This 24 h grown mother
culture (10 ml) was used to inoculate 50 ml of production medium containing
(w/v): glucose 6.00%, peptone 0.20%, groundnut meal 0.50%, zinc sulfate
0.03%, calcium carbonate 0.04%, and potassium dihydrogen phosphate 0.10%.
The pH of the medium was adjusted to 5.4 by HCl. Erlenmeyer flasks (500 ml)
containing 50 ml of medium were incubated at 28 8C in an orbital shaker at
240 rpm for 49 h. The 50-phosphodiesterase solution was harvested by centrifugation
at 4000 rpm at 4 8C for 10 min, and the supernatant thus obtained
was used as the crude enzyme preparation.