Feedstock For Bioethanol Production Research Articles

The Effect of Ultrasonication and Delignification Treatment on the Sugar Released Value of Wood

The objective of these research was to study the impact of ultrasonication and delignification pretreatments in several wood species on their easiness for enzymatic hydrolysis, having the potential to be developed as the feedstocks for bioethanol production. Four different wood species from three botanical gardens in Indonesia have been selected, i.e., Gymnostoma sumatranum, Firmiana malayana, Pterocarpus indicus, and Alstonia scholaris, due to their higher sugar released values than a fast-grown tree, Sengon (Paraserianthes falcataria), when all were directly enzymatically hydrolyzed without pretreatment. The sugar released values after ultrasonication and enzymatic hydrolysis were between 3 – 5.5 mg/100 mg wood meal. When delignification pretreatment was performed, the sugar released values were higher than those with ultrasonication, ranging between 4 – 10.2 mg/100 mg wood meal. All the sugar released values after pretreatment were higher than those without pretreatment. Gymnostoma sumatranum was selected as the most potential wood species in this study due to its consistency among the species producing highest sugar released across different treatments. The SEM results showed that there was no significant changes in the morphological structure of the untreated fiber before and after enzymatic saccharification since it still had a complex structure due to the high lignin content. However, after the delignification treatment, the surface morphology of the fiber showed a decrease in the number of pits of the fiber, the surface residual of pits were reduced, parallel lines were more clearly visible, and the fiber structure was damaged with more small holes presented. The surface morphology of the fiber from the wood powder having delignification pretreatment supports the sugar released values which shows that the these values were higher than other treatments due to more recalcitrant substances were degraded, making it was easier for enzymes to break down cellulose. After ultrasonication, the SEM result showed less disrupted cell wall compared to after delignification which confirmed the higher sugar released data with delignification.

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.

Exploring the Prospects of Fermenting/Co-Fermenting Marine Biomass for Enhanced Bioethanol Production

With the rising demands for renewable fuels, there is growing interest in utilizing abundant and sustainable non-edible biomass as a feedstock for bioethanol production. Macroalgal biomass contains a high content of carbohydrates in the form of special polysaccharides like alginate, agar, and carrageenan that can be converted to fermentable sugars. In addition, using seagrass as a feedstock for bioethanol production can provide a sustainable and renewable energy source while addressing environmental concerns. It is a resource-rich plant that offers several advantages for bioethanol production, including its high cellulose content, rapid growth rates, and abundance in coastal regions. To reduce sugar content and support efficient microbial fermentation, co-fermentation of macroalgae with seagrass (marine biomass) can provide complementary sugars and nutrients to improve process yields and economics. This review comprehensively covers the current status and future potential of fermenting macroalgal biomass and seagrass, as well as possible combinations for maximizing bioethanol production from non-edible energy crops. An overview is provided on the biochemical composition of macroalgae and seagrass, pretreatment methods, hydrolysis, and fermentation processes. Key technical challenges and strategies to achieve balanced co-substrate fermentation are discussed. The feasibility of consolidated bioprocessing to directly convert mixed feedstocks to ethanol is also evaluated. Based on current research, macroalgae-seagrass co-fermentation shows good potential to improve the bioethanol yields, lower the cost, and enable more optimal utilization of diverse marine biomass resources compared to individual substrates.

Technoeconomic analysis of a fungal pretreatment-based cellulosic ethanol production

Cellulosic biomass shows great potential as feedstock for bioethanol production. Despite clear benefits in terms of greenhouse gas mitigation and bioproduct potential, the commercial production of cellulosic ethanol remains economically challenging at the current state of technology. This paper presents a technoeconomic analysis of a fungal pretreatment-based cellulosic ethanol plant with a processing capacity of 2000 tonnes of switchgrass per day. The production process model was designed and simulated using SuperPro Designer. The plant's ethanol yield, capital investment per unit capacity, and unit ethanol production cost were estimated to be 211.90 L/t of switchgrass, $ 3.60/L, and $ 1.44/L of ethanol, respectively. Fungal pretreatment was the major contributor (72%) to the total capital investment, mainly due to the large quantity of equipment required in the process. A positive net present value (NPV) was generated for the baseline model at ethanol selling price of $ 1.50/L, which increased by 5-fold for 80% glucose yield. Glucose yield was the most sensitive to NPV for all the process parameters evaluated.

Triticale and sorghum as feedstock for bioethanol production via consolidated bioprocessing

Corn starch is currently the primary feedstock for bioethanol production, but concerns about food security have prompted the evaluation of alternative cereals as feedstock. Two potential candidates, triticale and sorghum, can be grown on marginal farming land and mainly serve as animal feed. This study assessed flour and bran-like fractions of triticale and sorghum grains as feedstocks for bioethanol production using a consolidated bioprocessing approach. A Saccharomyces cerevisiae Ethanol Red™-derived amylolytic strain (ERT12) achieved ethanol conversion efficiencies of 100 and 96% from sorghum (after 96 h) and triticale flour (after 168 h), respectively. Supplementation with 10% of the recommended STARGEN™ 002 enzyme loading halved the fermentation time for sorghum and triticale flour. The raw starch in sorghum flour was more digestible than in triticale flour under consolidated bioprocessing conditions, whereas simultaneous saccharification and fermentation proved more effective for triticale flour. The two substrates also showed different hydrolysis patterns, which may be linked to their amylopectin content. This study demonstrated that both substrates could be converted to ethanol using only an efficient amylolytic strain without nitrogen supplementation. However, process development for biofuel production may require different fermentation configurations to be optimised for each substrate.

Process simulation-based scenario analysis of scaled-up bioethanol production from water hyacinth.

The online version contains supplementary material available at 10.1007/s13399-023-03891-w.

Ryegrass as a feedstock for bioethanol production

Ryegrass as a feedstock for bioethanol production

Insight into the effective utilization of cotton spinning wastes from textile mills for the production of bioethanol

Sustainable feedstocks are one of the main issues with the manufacturing of bioethanol. The present work was focused to evaluate the potentials of 10 different cotton spinning wastes for bioethanol production using alkali pretreatment. The characterization results confirmed that the cotton spinning wastes are rich in cellulose (55–86 %w/w) content. Among the various alkali concentrations, temperatures, and times for pretreatment of cotton spinning wastes, 12 % NaOH, 5 °C, and 3 h resulted in optimum cellulose recovery and crystallinity reduction of 98 % and 88 %, respectively. The pretreatment rate of NaOH on cotton spinning wastes followed first-order reaction kinetics with an activation energy of 4.91 KJ/mol, t. Additionally, the optimal conditions for saccharification of the pretreated biomass (1 percent w/v of solid loading, 60 FPU/g of cellulose at 96 h) led to an approximately 82 % hydrolysis efficiency. The subsequent fermentation process by Saccharomyces cerevisiae resulted in the maximum of 65 % ethanol yield at 60 h. These results suggests that the cotton spinning wastes can potentially be exploited as feedstock for bioethanol production in order to meet the future energy demands.

Reducing heavy metals content in sugarcane molasses and its effect on ethanol fermentation efficiency

The world energy scene is undergoing a period of transition. As the inevitability of exhaustion of fossil fuels is becoming increasingly intensive, efforts are exerted to find and use substitutes for energy. Bioethanol is one of the most substitute renewable fuels, contributing to the reduction of the global warming effect and negative environmental impact. Bioethanol production generally utilizes derivatives from food crops such as corn grain and sugarcane. In Egypt, sugarcane molasses is mainly used as feedstock for bioethanol production. However, molasses contains a concentration of heavy metals. Heavy metals are presented in high concentrations in the fermentation medium, causing a critical problem during fermentation. This study focuses on reducing heavy metals content in molasses to improve bioethanol fermentation using heating, centrifugation, sulfuric acid, and phosphoric acid. Heating and centrifugation were sufficient to decrease Ca with less effect on other metals. Sulfuric acid reduced heavy metals content and the reduction addition of phosphoric acid had less effect on lowering the levels of heavy metals in molasses. Pretreatment of molasses with 0.3% H

An integrated biorefinery approach for bioethanol production from sugarcane tops

Bioethanol from lignocellulosic biomass is a promising alternative to petroleum-based fuels to alleviate greenhouse gas emissions and reduce the dependency on fossil fuels. The lignocellulosic biomass is exploited for ethanol production due to its sustainability and abundance. Sugarcane tops, an agricultural residue, was employed in the present investigation to assess its potential as a feedstock for bioethanol production by adopting different fermentation approaches, namely separate fermentation, simultaneous saccharification and fermentation (SSF) and partially consolidated bioprocessing (PCBP). The present study demonstrated the potential of mono and co-fermentation for ethanol production. Comparison between separate fermentation and SSF using S.cerevisiae showed the latter to be more efficient with ethanol production of 5.69% (v/v) in 30.67 h of fermentation time than separate fermentation with 3.76% (v/v) ethanol in 48 h. An integrated fermentation strategy stated as partially consolidated bioprocessing (PCBP) was investigated to improve fermentation efficiency. This process integrates simultaneous pretreatment and saccharification (SPS), conducted by enzyme blends of laccase and cellulase followed by co-fermentation using S. cerevisiae and xylose-fermenting yeast AKBR 212. This approach resulted in a 7.57% (v/v) maximum ethanol concentration in 24.30 h. The different fermentation strategies involved enzymes and yeasts only, thus offering a green biotechnology approach towards converting sugarcane tops into bioethanol.

Enzymatic digestibility of pretreated dewaxed bamboo residues as feedstock for bioethanol production

Due to abundant availability, biofuel production from bamboo residues is gaining popularity. Bamboo biomass and its residues are widely available in the north-eastern part of India, which can be sustainably exploited for green energy production. The aim of the present study was to evaluate the pretreatments of dewaxed bamboo residues with dilute alkali (NaOH), and dilute acid, and the effect of pretreatment on biomass hydrolysis was performed with a commercial enzyme (Zytex). Results showed that maximum fermentable sugars were 490 mg/g obtained from 10% biomass with 0.6% (w/v) of alkali, and acid pretreated biomass produced 320 mg/g of sugars from 2% (w/v) acid with 10% biomass. Changes in biomass structure during the pretreatment process are correlated with FTIR, SEM, and component analysis for lignin, cellulose, and hemicelluloses. Fermentation studies of the hydrolysate showed that the yield of ethanol was 77% of the theoretical maximum at 36 h. Results indicate the scope of utilization of bamboo residues as substrates for biofuels, and alkaline pretreatment is an effective pretreatment process for bioethanol production.

Energy-efficient glucose recovery from chestnut shell by optimization of NaOH pretreatment at room temperature and application to bioethanol production

Biofuel policies are currently being implemented globally to reduce greenhouse gas emissions. The recent European regulation, Renewable Energy Directive (RED) II, states that renewable resources should be used as raw materials. In this study, chestnut shell (CNS), a food processing residue, was utilized as a feedstock for bioethanol production. Statistical optimization was performed to improve biomass-to-glucose conversion (BtG) from the CNS. In order to design an energy-efficient process, the pretreatment was fixed at room temperature in the numerical optimization. The optimal conditions derived from the predicted model are as follows: temperature of 25 °C, reaction time of 2.8 h, and NaOH concentration of 1.9% (w/w). Under optimal conditions, both predicted and experimental BtG were 31.0%, while BtG was approximately 3.3-fold improved compared to the control group (without pretreatment). The recovered glucose was utilized for bioethanol fermentation by Saccharomyces cerevisiae K35 and the ethanol yield was achieved to be 98%. Finally, according to the mass balance based on 1000 g CNS, glucose of 310 g can be recovered by the pretreatment; the bioethanol production was approximately 155 g. This strategy suggests a direction to utilize CNS as a potential feedstock for biorefinery through the design of an economical and energy-efficient pretreatment process by lowering the reaction temperature to room temperature.

The Interplay of Autoclaving with Oxalate as Pretreatment Technique in the View of Bioethanol Production Based on Corn Stover.

Bio-based treatment technologies are gaining great interest worldwide, and significant efforts are being afforded to develop technology for the use of lignocellulosic biomass. The potential of corn stover (CS) as a feedstock for bioethanol production was investigated by creating an optimal pretreatment condition to maximize glucose production. The current study undertook the impact of novel physico-chemical pretreatment methods of CS, i.e., autoclave-assisted oxalate (CSOA) and ultrasound-assisted oxalate (CSOU), on the chemical composition of CS and subsequent saccharification and fermentation for bioethanol production. The delignification was monitored by physicochemical characterizations such as SEM, XRD, FTIR, CHNs, and TGA. The results evidenced that delignification and enzymatic saccharification of the CS pretreated by CSOA was higher than CSOU. The optimum enzymatic saccharification operating conditions were 1:30 g solid substrate/mL sodium acetate buffer at 50 °C, shaking speed 100 rpm, and 0.4 g enzyme dosage. This condition was applied to produce glucose from CS, followed by bioethanol production by S. cerevisiae using an anaerobic fermentation process after 72 h. S. cerevisiae showed high conversion efficiency by producing a 360 mg/dL bioethanol yield, which is considered 94.11% of the theoretical ethanol yield. Furthermore, this research provides a potential path for waste material beneficiation, such as through utilizing CS.

Exploring the Bioethanol Production Potential of Miscanthus Cultivars

Miscanthus is a fast-growing perennial grass that attracts significant attention for its potential application as a feedstock for bioethanol production. This report explores the difference in the lignocellulosic composition of various Miscanthus cultivars, including Miscanthus × giganteus cultivated at the same location (mainly Lincoln, UK). It also assesses the sugar release profiles and mineral composition profiles of five Miscanthus cultivars harvested over a growing period from November 2018 to February 2019. The results showed that Miscanthus × giganteus contains approximately 45.5% cellulose, 29.2% hemicellulose and 23.8% lignin (dry weight, w/w). Other cultivars of Miscanthus also contain high quantities of carbohydrates (cellulose 41.1–46.0%, hemicellulose 24.3–32.6% and lignin 21.4–24.9%). Pre-treatment of Miscanthus using dilute acid followed by enzymatic hydrolysis released 63.7–80.2% of the theoretical glucose content. Fermentation of a hydrolysate of Miscanthus × giganteus using Saccharomyces cerevisiae NCYC2592 produced 13.58 ± 1.11 g/L of ethanol from 35.13 ± 0.46 g/L of glucose, corresponding to a yield of 0.148 g/g dry weight Miscanthus biomass. Scanning electron microscopy was used to study the morphology of raw and hydrolysed Miscanthus samples, which provided visual proof of Miscanthus lignocellulose degradation in these processes. The sugar release profile showed that a consequence of Miscanthus plant growth is an increase in difficulty in releasing monosaccharides from the biomass. The potassium, magnesium, sodium, sulphur and phosphorus contents in various Miscanthus cultivars were analysed. The results revealed that these elements were slowly lost from the plants during the latter part of the growing season, for a specific cultivar, until February 2019.

Optimizing bio-ethanol production from cabbage and onion peels waste using yeast (Saccharomyces cerevisiae) as fermenting agent

Production of bio-ethanol from lingocellulosic materials is providing a long-term sustainable for fuel supply. Cabbage and onion peels waste is one of cheap source of lignocellosic materials to serve as feedstock for bio-ethanol production. With the objective of evaluating its potential for bio-ethanol production, different concentrations (50g, and 100g) of Cabbage and onion peels waste treated with 1% diluted sulfuric acid and untreated were subjected to batch fermentation for 12 days with 0.5% and 1% yeast inoculums. Percent of bio-ethanol production, cell density and reducing sugars were measured at an interval of 4 days starting from the beginning. Results of these study showed that ethanol production was observed starting from the 4th day of fermentation, but its amount peaked 26.51 from 100g substrate with 1% inoculum on the 8th day of fermentation, and declined on 12th days (21.06%) from the same substrate concentration. Pretreated substrate showed significantly higher ethanol production than untreated. In agreement with ethanol production, cell density and reduction in reducing sugar were observed in the same pattern. Compared ethanol production between untreated substrates yield of 20.96%, and treated substrates yielded of 26.51%. Overall, this study showed that acid pre-treatment, inoculum concentration, fermentation period and substrate concentration affect the amount of bio-ethanol production. Finally, it can be concluded that the production of bioethanol from Cabbage and onion peels waste is economically and environmentally viable. Extensive use of these Wastes for bioethanol production may have twofold advantages, viz. reduction of its negative impact on environmental hygiene and generation of bio-ethanol.

Screening of microalgal isolates of the Persian Gulf and evaluation of their potential as the promising bioethanol feedstock

ABSTRACT The high levels of carbohydrates in some microalgae make them a promising feedstock for bioethanol production. The pretreatment of microalgal biomass is one of the most important stages to improve cell disruption for increasing the accessibility to the intracellular compounds. The isolation and identification of newly isolated microalgae that produce high biomass and carbohydrate production were done in this research. Among six isolates, Chlorella S-4 and Picochlorum D-8 showed the highest specific growth rates of 0.189 and 0.215 (µ day−1), respectively, from which the former showed a suitable self-precipitation property. A combination of cell disruption methods, including acid-thermal, acid-thermal/sonication bath, and acid-thermal/freeze & thaw pretreatment was applied to disrupt the cell wall of isolated microalgae on a laboratory scale. The effectiveness of cell disruption methods was evaluated based on total carbohydrate measurement. The maximum carbohydrate content of 22% and 27% of dry weight with the productivity of 7 and 6 mg/L/d was obtained from Chlorella S-4 and Picochlorum D-8, respectively, using acid-high thermal pretreatment (121°C for 20 min). This study is trying to demonstrate the Persian Gulf native microalgae potential for possible bioethanol production.

Evaluation of polyploid miscanthus lines usage efficiency as a feedstock for bioethanol production

Aim. Main aim of this research was the evaluation of theoretical bioethanol yield (per ha) from hexaploid giant miscanthus (Miscanthus х giganteus) and further comparison with conventional triploid form as well as with other bioethanol crops. Methods. Several mathematic functions were determined that describe yearly yield dynamics and equations, which were used in calculations of theoretical bioethanol yield. Results. The theoretical bioethanol yield was evaluated for different hexaploid miscanthus lines. The most productive in terms of ethanol yield were lines 108 and 202, from which potential bioethanol yield was found to be higher than in control line (6451 L/ha) by 10.7 % and 14.2% respectively and can reach 7144 L/ha and 7684 L/ha. Conclusions. It was determined that the most productive lines of polyploid miscanthus (lines 108 and 202) are able to compete with other plant cellulosic feedstocks for second-generation bioethanol production in Ukraine. However, these lines show bioethanol productivity than sweet sorghum, in the case when sweet sorghum is processed for obtainment of both first- and second-generation bioethanol.
 Keywords: bioenergy crops, biofuels, giant miscanthus, Miscanthus, polyploidy, second-generation bioethanol.

A Kinetic Study in Fermentation of Cocoa Pod Husk using Zymomonas Mobilis

In many years, bioethanol research has been an outstanding topic because of renewable energy issue. The aim of this research is focused on utilization of cocoa pod husk as a feedstock for bioethanol production through fermentation using Z. mobilis. Moreover, the kinetic model of cocoa pod husk fermentation using Z. mobilis as a microorganism was also preformed in this study. Fermentation of cocoa pod husk was carried out at room temperature for 0, 2, 4, 6, and 8 days of reaction. The bacteria were also varied with 8%, 10%, 12%, 14%, and 16% (v/v) of concentration towards the substrate mixture. The kinetic model was conducted by Michaelis – Menten equation followed by Eadie-Hofstee plot and batch kinetic data plot for its fitting parameter technique. The result of this study indicates that the slow reaction has occurred regarding the low value of conversion and small value of maximum reaction velocity. The highest conversion was achieved on the 8th day with 14% (v/v) of bacteria concentration that is 10.65%. The maximum velocity of reaction for 16% (v/v) of bacteria addition was obtained at approximately 0.0017 mol/L.hour.

Molecular mechanism underlying the effect of maleic hydrazide treatment on starch accumulation in S. polyrrhiza 7498 fronds

BackgroundDuckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. The starch content can be promoted by plant growth regulators after the vegetative reproduction being inhibited. Maleic hydrazide (MH) has been reported to inhibit plant growth, meantime to increase biomass and starch content in some plants. However, the molecular explanation on the mechanism of MH action is still unclear.ResultsTo know the effect and action mode of MH on the growth and starch accumulation in Spirodela polyrrhiza 7498, the plants were treated with different concentrations of MH. Our results showed a substantial inhibition of the growth in both fronds and roots, and increase in starch contents of plants after MH treatment. And with 75 µg/mL MH treatment and on the 8th day of the experiment, starch content was the highest, about 40 mg/g fresh weight, which is about 20-fold higher than the control. The I2-KI staining and TEM results confirmed that 75 µg/mL MH-treated fronds possessed more starch and big starch granules than that of the control. No significant difference for both in the photosynthetic pigment content and the chlorophyll fluorescence parameters of PII was found. Differentially expressed transcripts were analyzed in S. polyrrhiza 7498 after 75 µg/mL MH treatment. The results showed that the expression of some genes related to auxin response reaction was down-regulated; while, expression of some genes involved in carbon fixation, C4 pathway of photosynthesis, starch biosynthesis and ABA signal transduction pathway was up-regulated.ConclusionThe results provide novel insights into the underlying mechanisms of growth inhibition and starch accumulation by MH treatment, and provide a selective way for the improvement of starch production in duckweed.

Transformation of lignocellulose from corn stove for bioethanol production

The use of fossil fuels, as well as the environmental issues associated with their burning, has pushed for the development of clean, renewable energy sources. Biofuels made from lignocellulosic biomass are considered a carbon-neutral and sustainable method. As the demand for non-petroleum fuels grows, more attention will be placed on developing a cost-competitive liquid transportation biofuel like ethanol. This study was conducted to produce bioethanol utilizing the SHF (separate hydrolysis and fermentation) technique from corn stove lignocellulose. Pretreatment with sodium hydroxide at various concentrations was also studied. The influence of enzymatic saccharification, fermentation time, and substrate concentration on sugar yield and, eventually, ethanol production was investigated. Fermentation was carried out by using the enzymatically saccharified hydrolysate and monoculture of Saccharomyces cerevisiae. The results reveal that pretreatment with 2% NaOH followed by 48 hours of hydrolysis produced the maximum bioethanol production (30.21 ±0.13 g/L). This study findings indicated that alkali-pretreated corn stove might be used as a feedstock for bioethanol production, reducing reliance on fossil fuels.