Enhancement of bioethanol production from Ulva fasciata by biological and chemical saccharification

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 H 2 SO 4 ) at different concentrations (1, 3, 5, 7 %) at 121°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 autoclaving 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.

Batch bioethanol production via the biological and chemical saccharification of some Egyptian marine macroalgae

“…; Hamouda et al . ), but in this study, whole cells of five fungal strains, A. niger ATCC 16404, Fusarium sp. HN2, Penicellium sp.…”

“…) has been reported also by Hamouda et al . () during the basic hydrolysis of Ulva fasciata , where the thermo‐acid‐hydrolysis with HCl and H 2 SO 4 produced higher sugar yields than that of basic hydrolysis using NaOH. Wang et al .…”

“…The recorded bioethanol yield in the consortium culture was higher than that previously reported by Hamouda et al . () who recorded bioethanol production of 55·97% from the enzymatic hydrolysis of the green Ulva fasciata followed by the bioethanol fermentation of the hydrolysate with Saccharomyces cerevisiae SH02.…”

“…The bioethanol yield was calculated according to Hamouda et al . ():where TRS are the total reducing sugars measured by DNS method.…”

“…green seaweeds) have been evaluated for their energetic importance as a biofuel (Hamouda et al . , , ; El‐Sayed et al . ).…”