Microbial carotenoids: Which organism(s) are commonly used for industrial or experimental production of beta-carotene?

Introduction / Context:
Beta-carotene is a carotenoid pigment used as a provitamin A and natural colorant. Several filamentous fungi are known carotenoid producers. The question asks which among the listed organisms are used for beta-carotene production.

Given Data / Assumptions:

• Target product: beta-carotene.
• Candidate producers include zygomycetes such as Blakeslea trispora and Phycomyces blakesleeanus, and related genera.
• Industrial relevance and experimental literature are both in scope.

Concept / Approach:
Blakeslea trispora is widely recognized for industrial-scale carotenoid production using mating of + and − strains to boost titers. Phycomyces blakesleeanus is a classical model for carotenoid biosynthesis and can be leveraged for production. Choanephora (historically “Cnoanephora”) cucurbitarum is another carotenoid-forming fungus reported to synthesize beta-carotene and related pigments, although its industrial prominence is lower than B. trispora.

Step-by-Step Solution:
List known fungal carotenoid producers.Identify those with documented beta-carotene synthesis.Confirm industrial versus experimental usage; include all valid producers.Conclude that all three listed organisms qualify.

Verification / Alternative check:
Industrial case studies frequently feature B. trispora; academic literature documents carotenoid biosynthesis in Phycomyces and Choanephora species.

Why Other Options Are Wrong:
Selecting any single organism ignores the broader set of known producers.

Common Pitfalls:
Equating “most common industrial producer” with “only producer.” Multiple fungi can synthesize beta-carotene under the right conditions.

Final Answer:
All of these