2012 ©
             Publication
Journal Publication
Research Title Bioethanol production from sweet sorghum juice by Saccharomyces cerevisiae immobilized on sweet sorghum stalk under various fermentation systems 
Date of Distribution 1 March 2012 
Conference
     Title of the Conference 1st Asean Plus Three Graduate Research Congress 
     Organiser Graduate school, Chiang Mai University 
     Conference Place The Empress hotel 
     Province/State Chiang Mai, Thailand 
     Conference Date 1 March 2012 
     To 2 March 2012 
Proceeding Paper
     Volume
     Issue
     Page ST-17 
     Editors/edition/publisher  
     Abstract Bioethanol, an alternative to petroleum-based fuels, can be produced from biomass or sugar-yielding crops, i.e. sweet sorghum, by microorganisms. The use of cell immobilization system can minimize ethanol production costs because this system offers several advantages over free cell fermentation operation, i.e. higher yeast cell concentration resulting in higher fermentation rate, recycling utilization of the yeast and lower product inhibition. In this study, sweet sorghum stalks without peel were used as carriers for yeast (Saccharomyces cerevisiae NP 01) immobilization to produce ethanol from sweet sorghum juice containing 240 g l-1 of total sugar. The yeasts at the concentration of 1×108 cells ml-1 were immobilized on different sizes of the stalks (6×6×6 to 20×20×20 mm3) for 24 h before they were used for batch ethanol fermentation at 30 oC. The results showed that the stalk sizes did not affect batch ethanol production efficiencies. When the yeasts immobilized on the stalks were used in repeated-batch ethanol fermentation, they could be used for at least eight successive batches without any breakage. The average ethanol concentration (P), productivity (Qp) and yield (Yp/s) of the eight successive batches were 96.96 ± 7.75 g l-1, 1.33 ± 0.10 g l-1h-1 and 0.45 ± 0.02 g g-1, respectively. The sweet sorghum stalks with peel (6 to 20 mm in diameter and 6-mm thick) were also used as the carriers for cell immobilization. The ethanol production efficiencies of the yeasts immobilized on the stalks with peel were slightly lower than those of the stalks without peel. However, to minimize the carrier preparation time, the stalks with peel were further used as the carriers for cell immobilization to produce ethanol in continuous fermentation. The continuous system was carried out in a double tubular packed-bed bioreactor with 30% bed volume at the dilution rate of 0.013 h-1 and the total working volume of 1.56 l. The average P, Qp and Yp/s were 99.93 ± 1.13 g l-1, 1.30 ± 0.01 g l-1 h-1 and 0.47 ± 0.02 g g-1, respectively at the total fermentation time of 432 h. When the bed volume was increased to 50% and was used for the ethanol continuous fermentation under the same condition, the ethanol production efficiencies were similar to those of the 30% bed volume. The results obtained clearly demonstrated that the sweet sorghum stalks could be used as low-cost support materials for yeast cell immobilization to produce ethanol under both repeated-batch and continuous systems. 
Author
537160011-9 Mr. PONGTHEP ARIYAJAROENWONG [Main Author]
Technology Doctoral Degree

Peer Review Status มีผู้ประเมินอิสระ 
Level of Conference นานาชาติ 
Type of Proceeding Full paper 
Type of Presentation Oral 
Part of thesis true 
Presentation awarding false 
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