Fungal Pretreatment of Corn Stover by Fomes sp. EUM1: Simultaneous Production of Readily Hydrolysable Biomass and Useful Biocatalysts
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In this work we studied two approaches for the revalorization of corn stover (CS): Feedstock for bioethanol generation and substrate for the production of biocatalysts. The practical application of two of these biocatalysts (laccases and cellulases) was also evaluated.
The hydrolysis of CS was improved through a pretreatment with the thermotolerant fungus Fomes sp. EUM1; simultaneously, enzymatic extracts enriched with laccases or cellulases were obtained and applied for the pretreatment or hydrolysis of untreated CS.
After 7 days, the fungal pretreatment promoted a significant increase in the release of reducing sugars (60%) and in the hydrolysis rate (50%). Lignin content decreased 61.2%, while holocellulose remained practically unchanged; a significant positive correlation (r = 0.948, p = 0.01) was found between laccase production and lignin degradation. Regarding biocatalysts application, the cellulases of Fomes sp. EUM1 showed catalytic properties similar to those of commercial enzymes; in addition, the pretreatment with laccases reduced 70% the processing-time (compared to the fungal treatment), and improved the release of reducing sugars and the hydrolysis rate by 26 and 29%, respectively.
The pretreatment of CS with Fomes sp. EUM1 produces two valuable products: saccharificable biomass useful for bioethanol production and highly active enzymes applicable in bioconversion processes.
KeywordsCorn stover Biological pretreatments Bioethanol Enzymatic hydrolysis Lignocellulolytic enzymes White-rot fungi
This work was funded by the Tecnológico Nacional de México (DGO-PYR-2015-072). Méndez-Hernández JE (Reg. No. 268164) thanks Mexican Nacional Council for Science and Technology (CONACyT) for the scholarship. The authors declare that they have no conflicts of interest.
- 1.BP Statistical Review of World Energy June 2017. (2017)Google Scholar
- 3.Renewable Fuel Association. Going Global: 2015 Ethanol Industry Outlook. Renewable Fuel Association, Washington, DC (2015)Google Scholar
- 6.USDA-NASS.: Agricultural statistics data base. National statistics for corn, https://www.nass.usda.gov/Statistics_by_Subject/index.php?sector=CROPS (2016). Accessed 29 Nov 2016
- 7.Instituto Nacional de Estadística y Geografía (INEGI): El sector alimentario en México 2014, Serie estadísticas sectoriales. Instituto Nacional de Estadística y Geografía (INEGI), México (2014)Google Scholar
- 9.Perlack, R.D., Wright, L.L., Turhollow, A.F., Graham, R.L., Stokes, B.J., Erbach, D.C.: Biomass as feedstock for a bioenergy and bioproducts industry: the technical feasibility of a billion-ton annual supply. Department of Energy/GO-102005-2135. U.S. (2005)Google Scholar
- 17.Wolfenden, B.S., Willson, R.L.: Radical-cations as reference chromogens in kinetic studies of ono-electron transfer reactions: pulse radiolysis studies of 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate)., J. Chem. Soc. Perkin Trans. 2. 0, 805–812 (1982)Google Scholar
- 18.Archibald, F.S.: A new assay for lignin-type peroxidases employing the dye azure B. Appl. Environ. Microbiol. 58, 3110–3116 (1992)Google Scholar
- 20.Shin, K., Oh, I., Kim, C.: Production and purification of Remazol Brilliant Blue R decolorizing peroxidase from the culture filtrate of Pleurotus ostreatus. Appl. Environ. Microbiol. 63, 1744–1748 (1997)Google Scholar
- 23.Arce-Cervantes, O., Mendoza, G., Miranda, L., Meneses, M., Loera, O.: Efficiency of lignocellulolytic extracts from thermotolerant strain Fomes sp. EUM1: stability and digestibility of agricultural wastes. J. Agric. Sci. Technol. 15, 229–240 (2013)Google Scholar
- 25.Miller, G.L.: Use of dinitrosalicylic acid reagent for determination of reducing sugar. Anal. Chem. 31, 426–428 (1959)Google Scholar
- 32.Cianchetta, S., Di Maggio, B., Burzi, P.L., Galletti, S.: Evaluation of selected white-rot fungal isolates for improving the sugar yield from wheat stuntreated. Appl. Biochem. Biotechnol. 173, 609–623 (2014)Google Scholar
- 35.Ordaz-Hernández, A., Ortega-Sánchez, E., Montesinos-Matías, R., Hernández-Martínez, R., Torres-Martínez, D., Loera, O.: Morphological and enzymatic response of the thermotolerant fungus Fomes sp. EUM1 in solid state fermentation under thermal stress. FEMS Microbiol. Lett. 363, 1–6 (2016)CrossRefGoogle Scholar