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Über dieses Buch

This book explores the concept and methods of waste management with a new approach of biological valorization. Waste valorization is a process that aims to reduce, reuse, and recycle the waste into usable, value-added, and environmental benign raw materials which can be a source of energy. The book brings together comprehensive information to assert that waste can be converted into a resource or a raw material for value addition. Waste valorization imbibes the natural recycling principles of zero waste, loop closing, and underlines the importance of sustainable and environmentally friendly alternatives. Drawing upon research and examples from around the world, the book is offering an up-to-date account, and insight into the contours of waste valorization principles, biovalorization technologies for diverse group of wastes including agricultural, municipal, and industrial waste. It further discusses the emerging paradigms of waste valorization, waste biorefineries, valorization technologies for energy, biofuel, and biochemical production. The book meets the growing global needs for a comprehensive and holistic outlook on waste management. It is of interest to teachers, researchers, scientists, capacity builders and policymakers. Also, the book serves as additional reading material for undergraduate and graduate students of biotechnology and environmental sciences.



1. Microbial Valorization of Coir Pith for Development of Compost and Bioethanol Production

Coco pith, an agricultural by-product of coir industry, is a dust left after the extraction of coir fibers from coconut husk. It is accumulated outside the coir industries as huge heaps, which usually becomes an environmental hazard. It is degraded very slowly due to its high lignin and cellulose content. The tannins and phenols are leached out from coir pith heaps by rains which enter the soil and aquatic ecosystems leading to loss of soil fertility and have adverse effect on soil and aquatic biodiversity. Thus, the safe disposal of coir pith is the need of hour which can be achieved by its conversion into value-added products like compost and bioethanol. Due to its rich nutrient content, it has a good prospective as compost. The microbial valorization of coir pith has been proved not only to enrich nutrients in the agricultural soil, but also to increase the pathogen resistance and will surely resolve the environmental pollution problems. The high cellulose and hemicellulose content of coco pith make it a suitable candidate for conversion into bioethanol. This chapter will outline the future prospects in the processing and conversion of coir pith into commercially viable compost and bioethanol.
Tripti Malik, Seema Rawat

2. Transforming the Lignocellulosic Biomass into High Value-Added Bioproducts

Lignocellulosic biomass comprehends the most abundant and renewable material in the world, being its efficient fractionation crucial to develop economically viable biorefineries. Chemical, physical, physical-chemical, biological, or enzymatic conversion can be used as strategies to produce important bioproducts as carbohydrates, bioactive compounds, and lignin derivatives. Carbohydrates as xylose and glucose can be used for food, chemical blocks, materials, and biofuels production by microorganisms like the yeast Spathaspora passalidarum for the production of xylitol, ethanol, acetoin, and 2,3-butanediol. Besides that, the lignocellulosic biomass is an important substrate for the production of several enzymes such as glycohydrolases (cellulases and hemicellulases) and oxidoreductases (laccase, peroxidases, and polysaccharide monooxygenases). Hemicellulases are necessary enzymes to achieve the required degree of polymerization of xylooligosaccharides, a new class of prebiotics extracted from the hemicelluloses fraction. Chemicals derived from lignin have found applications in various industries including nanoparticles, composites, antioxidants, polymer, among others. The focus of this chapter is to review the state of the art with regard of the characterization and valorization of lignocellulosic feedstock, as well as the process involving in the biomass fractionation, bioproducts recovery, and production.
Jaciane Lutz Ienczak, Patrícia Poletto, Diogo Robl, Sarita Cândida Rabelo

3. Microbial Mediated Valorization of Lignocellulose: A Green Technology for Bioethanol Production

In the modern world, the attention is raised for the development of newer technologies for the transformation of biological wastes into biofuels as an alternative option of exhaustible petroleum or other sources. The organic parts of agricultural wastes, forest residues, food wastes, and municipal and industrial wastes contain an unlimited source of lignocellulosic biomass which could potentially be used for generating second-generation biofuels such as “bioethanol.” Microorganisms play an important role in all probable steps intended for lignocelluloses hydrolysis. The greener technological approach for green fuel production through application of microorganisms is a sustainable and renewable approach which is carried out in three steps such as (a) hydrolysis of lignin; (b) hydrolysis of cellulose and hemicelluloses; (c) fermentation of glucose to ethanol. The high production of ethanol is the need of the cotemporary world and therefore it becomes necessary to explore different microorganisms having a high potential for ethanol yield. Moreover, introducing metabolic engineering techniques is the current advancement for development of modified microbial cells for enhanced production of ethanol from lignocellulosic biomass. The present chapter focuses on the valorization of lignocelluloses waste through microorganisms and their mechanisms required for bioethanol synthesis from lignocellulosic biomass.
Viabhav Kumar Upadhayay, Amir Khan, Jyoti Singh, Ajay Veer Singh

4. Microbial Valorization: Strategies for Agro-Industry Waste Minimization and Value-Added Product Generation

It is estimated that between 20 and 30% of the total food produced in Europe is wasted, generating associated costs of 143 billion euros per year. These wastes include the non-eaten fraction and food chain by-products, including fish and poultry processing by-products, chitinous bioresources, agricultural, dairy, bakery, winery, and brewery by-products. Many of these wastes are rich in nutrients, even so, their high content in humidity and variability and due fundamentally to the nonexistence of an integral and efficient recovery activity causes their elimination without valorization.
The Waste Directive 2018/851 establishes a series of priorities, starting with reuse, recycling, and recovery, and only eliminating them as a last resort, in order to reduce the environmental and economic impact generated. In this context, valorization via fermentation can be an attractive technology. The objective of the chapter is to review recent developments in microbial valorization of by-products, mainly focused on their revalorization as food, feed, and added-value products. Along the chapter, the possible technologies and drawbacks are exposed, describing the bioconversion agents, possible substrates, and resulting products. As general conclusion, biotransformation is a technology with a huge potential for diverse food by-products’ valorization when the process is correctly designed and optimized.
Jone Ibarruri, Igor Hernández

5. Valorization of Agri-Food Wastes

Agri-food wastes are inherently generated along the food production chain. In this sense, a significant reduction or better management of them could improve food security and also reduce hunger. It should be noted that several global organizations have estimated that food wastes could reach 126 million tons by 2020. Normally, agricultural wastes have been used as animal feeds and fertilizers. Nonetheless, most agricultural wastes have macro- and micronutrients, as well as bioactive compounds that could have a high added value after agricultural waste valorization processes, e.g., the latter can be extracted and incorporated as food additives for the manufacture of active and intelligent packaging, while macromolecules such as carbohydrates, proteins and lipids can lead to obtaining biosurfactants and single cell oils of high added value to be used in food sector. This chapter aims to provide some perspectives and advances in the valuation of agri-food wastes.
Germán Ayala Valencia, Cristiano José de Andrade, Jaciane Lutz Ienczak, Alcilene Rodrigues Monteiro, Tomy J. Gutiérrez

6. Turning Wastes into Resources: Exploiting Microbial Potential for the Conversion of Food Wastes into Polyhydroxyalkanoates

Polyhydroxyalkanoates (PHA) are microbial polyesters produced by a wide range of microorganisms as storage materials. Besides displaying material properties similar to those of petroleum-based plastics, their intrinsic biodegradability makes them “green” candidates for solving plastic pollution issues. The PHA diversity, determined by monomer size as well as by polymer structure, translates into a wide range of material properties finding applications in different sectors. This tunability is due to the complex metabolic network that drives PHA biosynthesis in vivo, which makes every microorganism unique in its producing abilities. Despite such potentialities, the production of PHAs at large scale is hindered by the high cost of carbon substrate necessary to feed PHA producing microbes. In this regard, the use of food wastes as starting feedstock for microbial fermentation would represent a cost-effective way to boost PHA exploitation. This chapter examines the state of the art of food wastes conversion into PHAs, focusing on the strategies applied to develop microbial strains for producing PHAs with tailored properties and high yield. Examples of PHA production based on natural or engineered strains will be examined, and prospects and challenges for the effective exploitation of the processes will be presented.
Iolanda Corrado, Marco Vastano, Nicoletta Cascelli, Giovanni Sannia, Cinzia Pezzella

7. Bacterial Cellulose Production from Agro-Industrial and Food Wastes

Bacterial cellulose (BC) is a popular substitution of plant cellulose due to its higher purity and better properties. It has vast application in various industries, e.g. in paper production, in wound healing, in food packaging and many more. In commercial scale, Gluconacetobacter xylinus is the common species used. Large-scale production of bacterial cellulose, however, is costly with defined chemical medium, i.e. Hestrin and Schramm (HS) medium. Thus, most researchers are seeking alternative from the available wastes in order to reduce the cost. Numerous agro-industrial wastes were utilized as the feedstock for BC production, e.g. pineapple waste, citrus peel waste and extracted date syrup. Most of these agro-wastes are considered as defined medium as the changes of the composition are rather small. The other potential waste that can be used as a feedstock is the household food wastes. Since food waste generation and disposal are major problem in most of the countries, valorization of this waste for BC production may be a win-win situation. Nevertheless, food waste if used as a medium may impose the problem of inconsistent quality of BC as food waste collected typically has inconsistent composition and thus a complex undefined medium. This chapter is centred on comparing the feasibility of using food waste as a low-cost medium to produce BC. Moreover, the effect of food waste medium on the quality of BC is compared with the BC produced from pineapple peel juice medium. In addition, the pre-treatment of food waste and its effect on the properties of the BC are briefly discussed.
G. K. Chua, N. I. F. Mahadi, F. H. Y. Tan

8. Transformation Process of Agricultural Waste to Chemical Production via Solid-State Fermentation

Agricultural waste is generated significantly worldwide. In tropical country like Malaysia, the largest biomass contributing sector is from palm oil plantation. In every palm oil production, the biomass produced was fourfold greater than the palm oil produced. In 2020, the wastes produced reached up to 39 million tons. The wastes comprise of the empty fruit bunches (EFB), palm kernel shell (PKS), mesocarp fiber (MF), palm oil mill effluent (POME), oil palm trunks (OPT), oil palm leaves (OPL), and oil palm fronds (OPF). Most of the wastes are being thrown to landfill, decomposed anaerobically, and led to severe environmental problems. Generally, the agricultural wastes are rich in carbohydrate content which are crucial for fermentation process. Thus, utilization of the waste to useful product, such as chemical production, via fermentation process especially, solid-state fermentation, is vast possibility.
Farhan M. Said, Nor Farhana Hamid, Mohamad Al-Aamin Razali, Nur Fathin Shamirah Daud, Siti Mahira Ahmad

9. Bioleaching from Coal Wastes and Tailings: A Sustainable Biomining Alternative

Mineral coal is one of the most employed natural resources that represent potential environmental issues. The mine tailing contains several valuable minerals such as zinc, molybdenum, vanadium, chromium, iron, and copper. Currently, the most part of mine tailings is disposed at large tailing ponds. Another important tailing from mineral coal is fly ash, the main residue from thermoelectric plants, which may also contain valuable minerals. Currently, the most part of coal fly ash produced is used as raw material for cement fabrication or disposed at ash ponds. In this sense, biomining and bioleaching is an economically and environmentally attractive technology that can be used for metal recovery from residues such as mine tailing and coal ash, in line up with the concept of green chemistry. There are sparse data available on bioleaching of coal ash using either autotrophic or heterotrophic microorganisms. Therefore, the aim of this chapter was to describe the key aspects related to biomining and bioleaching of mine tailing and coal ash, pointing out the state of the art and some future perspectives.
Alexsandra Valério, Danielle Maass, Cristiano José de Andrade, Débora de Oliveira, Dachamir Hotza

10. Recent Advances in Wastewater Sludge Valorization

With a surge in the amount and complexity of wastewater in a rapidly urbanizing world, the challenge of maintaining an efficient treatment of wastewater in a cost-effective and environment-friendly way has to be met. Along with the generation of treated water, the wastewater treatment plant (WWTP) generates huge amount of sludge on daily basis. The handling and disposal of sludge is a major problem associated with WWTPs. The sewage sludge in rich in valuable resources and can also be used for the production of energy. The application of biorefinery concept to wastewater treatment will provide a renewable source for the production of value-added products and bioenergy production. The production of bioplastics, bioflocculant, biofertilizer, biodiesel, biogas, biohydrogen and recovery of phosphorus, enzymes and proteins can be done from sewage sludge. The current trends and challenges in sludge management and biovalorization have been discussed. The biovalorization of sludge will make the overall wastewater treatment process more economical and environmentally sustainable.
Asmita Gupta, Madan Kumar, Shaili Srivastava

11. Agricultural Waste Valorization: An Energy Production Perspective

The energy security, utilization of surplus agricultural waste, and environmental concerns lead to explore the opportunities for valorization of surplus agricultural waste. The agricultural waste is rich in lignocellulose, which can be converted into various forms of energy like ethanol, methane, hydrogen, etc. by adopting different technologies. Therefore, the available surplus agricultural residues can be utilized for sustainable energy production. This will not only produce energy from waste but also save the environment from emissions due to its disposal. The sustainable approach for valorization of agricultural waste can be found by employing the various modellings like life cycle assessment (LCA), life cycle costing (LCC), net energy ratio (NER), techno-economic assessment (TEA), etc.
Shiv Prasad, Dheeraj Rathore, Anoop Singh

12. Microbial Approach for Valorization of Mining Wastes and Tailings: An Overview

Mining is one of the most important economic activities on Earth and has played an important role in human existence. Minerals and metals are crucial for a large number of services and infrastructures that are used by society. However, extensive mining and industrial activities have led to production of large volumes of wastes and management of these materials, such as tailings and waste rock which is an environmental challenge. Moreover, the growing worldwide demand for ores has made developing processes for economic recovery from secondary sources increasingly important. In this scenario, the development of environmentally friendly technologies for valorizing mining wastes is mandatory. This chapter thus intends to provide a current overview of an alternative and green approach for valorization of mining waste and tailings by microbial means, that is, biomining.
Fabíola Fernandes Costa, Érika Tallyta Leite Lima, Yrvana Pereira dos Santos Brito, Deborah Terra de Oliveira, Geraldo Narciso da Rocha Filho, Luís Adriano Santos do Nascimento

13. Microbial Degradation of Lignocellulosic Biomass to Obtain High Value-Added Products

The depletion of the fossil fuels has led to the search for and development of more sustainable and environmental benign energy source. In this sense, the biomass has emerged as alternative resource since biomass is the only source from which it is possible to obtain energy and mainly chemicals that, currently, are obtained from the traditional fossil fuels. The selection of the biomass source is a key parameter to reach a sustainable process. Considering these premises, the lignocellulosic biomass has emerged as a potential alternative source due to its non-edible character as well as its high availability throughout the Earth. Traditionally, the lignocellulosic biomass has been treated thermochemically to obtain high value-added products and energy. However, in the recent past, the microbial treatment of the lignocellulosic biomass has emerged as efficient methodology to solve the problems of energy shortage and the synthesis of valuable products. The aim of this chapter is to evaluate the metabolic process involved in the microbial degradation of lignocellulosic biomass as well as highlight the valuable products obtained through this microbial treatment by alcoholic fermentation and anaerobic digestion.
J. A. Cecilia, C. P. Jiménez-Gómez, C. García-Sancho, P. Maireles-Torres

14. Biorefinery: Potential and Prospects for Utilisation of Biogenic Waste

The biorefinery is considered as a sustainable way of converting different feedstocks into energy-rich products, chemicals and value-added products through a well-established conversion technology. The biorefinery concept emerged with the purpose of efficient utilisation of biomass, waste biovalorization and at the same time to minimise the environmental impacts of waste management. Biorefinery technology enables the production of biomass-derived bioenergy, biofuels and development of circular bioeconomy. The bio-based economy has the potential to mitigate climate change and to achieve sustainable development goals. Biorefining technology refers to the conversion of biomass through processes such as pre-treatment, conversion and processing of products. Biorefinery technology enables thermochemical or biochemical conversion of biomass into bioenergy, biofuels and value-added products. Biorefineries generate low-volume but high-value products and high-volume but low-value products. The biorefineries are classified based on the feedstocks used, conversion processes, platforms or key intermediate products and target products. The feedstocks utilised in the biorefinery are diverse and the sustainability of the biorefinery system depends on (a) availability and characteristics of feedstocks, (b) environmental impacts of feedstock production, (c) amenability and suitability of feedstock for bioconversion and (d) feedstock bioconversion and its contribution to greenhouse gases intensity and energy balance. The feedstocks include “lignocellulosic biomass”, “food wastes”, “algal biomass”, “municipal solid waste”, etc. Based on the feedstocks used, the biorefineries are called as lignocellulosic biorefinery, waste biorefinery, algal biorefinery, etc. However, lignocellulosic waste biorefineries are well studied for its potential and prospects. It gained prominence on account of (a) availability of lignocellulosic waste feedstocks; (b) sustainability of the feedstocks; and (c) diverse value-added chemicals generated from the bioconversion of lignocellulosic waste biomass. The success of biorefineries and development of bio-based industries requires positive intervention from the government in the form of proactive bioeconomy policy.
Shachi Shah, V. Venkatramanan, Ram Prasad

15. Life Cycle Assessment of Lignocellulosic Waste Biorefinery

The twenty-first century is witnessing fossil fuel depletion, increase in the atmospheric concentration of greenhouse gases, industrialization, urbanization and global climate change. There is a growing need to switch over to renewable energy resources and move towards circular bioeconomy. Sustainable bioeconomy has been promoted to replace fossil fuels and to produce bioenergy, chemicals and high value-added products. Biorefineries play a pivotal role in circular bioeconomy. Adoption of biorefineries is a win-win proposition both from the perspective of energy security and waste management. “Biorefining is defined as the sustainable synergetic processing of biomass into a spectrum of marketable food and feed ingredients, products (chemicals, materials) and energy (fuels, power, heat)”. Biorefinery system endeavours to maximize the production of useful products from the biomass. Biorefineries adopt technologies which aim to process the biomass into diverse building blocks. The building blocks are further processed to generate biochemicals and biofuels. The biorefineries are classified based on key features such as (a) feedstocks used in the biorefinery, (b) conversion processes, (c) platform or intermediary products and (d) targeted products. The feedstocks including its characteristics, availability and biodegradability is one of the pertinent factors deciding the sustainability of biorefinery system. The debate between food and fuel has led to the search for second-generation biorefineries, which thrives on non-food biomass. The second-generation biorefineries utilize feedstocks such as residual biomass, lignocellulosic biomass and waste streams. The alternative biomass resources have huge potential for energy generation and can minimize fossil fuel use. Lignocellulose is the most abundant source of unutilised biomass. The positive attributes of lignocellulose biomass are year-round availability of biomass, renewability, sustainability, and amenability to conversion. Nevertheless, lignocellulosic waste biomass requires pretreatment for augmenting the efficiency of the conversion process. Several pretreatment strategies and methods such as physical, chemical and biological methods are adopted to enable lignin deconstruction. The pretreated lignocellulosic biomass through thermochemical conversion (combustion, gasification, hydrothermal processing, liquefaction, pyrolysis) and biochemical conversion are converted into bioenergy, biofuels, speciality chemicals and value-added products. Nevertheless, it is important to assess the impacts of biorefinery on the environment from the perspective of feedstocks, product generation and economic returns. The sustainability of the biorefineries is assessed through the life cycle assessment methodology. Life cycle assessment of biorefineries gains currency on account of (a) technological advancement, (b) bioconversion of diverse feedstocks into value-added products, (c) evaluation of the environmental performance of the biorefineries and (d) validating the sustainable conversion processes. As per ISO 14040, LCA involves four important components, namely goal, scope and functional unit; inventory analysis; impact assessment and interpretation. It has been observed that LCA of lignocellulosic biorefineries is greatly influenced by the methodological attributes, namely the “functional unit”, “system boundaries”, “allocation methods”, LCA approach, etc. LCA studies on lignocellulosic biorefineries reveal that the accuracy and reliability of LCA study are influenced by factors, not limited to data inadequacy, certain assumptions in LCA study and site-specific or local conditions. Though there are challenges to LCA of lignocellulosic waste biorefinery, importance must be placed on the sustainable production of value-added products, efficient utilization of resources, biovalorization and energy efficiency of the biorefinery system. The future research can be directed towards (a) sustainable biorefineries; (b) waste valorization; (c) upscaling the production of value-added products; (d) optimisation of bioconversion processes; (e) sustainable design configuration of the biorefinery; (f) role of biorefineries in the circular economy and (g) contribution of biorefineries in climate change mitigation.
V. Venkatramanan, Shachi Shah, Ram Prasad, Mrinalini Shah
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