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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

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 is a lignocellulosic residue from pulp and paper mills consisting of cellulosic fibers and ash. However, the high ash content (35%, mainly CaCO3) and pH value affect the enzymatic hydrolysis of cellulosic fibers. Several pretreatments were used to reduce the CaCO3 content and to adjust the pH. Enzymatic hydrolysis of primary sludge was enhanced when it was pretreated with HCl or spent acid (another residual stream of the same plant). Cellulosic fibers were converted to monomeric sugars by Cellic CTec2 cellulase with a dosage of 35 FPU gCH–1 for a carbohydrate concentration of 46 g L–1. This conversion was enhanced from 20% to 88% for primary sludge pretreated with HCl and to 72% for samples pretreated with spent acid. The fermentation of 27 g L–1 of available sugars with Pichia stipitis led to ethanol concentrations of up to 10.5 g L–1 with a yield of 0.39 gEtOH gsug–1.