byprodukt

A byprodukt, or byproduct in English, is a secondary product generated during the manufacture or transformation of a material, in addition to the main product. Byproducts arise whenever the processing of a feedstock yields more than one substance, some of which may be recoverable, usable, or saleable. They are typically distinct from waste in that they can have value or utility.

In industrial and chemical production, byproducts are common in refining, pulping, agriculture, and chemical synthesis. Examples include glycerol, a byproduct of biodiesel production; molasses from sugar manufacture; lignin from paper pulping; and sulfur or various petrochemical byproducts from refining processes. Byproducts may be treated as revenue sources, offsetting some production costs, or redirected to other applications. If their value is low, they may be disposed of as waste, sometimes after treatment to meet environmental standards.

Economic and regulatory considerations often govern how byproducts are reported and managed. Accounting practices may allocate a portion of production costs to byproducts, and environmental regulations may require records, permits, and proper handling to prevent pollution or harm.

In biology, a byproduct refers to a secondary compound produced during metabolism or fermentation that is not the primary objective of the pathway, such as carbon dioxide released during respiration.

A byproduct is not the same as a main product, nor necessarily the same as a co-product or waste, though distinctions vary by context.