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In recent decades products of marine origin have been the subject of intense investigation; new substances with pharmacological and nutraceutical properties have been discovered. On the other hand, processes more economical and friendly to the environment to produce biocompounds are needed. One alternative is biorefinery for the production of diverse bioproducts starting from one raw material. Our research group studied Macrocystis pyrifera as source of carbohydrates and phlorotannins, and the conditions for their extraction have been determined. The production of carotenoids from algal carbohydrates and the use of phlorotannins from the brown seaweed as antioxidant and antibacterial compounds were evaluated. The extraction yield of carbohydrate and phlorotannins were 81.02 ± 8.9 and 1.62 ± 0.13%, respectively. Carbohydrates were used for the growth and production of carotenoids by a marine yeast Rhodotorula mucilaginosa. The carotenoid content of the yeast biomass was 427 mg g−1 of dry biomass. Main carotenoids were lycopene (38.4 ± 9.4%), β-carotene (21.8 ± 1.5%), and astaxanthin (1.8 ± 0.3%). The residual fraction was used as fertilizer for the hydroponic cultivation of lettuce obtaining an increase of 28 ± 2.8% in dry weight. Here, we have demonstrated that M. pyrifera can be used to obtain antioxidants/antimicrobials, as nutrient source for the biotechnological production of carotenoids; moreover, the residue can be used as fertilizer.

Aims To evaluate an aqueous extract of Macrocystis pyrifera as a nutrient source for the production of carotenoids by a marine Rhodotorula mucilaginosa isolated from seaweed samples. Materials and results The effect of different culture conditions on the concentration of biomass and total pigments was evaluated using a Box-Behnken experimental design. The seaweed extract contained 15% w w-1 of protein and 20% w w-1 of carbohydrate; the main sugar in this fraction was trehalose (78%). The culture conditions that maximize the total pigment concentration (1·84 ± 0·03 mg l-1 ) were initial pH equal to 7, yeast extract as nitrogen source at a concentration of 4 g l-1 , seaweed extract concentration at 25% v v-1 , incubation performed at 25°C and 150 rev min-1 during 6 days. Under optimal growth conditions, three carotenoids were identified among the pigments produced by R. mucilaginosa, lycopene (38·4 ± 9·4%), β-carotene (21·8 ± 1·5%) and astaxanthin (1·8 ± 0·3%). Conclusions Carotenoids of commercial interest (lycopene, β-carotene and astaxanthin) can be produced using a marine R. mucilaginosa cultivated with an aqueous extract of M. pyrifera as nutrient source. The total pigment concentration in the culture ranged between 0·82 and 1·84 mg l-1 , and was significantly affected by the concentration of the seaweed extract, and yeast extract. Significance and impact of the study This work demonstrates that M. pyrifera can be used as a nutrient source for the production of carotenoids by the marine yeast.

Oblongichytrium RT2316-13 synthesizes lipids rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The content of these fatty acids in the total lipids depended on growth temperature. Sequencing technology was used in this work to examine the thraustochytrid&rsquo, s response to a decrease in growth temperature from 15 &deg, C to 5 &deg, C. Around 4% (2944) of the genes were differentially expressed (DE) and only a few of the DE genes (533 upregulated, 206 downregulated) had significant matches to those in the SwissProt database. Most of the annotated DE genes were related to cell membrane composition (fatty acids, sterols, phosphatidylinositol), the membrane enzymes linked to cell energetics, and membrane structure (cytoskeletal proteins and enzymes). In RT2316-13, the synthesis of long-chain polyunsaturated fatty acids occurred through &omega, 3- and &omega, 6-pathways. Enzymes of the alternative pathways (&Delta, 8-desaturase and &Delta, 9-elongase) were also expressed. The upregulation of the genes coding for a &Delta, 5-desaturase and a &Delta, 5-elongase involved in the synthesis of EPA and DHA, explained the enrichment of total lipid with these two long-chain fatty acids at the low temperature. This molecular response has the potential to be used for producing microbial lipids with a fatty acids profile similar to that of fish oils.

Total lipids and docosahexaenoic acid (DHA) production by a Chilean isolated thraustochytrid were evaluated under different growth conditions in shake flasks. The analyzed strain was identified as Thraustochytrium striatum according to an 18S rRNA gene sequence analysis. The strain (T. striatum AL16) showed negligible growth in media prepared with artificial seawater at concentrations lower than 50% v/v and pH lower than 5. Maltose and starch were better carbon sources for growth than glucose. DHA content of the biomass grown with maltose (60 g L−1) was doubled by increasing the agitation rate from 150 to 250 rpm. The DHA (0.8–6%) and eicosapentaenoic acid (0.2–21%) content in the total lipids varied depending on culture conditions and culture age. Lipid and DHA concentration increased (up to 5 g L−1 and 66 mg L−1, respectively) by regularly feeding the culture with a concentrated starch solution. Carotenoid accumulation was detected in cells grown with maltose or starch. Contrasting conditions of starch and glucose cultures were selected for comparative proteomics. Total protein extracts were separated by two-dimensional gel electrophoresis; 25 spots were identified using ESI-MS/MS. A protein database (143,006 entries) for proteomic interrogation was generated using de novo assembling of Thraustochytrium sp. LLF1b – MMETSP0199_2 transcriptome; 18 proteins differentially expressed were identified. Three ATP synthases were differentially accumulated in cultures with glucose, whereas malate dehydrogenase was more abundant in cells cultured with starch.

Production of biomass and lipids in batch cultures of the Antarctic thraustochytrid Oblongichytrium sp. RT2316-13, is reported. The microorganism proved capable of producing nearly 67% docosahexaenoic acid (DHA) and 15% eicosapentaenoic acid (EPA) in its total lipid fraction. Biomass with a maximum total lipid content of 33.5% (wt/wt) could be produced at 15°C in batch culture using a medium containing glucose (20 g/L), yeast extract (10.5 g/L), and other minor components. A lower culture temperature (5°C) reduced biomass and lipid productivities compared to culture at 15°C, but enhanced the DHA and EPA content of the lipids by 6.4- and 3.3-fold, respectively. Both a simple minimally structured mathematical model and a more complex genome-scale metabolic model (GEM) allowed the fermentation profiles in batch cultures to be satisfactorily simulated, but the GEM provided much greater insight in the biochemical and physiological phenomena underlying the observed behavior. Unlike the simpler model, the GEM could be interrogated for the possible effects of various external factors such as oxygen supply, on the expected outcomes. In silico predictions of oxygen effects were consistent with literature observations for DHA producing thraustochytrids.

Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and carotenoids are needed as human dietary supplements and are essential components in commercial feeds for the production of aquacultured seafood. Microorganisms such as thraustochytrids are potential natural sources of these compounds. This research reports on the lipid and carotenoid production capacity of thraustochytrids that were isolated from coastal waters of Antarctica. Of the 22 isolates, 21 produced lipids containing EPA+DHA, and the amount of these fatty acids exceeded 20% of the total fatty acids in 12 isolates. Ten isolates were shown to produce carotenoids (27.4–63.9 μg/g dry biomass). The isolate RT2316-16, identified as Thraustochytrium sp., was the best producer of biomass (7.2 g/L in five days) rich in carotenoids (63.9 μg/g) and, therefore, became the focus of this investigation. The main carotenoids in RT2316-16 were β-carotene and canthaxanthin. The content of EPA+DHA in the total lipids (34 ± 3% w/w in dry biomass) depended on the stage of growth of RT2316-16. Lipid and carotenoid content of the biomass and its concentration could be enhanced by modifying the composition of the culture medium. The estimated genome size of RT2316-16 was 44 Mb. Of the 5656 genes predicted from the genome, 4559 were annotated. These included genes of most of the enzymes in the elongation and desaturation pathway of synthesis of ω-3 polyunsaturated fatty acids. Carotenoid precursors in RT2316-16 were synthesized through the mevalonate pathway. A β-carotene synthase gene, with a different domain organization compared to the gene in other thraustochytrids, explained the carotenoid profile of RT2316-16.

The incentives for utilizing a versatile range of renewable feedstocks in novel ways are continuously increasing. Sulfated polysaccharides from green algae, such as ulvan, are interesting due to th ...

Thraustochytrids have been isolated from different aquatic systems; however, few studies have reported their occurrence in Antarctica. In this study, 13 strains close to strains belonging to the genera Oblongichytrium, Thraustochytrium, and Aurantiochytrium were isolated from seawater samples collected near the Antarctic Base Professor Julio Escudero (S 62°12′57′ E 58°57′35″). Docosahexaenoic acid (DHA) was found in the total lipids of all the isolates; DHA content of the biomass (dry weight) varied between 3.3 and 33 mg/g under the growth conditions for isolation. Five of the Antarctic thraustochytrids were able to accumulate lipids at levels higher than 20% w/w. Two strains, RT2316‐7 and RT2316‐13, were selected to test the effect of the incubation temperature (at 5°C for 14 days and at 15°C for 5 days). Incubation temperature had little effect on the lipid content and biomass yield; however, its effect on the fatty acid composition was significant (p, Marine thraustochytrids are large‐celled oleaginous microorganisms known for their ability to produce docosahexaenoic (DHA) and eicosapentaenoic (EPA) ω‐3‐fatty acids. In this work, strains close to members of the genera Oblongichytrium, Thraustochytrium, and Aurantiochytrium were isolated from seawater samples collected in the Antarctic. DHA was found in the total lipids of all the isolates; DHA content of the biomass (dry weight) varied between 3.3 and 33 mg/g under the growth conditions for isolation. Temperature had little effect on the lipid content and biomass yield; however, its effect on the fatty acid composition was significant. The incubation at 5°C increased the percentage of EPA and omega‐6 fatty acid dihomo‐γ‐linolenic acid (DGLA) of total fatty acids in the strains RT2316‐7 and RT2316‐13, respectively. These strains are promising candidates for the biotechnological production of lipids.

Production of docosahexasaenoic acid (DHA) by a native Labyrinthulomycetes strain, Thraustochytriidae sp. TN5, whose growth characteristics present some differences to related strains, was scaled from shaken flask to a laboratory fermentor. The effect of the growth medium composition and growth conditions for (i) biomass production, (ii) lipid content of the biomass, and (iii) DHA content in the lipids was determined. Taguchi's design of experiments was used to study the influence of two discrete – carbon and nitrogen sources – and six continuous – concentrations of the carbon and nitrogen sources, yeast extract and artificial seawater, incubation temperature, and time- factors on the three mentioned variables. In the flask experiments the lipidic content in the biomass (25.2% w/w) and DHA concentration (0.48 g/L) were the highest at the following conditions: maltose 20 g/L, sodium glutamate 2.4 g/L, yeast extract 6 g/L, 72 h, 25°C, and artificial seawater 30% v/v; under these conditions biomass concentration was 5.1 g/L. Fed-batch allowed to increase biomass concentration to 14 g/L. The lipidic fraction of Thraustochytriidae sp. TN5 biomass in the repeated batches was found between 16.2 and 34.8% w/w. Under this growth condition lipids and DHA productivities were 50 and 23 mg/(L h), respectively. Practical applications: Consumption of long chain-polyunsaturated fatty acids (LC-PUFA) belonging to the omega-3 family such as DHA has several positive effects on human and animal health. However, natural sources are restricted to cold-water fish and their oils. Marine protists are also good candidates for the production of microbial DHA. For evaluating the potential of new strains the effect of the growth medium composition, growth conditions, and cultivation mode on DHA productivity has to be determined. In this work the production of DHA by a native Labyrinthulomycetes strain was scaled from shaken flask to a laboratory fermentor with the aid of Taguchi's methodology, process in which biomass concentration, lipid content in the biomass, and DHA content in the lipids were increased.

The effect of 8 factors [(with/without) daily mixing and moisture control, incubation time (t), temperature, ratio between dry substrate mass and bed’s cross section area (MA), inoculum size (spores/g), wheat germ content (WG), initial pH, and moisture content (M)] in the production of a prolyl endopeptidase (PEP) by Aspergillus niger ATCC 11414 in solid state fermentation (SSF) was tested. Contribution of all the factors was significant (p

The effect of extrusion of soybean (Glycine max), yellow lupin (Lupinus luteus), and linseed (Linum usitatissimum) on the activity of porcine pancreatic lipase (PPL) was evaluated through pH-Stat methodology with tributyrin emulsions in which the seed meals [extruded (E) and non-extruded (NE)] were dispersed. The seed meals affected PPL activity in a concentration-dependent fashion; at 2.3 mg/mL the meals reduced PPL activity (11.7–45.0% reduction) while the opposite was true (3.1–28.0% increase) at 6.8 mg/mL. PPL activity in the assays containing E-lupin, E-soybean and E-linseed meals at 2.3 mg/mL was 109.7 and 11.3% higher and 25.5% lower than the activity in the emulsions containing the NE-meals, respectively. The differences between the PPL activity in emulsions containing the extruded and NE-meals could be due to changes in the emulsifying properties of the meals after extrusion; extrusion increased (10.2%) the emulsification capacity of lupin meal and for linseed meal this property was reduced (9.2%). In spite of the low PPL activity at low meal concentrations, the percentage of free fatty acids released after 30 min was similar to the theoretical maximum (66.6%) with two exceptions – NE-soybean meal (59.5 ± 2.7%) and E-linseed meal (57.9 ± 1.2%). Practical applications: Feed and food industries use plant protein sources that contain inhibitors of digestive enzymes. Various proteases inhibitors are inactivated during extrusion being less known the effect of extrusion on lipase inhibitors. Reduction of lypolysis rate, carried out mainly by pancreatic lipase in human and other animals, could influence feed and food consumption because satiety is controlled – at least in part – by undigested lipids. Our results show that extrusion can be used to reduce the inhibitory activity of lupin and soybean on PPL. On the other hand, extrusion of linseed increased the negative effect of this meal on PPL activity effect that could have applications in the development of food and ingredients for weight control.

Thraustochytrids are marine protists found throughout the world in estuarine and marine habitats. These microorganisms have attracted interest, because their lipids contain different long chain polyunsaturated fatty acids (PUFAs). Those able to produce docosahexaenoic acid (C22:6 n-3, DHA) are the most studied because of the physiological importance of this PUFA in human beings. Their heterotrophic cultivation offers several challenges since biomass, lipid content, and fatty acid profile are dependent on growth conditions. In this work the effects of C source and its concentration on DHA production by different thraustochytrid strains are reviewed. Results obtained by different investigators on the use of alternative and low cost nutrient sources for production of DHA by thraustochytrids are also presented.