title: Microplate-Based Evaluation of the Sugar Yield from Giant Reed, Giant Miscanthus and Switchgrass after Mild Chemical Pre-Treatments and Hydrolysis with Tailored Trichoderma Enzymatic Blends.
abstract: Giant reed, miscanthus, and switchgrass are considered prominent lignocellulosic feedstocks to obtain fermentable sugars for biofuel production. The bioconversion into sugars requires a delignifying pre-treatment step followed by hydrolysis with cellulase and other accessory enzymes like xylanase, especially in the case of alkali pre-treatments, which retain the hemicellulose fraction. Blends richer in accessory enzymes than commercial mix can be obtained growing fungi on feedstock-based substrates, thus ten selected Trichoderma isolates, including the hypercellulolytic strain Trichoderma reesei Rut-C30, were grown on giant reed, miscanthus, or switchgrass-based substrates. The produced enzymes were used to saccharify the corresponding feedstocks, compared to a commercial enzymatic mix (6 FPU/g). Feedstocks were acid (H2SO40.2-2%, w/v) or alkali (NaOH 0.02-0.2%, w/v) pre-treated. A microplate-based approach was chosen for most of the experimental steps due to the large number of samples. The highest bioconversion was generally obtained with Trichoderma harzianum Or4/99 enzymes (78, 89, and 94% final sugar yields at 48 h for giant reed, miscanthus, and switchgrass, respectively), with significant increases compared to the commercial mix, especially with alkaline pre-treatments. The differences in bioconversion yields were only partially caused by xylanases (maximum R2= 0.5), indicating a role for other accessory enzymes.
authors.affiliation: Council for Agricultural Research and Economics, Research Center for Agriculture and Environment (CREA-AA), Via di Corticella 133, 40128, Bologna, Italy. stefano.cianchetta@crea.gov.it.
authors.forename: Stefano
authors.identifier: http://orcid.org/0000-0003-0806-460X
authors.initials: S
authors.lastname: Cianchetta
authors.affiliation: Council for Agricultural Research and Economics, Research Center for Agriculture and Environment (CREA-AA), Via di Corticella 133, 40128, Bologna, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Bregoli
authors.affiliation: Council for Agricultural Research and Economics, Research Center for Agriculture and Environment (CREA-AA), Via di Corticella 133, 40128, Bologna, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Galletti
mesh_terms: D001709:Biotechnology / Q000295:instrumentation / Q000379:methods*; D050260:Carbohydrate Metabolism; D002480:Cellulase / Q000378:metabolism*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D006868:Hydrolysis; D008031:Lignin / Q000378:metabolism; D055616:Microtechnology / Q000295:instrumentation / Q000379:methods*; D008897:Panicum / Q000378:metabolism*; D014242:Trichoderma / Q000201:enzymology*
chemical_list: C036909:lignocellulose; D008031:Lignin; D002480:Cellulase; D043364:Endo-1,4-beta Xylanases
keywords: Acid pre-treatment; Alkaline pre-treatment; Arundo donax; Cellulase; Lignocellulose; Miscanthus × giganteus; Panicum virgatum; Reducing sugars; Trichoderma; Xylanase