Intensification of Biobased Processes
Process intensification is commonly mentioned as one of the most promising development paths for the chemical processing industry and one of the most important progress areas for chemical engineering research. While remaining a hot topic, bioprocessing still poses various important techno-economic and environmental challenges, such as product yields, excessive energy consumption for separations in highly watery systems, batch operation or the downstream processing bottlenecks in the production of biopharmaceutical products. Many of those challenges can be addressed by application of the different process intensification technologies discussed in the present book. The book addresses process intensification in white, green and red biotechnology, both in upstream and downstream processing. Application of an intensified process is demonstrated for the whole spectrum of manufacturing processes. Consequently, the book addresses four clusters of bioproducts: biofuels and commodity, fine chemicals, cosmetics and pharmaceuticals, food products and advanced materials.
Chapter 1 by Noorman, van Winden, Heijnen and van der Lans shows how the four principles of intensification of chemical processes, published by van Gerven and Stankiewicz,1 can improve fermentation processes. The four intensification examples provided demonstrate that debottlenecking of the oxygen transfer capacity is the most important principle, followed by liquid mixing. The next chapter by Boodhoo reviews the progress made in developing and applying rotating reactors for bioprocessing. It focuses on the whole cell fermentation and biotransformations in the rotating fluidized bed, the rotating bed bioreactor, the rotating biofilm contactor and the rotating membrane reactor. Chapter 3 by Kiss and Bîldea presents intensified downstream processing options in the production of the major biofuels, such as biodiesel, bioethanol, biobutanol and dimethyl ether. It reviews several intensified separation technologies: reactive distillation, dividing-wall column, reactive dividing-wall column, catalytic cyclic distillation and heat pump-assisted extractive distillation. In situ product removal is discussed in Chapter 4. Cuellar and Straathof show here how to enhance yield and productivity through the removal of biotransformation products from the reaction mixture. In Chapter 5, de Haan and Birajdar analyze the application of new materials (ionic liquids, deep eutectic solvents, polymers, modifiers and supramolecular structures) and new techniques (ultrasound, microwave, centrifugal and electric field) as a means to increase the extraction efficiency and selectivity in solvent extraction processes. Organic solvent nanofiltration presents another separation method applicable to renewable feedstocks or products. Chapter 6 by Werth and Skiborowski discusses the potential of this membrane technique for important application areas in the oleochemical industry. Integrating separation and reaction in a single device, the Simulated Moving Bed Reactor is a paradigmatic representative of multifunctional reactors, one of the most relevant process intensification strategies. In Chapter 7, Rodrigues, Faria and Graça discuss the application of this multifunctional reactor for production of biodiesel, additives and blending agents. Chapter 8 by Adewuyi addresses intensification of the enzymatic hydrolysis of cellulose using a high multi-frequency ultrasonic reactor and the effects of ultrasound on enzyme stability. The technique has application potential in biofuel production and biorefinery processes. Chapter 9 by Sinha and Rai deals with the hydroprocessing of vegetable oils in microchannel reactors with catalyst coatings. Innovative concepts for reactive separation processes, such as reactive absorption and reactive distillation, that make use of enzymes are discussed in Chapter 10 by Wierschem, Leimbrink, Skiborowski, Heils, Smirnova and Górak. These techniques offer energy and investment savings or improved selectivity by high enantioselectivity and high reaction rates at mild process conditions. Enantioselective reactions are also discussed in Chapter 11 by Shivaprasad and Emanuelsson, which focuses on the integration of upstream and downstream through new equipment concepts like membrane reactors, microreactors, monolithic reactors and rotating disc reactors for enzyme catalyzed reactions. In Chapter 12, Weatherley, Gangu, Scurto and Petera present a short review of the field of enzymatic biotransformations and their application to chemical reactions and products of industrial relevance. Extractive whole-cell biotransformation involving the benzylic chiral hydroxylation of naphthalene and lipolytic hydrolysis of a triglyceride ester using a microbial lipase are discussed in detail. Recent developments in microalgae cultivation and downstream processing with a focus on microalgae biorefinery are presented by Lam, Vermuë, Janssen, Barbosa, Wiffels, Eppink and van den Berg in Chapter 13. Here, the current state-of-development and future directions towards large scale bulk-chemical production from microalgae are discussed. Chapter 14 by Pal discusses process intensification and business sustainability in production of a very important bioproduct i.e. glutamic acid. Integration of appropriate membrane modules with a traditional fermenter leads to an economically viable green process. The next two chapters deal with intensified production methods of recombinant proteins. Baur and Morbidelli describe, in Chapter 15, novel techniques involving continuous or semi-continuous steady-state upstream and downstream processing. They show that continuous perfusion bioreactors enable large reductions in reactor volumes. In Chapter 16, aqueous two-phase extraction is discussed by Brandenbusch, Zeiner and Merz as an alternative to chromatography in purification of biopharmaceuticals. The contribution emphasizes the role of phase thermodynamics in process design. Chapter 17 by Vaghari, Jafarizadeh-Malmiri, Harcourt, Sarabadani, Anarjan and Berenjian deals with functional foods, like essential oils and carotenoids, that are hydrophobic components having low water solubility and consequently low bioavailability. They present an overview on process intensification technologies used in functional foods for increasing the eco-efficiency of the process with the benefit of lower capital costs, substantial energy saving and decreased utilization of solvents. Chapter 18, written by Turk, Perino, Petitcolas and Chemat, presents a panorama of current knowledge on microwave-assisted extractions of antioxidants, flavors, fragrances, natural colors, fats and oils. Industrial scale applications in some pioneering companies are shown. An overview of membrane processes in the food processing industry is presented by Cassano, Conidi and Drioli in Chapter 19. The combination of membrane unit operations leads to high quality products, recovery of high added-value compounds and savings on production and energy costs. The two most important bottlenecks in brewing processes are time consuming enzymatic reactions and the fact that many processes are running simultaneously. In addition, large volumes need to be transported along the production chain. Chapter 20 by Muster-Slawitsch and Brunner highlights several approaches to process intensification and shows that a holistic optimization is important in brewing, as changes in one process may have implications in another. In Chapter 21, Dekkers and van der Goot present novel routes and processing concepts to make meat analogs in order to reduce meat consumption. The chapter ends by reviewing possible raw materials to be used in those applications and the importance of understanding the effect on functional properties when preparing the ingredients. The last two chapters of the book deal with the intensified manufacturing of advanced biomaterials. Direct Digital Manufacturing emerged as a technological innovation that reduces the capital required to achieve the required economy of scale. Chapter 22 by Morouço highlights its use in the pharmaceutical domain, for surgical planning and training and for tissue engineering. These areas of research can overlap the drawbacks of conventional methods, exploring advances in the design and printing processes as a process intensification method. Finally, the last chapter by Stankiewicz shows how alternative energy forms like electric, magnetic, electromagnetic and acoustic fields can be used in manufacturing of advanced biomaterials with a broad range of medical applications, from body parts replacements and tissue repairs to targeted drug delivery and advanced diagnostics.
We are very grateful to Pourya Azadi, MSc, for his valuable assistance in editing the book.
Andrzej Górak and Andrzej Stankiewicz