Bioethanol Production from Cassava with Vinasse Recycle for Fermentation.

Abstract

Cassava tuber consists of starch and fibers that become potential substrate in ethanol fermentation. Starch and fibers should be converted into fermentable sugars by hydrolysis. Dilute acid hydrolysis is applied to convert both starch and fibers, increased the yield of simple sugars as fermentable sugars. Fermentation broth distillation produced ethanol as main product and vinasse as a liquid waste. Vinasse consists of remained sugars which is potential to reuse as new fermentation substrate. The objectives of this research are to analyze vinasse composition and investigate the proper treatment to recycle vinasse for fermentation. Ethanol content from fresh subtrate was 3.39%. Three recycles with ratio vinasse and fresh substrates of 40:60 was the most suitable treatment with fermentation efficiency 21.01% (third recycle). Vinasse recycle in ratio 40:60 decreased ethanol yield from 2.58% to 2.51% and finally 2.08% whereas water efficiency achieved 47.37% at first of recycle and 26.50% at third recycle.

Ubi kayu mengandung pati dan serat yang harus dipecah menjadi gula sederhana melalui proses hidrolisis sehingga dapat dikonversi oleh Saccharomyces cerevisiae menjadi etanol. Pemakaian asam pada proses hidrolisis diharapkan mampu menghidrolisis pati serta komponen serat secara bersamaan menjadi gula sederhana. Masih adanya gula yang tersisa dalam vinasse (sisa hasil destilasi) merupakan potensi untuk memanfaatkan vinasse menjadi media fermentasi baru. Penelitian ini bertujuan untuk mengkarakterisasi, melakukan daur ulang vinasse dengan rasio dan tingkat daur ulang tertentu sehingga didapatkan metode daur ulang yang menghasilkan kadar etanol yang terbaik setelah fermentasi.