食品发酵工艺：绪论

Produced steadily by cell regulations
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Steps in Industrial Fermentation
➢Screen the best producing strain ➢Prepare medium and sterilization ➢Optimize production condition ➢Downstream processing
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Major Products of Industrial Microbiology
➢ Industrial and agricultural products ➢ Fermented Food and Food additives ➢ Products for human and animal health
food industry solvents
nutritional additive and flavour enhancer
industrial
Significance antibiotic
antibiotic
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primary metabolites vs. secondary metabolites
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The product can either be
➢The cell itself: biomass production. ➢A microorganism own metabolite:
a product from a natural or genetically improved strain.
Fermentation is a unique process with great potential
➢Environment friendly ➢Consume less energy ➢Easy to manage
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History of fermentation
Ethanol fermentation was one of the first chemical reactions observed by humans. In nature, various types of food "go bad" as a result of bacterial action. Early in history, humans discovered that this kind of change could result in the formation of products that were enjoyable to consume.
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Pioneers in Microbiology
Anthony van Leeuwenhoek
➢Made the earliest microscopes which magnified up to 300X. ➢Discovered microorganisms.
(1632-1723)
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Leenvenhoek ′ s microscope
（1843-1910）
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Single strain
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Hale Waihona Puke The Nobel Prize in Chemistry 1907
"for his biochemical researches and
his discovery of cell-free fermentation"
Eduard Buchner
Louis Pasteur
➢Showed microbes caused fermentation & spoilage ➢Disproved spontaneous generation of microorganisms ➢Developed aseptic techniques
(1822-1895)
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Microbiologist’s opinion (broad sense) Any process for the production of
a product by the mass culture of microorganisms.
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Definition of Fermentation
similarities differences
Contents
P.M.
S.M
Growth
Yes
No
needed?
Species
No
Yes
specificity?
Production during active growth stage
after growth phase
Examples amino acid, nucleotide, antibiotics, toxin, polysaccharide, vitamin hormones, pigment
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Products from Microorganisms
vinegar 23
Q: Why antibiotics , amino acid and enzymes could be produced by microbial fermentation ?
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Types of microbial products
Germany
1860-1917
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In 1897, Buchner ground up a group of cells with sand until they were totally destroyed. Then he extracted the liquid and added it to a sugar solution. His assumption was that fermentation could no longer occur since the cells were dead. But he was amazed to discover that the cell-free liquid did indeed cause fermentation.
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What is fermentation?
The term fermentation is derived from the Latin verb fervere, to boil, which describes the appearance of the action of yeast on extracts of fruit or malted grain during the production of alcoholic beverages.
Clostridium acetobutyricum
Corynebacterium glutamacium
Xanthomonas campestris
Microorganism
Penicillium chrysogenum
Streptomyces griseus
Significance alcoholic beverages
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Micro-organisms cause changes in the foods which:
➢Extend the shelf life ( preservation ) ➢Producing desirable taste and flavour ➢Improvement of nutritional value ➢Producing required physicochemical properties
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History of Fermentation engineering
➢Start from an ancient time ➢Large scale production
Early 20th century – beverage industry, vinegar, baking yeast, citric (or lactic) acid Late 20th century – development of biotechnology from the antibiotic industrial
Raw Materials
Production microorganism
Fermentation
– have no direct relationship to synthesis of cell material and natural growth
– include antibiotics , mycotoxins, pigment et al.
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Primary metabolite Ethanol
Citric acid Acetone and butanol
Lysine and Glutamic acid Xanthan gum
Secondary metabolite Penicillin
Streptomycin
Microorganism
Saccharomyces cerevisiae
Aspergillus niger
organisms by applying heat – Pasteurisation.
Robert Koch
➢Developed pure culture methods. ➢Established a sequence of experimental steps to show that a specific m.o. causes a particular disease ——Koch’s Postulates
Fermentation is the chemical transformation of organic substances into simpler compounds by the action of enzymes, which are produced by microorganisms such as molds, yeasts, or bacteria.
Fermentation Engineering
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Introduction
➢Concept of fermentation ➢History of fermentation ➢Types of fermentation products ➢Steps in industrial fermentation
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Louis Pasteur’s germ theory
• Old Theory: spontaneous generation
– micro-organisms are the result of decaying matter.
• New Theory: germ theory
– micro-organisms cause decaying matter. – Pasteur showed you could kill the micro-
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Biochemist’s opinion (narrow sense)
Fermentation is an anaerobic process (“life without air”) where energy is produced without the participation of oxygen or other inorganic electron acceptors.
Primary metabolites —— produce during growth stage
– include amino acids, nucleotides, fermentation end products and enzymes
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Secondary metabolites ——produce after growth stage
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stock culture
raw materials
shake flask
medium formulation
seed fermenter fermenter
sterilization
recovery air
purification
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products
Outline of a fermentation process