1. Production of lactic acid through fermentation
Biochemistry
Production of lactic acid through fermentation
Done by Lactobacterias

2. Lactic acid fermentation
Glucose
2 ADP
2 NAD+
Glycolysis
2 ATP
2 NADH + H+
2 Pyruvate
Lactic acid fermentation
2 NAD+
2 Lactate

3. Composition of NAD+
→ Regeneration of NAD+, which is consumed during glycolysis.
Nicotinamid
Purine-Base Adenine
2 Phosphate-groups
Sugar Ribose
Sugar Ribose

4. Goal of fermentation
→ Regeneration of NAD+, which is cosumed during glycolysis.
Oxidized form: is built during fermentation
Reduced form: is built during glycolysis

5. Energy generation by fermentation
Decomposition of organic substances in an anaerobic way
Energy generation happens at the diverse ways of fermentation through Substratechain8s9phosphorylation, that means the direct phosphorylation of ADP under anaerobic conditions.
e.g. at the creation of Pyruvate and ATP out of Phosphoenolpyruvate and ADP during glycolysis. e e

6. Types of lactic acid fermentation
Lactic acid bacterias
Homofermentative
Heterofermentative
Decompostition of Hexoses by Glycolysis
Single Ferntationproduct:Lactate
Energy gerneration:
2 Mol ATP per Mol Hexose
Decomposition of Hexoses by Phospho-ketolase-Way
Fermentationproducts: CO2, Ethanol and Lactate
Energy gerneration:
1 Mol ATP per Mol Hexose

7. Homofermentative lactic acid fermentation
1. Step: Glycolysis
Problem: Glycolysis cosumed NAD+
In the next Step, of tzhe lactic acid fermentation, NAD+ will be regernerated again. 2 2 2
Lactic acid fermentation e e

8. 2. Step: actual lactic acid fermentation
Homofermentative lactic acid fermentation
2. Step: actual lactic acid fermentation
NADH+H+
-NAD+
Is available again for glycolysis
Pyrovate
Lactate
Acidrestion of
the latic acid

9. Alcoholic fermentation
Lactic acid fermentation
Alcoholic fermentation
Glucose
2 ADP
2 NAD+
2 NAD+
2 ADP
2 NADH + H+
2 ATP
2 NADH + H+
2 ATP
2 Pyruvate
2 CO2
2 Ethanal
2 NAD+
2 NAD+
2 Lactate
2 Ethanol

10. Bacterias of the lactic acid fermentation
Commonalities:
Obligated fermenter, which are oxygen tolerant
Ferment only sugar,
They have beta-Galactosidase, which splits Lactose in Glucose and Galactose

11. Bacterias of the lactic acid fermentation
Cell form and arrangement
species
Coccus (in chains)
Homofermentative:
Streptococcus
Enterococcus
Lactococcus
Pediococcus
Rods / Bacillus (in chains)
Lactobacillus
(L. delbrueckii and L. plantarum)
Heterofermentative:
- Lactobacillus

12. Sources Brock et al.: Microbiology, Pearson-Studium, 2006.
Munk et al: Microbiology. Thieme-Verlag, 2008.