Valorization of shrimp Metapenaeus monoceros bio-waste as a source of bioactive protein hydrolysate

Mediterranean sea is threatened by a large number of factors such as habitat alteration, urbanization, climate change, pollution and more specifically by the introduction of autochton and non-native species. Shrimps are caught all along the Tunisian coasts. They are found in the Gulf of Gabes area, wherein the largest concentrations of these species are located, especially the king shrimp Penaeus kerathurus. In addition, fishing with both trawlers and inshore fishing units have been recorded as relatively large quantities of another shrimp species, commonly known as white or speckled shrimp, Metapenaeus monoceros. The efficiency of the proteolytic strain Anoxybacillus kamchatkensis M1V in the fermentation of speckled shrimp by-product was investigated for the recovery of a deproteinized bioactive hydrolysate. The biological activities of the resulting hydrolysate were also examined by applying several antioxidant and enzyme inhibitory assays. The strain M1V was found to produce high level of protease activity (2,000 U/mL) when grown in media containing only shrimp powder at 25 g/L. The obtained hydrolysate showed a significant enzymatic inhibitory potential against acetylcholinesterase, tyrosinase, amylase, and angiotensin I convertase, and a strong antioxidant activity.