Volume 2. Bioethanol Fuel Production Processes. II

Konur, O., Ed. 2023. Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2. Boca Raton, FL: CRC Press. DOI: https://doi.org/10.1201/9781003226499 eBook ISBN: 9781003226499. 466 pp.

This book provides an overview of the research on production processes for bioethanol fuels in general, hydrolysis of the pretreated biomass for bioethanol production, microbial fermentation of hydrolysates and substrates with yeasts for bioethanol production, and separation and distillation of bioethanol fuels from the fermentation broth, complementing the research on biomass pretreatments presented in the first volume.

It presents an overview of the research on biomass hydrolysis in general, wood hydrolysis, straw hydrolysis, and cellulose hydrolysis for bioethanol fuel production in the first section for biomass hydrolysis. It provides an overview of the research on microbial hydrolysate fermentation for bioethanol production in general, alternative fermentation processes for bioethanol fuel production such as simultaneous saccharification and fermentation (SSF) and consolidated biomass processing (CBP) compared with the separate hydrolysis and fermentation (SHF) process, metabolic engineering of microorganisms and substrates for bioethanol fuel production, and utilization of Saccharomyces cerevisiae for microbial fermentation of hydrolysates for bioethanol fuel production in the second section for hydrolysate fermentation.

It provides an overview of the research on the bioethanol fuel separation from the fermentation broth in the last section. This book is a valuable resource for the stakeholders primarily in the research fields of energy and fuels, chemical engineering, environmental science and engineering, biotechnology, microbiology, chemistry, physics, mechanical engineering, agricultural sciences, food science and engineering, materials science, biochemistry, genetics, molecular biology, plant sciences, water resources, economics, business, management, transportations science and technology, ecology, public, environmental and occupational health, social sciences, toxicology, multidisciplinary sciences, and humanities among others.

Part 3. Introduction to production processes for bioethanol fuels 48 pp.

1. Konur, O. 2023o. Production processes for bioethanol fuels: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 3-29. Boca Raton, FL: CRC Press. 27 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining the energy security in the supply shocks related to oil price shocks, COVID-19 pandemics, or wars in the aftermath of the Russian invasion of Ukraine. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. The research in the field of the production processes for bioethanol fuels has intensified in this context in the key research fronts of the pretreatment and hydrolysis of the feedstocks, fermentation of the hydrolysates, production of bioethanol fuels in general, and to a lesser extent evaluation, utilization, and distillation of bioethanol fuels. The research in this field has also intensified for the feedstocks of lignocellulosic biomass at large, cellulose, wood biomass, starch feedstock residues, and to a lesser extent lignin, grass biomass, industrial waste, sugar feedstocks, starch feedstocks, sugar feedstock residues, algal biomass, biosyngas, urban waste, food waste, and forestry waste. Thus, it complements the research on the feedstocks for the bioethanol fuels and evaluation and utilization of bioethanol fuels at large. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As there have been no published scientometric studies in this field, this book chapter presents a scientometric study of the research in the production processes for bioethanol fuels. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, Scopus keywords, and research fronts.

2. Konur, O. 2023p. Production processes for bioethanol fuels: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 30-48. Boca Raton, FL: CRC Press. 19 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol fuel production from the feedstocks through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. The influential research in the field of the production processes for bioethanol fuels has intensified in this context in the key research fronts of the pretreatment and hydrolysis of the feedstocks, and to a lesser extent fermentation of the hydrolysates and production of bioethanol fuels in general. The research in this field has also intensified for the feedstocks of wood biomass, cellulose, lignocellulosic biomass at large, and to a lesser extent starch feedstock residues, and grass. Thus, it complements the research on the feedstocks for the bioethanol fuels and evaluation and utilization of bioethanol fuels at large. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there has been a large number of review papers on the bioethanol fuels, there has been no review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of these most-cited 25 articles. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

Part 4. Biomass Hydrolysis for Bioethanol Production 165pp.

3. Konur, O. 2023q. Biomass hydrolysis: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 51-74. Boca Raton, FL: CRC Press. 24 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline and diesel fuels, in the fuel cells, and in the biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining the energy security in the supply shocks related to oil price shocks, COVID-19 pandemics, or wars in the aftermath of Russian invasion of Ukraine. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis and fermentation of the biomass. The research in the field of biomass hydrolysis has thus intensified in recent years as the hydrolysis of the agricultural residues, wood, biomass constituents, and grass have been widely researched to increase the sugar and bioethanol yield in this context. Further, on the individual terms, the most-prolific biomass have been cellulose, corn stover, lignin, wheat straw, lignocellulose, and to a lesser extent, rice straw, sugarcane bagasse, hemicellulose, grass, and food waste. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As there have been no scientometric studies on the biomass hydrolysis, this book chapter presents a scientometric study of the research in biomass hydrolysis. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of both these datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, keywords, and research fronts.

4. Konur, O. 2023r. Biomass hydrolysis: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 75-90. Boca Raton, FL: CRC Press. 16 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. In this context, the research in the field of biomass hydrolysis has thus been intensified in recent years as the hydrolysis of the agricultural residues, wood, biomass constituents, and to a lesser extent, hydrolysates and grass have been widely researched to increase the sugar and bioethanol yield. Further, on the individual terms, the most-prolific biomass have been cellulose, corn stover, lignin, hemicellulose, and to a lesser extent, lignocellulose, rice straw, and wheat straw. Although there have been a number of review papers on the biomass hydrolysis, there has been no updated review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of the most-cited 25 articles in the field of the biomass hydrolysis. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

5. Konur, O. 2023s. Wood hydrolysis: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 91-114. Boca Raton, FL: CRC Press. 24 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline and diesel fuels, in fuel cells, and in biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining energy security in supply shocks related to oil price shocks, COVID-19 pandemic, or wars in the aftermath of the Russian invasion of Ukraine and COVID-19 pandemic. However, it is necessary to pretreat the biomass to enhance the yield of bioethanol prior to bioethanol production through hydrolysis and fermentation of biomass and hydrolysates, respectively. Wood has been one of the most-studied biomasses for bioethanol production. In this context, research in the field of wood hydrolysis has thus intensified in recent years as enzymatic, chemical, and hydrothermal, and to a lesser extent, mechanical hydrolysis of wood has been widely researched to increase sugar and bioethanol yield. Further, on individual terms, the most prolific research fronts have been acid hydrolysis and steam explosion hydrolysis and to a lesser extent autohydrolysis, solvent hydrolysis, ionic liquid hydrolysis, liquid hot water hydrolysis, alkaline hydrolysis, and sulfite hydrolysis. On the other hand, the most prolific wood types have been hardwood, softwood, and wood in general and on individual terms, softwood in general, poplar, eucalyptus, pine, hardwood in general, bamboo, spruce, and to a lesser extent aspen, birch, and olive tree. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance research in this field. A scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As there have been no scientometric studies on wood hydrolysis, this chapter presents a scientometric study of research in wood hydrolysis. It examines the scientometric characteristics of both the sample and population data presenting the scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, keywords, and research fronts.

6. Konur, O. 2023t. Wood hydrolysis: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 115-132. Boca Raton, FL: CRC Press. 18 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in fuel cells, and in biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of bioethanol prior to bioethanol production through hydrolysis of the biomass and fermentation of resultant hydrolysates. Wood has been one of the most-studied biomasses for bioethanol production. In this context, research in the field of wood hydrolysis has thus intensified in recent years as enzymatic, chemical, hydrothermal, and to a lesser extent mechanical hydrolysis of wood has been widely researched to increase sugar and bioethanol yield. Further, on individual terms, the most prolific types of hydrolysis have been acid, steam explosion, alkaline, sulfite, H₂O₂, liquid hot water, milling, ammonia, hydrothermal in general, and ionic liquid hydrolysis. On the other hand, the most prolific wood biomasses have been hardwood and softwood and on individual terms spruce, Douglas fir, and poplar, and to a lesser extent olive tree, pine, willow, aspen, bamboo, beech, birch, and eucalyptus. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance research in this field. Although there have been a limited number of review papers on wood hydrolysis, there has been no updated review of the most-cited 25 articles in this field. Thus, this chapter presents a review of the most-cited 25 articles in the field of wood hydrolysis. Then, it discusses the key findings of these highly influential papers and comments on future research priorities in this field.

7. Konur, O. 2023u. Straw hydrolysis: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 133-155. Boca Raton, FL: CRC Press. 23 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline and diesel fuels, in fuel cells, and in biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining energy security in the supply shocks related to oil price shocks, COVID-19 pandemic, or wars in the aftermath of Russian invasion of Ukraine and COVID-19 pandemic. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol fuel prior to its production through hydrolysis and fermentation. Wheat straw and rice straw have been among the most studied biomasses for bioethanol production. In this context, the research in the field of straw hydrolysis has thus intensified in recent years. In recent years, enzymatic hydrolysis of straw combined with chemical and, to a lesser extent, hydrothermal and mechanical pretreatments of straw has been widely researched to increase the sugar and bioethanol yield. Further, on the individual terms, the most prolific types of pretreatments and hydrolysis of straw have been alkaline, acid, steam explosion, solvent, microwave, ammonia, ionic liquid, milling, H2O2, wet oxidation, and liquid hot water pretreatments. On the other hand, the most prolific straw biomass has been wheat and rice straw and, to a lesser extent, barley, sorghum, soybean, and sugarcane. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As there have been no scientometric studies on the straw hydrolysis as of May 2022, this book chapter presents a scientometric study of the research in straw hydrolysis. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, keywords, and research fronts.

8. Konur, O. 2023v. Straw hydrolysis: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 156-175. Boca Raton, FL: CRC Press. 20 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, fuel cells, and biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. Wheat straw and rice straw have been among the most studied biomass for the bioethanol production. In this context, the research in the field of straw hydrolysis has thus intensified in recent years. In recent years, enzymatic hydrolysis combined with chemical and, to a lesser extent, hydrothermal and mechanical pretreatments of straw have been widely researched to increase the sugar and bioethanol yield. Further, on the individual terms, the most prolific pretreatments of the straw have been acid, alkaline, ionic liquid, milling, and to a lesser extent ammonia, microwave, solvent, surfactant, H₂O₂, hot compressed water, liquid hot water, ozone, steam explosion, and wet oxidation pretreatments. On the other hand, the most prolific straw biomass has been wheat and rice straw and to a lesser extent corn, rye, sorghum, and sugarcane straw. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there have been a limited number of review papers on straw hydrolysis, there has been no review of the 25 most cited articles in this field. Thus, this book chapter presents a review of the 25 most cited articles in the field of straw hydrolysis. Then, it discusses the key findings of these highly influential papers and comments on future research priorities in this field.

9. Konur, O. 2023w. Cellulose hydrolysis: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 176-197. Boca Raton, FL: CRC Press. 22 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline and diesel fuels, in the fuel cells, and in the biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining the energy security in the supply shocks related to oil price shocks, COVID-19 pandemics or wars in the aftermath of Russian invasion of Ukraine, and COVID-19 pandemics. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis and fermentation of the biomass. The research in the field of cellulose hydrolysis has thus intensified in recent years as the enzymatic, chemical, and to a lesser extent hydrothermal and mechanical hydrolysis and pretreatments of cellulose have been widely researched to increase the sugar and bioethanol yield in this context. Further, on the individual terms, the most-prolific research fronts have been acid, ionic liquid, solvent, steam explosion, water, alkaline, hot compressed water, liquid hot water, microwave, ammonia, co2, surfactant, milling, and ultrasound hydrolysis and pretreatments. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As there have been no scientometric studies on the cellulose hydrolysis as of May 2022, this book chapter presents a scientometric study of the research in cellulose hydrolysis. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, keywords, and research fronts.

10. Konur, O. 2023x. Cellulose hydrolysis: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 198-213. Boca Raton, FL: CRC Press. 16 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. In this context, the research in the field of cellulose hydrolysis has thus intensified in recent years as the enzymatic and chemical hydrolysis of cellulose has been widely researched to increase the sugar and bioethanol yield at the expense of hydrothermal and mechanical hydrolysis. Further, on the individual terms, the most prolific research fronts have been acid, ionic liquid, supercritical water, solvent, alkaline, and ammonia hydrolysis. Although there have been a number of review papers on the cellulose hydrolysis, there has been no updated review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of the most-cited 25 articles in the field of the cellulose hydrolysis. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

Part 5. Hydrolysate Fermentation for Bioethanol Production 176 pp.

11. Konur, O. 2023y. Hydrolysate and substrate fermentation: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 217-241. Boca Raton, FL: CRC Press. 25 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining the energy security in the supply shocks related to oil price shocks, COVID-19 pandemics, or wars in the aftermath of the Russian invasion of Ukraine. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis and fermentation of the biomass. The research in the fields of hydrolysate and substrate fermentation has thus intensified in recent years as the microorganism and substrate metabolic engineering, fermentation inhibitors, and to a lesser extent simultaneous saccharification and fermentation (SSF), hydrolysate detoxification, fermentation microorganisms, fermentation in general, consolidated bioprocessing, and microorganism ethanol tolerance have been widely researched to increase bioethanol yield in this context. On the other hand, the most prolific types of feedstocks for the fermentation processes have been hydrolysates, agricultural residues, and to a lesser extent biomass constituents, algae, glycerol, biosyngas, wood, grass, and sugar feedstocks. Further, on the individual terms, the most prolific feedstocks have been xylose, glucose, and to a lesser extent hydrolysates in general, pentose, cellulose, corn stover, hexose, wheat straw, sugarcane bagasse. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As the recently published scientometric studies focus on a certain research front, this book chapter presents a scientometric study of the research in the hydrolysate and substrate fermentation as a whole. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, keywords, and research fronts.

12. Konur, O. 2023z. Hydrolysate and substrate fermentation: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 242-259. Boca Raton, FL: CRC Press. 18 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. The research in the field of hydrolysate and substrate fermentation has thus intensified in recent years as the microorganism and substrate metabolic engineering and to a lesser extent fermentation inhibitors, hydrolysate detoxification, fermentation in general, and simultaneous saccharification and fermentation (SSF), fermentation microorganisms, other fermentation issues, and microorganism ethanol tolerance have been widely researched to increase the bioethanol yield in this context in recent years. Further, the most prolific feedstocks for the fermentation have been hydrolysates and to a lesser extent agricultural residues, wood, biomass constituents, algae and grass. On the other hand, on the individual terms, the most prolific feedstocks have been xylose, glucose, hydrolysates in general, wheat straw, other agricultural residues, corn stover, sugarcane bagasse, and cellulose. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there has been a number of review papers on the hydrolysate and substrate fermentations, there has been no up to date review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of the most-cited 25 articles in this field. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

13. Konur, O. 2023ax. The alternative fermentation processes for the bioethanol production: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 260-283. Boca Raton, FL: CRC Press. 24 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in fuel cells, and in biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining energy security in the supply shocks related to oil price shocks, coronavirus disease 2019 (COVID-19) pandemic, or wars in the aftermath of the Russian invasion of Ukraine. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol before the bioethanol production through hydrolysis and fermentation of the biomass and hydrolysates, respectively. Research in the field of alternative fermentation processes for the bioethanol production for the separate hydrolysis and fermentation (SHF) process to improve the ethanol yield has intensified in this context in recent years. The key research front has been the simultaneous saccharification and fermentation (SSF) of the biomass and to a lesser extent consolidated bioprocessing (CBP) of the biomass, simultaneous saccharification and cofermentation (SSCF) of the biomass, continuous ethanol production (CEP) of the biomass, and continuous ethanol fermentation (CEF). Furthermore, these innovative research fields have focused on agricultural residues, wood, biomass in general, wastes, and to a lesser extent biomass constituents, grass, hydrolysates, algae, and other biomass. Furthermore, on individual terms the most prolific biomass has been corn stover, lignocellulosic biomass, wheat straw, food waste, cellulosic biomass, industrial wastes, lignocellulose, rice straw, sugarcane bagasse, corncobs, cellulose, xylose, corn, and potato. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of research in a selected research field. As the recently published scientometric studies focus on the fermentation process in general, this book chapter presents a scientometric study of research in alternative fermentation processes for bioethanol production. It examines the scientometric characteristics of both the sample and population data presenting the scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, Scopus keywords, and research fronts.

14. Konur, O. 2023ab. The alternative fermentation processes for the bioethanol production: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 284-301. Boca Raton, FL: CRC Press. 18 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates. The research in the field of the alternative fermentation processes for the bioethanol production for the separate hydrolysis and fermentation (SHF) process to improve the ethanol yield has intensified in this context in recent years. The key research fronts have been the simultaneous saccharification and fermentation (SSF) of the biomass and to a lesser extent consolidated bioprocessing (CBP) and simultaneous saccharification and cofermentation (SSCF) of the biomass. Further, these innovative research fields have focused on the agricultural residues, wood, other feedstocks at the macro scale, and in the individual terms, on the corn stover, wheat straw, and to a lesser extent rice straw, corncobs, sorghum bagasse, food wastes, grass, industrial wastes, algae, and cellulose. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there has been a number of review papers on the fermentation processes for the bioethanol production at the macro scale, there has been no review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of these most-cited 25 articles. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

15. Konur, O. 2023ac. Metabolic engineering for the bioethanol production: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 302-326. Boca Raton, FL: CRC Press. 25 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining the energy security in the supply shocks related to oil price shocks, COVID-19 pandemics, or wars in the aftermath of the Russian invasion of Ukraine starting in February 2022. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis and fermentation of the biomass and hydrolysates, respectively. The research in the field of the metabolic engineering of the microorganisms and substrates for the bioethanol production to improve the ethanol yield has intensified in this context in recent years. The key research fronts with regard to the microorganisms used in the metabolic engineering have been Saccharomyces cerevisiae and to a lesser extent Escherichia coli, microorganisms in general, Clostridium, other microorganisms, Pichia stipitis, Zymomonas mobilis, Bacillus subtilis, and Klebsiella. Further, the most-prolific substrates have been corn, grass, and cyanobacteria. On the other hand, the most-prolific feedstocks used for metabolic engineering have been hydrolysates and, to a lesser extent, biomass constituents and other feedstocks at the macroscale, while on individual terms xylose and to a lesser extent glucose, cellulose, hydrolysates in general, pentose, lignocellulose, algae, arabinose, glycerol, cellobiose, wood, agricultural residues, ethane, and other biomass. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As the recently published scientometric studies focus on the fermentation process in general, this book chapter presents a scientometric study of the research in the metabolic engineering for the bioethanol production. It examines the scientometric characteristics of both the sample and population data presenting scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, Scopus keywords, and research fronts.

16. Konur, O. 2023ad. Metabolic engineering for the bioethanol production: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 327-344. Boca Raton, FL: CRC Press. 18 pp.

The crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in the fuel cells, and in the biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol prior to the bioethanol production through the hydrolysis of the biomass and fermentation of the resulting hydrolysates, respectively. The research in the field of the metabolic engineering of microorganisms and substrates for the bioethanol production to improve the ethanol yield has intensified in this context in recent years. The key research fronts with regard to the microorganisms have been the Saccharomyces cerevisiae , Zymomonas mobilis, other microorganisms, Escherichia coli, and to a lesser extent, Pichia stipitis, while the substrates have been grass and cyanobacteria. Further, the most-prolific feedstocks have been hydrolysates and, to a lesser extent, algae, other feedstocks, and glycerol at the macroscale while on the individual terms have been xylose, glucose, and to a lesser extent, hydrolysates in general, wood, agricultural residues, grass, and biomass constituents such as cellulose. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there have been a number of review papers on the metabolic engineering of the microorganisms and substrates for the bioethanol production, there has been no review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of these most-cited 25 articles. Then, it discusses the key findings of these highly influential papers and comments on the future research priorities in this field.

17. Konur, O. 2023ae. The utilization of the Saccharomyces cerevisiae for the bioethanol production: Scientometric study. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 345-368. Boca Raton, FL: CRC Press. 24 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in fuel cells, and in biochemical production in a biorefinery context. Bioethanol fuels also play a critical role in maintaining energy security in the supply shocks related to oil price shocks, coronavirus disease 2019 (COVID-19) pandemic, or wars in the aftermath of the Russian invasion of Ukraine starting in February 2022. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol before bioethanol production through hydrolysis and fermentation of the biomass and hydrolysates, respectively. Research in the field of the utilization of Saccharomyces cerevisiae (S. cerevisiae) for bioethanol production to improve ethanol yield has intensified as the most-studied yeast in the fermentation of feedstocks to produce bioethanol in this context in recent years. The key research fronts with regard to feedstocks have been hydrolysates and to a lesser extent other feedstocks, agricultural residues, wood, and grass at the macroscale, while on individual terms they have been xylose and to a lesser extent glucose, hydrolysates in general, arabinose, lignocellulosic biomass, food waste, cellobiose, sugarcane bagasse, cellulose, rice straw, and wheat straw. However, the most prolific thematic research fronts have been hydrolysate fermentation, metabolic engineering, biomass fermentation, ethanol stress, ethanol production in general, fermentation inhibitors, and fermentation processes at the macroscale, while for the first research front they have been xylose fermentation and to a lesser extent glucose fermentation, hydrolysate fermentation in general, arabinose fermentation, and cellobiose fermentation. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. The scientometric analysis has been used in this context to inform the primary stakeholders about the current state of the research in a selected research field. As the recently published scientometric studies focus on the fermentation process in general, this book chapter presents a scientometric study of the research in the utilization of S. cerevisiae for bioethanol production. It examines the scientometric characteristics of both the sample and population data presenting the scientometric characteristics of these both datasets in the order of documents, authors, publication years, institutions, funding bodies, source titles, countries, Scopus subject categories, Scopus keywords, and research fronts.

18. Konur, O. 2023af. The utilization of the Saccharomyces cerevisiae for the bioethanol production: Review. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 369-290. Boca Raton, FL: CRC Press. 22 pp.

Crude oil-based gasoline fuels have been widely used in the transportation sector since the 1920s. However, there have been great public concerns over the adverse environmental and human impact of these fuels. Hence, biomass-based bioethanol fuels have increasingly been used in blending gasoline fuels, in fuel cells, and in biochemical production in a biorefinery context. However, it is necessary to pretreat the biomass to enhance the yield of the bioethanol before bioethanol production through hydrolysis of the biomass and fermentation of the resulting hydrolysates, respectively. The research in the field of the utilization of Saccharomyces cerevisiae (S. cerevisiae) for bioethanol production to improve the ethanol yield has intensified as the most-studied yeast in the fermentation of the feedstocks to produce bioethanol in this context in recent years. The key research fronts with regard to the feedstocks have been hydrolysates and to a lesser extent agricultural residues, wood, and grass at the macroscale and xylose, glucose, rice straw, corn stover, arabinose, cellobiose, wheat straw, and sorghum bagasse at the microscale. Furthermore, the most prolific thematic research fronts have been metabolic engineering, xylose fermentation, biomass fermentation, glucose fermentation, fermentation inhibitors, and to a lesser extent ethanol stress, other hydrolysate fermentation, and fermentation processes. However, it is essential to develop efficient incentive structures for the primary stakeholders to enhance the research in this field. Although there have been several review papers on the utilization of S. cerevisiae for bioethanol production, there has been no review of the most-cited 25 articles in this field. Thus, this book chapter presents a review of these 25 most-cited articles. Then, it discusses the key findings of these highly influential papers and comments on future research priorities in this field.

Part 6. Bioethanol fuel separation for Bioethanol Production 46 pp.

19. Chen, H.; Cai, D.; Wen, J.; Su, C.; Wang, J. (2023). Distillation separation of bioethanol: the current advances. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 393-408. Boca Raton, FL: CRC Press. 16 pp. Huidong Chen, Di Cai, Jieyi Wen, Changsheng Su, Jianghong Wang

Bioethanol fuels from abundant biomass resources via fermentation have been long considered as an important bulk chemical and sustainable biofuel in the context of the circular economy. In the bioethanol production process, an indispensable step is the downstream separation of the dilute product from water-rich fermentation broth. This separation step was proved as one of the most energy-intensive steps in the whole bioethanol process and occupied a large percentage of the production cost. To decrease the energy requirement, continuous improvement of the bioethanol separation techniques was of great necessity. Compared with other emerging bioethanol separation technologies, distillation is a time-tested method and has been widely used in industry. This chapter is focused on the distillation for bioethanol separation. In the first part, the basic property of components in the bioethanol fermentation broth was introduced followed by discussing the thermodynamic behavior and the phase equilibrium. In the second part, the current advances and technical trends in bioethanol distillation, including the selection of sequences and process intensification, were reviewed. In the third part, techno-economic analysis and life cycle assessment models for bioethanol distillation are briefly introduced.

20. Cai, D.; Si, Z.; We, H.; Zhuang, Y.; Qin, P. (2023). In situ bioethanol separation by from fermentation broth. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 409-425. Boca Raton, FL: CRC Press. 17 pp. Di Cai, Zhihao Si, Hanzhu Wu, Yan Zhuang, Peiyong Qin

Bioethanol is an important biofuel. The downstream separation is one of the most energy-intensive processes for bioethanol production, which negatively influenced the process cost and economic competitiveness. To date, a plenty of studies has been committed to establish more efficient bioethanol recovery processes for in situ product recovery (ISPR) from fermentation broth. In this chapter, principles of the ISPR techniques for bioethanol production that emerged in recent years, including gas stripping, vacuum fermentation, adsorption, liquid-liquid extraction, pervaporation, perstraction, and membrane distillation, are introduced in detail, to which the latest progress are summarized. Research trends for multistage ISPR for consolidating the bioethanol separation that is beyond the single-stage processes are also described.

21. Gomez-Castro, F.I.; Segovia-Hernández, J. G.; Rodríguez, R. R.; and Mejia, C. C. (2023). Advances and challenges in the production and purification of bioethanol using intensified processes. In Bioethanol Fuel Production Processes II: Biomass Hydrolysis, Fermentation, and Bioethanol Fuel Separation. Handbook of Bioethanol Fuels: Production and Utilization Volume 2, O. Konur, pp. 426-436. Boca Raton, FL: CRC Press. 11 pp. Fernando Israel Gómez-Castro, Juan Gabriel Segovia-Hernández, Ricardo Morales Rodríguez, Carolina Conde Mejía

Ethanol can be produced from biomass to be used either as fuel or as additive. Such product is known as bioethanol. Nevertheless, the conversion of biomass to ethanol still has several challenges. The bioethanol yields are low, and great quantities of water are required in the process. Moreover, producing anhydrous ethanol is not an easy task due to the existence of the ethanol/water azeotrope, which causes high energy requirements to achieve such high-purity product. Process intensification is a tool that may enhance the performance of the bioethanol production processes. The development of advanced technologies allows using synergetic effects between phenomena, reducing the size of the required equipment, increasing the reaction yields, and reducing the energy requirements, among other advantages. In this chapter, intensified technologies applied to bioethanol production are described, and their benefits in comparison with conventional production are pointed. Moreover, challenges and future trends in the production of bioethanol are described.