Microalgal Biofuels

Sustainable Production, Conversion, and Life Cycle Assessment

1st Edition - January 29, 2025
Imprint: Woodhead Publishing
Editors: Krishna Kumar Jaiswal, Bhaskar Singh, Amit K. Jaiswal
Language: English
Paperback ISBN:
9 7 8 - 0 - 4 4 3 - 2 4 1 1 0 - 9
eBook ISBN:
9 7 8 - 0 - 4 4 3 - 2 4 1 1 1 - 6

Microalgal Biofuels: Sustainable Production and Conversion is a comprehensive guide to the latest advancements in microalgal biofuels. The book provides systematic coverage… Read more

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Microalgal Biofuels: Sustainable Production and Conversion is a comprehensive guide to the latest advancements in microalgal biofuels. The book provides systematic coverage of the processes of biofuel production, from microalgae biomass resources to biomass conversion processes and catalytic materials. It delves into the critical topic of sustainability, addressing LCA approaches to evaluate the environmental impacts of microalgal-based biofuels. It provides practical information and guidance on the latest strategies, opportunities, and challenges in the transition to sustainable bioenergy. This is an invaluable reference for students, researchers, and industrial practitioners working on biofuels, biotechnology, bioprocess engineering, and biomass conversion.

Divided into four sections, the first section introduces the principles of microalgal biology and cultivation, including an overview of the different types of microalgae, their growth requirements, and the cultivation systems used for large-scale production. The second section explains the conversion of microalgal biomass into biofuels, including biodiesel, bioethanol, biogas, and hydrogen. Each chapter in this section covers a different biofuel pathway, highlighting the technological advancements, challenges, and opportunities for scaling up production. The third section of the book explores the sustainability aspects of microalgal biofuel production, including the use of waste streams and the integration of biofuel production with other industries. This section also covers the LCA approaches used to evaluate the environmental impacts of microalgal biofuels and the strategies for enhancing their sustainability. The fourth and final section of the book examines the commercialization and prospects of microalgal biofuels. This section covers the market potential of microalgal biofuels, the regulatory landscape, and the challenges and opportunities for the industry.

Title of Book
Cover image
Title page
Table of Contents
Copyright
Contributors
Editors
Preface
Section I. Microalgae biomass resources
Chapter 1. Introduction to microalgal biofuels
1.1 Introduction
1.2 Biofuels and their significance
1.2.1 Bioethanol
1.2.2 Biodiesel
1.2.3 Biogas
1.3 Classification of first-, second-, and third-generation biomass for biofuels
1.4 Microalgae biofuels
1.5 Processes for microalgal biofuel production
1.5.1 Mechanical methods
1.5.2 Physico-chemical methods
1.5.3 Thermochemical methods
1.5.4 Biological methods
1.6 Approaches to algal farming for biomass generation: Raceway ponds and photobioreactor
1.7 Biochemical molecules of microalgae and their applications
1.7.1 Biofuels
1.7.2 Food supplements
1.7.3 Pharmaceutical and nutraceutical products
1.7.4 Others
1.8 The biorefinery approach for biofuels production from microalgae
1.9 The transition of microalgae biomass to biofuels: Opportunities and challenges
1.10 Conclusions and future scope
Chapter 2. Strategies for bioenergy and biofuels from algae biomass
2.1 Introduction
2.2 Upstream processing
2.2.1 Impact of light-induced stress on lipid production
2.2.2 Impact of temperature stress on lipids accumulations
2.2.3 Impact of pH-enhanced lipids
2.2.4 Impact of nitrogen, phosphorus, and sulfur stress on the lipids
2.2.5 Impact of salinity on lipids production
2.2.6 Impact of metal stress
2.3 The impact of innovative alternative approaches on the production of biofuel in microalgae
2.3.1 Two-stage cultivation system
2.3.2 Genetic modifications of microalgal strain for biofuel production
2.4 Microalgal biomass conversion routes
2.4.1 Thermochemical methods
2.4.1.1 Torrefaction
2.4.1.2 Conventional torrefaction
2.4.1.3 Oxidative torrefaction
2.4.1.4 Microwave torrefaction process
2.4.1.5 Wet torrefaction process
2.4.1.6 Pyrolysis
2.4.1.7 Fast pyrolysis
2.4.1.8 Slow pyrolysis
2.4.1.9 Catalytic pyrolysis
2.4.1.10 Microwave pyrolysis
2.4.1.11 Gasification
2.4.1.12 Conventional gasification
2.4.1.13 Supercritical water gasification
2.4.2 Chemical conversion of algal biomass
2.4.2.1 Transesterification
2.4.2.2 Microalgal transesterification by acid catalysis
2.4.2.3 Enzyme catalysis
2.4.2.4 Cosolvent-mediated techniques
2.4.2.5 Novel heterogeneous nanocatalysts for microalgal transesterification
2.5 Techno-economic analysis and life cycle assessment
2.6 Multiomics approach for biofuel and bioenergy
2.7 Future perspective
2.8 Conclusion
Chapter 3. Optimization of photobioreactor and open pond systems for sustainable microalgal biomass production: Challenges, solutions, and scalability
3.1 Introduction
3.2 Cultivation systems for microalgae cultivation
3.2.1 Open cultivation systems
3.2.1.1 Open raceway ponds
3.2.1.2 Unstirred ponds
3.2.1.3 Circular ponds
3.3 Photobioreactors
3.3.1 Tubular photobioreactors
3.3.2 Flat-panel PBRs
3.3.3 Bubble-column and airlift PBRs
3.3.4 Stirred tank reactor
3.4 Open ponds versus photobioreactors
3.5 Factors affecting microalgae cultivation
3.5.1 Light
3.5.2 Temperature
3.5.3 Aeration
3.5.4 pH
3.6 Sterilization and contamination control
3.7 Scalability
3.8 Economic feasibility of OPs and PBRs
3.9 Conclusion
Chapter 4. Noncellulosic and lignocellulosic feedstocks for biofuels
4.1 Introduction
4.2 Noncellulosic feedstocks
4.2.1 Bioethanol
4.2.2 Biodiesel
4.3 Lignocellulosic feedstocks
4.3.1 Bioethanol
4.3.2 Biomethane
4.3.3 Biohydrogen
4.4 Microalgae as feedstock
4.4.1 Biodiesel
4.4.2 Bioethanol
4.4.3 Biohydrogen
4.5 Challenges
4.5.1 Noncellulosic biomass: sustainability concerns
4.5.2 Lignocellulosic biomass
4.5.3 Microalgae
4.6 Future prospects and conclusion
Chapter 5. The untapped potential of microalgae: From biomolecule synthesis to bioenergy conversion
5.1 Introduction
5.2 Microalgal biomolecules and biochemistry
5.2.1 Lipids
5.2.1.1 Fatty acids and triacylglycerols
5.2.1.2 Polyunstaturated fatty acids
5.2.1.3 Sterols
5.2.2 Carbohydrates
5.3 Genetic engineering and metabolic strategies to enhance microalgal lipids productivity
5.3.1 Metabolism of fatty acids
5.3.1.1 Kennedy pathway
5.3.2 Metabolism of polyunsaturated fatty acids (PUFAs)
5.4 Microalgal biomolecules in biofuels applications
5.4.1 Biobutanol
5.4.2 Bioethanol
5.4.3 Biomethane
5.4.4 Biodiesel
5.4.5 Biohydrogen
5.5 Challenges and future prospects
5.6 Conclusion
Chapter 6. Biorefinery approach to obtain sustainable biofuels and high-value chemicals from microalgae
6.1 Introduction
6.2 Cultivation of microalgae for biomass
6.2.1 Open pond systems
6.2.2 Photobioreactors
6.3 Harvesting of microalgae
6.3.1 Flocculation
6.3.2 Chemical flocculation
6.3.3 Physical flocculation
6.3.4 Bio-flocculation
6.4 Biofuels
6.4.1 Biodiesel
6.4.2 Bioethanol
6.4.3 Biohydrogen and biohythane
6.4.4 Bio-syngas, biochar, and bio-oil
6.4.4.1 Hydrothermal liquefaction
6.5 Microalgae as a source of biorefinery
6.5.1 Pigments
6.5.2 Proteins, peptides, and enzymes
6.5.3 Vitamins
6.5.4 Pharmaceuticals
6.5.4.1 Anticancer activity
6.5.4.2 Anti-inflammatory and antiviral activity
6.5.4.3 Antibacterial activity
6.5.5 Lipids and polyunsaturated fatty acids
6.5.6 Bioplastics
6.5.7 Environmental valuable products and environmental protection
6.5.7.1 Ecologically valuable products
6.5.7.2 Wastewater treatment
6.5.7.3 Bioremediation
6.6 Conclusion
Chapter 7. Opportunities and challenges in the transition of microalgae biomass to biofuels
7.1 Introduction
7.2 Opportunities in the transition of microalgae biomass to biofuels
7.2.1 Phototrophic cultivation
7.2.2 Heterotrophic cultivation
7.2.3 Mixotrophic cultivation
7.3 Strategies in nutrients optimization for overproduction of biomass vis-à-vis lipid production
7.3.1 Carbon
7.3.2 Nitrogen
7.3.3 Phosphorus
7.3.4 Sulfur
7.4 Strategies of temperature, light, and pH on biofuel production from microalgae
7.5 Strategies for bioenergy production from microalgal biomass
7.5.1 Thermochemical conversion
7.5.1.1 Pyrolysis
7.5.1.2 Liquefaction
7.5.1.3 Gasification
7.5.2 Biochemical conversion
7.5.2.1 Anaerobic digestion
7.5.2.2 Fermentation
7.5.2.3 Photobiological hydrogen production
7.5.3 Chemical conversion
7.6 Challenges in mass cultivation strategies for the biomass and lipid production in microalgae
7.6.1 Raceway pond
7.6.2 Flat-panel photobioreactor
7.6.3 Tubular photobioreactor
7.6.4 Vertical photobioreactor
7.7 Downstream processing
7.7.1 Harvesting
7.7.1.1 Physical methods
7.7.1.2 Chemical methods
7.7.1.3 Biological methods
7.8 Future prospects and conclusion
Section II. Biomass conversion processes
Chapter 8. Biochemical conversion and cultivation strategies for microalgae biomass: Challenges and future prospects in biofuel production
8.1 Introduction
8.2 Microalgae for biofuel production
8.3 Cultivation strategies for biomass production
8.3.1 Open pond cultivation
8.3.2 Closed photobioreactors cultivation
8.3.3 Raceway ponds cultivation
8.3.4 Hybrid cultivation systems
8.4 Biomass conversion pathways
8.4.1 Biochemical conversion
8.4.1.1 Anaerobic digestion of algal biomass
8.4.1.2 Fermentation
8.4.2 Chemical and thermochemical conversion
8.4.2.1 Transesterification
8.5 Utilization of microalgae residue
8.6 Current challenges and future prospects
8.7 Conclusion
Chapter 9. Microalgae—The future of biofuel: An in-depth analysis of thermochemical conversion, challenges, and opportunities
9.1 Introduction
9.2 Pyrolysis
9.2.1 Slow pyrolysis
9.2.2 Fast pyrolysis
9.2.3 Microwave-assisted pyrolysis
9.2.4 Catalytic pyrolysis
9.3 Gasification
9.4 Hydrothermal liquefaction
9.5 Conclusion
Chapter 10. Microalgal bio-electrochemical system and pretreatment technologies for biohydrogen production
10.1 Introduction
10.2 Working principles of and basic designs of bio-electrochemical system
10.2.1 Microbial fuel cells
10.2.2 Microbial electrolysis cells
10.3 Physical pretreatment
10.3.1 Mechanical pretreatment
10.3.2 Irradiation methods
10.3.3 Pulsed electric field
10.4 Thermal pretreatment
10.4.1 High-temperature thermal pretreatment
10.4.2 Autoclaving
10.4.3 Steam explosion
10.4.4 Freezing and thawing
10.5 Chemical pretreatment
10.5.1 Acid treatment
10.5.2 Alkali pretreatment
10.5.3 Ionic liquid treatment
10.6 Biological pretreatment
10.7 Hydrogen synthesizing enzymes in microalgal metabolism
10.7.1 Hydrogenase enzyme and their roles
10.7.2 The role of nitrogenase enzyme
10.8 Dark fermentation
10.8.1 Bio-photolysis
10.8.2 Direct bio-photolysis
10.8.3 Indirect photolysis
10.8.4 Bio-electrochemical system
10.9 Latest advancement in algal hydrogen production using bioelectrochemical system
10.10 Microalgal conversion to biohydrogen challenges and prospects
10.11 Conclusion
AI Disclosure
Chapter 11. Transforming waste: Hydrothermal and biological pathways to generate bioenergy
11.1 Introduction
11.2 Classification of the wastes
11.2.1 Food waste
11.2.2 Agricultural wastes
11.2.3 Microalgal biomass waste
11.2.4 Municipal solid waste
11.2.5 Municipal liquid waste
11.2.6 Industrial effluents
11.3 Waste conversion technologies
11.3.1 Anaerobic co-digestion
11.3.2 Hydrothermal liquefaction
11.3.3 Hydrothermal carbonization
11.3.4 Supercritical water gasification
11.4 Establishment of integrated waste valorizing techniques
11.5 Bottlenecks in the commercialization of the processes
11.5.1 Technical obstacles
11.5.2 Economic feasibility
11.5.3 Social and regulatory Acceptance
11.6 Conclusions
Chapter 12. High-value products from microalgae—Unlocking the potential for large-scale commercialization
12.1 Introduction
12.2 High-value added compounds
12.2.1 Lipid
12.2.2 Proteins
12.2.3 Pigments
12.2.4 Food/feed
12.2.5 Bioplastics
12.3 Recent advancements in the processing technologies
12.3.1 Microalgal cultivation and up-streaming technologies
12.3.1.1 Bioprospecting of potential microalgal strains
12.3.1.2 Optimization of carbon and energy sources
12.3.1.3 Nanotechnology-based growth conditions
12.3.1.4 Genetic interventions for increased HVAC production
12.3.2 Downstreaming technologies for HVAC extraction
12.3.2.1 Cell harvesting techniques
12.3.2.2 Physical methods for HVAC extraction
12.3.2.3 Chemical methods for HVAC extraction
12.3.2.4 Biological methods for HVAC extraction
12.4 Policy analyses and global market trend of microalgal HVACs
12.5 Conclusion and future perspectives
Section III. Catalytic materials for biomass to biofuel conversion
Chapter 13. Trends in biomass conversion: Exploring biochemical, thermochemical, and nanotechnological strategies for biofuel production
13.1 Introduction
13.2 Classification of biomass
13.2.1 Wood and woody biomass
13.2.2 Herbaceous biomass
13.2.3 Aquatic biomass
13.2.4 Biomass from animal and human waste
13.3 Biochemical conversion pathways
13.3.1 The process of fermentation
13.3.2 Anaerobic digestion
13.3.3 Advantages of biochemical conversion processes
13.4 Thermochemical technologies
13.4.1 Direct combustion
13.4.2 Torrefaction
13.4.3 Hydrothermal liquification
13.4.4 Pyrolysis
13.4.5 Gasification
13.5 Nanocatalysts for biomass gasification
13.5.1 Catalysts for char gasification
13.5.1.1 Effective catalysts
13.5.1.2 Role of metallic compounds
13.5.1.3 Catalyst poisoning
13.5.2 Catalytic tar cleansing
13.6 Nanocatalysts for biomass liquefaction
13.7 Nanocatalysts for biodiesel production
13.8 Conclusion and future prospective
Chapter 14. Enzymatic deconstruction of complex biomass of microalgae for organic molecules
14.1 Introduction
14.2 Biochemistry of algal biomass
14.2.1 Carbohydrates in algal biomass
14.2.2 Lipids in algal biomass
14.3 Pretreatment of algal biomass
14.3.1 Physical pretreatment
14.3.1.1 Milling
14.3.1.2 Extrusion
14.3.1.3 Microwave
14.3.1.4 Sonication or ultrasonication
14.3.1.5 Pulsed electric field
14.3.2 Physicochemical pretreatment
14.3.2.1 Hydrothermal
14.3.2.2 Pressurized liquid extraction
14.3.2.3 Supercritical fluids extraction
14.3.2.4 Hydrothermal carbonization
14.3.2.5 Chemical pretreatment
14.3.2.6 Green pretreatments
14.4 Enzymatic deconstruction of algal biomass
14.4.1 Enzymatic pretreatment of algal biomass
14.4.1.1 Enzymatic conversion of algal polysaccharides to sugars
14.4.2 Enzymatic conversion of lipids in algal biomass to biodiesel
14.5 Challenges and opportunities
14.5.1 Challenges in enzymatic deconstruction of algal biomass
14.5.1.1 Future directions for enzyme-assisted deconstruction of algal biomass
14.6 Conclusion
Chapter 15. Catalytic materials for thermochemical conversion processes for microalgal biofuel production
15.1 Introduction
15.2 Catalysts used in thermochemical energy conversion processes
15.2.1 Pyrolysis process
15.2.2 Hydrothermal carbonization
15.2.3 Hydrothermal liquefaction
15.2.4 Hydrothermal gasification
15.2.5 Biomass chemical looping gasification
15.2.6 Fischer–Tropsch process
15.3 Conclusion
Chapter 16. Enhancing lipid productivity in microalgae: Novel approaches for sustainable biofuel production
16.1 Introduction
16.2 Specific algal strains selection
16.3 Integrated algal cultivation system
16.4 Co-cultivation and consortia systems
16.4.1 Microalgae-microalgae co-cultivation
16.4.2 Microalgae-bacteria co-culture strategy
16.4.3 Microalgae-fungi co-culture strategy
16.5 Nutrient recycling
16.5.1 Liquid digestate from anaerobic digestion
16.5.2 CO2 recycling to boost algal productivity
16.6 Genetic engineering
16.7 Software tools for scale-up of algal biofuel production
16.7.1 Specify software tools for algal biofuel scale-up
16.7.2 Strain selection and genetic engineering
16.7.3 Cultivation process optimization
16.7.4 Harvesting and dewatering
16.7.5 Downstream processing
16.8 Automation and monitoring
16.9 Challenges in microalgal bioenergy production
16.10 Future perspectives
16.11 Conclusions
Section IV. Sustainability in algae biofuel production
Chapter 17. Positive potentials of microalgae-derived biofuels on environmental sustainability
17.1 Introduction
17.2 Potential environmental factors for algal culture
17.3 Water footprint and nutrient cycle
17.3.1 Water use in algal culture
17.4 Potential environmental risks of algal biofuel production
17.4.1 Nutrient pollution
17.4.2 Impacts on biodiversity
17.4.3 Microalgae culture-mediated waterborne pathogenicity
17.4.4 Cyanobacteria (blue-green algae)
17.4.5 Bacterial and viral pathogens
17.5 Minimizing risks associated with waterborne pathogens in microalgae culture and strategies for a safer environment
17.5.1 Maintain a controlled environment
17.5.2 Monitor culture quality
17.5.3 Select resistant algal strains
17.5.4 Enhancing microalgae culture resilience through extremophile species selection
17.6 Land usage in microalgae production
17.6.1 Assessing land usage: A comparative study of microalgae biofuel and energy crops
17.6.2 Case study 1
17.6.3 Case study 2
17.6.4 Optimizing microalgae biofuel production efficiency and land utilization
17.7 Environmental assessment of downstream processes
17.7.1 Harvesting of microalgae
17.7.1.1 Centrifugal harvesting
17.7.1.2 Filtration harvesting
17.7.1.3 Flocculation
17.7.1.4 Harvesting of microalgae through floatation
17.7.2 Dewatering
17.7.3 Lipid extraction
17.8 Downstream process of microalgal biofuel
17.8.1 Noncatalytic transesterification
17.8.2 Enzymatic transesterification
17.8.3 Sustainable biodiesel production: An eco-friendly approach
17.8.4 Use of sustainable algae cultivation
17.8.5 Optimized extraction
17.8.6 Catalysts
17.8.7 Methanol or ethanol
17.8.8 Energy efficiency
17.8.9 Recycling and waste management
17.9 Life cycle assessment of microalgae biofuel production
17.9.1 GHG emissions in microalgae biofuel production
17.9.2 Cultivation system
17.9.3 Harvesting and drying
17.9.4 Lipid extraction and conversion
17.9.5 Feedstock
17.9.6 Comparative analysis of greenhouse gas emissions and net energy in diesel and biodiesel fuels
17.10 Energy efficiency and renewable resource utilization
17.10.1 Energy efficiency in microalgae cultivation
17.10.2 Renewable energy sources for algal cultivation
17.10.3 Waste stream utilization
17.10.4 Harvesting and processing efficiency
17.10.5 Co-product utilization
17.11 Conclusion and future outlook
Chapter 18. Microalgal biofuels production and advances in sustainable applications
18.1 Introduction
18.2 Biofuels derived from microalgae
18.2.1 Bioethanol
18.2.2 Biodiesel
18.2.3 Bio-crude oil
18.2.4 Pyrolysis oil
18.2.5 Bio-jet fuel or bio-aviation fuel
18.2.6 Biomethane
18.2.7 Biohydrogen
18.2.8 Bioelectricity
18.3 Processes of microalgal biofuels production
18.3.1 Thermochemical conversion
18.3.1.1 Hydrothermal liquefaction
18.3.1.2 Gasification
18.3.2 Biochemical conversion
18.3.2.1 Fermentation
18.3.2.2 Microalgal microbial fuel cell
18.3.3 Chemical conversion
18.3.3.1 Transesterification
18.4 Potential benefits of microalgae-based biofuels
18.5 Challenges and future outlooks
18.5.1 Microalgal biodiesel
18.5.2 Microalgal bioethanol
18.5.3 Microalgal biomethane
18.5.4 Microalgal bio-crude oil
18.5.5 Microalgal biohydrogen
18.5.6 Microalgal pyrolysis oil
18.5.7 Microalgal bio-jet fuel or bio-aviation fuel
18.6 Conclusion
Chapter 19. Climate change mitigation potential of algae biofuels
19.1 Introduction
19.2 Carbon sequestration by algae
19.2.1 Direct HCO3 uptake by the algae
19.2.2 Active transport of carbon dioxide (CO2)
19.2.3 Carbonic anhydrase
19.3 Crucial role of algae biofuel on terrestrial and marine ecosystem
19.4 Mitigation potential of algae over ocean acidification
19.5 Algae-based carbon offset programs
19.6 Microalgae-based carbon capture and storage (CCS): Integrating physico-chemical, biological, and geological approaches
19.7 Renewable energy sources in climate change mitigation
19.7.1 Fossil fuel emissions and global warming
19.7.2 Global shift toward biofuels
19.7.3 Microalgae as a sustainable biofuel source
19.7.4 Microalgae in comparison to traditional energy sources
19.8 Microalgae based biofuel for climate-resilient waste management and pollution mitigation
19.9 Life cycle analysis of algae biofuel production
19.9.1 Environmental impacts of algae biofuel
19.9.1.1 Energy use
19.9.1.2 Biodiversity
19.9.2 Reduction of greenhouse gases through algal biofuels
19.9.3 Algae biofuels in global climate agreements
19.9.4 Bio-capture of carbon by microalgae
19.10 Conclusion
Chapter 20. Sustainability certifications and standards for algae biofuel production
20.1 Introduction
20.2 Considerations in sustainability certifications of algae biofuel production
20.3 Evaluating the ecological and environmental impacts of land-based and sea-based algae biofuel production
20.3.1 Land-based algae biofuel production
20.3.1.1 Nutrient opportunities in land-based algae biofuel production
20.3.1.2 Risks associated with land-based algae biofuel production
20.3.2 Sea-based algae biofuel production
20.3.2.1 Opportunities in sea-based algae biofuel production
20.3.2.2 Risks in sea-based algae biofuel production
20.4 Enhancing carbon capture efficiency in algae-based biofuel production: Advantages, challenges, and future perspectives
20.5 Obstacles and potential hazards linked to CO2 in algae cultivation
20.5.1 A variety of greenhouse gases present in combustion gas: Prospects for algae cultivation
20.5.2 Potential hazards related to greenhouse gas emissions in the production of algae biofuels
20.6 Water usage in the production of algae-based biofuels potential: Drawbacks and prospects
20.6.1 Opportunities
20.6.2 Potential hazards related to water usage in the production of algae biofuels
20.7 Genetically modified organisms in the production of algae-based biofuels: Prospects and potential risks
20.7.1 Opportunities
20.7.2 Risks
20.8 Potential hazards associated with the use of genetically modified organisms in the production of algae biofuels
20.8.1 Key challenges
20.9 Adapted sustainability criteria for algae biofuel production in developing nations
20.9.1 Opportunities
20.9.2 Challenges and observations
20.10 Risks associated with algae biofuel production in developing countries
20.10.1 Forced displacement and social equity
20.10.2 Environmental and resource impacts
20.10.3 Labor rights and environmental protections
20.10.4 Knowledge gaps in algae technology for sustainable applications
20.10.5 Economic viability
20.10.6 Environmental safety
20.10.7 Effects on local ecosystem
20.11 Conclusions and prospects
Chapter 21. Microalgal biofuels exploration—Current status, technological innovations, regulatory frameworks, and sustainability challenges: A case study
21.1 Introduction
21.2 Policy and regulatory landscape
21.2.1 Case study: Biofuel policy of Brazil
21.2.2 Case study: Biofuel policy of U.S.
21.2.3 Case study: Biofuel policy of India
21.3 Efficiency metrics and sustainability standards
21.3.1 Efficiency metrics in microalgal biofuel production
21.3.1.1 Biomass productivity
21.3.1.2 Lipid productivity
21.3.1.3 Biofuel yield
21.3.1.4 Carbon sequestration efficiency
21.3.1.5 Water use efficiency
21.3.1.6 Land use efficiency
21.3.1.7 Energy return on investment
21.3.1.8 Nutrient use efficiency
21.3.1.9 Harvesting and extraction efficiency
21.3.2 Environmental Impact Assessment: significance of Sustainability Standards
21.3.3 Analyzing cost-effectiveness in microalgal Biofuels
21.4 High blending mandates
21.4.1 Regional variations in high Blending mandates
21.4.2 Effects on market dynamics
21.4.3 Impact on production strategies
21.4.4 Sustainability implications of high Blending
21.5 Industrial perspective
21.5.1 Challenges faced by microalgal Biofuel producers
21.5.2 Innovation in production strategies
21.5.2.1 Utilizing genetic engineering to enhance the biosynthesis of a specific cellular component
21.5.2.2 Advancement in economical and efficient cell disruption techniques
21.5.2.3 Exploration of substitutes for organic solvents in biorefinery development
21.5.2.4 Conversion of proteins into biofuels by manipulating nitrogen flux through engineering
21.6 Utilization of wasteland and wastewater
21.6.1 Case study of the U.S. For microalgae-based biofuel production using wastewater
21.6.2 Case study of Brazil for microalgae-based biofuel production using wastewater
21.7 Conclusion
Chapter 22. Application of biosynthesized nanocatalysts in microalgae biofuel conversion processes: Challenges, technological advances, and environmental impacts
22.1 Introduction
22.2 Nanomaterial in microalgal biofuels processes
22.3 Biosynthesis of nanomaterials and nanocatalysts
22.4 Microalgal biofuels and production processes
22.4.1 Thermochemical conversion
22.4.1.1 Direct combustion
22.4.1.2 Gasification
22.4.1.3 Pyrolysis
22.4.1.4 Thermochemical liquefaction
22.4.1.5 Challenges, technological advances, and environmental impact of the thermochemical conversion process
22.4.2 Biochemical conversion
22.4.2.1 Anaerobic digestion
22.4.2.2 Photobiological hydrogen production
22.4.2.3 Microalgal biomass-to-biodiesel
22.5 Role of biosynthesized nanocatalysts in microalgal biofuel processes
22.6 Performance, environmental, and economic impact of the nanocatalyst in the production of microalgae biofuels
22.7 Challenges and future outlooks
22.8 Conclusion
Chapter 23. Advancing sustainability: Microalgae biofuels in the circular bioeconomy
23.1 Introduction
23.2 Comparing microalgae to conventional oil crops
23.3 Microalgae biofuels production
23.3.1 Strain selection
23.3.2 Upstream processing
23.3.2.1 Nutrient requirements and recycling
23.3.3 Downstream processing
23.3.3.1 Biomass harvesting and dewatering
23.3.3.2 Biomass pretreatment or cell disruption
23.3.3.3 Lipid extraction from biomass
23.3.3.4 Biofuel conversion technologies
23.3.3.5 Recovery of co-products or biomass valorization
23.4 Opportunities and challenges of microalgae biofuels
23.4.1 Advantages
23.4.2 Challenges and limitations
23.4.2.1 Technological and economic challenges
23.4.2.2 Sustainability challenges
23.5 Environmental impacts
23.5.1 Carbon footprint and GHG emission reduction
23.5.2 Water- and land-use efficiency
23.5.3 Biodiversity and ecological considerations
23.6 Economic and social implications
23.6.1 Market potential and competitiveness
23.6.2 Employment opportunities
23.6.3 Socioeconomic impact on local communities
23.7 Technological advancements and innovations
23.8 Regulatory and policy landscape of microalgae biofuels
23.8.1 Current regulations and incentives
23.8.2 Environmental and safety standards
23.8.2.1 Environmental standards
23.8.2.2 Safety standards
23.8.2.3 Sustainability certification and labeling
23.8.3 Policy recommendations for promoting microalgae biofuels
23.9 Future perspectives
23.10 Conclusion
Chapter 24. Exploration of marine microalgae as sustainable feedstock for lipid extraction and biofuel production
24.1 Introduction
24.2 Lipid extraction techniques from marine microalgae
24.2.1 Mechanical/physical methods
24.2.2 Chemical methods
24.3 Types of biofuel production from microalgal lipids
24.3.1 Biodiesel
24.3.2 Pyrolysis oil
24.4 Green microalgae in biofuel production
24.5 Advances in cultivation strategies for enhanced lipid production
24.6 Future prospects and challenges in marine microalgae-based biofuel
24.7 Conclusion
Chapter 25. Exploring the conversion technologies and economic viability of biofuel production from waste feedstocks
25.1 Introduction
25.2 Feedstocks for biofuel production
25.2.1 Agricultural waste residue
25.2.2 Forestry biomass
25.2.3 Municipal solid waste
25.2.4 Waste cooking oil
25.2.5 Algal biomass
25.3 Bioenergy conversion technologies
25.3.1 Gasification
25.3.2 Torrefaction
25.3.3 Liquefaction
25.3.4 Pyrolysis
25.3.5 Anaerobic digestion
25.3.6 Alcoholic fermentation
25.3.7 Transesterification
25.4 Financial and economic aspect
25.5 Biofuel policy
25.6 Conclusion
Chapter 26. Potential transformation of biowaste generated in religious institutions through various conversion techniques into carbon-neutral zero-waste biofuel
26.1 Introduction
26.2 Role of microalgae in waste conversion
26.3 Biomass waste and types of bio-wastes
26.3.1 Lignocellulosic biomass waste
26.3.2 Organic solid waste: A diverse feedstock-
26.3.3 Liquid biomass waste: A fluid resource
26.4 Waste to energy conversion processes
26.4.1 Thermochemical methods: Unlocking energy through heat
26.4.2 Biochemical methods: Microorganisms as waste transformers
26.4.3 Solid organic waste conversion: Turning waste into valuables
26.4.4 Liquid waste conversion: Tapping into liquid resources
26.5 The imperative of waste biorefineries
26.5.1 Organic waste biorefineries: Unlocking value from food and agricultural waste
26.5.2 Lignocellulosic biomass waste biorefineries: a sustainable path for biofuels
26.6 Integration of biorefinery system
26.6.1 Integration by feedstocks: diversifying resource inputs
26.6.2 Integration by products, byproducts, and waste: minimizing waste, and maximizing value
26.6.3 Integration by platforms: expanding the toolkit
26.6.4 Integration by process: enhancing efficiency through synergy
26.6.5 Integration by industries: bridging sectors for sustainability
26.7 Future scope
26.8 Conclusion
Chapter 27. Eco-friendly biofuels derived from microalgae—Production processes: The future of renewable energy
27.1 Introduction
27.2 Microalgae cultivation strategies for the cellular lipids and biodiesel production
27.2.1 Phototrophic cultivation
27.2.1.1 Sources of light
27.2.1.2 Light emitting diodes
27.2.1.3 Natural sunlight
27.2.1.4 Combination of OF-solar/multi-LED with solar panel/wind power generator
27.2.2 Heterotrophic cultivation
27.2.3 Mixotrophic mode
27.2.4 Photoheterotrophic
27.2.5 Lipid extraction
27.2.5.1 Lipid extraction methods
27.2.6 Transesterification for the production of biodiesel
27.3 Biogas production from microalgae
27.3.1 Anaerobic digestion of microalgae biomass
27.3.2 Techniques for enhancing anaerobic digestion
27.3.3 Pretreatment methods
27.3.4 Co-digestion of microalgal biomass
27.3.5 Starvation of nutrients for the production of biogas
27.4 Biohydrogen production from microalgae
27.4.1 Biophotolysis for the production of microalgae H2
27.4.2 Production of indirect photolysis H2
27.4.3 Microalgae biomass fermentation to produce DF-H2 and PF-H2
27.4.4 Photofermentation
27.4.5 Dark fermentation
27.4.6 Photofermentation-dark fermentation-H2 synthesis
27.5 Conclusion and future perspectives
Index

Krishna Kumar Jaiswal

Dr. Krishna Kumar Jaiswal obtained his Ph.D. in Green Energy Technology and postdoctoral experiences with a broad area of research in bioenergy and biofuels. He is working as an Assistant Professor at Pondicherry University, India. Dr. Krishna's research and teaching focus on bioprocess engineering, nanotechnology, and biofuels technologies in the Department of Green Energy Technology. He is actively researching and developing new technologies for bioprocessing and biofuels. He is also a subject expert for the National Testing Agency (Govt. of India), India. He has published over 65⁺ research papers in reputed journals and is an active life member of several renowned scientific societies, an editorial board member, and a reviewer of several reputed scientific journals. He also serves as a member of Boards of Studies, various Doctoral Committees, and other Administrative Positions for different Universities.

Affiliations and expertise

Assistant Professor, Pondicherry University (A Central University), India

Bhaskar Singh

Dr. Bhaskar Singh received his Ph.D. from the Indian Institute of Technology (BHU), Varanasi, UP, India, in 2010. He also holds an M. Phil. from Pondicherry (Central) University, India, with a gold medal (2006). He is currently serving as an Assistant Professor at the Centre for Environmental Sciences, Central University of Jharkhand, Ranchi, India. Dr. Singh is currently engaged in teaching in the thrust areas of environmental sciences like environmental earth science, natural resources, environmental chemistry, environmental pollution monitoring and, control technologies, etc. He is a reviewer of several international journals, viz., Fuel, Renewable Energy, and Renewable & Sustainable Energy Reviews. His current interests lie in the application of algal biomass for biodiesel synthesis, development of heterogeneous and green catalysts, and corrosion aspects of biodiesel fuel. He has published more than 40 research and review papers in peer-reviewed and high-impact international journals and 14 book chapters by international publishers. He has co-edited & co-authored 3 books.

Affiliations and expertise

Associate Professor, Department of Environmental Sciences, Central University of Jharkhand, Ranchi, Jharkhand, India

Amit K. Jaiswal

Dr. Amit K. Jaiswal is an esteemed academic and researcher currently serving as a Lecturer at the School of Food Science and Environmental Health, Technological University Dublin (TU Dublin)—City Campus, Ireland. Recognised globally for his scholarly contributions, Dr Jaiswal has been recognised among the top 1% of the world’s most cited academics in 2023 and 2024 by Clarivate Analytics, a distinction given to researchers who have demonstrated exceptional influence in their fields over the past decade. In addition, Stanford University has listed him among the top 2% of scientists worldwide for four consecutive years (2021–24). Dr Jaiswal’s research focuses on converting lignocellulosic biomass and algae (micro- and macroalgae) into biofuels, biomaterials, and biochemicals through innovative process development, techno-economic analysis, and life cycle assessment. He brings extensive expertise in bio-based materials, such as lignin and microcellulose/nanocellulose, and their applications in sustainable food packaging, water purification, and adhesives. His proficiency in green extraction techniques, including deep eutectic solvents (DES) and ultrasound-assisted processes, enables the valorisation of agri-food biomass into high-value products. With more than 125 peer-reviewed publications, 50 book chapters, and five edited books, Dr. Jaiswal’s contributions to scientific literature have significantly impacted food science and biotechnology. His work has received over 10,000 citations, with an h-index exceeding 50. He also serves on the editorial boards of key international journals, including Food Quality and Safety (Oxford University Press), Foods, Biomass (MDPI) and JSFA Reports (Wiley).

Affiliations and expertise

Centre for Sustainable Packaging and Bioproducts (CSPB), Technological University Dublin, Ireland

Life Sciences

Physical Sciences & Engineering

Social Sciences & Humanities

Health

Microalgal Biofuels

Sustainable Production, Conversion, and Life Cycle Assessment

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