PRODUCTION OF TETRAPYRROLE COENZYMES BY A METHANOGEN

产甲烷菌，巴氏甲烷八叠球菌含有三个四吡咯，即，5<430>-氨基乙酰丙酸（ALA）生物合成的含铁细胞色素（亚铁血红素）、含镍因子F_（1-x）和类可啉化合物。在这项工作中，这些四吡咯和ALA，一个有效的除草剂的选择性形成进行。主要研究结果如下：1.在分批培养中考察了Co^&lt;2+&gt;、Ni^&lt;2+&gt;、Fe^&lt;2+&gt;对四吡咯选择性合成的影响。固定低浓度Ni^2+和F^2+的培养液中Co^2+的增加显著刺激胞外类咕啉的合成，而F ^2+<430>和血红素几乎保持不变。在<430>培养液中，随着Ni^2+或Fe^2+浓度的增加，细胞外F_或血红素的合成也有类似的刺激作用，这表明这三种四吡咯的合成可能受到相应金属的调节。然后，连续生产四吡咯 ...更多信息 在固定床反应器（载体：多孔粘土）中以10.1天的稀释率进行<-1>。从反应器顶部排出的废水中含有四吡咯，其浓度取决于进料介质中的Co^2+、Ni^2+、Fe^2+。最大产量（1-1碱基）分别为52 m [corrinoids]/d，24 m[F_<430>]/d和8 m [heme]/d.为了将ALA积累到培养基中，测试了一些ALA类似物作为ALA脱氢酶的抑制剂。结果表明，乙酰丙酸和4，6-二氧代庚酸均可促进ALA的积累，且后者在较低浓度下效果更好。发现2-酮戊二酸作为前体反应形成ALA，表明与对照实验相比，加入30 mM 2-酮戊二酸，ALA产量从37 mM增加83 mM。在固定床反应器中进行了以甲醇为原料连续生产ALA的试验，最大生产速率为400 m3/d。少

A methanogen, Methanosarcina barkeri contains three tetrapyrroles, i.e., Cocontaining corrinoids, Ni-containing factor F_<430> and Fe-containing cytochroms (hemes) which are biosynthesized via 5-aminolevulinic acid(ALA). In this work, the selective formation of these tetrapyrroles and ALA, a potent herbicide were carried out. The results obtained were as follows.1. Effects of Co^<2+>, Ni^<2+>, Fe^<2+> on the selective synthesis of respective tetrapyrroels were examined in batch culture. The increase of Co^<2+> in the medium fixing the low concentrations of Ni^<2+> and F^<2+> in the medium significantly stimulated the extracellular corrinoids syntheses, while F_<430> and heme were kept almost unchanged. Similar stimulative synthesis of extracellular F_<430> or heme was observed as a function of increasing Ni^<2+> or Fe^<2+> in the medium suggesting that the syntheses of these three tetrapyrroles might be regulated with the respective matal. Then, continuous production of tetrapyrroles i … More n a fixed-bed reactor(supporter: porous diatomaceous clay) was carried out a a dilution rate, 10.1 day^<-1>. The effluent discharged from the top of reactor contained the excreted tetrapyrroles whose concentration was depended upon Co^<2+>, Ni^<2+>, Fe^<2+> in the feed medium. The maximum productivies from the roactor(1-1 bases) were 52 m [corrinoids]/day, 24 m[F_<430>]/day and 8 m [heme]/day.2. To accumulate ALA into the culture medium, some ALA analogues were tested as inhibitor of ALA dehydratase. It was found that ALA was accumulated when levulinic acid or 4,6-dioxoheptanoic acid was added, the latted was more effective even at a much lower concentration. It was found that 2-oxoglutarate reacted as a precursor on the formation of ALA indicating that the production ALA increased 83 m from 37 m with the addition of 30 mM of 2-oxoglutarate compared with the control experiment. The continuous productions of ALA from methanol in fixed-bed reactors was tested indicating that the maximum production rate was 400 m/day. Less