Strategies for Bioremediation of Organic and Inorganic Pollutants

Maria S. Fuentes, Verónica L. Colin, Juliana M. Saez

• Publisher: CRC Press
• Year: 2018
• ISBN:
  9781351857376
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

Increased awareness surrounding environmental protection has prompted the development of more ecofriendly technologies. This book provides useful information on technologies based upon the use of biological agents for environmental clean-up, including bacteria, yeast, fungi, algae, and plants. Some chapters refer to the direct application of products derived from plants and microorganisms for designing strategies of environmental remediation. The combination of strategies helps in efficient removal of pollutants generated from anthropogenic activities with minimal environmental impact. This book is meant for professionals involved in environmental technology and waste management.

1

Agro-industrial Wastewaters Bioremediation by Ligninolytic Macrofungi

Pablo M. Ahmed,^1,* María del M. Rosales Soro,^2,a, Lucía I.C. de, Figueroa^2,3,b and Hipóito F. Pajot^2,c

Introduction

Industrial activity has always resulted in some class of contamination, either solid waste, wastewater or gaseous pollution. The agro-industrial wastes consist of many and varied residues from agriculture and food industry and are worldwide produced at an estimated rate of thousand million tons per year. Although several agro-industrial residues can be disposed of safely in the environment due to its biodegradable nature, the vast quantities in which they are generated makes it necessary to look for disposition mechanisms involving the production of goods or services. Biotechnology offers many feasible alternatives to the disposal of agro-industrial wastes, allowing seeing the problems of waste disposal under a new light, as a source of valuable resources for the production of fuels, feeds, medical, pharmaceutical and industrial products.

Microbial processes are being examined as viable remediation technologies to fight environmental pollution, thus a variety of cleanup technologies have been put into practice and novel methods of bioremediation for the treatment of agro-industrial wastes are currently being worked out. An emerging field is the exploitation of waste’s nutritive potential for the production of various high-value compounds.

This chapter presents a summary of the most studied macrofungi in the bioremediation of agro-industrial wastes, the processes involved as well as the main characteristics of important agro-industrial wastewaters and the simultaneous use of its nutritional potential for the production of several high-value compounds. The role of fungal enzymes in the degradation and transformation of phenols, lignin and related compounds in olive mill wastewater, pulp and paper mill effluents, and sugar crops stillages are discussed in detail. The most recent knowledge on these liquid wastes, in terms of their composition, obtaining and treatment methods, with special emphasis on the bioremediation, employing a specific fungi group—ligninolytic macrofungi—are also presented.

Mycotransformation, an Efficient Pollutant Removal Biotechnology

Bioremediation, also known as biotreatment, bio-reclamation or bio-restoration, is a process that utilizes the metabolic potential of living organisms such as bacteria, fungi, algae, and plants, to clean up contaminated environments and detoxify, degrade or remove environmental pollutants. Bioremediation is a promising, relatively efficient and cost-effective technology for the treatment of highly polluted industrial wastewaters with a positive environmental impact (Asamudo et al. 2005, Pant and Adholeya 2007a). According to Kulshreshtha (2012), current approaches about bioremediation are based on two main principles: metabolism or absorption of pollutants by living organisms. The organisms used in bioremediation may be autochthonous (indigenous), allochthonous (non-indigenous), or genetically modified organisms. Microorganisms can be used for bioremediation purposes in both in situ and ex situ conditions. With in situ techniques, the polluted site is treated in place; however, in ex situ techniques, samples from polluted sites are collected and transferred to the laboratory for its treatment (Rhodes 2014).

Fungi are a diverse group of organisms ubiquitous in the environment. They can exist and survive in almost every habitat and may play vital roles in all ecosystems. Fungi have the ability to regulate the flow of nutrients and energy through their mycelia networks and are known to degrade, or deteriorate, a wide variety of materials and compounds in processes referred as myco-degradation and myco-deterioration (Tiwari 2015). Fungal degradative activities against different kinds of wood, stored paper, textiles, plastics, leather, and electron insulating and various wrapping materials are well known. In fact, these are the unique microorganisms that can be employed in the complete mineralization of several wastes and wastewaters (Singh 2006). Filamentous fungi are also used to entrap and immobilize organic and inorganic particles of stillages, forming larger pellets or flocs, which enhance the subsequent separation and biodegradation (Alam and Razi 2003). In a similar way, fungi modify the structure of biosolids enhancing their bioseparation, dewaterability, and filterability (Mannan et al. 2005).

Environmental engineers all over the world have to solve problems of wastes and wastewaters. Fungal treatment of wastes in nature has been known for centuries. Due to their ubiquitous presence, fungi are capable of acclimatizing to some types of wastes, and growing in variable environmental conditions including the use of different carbon and nitrogen sources, different inoculum doses and time, as well as in static or agitated culture conditions. Some molds, yeasts, and filamentous fungi are highly tolerant to acidic or alkaline environment, while others are psychrophilic growing at temperatures near or below 0°C, whereas certain psychrotolerant fungi have the ability to survive at the very low temperature of −40°C. On the contrary, thermophilic fungi can grow above 40°C and may be cultivated in minimal media with growth yields and metabolic rates comparable to those of mesophilic fungi. Thus, fungi could thrive in the harsh conditions that characterize most industrial wastewaters and have been extensively used to remove heavy metals from liquid effluents and to mineralize phenols, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, chlorinated pesticides, dyes, biopolymers, and other substances (Anastasi et al. 2013, Martorell 2014, Singh 2015, Haritash and Kaushik 2016).

Valorization of Agro-industrial Wastewaters

Industries of olive oil, starch, sugar cane, cotton bleaching, pulp and paper processing, and fruit packaging, among others, produce several billion liters of colored, toxic and harmful wastewaters over the world annually (Coulibaly et al. 2003). Generally, these industries generate wastes with similar features and in some cases at the same time of the year. For this reason, a common process to treat their residues is of great interest. There is a growing concern around the world regarding environmental pollution caused by this kind of agroindustrial wastewaters. In the last decade, the European Commission was established to influence the environmental regulations and technical aspects of the regulation of industrial wastewaters discharge, while, the United States Environmental Protection Agency (EPA) developed and implemented related politics and regulations more than a decade earlier (Singh 2006).

As a result of the implementation of protectionist environmental policies, the conversion of industrial wastewaters to valuable materials and energy is emerging as a promising trend that pursues the safe reuse of wastes for sustainable development as a manner of stopping the depletion of natural resources and the global climate change.

Agro-industrial wastewaters can provide us with environmental and economic benefits (nee’ Nigam et al. 2009). Liquid effluents could be biotechnologically transformed into biofuels, microbial biomass or chemicals, or used as cheap and abundant sources of substances, such as polyphenols, exopolysaccharides, organic acids, catalysts, oligosaccharides, etc., for the cosmetic, nutraceutical, food conservation, packaging, pharmaceutical and medical industries (Zhang 2008, Sánchez 2009, ElMekawy et al. 2014).

Agriculture wastewaters such as sugar crops molasses, distilleries vinasses and the residues of milling processes are rather promising substrates for the production of added-value by-products because besides being cheap and abundant, they require minimal supplements to allow microbial growth. This kind of residues serves as a storehouse of carbon, energy and other macronutrients such as nitrogen, phosphorous, and sulfur, and growth factors as minerals and vitamins (Vandamme 2009, Santana-Méridas et al. 2012).

Molasses are produced by the sugar industry from cane or beet crops; the product is actually the mother liquor separated from the crystallized sucrose. Typical molasses have 50–55% total fermentable sugar by weight and it is used extensively in the production of bulk goods such as yeast, ethanol, poly-γ-glutamic acid, citric and succinic acids, industrial enzymes, and many others (Liu et al. 2008, Gopal and Kammen 2009, Zhang et al. 2012).

Vinasse is a liquid waste generated in the distillation of ethanol after fermentation of the molasses or juice from sugar crops, such as sugarcane and beet. Despite having variable concentration of potassium, phosphates, sulfates, calcium, iron, sodium, chlorides, carbon sources, nitrogen and other trace elements, several investigations have shown that vinasses can be used as culture media component for the production of microbial biomass proteins, lipids or enzymes, due to its nutritional characteristics (Aguiar et al. 2010, España-Gamboa et al. 2011).

Olive mill wastewater contains a variety of assimilable carbon sources, vitamins and minerals and therefore it can be regarded as fermentation medium for the production of high-added value products from industrial importance, e.g., enzymes, organic acids, exopolysaccharides, single cell oils, etc. (Yousuf et al. 2010, Bellou et al. 2014, Arous et al. 2016).

Pulping and bleaching plant effluents can be tranformed in valuable compounds (biological metabolites, or others like lignin and lignin-derivates), which have antioxidants properties or utility in pesticide and pharmaceutical industry (Arun and Eyini 2011, Lavoie et al. 2011).

Wastewaters Fungal Bioremediation

Fungi have the ability to mineralize, release and store several materials that are toxic to other microorganisms. In addition, fungi are a common source of secondary metabolites such as protein and valuable biochemicals products for medicinal, agricultural and industrial importance including antibiotics, immunosuppressants, anticancerous agents, enzymes and organic acids, among others (Tiwari 2015). Yeasts and filamentous fungi are also used extensively to reduce the chemical and biochemical oxygen demand of a wide variety of food and agriculture-processing wastewaters with the concomitant production of protein or fodder yeasts and fungi. Fungal treatment of wastewaters dated back to the ’60s (Singh 2006). Fungal bioremediation not only converts the wastewater organics into added-value products such as amino acids, enzymes, dyes, organic acids, organic alcohols, and others (van Leeuwen et al. 2003), but it also produces highly dewaterable fungal biomass, which can be used as a source of animal feed and potentially in human diets (Guest and Smith 2002, Zheng et al. 2005).

In any ecosystem, fungi are among the major decomposers of plant polymers such as cellulose, hemicelluloses, and lignin. Fungal ligninolytic enzymes like manganese peroxidase, lignin peroxidase and laccase have been used to biodegrade recalcitrant compounds such as phenolic compounds, dyes, polycyclic aromatic hydrocarbons, explosives, and drugs among others, through nonspecific enzymatic oxidation reactions (D’Annibale et al. 2005, Chen and Ting 2015).

Ethanol Distilleries Vinasse

A variety of agro-industrial residues is nowadays being fermented worldwide to produce ethanol, used as fuel. The production of ethanol as a biofuel has increased in the latest years. The fuel ethanol market grew from less than a billion liters in 1975 to more than 39 billion liters in 2006. In 2008, globa...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Preface
• 1. Agro-industrial Wastewaters Bioremediation by Ligninolytic Macrofungi
• 2. Bioremediation of Lignocellulosic Waste Coupled to Production of Bioethanol
• 3. Recovery of Sugarcane Vinasse by Microbial Pathways: An Integral Approach
• 4. Use of Immobilized Biomass as Low-Cost Technology for Bioremediation of PAHs Contaminated Sites
• 5. Biosorption of Dyes by Brown Algae
• 6. Strategies for Biodegradation and Bioremediation of Pesticides in the Environment
• 7. Pesticide Bioremediation: An Approach for Environmental Cleanup Using Microbial Consortia
• 8. Mycoremediation: Fungal Mediated Processes for the Elimination of Organic Pollutants
• 9. Pesticides in the Environment: Biobed Systems as an Innovative Biotechnological Tool to Minimize Pollution
• 10. Hexachlorocyclohexane: Sources, Harmful Effects and Promising Bacteria for its Bioremediation
• 11. Actinobacteria as Bio-Tools for Removing and Degrading α-, β- and γ-Hexachlorocyclohexane
• 12. Mining and Mine Tailings: Characterization, Impacts, Ecology and Bioremediation Strategies
• 13. Phytomanagement of Metal-Rich and Contaminated Soils: Implicated Factors and Strategies for its Improvement
• 14. Bioremediation of Heavy Metals by Immobilized Microbial Cells and Metabolites
• 15. Hexavalent Chromium Removal Related to Scale-up Studies
• 16. Contribution of Genomic and Proteomic Studies toward Understanding Hexavalent Chromium Stress Resistance
• 17. Effects of Environmental Factors on Bioremediation of Co-Contaminated Soils Using a Multiresistant Bacterium
• Index