HIGH-EFFICIENCY STYRENE BIODEGRADATION IN A BIPHASIC ORGANIC-WATER CONTINUOUS REACTOR

Styrene was degraded as sole source of carbon and energy by a selected bacterial community in a two-phase aqueous-organic medium (80%:20%, v ol/vol). Silicone oil was used to solubilize styrene, which is sparing ly soluble in water and to prevent its toxicity toward microorganisms. Preliminary studies with the mixed population in batch cultures indic ate that the specific activity and the maximum growth rate at optimal pH 6.0 were 46 mg . g-1 . h-1 and 0.15 h-1, respectively. In pH-regula ted chemostat cultures, styrene was degraded at dilution rates ranging from 0.05 to 0.20 h-1. Kinetic parameters and the proportion of each strain in the mixed culture were followed. At 0.20 h-1, only one strai n as compared to four initially present, remained in the medium. This strain Pseudomonas aeruginosa, degrades styrene with a specific activi ty of 293 mg . g-1 . h-1. Such results could lead to industrial treatm ent of waste gas or water polluted with styrene.