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About this book

This book provides a comprehensive review of biosynthetic approaches to the production of industrially important chemicals and the environmental challenges involved. Its 19 chapters discuss different aspects of biosynthetic technology from the perspective of leading experts in the field. It covers various biorefinery approaches, including the use of microbes, metabolically engineered plants, biomass-based and green technology methods. Further, it examines important research in the areas of organic and hazardous waste composting, management and recovery of nutraceuticals from agro-industrial waste, biosynthesis and technological advancements of biosurfactants and waste water bioremediation. This book contributes to the scientific literature on biosynthetic technologies and the related environmental challenges for researchers and academics working in this area around the globe.

Table of Contents

Frontmatter

General

Frontmatter

Chapter 1. Introduction to Biosynthetic Technology and Environmental Challenges

Bio-based processes and products are getting more and more acceptance nowadays mainly because of the environmental friendly process. Many current petroleum-derived products would be replaced by less expensive and better performing products based on renewable materials in near future. This will help for achieving economic and environmental sustainability. Bioeconomy is now emerging as a major industrial breakthrough and new biomass-based products are emerging due to the advancement in technologies. These potential benefits of bio-based products could justify future public policies that encourage a transition to renewable raw materials for production of organic chemicals, fuels and materials. Biosynthetic approaches for production of various industrially important chemicals and products through microbial and plants routes have been discussed in this book. The environmental challenges for its production under biorefinery approach and the various methods for addressing the environmental issues have been discussed in detail.
Sunita J. Varjani, Parameswaran Binod, Sunil Kumar, Sunil K. Khare

Biosynthetic Approaches and Products

Frontmatter

Chapter 2. Management of Agro-industrial Wastes with the Aid of Synthetic Biology

Biomass is the renewable organic material and it can serve as a continuous source of sustainable energy by passing through proper channel. Lignocellulosic biomass is one of the most abundant renewable resources available on earth. Huge amount of lignocellulosic biomass is generated from agricultural and food industries as a waste material, commonly known as agro-industrial waste. It has low value for industries and a big problem as environmental pollutant, therefore its proper management is needed. This agro-industrial waste could be used to generate other valuable products which aid on its value as well as manage agro-waste substances. Thus, several technologies have been applied to recover maximal quantity of valuable products from agro-industrial waste but applications of emerging synthetic biology in production of high-value products seem to be more promising for its management. Synthetic biology is a combination of engineering and biology which is helpful in designing novel biochemical pathways, organisms, or redesign existing, genetic circuits, biological modules, and natural biological systems. Generally, bacteria or yeast biological systems grow easily and are able to produce altered enzymes very efficiently with desired modifications in their genome. These engineered organisms are able to convert agro-industrial waste into valuable products. Nowadays, several valuable products are produced by using synthetic biology approach from industrial waste generated from agro-food industries such as sugarcane bagasse, apple pomace, and citrus peel. Here, we will discuss about agro-industrial waste, biosynthetic tools, and case studies of application of synthetic biology to produce valuable products from agro-industrial waste such as production of prebiotics, nearly calorie-free sugars, and bioactive compounds.
Lokesh Kumar Narnoliya, Jyoti Singh Jadaun, Sudhir Pratap Singh

Chapter 3. Advances and Tools in Engineering Yeast for Pharmaceutical Production

Production of recombinant pharmaceutical protein is a multibillion-dollar industry and plays a crucial role in treatment of many diseases. Among the several potent microbial production systems, yeast offers several advantages in production of pharmaceutically important proteins due to its unicellular nature, easy gene manipulation, cost-effectiveness and fast growth and incorporates post-translational modifications in heterologous proteins. Saccharomyces cerevisiae is the widely used heterologous host for the production of medically important proteins and drugs; however, several non-conventional yeast species including Hansenula polymorpha, Pichia pastoris, and Yarrowia lipolytica are also gaining much attention as alternative heterologous hosts for the industrial production of therapeutic proteins. In this chapter, most recent advances in glycoengineering of yeast for successful therapeutic pharmaceutical production, current progress in humanization of yeast and various interventions in the secretory mechanisms and pathways in yeast for the improvement of the production of pharmaceutical proteins are overviewed. In addition, emerging genetic, omics, systems and synthetic biology tools and other technologies to enhance the efficiency of yeast pharmaceutical proteins are precisely discussed. The use of synthetic biology tools in yeast for the production of pharmaceuticals is clearly entering a new phase right now. Combination of yeast systems biology data with synthetic biology will open new vistas to better production, improved glycosylation and secretory mechanism. The application of currently available synthetic biology tools like CRISPR/Cas9 in yeast pathway engineering is also discussed.
Aravind Madhavan, Raveendran Sindhu, K. B. Arun, Ashok Pandey, Parameswaran Binod

Chapter 4. Plant Biosynthetic Engineering Through Transcription Regulation: An Insight into Molecular Mechanisms During Environmental Stress

Transcription is not only essential for the synthesis of coding and non-coding RNA, but also extremely significant in regulating gene expression with the coordination of several protein complexes in development, differentiation, phenotype, metabolism, exposure to different challenging environmental conditions, and many other cellular pathways. Further extensions of these studies in plant biology will be very helpful in dealing and maintaining a balance between challenging environmental stress, plant resistance, plant productivity, and yield. Different plant secondary metabolites are induced by various developmental, hormonal, and environmental cues and facilitate the plant to fight and cope up with stress conditions. Interestingly, recent advances suggest that the biosynthesis pathway of secondary metabolites is tightly regulated at the transcriptional stages. Keeping in view studying both the molecular mechanisms at a single platform, the aim of this chapter is to understand plant secondary metabolite biosynthetic pathways at the transcriptional level under unfavorable or stressful environmental conditions.
Rakesh Srivastava, Krishan Mohan Rai, Rashmi Srivastava

Chapter 5. Oil Palm Biomass and Its Kinetic Transformation Properties

Malaysia generates millions of tons of oil palm biomass from oil palm mills which need a proper waste utilization application. One of the most commonly method used to utilize the wastes is by using pyrolysis method. This chapter discusses some current applications of biomass pyrolysis. Moreover, kinetic transformation properties of biomass, biomass pyrolysis reaction kinetics, and parameter estimation have also been discussed as the purpose of kinetic modeling is to find a good correlation between reaction rate (k), conversion rate (α), and reaction temperature (T). In order to interpret the biomass pyrolysis behavior, activation energy (E) and pre-factor (A) were needed and calculated based on Arrhenius equation. Last but not least, the recently available kinetic models such as lumped and distributed models are also listed.
Muhammad Fakhrul Syukri Abd Aziz, Zainul Akmar Zakaria

Chapter 6. Selection and Utilization of Agro-industrial Waste for Biosynthesis and Hyper-Production of Pullulan: A Review

The emergence of modern microbial technology and product biotechnology had significantly made over the way, scientists and researchers view differently the microbes and the product they biosynthesize. Pullulan is one of the most potent bio-compatible polymers which is basically synthesized by the Aureobasidium pullulans. This microbial pullulan acts as the promising biomaterial that is currently used for packaging of readily oxidized food materials, controlled drug delivery, tissue engineering and can also function as artificial molecular chaperones. Commercial pullulan is expensive. It was also estimated that the cost of pullulan is three times higher than the other polysaccharides. However, the cost of the raw materials required for pullulan production accounts for 30% of the total production costs. Therefore, it is essential to search out the cheapest substrate for the production of pullulan. From 1999 till date, different groups of researcher had found and reported various carbon source and nitrogen source from the waste products to be utilized for pullulan production. This review attempts to critically appraise the current literature on ‘pullulan’ considering its microbial sources and utilization of various agro-industrial wastes for pullulan production.
Bishwambhar Mishra, Deveeka Zamare, Akula Manikanta

Chapter 7. Production, Characterization, and Applications of Microbial Poly-γ-Glutamic Acid

Poly γ-glutamic acid is a promising biodegradable polymer from bacterial sources with intense applications in the field of medicine, wastewater treatment, food and cosmetics, etc. In the production process, the yield of polygamma glutamic acid varies with the various parameters like nutrient requirements, culture conditions, and the bacterial strains used for the production and the mode of fermentation. Industrial scale production of this high value-added product is not still feasible because of its high production cost. Due to its commercial interest, the cost-effective process for production, efficient recovery, and purification are the current area of interest. Here, main focus is on the production, purification, characterization, and applications of PGA from bacterial sources.
Alphonsa Jose Anju, Raveendran Sindhu, Binod Parameswaran, Ashok Pandey

Chapter 8. Bioprocesses for the Production of 2,5-Furandicarboxylic Acid

Recently, major industries focus on the chemical processes for the production of “green” alternative substance 2,5-furandicarboxylic acid (FDCA) for polymers, from glucose, fructose, and even from biomass through HMF as intermediate, although biological processes have greater significance nowadays as a less toxic method for the production of FDCA. Until now, only laboratory-scale production has been reported as biological approaches like whole cell using microorganisms and enzymatic approaches from many countries. According to the reports, for microbial production, a genetically engineered strain P. putida S12 with co-expressed genes showed the highest production of 150 g/L FDCA from HMF. For enzyme-assisted biocatalysis galactose oxidase M3–5, periplasmic aldehyde oxidase (PaoABC) and a catalase have been used as one-pot experiment for sequential oxidations higher substrate concentration HMF (100 mM) and obtained 74% of FDCA production. Acid precipitation (pH 0.5–3), cooling, and centrifugation followed by solvent extraction is normally used for the purification of FDCA from microbial broth and enzyme reaction mixture. From enzyme reaction media, a maximum of 15 mg has been obtained in pure form from a 40 mg (FDCA) production media. Further experiments are needed for the efficient biological production and purification of FDCA for industries from the current laboratory scale.
R. O. Rajesh, Ashok Pandey, Parameswaran Binod

Chapter 9. Biosynthesis of 1,3-Propanediol: Genetics and Applications

Increased demand for renewable fuels and remarkable growth of biodiesel industry resulted in the accumulation of huge quantities of crude glycerol as the by-product. In the context of utilizing this by-product as the raw material, various fine and bulk chemicals were synthesized, among them 1,3-propanediol gained more importance due to its flexible properties as a monomer. Understanding the microbial physiology and genetics with integrated knowledge on molecular tools and techniques helps in developing engineered biocatalysts for the synthesis of 1,3-propanediol in higher titers and productivity. The microbial production of 1,3-propanediol was reviewed in brief regarding, the chemical process and its limitations, glycerol dissimilation, genetics of dha regulon in various microorganisms, metabolic engineering approaches to improve glycerol utilization for 1,3-PDO production, new strategies in modes of fermentation along with the future prospective was outlined.
Narisetty Vivek, Parameswaran Binod

Chapter 10. Biosynthesis and Technological Advancements of Biosurfactants

The growing industrial development and concomitant efforts to protect mother Earth from alleviating pollution levels has greatly demanded the use and disposal of milder chemicals and xenobiotics. Of the widely used xenobiotics, surfactants have an increasing market demand due to its prevalent role in pharmaceutical preparations, food industry as well as almost all foaming products. The use of biosurfactants in place of chemical surfactants has gained momentum owing to the low toxicity, higher biodegradability and better environmental compatibility of biosurfactants. The current review outlays the various biosurfactants produced and their significance in various industries. An outline of the various biosynthetic pathways, challenges and advancements in the synthesis of the two mostly used biologically synthesised biosurfactants—rhamnolipids and sophorolipids has been discussed.
Sharrel Rebello, Embalil Mathachan Aneesh, Raveendran Sindhu, Parameswaran Binod, Ashok Pandey

Chapter 11. Recovery of Nutraceuticals from Agri-Food Industry Waste by Lactic Acid Fermentation

The enormous amount of by-products produced in the food and agricultural sector and the current attention towards sustainability is attracting researchers to look into possibilities of its utilization in the recovery of nutraceuticals. Nutraceuticals are food or food products that confer health and medical benefits, and are instrumental in the prevention and treatment of diseases. The agri-food industry by-products are an excellent source of proteins, lipids, fibre and other bioactive compounds. Among the different methods used for the extraction of these bioactive compounds (nutraceuticals), fermentation by lactic acid bacteria is one of the economical and eco-friendly approaches. During fermentation, chemical changes induced in the organic substrate by the action of microorganisms aids in the formation of bioactive compounds, either by a process of hydrolysis of large polymers to simple molecules, or transformation of substrates. This book chapter discusses the role of lactic acid fermentation in transformation/hydrolysis of by-products for the efficient recovery of nutraceuticals. The bioprocess of recovery of nutraceuticals from waste by lactic acid fermentation with better efficiency adds value to the food waste, reduces environmental pollution and has a positive impact on the economy.
Lyned D. Lasrado, Amit Kumar Rai

Chapter 12. Manno-oligosaccharides as Prebiotic-Valued Products from Agro-waste

Agriculture is the backbone of Indian economy, is carried out for primary products where a significant amount of agro-waste is produced. About 72% of fruits and vegetable production in India goes waste, due to their processing variability which meets about 1.4% of the total global trade. Therefore, the agro-waste utilization for human benefit is the major concern for environmental sustainability. Such waste can be effectively used for the production of useful compounds for animals and human beings. Lignocellulosic agro-waste has been explored for the production of energy as biofuels. Such biomass can also be considered to be useful for the production of prebiotic oligosaccharides. Different agro-wastes such as copra meal, potato peel, rice straw, wheat straw, corncob, palm kernel meal, etc., can be used for the production of different oligosaccharides. Oligosaccharides are short chains of monosaccharides of the size ranging from two to ten units of monosaccharides or simple sugars. The oligosaccharides are highly stable and are used as dietary supplement possessing prebiotic, antioxidant activity and potential immune-modulating properties. Manno-oligosaccharides can be produced from pretreated agro-waste by hydrolysis with endo-β-(1 → 4)-mannanase. MOSs has significant stability against α-amylase, intestinal juice, and simulated gastric juice which is an essential parameter for oligosaccharides to serve as a prebiotic. Nevertheless, MOSs also supports higher growth rate of probiotic bacteria Bifidobacterium infantis and Lactobacillus acidophilus as compared to commercial prebiotic. In addition to prebiotic properties, MOS significantly reduces the growth of colon cancer cells that depicts their antagonistic properties without any cytotoxic effect against the normal cell culture. This chapter will describe the roles of manno-oligosaccharides recovered from agro-waste which have applications as prebiotics, acting antagonistic agent against cancer cells and as anti-allergic agents.
Shweta Singh, Arabinda Ghosh, Arun Goyal

Chapter 13. Computational Modelling and Prediction of Microalgae Growth Focused Towards Improved Lipid Production

In response to compelling demands worldwide for sources of renewable and eco-friendly energy feedstock, research and development in microalgae as a sustainable alternative has garnered interest. In order to make microalgae-derived fuel more competitive than fossil fuels in terms of cost, bottlenecks like scalability, better biomass production and enhanced lipid production without nutritional stress need to be resolved. In this chapter, the various computational modelling methods applied to microalgae growth in various environmental conditions have been reviewed. The possibility and potential of employing these models for better lipid production have also been highlighted, as better predictability of models can lead to better transgenic algal platform. Moreover, the upcoming models integrating omics data with flux analysis have also been discussed that has resulted in updated simulation due to the incorporation of data about novel genes. Lastly, the need for close collaboration between biochemical engineers, molecular biologists and modellers have been emphasised to validate the models on natural environment apart from laboratory conditions.
Avik Banerjee, Niwas Kumar, Sunita J. Varjani, Chandan Guria, Rajib Bandopadhyay, Pratyoosh Shukla, Chiranjib Banerjee

Chapter 14. Perennial Energy Crops on Drained Peatlands in Finland

Finland has a large area under peatlands (more than 10 M ha). Under pristine conditions, peatlands are a sink for atmospheric CO2 and a source of methane to the atmosphere. Since the 1950s, peatlands in Finland have been drained for forestry, agriculture, and peat extraction for energy. Once drained, peatlands transform into large sources of CO2 to the atmosphere and weak sinks for methane. Finding a suitable after-use option for drained peatlands is complicated by the specific nature of the drained peatland type. As an after-use option on a cutover peatland, the cultivation of a perennial bioenergy crop on a drained peatland in eastern Finland was explored during 2004–2011. The long-term measurements of greenhouse gas exchange from this study site showed that the benefits from bioenergy crop cultivation vary strongly depending on the climatic conditions during the crop cultivation phase.
Narasinha J. Shurpali

Environmental Assessment and Waste Management

Frontmatter

Chapter 15. Bioenergy Conversion from Aquatic Weed Water Hyacinth into Agronomically Valuable Vermicompost

Increasing amount of waste due to urbanization, lifestyle and shift of huge masses from rural to urban largely contributes to the need for waste management. This developed a need of categorizing the waste into municipal waste, industrial waste, agricultural waste, hospital waste, etc., which will make it easy for the proper disposal, reuse and recycling of waste so determined effort should be taken for the management of waste. For this purpose, proper canalization of segregation, distribution, disposal, recycling, reuse of waste without deteriorating the environment is a matter of great concern. To succeed in these all the stakeholders like users creating waste, environmentalist, scientist, municipal stakeholders and doctors should take an initiative and need to participate in the same. For proper management of solid waste, continuous efforts have been made by recycling and reusing the plant weed. Vermicomposting is the biocomposting process of organic waste by earthworms and bacterial action directing the stabilization of organic matter. The final product produced in this process is known as vermicompost and it assists in the enrichment of soil as well as useful for sustainable agriculture. This technology is a boon for recycling of the solid waste generated from various sources including aquatic weeds. The prime objective of the present investigation is to convert waste into wealth. Its application to the agricultural field is also retrieving the waste garbage into gold. The present investigation is mainly focused on vermicompost production from water hyacinth (Eichhornia crassipes) collected from local perennial Sambhaji tank from Solapur and its application to a commercial crop groundnut (Arachis hypogaea) for total yield and biomass production. The significant output of the commercial crop groundnut displays the extended use of vermicompost in agriculture, providing an insight and approach for organic farming in future. Our results suggest that the vermibiotechnology is an eco-friendly and economically feasible technology and it is also helpful for converting waste into bioenergy.
Ankaram Snehalata, Kothur R. Rao

Chapter 16. Mitigation of Global Warming Potential for Cleaner Composting

With the rapidly growing human population, urbanization, and the uplifting living standards in all over the world, huge amount of solid waste was generated. It is expected that the entire amount of word solid waste production would climb from more ~3.5 million to >6 million tons/day from 2010 to 2025, and the rate would continue to increase and reach a peak to over 11 million tons/day about by the year 2100. Thus, how to manage those increasing solid waste generation was becoming a great issue for the sustainable civil infrastructure. Organic waste, which includes food scraps, yard wastes, agricultural wastes, and process residues, took the largest proportion of the overall generated solid waste by 46%. But ~90% of the solid waste is directly disposed into the landfill that can produce a considerable proportion of flue gases (generally the CH4 and N2O gases) due to the anaerobic mineralization of bio-available organic matter. Composting is an eco-friendly alternative “Old & Gold” technology to landfilling for the management of organic waste. Its principal interest lies in its potential to recycle the organic nutrients through compost application. The life cycle measurement has been extensively used as a mean of evaluation for impact assessment, such as overall warming potential, along with different waste management technologies. The typical methods assumed for composting comprise transportation of organic waste, viable machinery, greenhouse gases (GHGs) emissions during the curing phase, as well as the end-product application. There is a divergence in the adopted operational methodology to determine its environmental effect. This chapter deliberates on the variations of life cycle computation of solid waste management that involved different global warming potentials of composting. It is also based on the GHGs mitigation approaches to minimize the global warming impact by aerobic composting. The element of the study is to examine the difference in the inventory investigation for composting, and its fundamental mechanism and the significant inventory for an additional assessment. This study establishes that the GHGs emissions which emit directly during the composting process supply additional global warming prospective rather than further emissions. The bulking agent is used for the mitigation of overall warming potential. The measurement of the composting and its impact on global warming prospective is widely dependent on many defined efficient components. The environmental impact should be examined based on the operational approach and the input feedstock to generate a basis with minimized discrepancies among studies. Consecutive exercise is compulsory to evaluate the everlasting assistance of composting on environment, health, and soil properties to further identify its effect as a cleaner technology. Demonstration of mitigation method of field-research is an essential step toward the acquiescence of organic farming with global GHGs emissions moderation object through composting. Therefore, in this chapter, provides a detailed account of the technological advancement and composting approaches in global prospects for mitigation of GHGs emission, environmental safety, and human health protection.
Mukesh Kumar Awasthi, Surendra Sarsaiya, Quan Wang, Meijing Wang, Hongyu Chen, Xiuna Ren, Sunil Kumar, Zengqiang Zhang

Chapter 17. Recent Advances in Composting of Organic and Hazardous Waste: A Road Map to Safer Environment

With the rapid development of economy and agriculture, continues to be the fast increase of organic and hazardous wastes such as animal manure, sewage sludge, green waste, antibiotics residue, municipal solid waste, and agricultural waste. These wastes contain lots of organic matter and nutrients, and also contain various kinds of toxic materials or elements (e.g., heavy metals, pathogens, antibiotics and antibiotics gens). The improper disposal of these wastes would result in environmental pollution and potential risk of human health. Composting technology is a kind of biological waste treatments, which has been widely accepted as an alternative method to recycle the organic matter and produce a stable and sanitary soil fertilizer or amendment. Furthermore, many researchers have elucidated the major factors such as temperature, pH, C/N ratio, moisture content, and particle size that are relevant in the monitoring of the composting process. However, the traditional composting still has some drawbacks such as nitrogen loss, leachate generation, odor problem, greenhouse gases (CH4 and N2O) emission, heavy metals (HMs) mobility, antibiotic residue, and antibiotic gens diffusion. During the composting process, 9.6–46% initial total nitrogen (N) is lost due to the volatilization of NH3, which not only decreases the compost quality, but also worsens the air pollution. Meanwhile, the greenhouse gases (CH4 and N2O) emission leads to environmental pollution. In addition, the high bioavailability of HMs in compost and the residual of antibiotic and antibiotic gens would also limit the development of composting technology and the land use of compost as well as cause hazard for ecosystem. In order to promote the composting progress and reduce the adverse effect during composting, many viable practical approaches have been applied adjusting the physicochemical parameters (e.g., moisture, C/N ratio, aeration rate and pH), using the different kinds of bulking agents, and adding the chemical agents, mineral additives, and microbial agent. This chapter discusses the benefit and challenge of composting of organic and hazardous waste. It will also discuss the current method to promote the compost quality and reduce the environmental risk.
Quan Wang, Mukesh Kumar Awasthi, Xiuna Ren, Junchao Zhao, Meijing Wang, Hongyu Chen, Zengqiang Zhang

Chapter 18. Integration of Biomarker Approach in Pollution Monitoring Programme of Aquatic Ecosystem

Water bodies are subjected to a considerable pressure from sewage and industrial wastes. Monitoring methods adopted so far have helped in the assessment level of contaminants in water but not the interaction of these pollutants with living organisms. Water quality testing programmes use two traditional methods for water quality assessment that includes physico-chemical parameters and bio-monitoring. Looking at the limitations of these two traditional methods, a new method known as ‘biomarkers of pollution’ should be adopted. Evaluating various biomarkers in sentinel species can be of great help in environmental monitoring programme as they forecast various risks and hazards associated with the habitats of aquatic animals. Several countries have adopted Biomarkers in their environmental monitoring programmes; however, to make it a routine and well-recognized tool in the water quality monitoring programme, efforts are still required from scientific communities. The major advantage of Biomarkers is that bioavailability or potential exposure to toxicants can be demonstrated which is not possible in chemical analysis. Persistent organic pollutants (POPs) are chemical substances that do not degrade easily and persist in the environment and detecting some classes of POPs, for example organochlorine compounds, are very difficult as the limits of detection are very low. With the advancement of analytical methods, these chemicals can be now detected in every environmental matrices but changes caused physiologically in living organisms remains unknown. This limitation can be overcome with the help of biomarkers which can detect whether organisms are exposed meaningfully and the physiology is altered in comparison to normal. Whenever any pollutants enter the biological system, it brings molecular changes and the response time of molecular changes are faster than it appears at community level. This leads the scientific communities to start some research work in this area in order to develop some early warning signal or biomarkers. Measurement of molecular changes at the level of body fluids, cells or tissues reflecting an alteration in normal functioning/magnitude due to the presence of toxicants forms the basis of selection of particular parameter as a biomarker. This chapter presents the importance of various core biomarkers used as diagnostic and prognostic tools to monitor the water quality assessing the risks associated with the health of aquatic biota. This is high time to focus on the biological responses which are more relevant to predict the health status of any aquatic ecosystem before occurrence of any catastrophic events which are unmanageable.
Kanchan Kumari, Ankur Khare

Chapter 19. Bioremediation by Microalgae: Current and Emerging Trends for Effluents Treatments for Value Addition of Waste Streams

The development of anthropogenic activities has lead to an excessive disposal of wastes into natural waterbodies, thus affecting the quality of water and polluting the entire environment due to the hazardous chemicals and other nutrients present in the waste, thereby it has a negative impact on the aquatic ecosystems. To avoid these harmful impacts associated with the discharge of wastes into waterbodies, effective remediation processes are required to reduce nutrients like nitrogen, phosphorus, other organic chemicals and heavy metals concentrations in discharged effluents. Current technologies applied for nutrients removal tend to be complex, energy demanding and costly process. Therefore, cultivation of microalgae has appeared as an emerging alternative approach for removing pollutants and heavy metals present in the waterbodies. Biomass production in the alga depends on rapid utilization of the organic content and other nutrients present in the effluent and can be considered as an attractive and eco-friendly means for treating waste streams, other than removing the pollution load, algal cultivation adds value to the process by production of commercially valuable products such as fuels and various chemicals from biomass. This chapter addresses the recent developments and perspectives in bioremediation of waste streams by algae for removal of various pollutants for value addition of waste.
Sabeela Beevi Ummalyma, Ashok Pandey, Rajeev K. Sukumaran, Dinabandhu Sahoo

Chapter 20. Environmental Assessment of Biorefineries

The development of the biorefinery concept is based on the techno-economic feasibility of the proposed process considering raw materials, process options, mass and energy integration, market constraints, etc. Nevertheless, along with all these considerations, the environmental assessment must be taken into account at the same time, and concepts like sustainability, land uses, environmental impacts, and other related issues must be included in the biorefinery design since the first moment. This work summarizes the main methodologies and aspects concerning the environmental assessment of biorefineries. Different case studies covering a wide range of raw materials and products are also presented.
Juan Miguel Romero-García, Christian David Botero Gutiérrez, Juan Camilo Solarte Toro, Carlos Ariel Cardona Alzate, Eulogio Castro
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