Microwave Assisted Alkaline Pretreatment of Ramie Decortication Waste for Bioethanol Production

Abstract

Biofuel production nowadays is developed to change the fossil fuel. Among many raw materials for bioethanol production, lignocellulosic materials are promising alternative feedstocks. One of the lignocellulosic material that can be used for bioethanol production is ramie decortication waste (RDW). There are four steps in producing bioethanol from lignocellulosic materials, they are pretreatment, hydrolisis, fermentation and ethanol purification. Pretreatment is the first and important step. This process is aimed to liberate the cellulose from the lignin and at the same time to reduce the lignin content. In the pretreatment process, microwave can be used to reduce the time needed. In this present study, pretreatment process of ramie decortication waste were done using alkaline and microwave assisted. Two alkaline were used, NaOH and Ca(OH) as they represent single and double ion alkali. Ramie decortication waste were immersed in solution of each alkali (3%, 4%, 5%, 6% and 7% b/v) with rasio solid:liquid is 1:10. Solution is pretreated using microwave (power 30% from max power 399W) for 15 minutes. Filtrate is separated and the residue then analyzed its cellulose and lignin content. From the experiment, the result showed that microwave can help the pretreatment process by reducing the time needed. Among the two alkaline, 5% Ca(OH)2 gives the best result in reducing the lignin content (27,4%). SEM analysis also shows that microwave assisted alkali pretreatment can change the structure of samples.