Biochemistry Production of lactic acid through fermentation Done

Biochemistry Production of lactic acid through fermentation Done by Lactobacterias

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

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

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

Energy generation by fermentation Ø Decomposition of organic substances in an anaerobic way Ø Energy generation happens at the diverse ways of fermentation through Substratechain 8 s 9 phosphorylation, that means the direct phosphorylation of ADP under anaerobic conditions. e e e. g. at the creation of Pyruvate and ATP out of Phosphoenolpyruvate and ADP during glycolysis.

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

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 e e Lactic acid fermentation

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

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

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

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

Sources • BROCK et al. : Microbiology, Pearson-Studium, 2006. • MUNK et al: Microbiology. Thieme-Verlag, 2008.