Various pretreatments on Ceiba pentandra (L) Gaertn. (kapok) fiber prior to enzymatic hydrolysis for sugar production were optimized in this study. The optimum conditions for water, acid, and alkaline pretreatments were 170 degrees C for 45 min, 120 degrees C for 45 min in 1.0% (v/v) H2SO4 solution and 120 degrees C for 60 min in 2.0% (v/v) NaOH solution, respectively. Among the three pretreatments, the alkaline pretreatment achieved the highest total glucose yield (glucose yield calculated based on the untreated fiber) (38.5%), followed by the water (35.0%) and acid (32.8%) pretreatments. As a result, the relative effectiveness of the pretreatment methods for kapok fiber was verified as alkali > water > acid at the condition stated. (C) 2013 Elsevier Ltd. All rights reserved.