Polysaccharide fractions isolated from L. tessellatus eggs were purified and eluted using the DEAE-sepharose fast flow column. These were collected, tested and pooled based on their sugars content: F1, F2, and F3 which contain 26.8, 23.3, and 20.2% sulfated glycans; 34.5, 38.2, and 45.0% uronic acids; and 23.5, 19.0, and 7.5% acetylhexosamines and hexosamines, respectively. Hyaluronidase inhibitory effects of the fractions are in the order F3 > F2 > F1 > Ascorbic acid, with F3 having the highest inhibition among the fractions and that of the standard, ascorbic acid. The electrospray ionization tandem mass spectrometry (ESI-MS/MS) confirmed the presence of uronic acids on F3, which could be a ^0,2A₂ fragment plus loss of methyl group which is very common among non-methylated, sulfated disaccharides.

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Autohydrolysis, which is an eco-friendly technology that employs only water as extraction solvent, was used to extract antioxidant phenolic compounds from spent coffee grounds (SCG). Experimental assays were carried out using different temperatures (160–200 °C), liquid/solid ratios (5–15 ml/g SCG) and extraction times (10–50 min) in order to determine the conditions that maximize the extraction results. The optimum conditions to produce extracts with high content of phenolic compounds (40.36 mg GAE/g SCG) and high antioxidant activity (FRAP = 69.50 mg Fe(II)/g SCG, DPPH = 28.15 mg TE/g SCG, ABTS = 31.46 mg TE/g SCG, and TAA = 66.21 mg α-TOC/g SCG) consisted in using 15 ml water/g SCG, at 200 °C during 50 min. Apart from being a green technology, autohydrolysis under optimized conditions was demonstrated to be an efficient method to extract antioxidant phenolic compounds from SCG.

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The extraction of polysaccharides by autohydrolysis of spent coffee grounds (SCG) was studied. Experimental assays were performed using different temperatures (160–200 °C), liquid/solid ratios (5–15 ml water/g SCG) and extraction times (10–50 min) in order to determine the conditions that maximize the extraction of polysaccharides with high antioxidant activity. Autohydrolysis was demonstrated to be an efficient technique to recover antioxidant polysaccharides from SCG. The best process conditions consisted in using 15 ml water/g SCG, during 10 min at 160 °C. The polysaccharides obtained under these conditions were mainly in the form of galactomannans and arabinogalactans. They presented high antioxidant activity (assessed by four different methods), were thermostable in a large range of temperature, and had a typical carbohydrate pattern, being of interest for industrial applications, mainly in the food area.

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A mild alkaline pretreatment (deacetylation) prior to the dilute acid pretreatment was evaluated as a strategy to improve the sugars recovery and ethanol production from both hemicellulose and cellulose fractions of rice straw. This pretreatment was carried out using different conditions of temperature (50-70°C) and NaOH loading (20-80mg NaOH/g biomass), which were combined according to a 2² central composite design. In this step the removal of acetyl groups as well as the impact of this step on biomass composition were evaluated. In order to assess the impact of the deacetylation on hemicellulosic hydrolysate composition, the influence of the reaction time (30-90min) and sulfuric acid concentration (0.5-1.5% w/v) was also studied, using the alkaline-pretreated solid (deacetylated) and rice straw in natura. The best sequential pretreatment conditions were scaled-up to 50-L reactor, being obtained a cellulose-rich pretreated solid (cellulignin) and a hemicellulosic hydrolysate, which was concentrated to 70g/L xylose to be used as fermentation medium. A significant improvement on ethanol production from xylose by Scheffersomyces stipitis NRRL Y-7124 was observed when the biomass was submitted to deacetylation (about 4-fold). The enzymatic conversion of cellulose was also improved (from 73 to 89%) when the deacetylated cellulignin was used, resulting in an enhancement of the ethanol production (from 12.7 to 20.4g/L) during the simultaneous saccharification and fermentation with Kluyveromyces marxianus NRRL Y-6860. In brief, biomass deacetylation prior to dilute acid pretreatment was an efficient strategy for rice straw processing, substantially improving the ethanol production from both pentose and hexose sugars.

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In the present study, an acid mediated steam explosion process was evaluated for pretreatment of elephant grass biomass in a bench scale reactor. Different combinations of H₂SO₄ concentration, reaction time and temperature (leading to different values of combined severity factor - CSF) were used for biomass pretreatment, and the impact of the resultant pretreatment conditions on biomass composition, structure and enzymatic hydrolysis was assessed. The optimal pretreatment conditions consisted in performing the steam explosion at 161°C during 11.5min, and using the biomass impregnated with 0.5% H₂SO₄ (CSF=1.42). Under these conditions, a pretreated solid containing 52.13% (w/w) cellulose and 31.00% (w/w) lignin was obtained. The modifications in the biomass structure resulting from the different pretreatment conditions were evaluated by scanning electron microscopy, thermogravimetric analysis and nuclear magnetic resonance spectroscopy analysis. Enzymatic hydrolysis of the pretreated material resulted in a cellulose saccharification yield of 55%. These results allow a better understanding about the pretreatment and enzymatic saccharification of elephant grass biomass and also reveal a great potential of this raw material for use in a biorefinery.

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Production of aviation biofuels has been strongly encouraged by the volatility of oil prices and environmental concerns. Brazilian society, companies, and government are taking a step forward in the production of renewable jet fuel from biomass feedstocks largely available in the territory. This study evaluated the use of different feedstocks (sugar crops, oil crops, and lignocellulosic biomass) for co-production of biojet fuel and higher value-added products in a biorefinery platform. The co-production of biofuels and biochemicals in a biorefinery context was demonstrated to be economically feasible. The main cost drivers of such a platform are feedstock biomass cost, selling price of the biochemicals, investment costs, and key process-inherent parameters such as conversion yields, obtained fermentable sugars, or oil content in the feedstock. Sugarcane was the most promising feedstock for a biorefinery in the region of Minas Gerais, while soybean was the most promising feedstock for a biorefinery in the region of Rio Grande do Sul, despite its higher uncertainty. Succinic acid was the most promising chemical intermediate for biopolymers industry due to its relatively high market value, unique market opportunity as a substitute of conventional petrochemicals, and forecast for future growth. Ethanol-to-jet (ETJ) and hydro-processed esters and fatty acids (HEFA) were the most attractive biojet fuel production routes in the present study. Scenarios for co-production of biofuels and biochemicals in Brazil present large uncertainties and high financial risk, mainly due to the use of second-generation feedstocks, and the introduction of new technologies and products.

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Several strategies based on a two steps organosolv pretreatment followed by enzymatic hydrolysis of sugarcane bagasse (SCB) were evaluated with the objective of selecting operational conditions suitable to promote an efficient and low cost production of ethanol. Initially, the influence of six variables used for the organosolv pretreatment was studied. The variables included the time of the first organosolv pretreatment step, the use of 45% ethanol as pulping solution, solid-to-liquid ratio of the ethanol solution used during the first pretreatment step, time of second organosolv pretreatment, concentration of ethanol and concentration of NaOH solution used in the second pretreatment step. Further assays of enzymatic hydrolysis were carried out to promote additional reduction in the costs of the process and improve the results of cellulose conversion to glucose. Eliminating the milling step of the pretreated SCB, using a commercial tensoactive (composed of esters and several surfactants), and recycling 50% of the slurry obtained during the second step of organosolv pretreatment as reaction medium proved to be feasible for use during the enzymatic hydrolysis. Fermentation of the glucose medium produced under the selected pretreatment conditions to ethanol by Saccharomyces cerevisiae occurred with 81% efficiency and a cost of 102.88 $/hL of ethanol.@en

Cells of Candida guilliermondii permeabilized with Triton X-100 were able to efficiently produce xylitol from a medium composed only by d-xylose and MgCl₂·6H₂O in potassium phosphate buffer, at 35 °C and pH 6.5. Under these conditions, the results were similar to those obtained when cofactor and co-substrate or nutrients were added to the medium (about 95 % d-xylose was assimilated producing 42 g/L of xylitol, corresponding to 0.80 g/g yield and 2.65 g/L h volumetric productivity). Furthermore, the permeabilized cells kept the d-xylose assimilation in about 90 % and the xylitol production in approx. 40 g/L during three bioconversion cycles of 16 h each. These values are highly relevant when compared to others reported in the literature using enzyme technology and fermentative process, thereby demonstrating the effectiveness of the proposed method. The present study reveals that the use of permeabilized cells is an interesting alternative to obtain high xylitol productivity using low cost medium formulation. This approach may allow the future development of xylitol production from xylose present in lignocellulosic biomass, with additional potential for implementation in biorefinery strategies.

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In this study, a new method for isolation of polyphenols (PP) from spent coffee grounds (SCG) and coffee silverskin (CS) is described. The method consisted of a mild hydrothermal pretreatment at 120°C, for 20 min, using a liquid-to-solid ratio of 20 mL/g. PP (determined as gallic acid equivalents, GAE) were the most abundant components in the extracts produced by this method, corresponding to 32.92 mg_GAE/g_SCG and 19.17 mg_GAE/g_CS, among which flavonoids corresponded to 8.29 and 2.73 mg quercetin equivalents/g of SCG and CS, respectively. Both extracts presented antioxidant activity but the results were higher for SCG extract, probably due to the highest content of PP present. Negligible effects (less than 1% solubilization) were caused by the hydrothermal pretreatment on cellulose, hemicellulose, and protein fractions of these materials. Some mineral elements were present in the extracts, with potassium being the most abundant. Hydrothermal pretreatment under mild conditions was demonstrated to be an efficient method to recover antioxidant PP from coffee residues.

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A wide variety of different feedstocks and conversion technologies may be used in a biorefinery to produce fuel, chemicals, feed, and power or heat. Biorefineries can also have a wide range of capacities and, given the dependency on technological innovation, funding, and market conditions, it is difficult to predict their future prospects. In this sense, technoeconomic assessment is an essential tool for the designing of an economically viable biorefinery with a long-term perspective, since it provides decision-making information for the corresponding steps of the investment. In this chapter, the technoeconomic considerations of advanced biorefinery concepts are presented and discussed. Focus is given to how technoeconomic assessment influences the design decisions and challenges for establishing novel technologies. The economics of current biomass fractionation methods, fuels, and biochemical production technologies are also presented. Finally, the current trends on improving the economics of biorefineries are discussed, as an attempt to help the reader identify synergies and opportunities for further improvement strategies.

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The aim of this work was to improve the production of fructosyltransferase (FTase) by Solid-State Fermentation (SSF) using aguamiel (agave sap) as culture medium and Aspergillus oryzae DIA-MF as producer strain. SSF was carried out evaluating the following parameters: inoculum rate, incubation temperature, initial pH and packing density to determine the most significant factors through Box-Hunter and Hunter design. The significant factors were then further optimized using a Box-Behnken design and response surface methodology. The maximum FTase activity (1347U/L) was obtained at 32°C, using packing density of 0.7g/cm³. Inoculum rate and initial pH had no significant influence on the response. FOS synthesis applying the enzyme produced by A. oryzae DIA-MF was also studied using aguamiel as substrate.

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The search for microorganisms able to produce thermostable xylanases with high yield and characteristics desired for industrial applications has been strongly encouraged since such enzymes are widely used in large-scale processes. In the present study, thermophilic fungal strains able to grow at high temperatures (≥55 °C) were isolated from maize silage. The strains were molecularly identified and used for the production of extracellular xylanase by solid-state fermentation using corn cobs as support-substrate material. Species from the genera Rhizomucor and Aspergillus were identified among the isolated strains and these species demonstrated good ability to produce xylanase under solid-state fermentation conditions. Maximal values of enzymatic activity (824 U/g) and productivity (8.59 U/g.h) were obtained with Rh. pusillus SOC-4A (values per g dry weight of fermented medium). The xylanase produced by this fungus presented thermal stability at 75 °C, with maximum activity at 70 °C and pH 6.0, revealing, therefore, great potential for application in different areas.

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In a lignocellulosic-based biorefinery, the stage related to biomass pretreatment is one of the most important and has attracted great attention due to its influence on technical, economic, and environmental aspects. Although a number of different processes involving physical, chemical, physicochemical, and biological methods have been investigated over the years, those employing chemicals, especially acid solutions, are demonstrated to be highly effective in attacking the lignocellulosic structure, offering the highest sugar yields with the lowest costs that are fundamental to attaining economic success. Pretreatment with acids, especially with sulfuric acid, has been one of the most widely used methods for biomass pretreatment. The goal of this chapter is to provide an overview of the technique of biomass pretreatment with acids. A description of the process using dilute and concentrated acid solutions, major effects on biomass structure, advantages and drawbacks, and the most recent advances/future perspectives for the use of this technique on an industrial scale are discussed.

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Xylitol is a pentahydroxy sugar alcohol coming from xylose with many applications in the food and pharmaceutical industries as a low caloric sweetener suitable for diabetics and as an active ingredient in several biomedical applications. The microbial bioproduction of xylitol from natural xylose coming from lignocellulosic materials appears a sustainable and a promising alternative to chemical synthesis, which works at stronger reaction conditions and generates undesirable co-products which must be removed. There are several reviews that study the metabolic pathways in wild and transformed xylitol producing yeasts and the culture conditions that enhance xylitol accumulation, which are mainly related to the need of microaerobiose for the best producing wild yeasts. Nevertheless, there are relatively few studies focusing on the engineering aspects related to scalable systems and bioreactors that could result in a final industrial stage. This review explores recent advances on xylitol production using immobilized systems, which have been proposed to facilitate the reuse of the biocatalyst for extended periods and the main types of bioreactors available assayed for this purpose.
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