Microbes for Sustainable Development and Bioremediation

Ram Chandra, RC Sobti

• Publisher: CRC Press
• Year: 2019
• Print ISBN: 9780367226008
• eBook ISBN: 9781000733358
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biotechnology
• Index: Biological Sciences

Microbes are the predominant form of life on the planet due to their broad range of adaptation and versatile nutritional behavior. The ability of some microbes to inhabit hostile environment incompatible with most forms of life means that their habitat defines the extent of the biosphere and delineates the barrier between the biosphere and geosphere. The direct and indirect role of microbes that include bacteria, fungi, actinomycetes, viruses, mycoplasma, and protozoans are very much important in development of modern human society for food, drugs, textiles, agriculture, and environment. Furthermore, microorganisms and their enzyme system are responsible for the degradation of various organic matters.

Microbes for Sustainable Development and Bioremediation emphasizes the role of microbes for sustainable development of ecosystem. Environmental microbiology role in biogeochemical cycle and bioremediation of environmental waste is major theme, which comprises the following aspects:

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• Bacterial phytoextraction mechanism of heavy metals by native hyperaccumulator plants from complex waste-contaminated site for eco-restoration

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• Role of microbial enzyme for eco-friendly recycling of industrial waste

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• Field-scale remediation of crude oil–contaminated desert soil and treatment technology

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• Microbial technology for metal recovery from e-waste printed circuit board

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• Impact of genomic data on sustainability of ecosystem

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• Methane monooxygenases: their regulations and applications

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• Role of microbes in environmental sustainability and food preservation

This book will be directly beneficial to researchers and classroom students, in areas of biotechnology, environmental microbiology, molecular biology, and environmental engineering with specialized collection of cutting-edge knowledge.

1 Bacterial-Assisted Phytoextraction Mechanism of Heavy Metals by Native Hyperaccumulator Plants from Distillery Waste–Contaminated Site for Eco-restoration

Vineet Kumar and Ram Chandra

Babasaheb Bhimrao Ambedkar University

CONTENTS

1.1 Introduction

1.2 Plant-associated Bacteria

1.2.1 Plant Growth–Promoting Rhizobacteria

1.2.1.1 Direct Plant Growth Promotion by Rhizobacteria

1.2.1.2 Indirect Plant Growth Promotion by Rhizobacteria

1.3 Microbial Ecology of the Rhizosphere

1.3.1 Bacteria

1.3.2 Fungi

1.3.3 Archaea

1.3.4 Protozoa

1.3.5 Human Pathogens

1.4 Categories of a Plant Grown on Heavy Metal–Contaminated Sites

1.4.1 Metal Excluders

1.4.2 Metal Indicators

1.4.3 Metal Accumulators

1.5 Hyperaccumulator Plants and Their Characteristics

1.6 Phytoextraction of Heavy Metals by Potential Native Plants from Distillery Waste and Other Complex Organometallic Waste

1.7 Heavy Metal Accumulation and Detoxification Mechanism of the Plant during In Situ Phytoremediation of Distillery Waste

1.7.1 Metal Phytoavailability in the Rhizosphere

1.7.2 Transport of Heavy Metals across Plasma Membranes of Root Cells

1.7.3 Root-to-Shoot Translocation of Heavy Metals

1.7.4 Detoxification and Sequestration of Heavy Metals in Aerial Parts of Plants

1.8 Use of Transgenic Plants for Heavy Metal Accumulation

1.9 Conclusion

1.10 Recommendation and Future Prospects

References

1.1 Introduction

Heavy metals (HMs) forms the main group of inorganic contaminants, and the restoration of sites contaminated such compounds is one of the major challenges for environmentalist (Deng et al. 2004; Tchounwou et al. 2012). Phytoextraction, also called phytoaccumulation, phytoabsorption, or phytosequestration, is one of the most promising and developing phytoremediation technologies applied for the removal of toxic HMs from complex environments (Garbisu and Alkorta 2001; Chandra et al. 2015; Chandra and Kumar 2018). It is an emerging, esthetically pleasing, ecologically nonintrusive, socially accepted, in situ plant-based technology that is being applied for cleanup of toxic metals and cocontaminated (a mixture of inorganic and organic pollutants) and/or polluted sites globally or renders them harmless (Chaney et al. 1997; Chandra and Kumar 2017a; Chandra et al. 2018a). Under normal growing conditions, plants can potentially accumulate certain HMs ions an order of magnitude greater than the surrounding medium (Cunningham et al. 1995; Bhargava et al. 2012). Generally, there are two strategies of phytoextraction: (i) chelate-assisted or induced phytoextraction and (ii) continuous phytoextraction. The chelate-assisted phytoextraction is based on the fact that the application of metal chelators to the soil significantly enhances metal accumulation by plants (Wu et al. 1999; Evangelou et al. 2007), whereas continuous phytoextraction depends on the natural ability of some plants to accumulate, translocate, and resist high amounts of HMs over the complete growth cycle (Garbisu and Alkorta 2001). At the contaminated site, there are many plants that have several strategies to avoid HMs uptake or tolerate the presence of excess HMs in soil, sludge, and/or sediment (Chandra and Kumar 2017a; Chandra et al. 2018c,d). Based upon this, there are three categories of plant i.e. metal excluders, metal indicators, and hyperaccumulators (Baker 1981; Baker and Brooks 1989). Among them, hyperaccumulator plants are the best candidate for metal remediation purpose from the contaminated site, as they can increase internal sequestration, translocation, and accumulation of metals in their harvestable biomass(stem or leaves) (Baker and Brooks 1989; Leitenmaier and Küpper 2013; Chandra et al. 2018b,c). Usually, hyperaccumulators have high accumulation capacity, i.e., the minimum concentration in the shoots of a hyperaccumulator for arsenic (As), lead (Pb), copper (Cu), nickel (Ni), and cobalt (Co) should be greater than 1,000 mg/kg dry mass, and zinc (Zn) and manganese (Mn) should be 10,000 mg/kg, gold (Au) is 1 mg/kg, and Cd is 100 mg/kg, respectively (Baker 1981). The idea of using hyperaccumulator plants to extract and remove metals from contaminated site was first introduced and developed by Chaney (1983). However, the efficiency of metal acquisition and accumulation in plant tissues differed considerably between the elements, plant species, and plant tissues. Four processes are generally believed to be crucial for heavy metal accumulation in plant tissues: uptake of metals by roots, transport of metals from roots to shoot, complexation with chelating molecules, and compartmentalization into the vacuole (McGrath and Zhao 2003; Chandra and Kumar 2018). Although plants suitable for phytoremediation have to be adapted to the polluted environment, the presence of organic pollutants in soil generally reduces plant development and eventually phytoremediation efficacy. As elevated levels of metals are toxic to most plant species apart from hyperaccumulators, leading to impaired metabolism and reduced plant growth, the potential for phytoextraction of HMs is highly restricted and necessitates the development of other phytoremediation strategies for HMs contaminated soils.

The rhizoplane (the part of root remaining in contact with soil, sludge, or water) of growing plant is the most active zone of the presence of various microbial communities. However, the interface between microbes and rhizosphere is considered to greatly influence the growth and survival of plants at contaminated sites (Abou-Shanab et al. 2007, 2008; Kumar and Chandra 2018). The rhizosphere microbial communities includes bacteria, fungi, nematodes, protozoa, algae, and microarthropods (Figure 1.1). Among them, bacteria are the most abundant microorganisms in the rhizosphere, occupying 1 g of soil with up to half a billion individual cells. At contaminated sites, plants and bacteria coevolved to interact with each other in complex manners, which yielded a vast spectrum of interfaces between the two kingdoms of life. The discovery of rhizosphere bacteria that are heavy metal resistant and able to promote plant growth has raised high hopes for ecologically friendly and cost-effective strategies toward eco-restoration of HMs–polluted sites (Abou-Shanab et al. 2008; Ahemad and Khan 2010a,b; Ahemad 2014a,b). Therefore, alternative phytoremediation methods that exploit rhizosphere bacteria to reduce metal toxicity to plants have been investigated (Abou-Shanab et al. 2007). Rhizobacteria colonize the close vicinity of roots, whereas endophytic bacteria colonize the plant interior without causing pathogenicity to their host plant. Rhizobacteria have been investigated for their plant growth–promoting capacity, and in the last decade, the use of such bacteria to enhance phytoremediation efficiency has been reported (Glick 2003, 2012). When using plants and microbes in combination, the plant provides the habitat as well as nutrients to the associated rhizospheric and endophytic bacterial communities. In return, the bacteria enhance the stress tolerance of the plant or improve plant growth and detoxify the plant environment by degrading the pollutant (Glick 2010, 2014). There are complex and varied interactions between plants and their associated microbes, and these interactions have been extensively studied and used to increase soil fertility, plant development, and phytoremediation of polluted soil and water. Muehe et al. (2015) compared the effects of a “native” and a strongly disturbed (gamma-irradiated) soil microbial communities on Cd and Zn accumulation by the Arabidopsis halleri plant in soil microcosm experiments. A. halleri accumulated 100% more Cd and 15% more Zn when grown on the untreated than on the gamma-irradiated soil. Pyrosequencing of 16S rRNA gene amplicons of DNA extracted from rhizosphere samples of A. halleri showed the higher relative sequence abundance of microbial taxa Lysobacter, Streptomyces, Agromyces, Nitrospira, Candidatus, and Chloracido bacterium in the rhizospheres of A. halleri plants grown on untreated than on gamma-irradiated soil, leading to hypotheses on their potential effect on plant metal uptake. Kumar et al. (2018) used high-throughput sequencing to explore the rhizosphere microbial diversity in the alfalfa and barley-planted oil-contaminated soil samples. The analysis of 16s rRNA sequences showed Proteobacteria to be the most enriched (45.9%) followed by Bacteriodetes (21.4%) and Actinobacteria (10.4%) phyla. The oil-contaminated rhizospheric soil showed enrichment of known oil-degrading genera, such as Alcanivorax and Aequorivita, later being specifically enriched in the contaminated soil samples planted with barley. Authors were found a few well-known oil-degrading bacterial groups to be enriched in the oil-contaminated planted soil samples compared with the untreated samples.

FIGURE 1.1 (a) Overview of microorganisms present in the rhizosphere. The circle’s size, except for viruses, is a measure of the average number of genes in the genomes of representative species of each group of organisms; the size (or size range) of their respective genomes is indicated between parentheses. (Reprinted from Mendes et al. 2013 with Permission from Oxford University Press.) (b) Phylum level distribution of microbial population across samples. Phyla represented by at least 0.5% of the total assigned sequences (11 of total 36 phyla) are shown here. CS, clean sandy soil; BC, control oil-contaminated bulk soil without barley plants; BO, barley-planted oil-contaminated rhizosphere soil; AC, control oil-contaminated bulk soil without alfalfa plants; AO, alfalfa-planted oil-contaminated rhizosphere soil. (Reprinted with Permission from Kumar et al. 2018).

Distillery industry occupies a place of prominence in the Indian economy, but it contributes significantly toward the contamination of environment (Kumar and Chandra 2020; Chandra et al. 2018c,d). It is one of the highly polluting industries due to discharge of the huge amount of sludge as by-product during anaerobic digestion of spent wash (Chandra and Kumar 2017a,b; Kumar and Chandra 2019). The sludge is considered as a source of toxic HMs and various androgenic-mutagenic compounds, and its disposal in environment is problematic. In addition, distillery sludge also consists of a mixture of several recalcitrant organic compounds along with melanoidins (Chandra and Kumar 2017a,b). Distillery sludge is the most common habitat that harbors unique types of bacterial species, which are capable of running widespread in situ bioremediation activities (Chandra and Kumar 2017b). The growing autochthonous bacterial species act at the primary level to loosen the interaction of organometallic bond through their enzymatic action, which makes metal availability to plant. Generally, plants use varied mechanisms to uptake different organic and inorganic pollutants, which make the basis of phytoremediation technology (Cunningham et al. 1997; Alkorta et al. 2004). They employ numerous kinetic processes, including phytostabilization, phytovolatilization, and phytodegradation, for removal of organic compounds, whereas for inorganics, phytostabilization, phytoextraction, and phytovolatilization are involved (Figure 1.2a; Cunningham et al. 1997, 1995; Salt et al. 1998; Chandra and Kumar 2018).

FIGURE 1.2 Phytoramediation strategies and heavy metals accumulation and detoxification in plant. (a) Illustration of various strategies of plant for phytoremediation of heavy metals and organic pollutants at contaminated sites. Plants-associated bacteria influence heavy metal accumulation in plant tissues and promote plant growth at heavy metals–contaminated site. (Modified from Chandra and Kumar 2018.) (b) Schematic mechanism of heavy metal transportation, detoxification, and accumulation in plant tissues. (Modified from Verbruggen et al. 2009.)

1. Phytoextraction involves the use of pollutant-accumulating plants to remove HMs or organics from the soil, sludge, sediment, or water by concentrating them in harvestable parts of the plant. At the end of the growth period, plant biomass is harvested, dried, or incinerated, and the contaminant-enriched material is deposited in a special dump or added into a smelter. The energy gained from burning of the biomass could support the profitability of the technology, if the resultant fumes can be cleaned appropriately.
2. In phytodegradation, contaminants are taken up from soil or water, metabolized in plant tissues, and broken up to less toxic or nontoxic compounds within the plant by several metabolic processes via the action of compounds produced by the plant. Besides, the contaminants are also degraded in the rhizopshere by the proteins or enzymes pro...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Editors
• List of Contributors
• Chapter 1 Bacterial-Assisted Phytoextraction Mechanism of Heavy Metals by Native Hyperaccumulator Plants from Distillery Waste–Contaminated Site for Eco-restoration
• Chapter 2 Microbial Enzymes for Eco-friendly Recycling of Waste Paper by Deinking
• Chapter 3 Advances in Industrial Wastewater Treatment
• Chapter 4 Microbial Degradation of Pesticides in the Environment
• Chapter 5 Dissimilatory Iron-Reducing Bacteria: A Template for Iron Mineralization and Nanomaterial Synthesis
• Chapter 6 Heat and Chemical Pretreatment of Bacterial Cells to Enhance Metal Removal
• Chapter 7 Field-Scale Remediation of Crude Oil–Contaminated Desert Soil Using Various Treatment Technologies: A Large Remediation Project Case Study
• Chapter 8 Microbial Processes for Treatment of e-Waste Printed Circuit Boards and Their Mechanisms for Metal(s) Solubilization
• Chapter 9 Application of Thermostable Enzymes for Retaining Sustainable Environment: Improvement of the Enzymatic Activities of Two Thermophilic Archaeal Enzymes without Decreasing Their Stability
• Chapter 10 Metagenomics: A Genomic Tool for Monitoring Microbial Communities during Bioremediation of Environmental Pollutants
• Chapter 11 Microbial Capacities for Utilization of Nitroaromatics
• Chapter 12 Methane Monooxygenases: Their Regulations and Applications in Biofuel Production
• Chapter 13 Plant Growth–Promoting Rhizobacteria (PGPR) and Bioremediation of Industrial Waste
• Chapter 14 Fungi Treatment of Synthetic Dyes by Using Agro-industrial Waste
• Chapter 15 Beneficial Microbes for Sustainable Agriculture
• Chapter 16 Detoxification of Biomedical Waste
• Chapter 17 Immobilized Enzyme-Based Biocatalytic Cues: An Effective Approach to Tackle Industrial Effluent Waste
• Chapter 18 Lipase of Lactic Acid Bacteria: Diversity and Application
• Chapter 19 Role of Microbes in Environmental Sustainability and Food Preservation
• Chapter 20 Bioinformatics and Applications in Biotechnology
• Chapter 21 Microbial Bioinoculants for Sustainable Agriculture: Trends, Constraints, and Future Perspectives
• Index