School of Life Science and Biotechnology, Dalian University of Technology, Linggong Road 2, Dalian, 116024, China.
Bioprocess Biosyst Eng. 2018 Aug;41(8):1079-1088. doi: 10.1007/s00449-018-1937-9. Epub 2018 Apr 12.
Ionic liquids (ILs) as "green" solvents have been widely used owing to their excellent properties, e.g., for biodiesel production. Crude glycerol as a by-product in biodiesel production is an ideal feedstock for the microbial production of 1,3-propanediol (PDO), which is a versatile bulk chemical. PDO can be produced by microbial consortium with the advantages of high substrate tolerance and narrow by-product profile. In the present study, the effect of IL 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Emim][TfO]) was evaluated on the capacity of PDO production from crude glycerol by microbial consortium DL38-BH. In the batch fermentation at 60 g/L crude glycerol and 10 g/L [Emim][TfO], the concentration and yield of PDO from glycerol increased from 23.14 g/L and 0.45 mol/mol to 31.17 g/L and 0.60 mol/mol, respectively. Our results showed that [Emim][TfO] decreased the ratio of intracellular NADH to NAD and increased the concentration of 3-HPA during batch fermentation. The activities of three key enzymes in glycerol metabolism were stimulated by [Emim][TfO] during the batch fermentation by microbial consortium DL38-BH. Compared to the control, the proportion of Klebsiella genus which could convert glycerol to PDO increased significantly from 79.19% to 89.49% and the other genera that did not produce PDO were dramatically decreased (P < 0.05) at the end of batch fermentation. This work demonstrated that [Emim][TfO] significantly improved the concentration and yield of PDO from crude glycerol by adjusting microbial community during batch fermentation by microbial consortium.
离子液体（ILs）作为“绿色”溶剂，由于其优异的性质而被广泛应用，例如用于生物柴油生产。生物柴油生产中的粗甘油是微生物生产 1,3-丙二醇（PDO）的理想原料，PDO 是一种多功能大宗化学品。PDO 可以通过微生物联合体生产，具有高底物耐受性和窄副产物谱的优点。在本研究中，评估了离子液体 1-乙基-3-甲基咪唑三氟甲磺酸盐 ([Emim][TfO]) 对微生物联合体 DL38-BH 从粗甘油生产 PDO 的能力的影响。在 60 g/L 粗甘油和 10 g/L [Emim][TfO]的分批发酵中，甘油中 PDO 的浓度和产率从 23.14 g/L 和 0.45 mol/mol 分别增加到 31.17 g/L 和 0.60 mol/mol。我们的结果表明，[Emim][TfO]降低了分批发酵过程中细胞内 NADH 与 NAD 的比值，并增加了 3-HPA 的浓度。[Emim][TfO]在分批发酵过程中刺激了甘油代谢中三种关键酶的活性。与对照相比，能够将甘油转化为 PDO 的克雷伯氏菌属的比例从 79.19%显著增加到 89.49%，而不产生 PDO 的其他属则在分批发酵结束时显著减少（P<0.05）。这项工作表明，[Emim][TfO]通过调节微生物联合体在分批发酵过程中的微生物群落，显著提高了粗甘油中 PDO 的浓度和产率。
