微藻是重要的可再生能源，由於它們在碳固定方面的高效率，微藻經常被用於生物燃料生產和蛋白質合成。通過結合多種生長因子，我們採用紫外線 (U.V.) 誘變來誘導微藻的基因組突變，從而提高脂質含量和蛋白質產量。另一方面，篩選過程廣泛且耗時，因此本研究旨在開發一種簡單的微流體技術，以增強微藻生物燃料和蛋白質合成。
本研究中我們使用低成本的電腦數值控制 (CNC) 微銑削技術而不是傳統的光刻方法製作懸滴微流控芯片，我們在每個芯片上的數十個單獨的懸滴（每個 0.3 L）中培養Botryococcus braunii（一種用於生物燃料生產的最常用的淡水微藻）和Cyanidium sp.（一種嗜酸藻類），並在每個芯片上監測它們的生長至少14 天，接下來我們使用不同大小的液滴來優化脂質含量，並首次證明了細胞密度對藻類生長和脂質生產的影響，最後我們在紫外線誘導的隨機突變後的原本位置測定了微藻的脂質和蛋白質含量，然後計算了適當的UV-C劑量，其中，各種光照被用來促進藻類生長、脂質和蛋白質的產生。
結果表明與在黑暗中培養的微藻相比，微藻被紫外線所修飾，生物量增長增加了137%及脂質含量增加了149%，與在光照條件下培養的微藻相比，微藻的脂質含量有所提高（23.8%）。以Cyanidium sp.為例，我們的結果表明，經過紫外線照射後發生突變的微藻中，生物量增長 (10.8%) 和蛋白質含量 (5%) 增加，並且在2500勒克斯下生長的藻類與在四種不同強度的光照下生長的微藻相比，其蛋白質含量 (35%) 增加。
總之，我們展示了新的方法來調整在特定芯片區域中調整四種不同照明的能力，並開發了一種用於長期微藻培養的懸滴式微流體系統，該系統可通過實驗室移液器輕鬆處理，無需額外的泵系統。最後，我們嘗試了拉曼光譜技術來確定我們感興趣的區域的不同拉曼位移（cm-1）峰，例如藻類蛋白質和脂質，Botryococcus braunii 和 Cyanidium sp。拉曼光譜顯示兩種藻類的峰強度存在差異菌株，顯示出較高的 Botryococcus braunii 脂質峰和較高的 Cyanidium sp 蛋白質峰。該微流體系統旨在促進微藻突變體的發展並用於提高藻類生產力。
關鍵詞：生物燃料；微流控；微藻；紫外線誘變

Microalgae are significant renewable energy sources. Due to their high efficiency in fixing carbon dioxide, microalgae are frequently employed for biofuel production and protein synthesis. By combining multiple growth factors, we employed ultraviolet (U.V.) mutagenesis to induce genome mutation in microalgae and thereby boost lipid content and protein production. On the other side, the screening process is extensive and time-consuming. This research sought to develop a straightforward microfluidic technology for enhancing microalgae biofuel and protein synthesis. We produced hanging-drop microfluidic chips using a low-cost computer numerical control (CNC) micro-milling technique rather than the conventional lithography method. We cultured Botryococcus braunii, one of the most commonly used freshwater microalgae for biofuel production, and cyanidium sp., an acidophilic algae, in tens of separate hanging drops (0.3 μL each) on each chip and monitored their growth for over 14 days in each drop. We used drops of varying sizes to optimize lipid content and demonstrated for the first time the influence of cell density on algal growth and lipid production. We determined the microalgae's lipid and protein content in situ following UV-induced random mutations and then computed the appropriate UV-C dosage. Additionally, various light illuminations were used to enhance algae growth, lipid and protein production.
When compared to microalgae cultivated in the dark, our data indicated that the microalgae modified with the desired U.V. procedure had a 137 percent increase in biomass growth and a 149 percent rise in lipid content. When compared to microalgae cultivated in the presence of light, our data indicated that the lipid content of our microalgae was enhanced (23.8 percent ).
In the case of Cyanidium sp., our results demonstrated increased biomass growth (10.8 percent) and protein content (5 percent) in microalgae mutated with the desired UV process, as well as increased protein content (35 percent) in algae grown at 2500 lux compared to microalgae grown in light at four different intensities. Additionally, we exhibited the capability of lighting an addressed chip region to be adjusted. In conclusion, we developed a hanging-drop microfluidic system for long-term microalgae cultivation that is easily handled with laboratory pipettes without the need for an extra pump system. Finally we tried raman spectroscopy technique to determine different raman shift(cm-1) peaks for our region of interest compunds like algal protein and lipids for both, Botryococcus braunii and Cyanidium sp .The raman spectrum shows difference in peak intensities in both of the algal strain,showing higher lipid peaks for Botryococcus braunii and higher protein peaks for Cyanidium sp .This microfluidic system is designed to facilitate the development of microalgae mutants and to be used to increase algal productivity.
Keywords: biofuel; microfluidic; microalgae; U.V. mutagenesis

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