Eucalyptus wood and cheese whey valorization for biofuels production

In this work, two raw materials (Eucalyptus wood and cheese whey) were used for ethanol production. Eucalyptus wood was hydrothermally pretreated at 233 ºC in order to increase the enzymatic saccharification of cellulose. Pretreated Eucalyptus wood mixed or not with cheese whey were used as substrates for ethanol production by simultaneous saccharification and fermentation (SSF) using two Saccharomyces cerevisiae strains (industrial Ethanol Red® and laboratory CEN.PK1137D). The use of cheese whey mixed with Eucalyptus wood increased 1.3 and 1.5-fold the ethanol concentration in comparison with Eucalyptus without cheese whey using S. cerevisiae Ethanol Red® and CEN.PK113 7D strains, respectively. Higher ethanol concentration was obtained by Ethanol Red® than ethanol produced by CEN.PK113-7D with cheese whey supplementation (93 g/L and 65 g/L corresponding to 94 % and 66 % of ethanol yield, respectively). Results obtained in this work showed an interesting strategy for the valorization of two raw materials in order to produce high concentrations of ethanol.Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI -01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01- 0145-FEDER -000004) funded by European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Biotechnological production of xylitol: engineering industrial Saccharomyces cerevisiae for valorization of lignocellulosic biomass

The use of renewable biomass, such as lignocellulosic materials, for the production of biofuels and chemicals within a biorefinery scheme contributes to achieve a sustainable development. Xylitol has been identified as one of the top 12 value added chemicals to be obtained from biomass, and can be produced from hemicellulose-derived xylose through biotechnological processes [1]. In this work, xylitol was produced from xylose (using glucose as co-substrate for co-factor regeneration) in batch fermentations by the industrial Saccharomyces cerevisiae PE-2 strain (over)expressing (1) a wild type xylose reductase from Pichia spititis (XR); (2) a NADH-preferable xylose reductase mutant (mut-XR) from Pichia spititis and (3) the endogenous GRE3 gene which encodes for an unspecific aldose reductase (AR). Maximum yield (0.98 g g-1) was obtained by the strain overexpressing the GRE3 gene. Moreover, the recombinant strain PE-2-GRE3 showed significantly higher xylitol productivity than the laboratory strain, CENPK.113-5D overexpressing the same gene. This strain (PE-2-GRE3) was selected for bioconversion of 160 g L-1 of xylose in a fed-batch fermentation, which resulted in 149 g L-1 of xylitol concentration with a productivity of 1.2 g L-1 h-1. These results open new perspectives and opportunities for the valorisation of hemicellulosic hydrolysates through the production of xylitol within a biorefinery concept.info:eu-repo/semantics/publishedVersio

Integral valorization of Acacia dealbata wood in organic medium catalyzed by an acidic ionic liquid

In this work, a novel delignification process was proposed for the fractionation of invasive species such as Acacia dealbata wood. Organosolv process catalyzed with an acidic ionic liquid, 1-butyl-3-methylimidazolium hydrosulfate was evaluated to obtain cellulose-enriched solids and liquid fractions rich in hemicelluloses derived compounds and lignin. Under selected operating conditions (190 °C, 60% ethanol, 60 min of reaction time and 0.6 g 1-butyl-3-methylimidazolium hydrosulfate/g wood), high solubilization of lignin and hemicelluloses and cellulose recovery (87.5%, 88.7% and 88.3%, respectively), with a pulp yield of 43.1% were achieved. Moreover, 62.6 % of lignin was recovered by precipitation from the black liquor (composed mainly by 4.43 g xylose/L, 7.66 g furfural/L and 3.59 g acetic acid/L). In addition, enzymatic digestibility of delignified wood was also assayed. Overall, this work presents an alternative biorefinery scheme based in the use of environmentally friendly solvent and catalyst for selective fractionation of A. dealbata wood.The authors acknowledge the financial support received from the Spanish “Ministry of Economy and Competitiveness” (Project CTQ2017- 82962-R) and from “Xunta de Galicia” (GRC ED431C 2018/47 and Centro Singular de Investigacion ´ Biom´edica “CINBIO”). These projects are partially funded by the FEDER Program of the European Union (“Unha maneira de facer Europa”). A. Romaní thanks BioTecNorte operation (NORTE-01–0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Bioethanol production from whole slurry of hydrothermally treated brewer´s spent grain at high solid loadings

Portuguese Foundation for Science and Technology (FCT) under the scope of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684), the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Authors acknowledge Fermentum-Engenharia das Fermentações Lda. for providing the raw materials usedinfo:eu-repo/semantics/publishedVersio

Polyphenols and sugars recovery from autohydrolysis of pineapple waste

[Excerpt] The aim of this research was to evaluate the influence of temperature, time and mass/ volume ratio on the release of sugars and polyphenols using an autohydrolysis procedure from pineapple waste. A Box-Bhenken design was used with three factors (time, temperature and mass/volume ratio) and three levels was used. All treatments were performed in triplicate. Nine central points were used. For autohydrlosysis treatments, an oil bath was used [1]. After autohydrolysis, liquid phases or hydrolysates were analyzed for glucose and fructose concentration by high performance liquid chromatography (HPLC) [2]. The FolinCiocalteu assay was used to measure total polyphenols of hydrolysates [3] and HPLC to identify these molecules [4]. (...

Bioethanol production from vine pruning residue by sequential steps of autohydrolysis

Lignocellulosic biomass is a renewable raw material, widespread and with a huge potential for the manufacture of biofuels as bioethanol. In Portugal, the most abundant exploitable lignocellulosic biomass derives from the agro-industrial and forestry sectors. Large amounts of residues are generated during wine processing, specially pruning residues of vine. Approximately 1.2-3.5 t/ha of vine pruning residues (VPR) are estimated to be produced per year, which are usually burnt in the field. VPR are composed by 30.6 % of cellulose, 18.2 % of hemicellulose and 29.5 % of lignin. In order to produce ethanol from this agro-industrial residue, autohydrolysis treatment in two sequential steps were proposed for solubilization of hemicellulose in a separate stream and improving the enzymatic susceptibility of cellulose following the biorefinery concept. In a first stage, VPR was submitted to autohydrolysis treatment at 180 ºC for 60 min (Severity factor, So=4.13) at liquid to solid ratio = 6 g of distilled water/g of VPR. In liquid phase, 55 g of xylan/100 g of xylan in raw material was recovered as xylooligosaccharides (13 g/L). Autohydrolyzed VPR was evaluated in a second step of autohydrolysis treatment under temperature in the range 180- 200 ºC and time 30-40 min. After sequential treatments, 90-99 % of cellulose was recovered in solid phase and enzymatic saccharification of pretreated solid was assayed using 25 FPU/g of cellulase CTec2 and solid loading of 5 and 10 % of pretreated VPR. Sequential treatment of VPR significantly improved the enzymatic hydrolysis of cellulose from 70 % to 100 % of cellulose to glucose conversion for second autohydrolysis at 200 ºC for 30 min. Under these conditions of pretreatment, two configurations of saccharification and fermentation (simultaneously –SSF- and separately –SHF-) were carried out. Ethanol production was successfully obtained from two processes achieving cellulose to ethanol conversion of 93 and 97 % for SHF and SSF, respectively

Autohydrolysis extraction of bioactive compounds from pineapple waste

The aim of this research was to evaluate the influence of temperature, time and mass/volume ratio on the release of sugars and polyphenols using an autohydrolysis procedure from pineapple waste and determine its antioxidant activity. A Box-Bhenken design was used with three factors (time, temperature and mass/volume ratio) at three levels. All treatments were performed in triplicate. For autohydrolysis treatments, an oil bath was used [1]. After extraction process, liquid phases or hydrolysates were analyzed for glucose and fructose concentration by high performance liquid chromatography (HPLC) [2]. The Folin-Ciocalteu assay was used to measure total polyphenols of hydrolysates [3] and HPLC to identify these molecules [4]. Free radical scavenging activity (DPPH assay) and radical cation decolorization assay (ABTS) were assayed [5]. Figure 1, shows the antioxidant activity obtained from experimental matrix Box-Bhenken design from autohydrolysis treatments of pineapple waste. It was observed most treatments have higher activity than control, this is due to the abundance of bioactive compounds present in the hydrolysates. Conclusion: Autohydrolysis process is a good alternative for an effective extraction (using water as only reaction medium) of value-added compounds that can be used for alcoholic drinks enriched with natural antioxidants. In addition, this technology is an environmentally friendly extraction alternative in compared with traditional chemical process

Arabitol production from lignocellulosic biomass through GRE3-overexpressing industrial Saccharomyces cerevisiae strains

Arabitol is a five carbon sugar alcohol that belongs to the pentitol family, the same of xylitol and ribitol, being one of the top 12 biomass-derivable building block chemicals. Due to its sweetness similar to glucose and low caloric content (0.2 kcal/g) it is used as an alternative sweetener in food industry [1]. The concerns about the depletion of fossil fuel reserves and the economic and environmental problems associated with their use have led to the search of renewable energy sources. Lignocellulosic biomass emerged as sustainable alternative for the production of value-added products, once lignocellulose is one the most abundantly renewable biomass available on earth. Thus, the development of a lignocellulose-based bioeconomy must compromise the valorisation of lignocellulosic biomass for the production of value-added products [2]. Currently, arabitol is industrially produced by chemical reduction of lactones [3]. However, bioconversion of sugars present in lignocellulosic biomass to arabitol could be a viable alternative to chemical production. An endogenous aldose reductase from Saccharomyces cerevisiae, with a broad substrate specificity, was previously reported to be able to convert xylose and arabinose to xylitol and arabitol, respectively [4,5]. In here, we demonstrate the feasibility of using an engineered yeast strain overexpressing an aldose reductase gene for the conversion of arabinose to arabitol. Due to the unspecificity of the enzyme, arabinose and xylose could be simultaneously converted to arabitol and xylitol, respectively, which can lead to the development of a multi-chemical yeast production platform, contributing to the establishment of a lignocellulose-based bioeconomy.Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit, BioTecNorte operation (NORTE-01-0145- FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, COMPETE 2020 (POCI-01-0145-FEDER-006684) and MultiBiorefinery project (POCI-01-0145-FEDER-016403)info:eu-repo/semantics/publishedVersio

Boosting bioethanol production from Eucalyptus wood by whey incorporation

The mixture of Eucalyptus globulus wood (EGW) and cheese whey powder (CWP) was proposed for intensification of simultaneous saccharification and fermentation (SSF) at high temperature and solid loadings using the industrial Saccharomyces cerevisiae Ethanol Red® strain. High ethanol concentration (93 g/L), corresponding to 94% ethanol yield, was obtained at 35 °C from 37% of solid mixture using cellulase and -galactosidase enzymes (24.2 FPU/g and 20.0 U/g, respectively). The use of CWP mixed with pretreated EGW increased the ethanol concentration in 1.5-fold, in comparison with SSF experiments without CWP for both Ethanol Red® and CEN.PK1137D strains. Moreover, 1.4-fold higher ethanol concentration was obtained with Ethanol Red®, in comparison with CEN.PK113-7D strain. Ethanol Red® strain was genetically engineered for -galactosidase production in order to advance towards a fully integrated process. This work shows the feasibility of attaining high ethanol concentrations in second generation bioprocesses by a multi-waste valorization approach.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/ BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio