Abstract
Sweet sorghum bagasse displays many characteristics rendering it a promising substrate for lignocellulosic ethanol production. In this study, the steam pretreatment catalyst, enzymatic hydrolysis and the substrate loading for the fermentation were investigated in order to maximise the production of ethanol from the feedstock. The results deemed water as a sufficient pretreatment catalyst since the SO2 impregnation of the biomass did not produce any significant beneficial effects on the yield of ethanol produced. The preferred pretreatment and enzymatic hydrolysis conditions were incorporated in a fed-batch simultaneous saccharification and fermentation (SSF) process using pressed-only (not washed) WIS at a final solid loading of 13% (w/w) that resulted in the targeted ethanol concentration of 39 g/L with a corresponding yield of 82% of the theoretical maximum. Yeast inhibition coupled with significant glucose accumulation was observed at higher solid loadings of 16% and 20%. Ultimately, the sweet sorghum bagasse could be integrated into existing ethanol production regimes to improve the global bioenergy production.
Similar content being viewed by others
Data Availability
All data is reported in the manuscript.
References
Ahorsu R, Medina F, Constantí M (2018) Significance and challenges of biomass as a suitable feedstock for bioenergy and biochemical production : a review. Energies 11:1–19. https://doi.org/10.3390/en11123366
Masnadi MS, El-Houjeiri HM, Schunack D et al (2018) Global carbon intensity of crude oil production. Science 80(361):851–853. https://doi.org/10.1126/science.aar6859
Sims R, Taylor M, Saddler J, Mabee W (2008) From 1st- to 2nd-generation biofuel technologies: An overview of current industry and RD&D activities. International Energy Agency, Paris
Kumari D, Singh R (2018) Pretreatment of lignocellulosic wastes for biofuel production : a critical review. Renew Sustain Energy Rev 90:877–891. https://doi.org/10.1016/j.rser.2018.03.111
Scarlat N, Dallemand JF, Fahl F (2018) Biogas: developments and perspectives in Europe. Renew Energy 129:457–472. https://doi.org/10.1016/j.renene.2018.03.006
Brooks KP, Snowden-Swan LJ, Jones SB et al (2016) Low-carbon aviation fuel through the alcohol to jet pathway. Biofuels for Aviation. Elsevier Inc., Amsterdam, pp 109–150
Geleynse S, Brandt K, Garcia-Perez M et al (2018) The alcohol-to-jet conversion pathway for drop-in biofuels: techno-economic evaluation. Chemsuschem 11:3728–3741. https://doi.org/10.1002/cssc.201801690
Engelberth AS, Clayton Wheeler M, Peter van Walsum G (2018) Techno-economic comparison of three scenarios for upgrading a hemicellulose-rich pre-pulping extract to mixed-alcohols. Biofuels, Bioprod Biorefining 12:1082–1094. https://doi.org/10.1002/bbb.1928
Joelsson E, Erdei B, Galbe M, Wallberg O (2016) Techno-economic evaluation of integrated first- and second-generation ethanol production from grain and straw. Biotechnol Biofuels 9:1–16. https://doi.org/10.1186/s13068-015-0423-8
Almodares A, Hadi MR (2009) Production of bioethanol from sweet sorghum: a review. African J Agric Res 4:772–780
Yu J, Zhong J, Zhang X, Tan T (2010) Ethanol production from H2SO3-steam-pretreated fresh sweet sorghum stem by simultaneous saccharification and fermentation. Appl Biochem Biotechnol 160:401–409. https://doi.org/10.1007/s12010-008-8333-x
Dar RA, Dar EA, Kaur A, Phutela UG (2018) Sweet sorghum-a promising alternative feedstock for biofuel production. Renew Sustain Energy Rev 82:4070–4090. https://doi.org/10.1016/j.rser.2017.10.066
Mathur S, Umakanth AV, Tonapi VA et al (2017) Sweet sorghum as biofuel feedstock: recent advances and available resources. Biotechnol Biofuels 10:1–19. https://doi.org/10.1186/s13068-017-0834-9
Ekefre DE, Mahapatra AK, Latimore M et al (2017) Evaluation of three cultivars of sweet sorghum as feedstocks for ethanol production in the Southeast United States. Heliyon 3:e00490. https://doi.org/10.1016/j.heliyon.2017.e00490
Mundia CW, Secchi S, Akamani K, Wang G (2019) A regional comparison of factors affecting global sorghum production : the case of North America, Asia and Africa’s Sahel. Sustainability 11:1–18. https://doi.org/10.3390/su11072135
Kim I, Han JI (2012) Optimization of alkaline pretreatment conditions for enhancing glucose yield of rice straw by response surface methodology. Biomass Bioenerg 46:210–217. https://doi.org/10.1016/j.biombioe.2012.08.024
Wang L, Luo Z, Shahbazi A (2013) Optimization of simultaneous saccharification and fermentation for the production of ethanol from sweet sorghum (Sorghum bicolor) bagasse using response surface methodology. Ind Crop Prod 42:280–291. https://doi.org/10.1016/j.indcrop.2012.06.005
Ballesteros M, Oliva JM, Negro MJ et al (2004) Ethanol from lignocellulosic materials by a simultaneous saccharification and fermentation process (SFS) with Kluyveromyces marxianus CECT 10875. Process Biochem 39:1843–1848. https://doi.org/10.1016/j.procbio.2003.09.011
Matsakas L, Christakopoulos P (2013) Fermentation of liquefacted hydrothermally pretreated sweet sorghum bagasse to ethanol at high-solids content. Bioresour Technol 127:202–208. https://doi.org/10.1016/j.biortech.2012.09.107
Zhang C, Wen H, Chen C et al (2019) Simultaneous saccharification and juice co-fermentation for high-titer ethanol production using sweet sorghum stalk. Renew Energy 134:44–53. https://doi.org/10.1016/j.renene.2018.11.005
Rohowsky B, Häßler T, Gladis A et al (2013) Feasibility of simultaneous saccharification and juice co-fermentation on hydrothermal pretreated sweet sorghum bagasse for ethanol production. Appl Energy 102:211–219. https://doi.org/10.1016/j.apenergy.2012.03.039
Umagiliyage AL, Choudhary R, Liang Y et al (2015) Laboratory scale optimization of alkali pretreatment for improving enzymatic hydrolysis of sweet sorghum bagasse. Ind Crops Prod 74:977–986. https://doi.org/10.1016/j.indcrop.2015.05.044
Yu M, Li J, Chang S et al (2016) Bioethanol production using the sodium hydroxide pretreated sweet sorghum bagasse without washing. Fuel 175:20–25. https://doi.org/10.1016/j.fuel.2016.02.012
del Río PG, Gomes-Dias JS, Rocha CMR et al (2020) Recent trends on seaweed fractionation for liquid biofuels production. Bioresour Technol 299:1–15. https://doi.org/10.1016/j.biortech.2019.122613
Yang J, Kim JE, Kim JK et al (2017) Evaluation of commercial cellulase preparations for the efficient hydrolysis of hydrothermally pretreated empty fruit bunches. BioResources 12:7834–7840
Baruah J, Nath BK, Sharma R et al (2018) Recent trends in the pretreatment of lignocellulosic biomass for value-added products. Front Energy Res 6:1–19. https://doi.org/10.3389/fenrg.2018.00141
Oliva JM, Negro MJ, Manzanares P et al (2017) A sequential steam explosion and reactive extrusion pretreatment for lignocellulosic biomass conversion within a fermentation-based biorefinery perspective. Fermentation 3:1–15. https://doi.org/10.3390/fermentation3020015
Ruiz HA, Conrad M, Sun SN et al (2020) Engineering aspects of hydrothermal pretreatment: from batch to continuous operation, scale-up and pilot reactor under biorefinery concept. Bioresour Technol 299:122685. https://doi.org/10.1016/j.biortech.2019.122685
Pengilly C, García-Aparicio MP, Diedericks D et al (2015) Enzymatic hydrolysis of steam-pretreated sweet sorghum bagasse by combinations of cellulase and endo-xylanase. Fuel 154:352–360. https://doi.org/10.1016/j.fuel.2015.03.072
Cara C, Moya M, Ballesteros I et al (2007) Influence of solid loading on enzymatic hydrolysis of steam exploded or liquid hot water pretreated olive tree biomass. Process Biochem 42:1003–1009. https://doi.org/10.1016/j.procbio.2007.03.012
Klein-marcuschamer D, Oleskowicz-popiel P, Simmons BA, Blanch HW (2012) The challenge of enzyme cost in the production of lignocellulosic biofuels. Biotechnol Bioeng 109:1083–1087
McIntosh S, Vancov T (2011) Optimisation of dilute alkaline pretreatment for enzymatic saccharification of wheat straw. Biomass Bioenerg 35:3094–3103. https://doi.org/10.1016/j.biombioe.2011.04.018
Mcintosh PA (2013) Selection of preferred sweet sorghum cultivars and their pretreatment optimisation for bio-ethanol production. MSc Thesis, Stellenbosch University
Öhgren K, Rudolf A, Galbe M, Zacchi G (2006) Fuel ethanol production from steam-pretreated corn stover using SSF at higher dry matter content. Biomass Bioenerg 30:863–869. https://doi.org/10.1016/j.biombioe.2006.02.002
Sipos B, Réczey J, Somorai Z et al (2009) Sweet sorghum as feedstock for ethanol production: enzymatic hydrolysis of steam-pretreated bagasse. Appl Biochem Biotechnol 153:151–162. https://doi.org/10.1007/s12010-008-8423-9
Sluiter A, Ruiz A, Scarlata C, Sluiter J, Templeton D (2008) Determination of extractives in biomass: laboratory analytical procedure (LAP), NREL/TP-510-42619
Sluiter A, Hames B, Ruiz R et al (2008) Determination of ash in biomass: laboratory analytical procedure (LAP), NREL/TP-510-42622
Sluiter A, Hames B, Ruiz R et al (2008) Determination of structural carbohydrates and lignin in Biomass: laboratory analytical procedure (LAP), NREL/TP-510-42618
Resch M, Baker J, Decker S (2015) Low solids enzymatic saccharification of lignocellulosic biomass. Laboratory Analytical Procedure/Technical Report NREL/TP-5100–63351. Prepared for National Renewable Energy Laboratory, Golden, CO
Ghose TK (1987) Measurement of cellulase activities. Pure Appl Chem 59:257–268. https://doi.org/10.1111/j.1468-2389.1995.tb00038.x
Bailey MJ, Biely P, Poutanen K (1992) Interlaboratory testing of methods for assay of xylanase activity. J Biotechnol 23:257–270. https://doi.org/10.1016/0168-1656(92)90074-J
Hu Y, Zhu Z, Nielsen J, Siewers V (2018) Heterologous transporter expression for improved fatty alcohol secretion in yeast. Metab Eng 45:51–58. https://doi.org/10.1016/j.ymben.2017.11.008
Manzanares P, Ballesteros I, Negro MJ et al (2012) Biological conversion of forage sorghum biomass to ethanol by steam explosion pretreatment and simultaneous hydrolysis and fermentation at high solid content. Biomass Convers Biorefinery 2:123–132. https://doi.org/10.1007/s13399-012-0040-8
Shen F, Hu J, Zhong Y et al (2012) Ethanol production from steam-pretreated sweet sorghum bagasse with high substrate consistency enzymatic hydrolysis. Biomass Bioenerg 41:157–164. https://doi.org/10.1016/j.biombioe.2012.02.022
Olofsson K, Bertilsson M, Lidén G (2008) A short review on SSF - an interesting process option for ethanol production from lignocellulosic feedstocks. Biotechnol Biofuels 1:1–14. https://doi.org/10.1186/1754-6834-1-7
Tengborg C, Galbe M, Zacchi G (2001) Reduced inhibition of enzymatic hydrolysis of steam-pretreated softwood. Enzyme Microb Technol 28:835–844. https://doi.org/10.1016/S0141-0229(01)00342-8
Kahar P, Ida E, Otsuka H et al (2017) Challenges of non-flocculating Saccharomyces cerevisiae haploid strain against inhibitory chemical complex for ethanol production. Bioresour Technol 245:1436–1446. https://doi.org/10.1016/j.biortech.2017.06.009
Wang S, Sun X, Yuan Q (2018) Strategies for enhancing microbial tolerance to inhibitors for biofuel production: a review. Bioresour Technol 258:302–309. https://doi.org/10.1016/j.biortech.2018.03.064
Keating JD, Panganiban C, Mansfiel SD (2006) Tolerance and adaptation of ethanologenic yeasts to lignocellulosic inhibitory compounds. Biotechnol Bioeng 93:1196–1206. https://doi.org/10.1002/bit
Mithra MG, Jeeva ML, Sajeev MS, Padmaja G (2018) Comparison of ethanol yield from pretreated lignocellulo- starch biomass under fed-batch SHF or SSF modes. Heliyon 4(10):1–31. https://doi.org/10.1016/j.heliyon.2018.e00885
Pazitny A, Russ A, Bohacek S, Stankovska M (2020) Effect of steam explosion on enzymatic hydrolysis of various parts of poplar tree. Wood Res 65:579–590
Mishra A, Ghosh S (2017) A perspective on current technologies used for bioethanol production from lignocellulosics. In: Advances in biofeedstocks and biofuels: production technologies for biofuels, II. Scrivener Publishing LLC, pp 25–66
Ding MZ, Wang X, Yang Y, Yuan YJ (2011) Metabolomic study of interactive effects of phenol, furfural, and acetic acid on Saccharomyces cerevisiae. Omi A J Integr Biol 15:647–653. https://doi.org/10.1089/omi.2011.0003
Graves T, Narendranath NV, Dawson K, Power R (2006) Effect of pH and lactic or acetic acid on ethanol productivity by Saccharomyces cerevisiae in corn mash. J Ind Microbiol Biotechnol 33:469–474. https://doi.org/10.1007/s10295-006-0091-6
Graves T, Narendranath NV, Dawson K, Power R (2007) Interaction effects of lactic acid and acetic acid at different temperatures on ethanol production by Saccharomyces cerevisiae in corn mash. Appl Microbiol Biotechnol 73:1190–1196. https://doi.org/10.1007/s00253-006-0573-5
Jung YH, Kim KH (2017) Evaluation of the main inhibitors from lignocellulose pretreatment for enzymatic hydrolysis and yeast fermentation. BioResources 12:9348–9356
Balderas VE, Kevin H, Radhakrishnan C (2018) Inactivation of the transcription factor mig1 ( YGL035C ) in Saccharomyces cerevisiae improves tolerance towards monocarboxylic weak acids : acetic, formic and levulinic acid. J Ind Microbiol Biotechnol 45:735–751. https://doi.org/10.1007/s10295-018-2053-1
Dziekońska-Kubczak U, Patelski P, Balcerek M et al (2015) Effect of acetic acid concentration on ethanol productivity by Saccharomyces Cerevisiae. CER Comparative European Research 2015:156–158
Palmqvist E, Hahn-Hägerdal B (2000) Fermentation of lignocellulosic hydrolysates. II: Inhibitors and mechanisms of inhibition. Bioresour Technol 74:25–33. https://doi.org/10.1016/S0960-8524(99)00161-3
Madhavan A, Tamalampudi S, Srivastava A et al (2009) Alcoholic fermentation of xylose and mixed sugars using recombinant Saccharomyces cerevisiae engineered for xylose utilization. Appl Microbiol Biotechnol 82:1037–1047. https://doi.org/10.1007/s00253-008-1818-2
Moreno AD, Tomás-Pejó E, Ibarra D et al (2013) Fed-batch SSCF using steam-exploded wheat straw at high dry matter consistencies and a xylose-fermenting Saccharomyces cerevisiae strain : effect of laccase supplementation. Biotechnol Biofuels 6:1–10
Vargas F, Domínguez E, Vila C et al (2015) Agricultural residue valorization using a hydrothermal process for second generation bioethanol and oligosaccharides production. Bioresour Technol 191:263–270. https://doi.org/10.1016/j.biortech.2015.05.035
Fernandes MC, Ferro MD, Paulino AFC et al (2015) Enzymatic saccharification and bioethanol production from Cynara cardunculus pretreated by steam explosion. Bioresour Technol 186:309–315. https://doi.org/10.1016/j.biortech.2015.03.037
McIntosh S, Palmer J, Zhang Z et al (2017) Simultaneous saccharification and fermentation of pretreated Eucalyptus grandis under high solids loading. Ind Biotechnol 13:131–140. https://doi.org/10.1089/ind.2016.0018
Kossatz HL, Rose SH, Viljoen-bloom M, Van ZWH (2017) Production of ethanol from steam exploded triticale straw in a simultaneous saccharification and fermentation process. Process Biochem 53:10–16. https://doi.org/10.1016/j.procbio.2016.11.023
Cassells B, Karhumaa K, Sànchez i Nogué V, Lidén G (2017) Hybrid SSF/SHF processing of SO2 pretreated wheat straw—tuning co-fermentation by yeast inoculum size and hydrolysis time. Appl Biochem Biotechnol 181:536–547. https://doi.org/10.1007/s12010-016-2229-y
Funding
This research was supported financially by the Technology Innovation Agency of South Africa.
Author information
Authors and Affiliations
Contributions
All authors contributed to the formulation and conceptualisation of the research, experimental work, interpretation of data, writing and revision of the manuscript. All authors approved the final manuscript.
Corresponding author
Ethics declarations
Ethics Approval
The paper follows ethical standards.
Consent to Participate
All authors from this work consent the participation in this work.
Consent for Publication
The authors authorise the paper publication in BioEnergy Research Journal.
Conflict of Interest
The authors declare no competing interests.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Highlights
• Fed-batch SSF with 13% solid loading resulted in 39 g/L of ethanol.
• Higher solid loadings resulted in inhibitory acetic acid concentrations.
• SO2 impregnation for biomass pretreatment did not benefit ethanol production.
Rights and permissions
About this article
Cite this article
Bedzo, O.K.K., Dreyer, C.B., van Rensburg, E. et al. Optimisation of Pretreatment Catalyst, Enzyme Cocktail and Solid Loading for Improved Ethanol Production from Sweet Sorghum Bagasse . Bioenerg. Res. 15, 1083–1095 (2022). https://doi.org/10.1007/s12155-021-10298-w
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12155-021-10298-w