Q. With reference to the usefulness of the by-products of sugar industry, which of the following statements is/are correct?

1. Bagasse can be used as biomass fuel for the generation of energy.
2. Molasses can be used as one of the feedstocks for the production of synthetic chemical fertilizers.
3. Molasses can be used for the production of ethanol.

Select the correct answer using the codes given below. (UPSC Prelims 2013)
Answer: 1 and 3 only
Notes: The correct answer is [C] 1 and 3 only.This question tests your knowledge of industrial by-products and their ecological/economic applications. While the sugar industry is primarily about sucrose, its "waste" products are some of the most versatile materials in bio-energy and manufacturing.

• 1. Bagasse as biomass fuel: (Correct) Bagasse is the dry, pulpy fibrous residue that remains after crushing sugarcane to extract juice. It is widely used in sugar mills for cogeneration (producing both heat and electricity). Because it is a renewable resource with a high calorific value, it serves as an excellent biomass fuel.
• 2. Molasses for synthetic chemical fertilizers: (Incorrect) Molasses is a thick, dark syrup left after the crystallization of sugar. While it is rich in nutrients and can be used as a soil conditioner or organic fertilizer (and even as animal feed), it is not a feedstock for synthetic chemical fertilizers (like Urea), which are typically derived from natural gas (ammonia).
• 3. Molasses for ethanol production: (Correct) This is one of the most significant uses of molasses today. Through the process of fermentation and distillation, molasses is converted into industrial alcohol and ethanol. This is a pillar of India's Ethanol Blending Programme (EBP) to reduce petroleum imports.