EFFECTS OF CULTURE PARAMETERS ON PENTACHLORONITROBENZENE REMOVAL BY SPOROTHRIX CYANESCENS

The ability of S. cyanescens to degrade high concentration of pentachl oronitrobenzene (PCNB 100mg/l or 0.34mM) was focused on ways to increa se or optimize rates of biodegradation. Experiments were conducted to examine the effects of several culture parameters on PCNB removal. The levels of PCNB in the medium were monitored by HPLC analysis over 5 d ays. Carbon, nitrogen were shown to strongly influence the extent of i ts removal. In these experiments, PCNB degradation best results were o btained under low concentrations in these elements corresponding, in t erm of chemical dose expressed as the ratio of the quantity of chemica l to the mass of mycelium inoculated, of a maximum value of 24.5 mu g/ mg. Moreover, S. cyanescens proved to perform a rather efficient degra dation (18.9 mu g/mg) when a complex carbohydrate, starch, was given a s the major carbon source. In parallel, the sensitivity of S. cyanesce ns to PCNB has been determined by measuring growth inhibition on PCNB supplemented solid media. In the range of chemical doses tested (0-150 mg/l), no lethal effects were observed.