Selenium Biotransformations in an Engineered Aquatic Ecosystem for Bioremediation of Agricultural Wastewater via Brine Shrimp Production

An engineered aquatic ecosystem was specifically designed to bioremediate selenium (Se), occurring as oxidized inorganic selenate from hypersalinized agricultural drainage water while producing brine shrimp enriched in organic Se and omega-3 and omega-6 fatty acids for use in value added nutraceutical food supplements. Selenate was successfully bioremediated by microalgal metabolism into organic Se (seleno-amino acids) and partially removed via gaseous volatile Se formation. Furthermore, filterfeeding brine shrimp that accumulated this organic Se were removed by net harvest. Thriving in this engineered pond system, brine shrimp (Artemia franciscana Kellogg) and brine fly (Ephydridae sp.) have major ecological relevance as important food sources for large populations of waterfowl, breeding, and migratory shore birds. This aquatic ecosystem was an ideal model for study because it mimics trophic interactions in a Se polluted wetland. Inorganic selenate in drainage water was metabolized differently in microalgae, bacteria, and diatoms where it was accumulated and reduced into various inorganic forms (selenite, selenide, or elemental Se) or partially incorporated into organic Se mainly as selenomethionine. Brine shrimp and brine fly larva then bioaccumulated Se from ingesting aquatic microorganisms and further metabolized Se predominately into organic Se forms. Importantly, adult brine flies, which hatched from aquatic larva, bioaccumulated the highest Se concentrations of all organisms tested

Nutrigenomics and immune function in fish : new insights from omics technologies

This study was funded by BBSRC grant BB/M026604/1.Peer reviewedPublisher PD

Chlorella vulgaris biomass enriched by biosorption of polyphenols

Cell walls of microalgae are variable and contain non-specific domains where different molecules can bind. The enrichment of microalgal biomass with nutrients through adsorption can be an interesting process for the food and feed industry. In this study, naturally occurring polyphenols ((+)-catechin, ()-epicatechin, quercetin, rutin and xanthohumol) were adsorbed onto nonliving cells of freshwater microalgae Chlorella vulgaris. The essential adsorption parameters such as biomass dose and contact time were examined and the adsorption was quantified with Langmuir, Sips and DubininRadushkevich adsorption isotherms. The evaluation of isotherms proved the highest affinity towards Chlorella vulgaris biomass for xanthohumol and quercetin. The biosorption mechanism of Chlorella vulgaris biomass was well described by a pseudo second order kinetic model, with a high regression coefficient. The polyphenol-enriched microalgal biomass was also evaluated for its antioxidant activity. The highest antioxidant activity was detected in the case of biomass enriched with quercetin (77.5% of decolorized DPPH).The financial support by the Ministry of Education, Youth and Sports of the Czech Republic through grant MSM6046137305 is gratefully acknowledged. Cristina Quintelas is thankful to Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for funding the CEB researcher unit at the University of Minho and thanks the Project "BioInd - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte), QREN and FEDER

Accumulation and elimination dynamics of the hydroxybenzoate saxitoxin analogues in mussels Mytilus galloprovincialis exposed to the toxic marine Dinoflagellate Gymnodinium catenatum

Paralytic shellfish poisoning (PSP) is a severe food-borne illness, caused by the ingestion of seafood containing paralytic shellfish toxins (PST), which are naturally produced by marine dinoflagellates and accumulate in shellfish during algae blooms. Novel PST, designated as hydroxybenzoate analogues (also known as GC toxins), was relatively recently discovered in Gymnodinium catenatum strains worldwide. However, to date, there have been no studies examining their accumulation in shellfish. In this study, mussels (Mytilus galloprovincialis) were exposed to G. catenatum for five days and then exposed to a non-toxic diet for 24 h, to investigate the toxin's accumulation/elimination dynamics. As determined by UHPLC-HILIC-MS/MS, the hydroxybenzoate analogues, GC1 to GC6, comprised 41% of the algae toxin profile and only 9% in mussels. Elimination of GC toxins after 24 h was not evident. This study highlights that a relevant fraction of PST in mussels are not routinely analysed in monitoring programs and that there is a need to better understand the toxicological potential of the hydroxybenzoate analogues, in order to properly address the risk of G. catenatum blooms.Centre for Environment, Fisheries and Aquaculture Science - contract code DP402; Fundacao para a Ciencia e a Tecnologia - PD/BD/113484/2015; FCT Investigator; Mar2020 - SNMB-INOV: Innovation for a more competitive shellfish sector, co-financed by the Operational Program Mar 2020, Portugal 2020info:eu-repo/semantics/publishedVersio

Algae as nutritional and functional food sources: revisiting our understanding.

Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.AGS & KEH thank the Biotechnology and Biological Sciences Research Council (BBSRC BB/1013164/1) of the UK for funding. The University of Dundee is a registered Scottish charity, No. SC015096. PP is supported by IDEALG in the frame of the stimuli program entitled “Investissements d’avenir, Biotechnologies-Bioressources” (ANR-10-BTBR-04-02). The open access fee was supported by NSF-OCE-1435021 (MLW), DIC project 1823-06 (MEC), Maine Sea Grant (NOAA) 5405971 (SHB), NSF #11A-1355457 to Maine EPSCoR at the University of Maine (SHB), and the listed funding to AGS and PP

Fishmeal replacement with Spirulina Platensis and Chlorella vulgaris in African catfish (Clarias gariepinus) diet: Effect on antioxidant enzyme activities and haematological parameters

This study explored fishmeal replacement with two freshwater microalgae: Spirulina Platensis and Chlorella vulgaris in African catfish (Clarias gariepinus) diet. The effect of inclusion of the two microalgae on biomarkers of oxidative stress, haematological parameters, enzyme activities and growth performance were investigated. The juvenile fish were given 3 distinct treatments with isonitrogenous (35.01–36.57%) and isoenergetic (417.24–422.27 Kcal 100 g−1) diets containing 50% S. platensis (50SP), 75% S. platensis (75SP), 50% C. vulgaris (50CL), 75% C. vulgaris (75CL) and 100% fishmeal (100% FM) was used as the control diet. The result shows that all the diets substituted with both S. platensis, and C. vulgaris boosted the growth performance based on specific growth rate (SGR) and body weight gain (BDWG) when compared with the control diet. The feed conversion ratio (FCR) and protein efficiency ratio (PER) was significantly influenced by all the supplementations. The haematological analysis of the fish shows a significant increase in the value of red and white blood cells upon supplementation with 50SP and 50CL but decrease slightly when increased to 75SP and 75CL. Furthermore, the value of haematocrit and haemoglobin also increased upon supplementation with 50SP and 50CL but decrease slightly when increased to 75SP and 75CL. The white blood cell (WBC), red blood cell (RBC) increased, while total cholesterol (TCL), and Plasma glucose levels decreased significantly upon supplementation of algae. This is a clear indication that S. platensis and C. vulgaris are a promising replacement for fishmeal, which is a source protein in the C. gariepinus diet