不同的培養裝置，對紫色桿菌素生產的效益評估

Evaluation of the Benefit of Different Devices for the Production of Violacein

天然色素種類繁多，除了顏色多樣，有些天然色素亦具有藥理活性。紫色桿菌素是紫色桿菌生產的疏水性色素，紫色桿菌素已被證明具有抗氧化、抗菌、以及抗腫瘤細胞等活性。本研究比較三角錐形瓶、凹槽三角錐形瓶、以及客製化的氣舉式圓柱管對紫色桿菌生產紫色桿菌素的影響。三角錐形瓶與凹槽三角錐形瓶放置於軌道搖床上搖晃培養，氣舉式圓柱管以小型打氣幫浦供氣進行培養。將紫色桿菌接種在 150 ml LB 液態培養基，分別倒入上述 3 種裝置中進行培養。在不同的培養時間點，取出菌液，使用乙酸乙酯萃取培養液中的紫色桿菌素，再將乙酸乙酯揮發去除，將含有紫色桿菌素的粉末溶解在乙醇中，利用分光光度計測量紫色桿菌素溶液的吸光值並推估其濃度。結果顯示，在培養 24 小時後，在標準三角錐形瓶、凹槽三角錐形瓶、以及氣舉式圓柱管中色桿菌素濃度分別為 86.3±1.0 µg/ml、66.6±2.3 µg/ml、115.3±2.1 µg/ml，延長培養時間至 72 小時，紫色桿菌素濃度分別 132.1±1.8 µg/ml、146.0±2.2 µg/ml、188.4±11.6 µg/ml。因此無論是在細菌的對數生長期或是穩定生長期，氣舉式圓柱管培養所獲得的紫色桿菌素濃度都是最高。相較於錐形瓶，氣舉式圓柱管的底面積小，因此在有限的實驗室空間內，可以佈建更多的氣舉式圓柱管，進行紫色桿菌素生產條件測試或是紫色桿菌素突變菌株的篩選研究。

Some natural pigments of various colors have pharmacological properties. Violacein is a hydrophobic pigment produced by Chromobacterium violaceum that has been reported to have antioxidant, antibacterial, and antitumor properties. This study compared the effects of conical flasks, triple-baffled flasks, and custom-made cylindrical airlift tubes on the production of violacein from C. violaceum. For culturing the bacteria, conical flasks and triple-baffled flasks were placed on an orbital shaker, and the cylindrical airlift tubes were connected to a small air pump. The bacteria culture was added to a conical flask, triple-baffled flask, and cylindrical airlift tube containing 150 mL LB liquid medium. At different time points during culturing, violacein in the bacterial culture was extracted using ethyl acetate, which was later removed using an evaporator. The violacein powder was collected and dissolved in ethanol. The violacein concentration was determined using UV–visible spectroscopy. After incubation for 24 h, the concentration of violacein in the conical flask, triple-baffled flask, and cylindrical airlift tube was 86.3 ± 1, 66.6 ± 2.3, and 115.3 ± 2.1 μg/mL, respectively; after incubation for 72 h, the concentration of violacein was 132.1 ± 1.8, 146.0 ± 2.2, and 188.4 ± 11.6 μg/mL, respectively. Therefore, regardless of whether the bacteria was in the logarithmic growth phase or stable growth phase, the concentration of violacein obtained using the cylindrical airlift tube was the highest among the three methods. Compared with the conical flask, the bottom area of the cylindrical airlift tube is small. Therefore, in the limited laboratory space, more cylindrical airlift tubes can be deployed to test the production conditions of violacein or search for mutant strains.