Marine fungoid producers of DHA, EPA and carotenoids from central and southern Chilean marine ecosystems

Abstract

Resumen.-La creciente demanda de ácidos grasos poliinsaturados (AGPI) provocada por la escasez de pesca extractiva, ha impulsado la obtención de fuentes alternativas sustentables para abastecer su mercado. Los Thraus tochytridos y levaduras marinas (fungoides marinos), son potenciales productores de lípidos y carotenoides de importancia comercial. Desde una colección de 41 cepas de fungoides marinos aisladas en el Sistema de Corriente de Humboldt, se determinó la capacidad de producir DHA (ácido docosahexanoico), EPA (ácido eicosapentanoico) y CT (carotenoides totales) en cultivos líquidos comercial (MS) y alternativos (PDB, GAM, BAM y MCM). Los resultados indican que el medio MS y PDB, presentaron las mayores velocidades de crecimiento (0,02 h -1 ). No obstante, el medio MS presenta estos parámetros cinéticos a 16ºC y el PDB a 37°C. Trece de las cepas analizadas presentaron una alta capacidad para producir DHA (hasta 23% peso seco) y CT (hasta 18% peso seco), comparables a los niveles observados en Schizochytrium sp. KH105 y Rhodosporidium toruloides. Adicionalmente, todas las cepas ensayadas también produjeron pequeñas cantidades de EPA (hasta 0,3% peso seco). La microscopia electrónica revela que la cepa C36 es morfológicamente consistente con levaduras y su secuencia parcial del gen ribosomal 18s presenta un 97% de similitud con el género Rhodotorula, el que hasta ahora no ha sido reportado como productor de DHA y EPA. Finalmente, las cepas C36, C22 y C4 son interesantes objetos de estudio para escalar su producción y proyectar su uso comercial, como por ejemplo para suplementar en omega-3 y carotenoides alimentos para consumo humano, animales de corral o para estadios larvales de peces cultivados y pigmentar la carne del salmón, entre otros.Palabras clave: Fungoides marinos, DHA, EPA, carotenoides totales, Rhodotorula, parámetros cinéticos Abstract.-Declining fishing yields have pushed the search for sustainable alternative sources for polyunsatura ted fatty acids (PUFAs). Thraustochytrids and marine yeasts (marine fungoid protists) are potential commercial sources of lipids and carotenoids. It was determined the capacity of a collection of 41 strains of marine fungoid isol ated in the Humboldt Current System, to produce DHA (docosahexanoic acid), EPA (eicosapentanoic acid) and CT (total carotenoids) in commercial growing media (MS) and alternative growing mediums (PDB, GAM, BAM and MCM). The media MS and PDB exhibited the highest growth rate (0.02 h -1 ), at 16 and 37°C, respectively. Thirteen of the studied strains showed high capacity to produce DHA (up to 23% dry weight) and CT (up to 18% dry weight), comparable to levels observed in Schizochytrium sp. KH105 and Rhodosporidium toruloides. Additionally, all studied strains produce small amounts of EPA (up to 0.3% of dry weight). Scanning electron microscopy reveals that strain C36 is morphologically consistent with yeasts, while partial sequencing of the 18s ribosomal gene shows 97% similarity to the genus Rhodotorula, which has not been reported until n...

The Marine Fungi Rhodotorula sp. (Strain CNYC4007) as a Potential Feed Source for Fish Larvae Nutrition

“…The present work studied the effect of the strain CNYC4007 of the marine basidiomycete Rhodotorula sp. [ 27 ] in the RNA/DNA ratio, which was used as a proxy for the nutritional state of Danio rerio larvae. The larvae were fed in their different stages of development and the strain was administered in three forms (flour, microencapsulated, and bioencapsulated).…”

“…The strain used in this study has a 97% identity for the gene 18S ribosomal RNA (rRNA) of Rhodotorula sp. [ 27 ]. It was extracted from Caleta Maule, Biobío Region, Chile, and is stored in the National Collection of Yeast Cultures in the UK with the code CNYC4007.…”

“…The mobile phase consisted of a flow of 1 mL per min −1 of gradient A (25% acetonitrile), to 50% of gradient B (100% acetonitrile), with a flow of 2 mL per min −1 for the first 15 min and then 1 mL per min −1 for another 15 min. DHA and EPA were identified through the construction of their respective calibration curves using HPLC grade standards (Sigma-Aldrich ® , Darmstadt, Germany) with an injection volume of 10 µL [ 27 ].…”

“…Another alternative to fish oil is single-cell oils (SCO) from one-cell organisms like bacteria, algae, fungoid protists and marine fungi, which have great potential because of their high essential long-chain unsaturated fatty acid content [ 25 , 26 ]. Marine fungi has also been described as producers of carotenoids, omega-3 fatty acids, including DHA and EPA [ 27 ], and omega-6 acids like arachidonic acid (20:04 ω6, AA) [ 28 ].…”

“…(CNYC4007) from the Humboldt Current System off Central Chile was isolated and grown in a bioreactor. The strain, which has high levels of DHA, EPA and carotenoids [ 27 ], could be considered as a suitable source of omega-3 for the aquaculture demand. In reference to the above the aim of this study was to evaluate the use of strain CNYC4007 for feeding Danio rerio larvae.…”