Alok Kumar Patel, PhD, is working as a senior researcher in Biochemical Process Engineering, Luleå University of Technology, Lulea, Sweden to produce nutraceuticals from oleaginous microalgae. He finished his master's degree in biotechnology in 2011 and joined as a research assistant in Food Borne Infection Surveillance Unit, (Global Disease Detection India Center) CDC, USA in collaboration with National Center for Disease Control, Ministry of Health & Family Welfare, Government of India. He got his PhD in Biotechnology from IIT Roorkee in 2017. His research interest is mainly focused on the development of biotechnological processes for conversion of organic matter to bioenergy, biofuels and biochemicals, process optimization, pretreatment of biomass, nutraceuticals and value-added products from microorganisms, and biorefineries.

Leonidas Matsakas, PhD, is working as an assistant professor in the Biochemical Process Engineering group at Luleå University of Technology. He received his PhD in Biotechnology from the school of Chemical Engineering at National Technical University of Athens in 2015. After that, he joined the Biochemical Process Engineering group of LTU as postdoc fellow and later became senior lecturer at the same group. His research interest is focused on developing biomass biorefinery processes, inclusing establishing novel pretreatment and fractionation technologies for the fractionation of lignocellulosic biomass to cellulose, hemicellulose and lignin and the conversion of these streams to biofuels, biobased chemicals and biomaterials via biochemical and thermochemical routes.

1 Introduction to Essential Fatty Acids 1Alok Patel, Ulrika Rova, Paul Christakopoulos and Leonidas Matsakas 1.1 Introduction 2 1.2 Biosynthesis of PUFAs 4 1.3 Sources of Essential Fatty Acids and Daily Intake Requirement 5 1.4 Biological Role of Essential Fatty Acids 7 1.4.1 Effect on Cell Membrane Structure 7 1.4.2 Impact on Vision 9 1.4.3 Brain Function 9 1.4.4 Biosynthesis of Lipid Mediators 10 1.4.5 Effect of Omega Fatty Acids on the Regulation of Gene Expression 10 1.5 Effect of Essential Fatty Acid on Human Health (Disease Prevention and Treatment) 10 1.5.1 Neonatal Development 10 1.5.2 Gestation and Pregnancy 11 1.5.3 Cardiovascular Disease 11 1.5.4 Cancer Inhibition 12 1.5.5 Rheumatoid Arthritis 12 1.5.6 Effect on Suicide Risk in Mood Disorders 12 1.6 Concluding Remarks 12 References 13 2 Nutraceutical Fatty Acid Production in Marine Microalgae and Cyanobacteria 23Anders K. Nilsson, Carlos Jiménez and Angela Wulff 2.1 Introduction 24 2.2 Fatty Acid Synthesis 26 2.3 Glycerolipid Synthesis and Lipid Accumulation 30 2.4 Current LC-PUFA Sources and the Potential Benefits of Using Marine Microalgae 32 2.5 Nutraceutical Fatty Acids in Marine Microalgae and Species of Interest 35 2.5.1 ¿-Linolenic Acid (18:3 n-3, ¿9,12,15) 37 2.5.2 Stearidonic Acid (18:4 n-3, ¿6,9,12,15) 38 2.5.3 Eicosanoid Acid (EPA, 20:5 n-3, ¿5,8,11,14,17) and Docosahexaenoic Acid (DHA, 22:6 n-3, ¿4,7,10,13,16,19) 38 2.5.4 Docosapentaenoic Acid (22:5 n-3, ¿7,10,13,16,19) 39 2.5.5 ¿-Linolenic Acid (18:3 n-6, ¿6,9,12) 40 2.5.6 Arachidonic Acid (20:4 n-6, ¿5,8,11,14) 41 2.6 Autotrophic and Heterotrophic Cultivation 42 2.7 Cultivation from Laboratory to Industrial Scale 43 2.8 Optimizing Growth Condition to Promote Lipid Accumulation and Desired FA Profiles 48 2.8.1 Temperature Effect 49 2.8.2 Irradiance 50 2.8.3 Growth Rate 52 2.8.4 Nitrogen and Phosphorous 52 2.8.5 Co2 53 2.8.6 Salinity 54 2.9 Genetic Engineering to Promote Lipid Accumulation and Tailoring of Fatty Acid Profiles 54 2.10 Conclusions 56 2.11 Acknowledgements 57 References 57 3 Production of PUFAs as Dietary and Health Supplements from Oleaginous Microalgae Utilizing Inexpensive Renewable Substrates 77Dimitra Karageorgou, Georgios Bakratsas and Petros Katapodis 3.1 Introduction 78 3.2 PUFAs as Dietary and Health Supplements 79 3.3 Microalgae as Source of PUFAs 82 3.4 Systems for Microalgal Cultivation 89 3.5 Use of Alternative Substrates for Microalgal Growth 90 3.6 Factors that Affect the Heterotrophic and/or Mixotrophic Cultures 97 3.7 Conclusions 101 3.8 Future Perspectives 101 3.9 Acknowledgements 102 References 102 4 Lipid and Poly-Unsaturated Fatty Acid Production by Oleaginous Microorganisms Cultivated on Hydrophobic Substrates 115Markella Tzirita, Bríd Quilty and Seraphim Papanikolaou 4.1 Lipid Production (Single Cell Oil) 116 4.2 Lipid Biodegradation and Synthesis 118 4.3 Hydrophobic Substrates 122 4.3.1 Waste Fats, Oils and Grease (FOG) 122 4.3.2 Olive-Mill Wastewater (OMW) 123 4.4 Oleaginous Microorganisms 124 4.5 Conclusions 127 References 136 5 Overview of Microbial Production of Omega-3-Polyunsaturated Fatty Acid 145Farha Deeba, Kukkala Kiran Kumar and Naseem A. Gaur 5.1 Introduction 145 5.2 Microbial Sources of ¿-3 PUFA 146 5.3 ¿-3 PUFA Biosynthesis in Microbial Cells 149 5.3.1 Aerobic Desaturase and Elongase Pathway 151 5.3.2 Anaerobic Polyketide Synthase (PKS) Pathway 153 5.4 Factors Affecting ¿-3 PUFA Production 154 5.4.1 Temperature 154 5.4.2 pH 155 5.4.3 Aeration 155 5.4.4 Media Composition 155 5.4.5 Incubation Time 156 5.5 Stabilization of ¿-3 PUFA 156 5.6 Conclusions 157 References 157 6 Autotrophic Cultivation of Microalgae for the Production of Polyunsaturated Fatty Acid 165Pallavi Saxena, Mukesh Kumar and Harish 6.1 Introduction 165 6.2 Importance of PUFAs 170 6.3 Biosynthesis of PUFA in Autotrophic Algae 171 6.4 Harvesting of Algae and Extraction of Fatty Acids 173 6.5 Metabolic Engineering Towards Increasing Production of PUFA's by Algae 175 6.6 Conclusion 178 6.7 Acknowledgement 178 References 178 7 Production of Omega-3 and Omega-6 PUFA from Food Crops and Fishes 187Km Sartaj and R. Prasad 7.1 Introduction 188 7.2 PUFA as a Dietary Supplement 189 7.2.1 Omega-3 (n-3) Fatty Acids 189 7.2.2 Omega-6 (n-6) Fatty Acids 190 7.2.3 Health Aspects and Physiological Functions of PUFA 190 7.3 Biosynthesis and Metabolism of PUFA 191 7.4 Potential Commodities for PUFA Production 193 7.4.1 Food Crops 193 7.4.1.1 Soybean Seeds 197 7.4.1.2 Rapeseed 197 7.4.1.3 Safflower 198 7.4.1.4 Sesame and Linseed 198 7.4.1.5 Sunflower 198 7.4.2 Transgenic Plants 198 7.4.3 Fishes 198 7.4.3.1 Fish Bioecology and Lipid Content 199 7.5 Alternate Sources of PUFA 200 7.6 Future Avenues 200 7.7 Conclusion 203 References 203 8 The Role of Metabolic Engineering for Enhancing PUFA Production in Microalgae 209Neha Arora 8.1 Introduction 209 8.2 LC-PUFA Biosynthesis in Microalgae 212 8.2.1 Conventional Aerobic Pathway 212 8.2.2 Anaerobic Pathway 214 8.3 Identification and Characterization of Enzymes Involved in PUFA Synthesis 214 8.4 Metabolic Engineering for Enhancing the LC-PUFA Production in Microalgae 215 8.5 Conclusion and Future Perspective 222 References 223 9 Health Perspective of Nutraceutical Fatty Acids; (Omega-3 and Omega-6 Fatty Acids) 227Sneha Sawant Desai and Varsha Kelkar Mane 9.1 Introduction 228 9.1.1 Biochemistry of Fatty Acids 228 9.1.2 Overview of Fatty Acid Synthesis 231 9.1.3 Strategies for PUFA Accumulation in Microalgae 232 9.2 Health Benefits of PUFA 234 9.2.1 Omega-6 Fatty Acids 234 9.2.1.1 Linoleic Acid (LA) 234 9.2.1.2 ¿-Linolenic Acid (GLA) 234 9.2.1.3 Arachidonic Acid (ARA) 235 9.2.2 Omega-3 Fatty Acids 236 9.2.2.1 Alpha-Linolenic Acid (ALA) 236 9.2.2.2 Stearidonic Acid (SDA) 237 9.2.2.3 Docosahexanoic Acid (DHA) 237 9.2.2.4 Eicosapentaenoic Acid (EPA) 239 9.3 Conclusion 240 References 241 10 Extraction and Purification of PUFA from Microbial Biomass 249Amit Kumar Sharma, Venkateswarlu Chintala, Praveen Ghodke, Parteek Prasher and Alok Patel 10.1 Introduction 250 10.2 Biochemical Composition of Microalgae 251 10.2.1 Carbohydrates 251 10.2.2 Proteins 252 10.2.3 Lipids 252 10.3 Microalgae as a Source of Polyunsaturated Fatty Acids 253 10.4 Composition of PUFAs in Microbial Biomass 254 10.5 Methods of Lipid Extraction from Microbial Biomass 255 10.5.1 Microalgae Cell Disruption Methods 256 10.5.1.1 Mechanical Cell Disruption Methods 257 10.5.1.2 Non-Mechanical Cell Disruption Methods 260 10.5.2 Lipid Extraction Methods 260 10.5.2.1 Mechanical Extraction Method 261 10.5.2.2 Solvent Extraction Methods 261 10.5.2.3 Green Solvents Extraction Methods 264 10.5.2.4 Supercritical Extraction Method 265 10.6 Purification and Enrichment of PUFAs 266 10.6.1 Low-Temperature Crystallization Enrichment 270 10.6.2 Urea Complexation 270 10.6.3 Distillation Method 271 10.6.4 Enzymatic Purification 271 10.6.5 Chromatographic Separation 272 10.6.6 Supercritical Fluid Fractionation (SFF) 273 10.7 Concluding Remarks 273 References 274 11 Market Perspective of EPA and DHA Production from Microalgae 281Jyoti Sharma, Pampi Sarmah and Narsi R Bishnoi 11.1 Introduction 281 11.2 Categories of Omega-3 Fatty Acids and Their Health Benefits 283 11.3 Brain Development 284 11.4 Cardiovascular Diseases 285 11.5 Present Sources of Omega-3 PUFAs 286 11.6 Why Microalgae? 287 11.7 Factors Affecting Growth and Fatty Acid Composition of Microalgae 289 11.8 Algal Oil Extraction, Purification and Its Refining Techniques 291 11.9 Microalgae as a Boon for Long-Chain Omega-3 PUFAs 292 References 294 12 Oleaginous Microalgae - A Potential Tool for Biorefinery-Based Industry 299Riti Thapar Kapoor 12.1 Introduction 299 12.2 Industrial Applications of Microalgae 302 12.3 Use of Microalgae as Biofertilizer 302 12.4 Microalgae as a Food Component 303 12.5 Microalgae as a Nutraceutical 303 12.6 Pigments and Carotenoids 304 12.7 Phycobilins 305 12.8 Fatty Acids 305 12.9 Animal Nutrition 306 12.10 Safety Related Issues Related to Microalgal Nutraceuticals 307 12.11 Application in Pharmaceutical Industry 307 12.12 Utilization of Microalgae in Cosmetics Production 308 12.13 Microalgal Application in Wastewater Treatment 308 12.14 Factors Affecting Lipid Production in Microalgae 309 12.14.1 Light Intensity 309 12.14.2 Temperature 309 12.14.3 Nutrient Availability 310 12.14.4 Salinity Stress 310 12.14.5 Metal Stress 313 12.15 Application of Microalgae in Biofuel Production 313 12.15.1 Advantages of Using Microalgae for Biofuel Production 313 12.16 Biodiesel 315 12.17 Biogas 315 12.18 Hydrogen 315 12.19 Biosyngas 316 12.20 Ethanol 316 12.21 Cultivation of Microalgae for Biofuel Production 316 12.21.1 Open Microalgal System 316 12.21.2 Closed Microalgal System 317 12.21.3 Hybrid Microalgal System 317 12.22 Current Research Status in India 317 12.23 Concluding Remarks and Future Prospectives 318 12.24 Acknowledgements 318 References 318 Index 331