Resumo A tendência de produção de biocombustíveis a partir de triacilgliceróis de microalgas está aumentando, porque esse substrato é uma boa alternativa sustentável e vantajosa ao combustível de petróleo e gás. No presente estudo, isolados de microalgas indígenas foram selecionados de amostras de água (n = 30) e solo (n = 30) coletadas em três distritos de Punjab, Paquistão, para avaliar seu potencial de produção de biocombustíveis. As amostras foram inoculadas em placas de meio BG – 11 agar por incubação em temperatura ambiente de 25°C proporcionando 1000 lux por 16h de ciclo claro seguido de 8h de escuro por 15 dias. As amostras de água foram ricas em microalgas e 65.33% de microalgas (49 isolados) foram isolados do distrito de Faisalabad. Com base na morfologia microscópica, isolados de microalgas (n = 180) foram selecionados e submetidos à detecção de lipídios por ensaio de coloração com vermelho do Nilo. Isolados positivos para vermelho do Nilo (n = 23) foram processados para caracterização bioquímica (lipídica, proteica e de carboidratos). O isolado AIN63 apresentou maior teor de lipídios (17.4%) conforme detectado pelo ensaio de microvanilina. O isolado de alga AIN128 apresentou os melhores teores de proteína (42.91%) detectados pelo ensaio de Bradford, e o isolado AIN172 apresentou maiores teores de carboidratos (73.83%), conforme detectado pelo ensaio de anthrone. Os isolados de algas selecionados também foram analisados por espectroscopia de infravermelho com transformada de Fourier (FTIR) para confirmação da análise de carboidratos, proteínas e lipídios. Essas algas nativas têm potencial para a produção de biocombustíveis in vitro a partir de resíduos agrícolas.

Abstract Trend of biofuel production from microalgal triacylglycerols is enhancing, because this substrate is a good sustainable and advantageous alternative to oil and gas fuel. In the present study, indigenous micro algal isolates were screened from water (n=30) and soil (n=30) samples collected from three districts of Punjab, Pakistan to evaluate their biofuel production potential. The samples were inoculated on BG – 11 agar medium plates by incubating at room temperature of 25°C providing 1000 lux for 16h light cycle followed by 8h of dark cycle for 15 d. Water samples were found to be rich in microalgae and 65.33% microalgae (49 isolates) were isolated from Faisalabad district. On the basis of microscopic morphology microalgal isolates (n=180) were selected and subjected to lipid detection by Nile red staining assay. Nile red positive isolates (n=23) were processed for biochemical (lipid, protein and carbohydrates) characterization. AIN63 isolate showed higher lipids (17.4%) content as detected by micro vanillin assay. Algal isolate AIN128 showed best protein contents (42.91%) detected by Bradford assay and AIN172 isolate showed higher carbohydrate contents (73.83%) as detected by anthrone assay. The selected algal isolates were also analyzed by Fourier transform infrared (FTIR) spectroscopy for confirmation of carbohydrate, protein and lipid analysis. These indigenous algae have the potential for in-vitro biofuel production from agricultural waste.

RESUMO: As microalgas são organismos cuja biomassa possui biomoléculas abundantes como carboidratos, lipídeos, proteínas, pigmentos, vitaminas, minerais e compostos antioxidantes, com inúmeras aplicações industriais com destaque para os segmentos de alimentos, nutricional, farmacológico, cosmético e de energia, na produção de biocombustíveis. Entretanto, o acesso de forma integra a essas biomoléculas pode ser dificultado pela rigidez estrutural de sua parede celular, sendo necessário a aplicação de um pré-tratamento que promova a lise celular. As diferentes técnicas de ruptura celular aplicáveis à biomassa microalgal descritas na literatura podem ser de natureza mecânica, com destaque para as técnicas de moagem em moinho de bolas e homogeneização à alta pressão (HAP) ou não mecânica (química, térmica e enzimática), cada uma com vantagens e desvantagens. Assim, o objetivo da presente revisão narrativa é descrever o uso de diferentes métodos para o rompimento de células de microalgas, com suas vantagens, desvantagens e seus desafios.

ABSTRACT: Microalgae are organisms whose biomass contains different biomolecules, such as carbohydrates, lipids, proteins, pigments, vitamins, minerals, and antioxidant compounds, with numerous industrial applications, highlighting the food, nutritional, cosmetic, pharmacological, and biofuel segments. However, access to these biomolecules in an integrated manner is often hampered due to the structural rigidity of their cell wall, requiring the application of a pre-treatment that promotes cell lysis. Various cell rupture techniques applied to microalgae biomass have been reported. These methods can be mechanical, especially ball milling techniques and high-pressure homogenization (HPH), or non-mechanical, such as chemical, thermal, and enzymatic procedures, each with advantages and disadvantages. Thus, this review addressed the different methods of cell disruption, listing their advantages and disadvantages, applications in cell biomass, and challenges.

Abstract Introduction: Moringa peregrina (Forssk.) Fiori seeds have good health promoting properties and considerable potential as a biofuel. However, cultivation is limited by variable seed quality. Objective: To study the effect of seed position in the pod and leaching treatment on germination and vegetative characteristics of seedlings. Materials and methods: The seeds numbered 1 to 6 (the position near the attached part to stem was No. 1). To study the effect of leaching on germination and the vegetative characteristics, seeds were exposed to running water for 0, 24 and 48 h. The experiment was performed in a completely randomized design as a factorial arrangement. Results and discussion: The position of the seed had a significant effect (P ≤ 0.05) on the variables, except for root fresh and dry weight and number of leaves; germination was higher for seeds in the middle position of the pod, which were also the heaviest (c. 0.73 g). There was a significant interaction between seed position and leaching, except for collar diameter and stem height. Leaching for 48 h increased germination to 88 %. This treatment produced the highest number of leaves (16.82) and the highest values for collar diameter (3.50 mm), dry weight of leaves (0.11 g), stem (0.08 g) and root (0.50 g), and root length (10.10 cm). The interaction of position and leaching was significant. Conclusions: The overall germination performance and seedling growth can be improved by immersing seeds from the middle pod position in leaching treatment for 48 h.

Resumen Introducción: Las semillas de Moringa peregrina (Forssk.) Fiori tienen propiedades beneficiosas para la salud y potencial considerable como biocombustible. No obstante, el cultivo está limitado por la calidad variable de las semillas. Objetivo: Investigar el efecto de la posición de la semilla en la vaina y el tratamiento de lixiviación sobre la germinación y características vegetativas de las plántulas. Materiales y métodos: Las semillas se numeraron del 1 al 6 (la posición cercana a la parte unida al tallo fue la número 1). Para investigar el efecto de lixiviación en la germinación y las características vegetativas, las semillas se expusieron a agua corriente durante 0, 24 y 48 h. El experimento consistió en un diseño completamente aleatorizado con arreglo factorial. Resultados y discusión: La posición de la semilla tuvo efecto significativo (P ≤ 0.05) en las variables, excepto en el peso fresco de las raíces y número de hojas; la germinación fue mayor en las semillas de las posiciones medias de la vaina, que fueron también las más pesadas (0.73 g). La lixiviación durante 48 h aumentó la germinación al 88 %. Este tratamiento produjo el mayor número de hojas (16.82) y los valores más altos de diámetro del cuello (3.50 mm), peso seco de hojas (0.11 g), tallo (0.08 g) y raíz (0.50 g), y longitud de raíz (10.10 cm). La interacción de la posición y la lixiviación fue significativa. Conclusiones: El rendimiento general de la germinación y el crecimiento de las plántulas pueden mejorarse mediante la inmersión de semillas de la posición media de la vaina en agua corriente durante 48 h.

ABSTRACT Microbial contamination of the wort during the fermentation process causes significant losses in ethanol production worldwide and creates a dependence of the industry on chemicals and antibiotics to control contamination. Therefore, this study used electron beam (e-beam) to disinfect wort from sugarcane (Saccharum officinarum L.) molasses and investigate the bioethanol fermentation. Four treatments (T0 – T3) were carried out using ionizing doses of radiation through the electron accelerator: 0 (control), 10, 20, and 40 kGy. Total mesophiles, total bacteria, sucrose, glucose, fructose, phenolics, flavonoids, hydroxymethylfurfural (5-HMF), and Furfural were measured. An alcoholic fermentation assay was performed after the irradiation process. The irradiated treatments showed no inversion of sugars and formation of the inhibitory by-products flavonoids, furfural and 5-HMF, except for the phenolic compounds. The lower dose tested (10 kGy) reduced more than 99.9 % of the total mesophiles and more than 99.99 % of the total bacteria in the substrate. In the fermentation, the irradiated worts presented similar (p > 0.05) yields (92, 93, and 94 %) and ethanol productivity levels (0.89, 0.88, and 0.87 g L–1 h–1, for T1, T2, and T3 respectively). However, all treatments presented higher yields and productivity (p < 0.05) when compared to the control (88 % and 0.85 g L–1 h–1), highlighting the possible use of e-beam in wort fermentation at a lower dose (10 kGy). This allows reduction in losses caused by microbial contamination, besides increasing fermentation yield and productivity with lower energy consumption.

Abstract Sugarcane is a crop of major importance used mainly for sugar and biofuel production, and many additional applications of its byproducts are being developed. Sugarcane cultivation is plagued by many insect pests and pathogens that reduce sugarcane yields overall. Recently emerging studies have shown complex multitrophic interactions in cultivated areas, such as the induction of sugarcane defense-related proteins by insect herbivory that function against fungal pathogens that commonly appear after mechanical damage. Fungi and viruses infecting sugarcane also modulate insect behavior, for example, by causing changes in volatile compounds responsible for insect attraction or repelling natural vector enemies via a mechanism that increases pathogen dissemination from infected plants to healthy ones. Interestingly, the fungus Fusarium verticillioides is capable of being vertically transmitted to insect offspring, ensuring its persistence in the field. Understanding multitrophic complexes is important to develop better strategies for controlling pathosystems affecting sugarcane and other important crops and highlights the importance of not only studying binary interactions but also adding as many variables as possible to effectively translate laboratory research to real-life conditions.

Abstract Lipids extracted from microalgae for biofuel production have drawn the attention of researchers. Various methods for quantification of neutral lipids, such as solvent extraction or gravimetric, require a large volume of sample and are time-consuming. In this work, Nile Red was employed to evaluate the lipid content in microalgae Scenedesmus sp. through 2D fluorescence spectroscopy using chemometric modeling with a selection of wavelength pairs reducing the variable numbers. Cultivation of microalgae for 10 days was performed. Samples were taken starting after the 5th day of cultivation. Microalgae samples were dried using an oven with tangential airflow and the conventional Bligh and Dyer method for lipid extraction was employed. Before the measurement of fluorescence, the samples were diluted in ethanol at 40°C for 10 minutes, and then Nile Red solution (10 µg/mL ethanol) was added. The results of lipid quantification using the proposed technique achieved mean absolute percentage error (MAPE) lower than 5% and correlation coefficients around 0.99 in the test phase. Linear models using four excitation-emission pairs of fluorescence were fitted and were selected based on Pure Spectral Chemometric Modelling (PSCM). The method for lipid quantification using predictive linear models and 2D fluorescence proved to be robust and fast (requiring less than 30 min) compared to the conventional gravimetric method (which takes at least 5 hours) to obtain comparable results.

ABSTRACT The growing interest in alternative fuels based on plant oils has led to the search for new plant species. Given this, during 2015–2020, oil from 12 varieties of oilseed radish was studied using standard research protocols. The average content of the dominant fatty acids in the oils studied was: [cis-9] oleic (C 18:1) 33.95% (Cv = 14.2%), [cis-9,12] linoleic (C 18:2) 16.20% (Cv = 20.8%), [cis-13] erucic (C 22:1) 15.18% (Cv = 17.9%), [cis-9, 12, 15] α-linolenic (C 18:3) 13.33% (Cv = 18.5%) and palmitic (C 16:0) 5.42% (Cv = 18.5%), with a monounsaturated fatty acid content of 59.69% and a ratio of polyunsaturated/monounsaturated fatty acids of 0.508. The studied varieties were ranked in the order of increasing suitability as a component of biofuels: ‘Zhuravka’ < ‘Raiduha’ < ‘Lybid’ < ‘Olga’ < ‘Iveya’ < ‘Ramonta’ < ‘Alpha’ < ‘Tambovchanka’ < ‘Fakel’ < ‘Snizhana’ < ‘Sabina’ < ‘Nika’. The technological suitability of oil from the ‘Zhuravka’ variety was confirmed based on analysis of its physicochemical parameters when subjected to polymerization (at 280 °C) and oxypolymerization (at 120 and 150 °C). Under these conditions the basic parameters of the oil varied within the technological limits that determine its suitability for thermodynamic combustion processes in systems with controlled pressure and temperature.

Abstract The aim was to investigate the differences between maize hybrids for their agronomic yield and their agro-energy potential. The study was conducted in Palotina and Assis Chateaubriand, Paraná, Brazil. The treatments were composed of 10 maize hybrids (DKB290 [non-GMO], DKB315, DKB340, DKB290, Formula, Defender, Status, 2B810, 30F53, BG7330), which were evaluated for grain moisture and yield, starch content, total soluble solids content, ethanol content in the juice and ethanol yield. The important factors for the result are related to grain yield and the quality of the harvested grains, and agronomic performance of these hybrids may differ according to each crop year. Hybrid 30F53 stood out positively for all variables. Hybrid DKB315 showed the highest ethanol yield and high grain yield, and insignificant grain quality was not enough to result in a decline in ethanol yield.

ABSTRACT The present work aimed to evaluate some technological characteristics of the wood of two commercial hybrid clones of Eucalyptus spp and two hybrid clones of Corymbia spp, implanted in three different planting spacings, at 24 months of age. Four trees per clone were sampled at each spacing to determine the following wood characteristics: basic density, gross calorific value, energy density and cellulose, hemicellulose, lignin, ash and carbon contents. There was a significant effect of the clone x spacing interaction for the basic density, energy density, lignin and cellulose contents of the wood. Eucalyptus showed the highest levels of lignin and cellulose, and hybrid clones of Corymbia the highest values of basic density and energy density of wood, with emphasis on clone C3, where the highest averages of the study were verified. For the levels of hemicelluloses and ash in the wood, the clone effect and spacing effect were observed. As for the carbon content and the gross calorific value in the wood, there was no significant effect, either from the clone, the spacing or the interaction of these two factors. The results show that there is variability in the characteristics between the genetic materials evaluated and in relation to the planting spacing tested. It should be noted that the choice of the best genetic material should be based on the technological characteristics of the wood, but also the forest productivity associated with good silviculture of the species should be evaluated.

RESUMO O presente trabalho teve como objetivo avaliar algumas características tecnológicas da madeira de dois clones híbridos comerciais de Eucalyptus spp e dois clones híbridos de Corymbia spp, implantados em três diferentes espaçamentos de plantio, aos 24 meses de idade. Quatro árvores por clone foram amostradas em cada espaçamento para determinar as seguintes características da madeira: densidade básica, poder calorífico superior, densidade energética e teores de celulose, hemiceluloses, lignina, cinzas e carbono. Observou-se efeito significativo da interação clone x espaçamento para a densidade básica, densidade energética, teores de lignina e de celulose da madeira. Os clones de Eucalyptus apresentaram os maiores teores de lignina e celulose, e coube aos clones híbridos de Corymbia os maiores valores de densidade básica e da densidade energética da madeira, com destaque para o clone C3, onde se verificou as maiores médias do estudo. Para os teores de hemiceluloses e cinzas na madeira, observou-se o efeito de clone e efeito de espaçamento. Quanto ao teor de carbono e ao poder calorífico superior na madeira, não houve efeito significativo, seja do clone, do espaçamento ou da interação desses dois fatores. Os resultados demonstram que há variabilidade das características entre os materiais genéticos avaliados e em relação aos espaçamentos de plantio testados. Cabe ressaltar que a escolha do melhor material genético deve ser baseada nas características tecnológicas da madeira, mas também deve ser avaliada a produtividade florestal associada à boa silvicultura da espécie.

Abstract Among the steps for the conversion of biomass into bioenergy, there is enzymatic hydrolysis. However, factors such as composition, formation of inhibitors, inhibition and enzymatic deactivation can affect the yield and productivity of this process. Lignocellulosic biomass is composed of cellulose, hemicellulose and lignin. However, lignin is organized in a complex and non-uniform way, promotes biomass recalcitrance, which repress the enzymatic attack on cellulose to be converted into glucose, and, consequently, the production of biofuel. Thus, a challenge in enzymatic hydrolysis is to model the reaction behavior. In this context, this study aims to evaluate the performance in enzymatic hydrolysis for the conversion of cellulose present in sugarcane bagasse into glucose. Therefore, modeling and optimization will be proposed to produce high glucose concentration rates. Therefore, a previously developed study will be used, in which the authors proposed a kinetic model for the hydrolysis step. However, as a differential to what has been proposed, the calculation will be carried out evaluating the evaporation, in order to maximize the response to the glucose concentration. Thus, considering evaporation and optimized kinetic parameters, it was possible to obtain high rates of glucose concentration at 204.23 $g.L^{-1

ABSTRACT Corn, Zea mays (L.), is one of the most expressive crops in Brazil, due to its wide-ranging uses as animal feeding, biofuel production or used for human consumption. However, there is a huge gap between the actual yield and the natural yield potential of the crop, due to insects’ attack. Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae) is a key corn pest in seed producing regions, due to its attack on corn ears. Plant resistance is a valuable tool for Integrated Pest Management systems and may maintain insect populations at a level that is below an economic or damage threshold. This study aimed to evaluate the biological performance of L. zonatus in different corn genotypes, under laboratory conditions, searching for possible characterization of antibiosis/antixenosis. To achieve this goal, ten nymphs (1st instar) were transferred to polyvinylchloride (PVC) ring containing a corn ear (R6) of each genotype. Each ring corresponded to one replicate, for a total of five replicates per genotype in a completely randomized design. The parameters assessed included the duration of each instar, nymphal period, nymphal survival (%), percentage of mortality of each nymphal stage, adult longevity, and adult weight. The results demonstrate that XB 8018 Bt, 30F53, IAC Airan, XB 8030 and 30F53 YHR genotypes reduced the mean survival and caused high mortality of L. zonatus nymphs at the second instar (above 75.00%) indicating the occurrence of antibiosis/antixenosis. The higher mortality rates were observed at the second nymphal instar.

ABSTRACT Elephant grass stands out among lignocellulosic biomass plants utilized for second-generation biofuel production due to several advantageous characteristics compared to other raw materials. Its short production cycle and ability to thrive in adverse soil and climate conditions contribute to its appeal. Additionally, breeders seek genotypes with high productivity potential and adaptability to various favorable cultivation environments. This study aimed to estimate genetic parameters, predict genetic values using mixed models (REML/BLUP), and evaluate stability and adaptability for energy biomass production in elephant grass genotypes. The experiment was conducted in Campos dos Goytacazes, RJ, Brazil, utilizing a two-replicate experimental block design that included 40 elephant grass genotypes. Four harvest assessments were performed between 2016 and 2019. Genetic parameter estimation and selection of superior genotypes based on genetic value using the REML/BLUP procedure were performed using Selegen software. Stability and adaptability analyses were obtained through the harmonic mean of genotypic values (HMGV), enabling the identification of stable and highly productive genotypes. Genotypes 17, 18, 32, 16, 36, 6, 15, 31, and 34 exhibited outstanding performance in terms of HMGV, indicating enhanced stability, adaptability, and simultaneous productivity, thus ensuring robustness in cultivation. These selected genotypes hold potential for future breeding programs aimed at improving elephant grass yield for biomass production.

Abstract Objectives: This article aims to analyze the economic effects of bioethanol policies in Mexico, where there have been several attempts to introduce biofuels into the market but so far, no success. Methodology: Technically, an endogenous-price mathematical programming model is developed emphasizing the agricultural and fuel sectors, which are embedded in a multi-region, multi-product, spatial partial equilibrium model. Bioethanol can be produced both from a dedicated crop and from agroindustrial residues. Three policy alternatives are considered as well as a base case in which, as now, liquid fuels are all derived from fossil sources. The first alternative consists of subsidies to biofuel producers, the second of blending mandates and the third of both combined. Results: Results show some losses for fuel and agricultural consumers, that are not offset by both ethanol producer and environmental gains. Limitations and implications: The base year data should be more recent, but it is very difficult to gather all this amount of information for a more recent year. Like any partial equilibrium model, the analysis ignores the effects outside the markets included in the model. Originality and value: Model developed for this research, and it is the first economic study on bioethanol in Mexico that reaches such a detailed analysis. Conclusions: This research suggests that it is possible to develop a bioethanol market in Mexico, but some compensating redistribution among economic groups may be needed if these policies are to be seen as politically sustainable.

Resumen Objetivo: Analizar los efectos económicos de las políticas de bioetanol en México, donde ha habido varios intentos de introducir biocombustibles en el mercado sin éxito. Metodología: Se desarrolla un modelo de programación matemática de precios endógenos con énfasis en los sectores agrícola y de combustibles, que están integrados en un modelo de equilibrio parcial espacial, multirregional y multiproducto. El bioetanol se puede producir a partir de un cultivo específico y de residuos agroindustriales. Se consideran tres alternativas de política, así como un caso base en el que, como ahora, los combustibles líquidos se derivan todos de fuentes fósiles. La primera alternativa consiste en subsidios a los productores de biocombustibles, la segunda en mandatos de mezcla y la tercera en una combinación de ambas políticas. Resultados: Los resultados muestran algunas pérdidas para los consumidores de combustibles y productos agrícolas, que no se compensan con las ganancias ambientales y de los productores de etanol. Limitaciones e implicaciones: Los datos del año base deberían ser más recientes, pero es muy difícil reunir toda esta cantidad de información para un año más reciente. Como cualquier modelo de equilibrio parcial, el análisis ignora los efectos fuera de los mercados incluidos en el modelo. Originalidad y valor: Modelo desarrollado para esta investigación y es el primer estudio económico sobre el bioetanol en México que llega a un análisis tan detallado. Conclusiones: Es posible desarrollar un mercado de bioetanol en México, pero se requiere alguna redistribución para compensar a los grupos que pierden si se quiere tener estas políticas sostenibles en el largo plazo.

Resumen El objetivo del presente estudio es obtener los valores de poderes caloríficos y las propiedades cualitativas de pellets elaborados a partir de cuatro subproductos agrícolas en co-combustión con carbón y sin co-combustión. Esto se realizó con la finalidad de resaltar la importancia de la biomasa en co-combustión como fuente de energía alternativa. Las muestras estudiadas son: molienda gruesa de semillas de sorgo, colza, soja, semillas de girasol y sus mezclas con carbón. Se calcularon los siguientes parámetros: poderes caloríficos superiores, densidades aparentes, densidades energéticas, índice de valor del combustible, contenido de nitrógeno y azufre. Se estableció la composición proximal definida por ASTM: humedad, ceniza, materia volátil y carbón fijo. El contenido de humedad y cenizas de los subproductos agrícolas estudiados se identifican como los principales factores de influencia calorífica. Los resultados obtenidos vienen a confirmar la capacidad de la biomasa de co-combustión para ser utilizada como combustible. Como resultado de los datos experimentales, la biomasa co-quemada de residuos agrícolas es un buen recurso como biocombustible en forma de gránulos. Entre las muestras estudiadas, la molienda de semillas de girasol cocida presenta el valor calorífico más alto, el contenido de carbono fijo y el índice de valor de combustible más altos, por lo que es una buena alternativa al combustible fósil para producir energía y reducir la contaminación del aire doméstico y la cantidad de madera necesaria.

Abstract The aim of the present study is obtaining the calorific values and the qualitative properties of the pellets made from four agricultural by-products co-fired with coal and non-cofired, in order to highlight the importance of co-fired biomass as alternative energy source. The studied samples are coarse ground grist of sorghum seeds, rape seeds, soyabean, sunflower seeds and their mixture with coal. The following parameters are calculated: higher heating values, bulk densities, energy densities, fuel value index, nitrogen, and sulphur content. The proximate composition as defined by ASTM was established: moisture, ash, volatile matter, and fixed carbon. The moisture and ash content of the studied agricultural by-products are identified as the main factors of calorific influence. The obtained results come to confirm the ability of co-fired biomass to be used as fuel. As resulted from the experimental data, the co-fired biomass of agricultural residues are good resources as biofuel in the form of pellets. Among the studied samples, co-fired sunflower seeds grist presents the highest heating value, highest fixed carbon content and fuel value index, thus being a good alternative to fossil fuel in order to produce energy and reduce the domestic air pollution and the amount of wood needed.

RESUMO O estudo visa quantificar os custos de produção das culturas de milho e sorgo em condições de sequeiro e irrigado para a geração de etanol, e avaliar a viabilidade econômica em diferentes cenários de preço de comercialização. Foram realizados dois experimentos nos anos de 2019/2020 e 2020/2021, em área experimental da Universidade Federal de Santa Maria, Santa Maria, RS. O delineamento experimental foi em faixas, com blocos ao acaso e quatro repetições. Foram avaliadas três lâminas de irrigação: 0, 50 e 100% da evapotranspiração de referência (ETo) como o primeiro fator, e duas cultivares de milho e uma de sorgo granífero como o segundo fator, sendo utilizados 45 cenários. O uso da irrigação plena (100% de ETo) reduz os custos de produção do litro de etanol em 15 e 17,89% e aumenta a produção de etanol em 44,18 e 48,25% para as culturas de milho e sorgo, respectivamente. Para o preço de mercado de R$ 2,00 L-1, o sorgo granífero não apresenta bom desempenho, com valor presente líquido (NPV) e taxa interna de retorno (IRR) negativos. O preço de venda de R$ 4,00 L-1 e irrigação plena é o melhor cenário econômico, com valores de NPV de R$ 90.356,93, IRR de 33,83%, relação benefício/custo (B/C) de 2,28, índice de rentabilidade (PI) de 3,99 e payback de três anos. O milho é economicamente viável para a produção de etanol em todos os cenários, sendo a irrigação plena e preço de comercialização de R$ 4,00 L-1, o que apresentou o melhor cenário econômico, com valores médios para o NPV de R$ 204.381,68, IRR de 63,35%, B/C de 2,96, IR 8,67 e payback de 1,58 anos, entre as cultivares.

ABSTRACT The study aims to quantify the production costs of maize and sorghum crops under rainfed and irrigated conditions for the generation of ethanol and to evaluate the economic feasibility in different scenarios of marketing price. Two experiments were carried out in the years 2019/2020 and 2020/2021, in an experimental area at the Federal University of Santa Maria, Santa Maria, RS, Brazil. The experiment was in strip plots, in a randomized block design and four replicates. Three irrigation depths, 0, 50 and 100% of the reference evapotranspiration (ETo), as first factor, and two maize cultivars and one grain sorghum cultivar as second factor, using 45 scenarios. The use of full irrigation (100% of ETo) reduces the production costs of the liter of ethanol by 15 and 17.89% and increases ethanol production by 44.18 and 48.25% for maize and grain sorghum crops, respectively. For the market price of R$ 2.00 L-1, the grain sorghum does not show good performance, with negative net present value (NPV) and internal rate of return (IRR). The sale price of R$ 4.00 L-1 and full irrigation is the best economic scenario, with values of NPV of R$ 90,356.93, IRR of 33.83%, benefit/cost ratio (B/C) of 2.28, profitability index (PI) of 3.99 and payback of three years. Maize is economically viable for ethanol production in all scenarios. Full irrigation and market price of R$ 4.00 L-1 represent the best economic scenario, with mean values for NPV of R$ 204,381.68, IRR of 63.35%, B/C of 2.96, PI of 8.67 and payback of 1.58 years, among the cultivars.