Amino acid biotechnology — Which microorganism is utilized in industrial processes for producing D- or DL-alanine?

Introduction / Context:
Industrial amino acid production relies on carefully selected microbes and enzymes. Alanine (particularly D- or DL-alanine) is important in pharmaceuticals and as a building block in chemical synthesis, and specific strains are exploited for efficient production and racemization.

Given Data / Assumptions:

• Several coryneform and related bacteria are used in amino acid fermentations.
• Microbacterium ammoniaphilum has been reported for D/L-alanine processes via dehydrogenases/alanine racemase systems.
• Other listed organisms are associated with different amino acids (e.g., Brevibacterium, Corynebacterium glutamicum for L-lysine, glutamate).

Concept / Approach:
Match each organism to its classic industrial product. While multiple platforms exist, the teaching-key association pairs D-/DL-alanine with Microbacterium ammoniaphilum, distinguishing it from lysine/glutamate producers.

Step-by-Step Solution:

Verification / Alternative check:
Bioprocess literature describes D-/DL-alanine production using enzyme systems or microbes like Microbacterium species due to robust racemase/dehydrogenase activity.

Why Other Options Are Wrong:

• Brevibacterium flavum: historically famous for L-lysine, not D-/DL-alanine.
• C. glutamicum: widely used for glutamate and many L-amino acids.
• Arthrobacter paraffineus: not the classical choice for alanine production.

Common Pitfalls:
Assuming all coryneforms produce all amino acids; strain specialization matters greatly.

Final Answer:
Microbacterium ammoniaphilum