ADVANCES IN ENVIRONMENTAL BIOTECHNOLOGY AND ENGINEERING 2018 Characterization of cannonball jellyfish (Stomolophus sp. 2) blue protein: a pH-stable pigment Raúl Balam Martínez-Pérez 1,2 & Lourdes Mariana Díaz-Tenorio 1 & Luis Alonso Leyva Soto 1,3 & Pablo Gortáres-Moroyoqui 1 & Leticia García-Rico 4 & Jorge Alberto Rodríguez 2 Received: 30 September 2019 /Accepted: 30 March 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Pigments are present in a broad variety of terrestrial and aquatic organisms. The cannonball jellyfish (Stomolophus sp. 2) is an important fishery resource in the northwest of Mexico and is processed to be traded and consumed as seafood. During the process, water with a soluble blue pigment and other compounds are discarded to the environment. In this work, we present some properties of the blue pigment from Stomolophus sp.2 (S2bp), to decide if it could be considered as a potential value-added waste and avoid the blue proteinaceous pigment wastewater. S2bp was purified to homogeneity and had a molecular mass of 28.0 kDa; this protein exhibited a max at 650 nm, contained Zn 2+ and Cu 2+ metal ions, and was stable from 10 to 50 °C and in a pH range of 3.0 to 13.0 for 1 h. It had halotolerant characteristics maintaining the blue coloration in a broad range of ionic strength (0–4M NaCl) and showed changes in max with chaotropic salts. In addition, S2bp was stable in the presence of organic acids and EDTA and in zwitterionic, anionic, and nonionic detergents at critical micellar concentration. However, oxidant reagents like NaClO and H 2 O 2 decrease the coloration. These results show that the jellyfish pigment is a stable protein which makes it an alternative pigment for the food industry. Keywords Stomolophus sp. 2 . Cnidarian . Blue protein . Pigment . pH-stable protein Introduction Natural pigments are extracted from diverse sources such as plants, insects, animals, and ores (Venil et al. 2013). Blue proteinaceous pigments are present in a variety of animals, plants, bacteria, yeast, and archaea. Animal pig- ments vary in their chemistry and function; these mole- cules are useful to study biochemical adaptations to tech- nological applications. Pigments play important biological roles and can act as sunscreen, camouflage coloration of animals (to escape or hide from predators), visual recep- tion, and the participation in biochemical pathways (Britton 1983). Before synthetic pigments, natural pig- ments from plant extracts and insects were the only source of color available around the world. Natural pigments have been used for many purposes like cotton, wool, and silk coloring and are also used in cosmetic products and in the production of inks, watercolors, and artist’ s paints (Cristea and Vilarem 2006). Moreover, the food industry could use them as colorant or marker. In the last few decades, people interpret synthetic compounds, including pigments, as con- taminants with hazardous effect to humans, animals, and environment; thus, consumers prefer natural compounds (Venil et al. 2013; Zhang et al. 2006); an example of a natural pigment is phycocyanin, a protein-pigment com- plex (Chaiklahan et al. 2012; Wu et al. 2016). Responsible editor: Philippe Garrigues Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-020-08689-1) contains supplementary material, which is available to authorized users. * Jorge Alberto Rodríguez jrodriguez@ciatej.mx 1 Instituto Tecnológico de Sonora, 5 de febrero 818 Sur, Centro, 85000 Ciudad Obregón, Sonora, Mexico 2 Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C., Camino Arenero 1227, El Bajío del Arenal, 45019 Zapopan, Jalisco, Mexico 3 Consejo Nacional de Ciencia y Tecnología, Insurgentes Sur 1582, Crédito Constructor, 03940 Ciudad de Mexico, Mexico 4 Centro de Investigación en Alimentación y Desarrollo, Gustavo Enrique Astiazarán Rosas 46, La Victoria, 83304 Hermosillo, Sonora, Mexico Environmental Science and Pollution Research https://doi.org/10.1007/s11356-020-08689-1