Vitamin B_<12> production from a high effective methane fermentation system by CO_2 using acclimated-methogens

本研究从驯化产甲烷菌的发酵液中分离和定量了维生素B_(12)。在间歇进料底物气体(H_2/CO_2，80：20V/V)中，在pH为7，37℃的条件下，在停管中培养产甲烷菌。利用填充Amberlite XDA-2的离心管，尝试了一种新的维生素B_&lt；12&gt；分离方法。与以前的方法相比，使用该方法可以快速地分离维生素B和维生素12。在发酵液中检出高达110 mg/L以上的维生素B_(12)。对生产维生素B12的最佳铁钴比进行了研究，发现当铁钴比为0.2~0.6时，维生素B12的产量最高。以丝瓜为载体，采用产甲烷固定化反应器，在水力停留时间为6天时，发酵液中维生素B12的浓度为37.5 mg/L(图6)，比常规生产方法提高110-150倍。本研究表明，经CO_2/H_2驯化的产甲烷菌在生长过程中会向胞外发酵液中分泌Corrinoid，表明利用产甲烷菌培养系统连续生产胞外Corrinoid是可能的。

In this study, vitamin B_<12> was isolated and quantified from the culture broth of acclimated-methanogens. The methanogens were cultivated in the stopped tubes in the batch feed substrate gas (H_2/CO_2, 80 : 20v/v) at pH7 and 37℃. A novel isolation method for vitamin B_<12> was attempted using a centrifuge tube filled with Amberlite XDA-2. Using this method, the separation of vitamin B_<12> can be done quickly compared to previous techniques. A high concentration above 110mg/L of vitamin B_<12> in the culture broth was detected. For vitamin B12 production, the optimum Fe/Co ratio was investigated, we found that with the Fe/Co of 0.2-0.6, the maximum vitamin B12 was obtained. In the case of using methanogens fixed rector with the sponge gourd as carrier at HRT 6 days, we obtained the vitamin B12 concentration in culture broth as 37.5 mg/L (Fig.6), the productivity is 110-150 times higher than conventional production method. This investigation indicates that acclimated-methanogens using CO_2/H_2 excretes corrinoids into the extracellular culture broth during growth, and suggests that the continuous production of extracellular corrinoids using the methanogens cultivation system is possible.