MECHANISMS OF SYNTHESIS AND UTILIZATION OF OXALATE INCLUSIONS IN THE COLORLESS SULFUR BACTERIUM MACROMONAS-BIPUNCTATA

The synthesis of calcium oxalate inclusions in Macromonas bipunctata i s mainly realized via oxalacetate conversion to acetate and oxalate wi th the participation of oxalacetate hydrolase. Three pathways of oxala te transformation catalyzed by different enzymes are possible. One of them leads to formation of glyoxylate, further involved in biosyntheti c reactions,the second one leads to oxalate oxidation to CO2 via forma te, which is essential in energy metabolism, and the third one, probab ly, is not involved in either biosynthetic or fueling reactions. Depen ding on the concentration of organic compounds in the medium, oxalates may appear as the ballast or serve as a pool of reserve organic matte r, which can maintain the bacterial metabolism under unfavorable condi tions.