جستجوی مقالات مرتبط با کلیدواژه « Chlorophyll » در نشریات گروه « شیلات »

Agricultural effluents contain nutrients such as phosphates, nitrates and ammonia, which cause surface and underground water pollution. By absorbing these nutrients, freshwater algae such as Spirulina can play an important role in reducing these types of pollutants. On the other hand, this type of wastewater, having nutrients, can be used as an alternative and cheap substrate for algae cultivation. Five concentrations of diluted sugarcane effluent (0, 25, 50, 75, and 100%) were prepared with Zarrouk’s medium and the growth rate, photosynthetic pigments, and the amount of some mineral substances, protein, and fat composition were evaluated. In high concentrations of wastewater (75 and 100% wastewater treatment), a very good growth of Spirulina was observed.The amount of chlorophyll a in the treatment of 100% of wastewater showed a significant increase compared to the control treatment (p < 0.05). The maximum amount of total carotenoids in the treatment of 50% of the Zarrouk’s medium was obtained at the rate of 1559 ± 226 mg/liter, which was more than 2 times the amount of total carotenoids in the control treatment. The maximum amount of total carotenoid in the treatment of 50% of Zarrouk’s medium was 1559 ± 226 mg/liter, which was more than 2 times the amount of total carotenoid in the control treatment.In addition, the produced algae can be used as livestock and aquatic food.

The most important limitation of the mass production of Spirulina microalgae in the world is the high cost of its culture medium. The present study was carried out with the aim of evaluating the cultivation mediums based on chemicals and commercial fertilizers and comparing the growth  characteristics, pigments, and the amount of protein in the produced spirulina in comparison with the Zarrouk’s medium. In order to meet the nutritional needs of Spirulina species, low-cost fertilizers were used in the form of 18 treatments and three replications. In all treatments, commercial sodium bicarbonate at 16.8 g/L, sea salt at 0.5 g/L, and the commercial liquid fertilizer (K:P, 20:20) were used to meet the phosphorus and potassium needs of the microalgae. To supply nitrogen in the treatments, three sources of sodium nitrate, urea, and a 50:50 combination of both were used. In all three groups, 6 substances were used in the form of 6 treatments (control, potassium, iron, a combination of potassium and iron, magnesium, and micronutrients). According to the results, the growth of Spirulina was higher in the control group (Zarrouk’s medium) than other treatments until the 20th day, but after that, the sodium nitrate -magnesium (N-Mg) treatment showed a higher growth rate than the control group. Also, the highest specific growth rate, cell density of algae, and the lowest doubling time were measured in the treatment containing sodium nitrate source. The highest algal cell density and specific growth rate were significantly (p<0.05) observed in sodium nitrate-magnesium (N-Mg) and sodium nitrate-micronutrients (N-Mic) treatments, which were significantly different from the control group (Zarrouk’s medium). The maximum chlorophyll a, chlorophyll b, and total pigment were obtained significantly in sodium nitrate-micronutrients (N-Mic) treatment (p<0.05). The highest amount of protein was obtained in the combined sodium nitrate-urea group with iron and potassium sources. To sum up, the highest growth rate and the highest cell density were obtained in the culture medium containing sodium nitrate, which is comparable to Zarrouk’s culture medium that can be used on a commercial scale.

In this study, the effect of lack and phosphorus deficiency (dipotassium phosphate; K2HPO4) on the growth rate, biomass, biochemical content, and fatty acid profile of Desmodemus sp. was investigated for 14 days. Accordingly, Desmodesmus microalgae were grown in culture media containing no phosphorus (P0), 10 (P10), 20 (P20), 30 (P30), and 40 mg/liter (P40). The P40 treatment was considered as a control group that had the amount of phosphorus required in the standard culture medium BG11. Based on the results, the highest cell density, specific growth rate, and biomass production were simultaneously recorded in the P20, P30, and P40 treatments on the 14th day of culture, which showed a significant difference from the other two groups (P<0.05). In addition, the highest chlorophyll a was also recorded in these three groups, which showed a significant increase compared to the group without phosphorus (P<0.05). The lowest chlorophyll b was recorded in P0 (1.62 mg/L) compared to other experimental groups (P<0.05). The analysis of body composition showed the highest amount of lipid productivity (14.93 mg/liter per day) in P20 treatment, which has a significant difference with other experimental groups, except for P10 (13.17 mg/liter per day) (P<0.05). The highest protein productivity rate was measured in P30 and P40 groups (P<0.05) and the highest carbohydrate productivity rate (10.55 mg/L per day) was measured in P40 without significant difference with P30 (8.87 mg/l per day). The highest amount of saturated fatty acids was observed in P0 (47.66% of total fat) and the highest long-chain unsaturated fatty acids in P40 treatment (30.58% of total fat) without significant difference with P30 (29.33% of total fat). Based on the results, the concentration of 20 mg/liter of phosphorus is a suitable concentration for the cultivation of Desmodesmus sp. microalgae for the production of biofuel, while the concentration of 40 mg/liter of phosphorus is a suitable concentration for the cultivation of the microalgae for using in the food and aquafeed industries.

In today's world, the extensive human use of pesticides to control agricultural pests and their entry into water resources is a threat to aquatic ecosystems. In this study, Reduction of Chloriprifos organophosphate pesticide from aqueous environment was investigated by bioremediation method by Anodonta cygnea oyster as a bio filter. During a period of twelve days, three treatments with three replications were exposed to three different concentrations of pesticide, 30, 20, 15 mg / l. And indices of toxin concentration, light absorption, water pH and oyster filtration rate were measured to determine the reduction of toxin concentration. At the end of the experiment, the amount of pesticide concentration for treatments with concentrations of 30, 20 and 15 mg/L pesticides were 19 ± 0.1, 4.6 ± 0.153, 3 ± 0.133, with a reduction efficiency of 36.67%, 76.83%, 100% respectively. Percent, Light absorption rate 0.44 ± 0.001, 0.011 ± 0.002, 0.000 ± 0.000 with a reduction efficiency of 38.04%, 77.75%, 100% and a pH of 7.53, 99/7, 6/8 were estimated. Filtration rate for treatments with concentrations of 30 and 20 mg/L pesticides decreased and for treatment with 15 mg/L pesticide concentration had an increasing trend. There was a significant difference between changes in toxin concentration, light absorption miran and filtration rate at the beginning and end of the experiment (P˂0.05). Anodonta cygnea species as a suitable bioremediator for the removal of chlorpyrifos pesticides in agricultural wastewater treatment systems or contaminated natural water environments is recommended, however, further studies are needed in this area.