Summary Microbes: Fermentation, Human Microbiome

Fermentation and Human Microbiome
> fermentation - used when oxygen and other external
electron acceptors unavailable
• pyruvate converted to other organic substances to
gegenerate NAD+
• glycolysis can continue to produce ATP from glucose
• glucose is only partially broken down - inefficient (2,3
ATP/glucose)
• only made via SLP, anaerobic
>
- biochemical identification
• pH indication - fermentation produces acids
- lower pH and changes color, durham tube captures Co2
> fermented foods
-


• preservation, improves digestibility, add nutrients,
detoxify, provide probiotics
• glucose fermentation most common in food
fermentation
- different microorganisms ferment glucose to different
products (ie. lactobacillus to lactic acid, propiniobacterium to
propionic acid)
>
- sacchyromyces cerevisiae - bakers/brewers yeast
• when oxygen available, undergo cellular respiration
• when oxygen scarce, use fermentation
vegetable fermentation
>
-


• soybeans contain phytate and lectins - inhibit
absorption by intestines, upset digestion and induce
autoimmune diseases
• fermentation improves digestibilty of soy
• sauerkraut, kimchi
alkaline fermentation
-


• natto - soybean incubated with bacillus natto
• pidan - preserved duck eggs
>
- human microbiome - 38 trillion micorbes
• vary among people due to age, diet, location
• newborns colonized during birthing process and
environmental contact
• most normal microbiota harmless - protects us by
pushing out potential pathogens