超高压对植物乳杆菌能量代谢影响的研究

以植物乳杆菌ATCC8014为试材,研究超高压对其能量代谢的影响。建立了用氯化碘硝基四唑紫测定ATCC8014的INT代谢还原活性的比色法。用比色法测定了超高压对ATCC8014的INT代谢还原活性与葡萄糖利用的影响。试验结果表明,150~250MPa作用15min在MRS琼脂培养基上随着压力的增大菌落数显著降低,INT代谢还原活性降低显著,葡萄糖的利用变化不明显;超过300MPa后,葡萄糖的利用才显著降低;400MPa处理15min,尽管在MRS琼脂培养基上菌落数低于检测限,INT代谢还原活性为0%,而葡萄糖的利用能力仍为对照组的56.1%,超高压作用下ATCC8014的灭活与INT代谢还原活性的降低的相关性较好。说明ATCC8014的细胞膜上参与葡萄糖的吸收和运输的酶、糖酵解的酶与调节系统比三羧酸循环的酶与调节系统较耐压。三羧酸循环比糖酵解对超高压敏感,三羧酸循环的抑制是超高压灭活其的重要原因,这为了探讨超高压杀灭植物乳杆菌的机制提供了一定的理论依据。

Effects of high hydrostatic pressure on energy metabolism of Lactobacillus plantarum

Effects of high hydrostatic pressure on energy metabolism were investigated with Lactobacillus plantarum ATCC8014 as the test microorganism in this work.An INT colorimetric method of oxidation-reduction was established to measure INT metabolic activity of deoxidization of L.plantarum ATCC8014 cells.The utilization of glucose and INT metabolic activity of deoxidization of the cells after HPP treatment were determined using colorimetric methods.The experimental results showed that survival counts of ATCC8014 cells on MRS agar medium and INT metabolic activity of deoxidization decreased significantly,and little changes of utilization of glucose took place with increasing pressure ranging from 150 to 250 MPa for 15 min.Utilization of glucose also reduced evidently at high pressure(>300 MPa) for 15 min.Whereas survival cell counts on MRS agar medium were below the detection limit and INT metabolic activity of deoxidization of ATCC8014 was 0% after a 15-min pressure holding time at 400MPa,utilization of glucose of the cells retained 56.1% compared with that of untreated cells.In summary,it can be concluded that enzymes absorbing and transporting glucose in cellular membrane appear to have a high resistance to pressure,enzymes and biological regulating systems involved in glycolysis are more resistant to pressure than those in TCA(tricarboxylic acid cycle) system,TCA of ATCC8014 is more sensitive to pressure than glycolysis,and the decrease of INT metabolic activity of deoxidization is highly related to cell reduction during HHP,which provide some theoretical evidences for mechanisms of HHP sterilization.Inhibition of TCA metabolism is a very important cause of ATCC8014 inactivation by HHP.High hydrostatic pressure can be used as an effective tool to explore pathways of biological metabolism.