Pengaruh pemanasan gelombang mikro dua tahap pada hidrolisis asam empulur sagu untuk produksi bioetanol

Abstract

Sago is a genus of palm that can be utilized to produce fermentable sugars as substrate for bioethanol. Sago pith is a heterogeneous substrate consists of starch and fiber. Acid hydrolysis by microwave heating radiation can break down starch and fibers together in a very short time, so it is considered to be very efficient. The use of microwave energy (as power level) and variation of heating time can produce fermentable sugar with certain characteristics. This study included the preparation of sago pith flour, pith composition analysis including proximate components, starch, and fiber components, the process of acid hydrolysis (0.3 M and 0.5 M sulphuric acid) with two steps microwave heating (power level 30% with time variation 1 minute, 2 minutes and 3 minutes the next step followed by power level 70% for 3 minutes), and characterization of fermentable sugar. As comparison, conventional treatment carried out using the autoclave on 121oC for 15 minutes. The highest sugar (105.7 g/l) contents of fermentable sugar is produced from microwave heating with power level 30% for 2 minutes followed by the power level 70% for 3 minutes. This hydrolyzate then used as substrate fermentation for Issatchenkia orientalis with different acidity (pH 3, 4 and 5), but highest ethanol produced from substrate with pH 5. Ethanol produced is still low (2.8 g/l) compared with autoclave treatment (14.5 g/). Not all sugar were consumed and it is proved that Issatchenkia orientalis only consumed glucose for growth and ethanol production.