoenolpyruvate Carboxylation and Aspartate Synthesis in Acetobacter suboxydans

Dialyzed extracts of Acetobacter suboxydans ATCC 621 catalyze (14)CO(2) assimilation in the presence of phosphoenolpyruvate and a divalent cation. The formation of (14)C-oxalacetate was demonstrated and found not to be dependent upon the presence of orthophosphate or diphosphonucleotides. Oxalacetate synthesis was stimulated by orthophosphate and inhibited by aspartate. All attempts to demonstrate a reversible carboxylation mechanism have failed. (14)C-aspartate was synthesized when phosphoenolpyruvate, H(14)Co(3) (-), pyridoxal phosphate, and glutamate were added to dialyzed extracts. Chromatographic and spectrophotometric analyses and chemical degradation further demonstrate the presence of a reversible aspartate aminotransferase. The function of oxalacetate synthesis in a bacterium that reportedly lacks an operative tricarboxylic acid cycle is discussed.