Step 1: Understanding the Concept:
Heterofermentative lactic acid bacteria utilize metabolic pathways different from standard glycolysis (Embden-Meyerhof-Parnas pathway) to ferment hexose sugars, producing various organic acids and carbon dioxide.
Step 2: Detailed Explanation:
Bacteria belonging to the genus Bifidobacterium (highly important probiotic gut bacteria) ferment glucose using a unique biochemical pathway.
Because they lack the key glycolytic enzymes aldolase and glucose-6-phosphate dehydrogenase, they utilize the enzyme fructose-6-phosphate phosphoketolase (F6PPK) to split hexose sugars.
This pathway is known as the Hexose Phosphoketolase Pathway, or more commonly, the Bifidus pathway (or "bifid shunt").
The overall reaction of this pathway converts 2 moles of glucose into 3 moles of acetate and 2 moles of lactate, generating 5 moles of ATP:
\[ 2\text{ Glucose} + 5\text{ ADP} + 5\text{ P}_i \longrightarrow 3\text{ Acetate} + 2\text{ Lactate} + 5\text{ ATP} \]
Let us review the other options:
- Otto Meyerhof & Jakub Parnas pathways: These refer to the classic homofermentative Embden-Meyerhof-Parnas (EMP) glycolytic pathway.
- Malonic pathway: Involved in fatty acid synthesis.
Step 3: Final Answer:
Therefore, the Hexose Phosphoketolase Pathway is also called the Bifidus pathway.