Abstract: This paper studies the effect of root exudates and their fractions (amino acid, organic acid and reducing sugars) from Eichhornia crassipes on the growth, enzyme activity and phenol-degrading efficiency of Enterobacter sp. nov. The root exudates and their fractions at low concentrations (≤1%) show a stimulatory effect, but at high eoneentrations (≥10%), they inhibit the induction of phenol-degrading enzymes and reduce the efficiency of phenol-degradation while stimulate the growth of Enterobacter sp. nov. It is demonstrated that sugar fractions of root exudates are effective on phenoldegradation, and hence, it is possible to establish a phenol-degrading system with E. crassipes and Enterobacter sp. nov.

Key words: Eichhornia crassipes, Root exudates, Enterobacter sp. nov., Phenol-degradation