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This paper is dedicated to the memory of A. T. Portugal, the University of Coimbra leader of Multibiorefinery project, for his partnership and commitment

The purpose of this work was the valorization of wood/wastes of two invasive tree species, namely Acacia dealbata and Ailanthus altissima, in the production of polyelectrolytes as high value-added products for a range of applications. Kraft cooking of wood chips followed by the introduction of quaternary ammonium groups into the cellulose backbone using a typical sodium periodate oxidation/Girard’s reagent T cationization was performed. Water-soluble polyelectrolytes were obtained with a cationic group content of 3.0–3.6 mmol/g which were characterized, and, as a proof of concept, evaluated as flocculants in the treatment of an industrial effluent from olive oil mill, a harsh and difficult to treat effluent. Under optimized conditions of pH (4.5–7) and flocculant dosage (50−100 mg/L), an effluent turbidity removal of up to 65 % was achieved. The proposed approach enabled to obtain, for the first-time, valuable polyelectrolytes from very low value woods, with potential interest for application as flocculants in effluent treatment. Additionally, the experiments also proved that there is no need to completely remove lignin from wood before cationization, mild deconstruction procedures allowing to produce water-soluble polyelectrolytes and achieve a good performance in the flocculation process.

Pinus pinaster wood (PPW) was fractionated by two different routes: (1) a two-steps system by soda ethanol organosolv (SEOS) followed by lignin precipitation (LP) and (2) a three-steps procedure encompassing autohydrolysis (AH) followed by SEOS and LP. In the two-steps route, the effect of ethanol mass fraction in the cooking liquor (15-55 wt.%) on pulps and lignins purities was studied. In the three-steps system, the effects of AH temperature (160-180 °C) and reaction time (30 and 60 min) on hemicelluloses removal were evaluated. Then the effects of AH temperature (175 and 180 °C) and ethanol concentration (15-35 wt.%) on SEOS derived pulps and lignins purities were considered. The SEOS reaction temperature (170 °C) and time (90 min) were kept constant in all SEOS experiments. In the case of the two-steps approach, pulps with lignin and hemicellulose contents as low as 6 and 15 wt.% (respectively), as well as precipitates having lignin contents up to 94 wt.% were obtained. Up to 81 wt.% of the cellulose and 66 wt.% of the lignin initially present in PPW were recovered in pulps and precipitates (respectively) by this fractionation pathway. When the three-steps fractionation was applied, up to 17 wt.% of the original biomass was recovered in AH liquors. Pulps having hemicellulose contents as low as 3 wt.% and lignin contents as low as 5 wt.% were produced by sequential AH and SEOS, while LP products presented lignin contents higher than 98 wt.%. The results show the potential of the three-steps fractionation towards a biorefinery-based bioeconomy.

Made available in DSpace on 2018-11-26T17:06:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-11-01 project Energy and Mobility for Sustainable Regions - EMSURE Primary sludge, from different pulp and paper mills, was used as feedstock in simultaneous saccharification and fermentation (SSF) processes to produce ethanol. SSF was carried out with Saccharomyces cerevisiae ATCC 26602 yeast and NS 22192 enzymatic extract using 150 g L-1 of carbohydrates (CH) from primary sludge. The effect of sterilization, reduction of enzyme dosage and fed-batch vs. batch conditions were studied. The removal of sterilization can be considered since no contamination or atypical by-products were observed, although SSF efficiency slightly decreased. The reduction of the enzyme dosage from 35 to 15 FPU g(CH)(-1) was successful. Despite of initial mixing difficulties, batch SSF enabled higher ethanol concentration (41.7 g L-1), conversion yield (48.9%) and productivity (0.78 g L-1 h(-1)), compared to the fed-batch process at the same conditions of low enzyme dosage of 5 FPU g(CH)(-1) and high solids content of 21.7%, rarely found in literature. Published by Elsevier Ltd. Univ Coimbra, Fac Sci & Technol, CIEPQPF, Dept Chem Engn, Polo 2,Rua Silvio Lima, P-3030790 Coimbra, Portugal Sao Paulo State Univ, Dept Engn & Food Technol, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Sao Paulo State Univ, Dept Engn & Food Technol, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil project Energy and Mobility for Sustainable Regions - EMSURE: CENTRO-07-0224-FEDER-002004

Primary sludge from a Portuguese pulp and paper mill, containing 60% of carbohydrates, and unbleached pulp (as reference material), with 93% of carbohydrates, were used to produce ethanol by simultaneous saccharification and fermentation (SSF). SSF was performed in batch or fed-batch conditions without the need of a pretreatment. Cellic® CTec2 was the cellulolytic enzymatic complex used and Saccharomyces cerevisiae (baker's yeast or ATCC 26602 strain) or the thermotolerant yeast Kluyveromyces marxianus NCYC 1426 were employed. Primary sludge was successfully converted to ethanol and the best results in SSF efficiency were obtained with S. cerevisiae. An ethanol concentration of 22.7 g L−1 was produced using a content of 50 g L−1 of carbohydrates from primary sludge, in batch conditions, with a global conversion yield of 81% and a production rate of 0.94 g L−1 h−1. Fed-batch operation enabled higher solids content (total carbohydrate concentration of 200 g L−1, equivalent to a consistency of 33%) a...