RESUMEN

Feedstock characteristics impact biochar physicochemical properties, and reproducible biochar properties are essential for any potential application. However, in most articles, feedstock aspects (i.e., taxonomic name of the species, part of the plant, and phenological phase) are scarcely reported. This research aimed at studying the effect of species and phenological stage of the feedstock on the properties of the derived biochars and, thus, adsorption capacities in water treatment. In this study, we analysed the anatomical characteristics of three different woody bamboo species [Guadua chacoensis (GC), Phyllostachys aurea (PA), and Bambusa tuldoides (BT)] in culms harvested at two different phenological phases (young and mature), and statistically correlated them with the characteristics of the six derived biochars, including their adsorption performance in aqueous media. Sclerenchyma fibres and parenchyma cells diameter and cell-wall width significantly differed among species. Additionally, sclerenchyma fibres and parenchyma cell-wall width as well as sclerenchyma fibre cell diameters are dependent on the phenological phase of the culms. Consequently, differences in biochar characteristics (i.e., yield and average pore diameter) were also observed, leading to differential methylene blue (MB) adsorption capacities between individuals at different phenological phases. MB adsorption capacities were higher for biochar produced from young culms compared to those obtained from matures ones (i.e., GC: 628.66 vs. 507.79; BT: 537.45 vs. 477.53; PA: 477.52 vs. 462.82 mg/g), which had smaller cell wall widths leading to a lower percentage of biochar yield. The feedstock anatomical properties determined biochar characteristics which modulated adsorption capacities.

Asunto(s)

Bambusa , Carbón Orgánico , Azul de Metileno , Carbón Orgánico/química , Azul de Metileno/química , Adsorción , Bambusa/química , Purificación del Agua/métodos , Madera/química

RESUMEN

Microorganisms, such as fungi and bacteria, are crucial players in the production of enzymatic cocktails for biomass hydrolysis or the bioconversion of plant biomass into products with industrial relevance. The biotechnology industry can exploit lignocellulosic biomass for the production of high-value chemicals. The generation of biotechnological products from lignocellulosic feedstock presents several bottlenecks, including low efficiency of enzymatic hydrolysis, high cost of enzymes, and limitations on microbe metabolic performance. Genetic engineering offers a route for developing improved microbial strains for biotechnological applications in high-value product biosynthesis. Sugarcane bagasse, for example, is an agro-industrial waste that is abundantly produced in sugar and first-generation processing plants. Here, we review the potential conversion of its feedstock into relevant industrial products via microbial production and discuss the advances that have been made in improving strains for biotechnological applications.

Asunto(s)

Saccharum , Saccharum/química , Celulosa/química , Biotecnología , Biomasa , Hidrólisis , Lignina/química

RESUMEN

In this study, the possibility of increasing fermentation efficiency of Saccharomyces cerevisiae on sugarcane bagasse (a type of lignocellulosic waste) was analyzed. Sugarcane bagasse was subjected to hydrothermal and acidic pre-treatment. Next, the enzymatic hydrolysis of raw biomass and each pre treated biomass was performed using CellicCtec® enzymatic complex to obtain sugarcane hydrolysate, hydrothermal hydrolysate and acidic hydrolysate. Next, these were fermented by S. cerevisiae to check if the by-products of enzymatic hydrolysis, furfural and acetic acid had an inhibitory effect on fermentation efficiency. Next, each pre-treated biomass was subjected to detoxification involving activated charcoal. Each detoxified biomass was tested for fermentation efficiency. The lignocellulosic composition for sugarcane hydrolysate, hydrothermal hydrolysate and acidic hydrolysate, varied significantly, and were found to be, for cellulose 36.7%, 27.7% and 63.7% respectively; for hemicellulose 22.2%, 4.4% and 12% respectively; and for lignin 21.2%, 27.7% and 28.7% respectively. The presence of furfural and acetic acid had a strong influence on the fermentation efficiency of S. cerevisiae, and affected the consumption of sugars in each biomass by more than 90%. Further, we found that the detoxification process increased fermentation efficiency by 12.7% for the hydrothermal hydrolysate while for the acidic hydrolysate no significant difference was observed. This study showed that fermentation with greater efficiency is viable through the combined use of hydrothermal pre-treatment and detoxification. This combination of methods also causes less pollution as compared with the method involving acid pre-treatment due to the reduced number of effluents produced.(AU)

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Nesse trabalho avaliou-se a possibilidade de se aumentar a eficiência de fermentação de um hidrolisado de bagaço de cana submetido aos pré-tratamentos hidrotérmico (195 ºC, usando 200 rpm por 10 min) e ácido (0,5% (v/v) de ácido sulfúrico a 121ºC por 15 min) (carga de sólidos de 10% m/v). A hidrólise enzimática do material pré-tratado foi realizada utilizado o complexo enzimático CellicCtec® (60 FPU/gbiomassa seca, tampão citrato a 50 mM e pH 4,8) a 50ºC usando 150 rpm por 72h. Antes do processo de detoxificação, realizou-se um teste com a espécie de Saccharomyces cerevisiae para verificar se os compostos furfural (1 e 4g.L-1) e ácido acético (1 e 5% v/v) exerciam significativa inibição na espécie testada. O processo de detoxificação avaliou a concentração de carvão ativado (1, 3 e 5% m/v) e o tempo do processo (30, 45 e 60 min) a 30 ºC, 150 rpm por 24 h. A composição lignocelulosica da biomassa in natura e pré-tratada (hidrotérmico e ácido) foi para celulose (36,7, 27,7 e 63,7%), hemicelulose (22,2, 4,4 e 12%) e lignina (21,2, 27,7 e 28,7%), respectivamente e com rendimento mássico em torno de 60%. A presença de furfural e ácido acético exibiu forte influência na espécie considerada, chegando a prejudicar em mais de 90% o consumo de açúcares no meio. O processo de destoxificação aumentou 13% a eficiência de fermentação para o hidrolisado obtido hidrotermicamente, enquanto que para o ácido não houve diferença significativa. Obtendo assim uma fermentação com maior eficiência, tecnicamente viável e menos poluente.(AU)

Asunto(s)

Saccharomyces cerevisiae/química , Saccharum/fisiología , Fermentación/fisiología , Biomasa , Hidrólisis

RESUMEN

Biodiesel production from first-generation feedstock has shown a strong correlation with the increase in deforestation and the necessity of larger areas for land farming. Recent estimation from the European Federation for Transport and Environment evidenced that since the 2000s decade, an area equal to the Netherlands was deforested to supply global biodiesel demand, mainly originating from first-generation feedstock. Nevertheless, biodiesel is renewable, and it can be a greener source of energy than petroleum. A promising approach to make biodiesel independent from large areas of farming is to shift as much as possible the biodiesel production chain to second and third generations of feedstock. The second generation presents three main advantages, where it does not compete with the food industry, its commercial value is negligible, or none, and its usage as feedstock for biodiesel production reduces the overall waste disposal. In this manuscript, we present an oligomeric catalyst designed to be multi-functional for second-generation feedstock transesterification reactions, mainly focusing our efforts to optimize the conversion of tallow fat and sauteing oil to FAME and FAEE, applying our innovative catalyst. Named as Oligocat, our catalyst acts as a Brønsted-Lowry acid catalyst, providing protons to the reaction medium, and at the same time, with the course of the reaction, it sequesters glycerol molecules from the medium and changes its physical phase during the transesterification reaction. With this set of properties, Oligocat presents a pseudo-homogenous behavior, reducing the purification and separation steps of the biodiesel process production. Reaction conditions were optimized applying a 42 factorial planning. The output parameter evaluated was the conversion rate of triacylglycerol to mono alkyl esters, measured through gel permeation chromatography (GPC). After the optimization studies, a conversion yield of 96.7 (±1.9) wt% was achieved, which allows classifying the obtained mono alkyl esters as biodiesel by ASTM D6751 or EN 14214:2003. After applying the catalyst in three reaction cycles, Oligocat still presented a conversion rate above 96.5 wt% and as well an excellent recovery rate.

RESUMEN

Plant-based biofuels present a promising alternative to depleting non-renewable fuel resources. One of the benefits of biofuel is reduced environmental impact, including reduction in greenhouse gas emission which causes climate change. Sugarcane is one of the most important bioenergy crops. Sugarcane juice is used to produce table sugar and first-generation biofuel (e.g., bioethanol). Sugarcane bagasse is also a potential material for second-generation cellulosic biofuel production. Researchers worldwide are striving to improve sugarcane biomass yield and quality by a variety of means including biotechnological tools. This paper reviews the use of sugarcane as a feedstock for biofuel production, and gene manipulation tools and approaches, including RNAi and genome-editing tools, such as TALENs and CRISPR-Cas9, for improving its quality. The specific focus here is on CRISPR system because it is low cost, simple in design and versatile compared to other genome-editing tools. The advance of CRISPR-Cas9 technology has transformed plant research with its ability to precisely delete, insert or replace genes in recent years. Lignin is the primary material responsible for biomass recalcitrance in biofuel production. The use of genome editing technology to modify lignin composition and distribution in sugarcane cell wall has been realized. The current and potential applications of genome editing technology for sugarcane improvement are discussed. The advantages and limitations of utilizing RNAi and TALEN techniques in sugarcane improvement are discussed as well.

RESUMEN

Metal injection molding (MIM) has become an important manufacturing technology for biodegradable medical devices. As a biodegradable metal, pure iron is a promising biomaterial due to its mechanical properties and biocompatibility. In light of this, we performed the first study that manufactured and evaluated the in vitro and in vivo biocompatibility of samples of iron porous implants produced by MIM with a new eco-friendly feedstock from natural rubber (Hevea brasiliensis), a promisor binder that provides elastic property in the green parts. The iron samples were submitted to tests to determine density, microhardness, hardness, yield strength, and stretching. The biocompatibility of the samples was studied in vitro with adipose-derived mesenchymal stromal cells (ADSCs) and erythrocytes, and in vivo on a preclinical model with Wistar rats, testing the iron samples after subcutaneous implant. Results showed that the manufactured samples have adequate physical, and mechanical characteristics to biomedical devices and they are cytocompatible with ADSCs, hemocompatible and biocompatible with Wistars rats. Therefore, pure iron produced by MIM can be considered a promising material for biomedical applications.

Asunto(s)

Hevea , Hierro , Animales , Materiales Biocompatibles/farmacología , Ensayo de Materiales , Porosidad , Ratas , Ratas Wistar , Goma

RESUMEN

With the increase in global demand for biodiesel, first generation feedstock has drawn the attention of governmental institutions due to the correlation with large land farming areas. The second and third feedstock generations are greener feedstock sources, nevertheless, they require different catalytic conditions if compared with first generation feedstock. In this work, we present the synthesis and characterization of oligoesters matrices and their functionalization to act as a pseudo-homogeneous acid catalyst for biodiesel production, named Oligocat. The main advantage of Oligocat is given due to its reactional medium interaction. Initially, oligocat is a solid catalyst soluble in the alcoholic phase, acting as a homogeneous catalyst, providing better mass transfer of the catalytic groups to the reaction medium, and as the course of the reaction happens, Oligocat migrates to the glycerol phase, also providing the advantage of easy separation of the biodiesel. Oligocat was synthesized through polymerization of aromatic hydroxy acids, followed by a chemical functionalization applying the sulfonation technique. Characterization of the catalysts was carried out by infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). The synthesized oligomers presented 5357 g·mol-1 (Mw) and 3909 g·mol-1 (Mn), with a moderate thermal resistance of approximately 175 °C. By sulfonation reaction, it was possible to obtain a high content of sulphonic groups of nearly 70 mol%, which provided the catalytic activity to the oligomeric matrix. With the mentioned physical-chemical properties, Oligocat is chemically designed to convert second generation feedstock to biodiesel efficiently. Preliminary investigation using Oligocat for biodiesel production resulted in conversion rates higher than 96.5 wt.%.

RESUMEN

Production of butanol for fuel via the conventional Acetone-Butanol-Ethanol fermentation has been considered economically risky because of a potential oversupply of acetone. Alternatively, acetone is converted into isopropanol by specific solventogenic Clostridium species in the Isopropanol-Butanol-Ethanol (IBE) fermentation. This route, although less efficient, has been gaining attention because IBE mixtures are a potential fuel. The present work is dedicated to reviewing past and recent advances in microorganisms, feedstock, and fermentation equipment for IBE production. In our analysis we demonstrate the importance of novel engineered IBE-producing Clostridium strains and cell retention systems to decrease the staggering number of fermentation tanks required by IBE plants equipped with conventional technology. We also summarize the recent progress on recovery techniques integrated with fermentation, especially gas stripping. In addition, we assessed ongoing pilot-plant efforts that have been enabling IBE production from woody feedstock.

Asunto(s)

2-Propanol , Acetona , Butanoles , Etanol , Fermentación

RESUMEN

Solid-state fermentation (SSF) has been largely employed during the last three decades to produce different biomolecules of industrial interest, particularly enzymes. Through the use of agroindustrial wastes as SSF substrates, an economic process of lipases production can be achieved. In this chapter we describe a comprehensive SSF method for producing an economical preparation of Rhizomucor miehei lipase, employing sugarcane bagasse and used vegetal oil as substrates. To demonstrate the usefulness of the lipase produced by this method, we utilized directly the dried fermented solid, as a heterogeneous biocatalyst for the ethanolysis of different fats and oils. Final ethyl ester conversions (>90%, 24 h) were similar with those obtained using a commercial immobilized Rhizomucor miehei lipase at our best conditions. In this work we demonstrated that SSF is an easy and economical method for the production of lipases that can be used directly as heterogeneous biocatalysts for biodiesel production, employing low-cost feedstocks.

Asunto(s)

Bioingeniería , Fermentación , Lipasa/biosíntesis , Bioingeniería/instrumentación , Bioingeniería/métodos , Biocombustibles , Catálisis , Concentración de Iones de Hidrógeno , Hidrólisis , Cinesis , Lipasa/aislamiento & purificación , Temperatura

RESUMEN

The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental...

Asunto(s)

Gases de Efecto Invernadero , Calidad del Suelo , Saccharum/química , Uso de Residuos Sólidos , Productos Agrícolas , Reciclaje

RESUMEN

The use of crop residues as a bioenergy feedstock is considered a potential strategy to mitigate greenhouse gas (GHG) emissions. However, indiscriminate harvesting of crop residues can induce deleterious effects on soil functioning, plant growth and other ecosystem services. Here, we have summarized the information available in the literature to identify and discuss the main trade-offs and synergisms involved in crop residue management for bioenergy production. The data consistently showed that crop residue harvest and the consequent lower input of organic matter into the soil led to C storage depletions over time, reducing cycling, supply and availability of soil nutrients, directly affecting the soil biota. Although the biota regulates key functions in the soil, crop residue can also cause proliferation of some important agricultural pests. In addition, crop residues act as physical barriers that protect the soil against raindrop impact and temperature variations. Therefore, intensive crop residue harvest can cause soil structure degradation, leading to soil compaction and increased risks of erosion. With regard to GHG emissions, there is no consensus about the potential impact of management of crop residue harvest. In general, residue harvest decreases CO2 and N2O emissions from the decomposition process, but it has no significant effect on CH4 emissions. Plant growth responses to soil and microclimate changes due to crop residue harvest are site and crop specific. Adoption of the best management practices can mitigate the adverse impacts of crop residue harvest. Longterm experiments within strategic production regions are essential to understand and monitor the impact of integrated agricultural systems and propose customized solutions for sustainable crop residue management in each region or landscape. Furthermore, private and public investments/cooperations are necessary for a better understanding of the potential environmental...(AU)

Asunto(s)

Calidad del Suelo , Uso de Residuos Sólidos , Gases de Efecto Invernadero , Saccharum/química , Reciclaje , Productos Agrícolas

RESUMEN

Green waste (GW) is an important fraction of municipal solid waste (MSW). The composting of lignocellulosic GW is challenging due to its low decomposition rate. Recently, an increasing number of studies that include strategies to optimize GW composting appeared in the literature. This literature review focuses on the physicochemical quality of GW and on the effect of strategies used to improve the process and product quality. A systematic search was carried out, using keywords, and 447 papers published between 2002 and 2018 were identified. After a screening process, 41 papers addressing feedstock quality and 32 papers on optimization strategies were selected to be reviewed and analyzed in detail. The GW composition is highly variable due to the diversity of the source materials, the type of vegetation, and climatic conditions. This variability limits a strict categorization of the GW physicochemical characteristics. However, this research established that the predominant features of GW are a C/N ratio higher than 25, a deficit in important nutrients, namely nitrogen (0.5-1.5% db), phosphorous (0.1-0.2% db) and potassium (0.4-0.8% db) and a high content of recalcitrant organic compounds (e.g. lignin). The promising strategies to improve composting of GW were: i) GW particle size reduction (e.g. shredding and separation of GW fractions); ii) addition of energy amendments (e.g. non-refined sugar, phosphate rock, food waste, volatile ashes), bulking materials (e.g. biocarbon, wood chips), or microbial inoculum (e.g. fungal consortia); and iii) variations in operating parameters (aeration, temperature, and two-phase composting). These alternatives have successfully led to the reduction of process length and have managed to transform recalcitrant substances to a high-quality end-product.

Asunto(s)

Compostaje , Residuos Sólidos , Nitrógeno , Fósforo , Suelo

RESUMEN

Even though contamination by bacteria and wild yeasts are frequently observed during fuel ethanol fermentation, our knowledge regarding the effects of both contaminants together is very limited, especially considering that the must composition can vary from exclusively sugarcane juice to a mixture of molasses and juice, affecting the microbial development. Here we studied the effects of the feedstock (sugarcane juice and molasses) and the co-culture of Lactobacillus fermentum and a wild Saccharomyces cerevisiae strain (rough colony and pseudohyphae) in single and multiple-batch fermentation trials with an industrial strain of S. cerevisiae (PE-2) as starter yeast. The results indicate that in multiple-cycle batch system, the feedstock had a minor impact on the fermentation than in single-cycle batch system, however the rough yeast contamination was more harmful than the bacterial contamination in multiple-cycle batch fermentation. The inoculation of both contaminants did not potentiate the detrimental effect in any substrate. The residual sugar concentration in the fermented broth had a higher concentration of fructose than glucose for all fermentations, but in the presence of the rough yeast, the discrepancy between fructose and glucose concentrations were markedly higher, especially in molasses. The biggest problem associated with incomplete fermentation seemed to be the lower consumption rate of sugar and the reduced fructose preference of the rough yeast rather than the lower invertase activity. Lower ethanol production, acetate production and higher residual sugar concentration are characteristics strongly associated with the rough yeast strain and they were not potentiated with the inoculation of L. fermentum.

RESUMEN

Feruloylation of arabinoxylan (AX) in grass cell walls is a key determinant of recalcitrance to enzyme attack, making it a target for improvement of grass crops, and of interest in grass evolution. Definitive evidence on the genes responsible is lacking so we studied a candidate gene that we identified within the BAHD acyl-CoA transferase family. We used RNA interference (RNAi) silencing of orthologs in the model grasses Setaria viridis (SvBAHD01) and Brachypodium distachyon (BdBAHD01) and determined effects on AX feruloylation. Silencing of SvBAHD01 in Setaria resulted in a c. 60% decrease in AX feruloylation in stems consistently across four generations. Silencing of BdBAHD01 in Brachypodium stems decreased feruloylation much less, possibly due to higher expression of functionally redundant genes. Setaria SvBAHD01 RNAi plants showed: no decrease in total lignin, approximately doubled arabinose acylated by p-coumarate, changes in two-dimensional NMR spectra of unfractionated cell walls consistent with biochemical estimates, no effect on total biomass production and an increase in biomass saccharification efficiency of 40-60%. We provide the first strong evidence for a key role of the BAHD01 gene in AX feruloylation and demonstrate that it is a promising target for improvement of grass crops for biofuel, biorefining and animal nutrition applications.

Asunto(s)

Biomasa , Pared Celular/metabolismo , Coenzima A Transferasas/genética , Ácidos Cumáricos/metabolismo , Genes de Plantas , Setaria (Planta)/enzimología , Setaria (Planta)/genética , Supresión Genética , Ácidos/metabolismo , Brachypodium/genética , Metabolismo de los Hidratos de Carbono , Coenzima A Transferasas/metabolismo , Regulación de la Expresión Génica de las Plantas , Silenciador del Gen , Hidrólisis , Lignina/metabolismo , Espectroscopía de Resonancia Magnética , Tamaño de los Órganos , Filogenia , Tallos de la Planta/metabolismo , Plantas Modificadas Genéticamente , Semillas/anatomía & histología , Semillas/crecimiento & desarrollo , Transcriptoma/genética , Xilanos/metabolismo

RESUMEN

Non-renewable sources that will end with time are the largest part of world energy consumption, which emphasizes the necessity to develop renewable sources of energy. This necessity has created opportunities for the use of microalgae as a biofuel. The use of microalgae as a feedstock source for bioethanol production requires high yields of both biomass and carbohydrates. With mixotrophic cultures, wastewater can be used to culture algae. The aim of the study was to increase the carbohydrate content in the microalgae Spirulina with the additions of residues from the ultra and nanofiltration of whey protein. The nutrient deficit in the Zarrouk medium diluted to 20% and the addition of 2.5% of both residue types led to high carbohydrate productivity (60 mg L(-1) d(-1)). With these culture conditions, the increase in carbohydrate production in Spirulina indicated that the conditions were appropriate for use with microalgae as a feedstock in the production of bioethanol.

Asunto(s)

Biocombustibles , Biotecnología/métodos , Carbohidratos/biosíntesis , Microalgas/metabolismo , Spirulina/metabolismo , Biomasa , Biotecnología/instrumentación , Técnicas de Cultivo de Célula/métodos , Medios de Cultivo/química , Microalgas/química , Microalgas/citología , Spirulina/química , Spirulina/citología , Ultrafiltración , Aguas Residuales , Proteína de Suero de Leche/metabolismo

RESUMEN

Brazil has the world's largest ethanol production from sugarcane, but bacterial contamination decreases the ethanol yields. It was shown that the biocide DesinFix™ 135 can reduce the contamination without decreasing the yeasts' viability or negatively affecting the ethanol production.

Asunto(s)

Antibacterianos/farmacología , Biocombustibles , Etanol/metabolismo , Saccharum/metabolismo , Levaduras/metabolismo , Brasil , Fermentación

RESUMEN

Brazil has the world's largest ethanol production from sugarcane, but bacterial contamination decreases the ethanol yields. It was shown that the biocide DesinFixTM 135 can reduce the contamination without decreasing the yeasts' viability or negatively affecting the ethanol production.(AU)

Asunto(s)

Etanol/química , Biocombustibles , Fermentación , Antibacterianos

RESUMEN

Brazil has the world's largest ethanol production from sugarcane, but bacterial contamination decreases the ethanol yields. It was shown that the biocide DesinFixTM 135 can reduce the contamination without decreasing the yeasts' viability or negatively affecting the ethanol production.

Asunto(s)

Antibacterianos , Biocombustibles , Etanol/química , Fermentación

RESUMEN

In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26 percent lipids and via sonocatalysis stage of the methodology resulted in 60 percent of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).