Liquid hot water pretreatment of multi feedstocks and enzymatic hydrolysis of solids obtained thereof

Agricultural feedstocks (brewer spent grains BSG, corncob CC, corn husk CH, wheat straw WS and Luffa sponge LS) were pretreated by liquid hot water (LHW) in order to increase cellulose recovery and enzymatic saccharification. LHW-pretreatment resulted in hemicellulose solubilization, and solids enriched in cellulose. Chemical analysis showed different susceptibilities of the feedstocks to LHW-pretreatment and enzymatic hydrolysis. Pretreated feedstocks presented higher crystallinity (determined through X-ray diffraction) and thermal stability (determined through thermogravimetric analysis) than untreated feedstocks. SEM images confirmed the effect of LHW-pretreatment on structural changes. Moreover, enzymatic hydrolysis and cellulose conversion to glucose (CCG) were improved for pretreated feedstocks, with exception of LS. CCG (in relation to glucose potential on solids) followed the order: BSG>CH>WS>CC>LS. LHW-pretreatment showed to be a good technology to pretreat multi feedstocks and for improving the enzymatic hydrolysis of recalcitrant agricultural feedstocks to sugars, which can be further converted to ethanol-fuel and other value-added chemicals.Michele Michelin is a recipient of a Portuguese Foundation for Science and Technology (FCT) fellowship (SFRH/BPD/100786/2014). This study was supported by the FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462). The authors would like to thank Novozymes A/S for samples of Cellic Ctec2

Integration of autohydrolysis and organosolv process for recovery of lignin from corncob

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Lignocelluloses, such as hardwood, softwood and agricultural residues, are low cost feedstocks mainly composed by cellulose, hemicellulose and lignin. Lignin is the third most abundant naturally synthesized polymer. It presents an amorphous polyphenolic structure, which can be used for the development of bio-based materials and chemicals. However, the bioconversion of renewable lignocelluloses to valueadded products requires their fractionation through pretreatment technologies [1,2]. [...]info:eu-repo/semantics/publishedVersio

Challenges in using ionic liquids for cellulosic ethanol production

The growing need to expand the use of renewable energy sources in a sustainable manner, providing greater energy supply security and reducing the environmental impacts associated with fossil fuels, finds in the agricultural by-product bioethanol an economically viable alternative with significant expansion potential. In this regard, a dramatic boost in the efficiency of processes already in place is required, reducing costs, industrial waste, and our carbon footprint. Biofuels are one of the most promising alternatives to massively produce energy sustainably in a short-term period. Lignocellulosic biomass (LCB) is highly recalcitrant, and an effective pretreatment strategy should also minimize carbohydrate degradation by diminishing enzyme inhibitors and other products that are toxic to fermenting microorganisms. Ionic liquids (ILs) have been playing an important role in achieving cleaner processes as a result of their excellent physicochemical properties and outstanding performance in the dissolution and fractionation of lignocellulose. This review provides an analysis of recent advances in the production process of biofuels from LCB using ILs as pretreatment and highlighting techniques for optimizing and reducing process costs that should help to develop robust LCB conversion processes.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and CEECIND/03378/2018; by LABBELS—Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020 and H.R. acknowledges Xunta de Galicia for support through project ED431B 2020/021, co-funded by the European Regional Development Fund, and “Agrupación Europea de Cooperación Territorial—Galicia—Norte de Portugal (GNP-AECT)” for support of a visiting stay at the University of Minho via Iacobus program.info:eu-repo/semantics/publishedVersio

Valorization of wastes from agrofood and pulp and paper industries within the biorefinery concept: southwestern Europe scenario

Nowadays, the need to attain a sustainable society increasingly demands for the development of an economy based on biorefineries. In Southwestern Europe, agrofood and forest industries produce significant amount of wastes that could satisfy the demand for renewable biomass to be used in a biorefinery scheme alternatively to traditional uses of these residues. This chapter will primarily cover the current scenario regarding the annual volume of residues generated by agrofood (cheese whey, vine pruning waste, and brewer's spent grains) and pulp and paper industry (sawdust, chips, bark, and sludge). Additionally, the present-day use and final destination of these wastes and their main environmental issues will be described and discussed; besides, advanced valorization strategies (e.g., fuels and chemicals) involving a biorefinery approach will be approached, based on current reports according to the chemical composition of each waste. Finally, new insights on valorization of wastes from agrofood and pulp and paper industries, its challenges, and trends for future research will be presented.(undefined)info:eu-repo/semantics/publishedVersio

Carboxymethyl cellulose/lignin blended films: physicochemical and antioxidant properties

info:eu-repo/semantics/publishedVersio

Exploring the potential of primary sludges from paper mills for the production of value-added compounds

Background & Objectives: Industrial residues are emerging as low-cost alternatives to typical lignocellulosic materials, usually more expensive and hard to process, being currently the center of an urgent transition into a greener economy. One possible example are the primary sludges abundantly produced by paper mills, typically burned for heat generation. This work aimed to assess the potential of primary sludges to enzymatically produce monomer sugars that can be later converted into different compounds. Methods: Pressed sludges from the primary treatment of effluents from a paper mill were provided by RAIZ (Aveiro, Portugal). These were subjected to a chemical treatment to remove a high content of calcium carbonate, allowing to concentrate their cellulosic fraction. This treated material was hydrolyzed using a commercial cocktail of cellulases (Cellic Ctec 2) at 500C under different solids loadings and feeding regimes. The hydrolysis performance was evaluated from the levels of glucose released over time, quantified by HPLC. Results: Initial compositional analysis of the primary sludges determined a rather modest cellulose content, around 30 %. Different neutralization processes were tested to remove the high content of carbonates, the best option allowing to concentrate cellulose fraction to 58 %. The neutralized solid was then tested for its hydrolysis susceptibility. A saccharification efficiency of 92 % was achieved in 140 h of a batch hydrolyses with 9 % solids. When superior solid loadings were employed, specifically 15 and 17.5 %, the saccharification efficiency slightly decreased to 90 and 87 %, respectively, still representing very interesting levels. For the 17.5 % suspension, a maximum of 102 g/L of glucose was obtained, which already represents an attractive level of glucose that can be further converted into a variety of compounds. Using an alternative strategy comprising a batch process (12.5 % solids) combined with multiple pulses of 2 % solid resulted in a slight reduction of the saccharification yield (82 %) but a 35 % reduction on enzymes consumption. Conclusions: Primary sludges from paper mills are an interesting raw-material to produce several added-value compounds, relying on a sugar-rich and easy-to-process material. This can also represent a new and more attractive valorization route for this residue, representing an important economic gain for paper manufacturing sector.This work had the financial support from the Portuguese Foundation for Science and Technology under the scope of Project EcoTech (POCI-01-0145-FEDER-032206). The authors also acknowledge RAIZ for providing the primary sludges.info:eu-repo/semantics/publishedVersio

Multi-step approach to add value to corncob: production of biomass-degrading enzymes, lignin and fermentable sugars

This work presents an integrated and multi-step approach for the recovery and/or application of the lignocellulosic fractions from corncob in the production of high value added compounds as xylo-oligosaccharides, enzymes, fermentable sugars, and lignin in terms of biorefinery concept. For that, liquid hot water followed by enzymatic hydrolysis were used. Liquid hot water was performed using different residence times (1050 minutes) and holding temperature (180200 °C), corresponding to severities (log(R0)) of 3.364.64. The most severe conditions showed higher xylo-oligosaccharides extraction (maximum of 93%) into the hydrolysates and higher recovery of cellulose on pretreated solids (maximum of 65%). Subsequently, hydrolysates and solids were used in the production of xylanases and cellulases, respectively, as well as, pretreated solids were also subjected to enzymatic hydrolysis for the recovery of lignin and fermentable sugars from cellulose. Maximum glucose yield (100%) was achieved for solids pretreated at log(R0) of 4.42 and 5% solid loading.Michele Michelin is a recipient of a FCT fellowship (SFRH/BPD/ 100786/2014). ThisstudywassupportedbythePortugueseFoundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-010145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Héctor Ruiz would like to thank the financial support to the Mexican Science and Technology Council (CONACYT, Mexico) for the Basic Science Project-2015-01 (Ref. 254808) and the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (Cemie-Bio), and Cluster of Bioalcohols (Ref. 249564). We thank Dr. Nelson Lima from MUM (Micoteca da Universidade do Minho, PT) that gently provided the Trichoderma reesei fungi.info:eu-repo/semantics/publishedVersio

Enhancement and modeling of enzymatic hydrolysis on cellulose from Agave bagasse hydrothermally pretreated in a horizontal bioreactor

One of the major challenges in biofuels production from lignocellulosic biomass is the generation of high glucose titers from cellulose in the enzymatic hydrolysis stage of pretreated biomass to guarantee a cost-effective process. Therefore, the enzymatic saccharification on cellulose at high solid loading is an alternative. In this work, the agave bagasse was hydrothermally pretreated and optimized at 194°C/30min, obtaining a pretreated solid rich in cellulose content (>46.46%), and subjected to enzymatic hydrolysis at high solid levels. A horizontal bioreactor was designed for enzyme saccharification at high solid loadings [25% (w/v)]. The bioreactor improved mixing efficiency, with cellulose conversions up to 98% (195.6g/L at 72h). Moreover, mathematical modeling of cellulase deactivation demonstrated that cellulases lose most of their initial activity in the first hours of the reaction. Also, cellulose was characterized by X-ray diffraction, and the pretreated solids were visualized using scanning electron microscopy.This project was funded by the Secretary of Public Education of Mexico - Mexican Science and Technology Council (SEP-CONACYT) with the Basic Science Project-2015-01 (Ref. 254808). Marcela Sofía Pino also thanks the National Council for Science and Technology (CONACYT, Mexico) for her Master Fellowship support (grant number: 611312/452636), and Dr. Michele Michelin thanks the Portuguese Foundation for Science and Technology (FCT) for her postdoctoral fellowship (SFRH/BPD/100786/2014).info:eu-repo/semantics/publishedVersio