Development of a Practical and Cost-Effective Medium for Bioethanol Production from the Seaweed Hydrolysate in Surface-Aerated Fermentor by Repeated-Batch Operation

Abstract

To develop a practical and cost-effective medium for bioethanol production from the hydrolysate of seaweed Sargassum sagamianum, we investigated the feasibility and performance of bioethanol production in CSL (cornsteep liquor)-containing medium, where yeast Pichia stipitis was used and the repeated batch was carried out in a surface-aerated fermentor. The optimal medium replacement time during the repeated operation was determined to be 36 h, and the surface aeration rates were 30 and 100 ml/min. Under these conditions, the repeatedbatch operation was successfully carried out for 6 runs (216 h), in which the maximum bioethanol concentrations reached about 11-12 g/l at each batch operation. These results demonstrated that bioethanol production could be carried out repeatedly and steadily for 216 h. In these experiments, the total cumulative bioethanol production was 57.9 g and 58.0 g when the surface aeration rates were 30 ml/min and 100 ml/min, respectively. In addition, the bioethanol yields were 0.43 (about 84% of theoretical value) and 0.44 (about 86% of theoretical value) when the surface aeration rates were 30 ml/min and 100 ml/min, respectively. CSL was successfully used as a medium ingredient for the bioethanol production from the hydrolysate of seaweed Sargassum sagamianum, indicating that this medium may be practical and cost-effective for bioethanol production.

Solid state fermentation (SSF)-derived cellulase for saccharification of the green seaweed Ulva for bioethanol production

“…Effect of different ionic liquids on cellulase activity (a) and stability (b) at 10% IL (v/v) concentration. 10,16,[33][34][35][36][37] and comparable [38,39] to earlier reported studies (Table 3).…”

An overview of algae bioethanol production

“…When the medium was replaced every 48 h, bioethanol was continuously produced for 200 h under repeated-batch fermentor culture, where the level of bioethanol production was about 9 g/L. Lee et al [85] investigated the feasibility and performance of bioethanol production from the hydrolysate of seaweed Sargassum sagamianum in cornsteep liquor-containing medium, where yeast Pichia stipitis was used, and the repeated batch was carried out in a surface-aerated fermentor. The optimal medium replacement time during the repeated operation was determined to be 36 h, and the surface aeration rates were 30 and 100 mL/min.…”

Two-Step Process Using Immobilized Saccharomyces cerevisiae and Pichia stipitis for Ethanol Production from Ulva pertusa Kjellman Hydrolysate

“…Total reducing sugar was measured using the dinitrosalicylic acid method [4], and ethanol concentration was measured by gas chromatography, as described previously [38]. In addition, glucose and xylose were measured by quantitative thin-layer chromatography (TLC), which has been described previously in detail [24].…”

“…The temperature, pH, and agitation speed were maintained at 30 o C, 5.0, and 200 rpm, respectively. The surface aeration protocol used has been described previously [24,26,37].…”

“…In our previous studies, we accomplished batch and repeated-batch ethanol production processes from the hydrolysates of rape stem [37] and seaweed (Sargassum sagamianum and Ulva pertusa Kjellman) hydrolysates using Pichia stipitis [24,25,38], in which the hydrolysates contained both glucose and xylose. Xylose was subsequently utilized after Pichia utilized the glucose.…”