Preface

The book series "Microbes and Microbiomes for a Clean and Green Environment" explores the current state of polluted and degraded ecosystems, emphasizing the vital roles that microbes and microbiomes play in managing natural resources and restoring ecosystems. It also highlights the significance of these microorganisms in generating renewable energy, reducing greenhouse gas emissions, mitigating climate change impacts, sustaining marine, mangroves, and wetlands ecosystems, promoting sustainable industrial practices, and contributing to socio-economic development and the security of human and animal health.

We are entering a unique era characterized by various environmental challenges contributing to adverse effects on the ecosystem of the planet and impacting human health and quality of life. At the start of the twenty-first century, a significant concern within the ecological context is the degradation of ecosystems and environmental imbalances, primarily caused by increasing human activities. To tackle this pressing issue, restoration ecology has emerged, which focuses on the potential of microbes and microbiomes as key solutions for creating a clean and green environment. The practical applications of this science offer cost-effective and viable options.

One of the primary objectives of the UN Convention on Biological Diversity from 2011 to 2020 was to restore at least 15% of the world's damaged ecosystems. In 2011, world leaders launched the "Bonn Challenge," committing to rehabilitating 150 million hectares of deforested and degraded land. Furthermore, in 2015, the UN formalized these global commitments by endorsing the 2030 Sustainable Development Goals, which emphasizes ecological restoration's importance.

Microorganisms are remarkably diverse and essential for sustaining ecosystems on a global scale. They provide critical services that enhance productivity and maintain a stable environment for human life.

Volume 2, "Microbes as Agents of Change for Sustainable Development, " explores the pivotal role of microbes and microbiomes in restoring degraded ecosystems and advancing sustainable practices.

In Chapter 1, Sinduja et al., emphasize the essential role of microorganisms in sustaining Earth's biogeochemical cycles. They explore the complexity of microbial communities and their contributions to ecosystem processes. Additionally, the chapter discusses strategies for effectively managing natural resources and highlights the impact of beneficial soil microbes on nutrient cycling.

Bioleaching is increasingly used for metal extraction and effective bioremediation of polluted sites. This technique is cost-effective and environmentally friendly, helping to restore damaged ecosystems to their original state. In Chapter 2, Poornima et al., provide a comprehensive overview of bioleaching, covering its various types, the microbes involved, the pathways of bioleaching, and the role of these microbes in the bioremediation of polluted habitats.

In Chapter 3, Sajish et al., discuss the fundamental principles of microbial fuel cells (MFCs), types of bioreactors, factors that influence the development of MFCs' performance, and the crucial role microbes play in catalyzing these systems. They also explore various approaches to enhancing the overall efficiency of MFCs for practical applications, including genetic engineering, biofilm engineering, and electrode engineering.

Recent concerns about energy crises, rising pollution, and unpredictable climate change have made bioenergy an essential alternative to fossil fuels. In this context, Chapter 4, authored by Oyelade et al., comprehensively reviews how sustainable bioenergy production through microbes utilizing various biomass feedstocks generates clean and green energy and how, ultimately, it can help mitigate environmental issues, restore ecosystems, and achieve energy security.

Microbes play a significant role as either generators or consumers of greenhouse gases such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) through various processes. Sethupathi et al., in Chapter 5, discuss the role of microbes and the microbiome in the emission of significant greenhouse gases like CO2, CH4, N2O, and NH3. This chapter also discusses the potential of the microbiome in mitigating these greenhouse gases.

Climate change is now a reality, largely due to the release of carbon dioxide from soil into the atmosphere. In Chapter 6, Al-Jawhari et al., examine the balance of soil CO2, the environmental impacts of climate change, and the significance of the soil carbon cycle, especially the roles played by microbial decomposers. The chapter also addresses the interconnections between the carbon cycle in the soil, the ocean, and ecosystem restoration within the context of climate change.

Microorganisms are pervasive and comprise the "unseen majority" of marine environments. Although marine isolates have been the subject of laboratory-based culture methods for more than ten years, we still don't completely understand their ecology. Thus, in Chapter 7, Poornachandhra et al., explore marine microbial diversity, its utilization in bioremediation, and its role in ecosystem sustainability.

Mangroves and wetlands are essential ecosystems that offer numerous ecological and economic benefits. Unfortunately, human activities have led to the rapid degradation of these crucial areas. In Chapter 8, Haghani et al., analyze the key characteristics of the microbial communities that inhabit mangroves and wetlands. They describe the biochemical transformations performed by these microorganisms and highlight the complexity of their interactions within these ecosystems.

In Chapter 9, Jerome et al., highlight the importance of forest microbiomes in ecosystem restoration and sustainability. Forest microorganisms are crucial in how plants interact with their soil environment and are vital for accessing essential soil nutrients. This chapter examines the above-ground and below-ground ecosystems of a forest microbiome, emphasizing the significance of soil microorganisms and their diverse relationships, including parasitism, mutualism, and commensalism.

The sustainable industrial revolution is the way forward to help humankind prolong its existence on Earth. In Chapter 10, John et al., enlighten us on the role of the microbiome in a sustainable industrial production system. They discussed the energy sector's current status, microbes' role in organic and amino acid production, and microalgae's role in sustainable agriculture.

The microbiome plays a vital role in human development, immunity, and nutrition, where beneficial bacteria establish themselves as colonizers rather than destructive invaders. In chapter 11, Pradyutha et al., introduce microbes' role in human and animal health security.

This chapter also discusses various human and animal diseases and the potential of microbiota, such as probiotics, in disease treatment.

We sincerely thank all the authors for their outstanding contributions. Our gratitude also extends to the entire team at Bentham Science Publishers, especially Mrs. Fariya Zulfiqar (Manager Publications), for her exceptional management of this book throughout all stages of publication. We are confident that this volume in the book series will be widely appreciated by researchers and professionals alike.