Abstract
Acid and base saccharification (hydrolysis) are simple and direct ways to convert biomass into fermentable sugars to be used for the production of bioethanol as renewable liquid fuel. In this study, the marine green alga (Ulva fasciata) was converted to sugars by acid and base hydrolysis (Na OH, ammonium oxalate, HCL, and H2SO4) at different concentrations (1, 3, 5, 7 %) at 121 degrees C for one, two and three rounds in autoclave. Biological hydrolysis of alga was also done by bacterial growth and enzymatic hydrolysis of alga. The maximum amount of sugars was 700 +/- 26.10 mg sugar/g alga biomass Ulva fasciata at one round of autoclave with 3 % sulphuric acid. The sugar ratio was 640.96 +/- 9.6 mg sugar/g algal biomass Ulva fasciata that treated by a bacterial strain (Bacillus subtilis SH04). Sugar yields from Ulva fasciata by amylase partially purified from Bacillus subtilis SH04 (B4) and Bacillus cereus SH06 (B6) followed by auto-claving for one round gave 458.27 +/- 6.55 and 516.07 +/- 5.17 mg sugar/g algal biomass, respectively. The ethanol efficiency using Saccharomyces cerevisiae SH02 was 78.3 % +/- 6 with 5 % sugar concentration that produced by acid hydrolysis. Ethanol production was 55.9 % +/- 5.2 after enzymatic hydrolysis of alga and fermentation by Saccharomyces cerevisiae SH02.