应用氧化还原电位调控拟干酪乳杆菌发酵产乳酸过程

Effect of Oxidoreduction Potential on Lactic Acid Production by Lactobacillus paracasei

DOI：10.3969/j.issn.1673-1689.2012.10.003

中文关键词: 拟干酪乳杆菌 氧化还原电位 乳酸 辅酶

英文关键词: Lactobacillus paracasei redox potential lactic acid cofactor

基金项目:国家973计划项目(2007CB714303)

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中文摘要:

在拟干酪乳杆菌分批发酵产乳酸过程中,通过自反馈的氧化还原电位控制系统改变通入空气和氮气的比例控制发酵液氧化还原电位(oxidation-reduction potential,ORP)于不同水平,研究了氧化还原电位对乳酸发酵过程中菌体生长和代谢的影响。较高的ORP(通入1.5 L/min空气、-100 mV、-150 mV)条件下的菌体浓度是较低ORP时的(-200 mV、-300 mV、通入1.5 L/min纯氮)2倍以上,且乳酸产量较高,但糖酸转化率较低。ORP为-100 mV时,乳酸产量最高,达到153.00 g/L;ORP为-200 mV时,糖酸转化率最高,为100.32%。最后分析了胞外ORP对胞内表征氧化还原状态的参数NADH/NAD+比值变化的影响,证实胞外ORP可通过影响胞内氧化还原状态,进而影响菌体代谢和乳酸合成,胞外ORP可作为乳酸发酵过程的有效调控参数。

英文摘要:

The aim of this research was to investigate the impact of extracellular oxidoreduction potential(ORP) on lactic acid production in batch culture by Lactobacillus paracasei.The ORP control was conducted by regulating the ratio of air flow rate to nitrogen flow rate in the inlet aeration of fermentor.As the results shown,the high ORP levels(the inlet air 1.5 L/min,-100mV,-150mV) resulted in higher lactic acid production but lower sugar-lactic acid conversion ratio,and the biomass was more than two times than that in the low ORP conditions(-200 mV,-300 mV,the inlet nitrogen 1.5 L/min).The highest lactic acid production(153 g/L) was obtained at the ORP level of-100 mV.The highest lactic acid yield(100.3%) was obtained at ORP level of-200 mV.Further more,the impact of ORP on the intracellular redox potential(NAD+/NADH) was investigated.

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