Algal Biorefineries and the Circular Bioeconomy

Industrial Applications and Future Prospects

Shashi Kant Bhatia, Sanjeet Mehariya, Obulisamy Parthiba Karthikeyan, OBULISAMY PARTHIBA KARTHIKEYAN

• Publisher: CRC Press
• Year: 2022
• eBook ISBN: 9781000562767
• Edition: 1
• Topic: Medicine
• Subtopic: Biotechnology in Medicine

"Algae are mysterious and fascinating organisms that hold great potential for discovery and biotechnology."

—Dr. Thierry Tonon, Department of Biology, University of York

"Science is a beautiful gift to humanity; we should not distort it."

—A.P.J. Abdul Kalam

In this book, we emphasise the importance of algal biotechnology as a sustainable platform to replace the conventional fossil-based economy. With this focus, Volume 2 summarizes up-to-date literature knowledge and discusses the advances in algal cultivation, genetic improvement, wastewater treatment, resource recovery, commercial operation, and technoeconomic analysis of algal biotechnology.

FEATURES

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• Discusses in detail recent developments in algae cultivation and biomass harvesting

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• Provides an overview of genetic engineering and algal-bacteria consortia to improve productivity

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• Presents applications of algae in the area of wastewater treatment and resource recovery

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• Provides case studies and technoeconomic analysis to understand the algal biorefinery

Shashi Kant Bhatia, PhD, is an Associate Professor in the Department of Biological Engineering, Konkuk University, Seoul, South Korea.

Sanjeet Mehariya, PhD, is a Postdoctoral Researcher in the Department of Chemistry, Umeå University, Umeå, Sweden.

Obulisamy Parthiba Karthikeyan, PhD, is a Research Scientist and Lecturer (Adjunct) in the Department of Civil and Environmental Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota, USA.

1 Genetic Engineering in Improving the Output of Algal Biorefinery

Yogita Sharma, Gajendra Pal Singh, and Chandra Pal Singh

Algal Biotechnology Lab, Department of Botany, University of Rajasthan, Jaipur, Rajasthan, India

Ameesh Dev Singh

B.B.D. Government College, Chimanpura, (Shahpura), Jaipur, Rajasthan, India

Sanjeet Mehariya

Department of Chemistry, Umeå University, Umeå, Sweden

Obulisamy Parthiba Karthikeyan

College of Technology, University of Houston, Houston, Texas, USA

Antonio Molino

Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Department of Sustainability, Naples, Italy

DOI: 10.1201/9781003188094-1

CONTENTS

1. 1.1 Introduction
2. 1.2 General Aspects of Algal Genetic Engineering
3. 1.2.1 Omics of Algal Transformation
4. 1.2.2 Algal Genome for Genetic Manipulation
5. 1.2.2.1 Nucleus
6. 1.2.2.2 Chloroplast
7. 1.2.2.3 Mitochondrion
8. 1.2.3 Limitations to Algal Genetic Engineering
9. 1.3 Methods of Genetic Engineering in Algae
10. 1.3.1 Glass Bead Agitation
11. 1.3.2 Electroporation
12. 1.3.3 Microparticle Bombardment
13. 1.3.4 Biological Methods of Transformation
14. 1.3.4.1 Natural Transformation
15. 1.3.4.2 Bacterial Conjugation
16. 1.3.4.3 Agrobacterium tumefaciens–Mediated Transformation
17. 1.3.5 Molecular Tools of Transformation
18. 1.3.5.1 RNA interference (RNAi) and Transposons
19. 1.3.5.2 ZNFs and TALENs
20. 1.3.5.3 CRISPR/Cas9
21. 1.4 Trends in Genetic Engineering of Algal Bioproducts
22. 1.4.1 Biofuel and Energy Biosynthesis
23. 1.4.2 Lipid Biosynthesis
24. 1.4.3 Pigment Biosynthesis
25. 1.4.4 Biopharmaceuticals Synthesis
26. 1.4.5 Other Biocompounds Obtained from Genetically Manipulated Algae
27. 1.5 Conclusion and Future Prospects
28. References

1.1 Introduction

As the world population rises continuously, the demand for food and energy sources has increased coherently. To meet these demands, it has become essential to look out for more sustainable sources. In the wake of identifying different renewable sources for food, feed, and fuel, algae have emerged as a potential platform and storehouse of a plethora of different bioactive compounds (Chia et al., 2018). Earlier, microalgal species were targeted for biofuel production. But recent advancements in biochemical and genetic engineering have made them a bioprospecting platform for manufacturing pigments, lipids, biopharmaceutical, cosmeceutical, nutraceutical products for human consumption, and fortified feed for cattle as well as aquaculture. Microalgae function as microscopic biorefineries which can fix atmospheric CO₂ via photosynthesis into a variety of high-value bioactive compounds and unlike higher plants they do not contend for land and water resources. Vitamins, pigments, and other secondary metabolites are usually synthesized by algae under stress conditions to protect their vital organelles and biosynthetic pathways against photo-oxidative damage, ROS accumulation, and osmoregulatory losses. Naturally produced compounds have higher marketability and are preferred over the ones produced synthetically. Bacteria and fungi have been long used as biomanufacturing platforms for antibiotics, enzymes, vaccines, and foreign protein production, but the successful genetic manipulations in algal genomes whether nuclear, chloroplastic, or mitochondrial can increase the profitability by synthesizing multiple products from single algal systems. These studies have expanded the arenas for current algal research towards more specific and targeted molecular studies to enhance the productivity of desired algae-based compound(s). The development of high reproducible strains, more specialized molecular toolkits for DNA delivery and successful genomic integration have increased algal output. Rapid advancements in genome editing technology have escalated their productivity at industrial levels for mass production.

The concept of biorefinery emerged in 1977 (then called as “green biorefinery”) (Schieb et al., 2015), which runs on the general principles of a conventional oil- refinery where crude oil is converted to specific petro-chemical products (Smith and Consultancy, 2007) while the former involves the conversion of naturally available biomass to marketable bioproducts and energy sources. Therefore, biorefineries integrate the processes and technologies of biomass conversion (Bridgwater, 2013) which involve thermochemical, biochemical, or simply chemical (Hossain, 2019) methods for separation, filtration, and extraction of bioactive compounds (Huang and Ramaswamy, 2013). Currently, several biorefineries are running at a large scale throughout the world and their principles lie upon the type of biomass they consume and the desired product which has to be extracted. However, the major concerns with their commercialization are the technical constrictions that arise during their harvest, the amount of energy and production cost involved in the downstream processing pathways, lack of co-production methods, and recyclability of solvents while the yields are very marginal (0.3 to 5kg/m³) (Li et al., 2008; Gouveia and Gouveia 2011; Gerardo et al., 2015; Grima et al., 2013). Thus, a combined and holistic approach that involves optimal energy and cost requirements with maximum yield efficiency and co-production of different bioactive compounds with minimum waste generation is necessary to utilize the full potential of these microscopic biofactories. For this, several bioengineering processes are being tailored with a focus to develop step-specific techniques for increasing biomass production per unit volume, designing bioreactors, biochemical and genetic transformation equipped with novel biorefinery approaches for yield optimization (Francavilla et al., 2015). Figure 1.1 represents a general outline of how algal biotechnology and genetic engineering aim at improving the biorefinery output of different algal strains.

Figure 1.1 A general outline of algal biotechnology for bioprospecting high-value algae-based compounds.

In this chapter, the authors have discussed different facets of algal genetic engineering. The eukaryotic algae and cyanobacteria are a house to several high-value compounds which are a result of an integrated network of biosynthetic pathways regulated by nuclear as well as organelle genomes. The key to a successful genetic transformation lies in the designing of the plasmid vector, DNA delivery tools selected, followed by stable genomic integration and expression. Hence, the popular delivery tools used in various algal models have been exemplified in this chapter. The current trends in algal genome editing by employing cutting-edge tools and technologies for obtaining marketable bioactive compounds have also been highlighted in later sections. Lastly, this chapter addresses the ongoin...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• Preface
• Acknowledgments
• Editors
• Contributors
• Chapter 1 Genetic Engineering in Improving the Output of Algal Biorefinery
• Chapter 2 Recent Development in Microalgal Cultivation and Biomass Harvesting Methods
• Chapter 3 Application of Microalgae for CO2 Mitigation and Sequestration of Flue Gas
• Chapter 4 Microalgae-Based Nutrient Recovery from Urban Wastewater
• Chapter 5 Microalgal Metal Remediation from Industrial Wastewater
• Chapter 6 Application of Microalgae for Removal of Pharmaceuticals from Aqueous Matrices
• Chapter 7 C1-Proteins Prospect for Production of Industrial Proteins and Protein-Based Materials from Methane
• Chapter 8 Microalgal Consortia and Their Biotechnological Applications
• Chapter 9 Algae from Extremophilic Conditions and Their Potential Applications
• Chapter 10 LCA: A Tool to Develop Sustainable Microalgal Biorefineries
• Chapter 11 Commercial Operation of Algal Technology: A Case Study and Techno-economic Analysis
• Index