STABILITY OF TOLUENE OXIDATION BY PSEUDOMONAS-PUTIDA UNDER NUTRIENT DEPRIVATION

Toluene-induced cells of Pseudomonas putida NCIMB 11767 lost their abi lity to oxidise toluene within 300 h. under conditions of carbon/energ y or nitrogen deprivation ar 30 degrees C, while incubation at 4 degre es C improved the stability of this activity. Provision of inducing su bstrates (toluene or phenol) to nitrogen-deprived cells at 30 degrees C also enhanced the stability of toluene oxidation, whereas provision of a non-inducing carbon/energy source (ethanol) led to a total loss o f toluene oxidation within 160 h. Disappearance of toluene-induced pro teins, at different rates accompanied the loss of toluene oxidation in carbon-deprived cells. The data suggest that degradation of one or mo re of the major proteins of toluene metabolism determines the stabilit y of toluene oxidation in carbon-deprived cells, Around 40% of the who le-cell tolene oxidation rate was recoverable after cryopreservation ( - 20 degrees C under glycerol) of toluene-induced cells but most of th is recovered activity (86%) was associated with dead cells, These obse rvations may have important implications for the application of these toluene-induced cells as in situ bioremediation catalysts.