(Group10)bacterial fermentation

SB20103 Metabolism

1. BACTERIAL FERMENTATION LACTIC ACID FERMENTATION MIXED-ACID FERMENTATION IMPORTANCES OF THE FERMENTATION KOAY BOON KEAT TONG KAI LOON GAO LE EE CAI FENG EMMANUEL JUDE JIMY VINCENT YATIN JUMAAIAH BINTI TAASA TUTTYCIA MITCHEL ANAK SEAT

2. BACTERIAL FERMENTATION * Metabolic process converts sugar to acids (Anaerobic process) * Lack of oxygen - becomes the primary means of ATP production

3. LACTIC ACID FERMENTATION - biological process by which glucose and other 6C sugars are converted into cellular energy and the lactic acid. - lactic acid bacteria = gram-positive non-spore forming bacteria ( cocci or rods) - classified into two fermentative patterns => homofermentative pathway (lactic acid) => heterofermentative pathway (lactic acid + ethanol + CO2)

4. - Undergo by bacteria such as Streptococcus sp. and some types of Lactobacillus sp .

5. - Undergo by bacteria such as Leuconostoc sp. and some types of Lactobacillus sp .

6. MIXED- ACID FERMENTATION - used by mixed-acid fermenters such as Escherichia coli - formed 3 different acids – acetic, lactic and succinic from fermentation of glucose - ethanol, CO2 and H2 also formed during the fermentation

7. Importances

8. Lactose (milk) + lactic acid bacteria → Lactic acid Two bacteria: Streptococcus thermophilus Lactobacillus bulgaricus Importances : makes the milk more acidic causing the proteins in milk to coagulate Yoghurt ( fermentation of milk)

9. Bacteria involved: Lactobacillus kimchii , Lactobacillus sakei were common. Kimchi Stage ❶ ☞vegetables are submerged in a brine. Stage ❷ ☞Lactose + sugars lactic acid. Importances : classic tangy flavour preserve food .

10. Benefits of Fermentation Benefit Raw material Fermented food Preservation Milk Yoghurt, cheese Enhancement of safety -Acid production Fruit Vinegar -Acid and alcohol production Barley Beer Improvement of flavour Vegetables Kimchi Enhancement of nutritional value Milk Acidophilus yoghurt

11. A gricultural crops Make silage exposure of crops to lactic acid bacteria fermentation activity lowers pH on the surface of the crop preventing colonization of unwanted microorganisms

12. THANK YOU!