Studies were carried out in a packed-bed column fermentor using coffee husk as substrate in order to verify a relationship between caffeine degradation and the respiration of Aspergillus sp. LPBx. Fermentation conditions were optimized by using factorial design experiments. The kinetic study showed that the caffeine degradation was related to the development of mold and its respiration and also with the consumption of reducing sugars present in coffee, husk. From the values obtained experimentally for oxygen uptake rate and CO2 evolved, we determined a biomass yield of 3.811 g of biomass/g of consumed O-2 and a maintenance coefficient of 0.0031 g of consumed O-2/(g of biomass(.)h). The maximum caffeine degradation achieved was 90%.