**1. Introduction**

#### **1.1. Pesticides**

Pesticides are pure substances or mixtures of chemicals used to control undesired organ‐ isms during production, harvest, and food storage. These compounds can be organic or inorganic molecules classified according to their chemical structure or type of the target organism [1]. They can be introduced into the environment during their manufacturing, application, or subsequent leaching affecting target and nontarget organisms [2]. The term pesticide, used in this chapter, is a synonym of biocide, agrotoxic, and agrochemical, though, there are more specific definitions that include and exclude different chemicals groups [3]. Regardless of the term used, these compounds act by blocking a vital metabolic process of the target organism [4].

The use of different toxic substances against pests and diseases is dated from antiquity. Different natural products such as nicotine, pyrethrum, tobacco plants extracts (*Nicotiana tabacum* L.) [5] and inorganic compounds such as mercury and sulfur were employed in ancient times [6]. The modern use of pesticides is dated from the twentieth century with the intensive use of inorganic substances like sodium aceto arsenite, calcium fluoride, white arsenic, and others [7]. Since the 1930s, the increased agricultural production demanded the formulation and use of substances with best biocide action [7]. Intensive development of the chemical industry occurred with the Industrial Revolution, which led to an increase in the research, and consequently, the production of new pesticides, which was expanded on a global scale after 1940s [8].

The cultivated area increasing and need for higher agricultural productivity stimulated the use of pesticides, mainly in Brazil. In this sense, the use of pesticides in Brazilian agriculture began in the 1970s encouraged by the National Development Plan (in Portuguese, Plano Nacional de Desenvolvimento) [9]. In 2011, the pesticide market in this country was considered the largest in the world, representing 16% of the global market according to the National Health Surveillance Agency (in Portuguese, Agência Nacional de Vigilância Sanitária, ANVISA) [10].

Over the past 50 years, pesticides had been used to increase the food quantity and quality for a growing world population. While worries about their adverse effects in nontarget organisms, including humans, had been also increased [11]. These chemicals, while having a beneficial effect toward agricultural production, are alien to nature and can produce changes and imbalances [12]. Many of them are toxic not only to insects and harmful pests but also to other living beings that are essential to several environmental processes [6]. Different reactions may act in these chemicals affecting their fate and behavior during natural processes [13]. Therefore, pesticides may be one of the most dangerous contaminants to the environment, since they are very toxic, can bioaccumulate, and be part of chemical, physical, and biological processes in nature.

Pesticides used in agriculture remain in the soil at the application site, or are transported to different parts of the environment, such as sediments, plants, surface and ground waters, marine environments and even volatilized into the atmosphere, depending on their physical‐ chemical properties [14-16]. The metabolic fate of the pesticides also depends on the abiotic environmental conditions (temperature, pH, soil moisture), the microbial community, the pesticide characteristics (hydrophilicity, degree of solubility, molecular weight), and the chemical and biological reactions [18]. Once they entered in the soil, pesticides are transferred or degraded by evaporation, leching, infiltration, adsorption, absorption in inorganic matter and biotic and abiotic degradation [17]. The abiotic degradation occurs through physical and chemical transformations in reactions of hydrolysis, oxidation, reduction, photolysis, and rearrangement [18]. However, the enzymatic transformations performed by microorganisms and plants are the major detoxification pathways [11].

Pesticides are used in several products involving herbicides, fungicides, nematicides, insecti‐ cides, fumigants, and substances used as desiccants, defoliants, and growth regulators [19]. Based on the chemical functional groups of the active ingredients, pesticides may be classified as organochlorines, organophosphates, carbamates, and pyrethroids [20]. Organochlorines, which shows high toxicity and persistence because of their resistance to biotic and abiotic degradations, are especially worrisome [21].

#### **1.2. Organochlorine pesticides**

*num* CBMAI 1677 was able to degrade PCP. These results confirmed the efficiency of marine-derived fungi to biodegrade persistent compounds and could enable the

**Keywords:** Organochlorine pesticide, Agrochemicals, Marine Microorganisms, Bio‐

Pesticides are pure substances or mixtures of chemicals used to control undesired organ‐ isms during production, harvest, and food storage. These compounds can be organic or inorganic molecules classified according to their chemical structure or type of the target organism [1]. They can be introduced into the environment during their manufacturing, application, or subsequent leaching affecting target and nontarget organisms [2]. The term pesticide, used in this chapter, is a synonym of biocide, agrotoxic, and agrochemical, though, there are more specific definitions that include and exclude different chemicals groups [3]. Regardless of the term used, these compounds act by blocking a vital metabolic process of

The use of different toxic substances against pests and diseases is dated from antiquity. Different natural products such as nicotine, pyrethrum, tobacco plants extracts (*Nicotiana tabacum* L.) [5] and inorganic compounds such as mercury and sulfur were employed in ancient times [6]. The modern use of pesticides is dated from the twentieth century with the intensive use of inorganic substances like sodium aceto arsenite, calcium fluoride, white arsenic, and others [7]. Since the 1930s, the increased agricultural production demanded the formulation and use of substances with best biocide action [7]. Intensive development of the chemical industry occurred with the Industrial Revolution, which led to an increase in the research, and consequently, the production of new pesticides, which was expanded on a global scale after

The cultivated area increasing and need for higher agricultural productivity stimulated the use of pesticides, mainly in Brazil. In this sense, the use of pesticides in Brazilian agriculture began in the 1970s encouraged by the National Development Plan (in Portuguese, Plano Nacional de Desenvolvimento) [9]. In 2011, the pesticide market in this country was considered the largest in the world, representing 16% of the global market according to the National Health Surveillance Agency (in Portuguese, Agência Nacional de Vigilância Sanitária, ANVISA) [10]. Over the past 50 years, pesticides had been used to increase the food quantity and quality for a growing world population. While worries about their adverse effects in nontarget organisms, including humans, had been also increased [11]. These chemicals, while having a beneficial effect toward agricultural production, are alien to nature and can produce changes and imbalances [12]. Many of them are toxic not only to insects and harmful pests but also to other

development of bioremediation methodologies using these microorganism.

transformation

194 Advances in Bioremediation of Wastewater and Polluted Soil

**1. Introduction**

the target organism [4].

1940s [8].

**1.1. Pesticides**

The age of the organochlorine compounds was started in 1948 with the Nobel Prize in Physiology or Medicine delivered to Paul Müller, who condensed chlorobenzene to synthesize *p*-dichlorodiphenyltrichloroethane (DDT), a high effective insecticide [22]. Since then, new types of organochlorines compounds had been developed and extensively used (Figure 1). However, the harmful effects of those compounds, such as persistence, toxicity, and bioaccu‐ mulation had been also reported [23].

In 1962, the American biologist Rachel Carson published the book "Silent Spring" alerting for the damage that insecticides, especially the DDT, could cause. Despite having been the target of much criticism, the publication was fundamental for the prohibition of organochlorine pesticides in the United States in the early 1970s [17]. Although the use of organochlorine pesticides in agriculture was banned, elimination methods are still studied since these compounds had been widely used from 1960 to 1980, and thus, a toxic waste accumulation occurred in various ecosystems around the world [24].

The organochlorine pesticides are highly thermostable compounds with cyclic structures [26] mainly formed by hydrogen, carbon, and chlorine [27] and recognized as the most toxic and persistent pollutants among organic compounds [28-29]. These compounds dissolve well in

**Figure 1.** Synthetic organochlorines used as insecticides in the early days (Adapted from Santos et al. [25]).

lipids (fat-soluble), and favors its accumulation in adipose tissues of animals [23]. Thus, they are biomagnified through the biological chain [30], affecting the health of the top predators, including humans [31]. Additionally, organochlorine compounds may interfere in the normal functions of the endocrine system and disturb the reproduction in animals, since they show estrogenic and carcinogenic activity [32-33].

Organochlorine pesticides and some of their physical and chemical characteristics are described in Table 1. Among them, pentachlorophenol (PCP) is one of the most studied organochlorine compounds, because it slightly dissolves in water and has strong solubili‐ ty, toxicity [34], volatility, ability to release dioxin (and its derivatives), and resistance to biodegradation [35].



**Table 1.** Physical and chemical characteristics of the main organochlorine pesticides (Adapted from Almeida *et al*. [36]).

#### **1.3. Pentachlorophenol**

lipids (fat-soluble), and favors its accumulation in adipose tissues of animals [23]. Thus, they are biomagnified through the biological chain [30], affecting the health of the top predators, including humans [31]. Additionally, organochlorine compounds may interfere in the normal functions of the endocrine system and disturb the reproduction in animals, since they show

hexane isomers

Cl

dieldrin

Cl

Cl Cl

Cl Cl

Cl

Cl

Cl

Cl

Cl

chlordane

OH

Cl

Pentachlorophenol

Cl

Cl Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Organochlorine pesticides and some of their physical and chemical characteristics are described in Table 1. Among them, pentachlorophenol (PCP) is one of the most studied organochlorine compounds, because it slightly dissolves in water and has strong solubili‐ ty, toxicity [34], volatility, ability to release dioxin (and its derivatives), and resistance to

**Compound CAS number Solubility in water Steam pressure**

**309-00-2 27 µg L–1**

**60-57-1 140 µg L–1**

**at 25°C**

**at 20°C**

**2.31 × 10 mm Hg at 20°C**

**1.78 × 10 mm Hg at 20°C**

estrogenic and carcinogenic activity [32-33].

aldrin

Cl Cl

CCl3

Cl Cl

Cl Cl

196 Advances in Bioremediation of Wastewater and Polluted Soil

Cl

O

DDT hexachlorocyclo-

Cl

**Figure 1.** Synthetic organochlorines used as insecticides in the early days (Adapted from Santos et al. [25]).

Cl

Cl

biodegradation [35].

aldrin

Cl Cl

dieldrin

O

Cl Cl

Cl Cl

Cl

Cl

Cl

Cl

Cl Cl

PCP is used as an insecticide, fungicide, herbicide, and wood preservative [37]. Moreover, PCP is a by-product of the paper bleaching, disinfection of water containing phenols with chlorine or sodium hypochlorite, incineration of municipal solid waste and other processes [38-39]. PCP can be found in the air in the form of steam, adsorbed in soil and sediments, in surfaces and groundwater in its ionized salt form [40]. Table 2 shows some physical and chemical properties of PCP.


**Table 2.** Physical and chemical properties of the PCP (Source: adapted from EPA [41]).

The PCP is produced by two different routes, i.e., the gradual chlorination of phenols in the presence of catalysts (ferric chloride or anhydrous aluminum chloride) and by dechlorination of hexachlorobenzene [42]. According to the Environmental Sanitation Technology Company of São Paulo State (in Portuguese, Companhia de Tecnologia e Saneamento Ambiental do Estado de São Paulo, Cetesb), PCP is a white solid insoluble in water, but highly soluble in oils and fat compounds. The commercial reagent of PCP contains about 85% of active ingredient, 6% of tetrachlorophenol, 6% of other chlorinated phenolic compounds and inert materials [43]. Other impurities are dioxins (tetra-, hexa-, and octachlorodibenzene-*p*-dioxin) and hexachlor‐ obenzene as by-products of manufacture, which can be easily released to the environment. PCP is no longer marketed in Brazil, but pentachlorophenate, which is a water-soluble persistent product formed by the neutralization with sodium hydroxide, can be easily obtained because it is still used as wood preservative [44-45]. The high solubility of the sodium salt in water enables the persistence for long periods in water bodies, increasing the intoxication level [46]. Fish absorb PCP thorough their gills and alimentation, and then contaminate humans through the food chain [47]. According to Ondarza et al. [48], this accumulation in fish reflects the environment contamination degree.

According to the United States Environmental Protection Agency [41], several studies have provided data on PCP levels in human blood and urine (samples from general population or those with known PCP exposure), indicating that the main route of PCP absorption is inhala‐ tion during production and handling [49]. It can be easily absorbed by skin and gastrointestinal tract, and then dissipated throughout the body. Consequently, PCP is concentrated in heart, brain, adrenal glands, adipose tissue, liver, and kidneys [50], in which they cause serious damage and cancer [51].

Even with the prohibition of the PCP use in Brazil since 1985 (Ministry of Agriculture in Portuguese: Ministério da Agricultura), many areas remain contaminated. The main reason of the pollution is the indiscriminate use of PCP for several decades [38]. Studies show that PCP residues are still measured at high level in several environmental matrices, such as soil, water, sediment, organic matter suspension, atmosphere, and even in many organ‐ isms [52-53]. Thus, the use of biological degradation techniques is very important because these methodologies promote the complete mineralization of this compound or conver‐ sion to harmless products [54].

#### **1.4. Microbial biodegradation of pesticides**

CAS number 87-86-5 Molecular formula C6H Cl5O Molar mass 266.34 g mol–1 Melting point 190–191° C Boiling Point 309–310° C (dec.) Appearence White crystalline solid

198 Advances in Bioremediation of Wastewater and Polluted Soil

Density 1.978 g cm–3 Vapor density 9.20 (air = 10) Solubility in water 0.020 g.L–1 at 30<sup>ο</sup>C Henry's Law constant 2.45 × 10–8 atm-m3

**Table 2.** Physical and chemical properties of the PCP (Source: adapted from EPA [41]).

the environment contamination degree.

damage and cancer [51].

The PCP is produced by two different routes, i.e., the gradual chlorination of phenols in the presence of catalysts (ferric chloride or anhydrous aluminum chloride) and by dechlorination of hexachlorobenzene [42]. According to the Environmental Sanitation Technology Company of São Paulo State (in Portuguese, Companhia de Tecnologia e Saneamento Ambiental do Estado de São Paulo, Cetesb), PCP is a white solid insoluble in water, but highly soluble in oils and fat compounds. The commercial reagent of PCP contains about 85% of active ingredient, 6% of tetrachlorophenol, 6% of other chlorinated phenolic compounds and inert materials [43]. Other impurities are dioxins (tetra-, hexa-, and octachlorodibenzene-*p*-dioxin) and hexachlor‐ obenzene as by-products of manufacture, which can be easily released to the environment. PCP is no longer marketed in Brazil, but pentachlorophenate, which is a water-soluble persistent product formed by the neutralization with sodium hydroxide, can be easily obtained because it is still used as wood preservative [44-45]. The high solubility of the sodium salt in water enables the persistence for long periods in water bodies, increasing the intoxication level [46]. Fish absorb PCP thorough their gills and alimentation, and then contaminate humans through the food chain [47]. According to Ondarza et al. [48], this accumulation in fish reflects

According to the United States Environmental Protection Agency [41], several studies have provided data on PCP levels in human blood and urine (samples from general population or those with known PCP exposure), indicating that the main route of PCP absorption is inhala‐ tion during production and handling [49]. It can be easily absorbed by skin and gastrointestinal tract, and then dissipated throughout the body. Consequently, PCP is concentrated in heart, brain, adrenal glands, adipose tissue, liver, and kidneys [50], in which they cause serious

Even with the prohibition of the PCP use in Brazil since 1985 (Ministry of Agriculture in Portuguese: Ministério da Agricultura), many areas remain contaminated. The main reason of the pollution is the indiscriminate use of PCP for several decades [38]. Studies show that PCP residues are still measured at high level in several environmental matrices, such as

mol–1

The microorganisms are adaptable to adverse conditions and find ways to grow even in challenging environments [55]. Its potential for biotechnological applications are justified by their tolerance to extreme environmental conditions, rapid growth, low cultivation cost [56], and mainly by their enzymes, which can transform a wide variety of nonnatural chemical compounds [57].

Microorganisms can degrade xenobiotics contained in dyes, cosmetics, detergents, medicines, agricultural chemicals and can mineralize and degrade pesticides to nontoxic compounds [58, 59]. Therefore, microbial biodegradation is an effective method to reduce the harmful effects of pesticides. Biodegradation is considered the main process of pesticides elimination in soil [60] since microorganisms are capable of use these compounds as nutrients source for its enzyme-catalyzed transformations, which lead to changes of structure and toxicological properties and consequently, its polluting potential [61].

Organochlorine compounds are known to undergo dehydrochlorination, oxidation, dechlori‐ nation, rearrangement, hydrolysis, and photochemical reactions [65]. Among the pathways observed in microorganisms, the dechlorination under anaerobic condition and dehydrogen‐ ation under aerobic condition are the most important [18].

The selection of an appropriate microorganism is an essential step to perform a microbial biotransformation. If a microorganism can proliferate efficiently in environments with high concentrations of certain pollutants, such strain might be more adapted for the remediation of these contaminants [62]. Different bacterial and fungi genera had been used as efficient pesticides metabolizing organisms such as *Rhodococcus*, *Pseudomonas* and *Flavobacterium* [61], *Lentinula edodes*, *Phlebia radiata*, *Phanerochaete chrysosporium* [63], *Trametes hirsutus*, *Phanero‐ chaete sordia*, and *Cyathus bulleri* [64].

In the biodegradation of organochlorine pesticides, some bacterial genera have been proven to be good biocatalysts, i.e., *Klebsiella* [66], *Staphylococcus*[67], and *Pseudomonas*[68]. Some fungi are also effective, i.e., basidiomycetes [69, 70] and white-rot-fungi, such as *Trametes villosa* [71], *Phaneroachaete chrysosporium*, *P. sordida* [72], *Phlebia radiata* [73], which are commonly used to biodegrade organochlorine compounds. But there are also reports of other fungal species involved in biodegradation of these compounds, i.e., *Trichoderma harzianum* [74], *Aspergillus niger* [75], and *Fusarium verticillioides* [76] with excellent results.

#### **1.5. Biodegradation of PCP**

The degradation of PCP in the environment can occur through chemical, microbiological, photochemical, electrochemical, and thermal processes [77, 78]. Microbial decomposition is an important removal mechanism of this compound [78]; however, PCP causes oxidative phosphorylation and membrane cell disruption. Therefore, its toxicity slows biodegradation because of the growth inhibition effects on microorganisms [79].

Despite having these biodegradation unfavorable attributes, some microorganisms have the ability to use PCP and its metabolites as carbon and energy sources [80, 81]. Among the reported species, *Pseudomonas fluorescens* (TE3) [82], *Pseudomonas aeruginosa* (PCP2) [83], *Serratia marcescens*[84], *Pseudomonas stutzeri* (CL7) [81], and *Comamonas testosteroni* (CCM7350) are important examples [85].

Figure 2 shows the biodegradation pathway of PCP by *Sphingobium chlorophenoculium* ATCC 39723 [86]. This strain can degrade PCP to carbon dioxide and water (Figure 2).

**Figure 2.** Biodegradation pathway of PCP by the *Sphingobium chlorophenolicum* ATCC 39723 bacteria (adapted from Cai and Xun [86]).

Usually, metabolic transformations in biological systems can be divided into two phases. The reactions of phase I promote changes in xenobiotics such as oxidation, reduction, hydrolysis, and other reactions. After this step, the phase II reactions known as conjugations occurs, in which endogenous groups, which are usually polar and present in abundance *in vivo*, are added to the xenobiotic resulting in more polar products (except in alkylation reactions) and therefore, more easily eliminated compounds. It is noteworthy that conjugated xenobiotics can undergo inverse reactions and regenerate the original compound [87]. Thus, the compound can be degraded (into smaller molecules which can be toxic or not), absorbed, adsorbed, or conjugated during the biodegradation [88].

There are many reports involving the use of terrestrial fungi in the biodegradation of PCP. Among them, white-rot fungi are highly tolerant to toxic compounds and are widely used in biodegradation techniques [71]. These fungi are effective in the degradation of PCP by having ligninolytic and peroxidase enzymes [89] that act by generating free radicals [90], which can also degrade a variety of recalcitrant pollutants (Figure 3) [91].

important removal mechanism of this compound [78]; however, PCP causes oxidative phosphorylation and membrane cell disruption. Therefore, its toxicity slows biodegradation

Despite having these biodegradation unfavorable attributes, some microorganisms have the ability to use PCP and its metabolites as carbon and energy sources [80, 81]. Among the reported species, *Pseudomonas fluorescens* (TE3) [82], *Pseudomonas aeruginosa* (PCP2) [83], *Serratia marcescens*[84], *Pseudomonas stutzeri* (CL7) [81], and *Comamonas testosteroni* (CCM7350)

Figure 2 shows the biodegradation pathway of PCP by *Sphingobium chlorophenoculium* ATCC

Cl

OH Cl Cl

OH Cl Cl

2,6-dichloro*p*-hidroquinone

Cl CO2H

OH

2-chloromaleic acid

CO2H

OH

2,3,6-trichloro*p*-hidroquinone

CO2H

maleic acid

CO2H

O

**Figure 2.** Biodegradation pathway of PCP by the *Sphingobium chlorophenolicum* ATCC 39723 bacteria (adapted from Cai

Usually, metabolic transformations in biological systems can be divided into two phases. The reactions of phase I promote changes in xenobiotics such as oxidation, reduction, hydrolysis, and other reactions. After this step, the phase II reactions known as conjugations occurs, in which endogenous groups, which are usually polar and present in abundance *in vivo*, are added to the xenobiotic resulting in more polar products (except in alkylation reactions) and therefore, more easily eliminated compounds. It is noteworthy that conjugated xenobiotics can undergo inverse reactions and regenerate the original compound [87]. Thus, the compound can be degraded (into smaller molecules which can be toxic or not), absorbed, adsorbed, or

OH

39723 [86]. This strain can degrade PCP to carbon dioxide and water (Figure 2).

Cl

OH

Cl Cl

Cl

CO2H

3-oxoadipate

O

conjugated during the biodegradation [88].

OH

TCHQ

CO2H

because of the growth inhibition effects on microorganisms [79].

are important examples [85].

200 Advances in Bioremediation of Wastewater and Polluted Soil

OH

Cl Cl

Cl

PCP

Cl

CO2 + H2O

and Xun [86]).

Cl

**Figure 3.** Examples of recalcitrant compounds biodegraded by ligninolytic and peroxidase enzymes: lignin monomers, polycyclic aromatic hydrocarbons (PAHs), and halogenated compounds (Adapted from Pointing [90]).

The ligninolytic extracellular activity of some fungal enzymes is considered a promising method for PCP degradation [92, 94]. The *Phanaerochaete chrysoporium* [95, 96], as well as *Phlebia brevispora* [97], *Phlebia radiata*, *Trametes versicolor* [98], and *Mucor plumbeus* [99] showed great ability to degrade organopollutants (including PCP). Fungal species belonging to the genus *Trichoderma*, such as *T. virgatunil*[100] and *T. harzianum*[74], were efficient in the mineralization of PCP and *Anthracophyllum discolor* mineralized this polutant in reactors containing soil slurry according to Rubilar [101]. Figure 4 shows the PCP biodegradation pathway by *A. discolor*. It is noteworthy that this pathway is different from that by *S. chlorophenolic* ATCC 39723.

The use of filamentous fungi in biodegradation is increasing considerably in recent years, due to the high rates of biodegradation, sortion, and resistance in adverse environmental condi‐ tions [102]. According to Sankaran et al. [103], the interest in the use of filamentous fungi in bioremediation is due to high species diversity, high resistence for recalcitrant compounds, and high production of extracelular enzymes.

**Figure 4.** Degradation of PCP by the fungus *Anthracophyllum discolor* (Source: modified from Rubilar et al. [101]).

#### **1.6. Marine fungi**

The marine environment covers more than three quarters of the Earth's surface and is a promising source of new enzymes [104]. These enzymes show great potential for use in biocatalytic reactions by possessing unique characteristics related to the marine environment. In recent years, a wide variety of enzymes and microorganisms with specific activities have been isolated from marine environments [105] and have been extensively studied, particularly proteases, carbohydrases, oxidoreductases, peroxidases [106].

The words "marine fungi" are not derived from a taxonomic class and they are not classified by their physiological characteristics. These fungi considered as an ecological group, and the most suitable definition was proposed by Kohlmeyer and Kohlmeyer [107]: "Mandatory marine fungi are those that grow and sporulate exclusively in a marine or estuarine habitat; facultative marine fungi are those from freshwater or terrestrial water environments and are able to grow and even sporulate in the marine environment " [108]. In the marine environment, many fungi strains can be found in a wide variety of habitats such as open sea, sediment, mangroves, surface of wood, shells of molluscs, corals, marine vertebrates and invertebrates, on the surface or interior of algae and even in hydrothermal vents. The variety of habitats also influences their metabolic diversity, which contributes to their potential use as source of enzymes and bioactive molecules [109].

Unlike terrestrial fungi, which were initially exploited for drug discovery, marine fungi have attracted the attention of researchers as a source of new natural products and enzymes [110]. Marine fungi are adapted to high salinity and extreme conditions, developing attributes that give them the ability to produce a different enzymatic metabolism from their respective representatives from the terrestrial environment [111]. Researches had been generally focused on biological activities such as antibiotic and by marine fungi [112]. However, recently they have been investigated for dechlorination and detoxification of effluents [113], biodegradation of polycyclic aromatic hydrocarbons [114], lignin [115], pesticides [116, 117], and polyethylene [118], and more recently, studies on biocatalytic reactions for organic synthesis [106].

Filamentous fungi *Aspergillus sydowii*, *Penicillium raistrickii*, *Trichoderma* sp., and *Penicillium miczynskii* isolated from marine environment and cultured in artificial sea water were capable of catalyzing the hydrolysis of benzyl glycidyl ether and allyl glycidyl ether [119, 62]. Bonugli-Santos et al. [120] found interesting results in a study of ligninolytic enzyme production by the marine fungi *Aspergillus sclerotiorum* CBMAI 849, *Cladosporium cladosporioides* CBMAI 857, and *Mucor racemosus* CBMAI 847. The marine fungi *Microsphaeropsis* sp., *Acremonium* sp., and *Westerdykella* sp. promoted the biodegradation of esfenvalerate (pyrethroid pesticide) with formation of several metabolites [121].

The enzymatic reactions catalyzed by marine-derived fungi can be carried out in laboratory using artificial seawater. Studies have shown that marine bacteria and fungi cultured in laboratory have specific requirements of salts, especially the sodium ions, potassium, magne‐ sium, and chloride [122, 119]. According to Rateb and Ebel [123], for biotransformation studies and production of secondary metabolites, marine-derived fungi strains have been isolated mainly from inorganic substrates, plants, marine invertebrates, and vertebrates. In this context, studies on enzyme production by filamentous marine-derived fungi are important for future applications in bioremediation techniques. Thus, this work aimed the exploration of the potential biodegradation of the pesticide PCP by strains of marine-derived fungi isolated from a marine invertebrate, the ascidian *Didemnun ligulum*.
