Abstract: Effect of oxygen on the metabolism of Klebsiella pneumoniae was studied. The results indicated that 1,3-propanediol (PDO) could be produced under both aerobic and anaerobic conditions. As 4 h fermentation was carried out with initial glycerol concentration of 20 g/L, only 1.1 mmol/L PDO was produced in aerobic fermentation. However, PDO concentration reached 16 mmol/L under micro-aerobic condition，which was 1.28 fold to that of anaerobic condition. The activities of glycerol dehydrogenase, glycerol dehydratase and 1,3-propanediol oxidoreductase were 7.28, 1.14 and 0.52 U/mg protein respectively under micro-aerobic condition, which were higher than those under aerobic or anaerobic condition. The concentration of NADH (reduced B ? Nicotinamide Adenine Dinucleotide) was also affected by oxygen. It was 3.78 and 3.72 mmol/g (DCW) in anaerobic and micro-aerobic fermentations. However, it was only 0.85 mmol/g (DCW) when aerobic fermentation was applied.

Key words: Klebsiella pneumoniae, 3-propanediol, oxygen, metabolism

摘要： 考察了氧对Klebsiella pneumoniae发酵产1,3-丙二醇(PDO)代谢的影响. 研究结果表明，在厌氧或供氧条件下，K. pneumoniae都能利用甘油产PDO. 起始甘油浓度20 g/L，发酵时间4 h，在充分供氧条件下，PDO产量仅为1.1 mmol/L；但在微量供氧条件下，PDO产量为16 mmol/L，是厌氧发酵时的1.28倍. 在微量供氧条件下，调控PDO合成的关键酶甘油脱氢酶、甘油脱水酶及1,3-丙二醇氧化还原酶的活性分别为7.28, 1.14, 0.52 U/mg，高于厌氧或充分供氧条件下的相应酶活性. 氧对细胞内NADH的合成也有影响，厌氧及微量供氧条件下菌体内NADH含量分别为3.78及3.72 μmol/g (DCW)，高于充分供氧发酵时的0.85 μmol/g (DCW).

关键词: Klebsiella pneumoniae, 3-丙二醇, 氧, 代谢