摘要
克雷伯杆菌发酵生产1,3-丙二醇(1,3-PD)的过程中,通过加入表面活性剂可改善细胞通透性,以减少产物和副产物对细胞生长与代谢的抑制作用,从而促进细菌生长和1,3-PD产出.对比研究了吐温-80(Tween-80)、曲拉通X-100(Triton X-100)、壬基酚聚氧乙烯醚-10(OP-10)和十六烷基三甲基溴化铵(CTAB)等对发酵中甘油脱氢酶(GDH)、1,3-丙二醇氧化还原酶(PDOR)和甘油脱水酶(GDHt)等3种关键酶活的影响.实验表明OP-10能较好改善细胞通透性,胞内释放核酸浓度随添加OP-10量的增加有明显提高.低浓度的OP-10对GDH,PDOR活性及细胞生长有较好的促进作用;发酵8～12 h时添加1.0 g·L-1的OP-10可使1,3-PD浓度和摩尔转化率有较大提高.结合透射电镜发现非离子表面活性剂OP-10损伤膜结构,致细胞通透性改变,有利于充分发挥细胞内酶的催化活性,对细菌生长和1,3-丙二醇的合成有较大促进作用.
The growth and metabolic reactions were inhibited by product and by-products in Klebsiella pneumoniae fermentation from glycerol to 1,3-propanediol （1,3-PD）. The present study was focused on how cellular growth and permeability were enhanced through adding different surfactants in view of 1,3-PD yield. Various treatments with auxiliary agents, such as tween-80, triton X-100, OP-10 and CTAB and their impacts on the activities of glycerol dehydrogenase （GDH）, glycerol dehydratase （GDHt） and 1,3-PD oxidoreductase （PDOR） were investigated. It was demonstrated that the performances of OP-10 were dependent on the adding concentration and time, leading to enhancing the growth and permeability of the cell. An adequate amount of OP-10 ensured high activities of GDH and PDOR, and promoted the growth of bacterium. Optimized activity of the cells was manipulated with 1.0 g·L^-1 of OP-10 between 8- 12 h, associated with the final 1,3-propanediol concentration and molar yield increased greatly. It was also found that when treated with OP-10, the output of nucleic acid increased. From Microscopy image and TEM image of Klebsiella pneumoniae, the reason for the membrane permeability enhancement might be related to the ability of the nonionic surfactant OP-10 to partially damage the membrane structure. It is an effective way to improve enzyme activities, cell growth and 1,3-PD yield with regulation of cellular permeability.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2009年第18期2133-2138,共6页
Acta Chimica Sinica
关键词
克雷伯杆菌
细胞通透性
非离子表面活性剂
酶活
代谢调节
Klebsiella pneumoniae
cell permeability
nonionic surfactant
enzyme activity
metabolic regulation
