Keywords
Hydrolysis
Saccharification
Pretreatment
Biomass
Fermentation
Abstract
Background: Bio-ethanol is a renewable, clean-burning liquid fuel with minimal environmental impact compared to petroleum-based alternatives. It can be produced from various organic wastes using either chemical or biological methods. While ethene from fossil sources can be hydrated to form ethanol, fermentation of sugar-rich feedstocks remains a viable alternative.
Purpose: This study aims to produce bio-ethanol from agricultural residues and organic wastes, specifically rice husk, biochar, Spirogyra, and seaweed using acid and base hydrolysis.
Methods: Rice husks were sourced from Effium Rice Mill, Ohaukwu (Ebonyi State, Nigeria), with a portion converted into biochar via pyrolysis at the Alex Ekwueme Federal University Ndufu-Aliki Ikwo Biotechnology Laboratory. Spirogyra and seaweed were collected from Okpuitumo Dam, Ikwo (Ebonyi State), thoroughly washed, oven-dried, pulverized, and sieved to uniform particle size (250 mm). Samples were characterized to determine lignin, cellulose, hemicellulose, and lignocellulose content. Pretreatment, hydrolysis, saccharification, and fermentation processes were conducted to evaluate ethanol yield.
Results: Acid hydrolysis using 1 mol/dm³ hydrochloric acid yielded the highest ethanol output (59.53%) compared to 1 mol/dm³ sodium hydroxide. Among the substrates, seaweed and Spirogyra showed the highest bio-ethanol yields at 59.53% and 41.88%, respectively.
Conclusion: Algal biomass, particularly seaweed and Spirogyra, represents a high-potential, underutilized resource for bio-ethanol production. Acid-mediated hydrolysis is especially effective and should be further explored for sustainable biofuel generation.
References
Acharya DK. Optimisation for cellulase production by Aspergillus niger using saw dust as substrate. Afr J Biotechnol. 2008;7(22):102-127.
Agbogbo FK, Coward-Kelly G, Torry-Smith M, Wenger KS. Fermentation of glucose/xylose mixtures using Pichia stipitis. Process Biochem. 2006;41:2333-2336.
Ali Z, Hussain M, Arshad M. Saccharification of corn cobs: Agro-industrial waste by sulphuric acid for the production of monomeric sugars. Int J Biosci. 2014;5(3):204-213.
Alicia M. Sodium hydroxide pre-treatment of corn stover and subsequent enzymatic hydrolysis: An investigation of yields, kinetic modeling and glucose recovery. Biosyst Agric Eng. 2013;5(1):420-425.
Araque EC, Parra M, Rodriguez J. Selection of thermo tolerant yeast strains Saccharomyces cerevisiae for bio-ethanol production. Enzyme Microb Technol. 2008;43:120-123.
Badger PC, Janick J, Whipkey A. Ethanol from cellulose: A general review. Trends New Crops New Uses. 2002:17-21.
Ballesteros I, Ballesteros M, Sáez F, Negro MJ, Manzanares P. Optimizing liquid hot water pretreatment conditions to enhance sugar recovery from wheat straw for fuel-ethanol production. Fuel. 2008;87(17-18):3640-3647.
Bowyer JL, Shmulsky R, Haygreen JG. Forest Product and Wood Science: An Introduction. Ames, IA: Blackwell Publishing; 2003:558.
Bowyer L, Shmulsky R, Haygreen JG. Forest Products and Wood Science: An Introduction. 5th ed. Ames, IA: Blackwell Publishing; 2007:558.
Chen F, Dixon RA. Lignin modification improves fermentable sugar yields for biofuel production. Nat Biotechnol. 2007;25:759–761.
Chiang VL. From rags to riches. Nat Biotechnol. 2002;20:557-558.
Crutzen PJ. N2O release from agro-biofuel production negates global warming reduction by replacing fossil fuels. Atmos Chem Phys. 2008;8:389.
Demirbas A. Biofuels sources, biofuel policy, biofuel economy and global biofuel projections. Energy Convers Manage. 2008;49:2106.
Galbe M, Zacchi G. Pretreatment of lignocellulose materials for efficient bio-ethanol production. Adv Biochem Eng Biotechnol. 2007;108:41–65.
Goldemberg J. Ethanol for a sustainable energy future. Science. 2007;315:808-810.
Gupta R, Sharma KK, Kuhad RC. Separate hydrolysis and fermentation (SHF) of Prosopis juliflora, woody substrate for the production of cellulosic ethanol by Saccharomyces cerevisiae and Pichia stipitis NCIM 3498. Bioresour Technol. 2009;100:1214-1220.
Hahn-Hagerdal B. Bio-ethanol: The fuel of tomorrow from the residues of today. Trends Biotechnol. 2006;24:549-556.
Harris EE. Hydrolysis of wood: Treatment with sulfuric acid in a stationary digester. Ind Eng Chem. 2008;37:12-23.
Ioannidou O, Zabaniotou A, Antonakou EV, et al. Investigating the potential for energy, fuel, materials and chemicals production from corn residues by non-catalytic and catalytic pyrolysis. Renew Sustain Energy Rev. 2009;13:750–762.
Jun C, Huibo S, Junhu Z, Wenlu S, Kefa C. Microwave-assisted alkali pretreatment of rice straw to promote enzymatic hydrolysis and hydrogen production in dark- and photo-fermentation. Int J Hydrogen Energy. 2011;36:2093.
Junior MM, Batistote M, Cilli EM, Ernandes JR. Sucrose fermentation by Brazilian ethanol production yeast in media containing structurally complex nitrogen sources. J Inst Brew. 2009;115:191-197.
Khanal SK, Montalbo M, Hans J, et al. Ultrasound enhanced glucose release from corn in ethanol plants. Biotechnol Bioeng. 2007;98:978–985.
Kim TH, Lee YY. Pretreatment of corn stover by soaking in aqueous ammonia. Appl Biochem Biotechnol. 2005;124:1119-1131.
Kirk O. Encyclopedia of Chemical Technology. Vol 2. New York, NY: Wiley; 2001:393-396.
Kjell A. Oil: A bumpy road ahead. World Watch. 2006;19:10.
Kludze H, Deen B, Weersink A, van A R, De Laporte A. Assessment of the availability of agricultural biomass for heat and energy production in Ontario. Available at: http://www.uoguelph.ca/plant/research/agronomy/publications/pdf/Ontario_Biomass_Availability_Project_Final_Report_pdf. Accessed April 23, 2018.
Kokpe M, Christophe M, Fung ML, et al. Production by acetogenic bacteria, an alternative route to chemical synthesis using industrial waste gas. J Appl Environ Microbiol. 2011;77(15):5467-5475.
Krassig H, Schurz J. Ullmann’s Encyclopedia of Industrial Chemistry. 6th ed. Weinheim, Germany: Wiley-VCH; 2002.
Kuhad RC, Gupta R, Khasa YP, Singh A. Bio-ethanol production from Lantana camara (red sage): Pre-treatment, saccharification and fermentation. Bioresour Technol. 2010;101:8348-8354.
Kumar R, Wyman CE. Does change in accessibility with conversion depend on both the substrate and pre-treatment technology? Bioresour Technol. 2009;100:4193-4202.
Licht FO. World Ethanol Market: The Outlook to 2015. Tunbridge Wells, UK: Agra Europe Special Report; 2006.
Lin Y, Tanaka S. Ethanol fermentation from biomass resources: Current state and prospects. Appl Microbiol Biotechnol. 2006;69:627-642.
Marcotullio G, De-jong W. Chloride ions enhance furfural formation from D-xylose in dilute aqueous acidic solution. Green Chem. 2010;12:1739-1746.
Martín C, Galbe M, Wahlbom CF, Hahn-Hägerdal B, Jönsson LJ. Ethanol production from enzymatic hydrolyzates of sugarcane bagasse using recombinant xylose-utilizing Saccharomyces cerevisiae. Enzyme Microb Technol. 2002;31:274–282.
Martin MA. First generation biofuels compete. New Biotechnol. 2010;27(5):596–608.
Maye JP. Use of hop acids in fuel ethanol production. US patent. 2006;26:34-84.
Maziar SA. A study on some efficient parameters in batch fermentation of ethanol using Saccharomyces cerevisiae SC1 extracted from fermented Siahe Sardasht Pomace. Afr J Biotechnol. 2010;9:2906-2912.
Mosier N, Dale B, Elander R, Holtzapple Y, Ladisch M. Features of promising technologies for pretreatment of lignocellulose biomass. Bioresour Technol. 2005;96:673–686.
Motha RP. Development of an agricultural weather policy. Agric For Meteorol. 2007;142:303.
Nikolic S, Mojovic L, Pejin D, Rakin M, Vucurovic V. Improvement of ethanol fermentation of corn semolina hydrolyzates with immobilized yeast by medium supplementation. Food Technol Biotechnol. 2009;47:83-89.
Nitayavardhana S, Rakshit SK, Grewell D, Hans J, Leeuwen V, Khanal SK. Ultrasound pretreatment of cassava chip slurry to enhance sugar release for subsequent ethanol production. Biotechnol Bioeng. 2008;101:487–496.
42. Nitayavardhana S, Leeuwen V, Hans J. Ultrasound improved ethanol fermentation from cassava chips in cassava-based ethanol plants. Bioresour Technol. 2010;101:27-41.
OECD/IEA. From 1st to 2nd Generation Biofuel Technologies: An Overview of Current Industry Activities. Extended Executive Summary. International Energy Agency; 2008. Available at: http://www.iea.org/papers/2008/2nd_Biofuel_Gen_Exec_Sum.pdf. Accessed April 24, 2018.
Onuki S, Koziel JA, Van-leeuwen J, et al. Ethanol production, purification and analysis techniques: A review. ASABE Annu Int Meet. 2008; Providence, Rhode Island.
Phan DH, Yokoyama T, Matsumoto Y. Participation of counter anion in acid hydrolysis of glycoside. In: 16th International Symposium on Wood, Fiber and Pulping Chemistry (ISWFPC). Tianjin, China; 2011:490-493.
Prasad S. Ethanol as an alternative fuel from agricultural, industrial and urban residues. Resour Conserv Recycl. 2007;50:1-39.
Ratnam BV, Ayyanna C. Optimization of medium constituents and fermentation conditions for the production of ethanol from Palmyra jiggery using response surface methodology. World J Microbiol Biotechnol. 2005;21:399-404.
Roehr M. The Biotechnology of Ethanol: Classical and Future Applications. Weinheim, Germany: Wiley-VCH; 2001.
49. Sabrina S, David M, Heather L. Life cycle evaluation of emerging lignocellulose ethanol conversion technologies. Bioresour Technol. 2009;101:654.
Saha BC, Cotta MA. Enzymatic hydrolysis and fermentation of lime pre-treated wheat straw to ethanol. J Chem Technol Biotechnol. 2007;82:913-919.
Salve RV, Hashmi IS, Chilkawar PM. Studies on effect of different hydrolysis method and particle sizes of corncob on bio-ethanol production. Int J Agron Res. 2010;12:391–396.
Sendich E, Laser M, Kim S, et al. Recent process improvements for the ammonia fiber expansion (AFEX) process and resulting reductions in minimum ethanol selling price. Bioresour Technol. 2008;99:8429–8435.
Shi GY, Zhang KC, Tao F, Miao JY. Ethanol fermentation by an acid-tolerant Zymomonas mobilis under non-sterilized condition. Process Biochem. 2009;40:183-187.
Sun Y, Cheng J. Hydrolysis of lignocellulose materials for ethanol production: A review. Bioresour Technol. 2002;83:1–11.
Taherzadeh MJ, Karimi K. Acid-based hydrolysis processes for ethanol from lignocellulose materials: A review. Bioresour Technol. 2007;2:472-499.
Taherzadeh MJ, Karimi K. Pre-treatment of lignocellulose wastes to improve ethanol and biogas production: A review. Int J Mol Sci. 2008;9:1621-1651.
Torres P, Aliakbarian B, Rivas B, Domínguez JM, Converti A. Release of ferulic acid from corn cobs by alkaline hydrolysis. Biochem Eng J. 2008. In Press.
Tu MB, Zhang X, Paice M, McFarlane P, Saddler JN. Effect of surfactants on separate hydrolysis fermentation and simultaneous saccharification fermentation of pretreated lodgepole pine. Biotechnol Prog. 2009;25:1122-1129.
Wyman CE, White PJ, Johnson LA. Applications of corn stover and fiber. In: Corn: Chemistry and Technology. Vol 7. 2003:23-50.
Xu J, Cheng JJ, Sharma-Shivappa RR, Burns JC. Sodium hydroxide pretreatment of switchgrass for ethanol production. Energy Fuels. 2010;24:2113-2119.
Yang B. Pre-treatment: The key to unlocking low-cost cellulosic ethanol. Biofuels Bioprod Biorefin. 2008;2:26.
Yamashita Y, Sasaki C, Nakamura Y. Effective enzyme saccharification and ethanol production from Japanese cedar using various pre-treatment methods. J Biosci Bioeng. 2010;110:79-86.
Zahoor T, Ur-Rehman S, Mushtaq Z, Jamil A, Murtaza MA. Xylitol: A review on bioproduction, application, health benefits, and related safety issues. Crit Rev Food Sci Nutr. 2015;55(11):1514–1528.
Zhang MJ, Wang F, Su RX, Qi W, He ZM. Ethanol production from high dry matter corncob using fed-batch simultaneous saccharification and fermentation after combined pre-treatment. Bioresour Technol. 2010;101:4959–4964.
Zhu S, Wu Y. Production of ethanol from microwave-assisted alkali pre-treated wheat straw. Process Biochem. 2008;41:869-873.
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