|
|
Very High Gravity Ethanol Production Under Different Aeration Schemes |
ZI Li-han, LIU Chen-guang, WANG Na, YUAN Wen-jie, BAI Feng-wu |
School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116023, China |
|
|
Abstract Under very high gravity (VHG) ethanol fermentation, aeration is an essential operation parameter for yeast cell to improve the performance of ethanol production. Flocculating yeast was used to convert 300 g glucose/L medium under 5 aeration schemes, including non-aeration, controlled-aeration regulated by redox potential (ORP) at -150 mV and -100 mV, constant aeration by pumping air at the rate of 0.05 vvm and 0.2 vvm. ORP was monitored under all conditions and taken as a criterion to distinct anaerobic, microaerobic and aeraobic conditions. The results showed that anaerobic fermentation produced the least ethanol (119±1.5 g/L) and left the highest glucose in 72 h. Microaerobic fermentation achieved the accurate air supply depending on the real-time cell oxygen demand, which lead to higher ethanol concentration (131±1.8和125±1.7 g/L). Aerobic fermentation brought about a quick biomass formation, and corresponding fast substrate utilization. However, too large aeration rate like 0.2 vvm caused the low yield (decreased by 12.2%) due to the huge formation of biomass and by-product such as glycerol. On the other hand, the lost of ethanol by air flow was highest under this condition. Moreover, it was observed that the flocculation quantified was promoted by increasing the air supply. In order to undertake a comprehensive evaluation for ethanol production and flocculation characteristic under different aeration schemes, a series of radar plots were illustrated based on data normalization. Constant aeration at 0.05 vvm was the preferable aeration condition thanks to its performance balance at all investigated aspects.
|
Received: 04 March 2013
Published: 25 June 2013
|
|
|
|
[1] Mussatto S I, Dragone G, Guimaraes P M, et al. Technological trends, global market, and challenges of bio-ethanol production. Biotechnol Adv, 2010, 28(6):817-830.
[2] Farrell A E, Plevin R J, Turner B T, et al. Ethanol can contribute to energy and environmental goals. Science, 2006, 311(5760): 506-508.
[3] 刘晨光, 氧化还原电位调控的高浓度乙醇发酵及其机理研究. 大连: 大连理工大学, 2011. Liu C G. The effects of oxidoreduction potential on very high gravity ethanol fermentation and studies of underlying mechanisms. Dalian: Dalian University of Technology, 2011.
[4] Bai F W, Anderson W A, Moo-Young M. Ethanol fermentation technologies from sugar and starch feedstocks. Biotechnol Adv, 2008, 26(1): 89-105.
[5] Zhao X Q, Bai F W. Yeast flocculation: new story in fuel ethanol production. Biotechnol Adv, 2009, 27(6): 849-856.
[6] Lin Y H, Chien W S, Duan K J, et al. Effect of aeration timing and interval during very-high-gravity ethanol fermentation. Process Biochem, 2011, 46(4):1025-1028.
[7] Alfenore S, Cameleyre X, Benbadis L, et al. Aeration strategy: a need for very high ethanol performance in Saccharomyces cerevisiae fed-batch process. Appl Microbiol Biotechnol, 2004, 63(5): 537-542.
[8] Adler V, Yin Z, Tew K D, et al. Role of redox potential and reactive oxygen species in stress signaling. Oncogene, 1999, 18(45): 6104-6111.
[9] Dahod S K. Redox potential as a better substitute for dissolved oxygen in fermentation process control. Biotechnol Bioeng, 1982, 24(9): 2123-2125.
[10] Murray R K, Bender D A, Botham K M, et al. Harper’s Illustrated Biochemistry. New York: McGraw-Hill Companies, 26th ed. 2003.
[11] 喻扬, 王永红, 储炬, 等.控制发酵过程氧化还原电位优化酿酒酵母乙醇生产. 生物工程学报, 2007, 23(5): 878-884. Yu Y, Wang Y H, Chu J, et al. The influence of controlling redox potential on ethanol production by Saccharomyces cerevisiae. Chin J Biotechnol, 2007, 23(5): 878-884.
[12] Lin Y H, Chien W S, Duan K J. Correlations between reduction-oxidation potential profiles and growth patterns of Saccharomyces cerevisiae during very-high-gravity fermentation. Process Biochem, 2010, 45(5): 765-770.
[13] Liu C G, Lin Y H, Bai F W. Development of redox potential-controlled schemes for very-high-gravity ethanol fermentation. J Biotechnol, 2011, 153(1-2): 42-47.
[14] 王娜, 刘晨光, 袁文杰, 等, 氧化还原电位控制下自絮凝酵母高浓度乙醇发酵. 化工学报, 2012, 63:1168-1174. Wang N, Liu C G, Yuan W J, et al. ORP control on very high gravity ethanol fermentation by flocculating yeast. CIESC J, 2012, 63:1168-1174.
[15] Ge X M, Zhao X Q, Bai F W. Online monitoring and characterization of flocculating yeast cell flocs during continuous ethanol fermentation. Biotechnol Bioeng, 2005, 90(5): 523-531.
[16] Fornairon-Bonnefond C, Demaretz V, Rosenfeld E, et al. Oxygen addition and sterol synthesis in Saccharomyces cerevisiae during enological fermentation. J Biosci Bioeng, 2002, 93(2): 176-182.
[17] Liu C G, Lin Y H, Bai F W. Ageing vessel configuration for continuous redox potential-controlled very-high-gravity fermentation. J Biosci Bioeng, 2011, 111(1): 61-66.
[18] Liu C G, Lin Y H, Bai F W. A kinetic growth model for Saccharomyces cerevisiae grown under redox potential-controlled very-high-gravity environment. Biochem Eng J, 2011, 56(1-2): 63-68.
[19] Ansell R, Granath K, Hohmann S, et al. The two isoenzymes for yeast NAD+-dependent glycerol 3-phosphate dehydrogenase encoded by GPD1 and GPD2 have distinct roles in osmoadaptation and redox regulation. EMBO J, 1997, 16(9): 2179-2187.
[20] Hounsa C G, Brandt E V, Thevelein J, et al. Role of trehalose in survival of Saccharomyces cerevisiae under osmotic stress. Microbiology, 1998, 144(3): 671-680.
[21] Berovic M, Herga M. Heat shock on Saccharomyces cerevisiae inoculum increases glycerol production in wine fermentation. Biotechnol lett, 2007, 29(6): 891-894. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
|
Shared |
|
|
|
|
|
Discussed |
|
|
|
|