Term: productivity, \(r\) https://doi.org/10.1351/goldbook.P04865 Definition: An economical figure denoting the mass of a product formed per unit reactor volume and unit time. Productivity is often referred to per unit of enzyme or biomass. Related Terms: 1) enzyme (http://doi.org/10.1351/goldbook.E02159). 2) biomass (http://doi.org/10.1351/goldbook.B00660). Source: PAC, 1992, 64, 143. 'Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992)' on page 163 (https://doi.org/10.1351/pac199264010143) Citation: 'productivity, \(r\)' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.P04865 License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.