Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

Biotechnology for Biofuels

Rishi Gupta¹  Sanjay Kumar²  James Gomes²  Ramesh Chander Kuhad¹ 

[1] Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India

[2] Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India

关键词: Bioethanol;    Delignified substrate;    Fermentation;    Kinetic model;    Fed-batch;    Enzymatic hydrolysis;   

Others  :  798340
DOI  :  10.1186/1754-6834-5-16

 received in 2012-01-10, accepted in 2012-03-20,  发布年份 2012

【 摘 要 】

Background

Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach.

Results

The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v) and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time.

Conclusion

Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates.

【 授权许可】

   
2012 Gupta et al; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Gupta R, Sharma KK, Kuhad RC: Separate hydrolysis and fermentation (SHF) of Prosopis juliflora, a woody substrate, for the production of cellulosic ethanol by Saccharomyces cerevisiae and Pichia stipitis-NCIM 3498. Bioresour Technol 2009, 100:1214-1220.
• [2]Kuhad RC, Gupta R, Khasa YP: Bioethanol production from lignocellulosics: an overview. In Wealth from waste. Edited by Lal B, Sharma PM. New Delhi, India: Teri press; 53-106.
• [3]Galbe M, Zacchi G: A review of the production of ethanol from softwood. Appl Microbiol Biotechnol 2002, 59:618-628.
• [4]Lynd LR, Laser MS, Bransby D, Dale BE, Davison B, Hamilton R, et al.: How biotech can transform biofuels. Nat Biotechnol 2008, 26:169-172.
• [5]Bansal P, Hall M, Realf MJ, Lee JH, Bommarius AS: Modeling cellulase kinetics on lignocellulosic substrates. Biotechnol Adv 2009, 27:833-848.
• [6]Zheng Y, Pan Z, Zhang R, Jenkins BM: Kinetic modeling for enzymatic hydrolysis of pretreated creeping wild ryegrass. Biotechnol Bioeng 2009, 102:1558-1569.
• [7]Hodge DB, Karim MN, Schell DJ, McMillan JD: Model-based fed-batch for high-solids enzymatic cellulose hydrolysis. Appl Biochem Biotechnol 2009, 152:88-107.
• [8]Kuhad RC, Gupta R, Khasa YP, Singh A: Bioethanol production from Lantana camara (red sage): Pretreatment, saccharification and fermentation. Bioresour Technol 2010, 10:8348-8354.
• [9]Chandra RP, Au-Yeung K, Chanis C, Roos AA, Mabee W, Chung PA, Ghatora S, Saddler JN: The influence of pretreatment and enzyme loading on the effectiveness of batch and fed-batch hydrolysis of corn stover. Biotechnol Prog 2011, 27:77-85.
• [10]Kristensen JB, Felby C, Jorgensen H: Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose. Biotechnol Biofuel 2009, 2:11. BioMed Central Full Text
• [11]Kuhad RC, Mehta G, Gupta R, Sharma KK: Fed batch enzymatic saccharification of newspaper cellulosics improves the sugar content in the hydrolysates and eventually the ethanol fermentation by Saccharomyces cerevisiae. Biomass Bioenergy 2010, 34:1189-1194.
• [12]Schell DJ, Farmer J, Newman M, McMillan JD: Dilute sulfuric acid pretreatment of corn stover in pilot-scale reactor. Appl Biochem Biotechnol 2003, 105-108:69-85.
• [13]Kadam KL, Rydholm EC, McMillan JD: Development and validation of a kinetic model for enzymatic saccharification of lignocellulosic biomass. Biotechnol Prog 2004, 20:698-705.
• [14]Capron M, Huusom JK, Sin G: Controlled fed-batch operation for improving cellulose hydrolysis in 2 G bioethanol production. 20th European Symposium on Computer Aided Process Ebgineering-ESCAPE20 2010.
• [15]Zhu Y, Malten M, Torry-Smith M, McMillan JD, Stickel JJ: Calculating sugar yields in high solids hydrolysis of biomass. Bioresour Technol 2011, 2011(102):2897-2903.
• [16]Wingren A, Galbe M, Zacchi G: Techno-economic evaluation of producing ethanol from softwood: comparison of SSF and SHF and identification of bottlenecks. Biotechnol Prog 2003, 19:1109-1117.
• [17]Aden A, Ruth M, Ibsen K, Jechura J, Neeves K, Sheehan J, Wallace B, Montague L, Slayton A, Lukas J: Lignocellulosic biomass to ethanol process design and economics utilizing co-current dilute acid prehydrolysis and enzymatic hydrolysis for corn stover. National Renewable Energy Laboratory Technical Report. NREL/TP-510-32438 2002.
• [18]Gupta R, Khasa YP, Kuhad RC: Evaluation of pretreatment methods in improving the enzymatic saccharification of cellulosic materials. Carbohydr Polym 2011, 84:1103-1109.
• [19]Chen M, Xia L, Xue P: Enzymatic hydrolysis of corncob and ethanol production from cellulosic hydrolysate. Int Biodeter Biodeg 2007, 59:85-89.
• [20]Ghose TK: Measurement of cellulase activity. Pure Appl Chem 1987, 59:257-268.