Bioethanol Production Process Research Articles

Assessing the Application of Near-Infrared Spectroscopy to Determine Saccharification Efficiency of Corn Biomass

AbstractNowadays, in the bioethanol production process, improving the simplicity and yield of cell wall saccharification procedure represent the main technical hurdles to overcome. This work evaluated the application of a rapid and cost-effective technology such as near -infrared spectroscopy (NIRS) for easily predict saccharification efficiency from corn stover biomass. Calibration process focussing on the number of samples and the genetic background of the maize inbred lines were tested; while Modified Partial Least Squares Regression (MPLS) and Multiple Linear Regression (MLR) were assessed in predictions. The predictive capacity of the NIRS models was mainly determined by the coefficient of determination (r2ev) and the index of prediction to deviation (RPDev) in external validation. Overall, we could check a better efficiency of the NIRS calibration process for saccharification using larger number of observations (1500 sample set) and genetic backgrounds; while MPLS regression provided better prediction statistics (r2ev = 0.80; RPDev = 2.21) compared to MLR (r2ev = 0.68; RPDev = 1.75). These results indicate that NIRS could be successfully implemented as a large-phenotyping tool in order to test the saccharification potential of corn biomass.

Renewable Energy Potential: Second-Generation Biomass as Feedstock for Bioethanol Production.

Biofuels are clean and renewable energy resources gaining increased attention as a potential replacement for non-renewable petroleum-based fuels. They are derived from biomass that could either be animal-based or belong to any of the three generations of plant biomass (agricultural crops, lignocellulosic materials, or algae). Over 130 studies including experimental research, case studies, literature reviews, and website publications related to bioethanol production were evaluated; different methods and techniques have been tested by scientists and researchers in this field, and the most optimal conditions have been adopted for the generation of biofuels from biomass. This has ultimately led to a subsequent scale-up of procedures and the establishment of pilot, demo, and large-scale plants/biorefineries in some regions of the world. Nevertheless, there are still challenges associated with the production of bioethanol from lignocellulosic biomass, such as recalcitrance of the cell wall, multiple pretreatment steps, prolonged hydrolysis time, degradation product formation, cost, etc., which have impeded the implementation of its large-scale production, which needs to be addressed. This review gives an overview of biomass and bioenergy, the structure and composition of lignocellulosic biomass, biofuel classification, bioethanol as an energy source, bioethanol production processes, different pretreatment and hydrolysis techniques, inhibitory product formation, fermentation strategies/process, the microorganisms used for fermentation, distillation, legislation in support of advanced biofuel, and industrial projects on advanced bioethanol. The ultimate objective is still to find the best conditions and technology possible to sustainably and inexpensively produce a high bioethanol yield.

An experimental and modeling approach to describe the deactivation of cellulases at the air-liquid interface.

Understanding the reaction mechanisms involved in the enzymatic hydrolysis of cellulose is important because it is kinetically the most limiting step of the bioethanol production process. The present work focuses on the enzymatic deactivation at the air-liquid interface, which is one of the aspects contributing to this global deactivation. This phenomenon has already been experimentally proven, but this is the first time that a model has been proposed to describe it. Experiments were performed by incubating Celluclast cocktail solutions on an orbital stirring system at different enzyme concentrations and different surface-to-volume ratios. A 5-day follow-up was carried out by measuring the global FPase activity of cellulases for each condition tested. The activity loss was proven to depend on both the air-liquid surface area and the enzyme concentration. Both observations suggest that the loss of activity takes place at the air-liquid surface, the total amount of enzymes varying with volume or enzyme concentration. Furthermore, tests performed using five individual enzymes purified from aTrichoderma reesei cocktail showed that the only cellulase that is deactivated at the air-liquid interface is cellobiohydrolaseII. From the experimental data collected by varying the initial enzyme concentration and the ratio surface to volume, it was possible to develop, for the first time, a model that describes the loss of activity at the air-liquid interface for this configuration.

Multienzyme production by Bacillus velezensis strains isolated from fruit residues in submerged fermentation using triticale and sugarcane bagasse in the cultivation media

The production of multienzymes complex that could act in different raw materials is needed to improve the bioethanol production process. We isolated bacteria from vegetable residues, identified as Bacillus velezensis (UPF-B1 and UPF-B2), which were able to simultaneously produce amylolytic and cellulolytic enzymes. The enzyme complex was produced by submerged fermentation in a media containing whole-grain triticale flour and sugarcane bagasse at pH 5.5 without supplementation with micronutrient solutions, reducing the media's costs. The combined use of raw materials (triticale and sugarcane bagasse) led to higher enzymatic activities, which is important given the need for the availability of raw materials for the industrial operation of enzyme and bioethanol production plants. The enzymes produced by UPF-B1 showed their optimum at pH 5.0–5.5 and 40 ºC, and those produced by UPF-B2 at pH 5.0–5.5 and 30–50 ºC. The multienzyme complex produced by the strain UPF-B2 allows the hydrolysis in mild temperatures, near to those of fermentation processes, avoiding the need for thermophilic yeasts in the fermentation step, being a desirable option to be used in simultaneous saccharification and fermentation processes of bioethanol production.

Modelling and dynamic simulation to produce fermentable sugars from lignocellulosic substrates through dilute acid hydrolysis

AbstractThis research paper presents a comprehensive investigation aimed at enhancing the 2G bioethanol production process through the implementation of a dynamic process simulator. The simulator, developed using the Julia programming language, enables the prediction of acid hydrolysis behaviour by manipulating critical variables, including liquid–solid ratio (LSR), acid concentration (CA), and processing time (t). Through meticulous simulations and subsequent experimental validation, optimal operating conditions were revealed, with an H2SO4 concentration of 2% v/v, a LSR of 4% v/w, and 60‐min processing time at 121.1°C. This configuration led to remarkable outcomes, including a xylose concentration of 47.45 g L−1 and an 87.4% hemicellulose removal percentage. Moreover, the simulator unveiled the adverse influence of low LSR values on xylose production and the generation of degradation products. The recalibration of kinetic parameters, guided by experimental data, further fine‐tuned the simulator's predictive accuracy. Overall, this study underscores the potential of the simulator in optimizing various raw materials and presents a promising avenue for advancing 2G bioethanol industry practices.

Low-temperature methanation of fermentation gas with Ni-based catalysts in a multicomponent system

A large amount of greenhouse gases, such as carbon dioxide and methane, are released during the production process of bioethanol and biogas. Converting CO2 into methane is a promising way of capturing CO2 and generating high-value gas. At present, CO2 methanation technology is still in the early stage. It requires high temperature (300–400 ℃) and pressure (> 1 MPa), leading to high cost and energy consumption. In this study, a new catalyst, Ni–Fe/Al–Ti, was developed. Compared with the activity of the common Ni/Al2O3 catalyst, that of the new catalyst was increased by 1/3, and its activation temperature was reduced by 100℃. The selectivity of methane was increased to 99%. In the experiment using simulated fermentation gas, the catalyst showed good catalytic activity and durability at a low temperature and atmospheric pressure. Based on the characterization of catalysts and the study of reaction mechanisms, this article innovatively proposed a Ni–Fe/Al–Ti quaternary catalytic system. Catalytic process was realized through the synergism of Al–Ti composite support and Ni–Fe promotion. The oxygen vacancies on the surface of the composite carrier and the higher activity metals and alloys promoted by Fe accelerate the capture and reduction of CO2. Compared with the existing catalysts, the new Ni–Fe/Al–Ti catalyst can significantly improve the methanation efficiency and has great practical application potential.

Modeling and simulation of an integrated bioethanol-hydrogen production process

Hydrogen (H2) production from renewable feedstocks such as bioethanol represents one of the sustainable and environmentally benign methods of making the proposed utilization of H2 as energy carrier of the future a reality. However, successful implementation of this technology depends on several factors which include understanding of the technicality, as well as process design and modelling. Generally, this area of research has not received adequate attentions. In this article, an integrated process for producing H2 through starch hydrolysis, fermentation, and ethanol steam reforming (ESTR) process has been proposed. Enzymatic hydrolysis of starch was performed to obtain the fermentable sugar (hydrolysate). In addition, batch fermentation experiments were carried out using a laboratory scale fermenter with yeast (Saccharomyces cerevisiae) culture adapted for anaerobic conversion of the hydrolysate to bioethanol. Subsequently, kinetic data obtained from these experiments was employed to guide thermodynamic modeling of fermentation process which was coupled with the ESTR model and was implemented in the Aspen HYSYS simulator. The results ultimately revealed pertinent information which could find applications in the implementation of the proposed integrated process for bioethanol and H2 production.

Assessment of the Benefits of Supplementation of Wort from Sugarcane with Inorganic Nutrients in the Bioethanol Production Process

Assessment of the Benefits of Supplementation of Wort from Sugarcane with Inorganic Nutrients in the Bioethanol Production Process

Aflatoxin Decontamination in Maize Steep Liquor Obtained from Bioethanol Production Using Laccases from Species within the Basidiomycota Phylum.

Maize (Zea mays L.) is an important crop in Argentina. Aspergillus section Flavi can infect this crop at the pre-harvest stage, and the harvested grains can be contaminated with aflatoxins (AFs). During the production of bioethanol from maize, AF levels can increase up to three times in the final co-products, known as, dry and wet distiller's grain with solubles (DDGS and WDGS), intended for animal feed. Fungal enzymes like laccases can be a useful tool for reducing AF contamination in the co-products obtained from this process. The aim of the present study was to evaluate the ability of laccase enzymes included in enzymatic extracts (EE) produced by different species in the Basidiomycota phylum to reduce AF (AFB1 and AFB2) accumulation under the conditions of in vitro assays. Four laccase activities (5, 10, 15, and 20 U/mL) exerted by nine isolates were evaluated in the absence and presence of vanillic acid (VA), serving as a laccase redox mediator for the degradation of total AFs. The enzymatic stability in maize steep liquor (MSL) was confirmed after a 60 h incubation period. The most effective EE in terms of reducing AF content in the buffer was selected for an additional assay carried out under the same conditions using maize steep liquor obtained after the saccharification stage during the bioethanol production process. The highest degradation percentages were observed at 20 U/mL of laccase enzymatic activity and 1 mM of VA, corresponding to 26% for AFB1 and 26.6% for AFB2. The present study provides valuable data for the development of an efficient tool based on fungal laccases for preventing AF accumulation in the co-products of bioethanol produced from maize used for animal feed.

Computational Fluid Dynamics Modeling of Fermentation Reactions in Bioethanol Fermentor: A Review

Bioethanol is a renewable energy source that can replace fossil fuels. The advantages in terms of economy and its impact on the environment make bioethanol was chosen as a biofuel. Bioethanol can be produced from various types of biomasses with the help of microorganisms, namely yeast, for the fermentation process. In manufacturing, factors including temperature, concentration, pH, fermentation time, and stirring speed influence the fermentation process. Computational Fluid dynamics (CFD) package can be applied to observe the procedures in a fermenter. CFD simulates fluid movement, energy transport, chemical reactions, and other phenomena with the aim of clarifying their impact on the overall effectiveness of bioethanol production. In this journal, a review of the fermentation process with CFD modeling was made to look at the parameters and phenomena during the bioethanol production process. The analysis commences with an examination of the processes involved in bioethanol production and underscores the crucial role of fermentation in transforming renewable resources into bioethanol. Subsequently, it delves into the foundational principles of CFD and how they are incorporated into the modeling of bioethanol fermenters. Furthermore, the review highlights key advancements and innovations in CFD modeling techniques, such as multiphase models, turbulence modeling, and coupled simulations, aiming to capture the intricate interplay of physical and biological phenomena within fermentors. Insights into the impact of operating conditions, reactor design, and microbial behavior on bioethanol yield and quality are discussed, providing a comprehensive understanding of the complex system dynamics.

First- and second-generation integrated process for bioethanol production: Fermentation of molasses diluted with hemicellulose hydrolysate by recombinant Saccharomyces cerevisiae.

The integration of first- (1G) and second-generation (2G) ethanol production by adding sugarcane juice or molasses to lignocellulosic hydrolysates offers the possibility to overcome the problem of inhibitors (acetic acid, furfural, hydroxymethylfurfural and phenolic compounds), and add nutrients (such as salts, sugars and nitrogen sources) to the fermentation medium, allowing the production of higher ethanol titers. In this work, an 1G2G production process was developed with hemicellulosic hydrolysate (HH) from a diluted sulfuric acid pretreatment of sugarcane bagasse and sugarcane molasses. The industrial Saccharomyces cerevisiae CAT-1 was genetically modified for xylose consumption and used for co-fermentation of sucrose, fructose, glucose, and xylose. The fed-batch fermentation with high cell density that mimics an industrial fermentation was performed at bench scale fermenter, achieved high volumetric ethanol productivity of 1.59 g L-1 h-1, 0.39 g g-1 of ethanol yield, and 44.5 g L-1 ethanol titer, and shown that the yeast was able to consume all the sugars present in must simultaneously. With the results, it was possible to establish a mass balance for the global process: from pretreatment to the co-fermentation of molasses and HH, and it was possible to establish an effective integrated process (1G2G) with sugarcane molasses and HH co-fermentation employing a recombinant yeast.

PEMBUATAN BIOETANOL DARI BATANG KELAPA SAWIT (Elais Guineensis Jacq.) MELALUI PROSES PRETREATMENT MENGGUNAKAN H2SO4 DAN FERMENTASI MENGGUNAKAN RAGI ROTI (Saccharomyces cerevisiae)

Unproductive oil palm stems can produce Umbut which is the raw material for bioethanol production. In general, the production process of bioethanol from lignocellulosic materials includes oil palm stalks. The bioethanol production process goes through several stages of physical, chemical or biological pretreatment, polymer saccharification, sugar fermentation, and ethanol separation and purification. This study aims to determine the production of bioethanol from oil palm stems (Elaeis Guineensis Jacq) through a pretreatment process using H2S04 and fermentation using baker's yeast (Saccharomyces cerevisiae). The method used in this study was a Completely Randomized Design (CRD) Non Factorial with 3 treatment levels and 1 control, and 3 repetitions (Triplo) with a total sample of 12 samples. The resulting bioethanol is then tested (moisture content, yield, and pH). The resulting data were analyzed using ANOVA and Duncan's test. Based on the results of this study, the best treatment was found in the H0 treatment with a yield of 34.5%, 1.52% moisture content and 5,6 % pH

Bambusa tulda: A potential feedstock for bioethanol and its blending effects on the performance of spark ignition engine

Alternatives to conventional fuel sources must be investigated due to strict regulatory requirements and the depletion of fossil fuel supplies. As a result, of better transportation and population growth, the requirement for energy is increasing daily. Bioethanol may be used successfully to replace both gasoline and spark ignition engine diesel. Most nations blend 10% bioethanol with gasoline in automobiles. Several nations, notably India, have announced that they will soon begin blending 20% bioethanol with gasoline. Bambusa Tulda is used as a raw material for the extraction of bioethanol, which is a type of Indian bamboo. This study covers both the ethanol extraction from bamboo and the effects of various mixtures on spark-ignited engine performance. Four separate blends were developed on a volumetric basis at varying engine speeds, and the wide-open throttle was utilized to evaluate the performance and emissions of each mix with a constant compression ratio of 10:1. When bioethanol was enhanced, combustion efficiency, indicated power, engine power, mechanical efficiency, and volumetric efficiency all increased. Hydrocarbon, carbon monoxide, and carbon dioxide emissions decreased, while nitrogen oxide emissions increased. The engine performance of BE 15 was found to be the greatest among all the gasoline blends tested. According to this study, when nitrogen oxide emission control methods are applied, bamboo may be used as a feedstock for the manufacture of second-generation bioethanol. This invention offers a bioethanol production process that is good for environmental sustainability.

Catalytic hydrolysis of agar using magnetic nanoparticles: optimization and characterization

BackgroundAgar is used as a gelling agent that possesses a variety of biological properties; it consists of the polysaccharides agarose and porphyrin. In addition, the monomeric sugars generated after agar hydrolysis can be functionalized for use in biorefineries and biofuel production. The main objective of this study was to develop a sustainable agar hydrolysis process for bioethanol production using nanotechnology. Peroxidase-mimicking Fe3O4-MNPs were applied for agar degradation to generate agar hydrolysate-soluble fractions amenable to Saccharomyces cerevisiae and Escherichia coli during fermentation.ResultsFe3O4-MNP-treated (Fe3O4-MNPs, 1 g/L) agar exhibited 0.903 g/L of reducing sugar, which was 21-fold higher than that of the control (without Fe3O4-MNP-treated). Approximately 0.0181% and 0.0042% of ethanol from 1% of agar was achieved using Saccharomyces cerevisiae and Escherichia coli, respectively, after process optimization. Furthermore, different analytical techniques (FTIR, SEM, TEM, EDS, XRD, and TGA) were applied to validate the efficiency of Fe3O4-MNPs in agar degradation.ConclusionsTo the best of our knowledge, Fe3O4-MNP-treated agar degradation for bioethanol production through process optimization is a simpler, easier, and novel method for commercialization.

Potential Development and Economic Analysis of Bioethanol Fabrication Design from Oil Palm Biomass with Ionic Liquid Choline Acetate Using SuperPro Designer (SPD) Software

The increasing use of energy causes the availability of energy, especially in Indonesia, to be depleted. This condition encourages humans to develop renewable energy sources, one of which is bioethanol, with the availability of abundant raw materials in nature. However, the development of bioethanol is still ineffective because it requires a long time and has high costs. Therefore, a design for bioethanol fabrication from oil palm plantation products with ionic liquid pretreatment using SuperPro Designer (SPD) software was developed. The bioethanol production process was simulated through three stages: pretreatment, enzymatic saccharification, and fermentation. Pretreatment was carried out using the ionic liquid Choline Acetate, after which the results of saccharification and fermentation were analyzed. The results of saccharification showed that around 138 g/L of palm oil was converted into sugar for fermentation. The overall result of the simulation system is that the fermentation process for 12 hours produced 92 g/L ethanol or 96% of the theoretical yield. Meanwhile, ethanol production through fabrication for energy can reduce ethanol prices by 30% from their initial price. This ethanol fabrication design is very supportive of optimizing biomass into bioethanol. Therefore, this design can be used as a recommendation for economical bioethanol production to obtain optimal results in bioethanol production.

Characterization of Three Sugarcane Varieties as Agro-Residue for Bioenergy Use in the Ecuadorian Andes

There is a growing trend toward the use of renewable sources to produce clean energy and mitigate the effects of climate change. Second-generation lignocellulose biomasses, such as agro-residues, comprise a potential energy source as a byproduct of agriculture. Ecuador has optimal climate conditions that allow for the cultivation of different types of crops. This makes agriculture a relevant economic activity in the country; however, the residues obtained from agriculture have not been investigated for the establishment of a bioenergy industry. This study evaluated the potential of three varieties of sugarcane bagasse, named PR 980, CC 85-92, and CB 40-59, for bioenergy production in the Ecuadorian Andes. The bagasse was quantified by means of weighing, and then evaluated via calorimetry and thermogravimetric analysis as well as proximal and elemental analysis. The results showed that these materials met the criteria for direct combustion, exhibiting both a low nitrogen content of 0.30 ± 0.12% and ash values of 6.20 ± 1.20%. Among the analyzed varieties, CB 40-69 stood out as the most suitable for power generation within the cogeneration system; this was attributed to its superior dry calorific value of 17.37 ± 1.45 MJ kg−1, greater presence of volatile materials, and negligible ash content. Variety CB 40-69 (157.91 t ha−1) reported the highest biomass and bagasse production (56.32 t ha−1). Analysis of the SCB structure concluded that the three varieties did not differ significantly in their contents of lignin, hemicellulose, and cellulose, which is essential to implementing an industrial process for bioethanol production.

A comparative cradle-to-gate life cycle assessment of three cotton stalk waste sustainable applications

This paper presents a novel approach to utilizing agricultural waste. It compares three different applications for cotton stalks: fabrication of wood composites, bioethanol production, and biogas cradle-to-gate Life cycle assessment production processes. Cotton cultivation generates a lot of debris, mostly cotton stalks, which are incinerated or landfilled, Sustainable resource management is critical for maintaining the ecosystem, and economic stability, and promoting social fairness since it ensures the long-term availability of resources while minimizing environmental damage. The investigation uses the Ecological Footprint, Impact 2002 +, Global Warming Damage Potential, Greenhouse Gas Protocol, Recipe Midpoint, Ecosystem Damage Potential, and CML IA Baseline—open LCA-enabled environmental sustainability assessments. The analysis showed that bioethanol has a lower carbon footprint and climate change impact than both wood composite and biogas production processes, as a result, this could cause a preference for bioethanol production as an environmentally friendly strategy for cotton stalks utilization. While human toxicity was higher in the biogas production process, it emits less fossil CO2 than biogenic CO2. The total climate change of wood composite, bioethanol, and biogas production processes was 0.01761, 0.011300, and 0.01083 points, respectively. This research helps accomplish wider ecological and economic aims by giving insights into sustainable waste management practices.

Real-Time Optimization with Modifier Adaptation Based on Dynamic Gradient Estimation

In this paper, an optimization strategy with modifier adaptation based on a mechanistic model and the estimation of the input-output map gradient is presented to solve optimization problems in real-time. The strategy consists of defining an optimization problem based on the process model with first-order modifiers in the objective function that include the information of the input-output map gradient to correct the uncertainties of the process model. The gradient of the input-output map is estimated by means of a differentiator based on a multivariable Super-Twisting algorithm. The proposed real-time optimization with modifier adaptation strategy is implemented in a bioethanol production process and validated through closed-loop simulations.

Microbial bioethanol production from locally sourced corncobs through saccharification and fermentation using Aspergillus niger and Saccharomyces cerevisiae


 The utilization of agricultural residues, specifically corncobs, as a renewable feedstock for bioethanol production holds promise in sustainable energy generation. This study investigates the feasibility of microbial bioethanol production from locally sourced corncobs through co-digestion involving Aspergillus niger and Saccharomyces cerevisiae. The process involved washing the corncobs, grinding them, and then hydrolyzing the corncob flour with cultured Aspergillus niger. The resulting sugar syrup was then fermented with Saccharomyces cerevisiae to produce ethanol. The process was optimized to obtain the highest ethanol yield. The results indicated that the process developed achieved a maximum ethanol yield of 33.2, 36.7, and 45.5% from the triplicate digesters used with a percentage purity in the range of 62.06% to 87.69% and a mean volume of ethanol recovery of 145 mL per 400 mL of the fermented product. This yield was obtained when the temperature of the hydrolysis using inoculum and saccharification were maintained at 27 °C. Additionally, the optimal substrate concentration for maximum ethanol yield was found to be 50 % (w/v). The study demonstrates the potential of corncobs obtained from local mashing as a source of fermentable sugars for the microbial production of bioethanol. Additionally, the results provide a basis for the development of an efficient and economically feasible process for production of bioethanol from corncobs obtained from local mashing.

From Saccharomyces cerevisiae to Ethanol: Unlocking the Power of Evolutionary Engineering in Metabolic Engineering Applications.

Increased human population and the rapid decline of fossil fuels resulted in a global tendency to look for alternative fuel sources. Environmental concerns about fossil fuel combustion led to a sharp move towards renewable and environmentally friendly biofuels. Ethanol has been the primary fossil fuel alternative due to its low carbon emission rates, high octane content and comparatively facile microbial production processes. In parallel to the increased use of bioethanol in various fields such as transportation, heating and power generation, improvements in ethanol production processes turned out to be a global hot topic. Ethanol is by far the leading yeast output amongst a broad spectrum of bio-based industries. Thus, as a well-known platform microorganism and native ethanol producer, baker's yeast Saccharomyces cerevisiae has been the primary subject of interest for both academic and industrial perspectives in terms of enhanced ethanol production processes. Metabolic engineering strategies have been primarily adopted for direct manipulation of genes of interest responsible in mainstreams of ethanol metabolism. To overcome limitations of rational metabolic engineering, an alternative bottom-up strategy called inverse metabolic engineering has been widely used. In this context, evolutionary engineering, also known as adaptive laboratory evolution (ALE), which is based on random mutagenesis and systematic selection, is a powerful strategy to improve bioethanol production of S. cerevisiae. In this review, we focus on key examples of metabolic and evolutionary engineering for improved first- and second-generation S. cerevisiae bioethanol production processes. We delve into the current state of the field and show that metabolic and evolutionary engineering strategies are intertwined and many metabolically engineered strains for bioethanol production can be further improved by powerful evolutionary engineering strategies. We also discuss potential future directions that involve recent advancements in directed genome evolution, including CRISPR-Cas9 technology.