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FE 462 BIOCHEMICAL ENGINEERING. INOCULUM. DEFINITION OF INOCULUM Living organisms or an amount of material containing living organisms (such as bacteria or other microorganisms) that is added to initiate or accelerate a biological process, i.e., biological seeding. CRITERIA;
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FE 462 BIOCHEMICAL ENGINEERING INOCULUM
DEFINITION OF INOCULUM • Living organisms or an amount of material containing living organisms (such as bacteria or other microorganisms) that is added to initiate or accelerate a biological process, i.e., biological seeding. • CRITERIA; • Healthy, active state - minimize lag period • Available in sufficient quantities • Suitable morphological form • Free of contamination • Stable - retain its product forming properties
CHOICE OF MICROORGANISM; • Nutritional characteristics - cheap medium • Optimum environmental conditions • Productivity - substrate conversion, product yield, rates. • Amenability to genetic manipulation • Ease of handling and safety (suitability)
Inocula • Pure Monocultures • Advantages and disadvantages of pure cultures • Advantages: easy to obtain (isolate, genetically modify, or purchase; better control of products) • Disadvantages: subject to contamination and genetic change
Processes requiring monocultures i.e PURE CULTURE FERMENTATIONS - industrial ethanol - alcoholic beverages - fermented foods - pharmaceuticals - acetone-butanol - acetic acid - single cell protein - industrial enzymes - biotech products (insulin, growth hormone)
Culture collections Culture collections:for academia, industry, agriculture, medicine and research. specialized in the long-term preservation and storage of microorganisms (documentation associated with these materials.) may be private and profit-oriented, private and non-profit, or public (academic or governmental); cultures may be distributed for a fee or, more rarely, free of cost.
Culture collections supply of industrial microorganisms • AbbreviationNameLocation • ATCC American Type Culture Collection Rockville, MD, U.S. • CBS Centraalbureau voor Schimmenlculturen Baarn, The Netherlands • CDDA Canadian Department of Agriculture Ottawa, Canada • CMI Commonwealth Mycological Institute Kew, United Kingdom • FAT Faculty of Agriculture, Tokyo University Tokyo, Japan • IAM Institute of Applied Microbiology University of Tokyo, Japan • NCIB National Collection of Industrial Bacteria Aberdeen, Scotland • NCTC National Collection of Type Cultures London, United Kingdom • NRRL Northern Regional Research Laboratory Peoria, IL, United States • PCC Pasteur Culture Collection Paris, France
Preservation of pure cultures • 1. Culture Transfer • contamination • genetic change • 2. Refrigeration from 0o to 5oC • short term storage • 3. Low Temperature Freezing • ultra low temp. freezer (-80oC) • liquid nitrogen (-196oC) • 4. Lyophilization • freeze with dry ice and acetone • sublime off water (dries cells without disruption) • use of skim milk, glycerol, or sucrose to protect cells • 5. Mineral Oil • 6. Dry Spores
Mixed Cultures • Advantages and disadvantages of mixed cultures • - Advantages: obtained by enrichment or purchased; can't be patented; contamination not as much of problem • - Disadvantages: control of culture and products is less definite;
Mixed culture fermentations - breads: sour dough, soda cracker - wines - vegetables: pickles, sauerkraut - dairy products: yogurt, sour cream - ensiling - composting - anaerobic digestion - soil and groundwater remediation - bioleaching - microbial enhanced oil recovery - microbial metals recovery - waste treatment
STORAGE AND PRESERVATION; • Essential that isolates / cultures retain desirable characteristics over long periods of time. • METHODS; • Storage at reduced temperatures; • 1. Slopes - refrigerator (4 oC), freezer (-20 oC), • protec beads (-80 oC), • 2. Fungal spores in water (5 oC) • 3. Liquid nitrogen (-150 to -196 oC) • Storage in dehydrated form; • 1. Soil + culture dried. Used for fungi • 2. Lyophilization \ freeze drying. Freezing of culture followed by drying under vacuum which results in sublimination of cell water