This book contributes as a rich source of information on the synthesis, main properties, toxicity and applications of Deep Eutectic Solvents (DESs). It covers the viable and sustainable use of these ...special solvents that due to the versatility of the preparation can be tuned for specific applications. Both hydrophilic and hydrophobic DESs are covered over the chapters. The book covers, in addition to the fundamentals of DESs, their use in extraction processes, in the pre-treatment of biomass, as solvents for catalytic processes and in processes for carbon dioxide capture, among others. The purpose of the book is it can reach a wide audience, so it can serve both as a reference for experienced professionals and to students interested in the field. In this sense, the book contributes to the state of the art in the application of DESs and addresses the challenges that must be faced for the industrial application of these special solvents.
Beer is a beverage that contains gluten and cannot be consumed by people with celiac disease. In this context, the enzyme prolyl endoprotease (PEP) can be used to reduce the gluten content in beer. ...The present study aimed to produce the PEP from Aspergillus sp. FSDE 16 using solid‐state fermentation with 5 conditions and comparing with a similar commercial enzyme produced from Aspergillus niger in the production of a gluten‐free beer. The results of the performed cultures showed that during the culture, the most increased protease activity (54.46 U/mL) occurred on the 4th day. In contrast, for PEP, the highest activity (0.0356 U/mL) was obtained on the 3rd day of culture in condition. Regarding beer production, cell growth, pH, and total soluble solids showed similar behavior over the 7 days for beers produced without enzyme addition or with the addition of commercial enzyme and with the addition of the enzyme extract produced. The addition of the enzyme and the enzyme extract did not promote changes, and all the beers produced showed similar and satisfactory results, with acid pH between 4 and 5, total soluble solids ranging from 4.80 to 5.05, alcohol content ranging from 2.83% to 3.08%, and all beers having a dark character with deep amber and light copper color. Gluten removal was effectively using the commercial enzyme and the enzyme produced according to condition (v) reaching gluten concentrations equal to 17 ± 5.31 and 21.19 ± 11.28 ppm, respectively. In this way, the production of the enzyme by SSF and its application in the removal of gluten in beer was efficient.
The present study focuses on elucidating the effects of ethylene oxide-based polymers on cellulosic ethanol production from green coconut fiber (GCF). Data on ethanol production, cell viability, ...adsorption of cellulases, and enzymatic digestibility were collected from experiments with high concentrations of PEG 4000 and poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) 5800 (EOPO 5800). PEG 4000 and EOPO 5800 favored cell viability and ethanol production in simulated experiments with S. cerevisiae CAT-1 and Kluyveromyces marxianus. Enzymatic hydrolysis under 175 g L−1 PEG 4000 increased the sugar release using untreated GCF (702.0%), hydrothermally-pretreated GCF (63.2%), and acid-pretreated GCF (40.1%). However, there were no benefits to using SigmaCell cellulose as the substrate. EOPO 5800 at 100 g L−1 had positive effects on cellulolytic activity preservation and on the sugar release during enzymatic hydrolysis. Both polymers provided higher ethanol titers for simultaneous saccharification and fermentation (SSF) of pretreated GCF compared to polymer-free experiments. A high ethanol yield (89.8%) was reached by the SSF of untreated GCF using 175 g L−1 PEG 4000. This result implies that high polymer concentrations may enable the cellulosic ethanol scheme without the need for pretreatment.
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•Fermentation with inhibitor was favored by PEG 4000 and EOPO 5800.•Polymers improved cellulolytic activity (>100%) and GCF enzymatic digestibility.•SigmaCell cellulose digestibility was impaired by high concentration of PEG 4000.•High ethanol yield (89.8%) was obtained from untreated GCF using PEG 4000.
Moringa oleifera seeds contain cationic proteins that can be used for water and wastewater treatment; furthermore, the oil content of Moringa oleifera seeds is high, and the properties of this oil ...render it useful for many applications. In this study, it was investigated the effects of oil extraction on the structure, composition, and coagulant activity of Moringa oleifera seeds, and aimed to add value to the seed waste generated after oil extraction. The results revealed that the content of fatty acids and phenolic and aromatic compounds of the seeds decreased after oil extraction. However, the proteins, including those with coagulant properties, were retained in the oil-extracted seeds. Oil extraction increased the operating pH range of the natural flocculant derived from Moringa oleifera seeds from below 4.8 for the flocculant derived from oil-containing Moringa oleifera (M1) seeds to below 9.8 for the flocculant derived from oil-extracted Moringa oleifera (M2) seeds. Furthermore, the performance of the M1 and M2 seeds for water treatment via coagulation followed by dissolved air flotation was not significantly different, and their mean oil and grease removal efficiency was approximately 82.43 ± 0.70%. These results confirmed the promising use of Moringa oleifera seed waste for the removal of oil and grease from wastewater as a more affordable, sustainable, and natural alternative to commercial flocculants. In addition, the concomitant use of both the extracted oil and seed waste generated after oil extraction was facilitated. More studies should be performed to assess whether the performance of the M1 and M2 seed-derived flocculants could be improved at the pH values we determined to be optimal for the purification of the protein of interest, viz. 9.5 and 4.0, respectively.
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•Effect of oil extraction in coagulant activity of Moringa oleifera seeds was studied.•Protein content of the seeds was not significantly affected after oil extraction.•Operational pH range of flocculant obtained using oil-extracted seeds was increased.•Oil extraction did not affect the coagulant activity of Moringa oleifera seeds.•Moringa oleifera seed waste had high performance for wastewater treatment.
The bioalcohol production (ethanol and butanol) from lignocellulosic biomass has some techno-economic limitations nowadays. Detoxification technologies can efficiently remove fermentation inhibitors ...(such as furan aldehydes, aliphatic acids, and phenolic compounds) to increase the bioalcohol titers. However, the addition of more steps before fermentation increases the complexity of the production scheme and reduces the profit margin. Process intensification concepts have been disseminated as a critical factor for the success of biotechnological processes, including bioalcohol production. Thus, this review discusses the main inhibitors from lignocellulosic biomass and the in-situ technologies used to minimize the yeast inhibition in hydrolysates and slurries. In-situ detoxification strategies involve different fundamentals, but they have the unanimity of allowing fermentation to be carried out concurrently. They are usually based on the establishment of a microbial consortium as well as the addition of reducing agents, polymers, solvents and adsorbents. Also, in-situ product recovery methods have been developed to minimize energy consumption in downstream processing.
•Process intensification is the basis of in-situ detoxification methods.•In-situ detoxification is an attractive way to treat inhibitor-rich hydrolysates.•Synergism is key to the success of the microbial consortium-based approach.•Phenolic compounds can be removed by using reducing agents or polymers.•In-situ product recovery techniques improve the high bioalcohol titers.
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•High ethanol concentrations were reached from green coconut fiber.•PEG 1500 improved the biomass liquefaction during SSF.•Enzyme activity was successfully reused by using ...high-concentration PEG.•Fed-batch with PEG 1500 favors SSF at high solid loading.
Efforts have been made to improve and modify lignocellulosic pretreatments, but this step corresponds to a high cost in second-generation ethanol production. Previous studies have shown that high-concentration polyethylene glycol (PEG) is a possible way to dispense chemical and physicochemical pretreatments and increase ethanol production from lignocellulosic material. However, no operational conditions of this strategy were optimized. The present study investigated the effects of operational conditions on simultaneous saccharification and fermentation (SSF) performance using high PEG concentrations and green coconut fiber (GCF) as a substrate. The high-concentration PEG (150 g.L−1) increased ethanol production compared to the PEG-free, 10, and 50 g.L−1 PEG conditions. Using 20 % (w.v−1) solid loading, the batch SSF cultivation with PEG 1500 and without supplementary nutrients reached ethanol production and ethanol yield equal to 22.21 g.L−1 and 64.0 %, respectively. The batch SSF cultivation with 30 % (w.v−1) solid loading presented mass transfer limitations. The addition of salts, yeast extract, or peptone improved ethanol production. Inhibition by ethanol on the Saccharomyces cerevisiae CAT-1 strain was indifferent to the presence of PEG 1500, while the addition of PEG ensured the cellulolytic activity reuse after three fermentation cycles. The fed-batch SSF with PEG facilitated the GCF liquefaction so that it was possible to operate with up to 30 % (w.v−1) solid loading without problems of viscosity and free water. Using 150 g.L−1 PEG 1500 and enzyme loading equal to 13.3 filter paper unit. g−1, the fed-batch SSF reached 35.1 g.L−1 ethanol at 48 h, representing an increase of 70 % compared to the fed-batch SSF without PEG.
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•Sequential Alk-H2O2/NaOH pretreatment was developed.•FTIR, SEM, X-ray and crystallinity indexes have evidenced modifications in solids.•Delignified MCF was more susceptible the ...enzymatic action.•SSSF strategy allowed to obtain higher ethanol production than SSF.•Step of presaccharification had a positive effect on the overall ethanol yield.
It is of the highest importance to study different alternatives/strategies as simultaneous (SSF) and semi-simultaneous (SSSF) saccharification and fermentation process, as well as the prospects of the utilization of lignocellulosic residues as raw materials for fuel-ethanol production. In the first part of this work, different raw materials (cactus (CAC), green coconut shell (GCS), mature coconut fibre (MCF) and mature coconut shell (MCS)) were pretreated by sequential alkaline hydrogen peroxide (Alk-H2O2)–sodium hydroxide (NaOH) process. The characterization of the obtained solids by FTIR, SEM, X-ray and crystallinity indexes confirmed the higher susceptibility of these pretreated materials to enzymatic action. These results were further confirmed by the corresponding glucose conversion yields – 68.44%, 70.20%, 76.21% and 74.50% for CAC, GCS, MCF and MCS, respectively. Subsequently, the comparison between SSF and SSSF using Saccharomyces cerevisiae, Pichia stipitis, Zymomonas mobilis and pretreated MCF (selected in the enzymatic hydrolysis step) was done, being shown that a short presaccharification step at 50°C for 8h in the SSSF had a positive effect on the overall ethanol yield, with an increase from 79.27–84.64% to 85.04–89.15%. In all the cases, the SSSF strategy allowed the obtention of higher ethanol concentrations than SSF.
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•LNPs were prepared by pH-shifting of soda lignins obtained from GCF and CC.•Pickering emulsions stabilized by LNP reached high E48 values (> 40 %).•The LNP recycling step did not ...affect the manufacture of polymer microcapsule.•GCF-LNP-coated hollow PCL microcapsule showed stability in dry ambient.•GCF-LNP showed high performance in removing emulsified oil (> 90 %).
Lignin-based materials have been explored as a way to minimize dependence on petroleum products and consolidate valorization schemes of lignocellulosic biomass. Soda lignins have peculiar properties and can generate lignin nanoparticles (LNP) with the potential ability to solve emulsification/demulsification problems. The present study focuses on the use of soda LNPs for fabrication of polymer microcapsules via Pickering emulsion template and for removing emulsified oil from aqueous environment. Structural characteristics of lignins recovered from corn cob (CC) and green coconut fibre (GCF) were evaluated after analyses of chemical composition, thermal degradation and infrared spectroscopy. Both LNPs were obtained by pH-shifting method and showed low absolute values of zeta potential. LNPs provided good emulsification capacity (emulsification index > 40 % at 5.00 g/L LNP) and micrometer-scale droplets in oil-water Pickering emulsions. LNPs have been successful as a stabilizing agent in the preparation of microcapsules of poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL), in which size was strongly dependent on the LNP concentration. Hollow PCL microcapsules were manufactured by stabilization with GCF-LNP, but did not show to be stable in experiments involving CC-LNP. In addition, the tendency of soda LNPs to form aggregates was used as a mechanism to remove emulsified oil, which made it possible to remove up to 90.6 % for CC-LNP and 94.4 % for GCF-LNP experiments.
The effects of different hydrothermal pretreatments on the physical chemical characteristics and drying kinetics of red rice starch (Oryza sativa L.) were investigated. The hydrothermal pretreatments ...chosen include the cooking, autoclave, and steam explosion processes. To obtain the starch in powder form, the pastes were dried at a temperature of 50°C with an air speed of 1.0 m/s. The mathematical models (empirical and diffusive) were adjusted to the experimental data. The starches were submitted to extraction yield, color, water binding capacity, and proanthocyanidins. The values for the diffusivity are between 3.08 × 10−7 and 2.74 × 10−6 m2/min for treatments. The pretreatments of cooking in the grain and autoclave in the starch gave better results than the other studied treatments (formulations), presenting shorter drying time (450 and 510 min) and higher yield (48.60% and 53.54%), respectively. With the application of pretreatments, it is possible to save energy and reduce thermal damage.
Novelty impact statement
The results obtained in this study reveals the application autoclave pre‐treatment in red rice starch effectively saves energy and reduces thermal damage as the drying time is shortened. In addition, the drying process information can be used when designing future new equipments.
•Scanning Electron Microscopy (SEM) qualitatively characterized the biomass.•Alkaline pretreatment allowed the best the enzymatic hydrolysis yield.•Nopalea cochenillifera showed better yield ...performance during SSF.•PE-2 is more thermo-tolerant than the CA-11 strain.
Lignocellulosic biomasses of two species of cactus pear (Opuntia ficus indica and Nopalea cochenillifera) were tested for the production of ethanol. Their ability to grow in water-stressed regions makes them eligible for reducing the production cost of biofuels in drought regions. The biomass was pretreated using three different strategies: alkaline hydrogen peroxide, alkaline using NaOH, and acid using H2SO4 followed by alkaline delignification with NaOH. Analyses of the composition, crystallinity, and enzymatic hydrolysis were performed on the material before and after pretreatment. An experimental design was used to evaluate the influence of temperature and initial cellulose concentration on the process of simultaneous saccharification and fermentation (SSF) using the pretreated material, which showed the best performance in previous tests, and two strains of Saccharomyces cerevisiae (PE-2 and LNF CA-11). Biomass characterization showed a content of 31.55% cellulose, 17.12% hemicelluloses, and 10.25% lignins for N. cochenillifera and 34.86% cellulose, 19.97% hemicelluloses, and 15.72% lignins for O. ficus indica. The alkaline pretreatment provided the best enzymatic saccharification yields. The SSF experiments resulted in the greatest cellulose-to-ethanol yields using strain PE-2 with the pretreated N. cochenillifera (93.81%) at 40°C and an initial cellulose concentration of 4%. N. cochenillifera showed better yields than O. ficus indica, and the PE-2 strain performed better than CA-11. These results suggest a good potential for cactus pear cladodes in the production of cellulosic ethanol.
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