Sulfitobacter porphyrae ZFX1, isolated from surface seawater of the East China Sea during a Prorocentrum donghaiense bloom recession, exhibits high algicidal activity against P. donghaiense. To evaluate the algicidal effect of ZFX1, the algicidal mode and stability were investigated. The results showed that ZFX1 indirectly attacked algae by secreting algicidal compounds, and the algicidal activity of the ZFX1 supernatant was insensitive to different temperatures, light intensities and pH values (pH 3–12). To explore the algicidal mechanism of the ZFX1 supernatant, its effects on the morphological and ultrastructural alterations, photosynthetic capacity, reactive oxygen species (ROS) and antioxidative system of P. donghaiense were investigated. Scanning and transmission electron microscopy revealed that the ZFX1 supernatant destroyed the algal cell membrane structure and caused intracellular leakage. The decrease in the chlorophyll a content and the marked declines in both the photosynthetic efficiency (Fv/Fm) and the electron transport rate (rETR) indicated that the ZFX1 supernatant could damage the photosynthetic system of P. donghaiense. The excessive production of ROS in algal cells demonstrated the oxidative damage triggered by the ZFX1 supernatant. Although the antioxidant defense system of P. donghaiense was activated to scavenge excessive ROS, lipid oxidation occurred. The fatty acid composition profile indicated that the ZFX1 supernatant markedly increased the contents of two saturated fatty acids and a monounsaturated fatty acid and decreased the proportion of two polyunsaturated fatty acids, which resulted in lipids with a lower degree of unsaturation (DU). The decline in the DU decreased the lipid fluidity and rigidified the membrane system, and these effects destroyed the function of the membrane system and ultimately resulted in algal cell death. Therefore, ZFX1 probably plays a key role in mitigating P. donghaiense bloom by inducing lipid oxidation, decreasing the DU of lipids and ultimately destroying the membrane systems of algal cells.

In our study, Bufo gargarizans (B. gargarizans) larvae were exposed to control, 0.5, 5, 10 and 50 mg/L of NaF from Gs 26 to 42. At Gs 42, we evaluated the changes of liver histology and the mRNA levels of target genes in liver. In addition, we also examined the composition and content of fatty acids. Histological analysis revealed that fluoride caused liver injury, such as the increase of number of melanomacrophage centres, atrophy of nucleus, dilation of bile canaliculus, and decrease of quantity, degradation and deposition of lipid droplets. The results of RT-qPCR indicated that exposure to 5, 10 and 50 mg/L of NaF significantly decreased the transcript levels of genes related to fatty acid synthesis (FASN, FAE, MECR, KAR and TECR) in liver. Besides, mRNA expression of genes involved in fatty acid β-oxidation (ECHS1, HADHA, SCP2, CPT2, ACAA1 and ACAA2) and oxidative stress (SOD, GPx, MICU1 and HSP90) was significantly downregulated in 0.5, 5, 10 and 50 mg/L of NaF treatment groups. Also, in the relative expression of genes associated with synthesis and secretion of bile acid, BSEP significantly increased at 0.5, 5 and 50 mg/L of NaF while HSD3B7 significantly reduced in 0.5, 5, 10 and 50 mg/L of NaF. Finally, the fatty acid extraction and GC-MS analysis showed that the content of saturated fatty acids (SFAs) was decreased and the content of polyunsaturated fatty acids (PUFAs) was increased in all fluoride treatment groups. Taken together, the present results indicated that fluoride-induced the histological alterations of liver might be linked to the disorder of lipid metabolism, oxidative damage.

In the general population, chronic exposure to low-dose persistent organic pollutants (POPs), particularly organochlorine pesticides (OCPs), has been recently linked to many chronic diseases. Widespread contamination of the food chain and human adipose tissue has made avoiding exposure to these chemicals impossible; thus, alternative strategies for decreasing the chemical burden must be investigated. Recently, macronutrient intake was found to significantly modify the toxicokinetics of POPs in animal experimental studies. Thus, we evaluated whether macronutrient intake was related to serum concentrations of OCPs in healthy adults without cardio-metabolic diseases. Subjects included 1,764 adults, aged 20 years or above, who participated in the National Health and Nutrition Examination Survey 1999–2004. Macronutrient intake was assessed based on a 24-h dietary recall interview. Six individual OCPs commonly detected among the general population were evaluated as markers of OCPs and other coexisting lipophilic chemicals stored in adipose tissue and released into circulation. High fat intake was associated with lower concentrations of OCPs, while high carbohydrate intake showed the opposite result. When three types of fats were individually evaluated, both saturated fatty acids and monounsaturated fatty acids, but not polyunsaturated fatty acids, were inversely associated with serum concentrations of OCPs. Adjustment for possible confounders did not change the results. When stratified by age, gender, body mass index, and physical activity, these associations were similar in most subgroups. Thus, similar to the findings observed in animal experimental studies, a moderate-fat diet with low carbohydrate intake was related to low serum concentrations of OCPs in humans. Although these findings need to be replicated, changing dietary macronutrient intake can be investigated as a practical strategy for dealing with unavoidable lipophilic chemical mixtures such as OCPs in modern society.

Two stages of selection from a pool of 56 fatty acids analyzed in Helix pomatia yielded a set of 12 biomarker acids undergoing significant changes in contact with three microdoses of toxic substances, i.e. three molluscicides containing metaldehyde, methiocarb, and potassium chloride (PC). The proposed palette of acids, including saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), determined separately in the foot tissues and hepatopancreas of Gastropoda, can be used in ecotoxicological research as a reliable test of the effect of trace doses of stressors. The final set of the biomarker FA comprised C16:0; C18:0; C23:0; C18:1 n-9; C20:1 n-9; C18:2 n-6; C18:3 n-3; C20:2; C20:4 n-6; C20:5 n-3; C22:4 n-6; and C22:5 n-3. A clear physiological response manifested as changes in the content of fatty acids (FA) was observed in the snails even in the case of the lowest doses of the pollutants. All experimental factors analyzed, i.e., the dose (5, 10, or 15 μl 0.01% w/v concentration) and the type of preparation (metaldehyde, methiocarb or PC), had a significant (p ≤ 0.01) impact on the FA composition of the foot and hepatopancreas. Limitation of the analysis to a narrow pool of reactive FA meets the requirements of parameters of biomarkers of exposure and facilitates and accelerates visualization of the bioindicator organism's response to the presence of the stressor in the environment.

Fatty acids (FAs) composition, 24 persistent organic pollutants (POPs), and 16 trace elements were examined in small pelagic fish (sardine, anchovy, round sardinella, chub and horse mackerels) caught by a fishing fleet for more than three years in the eastern Mediterranean Sea. Five Unmix source profiles associated with both sources, such as overlapping diet, including low-niche marine organisms and inputs from the surrounding environmental compartments were resolved. Inorganic compounds were notably more abundant in fish tissue than organochlorine xenobiotics. Comparison with the values of toxicological parameters revealed that the examined fish species are safe for human consumption, while the content of FAs emphasized the studied species as a valuable source of nutrients. A significant linear correlation was not observed between the 18 FAs and lipophilic organochlorines. Based on the obtained database, future assessments of the quality of edible fish species and the aquatic environment of the eastern Mediterranean Sea, which is known as an important fishing ground, could be significantly improved.

Global warming is emerging as one of the most critical threats to terrestrial and marine species worldwide. This study assessed the effects of simulated warming events in culture on two seagrass species, Posidonia oceanica and Cymodocea nodosa, which play a key role in coastal ecosystems of the Mediterranean Sea. Changes in fatty acids as key metabolic indicators were assessed in specimens from two geographical populations of each species adapted to different in situ temperature regimes. Total fatty acid (TFA) content and composition were compared in C. nodosa and P. oceanica from natural populations and following exposure to heat stress in culture. After heat exposure, individuals of C. nodosa and P. oceanica adapted to colder temperatures in situ accumulated significantly more TFA than controls. For both species, the proportion of polyunsaturated fatty acids (PUFA) decreased, and the percentage of saturated fatty acids (SFA) increased significantly after the heat treatment. These results highlight that populations of both species living at warmest temperatures in situ were more thermo-tolerant and exhibited a greater capacity to cope with heat stress by readjusting their lipid composition faster. Finally, exposure of seagrasses to warmer conditions may induce a decrease in PUFA/SFA ratio which could negatively affect their nutritional value and generate important consequences in the healthy state of next trophic levels.

Foodwaste leachate (FWL) is often generated during foodwaste treatment processes. Owing to its high nutrient content, FWL has high potential for phycoremediation, a microalgal technology application for water treatment while acting as CO₂ fixation tank. Additionally, the end product of microalgal from phycoremediation can be potentially used for biodiesel production. Therefore, the phycoremediation has drawn a lot of attention in recent decades. This study evaluates the performance of microalgal foodwaste leachate treatment and the potential of utilizing FWL as medium for microalgal biodiesel production. Two microalgal species, Dunaliella tertiolecta and Cyanobacterium aponinum, were selected. For each species, two experimental levels of diluted FWL were used: 5 and 10% FWL. The partial inhibition growth model indicates that some inhibit factors such as ammonia; total suspended solids and oil and grease (O&G) content suppress the microalgal growth. Most of the nutrient such as nitrogen and phosphorus (> 80%) can be removed in the last day of phycoremediation by D. tertiolecta. C. aponinum also show considerable removal rate on total nitrogen ammonia and nitrate (> 60%). Biomass (0.4–0.5 g/L/day) of D. tertiolecta and C. aponinum can be produced though cultivated in diluted FWL. The bio-CO₂ fixation rates of the two species were 610.7 and 578.3 mg/L/day of D. tertiolecta and C. aponinum. The strains contain high content of saturated fatty acid such as C₁₆ and C₁₈ making them having potential for producing good quality biodiesel.

CO₂, SO₂, and NO are the main components of flue gas and can cause serious environmental issues. Utilization of these compounds in oleaginous microalgae cultivation not only could reduce air pollution but could also produce feedstock for biodiesel production. However, the continuous input of SO₂ and NO inhibits microalgal growth. In this study, the toxicity of simulated flue gas (15% CO₂, 0.03% SO₂, and 0.03% NO, balanced with N₂) was reduced through automatic pH feedback control. Integrated lipid production and CO₂ fixation with the removal of SO₂ and NO was achieved. Using this technique, a lipid content of 38.0% DW was achieved in Chlorella pyrenoidosa XQ-20044. The lipid composition and fatty acid profile indicated that lipid production by C. pyrenoidosa XQ-20044 cultured with flue gas is suitable as a biodiesel feedstock; 81.2% of the total lipids were neutral lipids and 99.5% of the total fatty acids were C16 and C18. The ratio of saturated fatty acids to monounsaturated fatty acids in the microalgal lipid content was 74.5%. In addition, CO₂, SO₂, and NO from the simulated flue gas were fixed and converted to biomass and lipids with a removal efficiency of 95.9%, 100%, and 84.2%, respectively. Furthermore, the utilization efficiencies of CO₂, SO₂, and NO were equal to or very close to their removal efficiencies. These results provide a novel strategy for combining biodiesel production with biofixation of flue gas.

Suspended sediments (SSs) were examined regarding the content of fatty acids (FAs) to associate them with sources of soil entry into the river. The source of organic matter was traced through fatty acid distribution, as well as erosion. Also, TOC, TN, and TOC/NT were used to support the results of FAs. For this, a tropical river was chosen to understand the main source of input considering the level of land occupation along the river. The Barigui river, in southern Brazil, was segmented in four distinct areas regarding the soil occupation (P1, P2, P3, and P4). Nine sampling campaigns were conducted from Nov/2014 to Nov/2015 using a time-integrated sampler. Site P1 has the lowest level of urbanization and showed the lowest concentration of FAs (16.35 μg⁻¹). In contrast, site P4, the most urbanized, showed the highest content of fatty acids, including those associated with erosion, 378.53 μg g⁻¹, specifically those with long chains. The mean concentrations of the saturated fatty acids (FAs) was 283.40 μg g⁻¹, monounsaturated fatty acids (MUFAs) was 79.46 μg g⁻¹, and polyunsaturated fatty acids (PUFAs) was 15.66 μg g⁻¹. Twenty-seven fatty acids were examined, nevertheless C15:0, C16:0, C18:0, and C18:1ω9 prevailed in all samples. Generally, those acids indicate sewage inputs. Statics analyses were used to find the relation between the source of organic matter (autochthonous, allochthones, and anthropogenic) and FAs. Finally, the input of organic matter is associated with land occupation, which can be distinguished by FA distribution.

Microalgae-based treatment systems have been successfully used for the polishing of domestic wastewater. Research is underway in studying the suitability of using these systems as main treatment units. This study focuses on comparing the performances of a mixed microalgal culture and an aerobic bacterial culture, based on the kinetic evaluation, in removing organic carbon from a kitchen wastewater. The two systems were operated at six different solid retention times (SRTs)—2, 4, 6, 8, 10, and 12 days in continuous mode. The influent and effluent samples were analyzed for chemical oxygen demand (COD), total organic carbon (TOC), total nitrogen (TN), phosphates, and surfactants. Steady-state kinetics (k, Kₛ, Y, and kd) for organic carbon removal were obtained by fitting experimental data in linearized Michaelis-Menten and Monod equations. The mixed microalgal system showed similar or better performance in COD and TN removal (88 and 85%, respectively) when compared with the COD and TN removal by the aerobic bacterial system (89 and 48%). A maximum lipid yield of 40% (w/w of dry biomass) was observed in the microalgal system. Saturated fatty acids accounted for 50% of the total observed FAME species. The study indicates that the mixed microalgal culture is capable of treating kitchen wastewater and has the potential to replace aerobic bacteria in biological treatment systems in certain cases.