prototrophic, prototrophism 1. Denoting the ability to undertake anabolism or to obtain nourishment from a single source, as with iron, sulfur, or nitrifying bacteria or photosynthesizing plants. 2. Certain bacteria requiring only inorganic substances for growth. 3. Certain microorganisms requiring no specific nutriments for growth. 4. Bacteria ... Found on http://www.wordinfo.info/words/index/info/view_unit/2191/8