This study investigated the effects of cellulolytic microbes (Bacillus subtilis, Aspergillus niger, Trichoderma harzianum and their combinations) and fermentation periods (20, 40 and 60 hr) on the detachment efficiency of palm oil fruits and the chemical properties of crude palm oil (CPO). Fermentation treatments significantly enhanced detachment efficiency by 5-22 times, increasing the number of detached fruits and empty bunches. The combination of B. subtilis and A. niger improved oil yield, while T. harzianum preserved β-carotene content. Both combinations also contributed to lowering free fatty acids (FFA). The highest oil yield (16.40%-28.60%) was achieved with a 20-hr fermentation, whereas longer durations (40 and 60 hr) resulted in lower yields of 13.90%-19.70% and 10.00%-14.40%, respectively. Compared to the control, fermentation treatments reduced moisture from 2.80% to 0.17%-2.46%, FFA from 3.43% to 0.45%-1.55% and β-carotene from 423.45 ppm to 135.2-373.9 ppm, while increasing the deterioration of bleaching index (DOBI) value. However, longer fermentation periods significantly (p<0.05) increased FFA, moisture and peroxide values while decreasing β-carotene and DOBI. In conclusion, combining B. subtilis with A. niger or T. harzianum for 20 hr of fermentation effectively enhances fruit detachment and improves CPO stability against oxidation.