Biofuel Research Journal

Biofuel Research Journal

Fungal protein and ethanol from lignocelluloses using Rhizopus pellets under simultaneous saccharification, filtration and fermentation (SSFF)

Document Type : Research Paper

Authors
Somayeh FazeliNejad
Jorge A. Ferreira
Tomas Brandberg
Patrik R. Lennartsson
Mohammad J. Taherzadeh
Swedish Centre for Resource Recovery, University of Borås, SE 501 90, Borås, Sweden
10.18331/BRJ2016.3.1.7
Abstract
The economic viability of the 2nd generation bioethanol production process cannot rely on a single product but on a biorefinery built around it. In this work, ethanol and fungal biomass (animal feed) were produced from acid-pretreated wheat straw slurry under an innovative simultaneous saccharification, fermentation, and filtration (SSFF) strategy. A membrane unit separated the solids from the liquid and the latter was converted to biomass or to both biomass and ethanol in the fermentation reactor containing Rhizopus sp. pellets. Biomass yields of up to 0.34 g/g based on the consumed monomeric sugars and acetic acid were achieved. A surplus of glucose in the feed resulted in ethanol production and reduced the biomass yield, whereas limiting glucose concentrations resulted in higher consumption of xylose and acetic acid. The specific growth rate, in the range of 0.013-0.015/h, did not appear to be influenced by the composition of the carbon source. Under anaerobic conditions, an ethanol yield of 0.40 g/g was obtained. The present strategy benefits from the easier separation of the biomass from the medium and the fungus ability to assimilate carbon residuals in comparison with when yeast is used. More specifically, it allows in-situ separation of insoluble solids leading to the production of pure fungal biomass as a value-added product.

Graphical Abstract

Fungal protein and ethanol from lignocelluloses using Rhizopus pellets under simultaneous saccharification, filtration and fermentation (SSFF)

Highlights

  • Economically viable production of 2nd generation bioethanol cannot rely on a single product.

  • SSFF can be used for production of ethanol and biomass from wheat straw.

  • Glucose present in the feed controlled the assimilation of xylose and acetic acid.

  • The fungal growth rate was found not to be influenced by the feed composition.

  • Rhizopus biomass yields of up 0.34 g/g and ethanol yields of 0.40 g/g were obtained.

Keywords
Cellulosic ethanol
Animal feed
Rhizopus sp
SSFF
Wheat straw
[1] Adney, B., Baker, J., 2008. Measurement of cellulase activities. National Renewable Energy Laboratory.
[2] Baboukani, B. S., Vossoughi, M., Alemzadeh, I., 2012. Optimisation of dilute-acid pretreatment conditions for enhancement sugar recovery and enzymatic hydrolysis of wheat straw. Biosys. Eng. 111, 166-174.
[3] Balat, M., 2011. Production of bioethanol from lignocellulosic materials via the biochemical pathway: a review. Energy Convers. Manage. 52, 858-875.
[4] Canilha, L., Carvalho, W., Batista, J., Silva, A. e., 2006. Xylitol bioproduction from wheat straw: hemicellulose hydrolysis and hydrolyzate fermentation. J. Sci. Food Agr. 86, 1371-1376.
[5] Cherubini, F., 2010. The biorefinery concept: Using biomass instead of oil for producing energy and chemicals. Energy Convers. Manage. 51, 1412-1421.
[6] FazeliNejad, S., Brandberg, T., Lennartsson, P. R., Taherzadeh, M. J., 2013. Inhibitor Tolerance: A Comparison between Rhizopus sp. and Saccharomyces cerevisiae. Bioresources. 8, 5524-5535.
[7] Ferreira, J.A., Lennartsson, P.R., Edebo, L., Taherzadeh, M.J., 2013. Zygomycetes-based biorefinery: Present status and future prospects. Bioresour. Technol. 135, 523-532.
[8] Gnansounou, E., Dauriat, A., 2010. Techno-economic analysis of lignocellulosic ethanol: a review. Bioresour. Technol. 101, 4980-4991.
[9] Ishola, M.M., 2014. Novel application of membrane bioreactors in lignocellulosic ethanol production, PhD, University of Borås, Borås, Sweden.
[10] Ishola, M.M., Jahandideh, A., Haidarian, B., Brandberg, T., Taherzadeh, M.J., 2013. Simultaneous saccharification, filtration and fermentation (SSFF): A novel method for bioethanol production from lignocellulosic biomass. Bioresour. Technol. 133, 68-73.
[11] Kim, Y., Mosier, N. S., Hendrickson, R., Ezeji, T., Blaschek, H., Dien, B., Cotta, M., Dale, B., Ladisch, M.R., 2008. Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage. Bioresour. Technol. 99, 5165-5176.
[12] Lennartsson, P.R., Karimi, K., Edebo, L., Taherzadeh, M.J., 2009. Effects of different growth forms of Mucor indicus on cultivation on dilute-acid lignocellulosic hydrolyzate, inhibitor tolerance, and cell wall composition. J. Biotechnol. 143, 255-261.
[13] Leonard, R.H., Hajny, G.J., 1945. Fermentation of wood sugars to ethyl alcohol. Ind. Eng. Chem. 37, 390-395.
[14] Metz, B., Kossen, N.W.F., 1977. The growth of molds in the form of pellets - a literature review. Biotechnol. Bioeng. 19, 781-799.
[15] Millati, R., Edebo, L., Taherzadeh, M.J., 2005. Performance of Rhizopus, Rhizomucor, and Mucor in ethanol production from glucose, xylose, and wood hydrolyzates. Enzyme Microb. Technol. 36, 294-300.
[16] Nyman, J., Lacintra, M.G., Westman, J.O., Berglin, M., Lundin, M., Lennartsson, P.R., Taherzadeh, M.J., 2013. Pellet formation of zygomycetes and immobilization of yeast. New Biotechnol. 30, 516-522.
[17] 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.
[18] Pandey, A., Höfer, R., Larroche, C., Taherzadeh, M.J., Nampoothiri, M., 2015. Industrial Biorefineries and White Biotechnology. Elsevier.
[19] Peng, F., Peng, P., Xu, F., Sun, R.C., 2012. Fractional purification and bioconversion of hemicelluloses. Biotechnol. Adv. 30, 879-903.
[20] RFA, 2014. Ethanol industry outlook. Renewable Fuels Association.
[21] Skinner, K., Leathers, T., 2004. Bacterial contaminants of fuel ethanol production. J. Ind. Microbiol. Biot. 31, 401-408.
[22] Sluiter, A., Hames, B., Ruiz, R., Scarlata, C., Sluiter, J., Templeton, D., Crocker, D., 2011. Determination of structural carbohydrates and lignin in biomass. National Renewable Energy Laboratory, Colorado, USA.
[23] Talebnia, F., Karakashev, D., Angelidaki, I., 2010. Production of bioethanol from wheat straw: an overview on pretreatment, hydrolysis and fermentation. Bioresour. Technol. 101, 4744-4753.
[24] Wheals, A.E., Basso, L.C., Alves, D.M.G., Amorim, H.V., 1999. Fuel ethanol after 25 years. Trends Biotechnol. 17, 482-487.
[25] Wikandari, R., Millati, R., Lennartsson, P., Harmayani, E., Taherzadeh, M., 2012. Isolation and characterization of Zygomycetes fungi from tempe for ethanol production and biomass applications. Appl. Biochem. Biotechnol. 167, 1501-1512.
[26] Wingren, A., Galbe, M., Zacchi, G., 2003. Techno-economic evaluation of producing ethanol from softwood: Comparison of SSF and SHF and identification of bottlenecks. Biotechnol. Progr. 19, 1109-1117.
Biofuel Research Journal
Volume 3, Issue 1 - Serial Number 1
Winter 2016
Pages 372-378