Nature of YeastWhereisyeastfoundinnature?Ontheskinsoffruitsandberries(suchasgrapes,apples,orpeaches)Inexudatesfromplants(suchasplantsapsorcacti)SomeyeastsarefoundinassociationwithsoilandinsectsChenHangzi
Nature of Yeast Where is yeast found in nature? On the skins of fruits and berries ( such as grapes, apples, or peaches) In exudates from plants (such as plant saps or cacti) Some yeasts are found in association with soil and insects
Nature of YeastTemperature:12°C-40°CCooltemperature(below15°C)Stress Condition > DormancycellsWarmtemperature(15-30°C)Optimaltemperatureforrapidgrowthyeast(25-35oCHightemperature(40°C)Stress Condition → Arrest growthpH:2.8-8.0 (optimal pH4.5-5.0)(耐干)desiccationtoleranceosmotolerance(耐高渗)ChenHangzi
Nature of Yeast Temperature: 12oC-40oC Cool temperature (below 15oC) Stress Condition Dormancy cells Warm temperature (15 – 30oC) Optimal temperature for rapid growth yeast (25-35oC) High temperature (40oC) Stress Condition Arrest growth pH:2.8-8.0 (optimal pH4.5-5.0) desiccation tolerance (耐干) osmotolerance (耐高渗)
facultativeanaerobes（兼性厌氧菌）Aerobicrespiration:CgH12O6 + 6 02 > 6 CO2 + 6 H,0Alcoholicfermentation:C,H1,O > 2 C,H,OH + 2 CO2CO,HHH-C-OH0CH,2ADPohenHangz
facultative anaerobes（兼性厌氧菌）： Aerobic respiration： C6H12O6 + 6 O2 → 6 CO2 + 6 H2O Alcoholic fermentation： C6H12O6 → 2 C2H5OH + 2 CO2