@article{fillat_martin-sampedro_gonzalez_ferrer_ibarra_eugenio_2017, title={Biobleaching of orange tree pruning cellulose pulp with xylanase and laccase mediator systems}, volume={51}, number={1-2}, journal={Cellulose Chemistry and Technology}, author={Fillat, U. and Martin-Sampedro, R. and Gonzalez, Z. and Ferrer, A. and Ibarra, D. and Eugenio, M. E.}, year={2017}, pages={55–65} }
 @article{pereira_hoeger_ferrer_rencoret_rio_kruus_rahikainen_kellock_gutierrez_rojas_2017, title={Lignin Films from Spruce, Eucalyptus, and Wheat Straw Studied with Electroacoustic and Optical Sensors: Effect of Composition and Electrostatic Screening on Enzyme Binding}, volume={18}, ISSN={["1526-4602"]}, DOI={10.1021/acs.biomac.7b00071}, abstractNote={Lignins were isolated from spruce, wheat straw, and eucalyptus by using the milled wood lignin (MWL) method. Functional groups and compositional analyses were assessed via 2D NMR and 31P NMR to realize their effect on enzyme binding. Films of the lignins were fabricated and ellipsometry, atomic force microscopy, and water contact angle measurements were used for their characterization and to reveal the changes upon enzyme adsorption. Moreover, lignin thin films were deposited on quartz crystal microgravimetry (QCM) and surface plasmon (SPR) resonance sensors and used to gain further insights into the lignin-cellulase interactions. For this purpose, a commercial multicomponent enzyme system and a monocomponent Trichoderma reesei exoglucanase (CBH-I) were considered. Strong enzyme adsorption was observed on the various lignins but compared to the multicomponent cellulases, CBH-I displayed lower surface affinity and higher binding reversibility. This resolved prevalent questions related to the affinity of this enzyme with lignin. Remarkably, a strong correlation between enzyme binding and the syringyl/guaiacyl (S/G) ratio was found for the lignins, which presented a similar hydroxyl group content (31P NMR): higher protein affinity was determined on isolated spruce lignin (99% G units), while the lowest adsorption occurred on isolated eucalyptus lignin (70% S units). The effect of electrostatic interactions in enzyme adsorption was investigated by SPR, which clearly indicated that the screening of charges allowed more extensive protein adsorption. Overall, this work furthers our understanding of lignin-cellulase interactions relevant to biomass that has been subjected to no or little pretreatment and highlights the widely contrasting effects of the nature of lignin, which gives guidance to improve lignocellulosic saccharification and related processes.}, number={4}, journal={BIOMACROMOLECULES}, author={Pereira, Antonio and Hoeger, Ingrid C. and Ferrer, Ana and Rencoret, Jorge and Rio, Jose C. and Kruus, Kristiina and Rahikainen, Jenni and Kellock, Miriam and Gutierrez, Ana and Rojas, Orlando J.}, year={2017}, month={Apr}, pages={1322–1332} }
 @article{ferrer_pal_hubbe_2017, title={Nanocellulose in packaging: Advances in barrier layer technologies}, volume={95}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2016.11.012}, abstractNote={The review aims at reporting on recent developments in nanocellulose-based materials and their applications in packaging with special focus on oxygen and water vapor barrier characteristics. Nanocellulose materials, including cellulose nanocrystals (CNC), nanofibrillated cellulose (NFC), and bacterial nanocellulose (BNC), have unique properties with the potential to dramatically impact many commercial markets including packaging. In addition to being derived from a renewable resource that is both biodegradable and non-toxic, nanocellulose exhibits extremely high surface area and crystallinity and has tunable surface chemistry. These features give nanocellulose materials great potential to sustainably enhance oxygen and water vapor barrier properties when used as coating, fillers in composites and as self-standing thin films.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Ferrer, Ana and Pal, Lokendra and Hubbe, Martin}, year={2017}, month={Jan}, pages={574–582} }
 @article{ferrer_salas_rojas_2016, title={Physical, thermal, chemical and rheological characterization of cellulosic microfibrils and microparticles produced from soybean hulls}, volume={84}, ISSN={["1872-633X"]}, DOI={10.1016/j.indcrop.2016.02.014}, abstractNote={Soybean hulls were used to isolate cellulosic microfibrils (SMF) and brick-like microparticles (SMP) by combining chemical and mechanical pretreatments. The key physical and chemical features of SMF and SMP were compared with those of micro and nanofibrillated cellulose (MNFC) obtained from fully bleached wood fibers. SMF and SMP chemical composition includes residual polysaccharides and lignin that endow such biologically-derived materials with properties typical of nanocellulosics. Compared to MNFC, SMF and SMP exhibit enhanced crystallinity (∼ > 10% higher) and thermal stability (onset degradation temperature >295 °C and maximum degradation at 361 and 355 °C). Such observations make SMF and SMP suitable for reinforcement in thermoplastic composites. A strong shear thinning behavior was observed for aqueous dispersions of SMF and SMP, revealing that these cellulose microstructures are of interest for rheology modification, coatings and films. Overall, the availability and low cost of biomass from residual soybean hulls constitutes a viable option for their use as a feedstock for the production and development of novel materials from SMF and SMP.}, journal={INDUSTRIAL CROPS AND PRODUCTS}, author={Ferrer, Ana and Salas, Carlos and Rojas, Orlando J.}, year={2016}, month={Jun}, pages={337–343} }
 @article{ferrer_hoeger_lu_rojas_2016, title={Reinforcement of polypropylene with lignocellulose nanofibrils and compatibilization with biobased polymers}, volume={133}, ISSN={["1097-4628"]}, DOI={10.1002/app.43854}, abstractNote={ABSTRACT}, number={34}, journal={JOURNAL OF APPLIED POLYMER SCIENCE}, author={Ferrer, Ana and Hoeger, Ingrid C. and Lu, Xiaomin and Rojas, Orlando J.}, year={2016}, month={Sep} }
 @article{ago_ferrer_rojas_2016, title={Starch-Based Biofoams Reinforced with Lignocellulose Nanofibrils from Residual Palm Empty Fruit Bunches: Water Sorption and Mechanical Strength}, volume={4}, ISSN={["2168-0485"]}, DOI={10.1021/acssuschemeng.6b01279}, abstractNote={Lignin-containing cellulosic nanofibrils (LCNF) were extracted from residual oil palm empty fruit bunches (EFB), an abundant but underutilized bioresource, by using a set of sulfur-free fractionation methods. The various types of isolated LCNF were used to reinforce starch-based biofoams. The incorporation of LCNF achieved remarkable increases, by a factor of 44 and 66, of the Young’s modulus and yield stress in compression mode, respectively. In addition, owing to the relatively lower hydrophilicity of residual lignin, water sorption by the composite biofoams was reduced with LCNF loading. The starch/LCNF nanocomposite biofoams displayed mechanical properties similar to those of polystyrene foams and therefore can potentially represent a sustainable and green alternative for packaging and insulation materials.}, number={10}, journal={ACS SUSTAINABLE CHEMISTRY & ENGINEERING}, author={Ago, Mariko and Ferrer, Ana and Rojas, Orlando J.}, year={2016}, month={Oct}, pages={5546–5552} }
 @article{ferrer_salas_rojas_2015, title={Dewatering of MNFC containing microfibrils and microparticles from soybean hulls: mechanical and transport properties of hybrid films}, volume={22}, ISSN={["1572-882X"]}, DOI={10.1007/s10570-015-0768-y}, number={6}, journal={CELLULOSE}, author={Ferrer, Ana and Salas, Carlos and Rojas, Orlando J.}, year={2015}, month={Dec}, pages={3919–3928} }
 @article{ferrer_vargas_jameel_rojas_2015, title={Influence of operating variables and model to minimize the use of anthraquinone in the soda-anthraquinone pulping of barley straw}, volume={10}, DOI={10.15376/biores.10.4.6442-6456}, abstractNote={Soda-anthraquinone (soda-AQ) pulping of barley straw was used to obtain cellulosic pulps for papermaking purposes. The identified parameters, or variables to be optimized, were operating time, anthraquinone concentration, and PFI refiner revolutions, and the influence of these operating variables on pulp properties was studied. A polynomial model that reproduced the experimental results with errors less than 6% was developed. Operating variables were found (46 min of processing time, 0.4 wt.% of anthraquinone concentration, and 3000 rpm of PFI revolution) that yielded competitive pulp properties (82 °SR beating grade number, 870 mL/g of viscosity, Kappa number of 13, 77 Nm/g of tensile index, and 30% ISO brightness) at reasonable chemical and energy costs. On the other hand, this study highlights the usefulness of this polynomial model as a method to minimize the use of anthraquinone in these pulping processes and to be able to predict what the pulp properties will be. For comparison purposes, new operating conditions were found, and the pulp properties still remain at a very good level for this cereal straw.}, number={4}, journal={BioResources}, author={Ferrer, A. and Vargas, F. and Jameel, H. and Rojas, O. J.}, year={2015}, pages={6442–6456} }
 @article{fritz_ferrer_salas_jameel_rojas_2015, title={Interactions between Cellulolytic Enzymes with Native, Autohydrolysis, and Technical Lignins and the Effect of a Polysorbate Amphiphile in Reducing Nonproductive Binding}, volume={16}, ISSN={["1526-4602"]}, DOI={10.1021/acs.biomac.5b01203}, abstractNote={Understanding enzyme-substrate interactions is critical in designing strategies for bioconversion of lignocellulosic biomass. In this study we monitored molecular events, in situ and in real time, including the adsorption and desorption of cellulolytic enzymes on lignins and cellulose, by using quartz crystal microgravimetry and surface plasmon resonance. The effect of a nonionic surface active molecule was also elucidated. Three lignin substrates relevant to the sugar platform in biorefinery efforts were considered, namely, hardwood autohydrolysis cellulolytic (HWAH), hardwood native cellulolytic (MPCEL), and nonwood native cellulolytic (WSCEL) lignin. In addition, Kraft lignins derived from softwoods (SWK) and hardwoods (HWK) were used as references. The results indicated a high affinity between the lignins with both, monocomponent and multicomponent enzymes. More importantly, the addition of nonionic surfactants at concentrations above their critical micelle concentration reduced remarkably (by over 90%) the nonproductive interactions between the cellulolytic enzymes and the lignins. This effect was hypothesized to be a consequence of the balance of hydrophobic and hydrogen bonding interactions. Moreover, the reduction of surface roughness and increased wettability of lignin surfaces upon surfactant treatment contributed to a lower affinity with the enzymes. Conformational changes of cellulases were observed upon their adsorption on lignin carrying preadsorbed surfactant. Weak electrostatic interactions were determined in aqueous media at pH between 4.8 and 5.5 for the native cellulolytic lignins (MPCEL and WSCEL), whereby a ∼20% reduction in the enzyme affinity was observed. This was mainly explained by electrostatic interactions (osmotic pressure effects) between charged lignins and cellulases. Noteworthy, adsorption of nonionic surfactants onto cellulose, in the form cellulose nanofibrils, did not affect its hydrolytic conversion. Overall, our results highlight the benefit of nonionic surfactant pretreatment to reduce nonproductive enzyme binding while maintaining the reactivity of the cellulosic substrate.}, number={12}, journal={BIOMACROMOLECULES}, author={Fritz, Consuelo and Ferrer, Ana and Salas, Carlos and Jameel, Hasan and Rojas, Orlando J.}, year={2015}, month={Dec}, pages={3878–3888} }