IMMOBILIZATION OF THE SURFACTANT-DEGRADING BACTERIUM PSEUDOMONAS C12B IN POLYACRYLAMIDE-GEL .3. BIODEGRADATION SPECIFICITY FOR RAW SURFACTANTS AND INDUSTRIAL-WASTES

The surfactant-degrading bacterium Pseudomonas C12B was immobilized in polyacrylamide gel beads and the specificity of the immobilized cells towards various surfactants was examined. Profiles of activity towards primary alkyl sulfates of chain lengths from C6 to C14 were very similar for free and immobilized cells and reflected the known specificities of the alkylsulfatase enzymes that initiate the degradation. Initial rates of surfactant disappearance were in the order alkyl sulfates > linear alkyl benzene sulfonates > alkyl ethoxy sulfates >> alkane sulfonates. Sulfate esters, but not sulfonates, were totally degraded within 48 h. Immobilized cells also removed surfactant from solutions containing raw alkyl ethoxy sulfate mixtures (used to formulate shampoos), diluted whole-shampoo formulations, and mixed balance-tank effluent containing waste shampoo, hair dyes, and permanent wave formulations from a hair products factory. Repeated exposure to these wastes in the presence of added basal salts showed that the immobilized cells retained at least 60% and 28% of their activity after 6-day and 13-day operating periods, respectively. Balance-tank effluent, while initially producing the lowest activity, also provided the greatest stability even in the absence of added basal salts. Broad substrate specificity for sulfated surfactants, coupled with good biocatalyst stability, suggested that this system offered considerable potential for on-site treatment of surfactant wastes.