Abstract: This study examined the elimination of environmental hazards imposed by octylphenyl polyethoxylates (OPnEO).The experiment used sodium alginate (SA) and polyvinyl alcohol (PVA) as carriers,mixed bacteria L9 for degrading OPnEO effectively as the material,and adopted three different ways,namely SA,PVA,and PVA+SA,to immobilize the mixed bacteria L9 and study the mechanical and chemical stability of three kinds of L9 particles.The results showed that the mixed bacteria L9 particles immobilized by the combination of PVA and SA displayed the highest mechanical and chemical stability.Through Orthogonal Experiments,the optimal PVA+SA immobilization condition was obtained:the calcium chloride saturated boric acid solution with a mixture of 8.0% polyvinyl alcohol (PVA),1.0% sodium alginate (SA),and 2.0% crosslinking agent,with the volume of embedded bacteria and embedding agent at the ratio of 2:1 and the crosslinking time being 24 hours.The analysis of the degradation of OPnEO by the mixed bacteria L9 in both immobilized and free forms,and controlled by different environmental conditions (temperature,pH,and substrate concentration),showed that the immobilized mixed bacteria L9 had a wider tolerance range for the aforementioned environmental conditions,compared with those of the free mixed bacteria L9.Thus,our proposed method was found to maintain relatively stable biological activity during actual application and efficiently address the environmental pollution caused by OPnEO,which is used in tanning,detergent,pesticides,and other industrial uses.