Question

Which one of the following is a lactate producing bacteria?

• A. Bacteroides ruminicola
• B. Megasphaera elsdenii
• C. Succinomonas amylolytica
• D. Streptococcus bovis

Hint:

Rumen Microbes:
Lactate PRODUCER = Streptococcus bovis, Lactobacillus spp.
Lactate UTILIZER = Megasphaera elsdenii, Selenomonas ruminantium.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Rumen microbiology and acute lactic acidosis: rapid fermentation of non-structural starches by Streptococcus bovis produces massive amounts of D/L-lactate.
Key Formula or Approach:
\[ \text{Starch / Soluble Sugars} \xrightarrow{\text{Streptococcus bovis}} \text{Lactic Acid (Rapid Rumen pH Drop } < 5.0) \]

Step 2: Detailed Explanation:
In rumen microbiology:
1. {Streptococcus bovis is a rapidly proliferating, facultatively anaerobic Gram-positive coccus that utilizes soluble carbohydrates to produce Lactic Acid (Lactate) as its primary end-product. During sudden high-grain/carbohydrate feeding, S. bovis blooms explosively, driving acute ruminal acidosis.
2. {Megasphaera elsdenii is the primary lactate-utilizing bacterium in the rumen (converts lactate to propionate).
3. Prevotella (Bacteroides) ruminicola produces acetate/succinate.
4. Succinomonas amylolytica produces succinate and acetate.

Step 3: Final Answer:
Thus, Streptococcus bovis is a lactate producing bacteria, corresponding to option (D).