[en] The cephalopod fishing industry has been growing consistently since the second half of the 20th century until its stabilization in the last decade. In this context, the valorization of so called "waste" acquires special relevance from the point of view of the circular economy, and even more considering the economic potential and the environmental benefit derived from its use in sustainable processes or bioprocesses. Among these by-products are the endoskeletons/pens of the most captured cephalopod species globally, the jumbo squid (Dosidicus gigas). From them, chitin and chitosan can be obtained (both compounds of great commercial interest), generating during their production two liquid effluents with a quite remarkable soluble protein content. In this report, it has been studied and confirmed the feasibility of these effluents as a source of organic nitrogen (proteins) was studied and confirmed to replace the commercial peptones present in a specific culture medium (MRS) for the growth of probiotic lactobacteria such as Lactobacillus plantarum and Leuconostoc mesenteroides, as well as in another broth (Marine Broth) commonly used for the development of probiotic marine bacteria such as Pseudomonas fluorescens and Phaeobacter sp. To this aim, multiple fermentations were carried out in alternative and commercial media, quantifying the biomass produced throughout the culture time, as well as the production of the most important metabolites, and the consumption of soluble protein and glucose at each sampling time. All this was carried out using a combination of microbiological, analytical and chromatographic techniques, with the predictive modeling of experimental data using an unstructured mathematical model. The effluents proved to be (especially the chitin derivative) excellent protein substrates assimilable to commercial peptones. When comparing alternative and commercial media, a reduction of around 4 times in the production costs of biomass and lactic acid from lactobacteria was estimated. Such improvement increased up to 400 times in the case of biomass production from marine bacteria. Both effluents could be part of a possible commercial formulation since they present similar nutritional capacities at much more competitive costs.

[gl] A industria pesqueira de cefalópodos foi crecendo de maneira constante dende a segunda metade do século XX ate a súa estabilización na última década. Neste contexto, a valorización dos considerados "desfeitos" é unha cuestión que adquire unha especial relevancia dende o punto de vista da economía circular, e máis tendo en conta o potencial económico e o beneficio ambiental derivado do seu aproveitamento empregando procesos ou bioprocesos sostibles. Entre eses subprodutos, atópanse os endoesqueletes/prumas da especie de cefalópodo máis capturada a nivel global, o potón (Dosidicus gigas). De eles, poden obterse quitina e quitosano (compostos de grande interese comercial), xerándose durante a súa produción dous efluentes líquidos cun contido en proteína soluble bastante destacable. Nesta memoria estudouse e confirmouse a viabilidade destes efluentes coma fonte de nitróxeno orgánico (proteínas) en substitución das peptonas comerciais presentes nun medio de cultivo específico (MRS) para o crecemento de lactobacterias probióticas coma o Lactobacillus plantarum e o Leuconostoc mesenteroides, así como noutro caldo (Medio Mariño) empregado habitualmente para o desenrolo de bacterias mariñas probióticas como son a Pseudomonas fluorescens e o Phaeobacter sp. Para isto, realizáronse múltiples fermentacións nos medios alternativos e comerciais, cuantificando a biomasa producida ao longo do tempo de cultivo, así como a produción dos metabolitos máis importantes, e os consumos de proteína soluble e de glicosa a cada tempo de mostraxe. Todo isto levouse ao cabo combinando técnicas microbiolóxicas, analíticas, e cromatográficas, con modelado predictivo das cinéticas de cultivo empregando un modelo matemático non estructurado. Os efluentes amosaron ser (especialmente o derivado da quitina) uns excelentes substratos proteicos asimilables ás peptonas comerciais. Ao comparar entre medios alternativos e comerciais, estimouse unha redución ao redor de 4 veces nos costes de produción de biomasa e de ácido láctico das lactobacterias. Tal mellora aumentou ate as 400 veces no caso da produción de biomasa das bacterias mariñas. Ambos efluentes, poderían formar parte dunha posible formulación comercial ao presentar capacidades nutritivas similares a custes moito máis competitivos.