The vital functions of extracellular polymeric substances (EPS) have been well recognized in bioleaching of sulfide ores. However, no report is available about the role of EPS in bioleaching of spent catalyst. To completely and deeply understand the functions of EPS in bioleaching of spent catalyst, the generation behavior of EPS at various pulp densities during bioleaching was characterized by three-dimensional excitation-emission matrix (3DEEM), and its relevance with bioleaching performance and process parameters were analyzed using mathematical means. The results showed that the EPS contain humus-like substances as main component (>70%) and protein-like substances as minor component (<30%). Both total EPS and humus-like substances mainly keep growing over the whole duration of bioleaching at low pulp density of 5.0% or lower; whereas total EPS and humus-like fraction keep declining at high pulp density of 7.5% or higher. Among the total EPS and its components, humus-like substances only have a positive significant correlation with bioleaching efficiencies of both Co and Mo and affect bioleaching process more greatly due to greater correlation coefficient. Biofilm appears at the spent catalyst surface under 2.5% of pulp density mediated by EPS while no biofilm occurs at 10% of pulp density due to shortage of EPS, accounting for the great difference in bioleaching efficiencies between high and low pulp densities which are 48.3% for Mo and 50.0% for Co at 10% of pulp density as well as 75.9% for Mo and 78.8% for Co at 2.5% of pulp density, respectively.

细胞外聚合物（EPS）的重要功能已经在硫化矿的生物浸出中得到了很好的认识。但是，没有关于EPS在废催化剂生物浸出中的作用的报道。为了完全深入地了解EPS在废催化剂生物浸出中的功能，利用三维激发-发射矩阵（3DEEM）表征了生物浸出过程中各种纸浆密度下EPS的生成行为，并与生物浸出性能和工艺参数相关。使用数学方法进行分析。结果表明，EPS包含腐殖质样物质作为主要成分（> 70％）和蛋白质样物质作为次要成分（<30％）。总EPS和腐殖质样物质在整个生物浸出过程中都主要以5.0％或更低的低纸浆密度保持增长。而在7.5％或更高的高纸浆密度下，总EPS和类腐殖质含量不断下降。在总EPS及其组分中，腐殖质样物质仅与Co和Mo的生物浸出效率呈正相关，而由于相关系数更大，对生物浸出过程的影响更大。在EPS介导的纸浆密度低于2.5％的情况下，生物膜出现在废催化剂表面，而在10％的纸浆密度下，由于EPS的缺乏，没有生物膜出现，这解释了高和低纸浆密度之间生物浸出效率的巨大差异（48.3％）在纸浆密度为10％时，Mo的含量分别为Mo和Co的50.0％，在纸浆密度为2.5％的情况下，Mo的含量为75.9％，Co的含量为78.8％。在总EPS及其组分中，腐殖质样物质仅与Co和Mo的生物浸出效率呈正相关，而由于相关系数更大，对生物浸出过程的影响更大。在EPS介导的纸浆密度低于2.5％的情况下，生物膜出现在废催化剂表面，而在10％的纸浆密度下，由于EPS的缺乏，没有生物膜出现，这解释了高和低纸浆密度之间生物浸出效率的巨大差异（48.3％）在纸浆密度为10％时，Mo的含量分别为Mo和Co的50.0％，在纸浆密度为2.5％的情况下，Mo的含量为75.9％，Co的含量为78.8％。在总EPS及其组分中，腐殖质样物质仅与Co和Mo的生物浸出效率呈正相关，而由于相关系数更大，对生物浸出过程的影响更大。在EPS介导的纸浆密度低于2.5％的情况下，生物膜出现在废催化剂表面，而在10％的纸浆密度下，由于EPS的缺乏，没有生物膜出现，这解释了高和低纸浆密度之间生物浸出效率的巨大差异（48.3％）在纸浆密度为10％时，Mo的含量分别为Mo和Co的50.0％，在纸浆密度为2.5％的情况下，Mo的含量为75.9％，Co的含量为78.8％。