Where's the Yeast?!
Where's the Yeast?
Where does it occur naturally? Obviously I could buy it at the store, but i'm just curious...
Answers:
Yeasts are chemoorganotrophs as they use organic compounds as a source of energy and do not require light to grow. The main source of carbon is obtained by hexose sugars such as glucose, or disaccharides such as sucrose and maltose. Some species can metabolize pentose sugars such as fructose, alcohols, and organic acids. Yeast species either require oxygen for aerobic cellular respiration (obligate aerobes), or are anaerobic but also have aerobic methods of energy production (facultative anaerobes). Unlike bacteria, there are no known yeast species that grow only anaerobically (obligate anaerobes).
Yeasts are ubiquitous in the environment, but are most frequently isolated from sugar-rich samples. Some good examples include fruits and berries (such as grapes, apples or peaches), and exudates from plants (such as plant saps or cacti). Some yeasts are found in association with soil and insects. Yeast are generally grown in the laboratory on solid growth media or liquid broths. Common media used for the cultivation of yeasts include; potato dextrose agar (PDA) or potato dextrose broth, Wallerstien Laboratories Nutrient agar (WLN), Yeast Peptone Dextrose agar (YPD), and Yeast Mould agar or broth (YM). The antibiotic cycloheximide is sometimes added to yeast growth media to inhibit the growth of Saccharomyces yeasts and select for wild/indigenous yeast species.
Hope this helps! =)
I've studied this a lot. [made my own etc.]. It grows on the skins of grapes and apples.... But the bought stuff is way more reliable. Though it will be fun to try it out.