Panulirus argus and P laevicauda lobster carapace meat, lobster tail parings, whole shrimp tails from Cinnamon shrimp, (Macrobachium amazonicum) and scraps left over from filleting Piaui croaker (Plagioscion squamosissimus) were separated, hydrolysed and then lyophilised and used as individual sources of peptone in media for the cultivation of Escherichia coli. The composition of the test media was: 0.3% meat extract, 0.5% peptone and 0.1% lactose. These new sources of peptone were compared with commercially obtained peptone (OXOID), commonly used in laboratory media, and which served as the control. E coli growth curves for each source of peptone were evaluated using the turbidimetry method and biomass quantification was determined by the dry curve method in order to obtain the respective growth rates for these media. E coli grew faster and for longer using alternative sources of peptone than with the control. The peptone yield from lobster carapace meat was 17.6%, from lobster tail parings 10.2%, from Piaui croaker fish scraps 23% and from whole Ciannamon shrimp tails 12.9%. Growth curves and the biomass figures indicate the feasibility of using these fishery by-products as raw materials for peptone production for microbial media. Copyright © 2005 Society of Chemical Industry