Biochemical Engineering and Biotechnology

Extensive application of bioprocesses has generated an expansion in biotechnological knowledge, generated by the application of biochemical engineering to biotechnology. Microorganisms produce alcohols and acetone that are used in industrial processes. The knowledge related to industrial microbiology has been revolutionized by the ability of genetically engineered cells to make many new products. Genetic engineering and gene mounting has been developed to enhance industrial fermentation. Ultimately, these bioprocesses have become a new way of developing commercial products. Biochemical Engineering and Biotechnology demonstrates the application of biological sciences in engineering with theoretical and practical aspects to enhance understanding of knowledge in this field. The book adopts a practical approach, showing related case studies with original research data. It is an ideal text book for college and university courses, which guides students through the lectures in a clear and well-illustrated manner. · Demonstrates the application of biological sciences in engineering with theoretical and practical aspects. · Unique practical approach, using case studies, detailed experiments, original research data and problems and possible solutions. · Gives detailed experiments with simple design equations and the required calculations.
Chapter One Industrial Microbiology

1.1 INTRODUCTION

Microorganisms have been identified and exploited for more than a century. The Babylonians and Sumerians used yeast to prepare alcohol. There is a great history beyond fermentation processes, which explains the applications of microbial processes that resulted in the production of food and beverages. In the mid-nineteenth century, Louis Pasteur understood the role of microorganisms in fermented food, wine, alcohols, beverages, cheese, milk, yoghurt and other dairy products, fuels, and fine chemical industries. He identified many microbial processes and discovered the first principal role of fermentation, which was that microbes required substrate to produce primary and secondary metabolites, and end products.

In the new millennium, extensive application of bioprocesses has created an environment for many engineers to expand the field of biotechnology. One of the useful applications of biotechnology is the use of microorganisms to produce alcohols and acetone, which are used in the industrial processes. The knowledge related to industrial microbiology has been revolutionised by the ability of genetically engineered cells to make many new products. Genetic engineering and gene mounting have been developed in the enhancement of industrial fermentation. Consequently, biotechnology is a new approach to making commercial products by using living organisms. Furthermore, knowledge of bioprocesses has been developed to deliver fine-quality products.

Application of biological sciences in industrial processes is known as bioprocessing. Nowadays most biological and pharmaceutical products are produced in well-defined industrial bioprocesses. For instance, bacteria are able to produce most amino acids that can be used in food and medicine. There are hundreds of microbial and fungal products purely available in the biotechnology market. Microbial production of amino acids can be used to produce L-isomers; chemical production results in both D- and L-isomers. Lysine and glutamic acid are produced by Corynebacterium glutamicum. Another food additive is citric acid, which is produced by Aspergillus niger. Table 1.1 summarises several widespread applications of industrial microbiology to deliver a variety of products in applied industries.

The growth of cells on a large scale is called industrial fermentation. Industrial fermentation is normally performed in a bioreactor, which controls aeration, pH and temperature. Microorganisms utilise an organic source and produce primary metabolites such as ethanol, which are formed during the cells' exponential growth phase. In some bioprocesses, yeast or fungi are used to produce advanced valuable products. Those products are considered as secondary metabolites, such as penicillin, which is produced during the stationary phase. Yeasts are grown for wine- and bread-making. There are other microbes, such as Rhizobium, Bradyrhizobium and Bacillus thuringiensis, which are able to grow and utilise carbohydrates and organic sources originating from agricultural wastes. Vaccines, antibiotics and steroids are also products of microbial growth.

1.2 PROCESS FERMENTATION

The term 'fermentation' was obtained from the Latin verb 'fervere', which describes the action of yeast or malt on sugar or fruit extracts and grain. The 'boiling' is due to the production of carbon dioxide bubbles from the aqueous phase under the anaerobic catabolism of carbohydrates in the fermentation media. The art of fermentation is defined as the chemical transformation of organic compounds with the aid of enzymes. The ability of yeast to make alcohol was known to the Babylonians and Sumerians before 6000 BC. The Egyptians discovered the generation of carbon dioxide by brewer's yeast in the preparation of bread. The degradation of carbohydrates by microorganisms is followed by glycolytic or Embden–Myerhof–Parnas pathways. Therefore the overall biochemical reaction mechanisms to extract energy and form products under anaerobic conditions are called fermentation processes. In the process of ethanol production, carbohydrates are reduced to pyruvate with the aid of nicotinamide adenine dinucleotide (NADH); ethanol is the end product. Other fermentation processes include the cultivation of acetic acid bacteria for the production of vinegar. Lactic acid bacteria preserve milk; the products are yoghurt and cheese. Various bacteria and mold are involved in the production of cheese. Louis Pasteur, who is known as the father of the fermentation process, in early nineteenth century defined fermentation as life without air. He proved that existing microbial life came from preexisting life. There was a strong belief that fermentation was strictly a biochemical reaction. Pasteur disproved the chemical hypothesis. In 1876, he had been called by distillers of Lille in France to investigate why the content of their fermentation product turned sour. Pasteur found under his microscope the microbial contamination of yeast broth. He discovered organic acid formation such as lactic acid before ethanol fermentation. His greatest contribution was to establish different types of fermentation by specific microorganisms, enabling work on pure cultures to obtain pure product. In other words, fermentation is known as a process with the existence of strictly anaerobic life: that is, life in the absence of oxygen. The process is summarised in the following steps:

• Action of yeast on extracts of fruit juice or, malted grain. The biochemical reactions are related to generation of energy by catabolism of organic compounds.

• Biomass or mass of living matter, living cells in a liquid solution with essential nutrients at suitable temperature and pH leads to cell growth. As a result, the content of biomass increases with time.

In World War I, Germany was desperate to manufacture explosives, and glycerol was needed for this. They had identified glycerol in alcohol fermentation. Neuberg discovered that the addition of sodium bisulphate in the fermentation broth favored glycerol production with the utilization of ethanol. Germany quickly developed industrial-scale fermentation, with production capacity of about 35 tons per day. In Great Britain, acetone was in great demand; it was obtained by anaerobic fermentation of acetone–butanol using Clostridium acetobutylicum.

In large-scale fermentation production, contamination was major problem. Microorganisms are capable of a wide range of metabolic reactions, using various sources of nutrients. That makes fermentation processes suitable for industrial applications with inexpensive nutrients. Molasses, corn syrup, waste products from crystallisation of sugar industries and the wet milling of corn are valuable broth for production of antibiotics and fine chemicals. We will discuss many industrial fermentation processes in the coming chapters. It is best to focus first on the fundamental concepts of biochemical engineering rather than the applications.

There are various industries using biological processes to produce new products, such as antibiotics, chemicals, alcohols, lipid, fatty acids and proteins. Deep understanding of bioprocessing may require actual knowledge of biology and microbiology in the applications of the above processes. It is very interesting to demonstrate bench-scale experiments and make use of large-scale advanced technology. However, application of the bioprocess in large-scale control of microorganisms in 100,000 litres of media may not be quite so simple to manage. Therefore trained engineers are essential and highly in demand; this can be achieved by knowledge enhancement in the sheathe bioprocesses. To achieve such objectives we may need to explain the whole process to the skilled labour and trained staff to implement bioprocess know how in biotechnology.

1.3 APPLICATION OF FERMENTATION PROCESSES

Man has been using the fermentative abilities of microorganisms in various forms for many centuries. Yeasts were first used to make bread; later, use expanded to the fermentation of dairy products to make cheese and yoghurt. Nowadays more than 200 types of fermented food product are available in the market. There are several biological processes actively used in the industry, with high-quality products such as various antibiotics, organic acids, glutamic acid, citric acid, acetic acid, butyric and propionic acids. Synthesis of proteins and amino acids, lipids and fatty acids, simple sugar and polysaccharides such as xanthan gum, glycerol, many more fine chemicals and alcohols are produced by bioprocesses with suitable industrial applications. The knowledge of bioprocessing is an integration of biochemistry, microbiology and engineering science applied in industrial technology. Application of viable microorganisms and cultured tissue cells in an industrial process to produce specific products is known as bioprocessing. Thus fermentation products and the ability to cultivate large amounts of organisms are the focus of bioprocessing, and such achievements may be obtained by using vessels known as fermenters or bioreactors. The cultivation of large amounts of organisms in vessels such as fermenters and bioreactors with related fermentation products is the major focus of bioprocess.

A bioreactor is a vessel in which an organism is cultivated and grown in a controlled manner to form the by-product. In some cases specialised organisms are cultivated to produce very specific products such as antibiotics. The laboratory scale of a bioreactor is in the range 2–100 litres, but in commercial processes or in large-scale operation this may be up to 100 m3. Initially the term 'fermenter' was used to describe these vessels, but in strict terms fermentation is an anaerobic process whereas the major proportion of fermenter uses aerobic conditions. The term 'bioreactor' has been introduced to describe fermentation vessels for growing the microorganisms under aerobic or anaerobic conditions.

Bioprocess plants are an essential part of food, fine chemical and pharmaceutical industries. Use of microorganisms to transform biological materials for production of fermented foods, cheese and chemicals has its antiquity. Bioprocesses have been developed for an enormous range of commercial products, as listed in Table 1.1. Most of the products originate from relatively cheap raw materials. Production of industrial alcohols and organic solvents is mostly originated from cheap feed stocks. The more expensive and special bioprocesses are in the production of antibiotics, monoclonal antibodies and vaccines. Industrial enzymes and living cells such as baker's yeast and brewer's yeast are also commercial products obtained from bioprocess plants.

1.4 BIOPROCESS PRODUCTS

Major bioprocess products are in the area of chemicals, pharmaceuticals, energy, food and agriculture, as depicted in Table 1.2. The table shows the general aspects, benefits and application of biological processes in these fields.

Most fermented products are formed into three types. The main categories are now discussed.

1.4.1 Biomass

The aim is to produce biomass or a mass of cells such as microbes, yeast and fungi. The commercial production of biomass has been seen in the production of baker's yeast, which is used in the baking industry. Production of single cell protein (SCP) is used as biomass enriched in protein. An algae called Spirulina has been used for animal food in some countries. SCP is used as a food source from renewable sources such as whey, cellulose, starch, molasses and a wide range of plant waste.

1.4.2 Cell Products

Products are produced by cells, with the aid of enzymes and metabolites known as cell products. These products are categorised as either extracellular or intracellular. Enzymes are one of the major cell products used in industry. Enzymes are extracted from plants and animals. Microbial enzymes, on the other hand, can be produced in large quantities by conventional techniques. Enzyme productivity can be improved by mutation, selection and perhaps by genetic manipulation. The use of enzymes in industry is very extensive in baking, cereal making, coffee, candy, chocolate, corn syrup, dairy product, fruit juice and beverages. The most common enzymes used in the food industries are amylase in baking, protease and amylase in beef product, pectinase and hemicellulase in coffee, catalase, lactase and protease in dairy products, and glucose oxidase in fruit juice.

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Excerpted from BIOCHEMICAL ENGINEERING AND BIOTECHNOLOGY by Ghasem D. Najafpour Copyright © 2007 by Elsevier B.V. . Excerpted by permission of Elsevier. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site. Extensive Application Of Bioprocesses Has Generated An Expansion In Biotechnological Knowledge, Generated By The Application Of Biochemical Engineering To Biotechnology. Microorganisms Produce Alcohols And Acetone That Are Used In Industrial Processes. The Knowledge Related To Industrial Microbiology Has Been Revolutionized By The Ability Of Genetically Engineered Cells To Make Many New Products. Genetic Engineering And Gene Mounting Has Been Developed To Enhance Industrial Fermentation. Ultimately, These Bioprocesses Have Become A New Way Of Developing Commercial Products. Biochemi Cover; Biochemical Engineering And Biotechnology; Copyright Page; Preface; Table Of Contents; Chapter 1. Industrial Microbiology; 1.1 Introduction; 1.2 Process Fermentation; 1.3 Application Of Fermentation Processes; 1.4 Bioprocess Products; 1.5 Production Of Lactic Acid; 1.6 Production Of Vinegar; 1.7 Production Of Amino Acids (lysine And Glutamic Acid) And Insulin; 1.8 Antibiotics, Production Of Penicillin; 1.9 Production Of Enzymes; 1.10 Production Of Baker's Yeast; References; Chapter 2. Dissolved Oxygen Measurement And Mixing; 2.1 Introduction 2.2 Measurement Of Dissolved Oxygen Concentrations2.3 Batch And Continuous Fermentation For Production Of Scp; 2.4 Batch Experiment For Production Of Baker's Yeast; 2.5 Oxygen Transfer Rate (otr); 2.6 Respiration Quotient (rq); 2.7 Agitation Rate Studies; 2.8 Nomenclature; References; Chapter 3. Gas And Liquid System (aeration And Agitation); 3.1 Introduction; 3.2 Aeration And Agitation; 3.3 Effect Of Agitation On Dissolved Oxygen; 3.4 Air Sparger; 3.5 Oxygen Transfer Rate In A Fermenter; 3.6 Mass Transfer Coefficients For Stirred Tanks; 3.7 Gas Hold-up 3.8 Agitated System And Mixing Phenomena3.9 Characterisation Of Agitation; 3.10 Types Of Agitator; 3.11 Gas-liquid Phase Mass Transfer; 3.12 Nomenclature; References; 3.13 Case Study: Oxygen Transfer Rate Model In An Aerated Tank For Pharmaceutical Wastewater; References; 3.14 Case Study: Fuel And Chemical Production From The Water Gas Shift Reaction By Fermentation Processes; References; Chapter 4. Fermentation Process Control; 4.1 Introduction; 4.2 Bioreactor Controlling Probes; 4.3 Characteristics Of Bioreactor Sensors; 4.4 Temperature Measurement And Control 4.5 Do Measurement And Control4.6 Ph/redox Measurement And Control; 4.7 Detection And Prevention Of The Foam; 4.8 Biosensors; 4.9 Nomenclature; References; Chapter 5. Growth Kinetics; 5.1 Introduction; 5.2 Cell Growth In Batch Culture; 5.3 Growth Phases; 5.4 Kinetics Of Batch Culture; 5.5 Growth Kinetics For Continuous Culture; 5.6 Material Balance For Cstr; 5.7 Enzyme Reaction Kinetics; 5.8 Nomenclature; References; 5.9 Case Study: Enzyme Kinetic Models For Resolution Of Racemic Ibuprofen Esters In A Membrane Reactor; References; Chapter 6. Bioreactor Design; 6.1 Introduction 6.2 Background To Bioreactors6.3 Type Of Bioreactor; 6.4 Stirred Tank Bioreactors; 6.5 Bubble Column Fermenter; 6.6 Airlift Bioreactors; 6.7 Heat Transfer; 6.8 Design Equations For Cstr Fermenter; 6.9 Temperature Effect On Rate Constant; 6.10 Scale-up Of Stirred-tank Bioreactor; 6.11 Nomenclature; References; Chapter 7. Downstream Processing; 7.1 Introduction; 7.2 Downstream Processing; 7.3 Filtration; 7.4 Centrifugation; 7.5 Sedimentation; 7.6 Flotation; 7.7 Emerging Technology For Cell Recovery; 7.8 Cell Disruption; 7.9 Solvent Extraction; 7.10 Adsorption; 7.11 Chromatography 7.12 Nomenclature Ghasem D. Najafpour. Description Based Upon Print Version Of Record. Includes Bibliographical References And Index. English Extensive application of bioprocesses has generated an expansion in biotechnological knowledge, generated by the application of biochemical engineering to biotechnology. Microorganisms produce alcohols and acetone that are used in industrial processes. The knowledge related to industrial microbiology has been revolutionized by the ability of genetically engineered cells to make many new products. Genetic engineering and gene mounting has been developed to enhance industrial fermentation. Ultimately, these bioprocesses have become a new way of developing commercial products.

Biochemical Engineering and Biotechnology demonstrates the application of biological sciences in engineering with theoretical and practical aspects to enhance understanding of knowledge in this field. The book adopts a practical approach, showing related case studies with original research data. It is an ideal text book for college and university courses, which guides students through the lectures in a clear and well-illustrated manner.

· Demonstrates the application of biological sciences in engineering with theoretical and practical aspects.
· Unique practical approach, using case studies, detailed experiments, original research data and problems and possible solutions.
· Gives detailed experiments with simple design equations and the required calculations. Extensive application of bioprocesses has generated an expansion in biotechnological knowledge, generated by the application of biochemical engineering to biotechnology. Microorganisms produce alcohols and acetone that are used in industrial processes. The knowledge related to industrial microbiology has been revolutionized by the ability of genetically engineered cells to make many new products. Genetic engineering and gene mounting has been developed to enhance industrial fermentation. Ultimately, these bioprocesses have become a new way of developing commercial products. **Biochemical Engineering and Biotechnology demonstrates the application of biological sciences in engineering with theoretical and practical aspects to enhance understanding of knowledge in this field. The book adopts a practical approach, showing related case studies with original research data. It is an ideal text book for college and university courses, which guides students through the lectures in a clear and well-illustrated manner. · Demonstrates the application of biological sciences in engineering with theoretical and practical aspects. · Unique practical approach, using case studies, detailed experiments, original research data and problems and possible solutions. · Gives detailed experiments with simple design equations and the required calculations.**