Search

[Purpose] This study investigated the effects of marine phytoplankton supplementation (Oceanix®, Tetraselmis chuii ) on 1) maximal isometric strength and immune function in healthy humans following a one-week high-intensity resistance-training program and 2) the proinflammatory cytokine response to exercise in a rat model. [Methods] In the human trial, 22 healthy male and female participants were randomly divided into marine phytoplankton and placebo groups. Following baseline testing, participants underwent a 14-day supplement loading phase before completing five consecutive days of intense resistance training. In the rat model, rats were randomly divided into four groups (n=7 per condi tion): (i) control, (ii) exercise, (iii) exercise + marine phy toplankton (2.55 mg/kg/day), or (iv) exercise + marine phytoplankton (5.1 mg/kg/day). Rats in the exercising groups performed treadmill exercise 5 days per week for 6 weeks. [Results] In the human model, marine phytoplankton prevented significant declines in the isometric peak rate of force development compared to placebo. Additional ly, salivary immunoglobulin A concentration was signifi cantly lower following the resistance training protocol in the placebo group but not in the marine phytoplankton group. Marine phytoplankton in exercising rats de creased intramuscular levels and serum concentrations of tumor necrosis factor-alpha (TNF-α) and interleu kin-1 beta (IL-1β) and intramuscular concentrations of malondialdehyde. [Conclusion] Marine phytoplankton prevented dec rements in indices of functional exercise recovery and immune function. Mechanistically, these outcomes could be prompted by modulating the oxidative stress and proinflammatory cytokine response to exercise.

Microalgal biomass has been widely reported as feed, biodiesel, and pigment source. Species with high concentration of protein, easy to commercial culture and faster growth rates are the preliminary considerations for the species to be used as animal feed. In this study marine microalgae were isolated from different coastal aqua-farms of Southern Coast of Bangladesh. A total of four species were isolated from different coastal aqua-farms. Among the four identified species three species were green microalgae ( Chlorella sp., Nannochloropsis sp., and Tetraselmis sp.) and one was brown microalgae ( Chaetoceros sp.). Growth curves, productivity and proximate composition of identified microalgae were determined to observe the growth rates and nutritional profile. It was found that Nannochloropsis sp. is the most potential species considering its complete profile. Moreover, Chlorella sp. and Tetraselmis sp. are also found suitable. These species are potential candidates as animal feedstuffs considering mainly their protein profile.

Phytoplankton occupies a key trophic level in aquatic ecosystems. Chemical impacts on these primary producers can disrupt the integrity of an entire ecosystem. Two freshwater (Pseudokirchneriella subcapitata-Ps and Scenedesmus obliquus-S) and three marine (Phaeodactylum tricornutum-P, Isochrysis galbana-I, Tetraselmis suecica-T) microalgae species were exposed to dilutions of four chemicals: nanoparticles (n-TiO2, n-ZnO), amoxicillin (antibiotic), and white musk (personal care fragrance) to determine the half maximal effective concentration (EC50) after 72 h of exposure under standardized and controlled environmental conditions. Cell cultures were exposed to EC50 to determine sublethal effects (72 h) based on biochemical (chlorophylls a, b, c), molecular (changes in outer cell wall structure), and morphological alterations. We report for the first time EC50 values for nanoparticles in not standardized species (S, I and T) and for amoxicillin and white musk in all tested species. Standardized species (Ps and P) were less sensitive than non-standardized in some cases. Fourier-transformed infrared spectroscopy showed a marked spectral alteration (from 10.44% to 90.93%) of treated cultures compared to negative controls; however, principal component analysis disclosed no differences in molecular alteration between the five microalgae species or the two aquatic habitats considered. There was a significant decrease in chlorophylls content in all species exposed to EC50 compared to controls (Kruskal Wallis test; p < 0.05). There was a significant increase in cell-size (Mann–Whitney U test; p < 0.05) in I, P and T exposed to white musk and S exposed to amoxicillin. Findings highlight ecotoxicological risks from new generation pollutants for primary producers in aquatic ecosystems.

The increasing instability of climate dynamics, caused by pervasive anthropogenic pressures, demands profound ecosystem management through environmental protection and sustainable development. The most widely used environmental indicator for monitoring climate change is temperature, while heavy metals such as cadmium reflect anthropogenic activities. Nowadays, there is a high need to use a parameter for direct and high-throughput analysis of the behavior of intact cells in aquatic samples. This study aims to investigate the potential of cell motility as a direct indicator of environmental stress using two flagellated green algae that differ in cell barrier and flagellar system morphology. The open- source image processing software was used to quantitatively characterize changes in motility behavior in terms of swimming speed and search radius based on video data acquisition. The results showed that the change in growth temperature from favorable conditions caused a decrease in swimming speed and search radius of the two green algae studied. Moreover, the presence of heavy metal cadmium in the growth medium caused a decrease in the swimming speed and search radius of species possessing a soft cell envelope in contrast to specie with a rigid cell envelope. Thus, the response of algae to stressors in batch culture appears to be species-specific, with cell morphology contributing to stress tolerance. Algal cells with soft glycocalyx membranes appear to be more sensitive to temperature and heavy metals than cells encased in a stiffer calcite theca. Concurrent studies revealed concomitant changes in algal cell surface properties and physiological activity when exposed to the corresponding stressors, which contributes to the understanding of motility behavior at the single-cell level. Based on the presented results, the changes in algal motility may be used to indicate disturbances in the aquatic system and serve for monitoring needs.

To develop greener extraction alternatives for microalgae biomass, ultrasound assisted extraction (UAE) and pressurized liquid extraction (PLE) with different biobased solvents were investigated, demonstrating that both techniques are useful alternatives for algal lipid extraction. Specifically, Nannochloropsis gaditana lipids were extracted by UAE and PLE at different temperatures and extraction times with sustainable solvents like 2-Methyltetrahydrofuran (2-MeTHF) and its mixtures with ethanol and other alcohols. The best oil yields for both PLE and UAE of N. gaditana were achieved with the mixture of 2-MeTHF:ethanol (1:3), reaching yields of up to 16.3%, for UAE at 50 °C and up to 46.1% for PLE at 120 °C. Lipid composition of the extracts was analyzed by HPLC-ELSD and by GC-MS to determine lipid species and fatty acid profile, respectively. Different fractionation of lipid species was achieved with PLE and solvent mixtures of different polarity. Thus, for the extraction of glycolipids, ethanolic extracts contained higher amounts of glycolipids and EPA, probably due to the higher polarity of the solvent. The optimized method was applied to microalgae Isochrysis galbana and Tetraselmis chuii showing the potential of mixtures of biobased solvents like 2-methyl-THF and ethanol in different proportions to efficiently extract and fractionate lipids from microalgal biomass.

The aim of this paper was to develop high-protein vegetable creams through the incorporation of microalgae. Single-cell ingredients from Arthrospiraplatensis (spirulina), Chlorella vulgaris, Tetraselmis chui, and Nannochloropsis oceanica were incorporated at two levels of addition (1.5% and 3.0%) to a standard vegetable cream (STD). Effects of incorporation were assessed in terms of physicochemical and rheological attributes as well as nutritional labeling facts. Creams formulated with 3% A. platensis, N. oceanica, or T. chui showed strong color differences (6 < ΔE < 12) compared to STD; creams formulated with 1.5% A. platensis, T. chui, or N. oceanica showed perceptible differences (3 < ΔE < 6); and those made with C. vulgaris at 1.5 and 3% exhibited small differences (ΔE < 2). Moisture content, water activity, pH, syneresis, and °Brix did not show significant changes. Adding microalgae increased Bostwick consistency and decreased the consistency coefficient (K) except in creams made with A. platensis, which showed comparable values to STD. Principal component analysis indicated that creams made with 1.5% C. vulgaris were the most similar to STD considering all evaluated parameters. Estimation of the nutritional labeling facts showed that the four formulations could be labeled as having “high protein content” following the present EU legislation.

Three species of microalgae were used in this study, namely Nitzschia sp., Porphyridium sp., and Tetraselmis sp., which collected from the Lampung Agency of Maricultures – Ministry of Coastal and Marine Affairs. They were cultured in room temperature with 12:12 day light and given different salinities and pH for treatment groups with complete randomized design. Nitzschia sp. and Porphyridium sp. were treated within factorial design 2x2, namely 20 and 40 ppt in salinities and 5 and 10 in pH, while the Tetraselmis sp. was given with factorial 3x3, namely 10, 15, 20 ppt of salinities and 5, 8, 9.5 in pH. All the cultures for 7 days were replicated 3 times. Analysis of variance followed by LSD at 5% level of significant was applied to analyse the data on specific growth rate and total lipid contains. The results indicated that highest growth rate of Nitzschia sp. was in 20 ppt of salinity and at pH of 10, while Porphyridium sp. was in 40 ppt salinity and at pH of 5. But the highest lipid content of Nitzschia sp. was in 40 ppt of salinity with 5 pH, and Porphyridium sp. was in 40 ppt of salinity and 5 in pH. Tetraselmis sp. had the highest growth rate in 20 ppt of salinity and at pH of 9.5, but the highest total lipid of it was in 10 ppt of salinity with 9.5 pH. Keywords: Nitzschia sp., Porphyridium sp., Tetraselmis sp., lipid, salinity, pH

Powdered biomass of Nannochloropsis sp. and Tetraselmis sp. were used as innovative ingredients in wheat tortillas at flour substitution levels of 0.5–3.0%. Incorporation of microalgae into the tortilla formulations led to increased protein and fat content. The content of phenolic and carotenoids was also higher in microalgae-enriched tortillas, especially for those enriched in Nannochloropsis sp. at a flour substitution level of 3.0%. Not only the phenolic content but also the antioxidant capacity of the tortillas was higher after microalgae incorporation. Bioaccessible polyphenols were also higher in microalgae-containing tortillas as well as the antioxidant capacity of the enzymatic digestive extracts. No major differences in physical parameters (besides colour) were observed, and the overall acceptance of the microalgae-enriched tortillas assessed after a sensorial analysis was comparable to that of the wheat-only controls. Moreover, the purchase intention of the products as well as the acceptability index suggested that the tortillas would have a good acceptance. Several reports highlighted the nutritional value of microalgae. The production of microalgae and their utilisation as novel ingredients in innovative foods will increase the sustainability of the food industry and promote health. info:eu-repo/semantics/acceptedVersion

Currently, microalgae have begun to be explored extensively as potential feedstock for renewable fuel production. To transform microalgae into liquid fuel, hydrothermal liquefaction (HTL) process is proposed. In this study, HTL process was conducted without catalyst in controlled high pressure batch reactor. The effect of reaction temperature (200 and 225 °C) and time (10-30 minutes with interval of 10 minutes) of HTL process on the products (bio-crude oil, biochar, water-phase liquid and gaseous) was investigated. Microalgae Tetraselmis chuii studied in this HTL process was characterized in low lipid condition. The bio-crude oil yield of 0.77% was the maximum value, reached at temperature of 225 °C and reaction time of 30 minutes. In this experimental condition, the lowest product was obtained for biochar and water-phase liquid. On the contrary, the increasing temperature and reaction time led process to produce more gaseous phase hydrocarbon.

The aim of this work was to investigate the potential of cell motility as a direct indicator of environmental stress (temperature change, heavy metal presence).

In this study, marine microalgae were isolated from the Bay of Bengal, and their biodiesel production potential was investigated. Five different strains of microalgae were identified, viz. Nannochloropsis salina (N. salina), Dunaliella salina (D. salina), Chaetoceros calcitrans (C. calcitrans), Tetraselmis chuii (T. chuii), and Euglena sanguinea (E. sanguinea). Further, these stains were mass cultivated in a 250-L bioreactor to assess their biomass production ability. At the end of the exponential phase, algal biomass was harvested for lipid extraction. The fatty acid profile and physico-chemical properties of the lipids were analyzed. It was observed that a maximum of 27.67wt% of lipid was obtained for N. salina followed by D. salina (22.58 wt%), E. sanguinea (21.88 wt%), T. chuii (20.15 wt%), and C. calcitrans (16.25 wt%). Subsequently, the extracted lipids were subjected to single-step esterification and transesterification process to produce biodiesel by using an acid catalyst. The different parameters influencing the reaction such as catalyst concentration, temperature, methanol to lipid molar ratio, and time were investigated. A maximum biodiesel yield of 97, 94, 96, 92, and 92 wt% were obtained for N. salina, D. salina, C. calcitrans, T. chuii, and E. sanguinea, respectively, at the favorable reaction conditions. The fuel properties of biodiesel were analyzed as per the standard protocol and compared with ASTM D6751 standard.

The environmental effects of nanoplastics-NPLs have been addressed mainly through short-term exposures to a few types of polymers, neglecting other NPLs that are economically relevant like polymethylmethacrylate - PMMA. This work aimed to assess long-term effects of PMMA-NPLs on the marine primary consumer Brachionus plicatilis, evaluating the influence of different exposure routes (waterborne, foodborne and both) and food items (Nannochloropsis gaditana and Tetraselmis chuii). Rotifers were 21 days exposed to: a) control, with clean medium and food-CTR; b) contaminated medium (8.1 mg PMMA-NPLs/L) and clean algae-MC; c) clean medium and contaminated algae (pre-incubated for 96 h on 8.1 mg PMMA-NPLs/L)-AC; and, d) contaminated medium and algae–MC/AC. Mortality (lx), total number of organisms (TN), fecundity (mx), populational growth rate (r), generational time (gt), and feeding rates were assessed. Effects on r and mx were found after 21 days. Organisms from AC had higher r than MC. MC/AC organisms performed better than control in all endpoints. Overall organisms fed with N. gaditana had higher TN, mx and r than those fed with T. chuii. In the AC treatments, rotifers fed with N. gaditana had higher mx. Results highlight that exposure route and food type may modulate NPLs’ effects, supporting the need for standardization of assays.

The biofiltration capacity of bivalve populations is known to alleviate the effects of coastal eutrophication. However, this important ecosystem service could potentially be impaired by the increasing microplastic abundance in near shore environments. It is known that relatively large microplastics (∼500 μm) impair the filtration capacity of bivalves, however, the effect of smaller microplastics, and specifically microfibers, is not known even though they are more common in many natural systems and similar in size to phytoplankton, the main food source of mussels. Here, we investigated the effects of long-term exposure to microfibers (MFs), which are smaller than 100 μm, on the biofiltration capacity of the blue mussel, Mytilus edulis. Our findings show that long-term exposure (here 39 days) to microfibers significantly reduced (21%) the clearance of phytoplankton (Tetraselmis sp). While previous studies have shown that larger microplastics can decrease the filtration capacity of mussels after short-term exposure, our findings suggest that, for smaller MFs, mussel's clearance capacity is significantly affected after long-term exposure (39 days in this study). This may be due to the accumulation of MFs in the digestive system. In addition, the most efficient phytoplankton consumers were more susceptible to MF accumulation in the digestive system. This suggests that prolonged exposure to MF of coastal mussels could negatively impact the biofiltration of more potent individuals, thus decreasing the ecosystem service potential of the population as a whole.

The suitable culture condition for specific microalgae species is vitally important for their optimal growth and biochemical production. Therefore, this study emphasized on the isolation and screening of indigenous microalgae species with high growth performance from Setiu wetlands, Terengganu, Malaysia. Successfully isolated microalgae were identified based on morphological and molecular approaches using 18S rDNA technique. Microalgae were screened to identify their species with high growth performance based on optical density and Nile red fluorescence dye. Further, the effect of different salinity towards the growth performance of isolated microalgae and proximate composition including protein, lipid, and carbohydrate were identified. Out of nine microalgae strain, three species of indigenous microalgae were successfully isolated and identified known as Chlorella vulgaris, Tetraselmis chuii, and Isochrysis galbana during 16 days of culture period. The highest optical density was found in C. vulgaris, T. chuii, and I. galbana with 1.228 ± 0.039 a.u, 0.758 ± 0.024 a.u and 0.853 ± 0.048 a.u, respectively. Chlorella vulgaris, T. chuii, and I. galbana were also showed the highest specific growth rate with 0.548 μmax/day, 0.686 μmax/day and 0.478 μmax/day, respectively. Using Nile red fluorescent dye screening, C. vulgaris, T. chuii and I. galbana also showed the highest fluorescence intensity of lipid, carotenoid and chlorophyll a content. Based on these criteria, C. vulgaris, T. chuii and I. galbana were selected for further determination on the effect of salinity towards the growth and proximate composition of the selected microalgae. The optimum salinity level of culture medium for T. chuii was 40 ppt with the highest cell density (6.215 × 106 cells/mL; Day 6), protein content (40.47 ± 0.51% of dry weight) and carbohydrate content (42.57 ± 0.83% of dry weight). For I. galbana, 24 ppt was found to be the best culture medium in term of the highest cell density (20.58 × 106 cells/mL; Day 7), and carbohydrate content (29.28 ± 0.47% of dry weight), while lipid content was highest at 40 ppt (15.68 ± 0.58% of dry weight). For C. vulgaris, 10 ppt was the best culture medium in term of the highest cell density (31.17 × 106 cells/mL) and lipid content (13.12 ± 1.12% of dry weight), while carbohydrate and protein content were highest at 0 ppt with 44.53 ± 0.56% and 40.16 ± 2.22% of dry weight, respectively. Overall, the variation of salinity had affected the growth and biochemical compositions of C. vulgaris, T. chuii and I. galbana. Therefore, this study is important for the cultivation of C. vulgaris, T. chuii and I. galbana of different specific target by manipulating the salinity variation of culture medium that can be used as a feed in aquaculture industry.

Estuarine ecosystems near mega-cities are sinks of anthropogenic endocrine disrupting chemicals (EDCs). As the most important primary producer, indigenous microalgae and their secreted extracellular polymeric substances (EPSs) might interact with EDCs and contribute to their fate and risk. Tetraselmis sp. is a representative model of estuarine microalga, for which EDC toxicity and its effects on EPS synthesis have rarely been studied. Through microalgal isolation, algal cell growth tests, EDC removal and the characterization of related EPS profiles, the present work intends to clarify the comparative responses of Tetraselmis sp. to nonylphenol (NP), bisphenol A (BPA) and 17α-ethinylestradiol (EE2). The results showed that the half inhibitory concentration on cell growth was 0.190–0.313 mg/dm3 for NP, which was one order of magnitude lower than the comparable values for BPA and EE2 at 2.072–3.254 mg/dm3. Regarding chlorophyll, NP induced its degradation, EE2 led to its decreased production, and BPA had no obvious effect. Under EDC stress, only the concentrations of colloidal polysaccharides and proteins responded dose-dependently to EE2. Except for the colloidal fraction in the EE2 treatment group, the increase in neutral monosaccharides, especially glucose and galactose, was a common response to EDCs. Compared to the recalcitrant BPA, NP underwent abiotic degradation in alga-free water, and EE2 could be biodegraded in water containing this microalga. The chemical-specific responses of cell growth, chlorophyll and related EPS profiles were driven by the different fates of EDCs, and the underlying mechanism was further discussed. The results obtained in the present work are of critical importance for understanding the fate and effects of different EDCs mediated by microalgae and their related EPSs.

This study aimed to analyse the effects of Tetraselmis chuii (TC) microalgae supplementation during thirty days on ergospirometric, haematological and biochemical parameters in amateur soccer players. Thirty-two amateur soccer players divided into a control group (CG, n = 16, 22.36 &plusmn, 1.36 years, 68.36 &plusmn, 3.53 kg) and a supplemented group (SG, 22.23 &plusmn, 2.19 years, 69.30 &plusmn, 5.56 kg) participated in the double-blind study. SG ingested 200 mg of the TC per day, while CG ingested 200 mg per day of lactose powder. Supplementation was carried out for thirty days. The participants performed a maximal treadmill test until exhaustion. The ergospirometric values at different ventilatory thresholds and haematological values were obtained after the test. Heart rate decreased after supplementation with TC (p &lt, 0.05). Oxygen pulse, relative and absolute maximum oxygen consumption increased in SG (pre vs. post, 19.04 &plusmn, 2.53 vs. 22.08 &plusmn, 2.25, 53.56 &plusmn, 3.26 vs. 56.74 &plusmn, 3.43, 3.72 &plusmn, 0.35 vs. 3.99 &plusmn, 0.25, p &lt, 0.05). Haemoglobin and mean corpuscular haemoglobin increased in SG (pre vs. post, 15.12 &plusmn, 0.87 vs. 16.58 &plusmn, 0.74 p &lt, 0.01, 28.03 &plusmn, 1.57 vs. 30.82 &plusmn, 1.21, 0.05). On the other hand, haematocrit and mean platelet volume decreased in SG (p &lt, 0.05). TC supplementation elicited improvements in ergospirometric and haematological values in amateur soccer players. TC supplementation could be valuable for improving performance in amateur athletes.

The feasibility of use microalgae biotechnology to improve water quality together with the production of biomass to replace fish meal or fish oil in two marine fish farms with different production systems were studied. The samples were taken from a flow-through system (FTS) and a recirculating aquaculture system (RAS) with sea bass cultures of 300 g and 120 g, respectively. The most suitable stream for microalgae cultivation was that from RAS as the concentration of N in the microalgae reactor influent should be ≥8 mg TN L−1 to operate at the same hydraulic retention time than the solids retention time, independently of the productivity of the reactor. Tetraselmis chuii were cultured in 18 L bubble column reactors under batch and semi-continuous operation in media that mimic a RAS stream. The results showed that RAS systems enriched with trace metals generate viable streams for microalgae growth with average biomass productivity under semi-continuous operation of 69 mg TSS L−1 d−1. Nutrients concentrations at the end of the experiment under semi-continuous operation were 0.76 mg TDN L−1 and 0.01 mg TDP L−1, similar to those in the make-up water of the RAS. The composition of microalgae biomass obtained shows that it could be optimal as a substitute for fish meal in sea bass feed.

Prorocentrum lima is a cosmopolitan benthic dinoflagellate capable of producing the diarrhetic shellfish toxins (DSTs) okadaic acid (OA) and dinophysistoxin (DTX). These compounds may cause oxidative stress and accumulate in bivalve tissues, which become vectors of intoxication to human consumers. We investigated DST accumulation, detoxification and oxidative stress biomarkers in clams (Anomalocardia flexuosa) experimentally exposed to P. lima cells or their compounds. Experimental diets consisted of 6000 cells mL-1 of the non-toxic chlorophyte Tetraselmis sp. (C; control condition), and combinations of C with 10 P. lima cells mL-1 (T10), 100 P. lima cells mL-1 (T100), or to a toxin concentration of ∼4 μg OA L-1 and ∼0.65 μg DTX-1 L-1 (T100d). Clams were exposed to these diets for 7 days (uptake phase), followed by a 7-day depuration period. No DSTs were detected in clams exposed to treatments C (control) nor to T100d (dissolved compounds) during either uptake or detoxification phase. Conversely, clams exposed to T10 or T100 accumulated, on average, up to 2.5 and 35 μg DST kg-1 in their whole bodies at the end of the uptake phase. These concentrations are ∼64 and ∼4.5 times lower than the regulatory level of 160 μg OA kg-1, respectively. Accumulated OA quotas were 12-22 times higher in the digestive gland (DG) than in remaining tissues over the uptake phase. Quick toxin transformation was indicated by the early detection of conjugated compounds - DTX-1 and OA esters - in the DG after 6 h of exposure, with OA-ester representing the main compound (30 - 100 %) in that tissue over the experiment. During the depuration period, detoxification rates represented 0.024 h-1, 0.04 h-1 and 0.052 h-1 for OA, DTX-1 and OA-ester, respectively. The activities of catalase, glutathione S-transferase, glutathione peroxidase and the levels of oxidative stress by lipoperoxidation varied similarly in the DG of A. flexuosa individuals subjected to T100, T100d and the control condition. However, contrasting antioxidant responses were measured in those exposed to T10. These findings indicate that no oxidative stress was primarily induced by DST-producing dinoflagellates in this clam species under laboratory conditions representative of toxic bloom situations. Even though, possible interactions should be considered under multistressor scenarios.

In this study, a hybrid ultrafiltration-forward osmosis system was compared with a dual stage ultrafiltration process for the harvesting of marine microalgae. To the best of the author's knowledge none of the previous studies compared the performance of a dual stage ultrafiltration process with a hybrid UF-FO process for the harvesting of marine microalgae. The application of the hybrid process is expected to reduce the energy consumption for harvesting the microalgae without affecting the concentration factor and final product quality. In forward osmosis, the impact of the feed and draw solutions flowrate and the membrane orientation was investigated. The feed solutions were unfiltered microalgae solution and ultrafiltered concentrated microalgae while the draw solution was brine collected from a thermal desalination plant. A maximum total algal harvesting concentration factor of 37.3 was obtained using the hybrid ultrafiltration-forward osmosis system and the dual stage ultrafiltration process. The flowrate used in the forward osmosis process was 2.5 LPM for the feed solution and 0.8 LPM for the draw solution and the active layer was facing the feed solution (i.e. FO mode). The energy consumption in the hybrid ultrafiltration-forward osmosis system was 24% less than the dual-stage ultrafiltration system. 2020 Elsevier B.V. This research is made possible by NPRP award (NPRP10-0117-170176) from Qatar National Research Fund (QNRF) . The statements made herein are solely the responsibility of the authors. In addition, the authors wish to thank QNRF for the financial support provided to one of the co-authors through a Qatar Research Leadership Program (GSRA6-1-0509-19021). The authors wish to thank the Central Laboratories Unit (CLU) at Qatar University for the ion chromatography analysis. Scopus

BPA is chemical pollutant of very high concern due to its toxicity to the environment and risks for human health. Environmental concern consists in BPA entrance into aquatic ecosystems due to acute and chronic toxicity to invertebrates and vertebrates. This study aimed to determine acute BPA toxicity to tropical estuarine-marine species of four trophic levels and integrate BPA toxicity values using species sensitivity distribution (SSD) analysis. Our hypothesis is that BPA toxicity increases towards higher trophic levels. Microalga (Tetraselmis sp.), zooplanktonic grazer (Artemia salina), deposit-feeder invertebrate (Heleobia australis), and omnivorous fish (Poecilia vivipara) were chosen as experimental models. Tetraselmis sp. showed the highest BPA tolerance, without a concentration-dependent response. Species sensitivity have increased from A. salina (LC50,96h = 107.2 mg L−1), followed by H. australis (LC50,96h = 11.53.5 mg L−1), to P. vivipara (LC50,96h = 3.5 mg L−1). Despite the toxicity hierarchy towards trophic levels, which partially supported our hypothesis, SSD did not evidence a clear pattern among estuarine-marine trophic groups. Our study disclosed the sensitivity of not yet investigated species to BPA and, in an integrative way, highlighted BPA toxic effects at different trophic levels. Although estimated acute hazardous concentration (HC5 = 1.18 mg L−1) for estuarine and marine species was higher than environmentally relevant concentrations, sublethal adverse effects induced by BPA exposure may lead to unbalances in population levels and consequently affect the ecological functioning of tropical coastal systems.

Corrosion control on petroleum pipe wells can only be done through the addition of corrosion inhibitors. In this study, the corrosion inhibitors studied were sourced from marine microorganisms, namely the type of microalgae Tetraselmis chuii sp. The aim to be achieved in this study was to determine the mechanism and efficiency of inhibition of the extraction of microalgae biomass in corrosion of carbon steel in an environment of petroleum conditions. To achieve this goal, a potentiodynamic polarization method (Tafel extrapolation) was used and the Electrochemistry Impedance Spectroscopy (EIS) method used the galvanostat-potentiostat device (Voltalab 40, PGZ 301). The results obtained from this study indicate that API 5L X65 carbon steel in the petroleum environment is very significantly corroded, caused by acidic media derived from acetic acid and dissolved CO2. The inhibition ability of the Tetraselmis chuii sp. Biomass extract. in line with the increasing extraction concentration reaching optimum at a concentration of 250 ppm with inhibition efficiency reaching 70%. The mechanism of inhibition takes place through the formation of a protective layer adsorbed on the surface of carbon steel. The protective membrane formed is uneven and tends to be porous.

There arose one of the most important ecological transitions in Earth’s history approximately 750 million years ago during the middle Neoproterozoic Era (1000 to 541 million years ago, Ma). Biomarker evidence suggests that around this time there was a rapid shift from a predominantly bacterial-dominated world to more complex ecosystems governed by eukaryotic primary productivity. The resulting ‘Rise of the algae’ led to dramatically altered food webs that were much more efficient in terms of nutrient and energy transfer. Yet, what triggered this ecological shift? In this study we examined the theory that it was the alleviation of phosphorus (P) deficiency that gave eukaryotic alga the prime opportunity to flourish. We performed laboratory experiments on the cyanobacteriumSynochystis salinaand the eukaryotic algaeTetraselmis sueciaand examined their ability to compete for phosphorus. Both these organisms co-occur in modern European coastal waters and are not known to have any allelopathic capabilities. The strains were cultured in mono and mixed cultures in chemostats across a range of dissolved organic phosphorus (DIP) conditions to reflect modern and ancient oceanic conditions of 0.2 μM P and 2 μM P, respectively. Our results show that the cyanobacteria outcompete the algae at the low input (0.2 μM P) treatment, yet the eukaryotic algae were not completely excluded and remained a constant background component in the mixed-culture experiments. Also, despite it’s relatively large cell size, the algaeT. sueciahad a high affinity for DIP. With DIP input concentrations resembling modern-day levels (2 μM), the eukaryotic algae could effectively compete against the cyanobacteria in terms of total biomass production. These results suggest that the availability of phosphorus could have influenced the global expansion of eukaryotic algae. However, P limitation does not seem to explain the complete absence of eukaryotic algae in the biomarker record before ca. 750 Ma.

The green alga Tetraselmis striata is regarded as a suitable candidate microalga for bio-diesel production. Recently, T. striata was cultured near Yeonghueung Island, Korea, in a &ldquo, marine culturing field&rdquo, however, its environmental impacts are not yet studied. We estimated the amount of dissolved organic carbon (DOC) released from T. striata cultivation in the marine culturing field, and we investigated the changes in bacterial composition. Then, we designed and installed a mesocosm for further understanding. From the mesocosm results, the DOC released from the cultivation of T. striata led to changes in bacterial communities, disturbance of the microbial food web structure, rapid depletion of nutrients, and a decrease in dissolved oxygen (DO) and pH. Our novel work demonstrates that large amounts of DOC secreted by large-scale microalgal cultures such as that of T. striata can potentially have a significant impact on the structure and function of the surrounding microbial ecosystem.

The forecasted growth of the aquaculture sector requires the use of novel and sustainable ingredients in aquaculture feeds. A study was undertaken to evaluate the effect of a 10% incorporation of defatted microalgal biomass (DMB) of Tetraselmis sp. CTP4, used at the expense of dehulled solvent-extracted soybean meal (SBM), on the growth performance, nutrient digestibility and physiological response to confinement stress in gilthead seabream juveniles. The trial comprised two dietary treatments: a control diet (CTRL) with relatively high levels of marine-derived proteins and 10% SBM; and a test diet (DMB10) with the incorporation of 10% DMB at the expense of SBM, while maintaining a fair constancy of all other ingredients. Triplicate groups of 30 fish, with a mean initial body weight of 6.0 +/- 0.2 g were fed the experimental diets for 61 days. At the end of the trial, fish tripled their initial body weight, but the overall growth performance criteria (final body weight, daily growth index, feed conversion ratio and protein efficiency ratio), whole-body composition and nutrient retention were not significantly affected by the dietary treatments (p > 0.05). The DMB10 diet showed a significantly higher apparent digestibility coefficients (ADC) of dry matter, energy and phosphorus (p < 0.05). When measured as an isolated feed ingredient, the DMB had an ADC of protein, fat, energy and phosphorus of 87.9, 85.3, 75.5 and 41.4%, respectively. After an acute confinement stress test, fish fed with DMB10 diet displayed a significantly lower plasma cortisol response (120 +/- 23 ng/mL) than those fed with the control diet (160 +/- 33 ng/mL) (p < 0.05). Overall results showed that DMB, issued from biorefinery processes, could potentially spare the use of soybean meal in aquaculture feeds, contributing towards a reduction of the current protein deficit in the European market. Sparos, Lda. Portuguese national budget Foundation for Science and Technology (FCT)Portuguese Foundation for Science and TechnologyEuropean Commission [UIDB/04326/2020] Compete 2020 [24517_VALORMAR] Lisboa 2020 [24517_VALORMAR] CRESC Algarve 2020 [24517_VALORMAR] Portugal 2020 [24517_VALORMAR] European Union through FEDER/ERDF FCTPortuguese Foundation for Science and TechnologyEuropean Commission [SFRH/BD/105541/2014] info:eu-repo/semantics/acceptedVersion

The presence of pharmaceutical and personal care product (PPCP) residues in the aquatic environment is an emerging issue due to their uncontrolled release through gray water, and accumulation in the environment that may affect living organisms, ecosystems and public health. The aim of this study is to assess the toxicity of benzophenone-3 (BP-3), bis-ethylhexyloxyphenol methoxyphenyl triazine (BEMT), butyl methoxydibenzoylmethane (BM), methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), 2-ethylhexyl salicylate (ES), diethylaminohydroxybenzoyl hexyl benzoate (DHHB), diethylhexyl butamido triazone (DBT), ethylhexyl triazone (ET), homosalate (HS) and octocrylene (OC) on marine organisms from two major trophic levels, including autotrophs (Tetraselmis sp.) and heterotrophs (Artemia salina). In general, results showed that both HS and OC were the most toxic UV filters for our tested species, followed by a significant effect of BM on Artemia salina due to BM&mdash, but only at high concentrations (1 mg/L). ES, BP3 and DHHB affected the metabolic activity of the microalgae at 100 &micro, g/L. BEMT, DBT, ET, MBBT had no effect on the tested organisms, even at high concentrations (2 mg/L). OC toxicity represents a risk for those species, since concentrations used in this study are 15&ndash, 90 times greater than those reported in occurrence studies for aquatic environments. For the first time in the literature, we report HS toxicity on a microalgae species at concentrations complementing those found in aquatic environments. These preliminary results could represent a risk in the future if concentrations of OC and HS continue to increase.

The fan mussel, Pinna nobilis, is an endemic Mediterranean species, whose populations have been seriously affected by infectious diseases. The effect of diet composition on growth and survival rates, and on nutritional metrics including ingestion and absorption rates, together with food preferences were investigated in 48 juveniles. Individuals were initially acclimated to conditions of captivity with a mixed diet of three species of microalgae cultured in situ and riverine sediment. Then, they were changed to different diets based on combinations of commercial phytoplankton gels and riverine sediments except for a control group that was maintained under the acclimation conditions. Diet A consisted of Tetraselmis chuii; diet B on a 2 species mix of T. chuii and Isochrysis aff. galbana (T-ISO), diet C on a 3 species mix T. chuii, T-ISO and Phaeodactylum tricornatum, diet D on riverine sediment without microalgae, and diet E on T. chuii and riverine sediment. Individuals under experimental diets were fed ad libitum once per day and the water with food excess replaced before the next ration. The control diet showed the highest survival and growth (50% vs. 2.5% survival and ca. 6 mm vs.

Cationic surfactants are surface-active compounds that can be found in many products, including household and cleaning agents. As a consequence, they tend to be discarded into water streams, ultimately ending up in the aquatic environment. In spite of this environmental issue, studies describing their effects towards marine species are lacking. The aim of this study was therefore to evaluate the short-term exposure effects of two commercial cationic surfactants and three novel gemini surfactants on four marine species, the green microalgae Nannochloropsis gaditana and Tetraselmis chuii, the diatom Phaeodactylum tricornutum, and the crustacean Artemia salina. Furthermore, biodegradation and size distribution of the cationic surfactants in artificial seawater were also studied by UV–vis spectrophotometry and dynamic light scattering, respectively. Ecotoxicity tests revealed that the commercial cationic surfactant N-cetyl-N,N,N-trimethylammonium bromide is toxic to all tested marine species while N-dodecyl-N,N,N-trimethylammonium chloride and 1,4-bis-[N-(1-dodecyl)-N,N-dimethylammoniummethyl]benzene dibromide showed the lowest toxicity among the tested cationic surfactants. Besides the novel insights regarding the effects caused by these five cationic surfactants, this work opens prospects for the replacement of commercially available surfactants by more environmentally friendly alternatives. published

Four different strains of marine algae viz. Tetraselmis tetrathele, Tetraselmis striata, Tetraselmis chuii, and Tetraselmis gracilis were isolated from the saltpans in Kovelong, Chennai, Tamil Nadu, India. The systematic position of Tetraselmis striata BBRR1 was confirmed through molecular identification. Under laboratory conditions, T. striata Butcher BBRR1 grown in f/2-medium recorded highest biomass concentration of 0.58 ± 0.021 g L−1, volumetric productivity of 0.025 ± 0.004 g L−1 d−1, 19 ± 2.3% proteins, 17 ± 1.5% carbohydrates, and 15 ± 2.4% lipids. Volumetric biomass productivity of 0.063 ± 0.08 g L−1 d−1, specific growth rate of 0.45 day−1 and lipid content of 19.42 ± 0.98% were recorded for the alga T. striata Butcher BBRR1 cultivated in 10-m2 open raceway ponds using Modified CFTRI ABRR1 medium. The fatty acid profile of T. striata Butcher BBRR1 showed the presence of 33.14% palmitic acid, 22.64% 11-octadecenoic acid, and 21.94% heptadecanoic acid. This study confirms the feasibility of cultivating the marine alga T. striata in open raceway ponds to produce biomass, which can be used for the production of biofuels.

U ovom radu ispitan je utjecaj morfoloških karakteristika stanica zelenih algi na međupovršinski proces adhezije, te na autonomno svojstvo pokretljivosti. Modelni organizmi korišteni u ovom istraživanju su Tetraselmis suecica i Dunaliella tertiolecta (Chlorophyceae), pokretne zelene alge mikrometarske veličine, različitih morfoloških karakteristika staničnog ovoja. Stanični ovoj D.tertiolecta čini mekana stanična membrana obavijena glikoproteinskim ovojem (glikokaliksom) dok stanični ovoj T.suecica čini stanična membrana sa složenom tekom načinjenom od ljusaka, inkrustiranom kalcijevim karbonatom. Stanice alga D.tertiolecta posjeduju dva biča jednake duljine koji izlaze iz jednog bazalnog tijela, dok stanice T.suecica imaju četiri biča, koja u par izlaze iz dva bazalna tijela. Primjenom elektrokemijske metode polarografije i kronoamperometrije na kapajućoj živinoj elektrodi karakterizirane su stanice D. tertiolecta na temelju karakterističnih signala prianjanja koji se javljaju na širokom području potencijala. Stanice T.suecica ne prianjaju na nabijenu elektrodu, što je posljedica kompaktnog staničnog ovoja. Primjenom optičke mikroskopije prikupljeni su video zapisi kretanja stanica alga direktno iz uzoraka stanične kulture. Video zapisi analizirani su programom otvorenog koda Icy (http://icy.bioimageanalysis.org/) pomoću kojeg je praćena brzina stanica, te duljina i oblik njihovih trajektorija. Na temelju analize 500 pojedinačnih stanica, brzina stanica T.suecica je do 4 puta veća od stanica D.tertiolecta što je posljedica složenog flagelarnog aparata. Dobiveni rezultati mogu doprinijeti boljem razumijevanju ponašanja stanica zelenih alga u vodenim sustavima

Light attenuation in photobioreactors is a major bottleneck in microalgal production. A possible strategy for artificial light-based microalgal production to deliver light deep inside the culture is through the periodical emission of high intensity light flashes (so-called flashing light). However, our results did not show improved photosynthetic rates compared to continuous light for dilute and concentrated Tetraselmis chui cultures exposed to flashing light with various repetition rates (frequencies 0.01 Hz–1 MHz), light-dark ratios (duty cycles: 0.001–0.7) or time-averaged light intensity (50–1000 μmol s− 1 m− 2). Likewise, flashing light applied to Chlorella stigmatophora and T. chui batch cultures could not enhance growth. However, we observed flashing light effects at different duty cycles and frequencies, depending on cell acclimation, culture concentration, and light intensity. In conclusion, artificial flashing light does not improve microalgal biomass productivities in photobioreactors, but low frequencies (f < 50 Hz) may be still used to improve light harvesting-associated biomolecules production.

The pattern of yellowish pigmentation of the skin was assessed in gilthead seabream (Sparus aurata) fed for 12 weeks iso-proteic (45%) and iso-lipidic (20%) diets deprived of fish meal and containing either a blend of vegetable protein-rich ingredients or where graded levels of the vegetable protein blend were replaced by insect (Hermetia illucens&mdash, 10%, 20% or 40%) pupae meal, poultry by-product meal (20%, 30% or 40%), red swamp crayfish meal (10%) and marine microalgae (Tisochrysis lutea and Tetraselmis suecica&mdash, 10%) dried biomass. Digital images of fish fed diets differing in protein sources were analyzed by means of an automatic and non-invasive image analysis tool, in order to determine the number of yellow pixels and their dispersion on the frontal and lateral sides of the fish. The relationship between the total carotenoid concentration in the diet and the number of yellow pixels was investigated. Test diets differently affected gilthead seabream skin pigmentation both in the forefront and the operculum, due to their carotenoid content. The highest yellow pixels&rsquo, number was observed with the diet containing microalgae. Fish fed poultry by-product meal were characterized by the lowest yellow pixels&rsquo, number, diets containing insect meal had an intermediate coloring capacity. The vegetable control, the microalgae mix diet and the crayfish diet had significantly higher values of yellow pixels at both inspected skin sites.

For mushroom production usually a mixture of horse and chicken manure and straw is used. For every kg of mushrooms, 5 kgs of waste is produced, a total of 800.000 tonnes per year in the Netherlands. Processing options are often either costly or complex. As the champost contains high salt concentrations, washing results in a solid (less salty) fraction with better re-use options and a nutrient-rich liquid fraction. On the latter fraction growth of five species of commercially relevant micro algae was tested in small-scale well tests. In addition, the press water was also treated with H2O2/UV to reduce the brown colour of the solution. In the majority of the triplicate well tests, growth of three of the five common saltwater algae species (Nannochloropsis gaditana, Porphyridium purpureum, and Tetraselmis chuii) on press water fractions of spent mushroom waste (champost) was found to be comparable to or better than their growth on control media. Dunaliella salina growth was relatively low. Arthrospira platensis only grew on press water when treated with H2O2. Overall, the results indicate that washing of champost results in a mineral rich solution suitable for growth of several (saltwater) algae.

The pyrolysis characteristic of the Tetraselmis chuii microalgae has been investigated through a thermogravimetric device. This experiment was carried out on 10 °C/min heating rate with 50 ml/min continuous nitrogen flow rate and 25-900°C temperature range. The results verified that four stages degradation processes were encountered during Tetraselmis chuii pyrolysis. During the pyrolysis process, the active region of volatile release occurs in two different stages. Degradation of carbohydrates and proteins take place in stage 2, whereas lipids are decomposed in stage 3. Analysis of kinetics parameters includes Ea (activation energy), A (pre-exponential factor), and n (reaction order) yielded the respective values of 70.68 kJ/mol, 1.72/minute, 1.22 and 223.25 kJ/mol, 11.43/minute, 2.44.

International audience; The culture of microalgae is important for the production and maintenance of bivalves. One of the major challenges is to maintain the reliability of microalgae forages over the long term. The aim of this work is to use Ultrafiltered (UF) seawater to cultivate them. Thus, cultures in a volume of 300 L of 2 species of microalgae Tetraselmis and T-isochrysis, were monitored in UF water (membrane pore size: 20 nm) and in sea water usually used on the Ifremer mollusk experimental platform of Bouin (France) (Prefiltration, 3 filtrations and 2 UV). The major result is the securing of microlagae cultures with the absence of parasites in all cultures supplied with ultrafiltered water, unlike analyses of the various control cultures. In the case of T-isochrysis, 3 cultures out of 4 resulted in higher microalgae concentrations, up to 30%, in ultrafiltered water thus bringing a benefit on the algal density. These conclusions and the ease of recovering water (linked to the reduction in treatment stages) allowed a transfer of technology. In fact the 300 L cultures hitherto carried out on the experimental platform are now produced in ultrafiltered water since early 2019.

Pulsed electric fields (PEF) is a promising technology that allows the selective extraction of high-added value compounds by electroporation. Thus, PEF provides numerous opportunities for the energy efficient isolation of valuable microalgal bioactive substances (i.e., pigments and polyphenols). The efficiency of PEF-assisted extraction combined with aqueous or dimethyl sulfoxide (DMSO) solvents in recovering pigments and polyphenols from microalgae Tetraselmis chuii (T. chuii) and Phaeodactylum tricornutum (P. tricornutum) was evaluated. Two PEF treatments were applied: (1 kV/cm/400 pulses, 3 kV/cm/45 pulses), with a specific energy input of 100 kJ/kg. The total antioxidant capacity (TAC) was positively influenced by the use of DMSO. The highest TAC in the T. chuii culture was achieved at a lower extraction time and electric field than for P. tricornutum. The use of DMSO only improved the polyphenols&prime, extraction for P. tricornutum, whereas the PEF and extraction time were more important for T. chuii. Carotenoids and chlorophyll a were more efficiently extracted using DMSO, while chlorophyll b levels were higher following aqueous extraction for both microalgae. In P. tricornutum, the TAC and pigment extraction efficiency were in general higher at lower extraction times. It can be concluded that PEF may be a promising alternative for the enhancement of the selective extraction of antioxidant bioactive compounds from microalgae.

Recently isolated microalgae Tetraselmis sp. IMP3, Tetraselmis sp. CTP4, and Skeletonema sp. were studied. The three novel strains contained relatively high levels of polyunsaturated fatty acids (PUFA) and n3 PUFA. However, highly unsaturated n3 FA contents were relatively low (5.7-13.0% of the total FA). In general, eicosapentaenoic acid (EPA, 20:5 n3) contents were low (< 6.4% of the total FA). However, in Skeletonema biomass, EPA levels were higher than 10% of the total FA. alpha-Linolenic acid (ALA, 18:3 n3) and 16:3 n4 were the main PUFA in Tetraselmis strains and Skeletonema, respectively. High contents of myristic (14:0) and palmitoleic (16:1 n7) acids were found in Skeletonema (exceeding 20% of the total FA in both cases), whereas the Tetraselmis strains were rich in palmitic (16:0), 15-27% of the total FA, and oleic (18:1 n9) acids, 12-19% of the total FA. Linoleic acid (18:2 n6) content was low in Skeletonema (< 1% of the total FA). This microalga had the highest total polyphenol content, reaching 300-400 mg/100 g dw. Gentisic acid was the main phenolic compound in the aqueous and ethanolic extracts of this microalga. The highest antioxidant activity was displayed by Skeletonema. The ferric ion reducing antioxidant power (FRAP) and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods showed higher antioxidant power for Skeletonema sp. extracts, reaching an ABTS reduction of more than 80%. Concerning anti-inflammatory activity, ethanolic extracts of Skeletonema sp. exhibited the highest inhibitory capacity of cyclooxygenase-2 (COX-2), 82 +/- 2%, which compares to 36 +/- 9% in Tetraselmis sp. CTP4 and 45 +/- 5% in Tetraselmis sp. IMP3. Aqueous extracts had always a lower anti-inflammatory capacity, 6-30%. Therefore, these microalgae have potential for multiple applications, ranging from bioactive feedstocks to aquaculture and nutraceutical uses. SFRH/BPD/102689/2014, (SFRH/BD/129795/2017, SFRH/BD/105541/2014, project 0055 ALGARED+ 5E-INTERREG V-A info:eu-repo/semantics/publishedVersion

The feasibility of substituting 50% nutrients by aqueous phase liquid (APL), derived from hydrothermal liquefaction of Tetraselmis sp. biomass, in a semi-continuous cultivation of Tetraselmis sp. was studied. Growth experiments were conducted in indoor photobioreactor and outdoor raceway tank for three consecutive cycles. At the end of exponential growth pahse, 75% of the culture was harvested, and the supernatant was returned to the cultivation system. For control cultures, fresh nutrients were added; however, for the experimental cultures, an appropriate volume of APL was added to replace half of the nutrients. Either indoor or outdoor, the growth rate and biomass yield in APL-added cultures were either equal or slightly better compared to control culture; although APL had little to no effect on the metabolite content of Tetraselmis sp., metabolites profile of Tetraselmis sp. varied between APL-added and control cultures. Nevertheless, 50% nutrients requirements for microalgae cultivation could be replaced by APL. 2019 Elsevier Ltd The authors would like to acknowledge the support of Qatar National Research Fund (QNRF, a member of Qatar Foundation) for providing the funding (under grant NPRP8-646-2-272 ) for this study. Scopus

The interaction amongst microalgae might hold the key to the increase of biomass and lipid production from microalgae culture. A mixed culture of microalgae shows to have a higher biomass and lipid content than a single culture. A local mixed culture from Glagah Beach, Yogyakarta, later called Glagah strain is one of the natural mixed culture. Several microalgae species have a high biomass either lipid content and the biomass and lipid possibly get higher in mixed culture. There were 2 treated microalgae mixed culture in this research, there were natural mixed culture and artificial mixed culture, while Glagah strain as the control. Natural mixed culture was composed of Glagah strain, and 3 different microalgae species, they were Tetraselmis sp., Spirulina sp., Chlorella zofingiensis Donz, and Bottryococcus sp. Artificial mixed culture was composed only those 4 microalgae species. The aims of this research were know the microalgae density, biomass, and lipid content on the Glagah strain, natural mixed culture, and artificial mixed culture. It used Bold’s Basal Medium (BBM) 2N to cultivate the 3 kind of cultures for 10 days. Density, biomass, and lipid content of the microalgae cultures were measured. The result shows that the natural mixed culture had a higher total cells than the artificial mixed culture which are 7,350,00 cells in the seventh day. The natural mixed culture also showed to has a higher lipid content than the artificial mixed culture by 0.004 mg. The natural mixed culture has a higher lipid content than the artificial mixed culture and Glagah strain at the fourth day, which were 0.0015 mg. It can be concluded that the natural mixed culture had rapid growth and higher biomass productivity compared to the artificial mixed culture but still lesser than Glagah strain. The artificial mixed culture had a higher lipid content compared to Glagah strain and natural mixed cultures.

Heavy metals are widely dispersed water pollutants due to industrial, agricultural and urban development and they have a significant impact on organisms in water ecosystems. Microalgae cells are mostly very sensitive to changes in the environmental factors such as temperature, salinity, light intensity and also the presence of toxic pollutants in their environment, which are responsible for their growth and physiology, and also autonomous cell features such as photosynthesis and motility. The aim of this work was to examine the algal cell motility in stress conditions. As model organisms we used three species of microalgae Dunaliella tertiolecta (Chlorophyceae), Rhodomonas maculata (Cryptophyceae) and Tetraselmis suecica (Chlorophyceae), that differ in the structure of the flagellar apparatus. Microalgae in growth medium were exposed to cadmium concentration of 1000 µg/L. The mathematical model enabled to determine free cadmium concentration that act as toxicants to algal cell [1]. We employed open- access software Icy (http://icy.bioimageanalysis.org/) to perform motility analysis of cells in the growth medium. The results will be presented in terms of cell velocity and search path of three microalgal species. This study could contribute to better understand cell behavior change when exposed to stress without any sample pretreatment.

This study aimed to examine the influence of the morphological characteristics of green algal cells on the adhesion process and their mobility. The used model organisms were Tetraselmis suecica and (Chlorophyceae), motile microalgae of micrometer size, with different morphological characteristics of the cell envelope. The D. tertiolecta cell consists cell membrane [1, 2] enveloped by a glycoprotein cover (glycocalyx), while T. suecica cell consists of a cell membrane with complex theca made of scales, encrusted with calcium carbonate. D. tertiolecta cells have two flagella of equal length emerging from one basal body, whereas T. suecica cells have four flagella that pair out of two basal bodies. Using the electrochemical method of polarography and chronoamperometry on a dropping mercury electrode, D. tertiolecta cells were characterized based on characteristic adhesion signals occurring over a wide potential range. T. suecica cells do not adhere to the charged electrode, which is a consequence of the compact cell envelope. Using computer-assisted video microscopy and an Open Source Image Processing Software Icy (http://icy.bioimageanalysis.org/) cell swimming speed, the displacement length, and shape of their trajectories were quantified on 500 individual cells. Results showed that the speed of T. suecica cells is up to 4 times higher than that of D. tertiolecta, which is a consequence of a complex flagellar system. Based on algal cell adhesion and motility characterization, the obtained results could contribute to a better understanding of the spatial distribution of green algal cells in the aquatic environment under stress

Lipid-extracted microalgae (LEM, Tetraselmis KCTC 12236BP), a solid waste by-product obtained from algal biodiesel production, is typically considered a rich source of antioxidant compounds, including phenolic compounds. The purpose of this study was to apply a statistically-based methodology to enhance the extraction of total phenolic compounds (TPCs) and antioxidant activity (AA) from LEM and to verify the production of epigallocatechin gallate (EGCG), a bioactive material, under optimum conditions. The optimal extractions of TPC and AA were explored by varying the key variables, including the extraction temperature, ethanol concentration, extraction time, and ultrasonic power, through statistical optimization. The optimal extraction conditions were identified through 27 runs following the central composite design. The regression analyses of TPC and AA showed good fit of the experimental data to the second-order polynomial models, with coefficient of determination (R2) values of 0.8769 and 0.8432, respectively. In the variation experiment, the maximum TPC and AA values of 9.8 mg GAE/g and 91.8% were obtained respectively with an extraction temperature of 74.4 &deg, C, ethanol concentration of 55.4%, extraction time of 59.6 min, and ultrasonic power of 700 W. HPLC coupled with diode array detection was used to identify and quantify the phenolic compounds in the extracts, and EGCG (0.12 mg/g DM) was identified as a major peak in the analysis, demonstrating that high value-added material with a bioactive property can be produced from LEM. The results indicated that statistical optimization is applicable for optimizing the extraction of TPC and AA from LEM and provided a scientific basis for applying ultrasound-assisted extraction on an industrial scale by optimizing the conditions. LEM has a high TPC value, particularly with regard to EGCG, and excellent AA, considering it is highly used as a functional material for food, cosmetics, and medicine.

Several species of the genus Tetraselmis (Chlorodendrophyceae, Chlorophyta) were recently discovered to possess unsuspected biomineralization capacities: they produce multiple intracellular inclusions of amorphous calcium carbonate (ACC), called micropearls. Early light-microscopists had spotted rows of refractive granules in some species, although without identifying their mineral nature. Scanning electron microscope (SEM) observations showed that the distribution of the micropearls in the cell forms a pattern, which appears to be characteristic for a given species. The present study shows that this pattern correlates with the shape of the chloroplast, which differs between Tetraselmis species, because micropearls align themselves along the incisions between chloroplast lobes. This was observed both by SEM and in live cells by light microscopy (LM) using Nomarski differential interference contrast. Additionally, molecular phylogenetic analyses, of rbcL and ITS2 gene sequences from diverse strains of Chlorodendrophyceae, corroborated the morphological observations by identifying two groups among nominal Tetraselmis spp. that differ in chloroplast morphology, micropearl arrangement, and ITS2 RNA secondary structure.