Marine Microbial Bioremediation

Anjana K Vala, Dushyant R Dudhagara, Bharti P Dave, Anjana Kiritsinh Vala, Dushyant R. Dudhagara, Bharti Dave, Anjana K Vala, Dushyant R Dudhagara, Bharti P Dave, Anjana Kiritsinh Vala, Dushyant R. Dudhagara, Bharti Dave

• Publisher: CRC Press
• Year: 2021
• Print ISBN: 9780367770037
• eBook ISBN: 9781000382600
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

Increased industrialization and urbanization has polluted the marine environment, the largest ecosystem. Hence, sincere efforts must be made to decontaminate marine ecosystem for sustainable use of oceans and their bioresources. Microbial population in the marine environment plays a very crucial role in degrading, transforming and detoxifying the pollutants. This book presents contributions from leading scientists across the globe who have worked extensively on polluted marine ecosystem in removal of pollutants, mycoremediation of salinity ingressed soils, etc. This book will be useful to the scientific community, stake holders and policy makers involved in research related to environmental microbiology and marine microbiology in particular. The book will also be of benefit to the student community interested in marine microbial bioremediation.

1

Degradation of Polycyclic Aromatic Hydrocarbons By Halophilic Aquatic Fungi

Elisabet Aranda¹, Gabriela Ángeles de Paz¹, María del Rayo Sánchez² and Ramón Alberto Batista-García^3,*

Institute of Water Research, University of Granada. Ramón y Cajal, 4, Bldg. Fray Luis, 18071 Granada. Spain.

Centro de Investigación en Biotecnología. Universidad Autónoma del Estado de Morelos. Cuernavaca, Morelos. Mexico.

Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas. Universidad Autónoma del Estado de Morelos. Cuernavaca, Morelos. Mexico.

Corresponding author: [email protected]

INTRODUCTION: PAHS IN THE ENVIRONMENT

Polycyclic aromatic hydrocarbons (PAHs), also called polynuclear aromatic hydrocarbons or polyarenes, represent a well-known group of toxic chemicals widely distributed in the environment. They are formed by the fusion of two or more rings in linear, angular or clustered configuration. According to the number of fused benzene rings, they are classified as small PAHs, when they have less than up to six benzene rings (naphthalene, anthracene, phenanthrene, pyrene) and large PAHs (more than six benzene rings) (dibenzo [a,f]perylene, dibenzo [a,l] pentacene, benzocoronene, etc.). These organic hydrophobic molecules have a low solubility, which increase with the increase in the ring numbers.

The main source of PAHs are petrogenic or petroleum derived, pyrogenic or combustion derived and biogenic or organism derived – formed naturally through biological processes (Wang et al. 2014b) (Figure 1.1). The petrogenic source of PAHs results from geologic seepage, petroleum spills and petroleum refined product. The release of exhausts and vehicle emissions and organic materials such as creosote, coal tar, crankcase oil, and wood burning account for pyrogenic input. This pyrogenic source can be also natural, as it originated from volcanic eruptions and natural forest fires. In each process, the content on different structures will depend on the starting source and the temperature reached. Then, usually petrogenic processes lead to high percentages of small PAHs with three or fewer rings and pyrogenic processes lead to high percentages of high PAHs with four or more rings (Benner et al. 1990). However, most of the sea pollution is due to daily practices such as navigation, which implies the presence of low amounts of hydrocarbons in the seawater.

FIGURE 1.1 Sources of PAHs in the environment.

Distribution of PAHs

The distribution of PAHs depends on several factors, like chemical and physical properties of these molecules. PAHs are present in the atmosphere as vapors or adsorbed into airborne particulate matter and commonly derived from combustion and volatilization. According to the vapor pressure of different PAHs, they will be distributed differently. The atmosphere is the main dispersal source of PAHs (Manoli and Samara 1999).

Atmospheric PAHs are deposited in soils and sediments being bound to soil particles. Attached to them, they become mobiles, and the mobility will depend on the physical properties of the particles and their mobility in soils. Thus, it is not rare to find PAHs at relative high concentrations in remote areas due to their ability to be transported over long distances. Many hypersaline environments, including coastal lagoons, salt and soda lakes, salterns and seawater are polluted with PAHs compounds and some of these environments usually have a huge ecological, economic and scientific value.

Finally, they can be deposited in sediments and water bodies as the results of effluent from industrial outfalls, storm water from highways or urban runoff from storm drains (Sanders et al. 2002). In river sediments, the concentration is generally higher than in the surrounding water body because they tend to be attached into the organic matter. In water, they usually enter via atmospheric fallout. It has been estimated that 10-80% of PAHs present in the world oceans come from atmospheric sources (Moore and Ramamoorthy 2012). However, petroleum spillage, particularly in the surrounding of oil platforms, industrial discharges, atmospheric deposition, and urban run-off has a relevant role in coastal environments (Neff 1979). As a result, PAHs can be found in all the aquatic environments all over the world (Lima et al. 2005).

Toxicity of PAHs

PAHs are included in the list of priority pollutants by different regulation agencies, such as the US Environmental Protection Agency (USEPA), EU legislation concerning PAHs in food and environment, due to the carcinogenic, teratogenic and mutagenic properties (Luch 2009) (Table 1.1). https://ec.europa.eu/jrc/sites/jrcsh/files/Factsheet%20PAH_0.pdf. PAHs are lipophilic compounds, which can be readily absorbed in a variety of tissues. Particularly, PAH can covalently bind to proteins, RNA and DNA, this last covalent union being the most associated with carcinogenicity (Marston et al. 2001). In addition, some studies have reported their ability to interfere with hormone metabolizing enzymes of the thyroid glands, and their adverse effects on reproductive as well as immune system (Oostinngh et al. 2008).

TABLE 1.1 Names and structures of PAHs frequently monitored according to recommendations by the US Environmental Protection Agency (EPA), the EU Scientific Committee for Food (SCF) and the European Union (EU).

List	Common Name	Structure	List	Common Name	Structure
EPA	Naphtalene		EPA, SCF, EU	Benzo [a] anthracene
EPA	Anthracene		EPA, SCF, EU	Benzo [a] pyrene
EPA	Phenantrene		EPA, SCF, EU	Dibenzo [a,h] anthracene
EPA	Acenaphtene		SCF, EU	Benzo [j] fluoranthene
EPA	Acenaphthylene		EPA, SCF, EU	Benzo [k] fluoranthene
EPA	Fluorene		EU + SCF	Dibenzo [a,e] pyrene
EPA	Fluoranthene		EU + SCF	Dibenzo [a,h] pyrene
EPA	Pyrene		EU + SCF	Dibenzo [a,i] pyrene
EPA, SCF, EU	Chrysene		EPA, SCF, EU	Benzo [ghi] perylene

These compounds are resistant to degradation and they tend to be accumulated for long periods in the environment, causing adverse effects at all the tropic levels. In addition, they are susceptible to photochemical oxidation by UV-light and sunlight in the visible exposure, since the specific molecule makes them absorb the light under this wavelength. Several studies have shown the toxic effects of oxygenated PAHs (Arfsten et al. 1996, Lundstedt et al. 2007), concluding that the acute phototoxic effects of PAHs and nitro-, and oxo-substituted should be considered when conducting environmental risk assessments. PAHs also have an important effect on the microbial communities which are usually accompanied by the enrichment of PAH-tolerant bacteria and fungi (Wang et al. 2014a). Recent studies have shown how the presence of PAHs can accelerate the propagation of genes related to tolerance to pharmaceutical compounds (Wang et al. 2017), highlighting the changes that PAHs can exert on microbial communities.

HALOPHILIC FUNGI IN CONTAMINATED SITES: TAXONOMIC GROUPS

Halophilic aquatic-fungi have been shown to have an important role in biotechnological applications. Particularly, some studies have shown the ability of some halophilic aquatic fungi in degradation of PAH, using them as carbon and energy source for its metabolism (Uratani et al. 2014, Bonugli-Santos et al. 2015). These fungus have developed special phenotypic and molecular adaptations against low water activity and extreme conditions, such as the production of meristem-like structures (Zalar et al. 2005) and genes coding for different transport alkali metal ions (Arino et al. 2010, Gostinčar et al. 2011, Zajc et al. 2013).

There are many taxonomic studies which have described several species of halophilic terrestrial fungi with the ability to degrade PAHs (Márquez-Rocha et al. 2000, Di Gregorio et al. 2016, Pozdnyakova et al. 2016, Kadri et al. 2017). On the other hand, aquatic fungi have not been extensively explored nor employed for bioremediation processes (Harms et al. 2011).

Halophily is expressed in several groups of individual orders and groups of fungi ta...

Table of contents

• Cover
• Title Page
• Copyright Page
• Preface
• Contents
• 1. Degradation of Polycyclic Aromatic Hydrocarbons By Halophilic Aquatic Fungi
• 2. Applications of Marine-Derived Fungi: Biocontrol, Cell Wall Degradation and Soil Remediation
• 3. Effect of Stimulating Agents on Improvement of Bioremediation Processes with Special Focus on PAHs
• 4. Phycoremediation–A Potential Approach for Heavy Metal Removal
• 5. Microalgae Immobilization and Use in Bioremediation
• 6. Bioremediation Markers in Marine Environment
• 7. Antarctic Marine Fungi and Their Potential Application in Bioremediation
• 8. Bacterial Bioremediation of Petroleum Hydrocarbon in Ocean
• 9. Heavy Metals: Applications, Hazards and Biosalvage
• 10. Ketamine: Its Abuse and Effect on Aquatic Ecosystem
• Index