Marine sources for biotechnology: Preliminary digestive enzymes assessment of seven decapod species from the southwest Atlantic

Abstract

Marine natural compounds are required by industries to improve and reduce costs of many biotechnological processes. In this work, specific activity of midgut gland digestive enzymes was measured in seven species of decapods. Alkaline and acid peptidase, lipase and amylase activities were registered in Pleoticus muelleri (Pm), Artemesia longinaris (Al), Paralomis granulosa (Pg), Lithodes santolla (Ls), Munida gregaria (Mg), Neohelice granulata (Ng), and Ovalipes trimaculatus (Ot). The highest activities for all the analyzed digestive enzymes were obtained in Pg, Ls, Mg and Ot, which were used for optimum temperature and pH measurements and to test their stability at different temperatures and pH. In general, optimal enzyme temperatures were between 30 and 50 °C in the four crustaceans. Peptidases and lipases from these species showed in general alkaline optimal pH except for those from Ot which presented high activity at the whole pH range (2–12). Amylase from Ot presented its optimal at pH 6–8 and 30–50 °C. Thermal stability of peptidases was elevated at 30 °C for the four species tested (Pg; Ls; Mg and Ot), lipases were stable mainly at 30–50 °C and amylase was stable at 10 °C, 30 °C and 50 °C during the first 30 min of the assay. In general, stability of the four enzymes from Pg was greater at alkaline pH than at acid. The other species showed stability at all pH for the four enzymes. The range of temperature and pH of the tested enzymes activity are coincident with those used in various biotechnological processes and therefore indicates the potential of these enzymes to be used for industrial procedures. Further, most of the species studied are converted into fishery residues, either by processing or by-catch, so their reuse would also contribute to the sustainability of the activity.