破壺囊藻之饋料培養

Abstract

Thraustochytrium sp. FJ-01具有生合成蝦紅素及β胡蘿蔔素的能力，但目前較少以發酵槽培養破壺囊藻生產蝦紅素的報導。本研究經最適化探討，適合蝦紅素生產之培養基組成為20.00 g/L葡萄糖、1.33 g/L蛋白腖、1.33 g/L酵母抽出物，1/2海水濃度。於搖瓶批次培養中第4天細胞密度達5.13 g/L ，第5天β胡蘿蔔素濃度為17.52 mg/L，第6天蝦紅素濃度21.30 mg/L，並分別達到細胞乾重的0.45 %及0.93 %。FJ-01之蝦紅素濃度最佳對碳收率 (rate of glucose utilisation for the yield of astaxanthin)，為培養基濃度介於上述培養基的1-2倍濃度之間。在10天發酵槽批次培養中，第4天細胞密度達6.25 g/L，並發現第10天其蝦紅素產量達14.52 mg/L，占細胞乾重0.43 %。於發酵槽配合多次脈衝式饋料 (multi-pulse fed-batch) 策略中經16天培養，可有效將細胞密度提升3倍達19.8 g/L，蝦紅素濃度達至54.18 mg/L (占細胞乾重的0.28 % )、β胡蘿蔔素濃度達63.72 mg/L (占細胞乾重的 0.32 % )。於發酵槽連續式饋料培養中，在維持整個培養過程中粗脂肪產量占細胞乾重的70 % 以上的前提之下，進一步將蝦紅素日產量 (daily productivity) 由多次脈衝式饋料的3.70 mg/L/day 提升至7.80 mg/L/day。

Thraustochytrium sp. FJ-01 can synthesize and accumulate astaxanthin and β-carotene. However, there are few research about how to mass production of astaxanthin by Thraustochytrium sp.. After medium optimization, the optimized medium for astaxanthin production contains 20.0 g glucose, 1.33 g peptone, 1.33 g yeast extract per liter of half salt concentration seawater, which produced a biomass of 5.13 g/L after 4 days, and yielded β-carotene 17.52 mg/L (about 0.45 % of dry cell weight) after 5 days and astaxanthin at 21.30 mg/L (about 0.93 % of dry cell weight) after 6 days in Hinton’s flask. The most efficient rate of glucose utilization for the yield of astaxanthin in FJ-01 is 1 and 2 times the concentration of the medium which been mentioned above. Batch culture in fermentor with the optimized medium, which produced a biomass of 6.25 g/L at fourth day and we found the production of astaxanthin increased stably to 14.52 mg/L (about 0.43 % of biomass) after 10 days. In the multi-pulsed fed-batch in fermentors, three-times the biomass to 19.8 g/L and the production and cell content of astaxanthin and β-carotene reached 55.13 mg/L (0.28 %) and 63.72 mg/L (0.32 %) respectively in 16 days culture. In continuous fed-batch culture (in fermentor) we not only kept the crude lipid cell content above 70 % of cell dry weight in the whole culture period but also increased the daily productivity of astaxanthin from 3.70 mg/L/day (in multi-pulse fed-batch culture) to 7.80 mg/L/day.