Department of Bioprocess Development, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications (SRTA-City), New Borg El‑Arab City, 21934, Alexandria, Egypt.
Department of Biology, College of Sciences and Arts Khulis, University of Jeddah, Jeddah, Saudi Arabia.
Sci Rep. 2022 May 3;12(1):7156. doi: 10.1038/s41598-022-11069-z.
Microalgae are a diverse group of microorganisms, the majority of which are photosynthetic in nature. Microalgae have different applications, the most important of which is the biological treatment of wastewater. Microalgae grow in various types of wastewater, such as wastewater polluted by Azo dyes, due to microalgae using wastewater as a culture medium, which contains many nutrients like nitrogen, phosphate, and carbon sources. Microalgae grow in various types of wastewater, such as wastewater polluted by Azo dyes, due to microalgae using wastewater as a culture medium, which contains many nutrients like nitrogen, phosphate, and carbon sources. So, microalgae are used for bioremediation of wastewater due to the efficiency of growing in wastewater and for the high production of lipids followed by trans-esterification to biodiesel. Face-centered central composite design (FCCCD) was used to determine the factors that have the most significant impact on the simultaneous decolorization of methyl red and lipid production by the fresh green alga Scenedesmus obliquus. The predicted results indicated that the alga decolorized 70.15% methyl red and produced 20.91% lipids by using 1 g/L nitrogen, an incubation time of 10 days, a pH of 8, and the concentration of methyl red is 17.65 mg/L. The dry biomasses of S. obliquus were also examined by SEM and FTIR before and after treatment with methyl red. SEM and FTIR showed that the properties of dry S. obliquus were altered after the biosorption of methyl red. According to GC-MS analysis of hexane extracts of S. obliquus, the lipid profile differed before and after methyl red decolorization. The results proved that it is possible to use S. obliquus to remove dyes and produce renewable fuels such as biodiesel. The novelty of this study is that this is the first time in which the effect of nitrogen concentrations in the medium used for algal growth on the removal of dye has been studied.
微藻是一类多样化的微生物，其中大多数具有光合作用。微藻有不同的应用，其中最重要的是生物处理废水。微藻在各种类型的废水中生长，如偶氮染料污染的废水，因为微藻将废水用作培养基，其中含有许多营养物质，如氮、磷和碳源。微藻在各种类型的废水中生长，如偶氮染料污染的废水，因为微藻将废水用作培养基，其中含有许多营养物质，如氮、磷和碳源。因此，由于微藻在废水中生长的效率以及随后通过酯交换转化为生物柴油的高脂质产量，微藻被用于废水的生物修复。采用中心复合面设计（FCCCD）确定对新鲜绿藻斜生栅藻同时脱色和产脂影响最大的因素。预测结果表明，在 1 g/L 氮、10 天培养时间、pH 值为 8 和甲基红浓度为 17.65 mg/L 的条件下，该藻可将 70.15%的甲基红脱色，并产生 20.91%的脂质。还通过 SEM 和 FTIR 检查了处理甲基红前后斜生栅藻的干生物量。SEM 和 FTIR 表明，在甲基红的生物吸附后，干斜生栅藻的性质发生了变化。根据 S. obliquus 中己烷提取物的 GC-MS 分析，甲基红脱色前后的脂质谱不同。结果证明，使用斜生栅藻去除染料并生产可再生燃料（如生物柴油）是可行的。本研究的新颖之处在于，这是首次研究用于藻类生长的培养基中的氮浓度对染料去除的影响。
