通气提高Klebsiella oxytoca HP1发酵产氢

研究了Klebsiella oxytoca HP1在不同通气条件下的生长和放氢特性．批式发酵实验结果表明：通氩气放氢效果最好，通二氧化碳放氢效果最差．提高氩气通气速率能显著提高产氢量。0．25L／Lmin条件下的产氢量达到1155mL是不通气时的2．41倍，但通气也影响延迟期的长短。氩气通量应该与微生物生长阶段相匹配．代谢产物分析表明：K．oxytoca HP1呈混合酸发酵特性，主要代谢产物有乙酸、乙醇、乳酸和2，3-丁二醇，氩气通气速率明显影响丙酮酸节点的代谢途径和通量，从高通气条件到不通气条件，代谢主要途径按乙酸途径→乙醇途径→乳酸途径的次序转变，通气速率是K．oxytoca HP1发酵产氢的重要调控因子．

Enhanced Hydrogen Production of Klebsiella oxytoca HP1 by Gas Bubbling in Liquid Phase

The effects of bubbling gas in culture liquid on growth and hydrogen production by K.oxytoca HP1 were studied in a series of glucose fermentation.Argon,nitrogen,hydrogen and carbon dioxide were chosen as tested gases,among which hydrogen and carbon dioxide are gas phase metabolites,and nitrogen used to test if the microbe has nitrogenase by compared hydrogen production yield with inert gas of argon.Results showed that the kind of bubble gas was the key factor of growth and hydrogen production.Argon was the best gas for K.oxytoca HP1 hydrogen producing,and CO_2 was the worst.From the results that argon's hydrogen production yield was larger than that of nitrogen,it seemed that K.oxytoca HP1 has nitrogenase and had activity under the conditions.Bubble rate was also key factor,at 0.25 L/L min high bubble rate of argon,the hydrogen yield reached 1 155 mL,2.41 times higher than that of no bubbling case.Bubble rate also influenced growth lag phase and hydrogen evolution time.Metabolite analysis showed that K.oxytoca HP1 has a property of mix acid fermentation,acetate,ethanol,lactate were the main metabolites.Bubble rate influenced pyruvate metabolic behavior.From high bubble to no bubble,the main metabolic pathway shifted from acetic acid to ethanol and then to lactate,bubble rate was the key factor regulating pyruvate metabolism.