Empty fruit bunches (EFB) contain macro and micronutrients, so they can be used as compost. EFB takes a long time to be composted because it has high cellulose. Used cellulolytic bacteria decomposers are a solution to boost EFB composting. The goal of this research is to get cellulolytic bacteria with a high potential for accelerating composting and producing high-quality compost. The study used a completely randomized design with several types of cellulolytic bacteria and was repeated three times. Data is presented in qualitative and quantitative formats. The qualitative data were analyzed descriptively, the quantitative data were analyzed using analysis of variance, and the Honestly Significant Difference (HSD) test was run at a 5% significance level. Temperature, volume shrinkage, color, smell, C-organic, N-total, C/N ratio, and pH parameters of the compost were analyzed. The results showed that the application of cellulolytic bacterial isolates could improve the quality of OPEFB compost (in accordance with SNI Compost Quality Standards: 19-7030-2004) and speed up composting time. Consortium I was the best treatment with reduced compost volume up to 74.53%, decreased C-organic content up to 23.32%, increased total N content up to 1.88% and decreased C/N ratio up to 12.44.