Abstract：Using protoplast technology,the best conditions were investigated for the protoplast formation and regeneration about denitrifying phosphorus accumulating bacteria N14,by the fungus age,pretreatment of ampicillin sodium concentration,time,the concentration of lysozyme,enzymatic hydrolysis time,and temperature. The results showed that ampicillin sodium with 120 μg / m L were inserted into the bacterial suspension for6 h when the cultures were trained 28 h. At 38 degrees centigrade,lysozyme with 1 μg / m L enzymolysised cell walls would take 45 min. And then the cultures were trained for 48 h in solid regenerative medium. The rate of preparation and regeneration of N14 were 96. 7% and 40. 9%,respectively. The influence of enzymolysis time to regeneration rate is greater than that to preparation.

Keyword：denitrifying phosphorus accumulating organism N14;protoplast preparation;protoplast regeneration;enzymolysis;