Potential of Ceiba pentandra (L.) Gaertn. (kapok fiber) as a resource for second generation bioethanol: Effect of various simple pretreatment methods on sugar production

► The chemical compositions of kapok fiber were changed after pretreatments. ► The impact of pretreatment on chemical composition was varied by the pH of medium. ► Pre-treatments significantly improved the enzymatic hydrolysability of kapok fiber. ► Alkaline pretreated fiber approached the maximum yield of reducing sugar production. ► Kapok fiber has high potential to be a new bio-resource for bioethanol production.