Enzyme sources in industry: Amyloglucosidase (glucoamylase) used for starch-to-glucose conversion is produced by which organism(s)?

Introduction / Context:
Amyloglucosidase (also called glucoamylase) is a key saccharifying enzyme for converting liquefied starch into glucose syrups, high-glucose feeds for isomerization to high-fructose syrups, and other sweeteners. Multiple fungi are known industrial sources.

Given Data / Assumptions:

• The question lists Rhizopus niveus and Endomycopsis fibuliger among options.
• Industry widely uses fungal glucoamylases due to suitable pH/temperature profiles and secretion capacity.

Concept / Approach:
Species in Rhizopus and Endomycopsis (now often reclassified taxonomically) are classic producers of amyloglucosidase, along with Aspergillus species. Both R. niveus and E. fibuliger have been reported to yield active glucoamylase preparations used in starch processing. Therefore, the combined option is correct.

Step-by-Step Solution:

Verification / Alternative check:
Process literature and enzyme catalogs list Rhizopus and Endomycopsis-derived amyloglucosidases for saccharification steps.

Why Other Options Are Wrong:

• Rhizopus niveus only or Endomycopsis only: incomplete.
• Sclerotina libertina: not a standard industrial source of glucoamylase for starch saccharification.

Common Pitfalls:
Conflating alpha-amylase (liquefaction) with amyloglucosidase (saccharification); both are used but produced by different strains and conditions.

Final Answer:
Both (a) and (b)