Feedstocks for ethanol manufacture Across beverage and fuel applications, which raw materials are used as substrates for industrial ethanol production?

Introduction / Context:
Substrate choice determines the process route and cost structure in ethanol production. Fermentable sugars may be available directly (sucrose sources) or generated by pretreating and hydrolyzing polymeric carbohydrates.

Given Data / Assumptions:

• Industrial processes use sugars derived from starch, sucrose, or cellulose/hemicellulose.
• Different pretreatments are required depending on feedstock.

Concept / Approach:
Starch must be liquefied and saccharified (alpha-amylase, glucoamylase). Sucrose streams like cane juice or molasses can be fermented after clarification. Lignocellulosics (wood, ag residues) need pretreatment and enzymatic hydrolysis to yield hexoses and pentoses for fermentation.

Step-by-Step Solution:

Verification / Alternative check:
Commercial plants operate on corn (starch), sugarcane (sucrose), and pilot/commercial facilities on cellulosics, validating all routes.

Why Other Options Are Wrong:

• “Only pure glucose”: unnecessarily restrictive and not representative of industry.

Common Pitfalls:
Ignoring pretreatment needs for lignocellulosics; assuming identical yields and inhibitors across substrates.

Final Answer:
All of the above