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In this study, fatty acid feedstock preparation and lactic acid production as integrated processes in mixed restaurant food and bakery waste treatment were investigated. The treatment included the hydrolysis of waste using extracellular fungal enzymes in submerged fermentation. By hydrolysis, 0.27 g glucose, 4.7 mg free amino nitrogen (FAN) and 1.9 mg phosphate were recovered per gram dry waste material. After hydrolysis, a lipid-rich solid fraction, to be used as a source of fatty acids, remained. The nutrient-rich hydrolysate was used as medium in fed-batch cultures of the heterotrophic microalga Chlorella pyrenoidosa, which grew well at a rate of 1.4 day− 1. In order to establish a cost- and water-efficient process, hydrolysis and algae cultivation were performed in recycled culture supernatant without any negative impacts on the fungal hydrolysis and growth of C. pyrenoidosa. The extraction of lipids from algal biomass and lipid-rich solids resulted in a saturated and unsaturated fatty acid-rich feedstock. Defatted waste derived solids and algal biomass were further tested successfully as nitrogen sources in lactic acid production using Bacillus coagulans. The outcomes of this study contribute to the establishment of a ‘green society’ by utilization of waste material in the production of chemicals, materials and fuels.

The potential of lipids derived from food-waste and algal biomass (produced from food-waste hydrolysate) for the formation of plasticizers and surfactants is investigated herein. Plasticizers were formed by epoxidation of double bonds of methylated unsaturated fatty acids with in situ generated peroxoformic acid. Assuming that all unsaturated fatty acids are convertible, 0.35 and 0.40 g of plasticizer can be obtained from 1 g of crude algae- or food-waste-derived lipids, respectively. Surfactants were formed by transesterification of saturated and epoxidized fatty acid methyl esters (FAMEs) with polyglycerol. The addition of polyglycerol would result in a complete conversion of saturated and epoxidized FAMEs to fatty acid polyglycerol esters. This study successfully demonstrates the conversion of food-waste into value-added chemicals using simple and conventional chemical reactions.

Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) are a large class of biopolymers that have attracted extensive attention as renewable and biodegradable bio-plastics. They are naturally synthesized via fatty acid de novo biosynthesis pathway or β-oxidation pathway from Pseudomonads. The unconventional yeast Yarrowia lipolytica has excellent lipid/fatty acid catabolism and anabolism capacity depending of the mode of culture. Nevertheless, it cannot naturally synthesize PHA, as it does not express an intrinsic PHA synthase. Here, we constructed a genetically modified strain of Y. lipolytica by heterologously expressing PhaC1 gene from P. aeruginosa PAO1 with a PTS1 peroxisomal signal. When in single copy, the codon optimized PhaC1 allowed the synthesis of 0.205 % DCW of PHA after 72 h cultivation in YNBD medium containing 0.1 % oleic acid. By using a multi-copy integration strategy, PHA content increased to 2.84 % DCW when the concentration of oleic acid in YNBD was 1.0 %. Furthermore, when the recombinant yeast was grown in the medium containing triolein, PHA accumulated up to 5.0 % DCW with as high as 21.9 g/L DCW, which represented 1.11 g/L in the culture. Our results demonstrated the potential use of Y. lipolytica as a promising microbial cell factory for PHA production using food waste, which contains lipids and other essential nutrients.

Depletion of fossil fuels and environmental problems are encouraging research on alternative fuels of renewable sources. Biodiesel is a promising alternative fuel to be used as a substitute to the petroleum based diesel fuels. However, the cost of biodiesel production is high and is attributed mainly to the feedstock used which leads to the investigation of low cost feedstocks that are economically feasible. In this paper, we report on the utilization of lipid obtained from food waste as a low-cost feedstock for biodiesel production. Lipid from food waste was transesterified with methanol using base and lipase as catalysts. The maximum biodiesel yield was 100% for the base (KOH) catalyzed transesterification at 1:10 M ratio of lipid to methanol in 2 h at 60 °C. Novozyme-435 yielded a 90% FAME conversion at 40 °C and 1:5 lipid to methanol molar ratio in 24 h. Lipid obtained from fungal hydrolysis of food waste is found to be a suitable feedstock for biodiesel production.

Demand for biofuels is rapidly growing worldwide as petroleum based fuels are finite reserves. In this context, biodiesel and bioethanol are popular biofuels that are commercially available in various countries. Biofuels can be prepared from edible biomass. However, this is already generating food versus fuel debate among the members of civil societies. Therefore, there are needs to synthesize biofuels from nonedible waste materials. Food wastes can be utilized as resources for the production of biodiesel and bioethanol since they contain significant amount of lipids and carbohydrates. In future, industrial production of biodiesel and bioethanol from food waste can contribute to resolve the waste disposal, energy scarcity and energy security problems.

Due to serious public health threats resulting from mercury pollution and its rapid distribution in our food chain through the contamination of water bodies, stringent regulations have been enacted on mercury-laden wastewater discharge. Activated carbons have been widely used in the removal of mercuric ions from aqueous effluents. The surface and textural characteristics of activated carbons are the two decisive factors in their efficiency in mercury removal from wastewater. Herein, the structural properties and binding affinity of mercuric ions from effluents have been presented. Also, specific attention has been directed to the effect of sulfur-containing functional moieties on enhancing the mercury adsorption. It has been demonstrated that surface area, pore size, pore size distribution and surface functional groups should collectively be taken into consideration in designing the optimal mercury removal process. Moreover, the mercury adsorption mechanism has been addressed using equilibrium adsorption isotherm, thermodynamic and kinetic studies. Further recommendations have been proposed with the aim of increasing the mercury removal efficiency using carbon activation processes with lower energy input, while achieving similar or even higher efficiencies.

With the increasing awareness and concern about the dependency on fossil resources and the depletion of crude oil reserves, experts from industrial biotechnology, renewable resources, green chemistry, and biorefineries are stimulating the transition from the fossil-based to the bio-based economy. This text confronts scientific and economic challenges and strategies for making this crucial transition. Renewable Resources for Biorefineries is the work of a strongly interdisciplinary authorship, offering perspectives from biology, chemistry, biochemical engineering, materials science, and industry. This unique approach provides an opportunity for a much broader coverage of biomass and valorisation than has been attempted in previous titles. This book also represents the fundamentally important technical and policy aspects of a bio-based economy, to ground this important science in a realistic and viable economic framework. Chapters in this book cover a diverse range of topics, including: advanced generation bioenergy sectors; biobased polymers and materials; chemical platform molecules; industrial crops and biorefineries; financing and policy for change; and valorisation of biomass waste streams. This is an ideal book for upper level undergraduate and postgraduate students taking modules on Renewable resources, green chemistry, sustainable development, environmental science, agricultural science and environmental technology. It will also benefit industry professionals and product developers who are looking to improve economic and environmental ways to utilise renewable resources in current and future biorefineries.

In recent years, there have been increased concerns about the disposal of food waste. The amount of food waste generated globally is staggering, with about 1.3 billion tonnes per year and the figures are rising. In Hong Kong, about 3000 tonnes of food waste have been generated every day over the past 10 years with a significant increasing trend. With the waste-to-landfill approach, huge amounts of food waste is being dumped to landfills, making food waste a significant component of municipal solid waste (MSW) and losing a potentially valuable food source or regenerated resource (e.g. energy recovery, composting and animal feed). In addition, many other environmental problems are associated with the disposal of food waste to landfill. In this chapter, attempts are made to review the current food waste disposal system in Hong Kong and some food waste valorization technologies, which have been practiced in other counties or regions, along with their advantages and limitations so as to improve the present food waste disposal system from a technological perspective. Our recommendations includes a comprehensive system to facilitate different approaches to recycle such important protein and carbon sources into valuable products from biofuels to animal feeds.

The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.

Section I Fundamentals of Engineering Analysis and Design of Bioenergy Production Systems Genetic Engineering of Bioenergy Crops toward High Biofuel Production Guosheng Xie and Liangcai Peng Novel Cropping Technologies and Management Applied to Energy Crops Lorenzo Barbanti Mathematical Modeling in Biomass and Bioenergy Systems Lijun Wang, Samuel Asomaning Agyemang and Abolghasem Shahbazi Life-Cycle Assessment of Bioenergy Systems Reinout Heijungs and Edi Iswanto Wiloso Sustainability of Bioenergy Systems Lucas Reijnders Section II Sustainable Biomass Production and Supply Logistics Production and Supply Logistics of Microalgae as an Energy Feedstock Helena M. Amaro, F. Xavier Malcata, and I. Sousa-Pinto Production and Supply Logistics of Switchgrass as an Energy Feedstock Marty R. Schmer and Igathinathane Cannayen Production and Supply Logistics of Sweet Sorghum as an Energy Feedstock Sergio O. Serna-Saldivar and William L. Rooney Production and Supply Logistics of Sugarcane as an Energy Feedstock Jose Goldemberg, Suani T. Coelho, Plinio M. Nastari, and Patricia Guardabassi Crop Residues as an Energy Feedstock: Availability and Sustainability Dong Jiang, Dafang Zhuang, and Yaohuan Huang Woody Biomass as an Energy Feedstock: Availability and Sustainability Birger Solberg Animal Wastes as an Energy Feedstock: Availability and Sustainability Hui Wang and Lijun Wang Municipal Solid-Waste Management Strategies for Renewable Energy Options Richa Kothari, Virendra Kumar, N.L. Pawar, and V.V. Tyagi Food Processing Wastes as an Energy Feedstock: Availability and Sustainability Lijun Wang Section III Sustainable Bioenergy Processing Fermentation in Transportation Alcohols Jonathan Moncada, Luis A. Toro, and Carlos A. Cardona Biodiesel Production from Waste Feedstock Dennis Y.C. Leung and Xuan Wu Biomass Gasification and Syngas Utilization Ajay Kumar, Ashokkumar Sharma, and Pushpak Bhandari Biomass Pyrolysis and Bio-oil Utilization Lijun Wang and Dan Cheng Hydrothermal Liquefaction of Biomass Nor Aishah Saidina Amin, Javaid Akhtar, and Selhan Karagoz Anaerobic Digestion of Organic Wastes Bo Zhang and Lijun Wang Combined Heat and Power Generation from Biomass Hao Liu and Rabah Boukhanouf Section IV Sustainable Biorefinery Systems Biorefinery Principles, Analysis, and Design Zheng Liu and Mario Richard Eden Lignocellulosic Feedstock Biorefinery Karin Arens and Shijie Liu Whole-Crop Biorefinery Apostolis A. Koutinas, Carol Lin, Chenyu Du, and Colin Webb Green Biorefinery H.S. Shekhar Sharma and Michael Mandl

Potential of fungal hydrolysis in submerged fermentation by Aspergillus awamori and Aspergillus oryzae as a food waste treatment process and for preparation of fermentation feedstock has been investigated. By fungal hydrolysis, 80–90% of the initial amount of waste was reduced and degraded within 36–48 h into glucose, free amino nitrogen (FAN) and phosphate. Experiments revealed that 80–90% of starch can be converted into glucose and highest concentration of FAN obtained, when solid mashes of A . awamori and A . oryzae are successively added to fermentations at an interval of 24 h. A maximal solid-to-liquid ratio of 43.2% (w/v) of food waste has been tested without a negative impact on releases of glucose, FAN and phosphate, and final concentrations of 143 g L −1 , 1.8 g L −1 and 1.6 g L −1 were obtained in the hydrolysate, respectively. Additionally, fungal hydrolysis as an alternative to conventional treatments for utilization of food waste is discussed.

Coupling reactions have been part of several extensive studies in order to develop innovative and greener protocols that can generate a wide range of compounds with applications in pharmaceuticals, agrochemicals and biologically active compounds. Metal-free couplings are an important and increasingly trendy field that has attracted a significant deal of interest in recent years, generating a lot of controversy on the issue of whether metal free is really free. Aside from focusing on such a controversial topic itself, this contribution aims to provide a brief introduction on coupling chemistry to point out the transition of this technology from metal-catalyzed to metal-free. This is followed by a range of key selected synthetically useful metal-free processes and a brief commentary on the current debate of whether metal-free reactions are really metal-free and the required experiments for a full understanding of a metal-free coupling process.

The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.

Restructuring conventional cereal-based processes is essential in order to create viable biorefineries for the production of fuels, chemicals and materials. Advanced biorefinery schemes should exploit the full potential of cereal grains by exploiting every component and residue to produce a wide spectrum of commodity and speciality products. This chapter presents generic biorefinery approaches that utilize the wheat grain for the production of bioethanol, polyhydroxybutyrate, succinic acid and various added-value products (e.g., arabinoxylans). Cereal-based food by-product or waste streams generated from primary processing of cereals, households, restaurants and catering services could be used for the development of second-generation biorefineries.

In this study,Halomonas boliviensiswas cultivated on bakery waste hydrolysate and seawater in batch and fed-batch cultures for polyhydroxybutyrate (PHB) production. Results demonstrated that bakery waste hydrolysate and seawater could be efficiently utilized byHalomonas boliviensiswhile PHB contents between 10 and 30% (w/w) were obtained. Furthermore, three methods for bakery waste hydrolysis were investigated for feedstock preparation. These include: (1) use of crude enzyme extracts fromAspergillus awamori, (2)Aspergillus awamorisolid mashes, and (3) commercial glucoamylase. In the first method, the resultant free amino nitrogen (FAN) concentration in hydrolysates was 150 and 250 mg L−1after 20 hours at enzyme-to-solid ratios of 6.9 and 13.1 U g−1, respectively. In both cases, the final glucose concentration was around 130–150 g L−1. In the second method, the resultant FAN and glucose concentrations were 250 mg L−1and 150 g L−1, respectively. In the third method, highest glucose and lowest FAN concentrations of 170–200 g L−1and 100 mg L−1, respectively, were obtained in hydrolysates after only 5 hours. The present work has generated promising information contributing to the sustainable production of bioplastic using bakery waste hydrolysate.

Glucose, free amino nitrogen (FAN), and phosphate were recovered from food waste by fungal hydrolysis using Aspergillus awamori and Aspergillus oryzae . Using 100 g food waste (dry weight), 31.9 g glucose, 0.28 g FAN, and 0.38 g phosphate were recovered after 24 h of hydrolysis. The pure hydrolysate has then been used as culture medium and nutrient source for the two heterotrophic microalgae Schizochytrium mangrovei and Chlorella pyrenoidosa , S. mangrovei and C. pyrenoidosa grew well on the complex food waste hydrolysate by utilizing the nutrients recovered. At the end of fermentation 10–20 g biomass were produced rich in carbohydrates, lipids, proteins, and saturated and polyunsaturated fatty acids. Results of this study revealed the potential of food waste hydrolysate as culture medium and nutrient source in microalgae cultivation.

The mechanical properties of biopolymers, such as polyesters, polysaccharides and proteins, can pose issues that need to be overcome. These issues are stiffness, brittleness, poor elongation to break and relatively high cost. Whereas, natural rubber exhibits a unique combination of toughness, flexibility, biocompatibility and biodegradability that together with its low cost makes it an ideal candidate to overcome the drawbacks of the above-mentioned biopolymers. However biopolymers/natural rubber blends normally do not lead to miscible systems, alternative approaches have been used to establish some compatibility between them, in an attempt to create ‘new’ materials with advanced functionalities. For instance, in situ reactive blend is sometimes a good alternative to improve compatibility or the use of a third polymer as a compatibilizer. It is also possible to use both aforementioned alternatives, i.e. combination of reactive blending with compatibilizers, the choice being guided by the system and the biopolymer used. This chapter is designed to provide an overview of the state of the art of blends between natural rubber and biopolymers. The preparation or processing of the blends and the structure–property relationship are emphasized, as well as their industrial applications.

Polycondensation and ring-opening polymerization are two important polymer synthesis methods. Poly(lactic acid), the most typical biodegradable polymer, has been researched extensively from 1900s. It is of significant importance to have an up-to-date review on the recent improvement in techniques for biodegradable polymers. This review takes poly(lactic acid) as the example to present newly developed polymer synthesis techniques on polycondensation and ring-opening polymerization reported in the recent decade (2005-2015) on the basis of industrial technique modifications and advanced laboratory research. Different polymerization methods, including various solvents, heating programs, reaction apparatus and catalyst systems, are summarized and compared with the current industrial production situation. Newly developed modification techniques for polymer properties improvement are also discussed based on the case of poly(lactic acid).

Gold colloidal nanomaterials have been synthesized using different methodologies and characterized by a novel nanoparticle tracking analysis (NTA) technique as compared to conventional Transmission Electron Microscopy (TEM) characterisation. Results prove that NTA is a highly useful, simple, efficient and rapid characterisation tool for Au nanoparticles and nanorods, providing a highly reliable and fast alternative to traditional characterisation techniques. This approach provides a very simple way of studying nanoparticles and some of their properties. Studies on the stabilizing/capping effect of a variety of biomass-derived compounds also show different possibilities for the use of polysaccharide to stabilise colloidal Au solutions.

In this paper, bakery waste, including cakes and pastries from Starbucks Hong Kong, was evaluated for the potential of succinic acid (SA) production. Through simultaneous hydrolysis and fungal autolysis, both cake and pastry hydrolysates were found to be rich in glucose (35.6 and 54.2 g L−1) and free amino nitrogen (685.5 and 758.5 g L−1), whereas the protein hydrolysis yields were 23.2 and 22.5%, respectively. These cake and pastry hydrolysates, together with magnesium carbonate (10 g L−1) were subsequently used as feedstock in Actinobacillus succinogenes fermentation, and the resultant SA concentrations were 24.8 and 31.7 g L−1, respectively. A cation-exchange resin-based process (via vacuum distillation and crystallisation) was subsequently used to recover the SA crystals from fermentation broth, and a high SA crystal purity (96–97.7%) was obtained. Results of the present work successfully demonstrated the novel use of bakery waste as the generic feedstock for the sustainable production of SA as a platform chemical in food waste biorefinery.

Increasing demand for fuels and chemicals, driven by factors including over-population, the threat of global warming and the scarcity of fossil resources, strains our resource system and necessitates the development of sustainable and innovative strategies for the chemical industry. Our society is currently experiencing constraints imposed by our resource system, which drives industry to increase its overall efficiency by improving existing processes or finding new uses for waste. Food supply chain waste emerged as a resource with a significant potential to be employed as a raw material for the production of fuels and chemicals given the abundant volumes globally generated, its contained diversity of functionalised chemical components and the opportunity to be utilised for higher value applications. The present manuscript is aimed to provide a general overview of the current and most innovative uses of food supply chain waste, providing a range of worldwide case-studies from around the globe. These studies will focus on examples illustrating the use of citrus peel, waste cooking oil and cashew shell nut liquid in countries such as China, the UK, Tanzania, Spain, Greece or Morocco. This work emphasises 2nd generation food waste valorisation and re-use strategies for the production of higher value and marketable products rather than conventional food waste processing (incineration for energy recovery, feed or composting) while highlighting issues linked to the use of food waste as a sustainable raw material. The influence of food regulations on food supply chain waste valorisation will also be addressed as well as our society's behavior towards food supply chain waste. “There was no ways of dealing with it that have not been known for thousands of years. These ways are essentially four: dumping it, burning it, converting it into something that can be used again, and minimizing the volume of material goods – future garbage – that is produced in the first place.” William Rathje on waste (1945–2012) – Director of the Tucson Garbage project.

In this manuscript, the possibility of utilising seawater instead of fresh water and a synthetic mixture of minerals as alternative water and mineral sources in succinic acid (SA) fermentations was investigated. Seawater tolerance experiments demonstrated that the specific growth rate of Actinobacillus succinogenes was only slightly affected when more than 60% synthetic seawater was used, but no major significant inhibition of cell growth and SA production were observed even when fresh water was replaced by 100% synthetic seawater. The possibility of replacing a semi-defined medium with fresh water by wheat-derived media with natural seawater was carried out sequentially. Results showed that besides the usage as a water source, seawater also can be used as a mineral supplement to the wheat-derived media, forming a nutrient-complete medium for succinic acid production. In a fermentation using only wheat-derived medium and natural seawater, 49 g L−1succinic acid was produced with a yield of 0.94 g per g and a productivity of 1.12 g L−1 h−1. Interestingly, compounds present in seawater had a major effect on rates of reactions of a range of transformations of SA including esterifications and amidations in comparison with reactions run under similar conditions using distilled water. While salts and related compounds improved the rates of reaction in the amidation of SA compared to plain water, a significant reduction in activity and catalyst deactivation was found in the esterifications of SA using Starbon® acids as catalysts.

The bioeconomy era will rely on efficient fractionation of renewable resources via integrated biorefineries. The food supply chain waste, despite its inherent variability, could evolve into an important industrial feedstock on account of its availability, versatility, and sustainability, for the production of bio-based products. Waste streams generated from all stages of the life cycle of food products could be refined into different fractions, which will be either purified to high-value molecules or converted via green chemical and/or biotechnological routes for the production of bio-based products. A working group of the EUBis COST Action TD1203 is taking steps to gather a critical mass of knowledge and expertise to create innovation and technological breakthroughs.

In order to recover glucose and polyester from textile waste, enzymatic hydrolysis of textile waste pretreated by different modification methods was investigated. The effects of key factors related to hydrolysis process were evaluated, including substrate loading, temperature, pH, cellulase dosage, and supplementation of β-glucosidase. Results showed that freezing NaOH/urea could contribute to significant increase of the hydrolysis yield compared with untreated textile waste, from 57.7 to 98.3%. Increasing substrate loading from 1 to 7% (w/v) had a negative effect on glucose recovery yield and significant inhibitory effect was observed over 3% substrate loading. Substrate loading at 3% was selected based on glucose yield. The optimal temperature for enzymatic hydrolysis was 50 °C and significant reduction was observed over 60 °C. There was no significant increase of glucose recovery yield when cellulase loading was over 20 FPU/g and β-glucosidase loading was over 10 U/g. Therefore, the optimum enzymatic hydrolysis condition was using 20 FPU/g cellulase and 10 U/g β-glucosidase at 50 °C and pH 5, based on the criterion for minimizing enzyme dosage and maximizing glucose recovery. The maximum glucose recovery yield of 98.3% was achieved after 96 h hydrolysis.