Optimal Conditions for Spore-bound Laccase Production from Local Isolate of Bacillus subtilis*

Abstract

Fifty seven of bacterial isolates were isolated from different soils in different sites of AlDiwaniyah and Baghdad in Iraq using nutrient agar medium. The primary screening of bacterial isolateswas done on nutrient agar by dropping a few drops of syringaldazine on bacterial colonies proved that, only10 isolates were developed a pink color within 15 seconds. The secondary screening was done on nutrientbroth using syringaldazine as enzyme substrate proved that the isolate 54 developed the highest sporeboundlaccase activity (12.8) U/ml. The biochemical tests of bacterial isolate with highest laccase activityshowed that the bacteria are Bacillus subtilis. The optimization studies revealed that the maximum laccaseproduction was achieved when the production medium were at the following conditions: 3 days ofincubation, temperature 37 °C, pH 7.0, copper sulphate 0.2 mM, glucose as carbon source 3%, Tryptone asnitrogen source 0.2% , Kcl 1mM and pyrogallol 1mM as enzyme inducer , after these conditions the sporeboundlaccase activity was (439.23) U/ml.