Biomass For Ethanol Production Research Articles

Exploring the Utilization Potential of Spirogyra sp. Biomass for Ethanol Production: A Study on Saccharification Optimization and High-Temperature Ethanol Fermentation

Spirogyra sp. is one of the potential feedstocks for bioethanol production, owing to its high carbohydrate and low lignin contents. However, to date, its use has scarcely been reported, particularly in high-temperature ethanol fermentation. The present study investigated the use of Spirogyra biomass as a bioethanol feedstock by optimizing the conditions for biomass saccharification, followed by ethanol fermentation via thermotolerant yeasts, i.e., Saccahromyces cerevisiae DBKKU Y-53, Kluyveromyces marxianus DBKKU Y-102, and Pichia kudriazevii RZ8-1. The optimization of the algal biomass hydrolysis using response surface methodology (RSM) showed that a maximum total sugar production of 14.75 ± 0.13 g/L was attained using 2.67% (v/v) sulfuric acid, 7.97% (w/v) of biomass loading, and 20 min of hydrolysis time. The fermentation of Spirogyra sp. hydrolysate containing 20 g/L of total sugar at 37 °C showed that S. cerevisiae DBKKU Y-53, K. marxianus DBKKU Y-102, and P. kudriazevii RZ8-1 produced 4.05 ± 0.35 g/L, 4.48 ± 0.13 g/L, and 4.47 ± 0.19 g/L of ethanol, respectively. At 40 °C, lower ethanol production of 1.07 ± 0.47 g/L, 3.93 ± 0.24 g/L, and 3.97 ± 0.19 g/L, respectively, were observed. Nevertheless, P. kudriazevii RZ8-1 exhibited a promising potential for the further development of a high-temperature ethanol fermentation process.

Numerical research on biomass wastewater treatment using double-partition vessel with off-centered impellers

Limited by single function, it is difficult for the traditional stirred vessels to meet the requirements of mixing system in biomass wastewater treatment processes. The estimation of biomass wastewater stirring reactor performance by computational fluid dynamics (CFD) during multiphase reactions is important, due to the uncertainty in the numerical results. In this study, a novel double-partition stirred vessel with eccentrically located impellers was developed for the special subject. In addition, many simulations were carried out with the wastewater from biomass ethanol production as the medium to ensure the high reactor performance. The fluid flow was simulated and analyzed using the turbulent RNG k-ε model and multi reference frames. A good agreement is found between the simulation results and the confirmatory experiment. Moreover, the weir crest and interconnected pore were specially designed for the establishment of the circulation of fluid to maintain different technological conditions in the two regions. The distributions of radial velocities and tangential velocities were concentrated near the stirring blade. From the velocity profile, it is deduced that the flow pattern in the stirred vessel is insensitive to Reynolds number. Finally, this simulation study could contribute to the improvement and optimization of the structure, as well as the operation of the novel stirred vessel. Keywords: biomass, wastewater treatment, double-partition vessel, computational fluid dynamics DOI: 10.25165/j.ijabe.20231602.7285 Citation: Zhang W, Yang Y J, Qian W M, Ma L L, Chen L G, Liu N, et al. Numerical research on biomass wastewater treatment using double-partition vessel with off-centered impellers. Int J Agric & Biol Eng, 2023; 16(2): 232-240.

Techno-economic evaluation of second-generation ethanol from sugarcane bagasse: Commercial versus on-site produced enzymes and use of the xylose liquor

Biomass ethanol production presents shortcomings related to enzymes cost and efficiency of xylose fermentation. Commercial enzymes used in second-generation ethanol (2GE) plants are produced off-site/offshore, with the additional formulation, transportation and storage costs. Alternatively, lower cost cellulases can be produced on-site. This study focused on the techno-economic evaluation of enzymes produced on-site versus commercial. Another limiting feature of the 2GE technology is the use of the hemicellulose sugars for ethanol fermentation. Thus, this work addressed its use for biogas production. Process systems engineering tools were used to evaluate four different configurations of a 2GE plant annexed to an already existent autonomous distillery. The application of the methodology allowed useful perceptions of the ethanol and biogas production, water and electricity consumption, and economic profitability. The need of a second fungus strain for the on-site enzyme production was identified as the main bottleneck of this cellulase production process, which is an important insight that could guide the future research efforts.

Simulation and economic evaluation of different process alternatives for the fermentation and distillation steps of ethanol production

The intensification of climate change and other phenomena associated with the growing pollution of the planet have increasingly highlighted the need for energy sources that are less harmful to the environment. There is currently a strong trend towards the substitution of non-renewable and highly polluting energy sources, such as petroleum derivatives, by renewable sources, from the use of biomass, for example. Sugarcane is a widely used biomass for ethanol production in Brazil, which is the second largest ethanol producer in the world. Although well established in the country, ethanol production is very complex and process alternatives are continually being developed to make it more efficient. This work aims to simulate the fermentation and distillation stages of the ethanol production process from sugarcane juice, considering both the conventional route and alternative technologies, and compare them through an integrated economic analysis. In the simulations, the yeast growth rate in the fermenter was considered through the creation of a solid pseudocomponent, which is a differential of this work. For fermentation, the conventional route was compared with Low Temperature Fermentation and Vacuum Extractive Fermentation. For distillation, besides the conventional process, Double Effect Distillation was also analyzed. It was concluded that the process designs of Low Temperature Fermentation + Conventional Distillation and Vacuum Extractive Fermentation + Double Effect Distillation are economically advantageous when compared to the conventional one, with annual net profits up to 31.6% higher, showing the possibility of obtaining a more efficient and profitable process, or a reduction of up to 5% in the ethanol price through the implementation of these alternative technologies.

EFFECT OF ULTRASOUND PRE-TREATMENT ON DRYING KINETICS AND QUALITY PROPERTIES OF JERUSALEM ARTICHOKE

-- Jerusalem artichoke (Helianthus tuberosus L.) is primarily used as a biomass for ethanol production. It is also utilized for human consumption as a healthy snack by having good nutritional value and inulin content. In this study, ultrasound pre-treatment (USPT) was selected to minimize drying defects and 5, 10 and 15 min. treatments were applied before hot air drying at 60 °C and 80 °C. The effect of pre-treatment on drying performances and properties as color, total phenolic content and total antioxidant were investigated. Effective diffusion coefficient values ​​ranged from 1.72 × 10-8 m2/min to 2.94 × 10-8 to m2/min, and it was observed that the effective moisture diffusion coefficient was higher in the samples where ultrasound was applied compared to the control sample. L * value 72.72 ± 2.71 was found highest at samples that were 5 minutes ultrasound treated and dried at 60 ° C for 60 minutes. The highest antioxidant and phenolic content in the drying process at 60 °C was determined in the samples where ultrasound was applied for 15 minutes. Consequently, more conserved quality in shorter drying time with desired end product moisture content can be achieved by the application of USPT.

Effect of Choline Acetate on the Yeast Cells During Fermentation: Kinetics Approach

Background: Ionic liquids (ILs) are claimed as green solvents and have demonstrated ability in the dissolution of several biomaterials and polymers, thus promoting their applications in wide scope. The aim of this study was to evaluate the yeast cells in the ionic liquid (IL), choline acetate [Cho]OAc as an eco-friendlier IL for their growth and ability of fermentation of the empty fruit bunch (EFB) biomass for ethanol production via monitoring the cell growth curve and kinetics. Methods: The Saccharomyces cerevisiae was cultured for five days on yeast extract-peptone-dextrose (YPD) agar and the sub-culturing was carried out every two weeks to evaluate the growth of yeast in [Cho]OAc at different concentrations; 5%, 10%, and 20%, where it was pre-cultivated for 24 h at 30 °C and 150 rpm in a shaking incubator as a control culture. Yeast cell number was determined by counting using a hemocytometer. Also, the kinetic growth of yeast during the fermentation of EFB was evaluated. Result: Cell concentration increased, ethanol production increased along with the optical density with the peak reached at 72 h, then declined. Enzymatic hydrolysis process followed by fermentation of EFB using [Cho][OAc] improved the yield of sugar, saccharification and ethanol around 1.938, 2.879, and 2.165 times in comparison with untreated EFB with IL. Furthermore, values of specific growth rates obtained in IL-medium and non-IL-medium are applicable for ethanol production to take place. The results showed the ability of yeast cells for fermentation even in the presence of IL. Conclusion: The results showed that the presence of the IL did not suppress the growth of the yeast cells and did not impair the fermentation productivity.

Techno-economic analysis of bioethanol production from microwave pretreated kitchen waste

Cost-effective production of bioethanol from waste material is becoming the need of the hour to combat the exhaustive nature of fossil fuel. In this study, bioethanol was produced from microwave-pretreated kitchen waste at high dry material consistency. Pretreatment was performed for 30 min at a constant power of 90 W. Liquefaction/saccharification was done with in-house produced amylase from Bacillus licheniformis MTCC 1483. The liquefaction step was optimized using response surface modeling. Three factors, viz. pH, concentration of dry substrate and amylase, were optimized by using reducing sugar and ethanol yield as response. The optimum conditions of input parameters obtained were pH 7.5, dry material 40% (w/v) and amylase 15 IU g−1. The process developed in the present study leads to 0.129 g ml−1, i.e., 0.32 g per g biomass ethanol production. The novelty of the manuscript lies in the fact that no acid/alkali hydrolysis was carried out for the release of reducing sugar. Instead, microwave treatment was carried out at low power for longer time so as to release maximum sugar. The cost incurred in bioethanol production was also estimated by taking cost of chemicals, instruments and operating cost in account. The total cost of bioethanol produced in the present study was calculated as 0.143 $/l of ethanol. A 8.32-fold decrease in price of ethanol produced in the present study was observed when compared to the market selling price of ethanol. This makes the developed process economically and industrially feasible.

The social, economic, and environmental implications of biomass ethanol production in China: A multi-regional input-output-based hybrid LCA model

As an alternative to conventional liquid fuels, bioethanol holds the promise of transitioning to a clean and low-carbon energy future. China’s bioethanol industry is at its nascent stage. In this study, we developed a hybrid life cycle assessment model that integrates the multi-regional input-output (MRIO) approach and specific production data to evaluate the social, economic, and environmental (i.e. the triple-bottom-line, TBL) impacts of the bioethanol sector in China’s economic systems. The MRIO model was constructed using the 2012 MRIO table, and the data for the typical technologies of bioethanol production were leveraged. To be specific, we evaluated employment creation, economic stimulus, and energy use of bioethanol production in 28 scenarios in Henan province. The results show that compared to petroleum refining, bioethanol production is more effective for economic stimulus and energy saving, but less effective at job creation. The impact of bioethanol production varies by technologies. For every 1 million yuan of bioethanol production in China’ economic system, first-generation technology offers a projected 1.92 million yuan in economic growth and job creation of 2.06 full-time equivalent, while the second-generation technology offers a lower energy consumption (1.19 TJ). In most scenarios, the upstream sectors account for more than half of the TBL impacts of biofuel production. This study helps to quantify the TBL impacts associated with the gasoline-to-bioethanol transition in China, envisions the green opportunities for impact mitigation, and sheds light on the potential direction for robust planning and policy making to advance the bioethanol industry’s development.

Optimization of hyper-thermal acid hydrolysis and enzymatic saccharification of Ascophyllum nodosum for ethanol production with mannitol-adapted yeasts.

In this study, Ascophyllum nodosum was studied as a biomass for ethanol production. A. nodosum was degraded to monosaccharide by hyper-thermal (HT) acid hydrolysis and enzymatic saccharification and analyzed using response surface methodology (RSM) and the Michaelis-Menten equation. Maximum monosaccharide concentrations of 20.3g/L glucose and 7.0g/L mannitol were obtained from HT acid hydrolysis and enzymatic saccharification from 8%(w/v) of A. nodosum. Fermentation was conducted using Pichia stipitis and P. angophorae adapted to high mannitol concentrations. Neither non-adapted P. stipitis and P. angophorae nor adapted P. stipitis could ferment all mannitol in the A. nodosum hydrolysate. Adapted P. angophorae produced the highest ethanol concentration among various yeasts, with ethanol production reaching 13.6g/L with an ethanol yield (YEtOH) of 0.50. Optimization of HT acid hydrolysis and enzymatic saccharification, in combination with the use of adapted yeast, could enhance overall A. nodosum ethanol fermentation yields.

Enhancement of Ethanol Production via Hyper Thermal Acid Hydrolysis and Co-Fermentation Using Waste Seaweed from Gwangalli Beach, Busan, Korea.

The waste seaweed from Gwangalli beach, Busan, Korea was utilized as biomass for ethanol production. Sagassum fulvellum (brown seaweed, Mojaban in Korean name) comprised 72% of the biomass. The optimal hyper thermal acid hydrolysis conditions were obtained as 8% slurry contents, 138 mM sulfuric acid, and 160°C of treatment temperature for 10 min with a low content of inhibitory compounds. To obtain more monosaccharides, enzymatic saccharification was carried out with Viscozyme L for 48 h. After pretreatment, 34 g/l of monosaccharides were obtained. Pichia stipitis and Pichia angophorae were selected as optimal co-fermentation yeasts to convert all of the monosaccharides in the hydrolysate to ethanol. Co-fermentation was carried out with various inoculum ratios of P. stipitis and P. angophorae. The maximum ethanol concentration of 16.0 g/l was produced using P. stipitis and P. angophorae in a 3:1 inoculum ratio, with an ethanol yield of 0.47 in 72 h. Ethanol fermentation using yeast co-culture may offer an efficient disposal method for waste seaweed while enhancing the utilization of monosaccharides and production of ethanol.

Assessment of Sugarcane Billet Harvester on Recovery of Sweet Sorghum Biomass for Ethanol Production

Sweet sorghum (Sorghum bicolor L. Moench) is a promising bioenergy crop for the production of ethanol and bio-based products. Sugarcane billet harvesters can be used to harvest sweet sorghum. Multiple extractor fan speed settings of these harvesters allow for separating the extraneous matter in the feedstock, which has been associated with increased milling throughput and better juice quality at the processing facility. This removal is not completely selective, and some stalk material is also lost. These losses can be higher for sweet sorghum than sugarcane due its lower weight. This paper presents an assessment of how the speed of the primary extractor fan of a sugarcane billet combine used for harvesting sweet sorghum affects the biomass yield, biomass losses, and quality at delivery for the production of ethanol from extracted juice and fiber. Three primary extractor fan speeds (0, 800, and 1100 rpm) were evaluated. Higher fan speeds decreased fresh biomass yields by up to 28.3 Mg ha−1. Juice quality was not significantly different among treatments. Ethanol yield calculated from sweet sorghum harvested at 0 rpm was 6075 L ha−1. This value decreased by about half for material harvested at 1100 rpm due to the differences in biomass yield.

Phytoremediation of metal-contaminated soils by the hyperaccumulator canola (Brassica napus L.) and the use of its biomass for ethanol production

This study evaluates the phytoremediation potential of canola biomass, which was grown on soils contaminated by several metals. The increase in metal concentration was measured in different parts of the growing biomass. Nearly 95mg zinc/kg soil of the zinc supplied to the soil accumulated within the roots of canola. To test the suitability of the canola biomass for bioethanol production, a saccharification was performed after phytoextraction of metals. Armillaria gemina and Pholiota adiposa were co-cultured to obtain a highly active lignocellulase cocktail. Saccharification yields (SY) of 71.8% and 74.4% were obtained with biomass contaminated with nickel and copper, respectively. Under similar conditions, Celluclast® 1.5L in combination with commercial β-glucosidase resulted in a SY of 73.4%. Fermentation using the hydrolysate of canola biomass used in the phytoremediation yielded 68.9% of bioethanol. To our knowledge, this is the first study where canola biomass used for phytoremediation was tested for bioethanol production through saccharification.

Effects of enzyme loading, densification, and storage on AFEX-pretreated biomass for ethanol production.

Corn stover, switchgrass, and prairie cordgrass were treated with an ammonia fiber expansion (AFEX) process and a novel densification method (ComPAKco). Separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) were used to evaluate impacts of densification. ComPAKco densification is characterized by low-temperature and low-energy requirements, resulting in compacted biomass briquettes (CBB) 1-2cm square, with a bulk density of 380-460kg/m(3). Feedstocks were evaluated before and following AFEX pretreatment, after densification, and after storage. Two enzyme doses were tested. The low rate used 5 filter paper units (FPU) of Spezyme CP (cellulase) and 21.3 cellobiase units (CBU) of Novozyme 188 (aka NS50010 [β-glucosidase]) per gram of glucan. The high dosage rate was three times higher and resulted in 40-56% and 33-82% higher ethanol yields with SHF and SSF, respectively. Trials revealed no adverse effect on ethanol yield following densification or 6-month storage of densified, AFEX-pretreated feedstocks.

Integrated strategic and tactical biomass–biofuel supply chain optimization

To ensure effective biomass feedstock provision for large-scale biofuel production, an integrated biomass supply chain optimization model was developed to minimize annual biomass-ethanol production costs by optimizing both strategic and tactical planning decisions simultaneously. The mixed integer linear programming model optimizes the activities range from biomass harvesting, packing, in-field transportation, stacking, transportation, preprocessing, and storage, to ethanol production and distribution. The numbers, locations, and capacities of facilities as well as biomass and ethanol distribution patterns are key strategic decisions; while biomass production, delivery, and operating schedules and inventory monitoring are key tactical decisions. The model was implemented to study Miscanthus-ethanol supply chain in Illinois. The base case results showed unit Miscanthus-ethanol production costs were $0.72L(-1) of ethanol. Biorefinery related costs accounts for 62% of the total costs, followed by biomass procurement costs. Sensitivity analysis showed that a 50% reduction in biomass yield would increase unit production costs by 11%.

A Canadian Ethanol Feedstock Study to Benchmark the Relative Performance of Triticale: II. Grain Quality and Ethanol Production

Cereal grain ethanol production may need to supplement biomass ethanol production to meet the increasing long‐term demand for ethanol. A study was initiated to benchmark the relative performance of triticale (×Triticosecale ssp.) to wheat (Triticum aestivum L.) classes utilized for ethanol production. Ten cultivars: three triticale, two Canada prairie spring (CPS) wheat, three Canada western soft white spring (CWSWS) wheat, one Canada western red spring (CWRS) wheat, and one Canada western general purpose (CWGP) wheat cultivars were grown at 45 locations across Canada from 2006 to 2009. The locations were subgrouped by agroecological zone for western Canada, by province for Ontario and Quebec, and Charlottetown, PEI, for the Maritimes. The greatest grain yield was usually observed for Hoffman (red spring wheat) followed by triticale cultivars and CWSWS cultivars. Ethanol yield varied by region as a reflection of grain yield, and differences among cultivars generally were: triticale (excluding Tyndal) = Hoffman = CWSWS > CPS > CWRS. Ethanol concentration was least for Tyndal triticale and AC Superb CWRS. Stability assessments indicated that Pronghorn and AC Ultima triticales and Bhishaj CWSWS wheat provide consistent and high ethanol yields. The other CWSWS cultivars, AC Sadash and AC Andrew, had similarly high ethanol yields but were variable, indicating that utilization outside the Parkland and Western Prairies agroecological zones could pose greater risk for ethanol plants over Pronghorn and AC Ultima. Ethanol fermentation plants could therefore increase efficiency by replacing CPS wheat feedstocks with select triticales and potentially improve the consistency of production by using select triticales in regions where CWSWS wheats are less stable.

Bioprospecting thermophiles for cellulase production: a review

Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

Study on fuel biomass ethanol production in a double cropping system - analysis using regional condition in Tochigi prefecture.

Study on fuel biomass ethanol production in a double cropping system - analysis using regional condition in Tochigi prefecture.

Response of Cellulase Activity in pH-Controlled Cultures of the Filamentous Fungus Acremonium cellulolyticus

Cellulase production was investigated in pH-controlled cultures of Acremonium cellulolyticus. The response to culture pH was investigated for three cellulolytic enzymes, carbomethyl cellulase (CMCase), avicelase, and β-glucosidase. Avicelase and β-glucosidase showed similar profiles, with maximum activity in cultures at pH 5.5–6. The CMCase activity was highest in a pH 4 culture. At an acidic pH, the ratios of CMCase and avicelase activity to cellulase activity defined by filter paper unit were high, but at a neutral pH, the β-glucosidase ratio was high. The pH 6.0 culture showed the highest cellulase activity within the range of pH 3.5–6.5 cultures. The saccharification activity from A. cellulolyticus was compared to those of the cellulolytic enzymes from other species. The A. cellulolyticus culture broth had a saccharification yield comparable to those of the Trichoderma enzymes GC220 and Cellulosin T2, under conditions with the same cellulase activity. The saccharification yields from Solka floc, Avicel, and waste paper, measured as the percent of released reducing sugar to dried substrate, were greater than 80% after 96 h of reaction. The yields were 16% from carboxymethylcellulose and 26% from wood chip refiner. Thus, the A. cellulolyticus enzymes were suitable for converting cellulolytic biomass to reducing sugars for biomass ethanol production. This study is a step toward the establishment of an efficient system to reutilize cellulolytic biomass.

G0801-2-2 未利用木材を用いたバイオエタノール生産にかかる基礎研究(動力エネルギー部門一般(2))

Recently, the biomass ethanol production using grain is done. On the other hand, the sudden rise of fodder and the fertilizer happens because grain was used for the bio-ethanol production, and the review of the raw material is being requested by the society. Then, it aimed at the bio-ethanol production that used unused woods such as the abolition woods and thinned woods in this study. We experimented on the method of the decomposition of wood that used solar energy and the photocatalyst without using a chemical oxidative decomposition of a past sulphuric acid method etc. As a result, the wood flour was decomposed to lignin and the holocellulose by the reaction of ultraviolet rays and the photocatalyst. In addition, sugar was obtained by the cellulose's that had been obtained here being similarly decomposed. However, the improvement of the treatment efficiency is future tasks in this method.

BIOMASS FOR ELECTRICITY AND PROCESS HEAT AT ETHANOL PLANTS

Biomass can provide electricity and process heat at dry-grind ethanol plants to both reduce costs and improvethe net energy value of ethanol production. Distillers dried grains with solubles (DDGS), which are coproducts of ethanolproduction, can potentially be used for energy. Corn stover is another potential biomass energy source for ethanol plants.Biomass (DDGS and corn stover) alternatives to provide process heat and electricity at corn dry mill ethanol plants areevaluated. Corn dry grind ethanol production using biomass (DDGS or corn stover) to meet process energy needs andgenerate electricity achieves net energy values in the range of 20 to 30 MJ/L (72,000 to 108,000 Btu/gal) of ethanol, whichequals or exceeds previous estimates for biomass ethanol production. There are significant annual energy cost savings/returnsfor a 150 million L (40 million gal) per year plant capacity over a range of natural gas and biomass prices to apply toadditional capital and operating costs required for a biomass energy system. Electricity generation is potentially an importantcontributor to the annual energy cost savings/returns because of the ability to effectively use waste heat from electricitygeneration to meet process energy needs. Important next steps are to evaluate capital and operating costs of biomasscombustion/gasification, emission control, biomass fuel handling, and electricity generation technologies to determineoverall economic feasibility.