BACTERIALFERMENTATION

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

BACTERIALFERMENTATION

* Metabolic process

converts sugar to

acids (Anaerobic process)

* Lack of oxygen - becomes

the primary means of

ATP production

LACTIC ACIDFERMENTATION

- 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)

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

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

MIXED-ACIDFERMENTATION

- 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

Importances

Lactose (milk) + lactic acid bacteria → Lactic acid

Two bacteria:Streptococcus thermophilus Lactobacillus bulgaricus

Importances:makes the milk more acidiccausing the proteins in milk to coagulate

Yoghurt ( fermentation of milk)

Bacteria involved:Lactobacillus kimchii, Lactobacillus

sakei were common.

KIMCHI

Stage ❶☞vegetables are submerged in a brine.

Stage❷☞Lactose + sugars lactic acid.

Importances:classic tangy flavourpreserve food.

Benefits of FermentationBenefit Raw material Fermented

foodPreservation Milk Yoghurt,

cheeseEnhancement

of safety-Acid production Fruit Vinegar-Acid and alcohol

productionBarley Beer

Improvement of flavour

Vegetables Kimchi

Enhancement of nutritional

value

Milk Acidophilus yoghurt

Agricultural 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

THANK YOU!