Application of encapsulated Penicillium variabile P16 in solubilization ofrock phosphate

Penicicllium variabile P16, encapsulated in agar or calcium alginate, produ ced gluconic acid in repeated batch shake-flask cultures. Agar-encapsulated mycelium produced 21% more gluconic acid than Ca-alginate-encapsulated fun gus, and was utilized in experiments for rock phosphate solubilization. The latter was closely related to gluconic acid production, which was affected by the presence of rock phosphate. Maximum amounts of dissolved P (0.226 g l(-1) batch(-1)) were found at 14.0 gl(-1) rock phosphate, but the solubili zation efficiency was higher at 3.5 gl(-1) rock phosphate. Gluconic acid pr oductivity pattern and the degree of,phosphate solubilization were not infl uenced by decreasing the glucose concentration in the cultivation medium fr om 80 to 25 gl(-1). Encapsulated fungal cells systems could substitute for chemical solubilization of rock phosphate and could be applied as soil micr obial inoculants. (C) 2000 Elsevier Science Ltd. All rights reserved.