Industrial biotechnology: Which of the following is NOT a typical product made by the fungus Aspergillus niger?

Introduction / Context:
Aspergillus niger is a workhorse of industrial microbiology, producing organic acids and many enzymes. Distinguishing what A. niger commonly produces helps in process selection and exam readiness.

Given Data / Assumptions:

• Citric acid and gluconic acid are famous A. niger products.
• A. niger also secretes multiple hydrolases (e.g., pectinases, amylases, some β-galactosidases depending on strain).
• Lysine is a bulk amino acid typically produced by bacteria.

Concept / Approach:
Citric acid production by A. niger is one of the largest microbial processes. Gluconic acid is also made by A. niger via glucose oxidase pathways. Enzymes like pectinase are standard A. niger products for fruit juice processing. By contrast, industrial L-lysine is produced mainly by Corynebacterium glutamicum and related bacteria via amino acid fermentation.

Step-by-Step Solution:
Confirm A. niger primary acid products: citric and gluconic acids → true. Confirm enzyme secretions: pectinase and some galactosidases → plausible A. niger enzymes. Identify exception: lysine is not a typical A. niger industrial product.

Verification / Alternative check:
Industrial process surveys list A. niger for acids/enzymes, whereas lysine is catalogued under amino acid fermentations driven by Corynebacterium/Escherichia strains.

Why Other Options Are Wrong:
They correspond to well-known A. niger outputs: acids and hydrolases.

Common Pitfalls:
Assuming all commodity chemicals can be made by the same microbe; production strains are highly specialized.

Final Answer:
Lysine.