Optimization of environmental and nutritional conditions of oxalate degrading bacteria leading to high oxalate degrading activity

ABSTRACT

Bacterial that mineralize and/or convert oxalates to biomass was suggested as an important modulators in the biological carbon cycle. The mesophilic Burkholderia cepacia, isolated from Egyptian soil was tested for the secretion of oxalate decarboxylase. Nutritional conditions were investigated to optimize bacterial growth and oxalate decarboxylase production including different carbon and nitrogen sources, metal ions, substrate concentrations, in addition to different environmental factors such as the incubation time, pH, temperature, and agitation. The effect of Burkholderia cepacia on the urinary oxalate level in vitro and checking of plasmid DNA were also conducted. Optimum biomass and enzyme production were achieved using modified Schlegel's basal mineral medium containing 0.4% potassium oxalate after 72 hrs of incubation at 30[degree sign]C, pH 7-9 with 1 05 rpm agitation. Among the organic nitrogen sources investigated, ammonium nitrate found to be the best inducer of oxalate decarboxylase, while peptone repressed enzyme activity. Among the carbon sources tested, while peptone repressed enzyme activity. Among the carbon sources tested, inositol maximized the enzyme production. Zn[2+] enhanced oxalate decarboxylase activity, while Hg[2+] strongly inhibited enzyme production. Burkholderia cepacia exhibits good influence in diminishing the urinary oxalate level in idiopathic calcium oxalate urolithiasis patients. Burkholderia cepacia has a megaplasmid [genomic] DNA with a size of 12, 437.6 bp