Bioremediation of Pollutants

From Genetic Engineering to Genome Engineering

Vijai Singh, Vimal Chandra Pandey

• Publisher: Elsevier
• Year: 2020
• Print ISBN: 9780128190258
• eBook ISBN: 9780128190265
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

Bioremediation of Pollutants: From Genetic Engineering to Genome Engineering provides insights into genetic and genome engineering strategies in bioremediation, covering a wide range of microorganisms that are key to the removal of pollutants. The book includes discussions on root engineering, transgenic plants, metagenomics, bioreactors, molecular biology tools, genome editing, synthetic biology, microbial indicators, biosurfactants, biofilms, genetically modified organisms, and engineered fungi and bacteria. Presented by top experts in the field, this resource captures the essence and diversity of bioremediation methodologies in a single source.Students and beginners in environmental science, researchers, soil scientists, genetic and genome engineers, stakeholders and policymakers interested in improving this rapidly growing area of research will find this resource extremely useful.- Draws together research from eminent scientists from across the globe in the areas of phytoremediation and microbial remediation- Includes case studies of engineered bacterial remediation- Covers the genome editing CRISPR-Cas9 system that has been less explored in plants and microorganisms

Part I

Phytoremediation

Outline

• 1 Phytoremediation—a holistic approach for remediation of heavy metals and metalloids
• 2 Role of potential native weeds and grasses for phytoremediation of endocrine-disrupting pollutants discharged from pulp paper industry waste
• 3 Transgenic plants in phytoremediation of organic pollutants
• 4 Progress, prospects, and challenges of genetic engineering in phytoremediation
• 5 Recent advances in phytoremediation using genome engineering CRISPR–Cas9 technology

1

Phytoremediation—a holistic approach for remediation of heavy metals and metalloids

Sumya Pathak^{1, 2}, Aditya Vikram Agarwal^{1, 2} and Vimal Chandra Pandey³*, ¹Department of Biochemistry, University of Lucknow, Lucknow, India, ²DST—Center for Policy Research, Babasaheb Bhimrao Ambedkar University, Lucknow, India, ³Department of Environmental Science, Babasaheb Bhimrao Ambedkar University, Lucknow, India*, Corresponding author

Abstract

Anthropogenic mobilization of heavy metals (HMs) and metalloids in the air, water, and soil is a grave threat to human health and the environment. HM and metalloid pollution in soil has emerged as a major concern worldwide due to its far reaching implications of contaminating the food chain. Therefore, there is an urgent need for an effective, economical, sustainable, and environmental-friendly approach to remediate HM and metalloid contaminated soils. Phytoremediation is a plant-based remediation technology, which offers a promising alternative approach to HM and metalloid pollution. This technology utilizes various natural mechanisms including phytoextraction, phytostabilization, phytovolatilization, and phytodegradation to degrade or accumulate metal(loid)s taken up from soil. Phytoremediation is a relatively recent technology as compared to other conventional remediation solutions; however it has gained much popularity due to its convenient and ethnic nature. In this chapter we focus on understanding the biological and physicochemical processes for different phytoremediation mechanisms along with a detailed discussion about factors governing the affectivity of these mechanisms. This chapter also gives insight into various advantages and disadvantages for improving sustainability and economic robustness of different approaches in varied conditions of soil contamination.

Keywords

Metal(loid)s; hyperaccumulators; phytoextraction; phytoremediation mechanism; rhizosphere

1.1 Introduction

During the last century, rapid urbanization and industrialization have acutely disturbed our environmental matrices globally. Unregulated disposal of pollutants, generated via various anthropogenic activities like mining, smelting, burning of fossil fuels, use of fertilizers, military operations, and sewage have casted an irreversible negative effect on all forms of life on Earth including humans (Cristaldi et al., 2017). These environmental pollutants in the form of solid, liquid, and gaseous wastes enter the food chain through various routes of exposure and have become the major cause of increasing health issues across the globe (Muthusaravanan et al., 2018). Uncontrolled production and accumulation of environmental pollutants have critically hampered the soil health too, through soil degradation processes including erosion, salinization, and heavy-metal contamination (da Conceição Gomes et al., 2016).

Elements of the periodic table are classified as heavy metals (HMs) if their density is more than 5 g/cm³. The majority of the transition elements, including copper, lead, zinc, mercury, arsenic, and cadmium, belong to HMs (Laghlimi et al., 2015). HMs naturally exist in the Earth’s crust and are an intrinsic part of soil in many parts of the world with their profile (qualitative and quantitative measures) varying from one place to another. Some HMs (copper, manganese, zinc, etc.) have biological importance acting as micronutrients for most organisms, however, others (cadmium, lead, mercury, and arsenic) are toxic in nature with no known biological relevance (Luo et al., 2016).

The geogenic existence of HMs has never been reported to pose concern for the environment or human health. However, man-made (anthropogenic) activities like the use of agro-chemicals, over-exploitation of underground water, and waste from utensil industries have directed toward magnification of HM accumulation in soil, resulting in deleterious consequences (Clemens, 2006). It has been reported that over recent decades the global discharge of HMs into the environment has reached 22,000 metric ton for cadmium, 939,000 metric ton for copper, 783,000 metric ton for lead, and 1,350,000 metric ton for zinc (de Mello-Farias et al., 2011). This magnitude of enormous discharge results in accumulation of HMs in the agricultural soils and water resources, which eventually pose a threat to human health, due to potential risk of their entry into the food chain (Sarwar et al., 2017). HM contamination of soil has now turned out to be a worldwide menace not just because of unchecked production of metallic waste but also due to its immutable characteristics, persistence, and biomagnifications.

It has been recently brought forth that approximately 10 million people around the world suffer from health issues due to HM pollution in soil (Shakoor et al., 2013). China stands among the worst hit countries with HM contamination of soil. Studies report that more than 15% farmland and agricultural land area in the country have become unusable due to accumulation of HM contamination, exceeding far beyond the limit of environmental quality standards of soil. It has been found out that cadmium tops the chart of metallic contaminants (7%) in soil samples across China. Next to China, soil contamination has become an alarming issue to the European Union with 3.5 million potentially contaminated and 0.5 million highly contaminated sites seeking immediate remediation measures. Several European countries including Germany, Italy, Spain, Denmark, France, Slovakia, and many more have all been affected by soil contamination. In 2012 it was identified that approximately 600,000 ha of brown field sites in America are contaminated with HMs, giving this kind of pollution a cosmopolitan status (Mahar et al., 2016).

Restoration of sites contaminated with these hazardous and persistent pollutants requires cost effective and environmental-friendly ways of remediation. In the last two decades immense efforts have been made toward development of a range of soil-cleaning approaches which are based on physical, chemical, ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• List of contributors
• About the editors
• Foreword
• Preface
• Acknowledgments
• Part I: Phytoremediation
• Part II: Microbial Remediation
• Index