Amino acid biotechnology: Which organisms are used for the industrial production of the essential amino acid L-lysine?

Introduction / Context:
L-lysine is a high-volume amino acid used in animal feeds and food fortification. Its commercial production is a flagship example of microbial strain development, metabolic engineering, and fed-batch fermentation optimization.

Given Data / Assumptions:

• We evaluate three closely related actinobacteria used historically and currently for amino acid fermentations.
• Strain designations such as FA 1-30 indicate improved production phenotypes.
• We assume standard sugar-based aerobic fermentations with downstream crystallization.

Concept / Approach:
Species from the Corynebacterium/Brevibacterium group are the established industrial producers of L-lysine. Both Corynebacterium glutamicum and Brevibacterium flavum (including specific high-producing mutants like FA 1-30) appear throughout industrial literature and patents as producers scaled to hundreds of thousands of tons globally.

Step-by-Step Solution:

Verification / Alternative check:
Reviews on amino acid biotechnology and industry case studies consistently document these organisms as lysine workhorses with extensive genetic improvements (feedback-resistant pathways, transporter engineering, and oxygen transfer optimization).

Why Other Options Are Wrong:

• Any single-organism choice is incomplete.
• “None of these” contradicts well-known industrial practice.

Common Pitfalls:
Confusing glutamate and lysine production strains; overlooking that production names may reflect legacy classification between Brevibacterium and Corynebacterium.

Final Answer:
All of these