Littérature scientifique sur le sujet « Astaxathin »

Astaxanthin is classified as a xanthophyll-carotenoid, which is red-orange colour and powerful antioxidant activity. In this study, astaxanthin was collected from Rhodosporidum sp. by pilot culture (10 liters). Molasses medium was investigated with urea ((NH4)2CO), magnesium sulfate heptahydrate (MgSO4.7H2O) and potassium dihydrogen phosphate (KH2PO4) at different concentrations. Astaxanthin was extracted by using chlorhydric acid (HCl) method.The highest dried yeast biomass was 8.3682 g/l culture supernatant and astaxathin was 1.932 g/l culture supernatant by molasses medium containing 20 g/l sugar, 0.5 g/l ((NH4)2CO, 3 g/l MgSO4.7H2O and 10 % (v/v) inoculum. HCl extraction method was mixed 10 mg biomass: 1 ml HCl 0.6 N and incubated at 70 oC, 150 minutes.

Taking β-cyclotextrin and gelatin as wall materials, study of inclusion was processed on astaxanthin. It was shown in the study that β-cyclotextrin and gelatin at the ratio of 4 to 1 was found to be the best wall material for inclusion complex. The optimal conditions of inclusion were established by the RSM experiment: when the amount of wall material was 0.4 g/g yeast, temperature 40°C, time 1.2 h, the inclusion rate could reach 81.03%. The characterization of the inclusion complex was confirmed by different temperatures and light, the result shows that the inclusion complex could improve the stability of astaxanthin. The inclusion complex was stored in dark at 4°C for 60 days, the residual rate of astaxathin could reach 95% and more stable than that before inclusion by 35%.

Phương pháp phân tích HPLC sử dụng detector PDA đã được khảo sát và lựa chọn để xác định một số hoạt chất nhóm xanthophyll (astaxathin, lutein và zeaxanthin) trong thực phẩm bảo vệ sức khỏe (TPBVSK). Cột tách C30 và pha động đẳng dòng gồm ethyl acetat: acetonitrile (12:88, v/v) chứa 0,1% n-decanol cho thấy khả năng tách tốt nhất đồng thời ba chất. Các xan- thophyll thường tồn tại ở dạng este được xà phòng hóa bằng dung dịch KOH 45% (với lutein và zeaxanthin) và 1% (với astaxanthin) ở 60oC trong 15 phút, sau đó chiết lại với n-hexan trước khi phân tích trên hệ thống HPLC. Kết quả thẩm định cho thấy phương pháp có độ đặc hiệu và độ chọn lọc cao, đường chuẩn tuyến tính trong khoảng 0,5 – 10 µg/ml, độ lặp lại và độ thu hồi đáp ứng được yêu cầu phân tích theo AOAC. Phương pháp có thể áp dụng để phân tích các mẫu TPBVSK trên trị trường.

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CNPq
Os carotenóides são substâncias naturais que podem ser sintetizados por plantas e microorganismos. Recentemente houve um aumento do interesse da produção de corantes naturais por processos biotecnológicos de fontes biológicas devido à preocupação com o uso de aditivos químicos nos alimentos. A astaxantina é um dos principais carotenóides amplamente utilizado na indústria e na aquicultura, além disso, possui um importante papel na diminuição do risco de várias doenças degenerativas devido ao seu alto poder antioxidante. Neste trabalho foi estudada a produção de astaxantina por Mucor circinelloides utilizando o meio definido Hesseltine e Anderson e o resíduo agroindustrial melaço de cana-de-açúcar, nas concentrações de 4%, 7% e 10% na presença e ausência de LED´s azul. O inóculo foi obtido a partir do M. circinelloides após 5 dias de crescimento no meio BDA (Batata-Dextrose-Ágar), a 28ºC, 96 horas, 120 rpm. Após a seleção da melhor concentração os frascos contendo melaço de cana-de-açúcar foram incubados em shaker orbital sob diferentes temperaturas (25, 30 e 35ºC), pH (6,0, 7,0 e 8,0) e agitação (120, 135 e 150 rpm) por 96h sob iluminação com LED´S de cor azul e no escuro, segundo um planejamento fatorial 23 com quatro repetições no ponto central. Após o processo fermentativo, a astaxantina foi extraída da biomassa, utilizando uma solução de dimetilsulfóxido/acetona. Em seguida foi pré-purificada em éter de petróleo e analisada por espectrofotometria UV-visível (474 nm). A partir do ponto maximizado do planejamento fatorial foi realizada a determinação do peso seco, pH, proteínas totais, assim como teste de toxicidade e de atividade antioxidante da astaxantina obtida. A produção de astaxantina utilizando o meio Hesseltine e Anderson apresentou rendimento de 142,0 μg/g sem influência de LED´s azul e 340,1 μg/g quando se utilizou LED´s azul, com um aumento da produção de aproximadamente 42%. A melhor condição para a produção de astaxantina com melaço de cana-de-açúcar deu-se na concentração de 4% na ausência (32,7 μg/g) e presença de LED´s azul (134,4 μg/g) durante 96h, 120 rpm a 25°C. De acordo com o planejamento fatorial 23 o ponto máximo de produção foi obtido a 30°C, pH 7,5 e 100 rpm com cerca de 469,0 μg/g na ausência de LED´s azul e 667,6 μg/g na presença de LED´s azul, aumentando em aproximadamente 89% a produção. A astaxantina obtida por M. circinelloides apresentou baixa toxicidade frente à Artemia salina na concentração de 25% e potencial de inibição dos radicais livres de cerca de 92% nos índices testados. O resíduo agroindustrial melaço de cana-de-açúcar possui potencial para a produção de astaxantina por M. circinelloides principalmente na concentração de 4%. Os resultados apresentados demonstram que a utilização de LED´S azul pode aumentar significativamente o teor de astaxantina produzida pelo M. circinelloides.

Photosynthetic organisms can use solar energy to produce organic biomass starting from simple elements as CO2 and water, releasing oxygen as side product. Algae are characterized by high growth rate, extremely rapid life cycle and intrinsic high photosynthetic efficiency. Moreover, microalgae can also be cultivated in a mixed autotrophic/heterotrophic condition, using reduced carbon sources. Several algal strains are characterized by high lipid accumulation or production of high value compounds. Thus, algae not only represent a valid alternative to plants, but they also play a central role considering the sustainability related to their cultivation. Wastewaters and flue gas can be used to ensure nutrients and CO2 for carbon fixation, and, after biomass harvesting, water can be reused leading to a far lower consumption with respect to plants (especially in closed photobioreactor in which the evaporation is low). Unfortunately, algae evolved in conditions extremely different compared to actual industrial ones which involves 24/24 hours of high irradiance, strong shaking as well as high CO2 concentration: all these elements ensure high photosynthetic rate and thus high biomass accumulation but make necessary a domestication of strains. Since this need became evident, engineers, biologists and biotechnologists had tried to overcome algae cultivation limitations in order to became it feasible and economically useful. From a biotechnological point of view several targets could be pointed. Optimization of absorption/dissipation of light energy is one of the most interesting and explored. This thesis reports the use of several approaches to investigate the heat dissipation mechanisms (NPQ) in green algae, mainly focusing on the model organism Chlamydomonas reinhardtii. The results obtained reveal the molecular mechanisms of energy conversion from excitation energy into heat by the activity of specific pigment binding proteins called LHCSR (Light Harvesting Stress Related), going deep into details of the protein domains and pigments involved in the quenching process and the protein interaction network necessary for NPQ. In particular, the regulation of the accumulation of LHCSR proteins in Chlamydomonas reinhardtii revealed to be a successful genetic engineering strategy to improve biomass productivity. Among the possible application of microalgae, one of the most promising one is their use as green factories to produce high value products: here, we report the metabolic engineering of Chlamydomonas reinhardtii as a bio-factory for ketocarotenoids production. The use of microalgae as host to produce high value metabolites, represents, indeed, an effective way to break down costs related to their cultivation with a potential high impact into the market. Astaxanthin is, currently, produce using Haematococcus. lacustris (recently renamed from Haematococcus pluvialis) in which, its accumulation causes a stop in growth. For that reason, in this thesis effects of astaxanthin accumulation of H. lacustris was investigated. This thesis presents, with different approaches, a leap forward in microalgae domestication both trough enrichment of knowledge about NPQ and trough application of metabolic engineering to develop green bio-factories.