Bouyam Somruethai, Choorit Wanna, Sirisansaneeyakul Sarote, Chisti Yusuf
Biotechnology Program, School of Agricultural Technology, Walailak University, Nakhon, Si Thammarat, 80161, Thailand.
Biomass and Oil Palm Center of Excellence, Walailak University, Nakhon, Si Thammarat, 80161, Thailand.
Biotechnol Prog. 2017 Nov;33(6):1589-1600. doi: 10.1002/btpr.2518. Epub 2017 Jul 6.
The green microalga Chlorella sp. TISTR 8990 was grown heterotrophically in the dark using various concentrations of a basal glucose medium with a carbon-to-nitrogen mass ratio of 29:1. The final biomass concentration and the rate of growth were highest in the fivefold concentrated basal glucose medium (25 g L glucose, 2.5 g L KNO ) in batch operations. Improving oxygen transfer in the culture by increasing the agitation rate and decreasing the culture volume in 500-mL shake flasks improved growth and glucose utilization. A maximum biomass concentration of nearly 12 g L was obtained within 4 days at 300 rpm, 30°C, with a glucose utilization of nearly 76% in batch culture. The total fatty acid (TFA) content of the biomass and the TFA productivity were 102 mg g and 305 mg L day , respectively. A repeated fed-batch culture with four cycles of feeding with the fivefold concentrated medium in a 3-L bioreactor was evaluated for biomass production. The total culture period was 11 days. A maximum biomass concentration of nearly 26 g L was obtained with a TFA productivity of 223 mg L day . The final biomass contained (w/w) 13.5% lipids, 20.8% protein and 17.2% starch. Of the fatty acids produced, 52% (w/w) were saturated, 41% were monounsaturated and 7% were polyunsaturated (PUFA). A low content of PUFA in TFA feedstock is required for producing high quality biodiesel. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1589-1600, 2017.
绿色微藻小球藻（Chlorella sp. TISTR 8990）在黑暗中进行异养生长，使用不同浓度的基础葡萄糖培养基，碳氮质量比为29:1。在分批操作中，五倍浓缩的基础葡萄糖培养基（25 g/L葡萄糖，2.5 g/L硝酸钾）中最终生物量浓度和生长速率最高。通过提高搅拌速率和减少500 mL摇瓶中的培养体积来改善培养物中的氧气传递，可提高生长和葡萄糖利用率。在300 rpm、30°C条件下，分批培养4天内可获得接近12 g/L的最大生物量浓度，葡萄糖利用率接近76%。生物量的总脂肪酸（TFA）含量和TFA生产率分别为102 mg/g和305 mg/(L·天)。在3 L生物反应器中，对使用五倍浓缩培养基进行四个循环补料的重复补料分批培养进行了生物量生产评估。总培养期为11天。获得了接近26 g/L的最大生物量浓度，TFA生产率为223 mg/(L·天)。最终生物量含有（重量/重量）13.5%的脂质、20.8%的蛋白质和17.2%的淀粉。所产生的脂肪酸中，52%（重量/重量）为饱和脂肪酸，41%为单不饱和脂肪酸，7%为多不饱和脂肪酸（PUFA）。生产高质量生物柴油需要TFA原料中PUFA含量较低。© 2017美国化学工程师学会生物技术进展，33:1589 - 1600，2017。
