Production of antifungal compounds by Pseudomonas aeruginosa K-187 using shrimp and crab shell powder as a carbon source

In addition to two bifunctional chitinases/lysozymes previously produced, Pseudomonas aeruginosa K-187 grown aerobically in a shrimp and crab shell powder medium produced anti-fungal compounds that in tests effectively inhibited 36 strains of fungi. Maximum inhibitory activity was obtained when P. aeruginosa K-187 was grown aerobically in a medium consisting of 4.75% shrimp and crab shell powder, 0.75% carboxymethyl cellulose, 0.1% K2HPO4, 0.05% MgSO4 7H(2)O, 0.3% NaCl, and 0.35% yeast extract at a pH of 6.0. The crude fungicide obtained from the culture broth of P. aeruginosa K-187 retained more than 90% of its inhibitory activities to Fusarium oxysporum even after being treated at a pH of 3 or 100 degrees C for 30 min. It also caused hyphal swelling and lysis in Fusarium oxysporum, a fact that might contribute to its suppression of damping-off disease in alfalfa caused by F. oxysporum. (C) 1999 Elsevier Science Inc. All rights reserved.