MCB 422 — Industrial Microbiology: Lecture Note

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LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: MCB 422 Couse title: Industrial Microbiology Course unit: 3 Units Series 1: Microorganisms of Industrial Importance and Screening for Productive Strains Part 1 Microorganisms of industrial importance • 1.1.1 Characteristics of industrial microorganisms • 1.1.2 Commonly used microbial groups (bacteria, fungi, yeasts, actinomycetes) • 1.1.3 Examples of industrial applications Part 2 Sources of industrial microorganisms • 1.2.1 Natural habitats and isolation methods • 1.2.2 Culture collections as sources • 1.2.3 Preservation and maintenance for industrial use Part 3 Screening for productive strains • 1.3.1 Principles of strain screening • 1.3.2 Primary screening methods • 1.3.3 Secondary screening and productivity evaluation Part 4 Criteria for selecting industrial strains • 1.4.1 Genetic stability and productivity • 1.4.2 Safety and regulatory considerations • 1.4.3 Economic feasibility and scalability Introduction Microorganisms are at the heart of industrial microbiology, serving as tiny factories that produce valuable products ranging from antibiotics and enzymes to vitamins and organic acids. Their importance lies not only in their diversity but also in their ability to be harnessed for large-scale production. For industries, identifying and selecting the right strains is critical, as it determines efficiency, quality, and economic viability. This Series sets the foundation for the course by

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS introducing you to the microorganisms most commonly used in industrial processes and the methods employed to screen them for productivity. The aim of this Series is to familiarise you with industrially important microorganisms, their sources, and the principles of strain screening, while equipping you with the knowledge to evaluate and select strains based on defined criteria. We shall commence this Series by examining microorganisms of industrial importance, focusing on their characteristics, common groups, and applications. Next, we will move on to explore the sources of industrial microorganisms, including natural habitats and culture collections. Following that, we will consider the principles and methods of screening for productive strains, distinguishing between primary and secondary screening approaches. Finally, we will wrap up by discussing the criteria for selecting industrial strains, such as genetic stability, safety, and economic feasibility, thereby rounding off the Series with a clear understanding of how microorganisms are chosen for industrial use. Series Learning Outcomes Upon completing this Series, you should be able to: • define microorganisms of industrial importance and describe their key characteristics, • identify major microbial groups commonly used in industrial microbiology, • explain examples of industrial applications of microorganisms, • describe natural sources and isolation methods of industrial microorganisms, • explain the role of culture collections as sources of industrial strains, • demonstrate knowledge of preservation and maintenance methods for industrial microorganisms, • explain the principles of strain screening in industrial microbiology, • differentiate between primary and secondary screening methods, • analyse productivity evaluation techniques used in strain screening, • identify criteria for selecting industrial strains based on genetic stability, • evaluate safety and regulatory considerations in strain selection, and • assess economic feasibility and scalability when choosing productive strains. 1.1 Microorganisms of Industrial Importance Microorganisms are central to industrial microbiology because they act as biological factories, producing a wide range of valuable products such as antibiotics, enzymes, organic acids, vitamins, and alcoholic beverages. Their importance lies in their diversity, adaptability, and ability to be cultivated under controlled conditions for large-scale production. In this Part, we

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS will examine their characteristics, the major microbial groups used, and examples of their industrial applications. 1.1.1 Characteristics of industrial microorganisms Industrial microorganisms are microbial species that can be exploited for the production of useful products or processes. They are selected based on specific characteristics such as: • High productivity of desired metabolites or enzymes • Genetic stability to ensure consistent performance • Ability to grow rapidly on inexpensive substrates • Tolerance to industrial conditions such as temperature, pH, and oxygen levels • Safety, meaning they are non-pathogenic and suitable for large-scale use Fill in the blank: Industrial microorganisms must be ______ stable to ensure consistent performance during production. Figure 1.1 Characteristics of industrial microorganisms 1.1.2 Commonly used microbial groups Several microbial groups are widely used in industrial microbiology: • Bacteria: e.g., Bacillus subtilis for enzyme production, Corynebacterium glutamicum for amino acids. • Fungi: e.g., Aspergillus niger for citric acid production, Penicillium chrysogenum for antibiotics. • Yeasts: e.g., Saccharomyces cerevisiae for beer, wine, and ethanol production.

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Actinomycetes: e.g., Streptomyces species for antibiotics such as streptomycin. These groups are chosen because of their proven ability to produce metabolites and withstand industrial fermentation conditions. Fill in the blank: The yeast commonly used in beer and wine production is ______ cerevisiae. Plate 1.1 Microbial groups of industrial importance 1.1.3 Examples of industrial applications Industrial microorganisms are applied in diverse sectors: • Food and beverages: Yeasts for alcoholic drinks, lactic acid bacteria for yoghurt. • Pharmaceuticals: Fungi and actinomycetes for antibiotics, bacteria for vaccines. • Agriculture: Microbial biofertilisers and biopesticides. • Chemicals: Production of organic acids, amino acids, and vitamins. • Enzymes: Microbial enzymes used in detergents, textiles, and paper industries. Fill in the blank: Aspergillus niger is widely used for the industrial production of ______ acid. Selected industrial applications of microorganisms

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS • Food and beverages: beer, wine, yoghurt • Pharmaceuticals: antibiotics, vaccines • Agriculture: biofertilisers, biopesticides • Chemicals: organic acids, amino acids, vitamins • Enzymes: detergents, textiles, paper Quick Recap: • Industrial microorganisms are selected for productivity, genetic stability, rapid growth, tolerance, and safety. • Common groups include bacteria, fungi, yeasts, and actinomycetes. • Applications span food, pharmaceuticals, agriculture, chemicals, and enzyme production. Pilot questions 1.1 1. Industrial microorganisms must be ______ stable to ensure consistent performance during production. 2. The yeast commonly used in beer and wine production is ______ cerevisiae. 3. Aspergillus niger is widely used for the industrial production of ______ acid. 4. Name one bacterial species used in amino acid production. 5. Mention one agricultural application of industrial microorganisms. 1.2 Sources of Industrial Microorganisms Industrial microorganisms must be obtained from reliable sources to ensure productivity, safety, and consistency in large-scale applications. These sources include natural habitats, culture collections, and preservation methods that maintain microbial viability for long-term use. In this Part, we will explore how microorganisms are isolated from nature, how culture collections serve as repositories, and how preservation techniques safeguard strains for industrial purposes. 1.2.1 Natural habitats and isolation methods Natural habitats are environments where microorganisms naturally occur, such as soil, water, plants, and animals. These habitats are rich reservoirs of microbial diversity, making them valuable sources for industrial strains. Isolation methods involve techniques used to separate and identify microorganisms from mixed populations. Common methods include serial dilution, selective media, and enrichment cultures. These approaches help to obtain pure cultures that can be tested for industrial potential. Fill in the blank: Soil and water are examples of natural ______ where microorganisms can be isolated for industrial use. 1.2.2 Culture collections as sources

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Culture collections are organised repositories that maintain and distribute microbial strains for research and industrial use. They provide authenticated strains with documented properties, ensuring reliability and reproducibility. Examples include the American Type Culture Collection (ATCC) and the National Collection of Industrial Bacteria (NCIB). Culture collections are essential because they: • Guarantee genetic stability of strains • Provide access to rare or specialised microorganisms • Facilitate international collaboration and exchange of strains Fill in the blank: Organised repositories that maintain and distribute microbial strains for industrial use are called culture ______. 1.2.3 Preservation and maintenance for industrial use Preservation methods are techniques used to maintain microorganisms in a viable state for long periods without losing their properties. Common methods include refrigeration, lyophilisation (freeze-drying), and cryopreservation in liquid nitrogen. Maintenance methods involve periodic sub-culturing under controlled conditions to keep strains active. While maintenance ensures short-term viability, preservation is crucial for long-term stability. Fill in the blank: The process of freeze-drying microorganisms for long-term storage is known as ______. Preservation methods for industrial microorganisms • Refrigeration: short-term storage at low temperatures • Lyophilisation: freeze-drying for long-term preservation • Cryopreservation: storage in liquid nitrogen • Periodic sub-culturing: maintenance for short-term use Quick Recap: • Natural habitats such as soil and water are primary sources of industrial microorganisms. • Culture collections provide authenticated strains with documented properties. • Preservation and maintenance methods ensure microorganisms remain viable and stable for industrial use. Pilot questions 1.2 1. Soil and water are examples of natural ______ where microorganisms can be isolated for industrial use.

LA-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 2. Organised repositories that maintain and distribute microbial strains for industrial use are called culture ______. 3. The process of freeze-drying microorganisms for long-term

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