How yeast multiplication?

Yeast multiplication & growth
- Yeasts normally reproduces by budding
- During budding a small bubble from the mother cell is formed which a part of the cytoplasm as well as a daughter nucleus
- In some yeast strains the mother & daughter cells separate from one another completely
- In other strains the cells remain connected to one another & form chains log cell number
- The growth is divided into six phase;
1. Lag phase
- Is an activation of metabolism
- The length of phase depends on type of organism & condition
- The length of phase varies greatly
2. Acceleration phase
- The rate of division continuously increases
3. Exponential phase (logarithmic growth or log phase)
- The growth rate is constant & maximal, which the cell number doubles
- The time period is minimal , it’s about 90-120 min
4. Deceleration phase
- Because of reduction in the amount of nutrient substrate or an increase in the amount of inhibiting metabolic products
- The growth rate is decreased
5. Stationary phase
- The number of microorganisms remain constant
- There is balance between the number of newly formed cells & the cells which die
6. Declining phase
- The rate of cell death exceeds the rate of new cell formation
- The cell number therefore decreases

The duration & size of the growth phases are influenced by;
1.Water
- Is the main component of living material & important in the life process
- Microorganism are only able to develop in substrates which contain at least 15% water content
2. pH
- Yeast growth preferably at acidic pH
- Microorganism differ from one another with their optimal pH
3. Temperature
- Every microorganism has its optimum temperature
- Yeast genus Saccharomyces this is usually temperature between 0 oC & 40 oC
- The optimum growth temperature being about 25-30 oC
4. Oxygen
- Important for yeast growth
5. Nutrient
- The substrate must contain all the nutrients required for growth