Development of intelligent anaerobic fermentation process for reuse of carbon dioxide

Acetobacterium sp.是一种严格的厌氧菌，可以利用CO_2作为甲醇的共底物，在细胞内积累大量的维生素B1。因此，从理论上讲，从醋酸盐中生产出可用作化学原料的醋酸盐或甲烷是可能的。与维生素b_12一起用作燃料气体。本文的研究结果如下：1。在CO_2/甲醇的恒化连续培养条件下，醋酸杆菌的细胞（5 mg/g细胞）中维生素b_12含量很高，并以CO_2/甲醇为原料产生乙酸，即甲醇与CO_2的摩尔消耗比为2和1。随着稀释率的增加，维生素b__2和乙酸酯的比产率呈线性增加。基于此，为了提高乙酸和维生素Bin的产率，采用陶瓷材料填充的固定床生物反应器，以比生长速率高的稀释率运行，从而提高乙酸和细胞内维生素B_1_2.2的产率。研究了一种醋酸菌与甲烷原Methanosaeta concilii共培养醋酸转化为OH的方法。首先，建立了一个柔性床反应器，在反应器中填充聚丙烯/陶瓷混合物以粘附细胞。然后，由于产甲烷菌的生长速度比Acetobacterium低10倍，因此将该反应器与Acetobacterium的恒化培养物连接。采用该组合反应器工艺，使产甲烷菌消耗醋酸菌产生的乙酸，在0.15 h^-^1的高稀释率下，趋化菌培养中的乙酸几乎完全转化为甲烷，维生素b_2产率可达170 mg/盖，比醋酸菌分批培养的最大生长速率提高了约2倍。

A strict anaerobic acetogen, Acetobacterium sp. can utilize CO_2 as a co-substrate with methanol and accumulates high amount of vitamin B1 in the cells. Therefore, it is possible theoretically to produce acetate which is useful as chemical raw material or methane from the acetate which is. useful as fuel gas together with vitamin B_1_2.The results obtained in this work were as follows :1. In chemostat continuous culture on CO_2/methanol, Acetobacterium sp. had really high vitamin B_1_2 content in the cells (5 mg/g cell) and produced acetate almost stoichiometrically from CO_2/methanol, that is, the molar ratio of consumption of methanol and CO_2 was 2 and 1. And specific production rates of vitamin B_1_2 and acetate were increased linearly with increase of dilution rate. Based on this fact, to increase the production rates of acetate and vitamin Bin, a fixed bed bioreactor packed with ceramic material was operated at a high dilution rate than growth rate resulting high production rates of acetate and intracellular vitamin B_1_2.2. A nobel coculture of Acetobacterium with a metanogen, Methanosaeta concilii was developed to convert acetate to OH.First, a flxed bed reactor of M.concilii was set up, where polypropyrene/ceramic mixture was packed to adhere the cells. Then, this reactor was connected to a chemostat culture of Acetobacterium since the growth rate of the methanogen was 10 times lower than Acetobacterium.By using this combined reactor process where the methanogen cells consumed acetate produced by Acetobacterium, acetate in the chemostat culture was almost completely converted to methane and vitamin B_1_2 productivity increased up to 170 mg/lid at a high dilutions rate of 0.15 h^-^1, which is ca. 2 times higher than the maximum growth rate of Acetobacterium in batch culture.