Guerra N P, Rua M L, Pastrana L
Departamento de Bioquímica Xenética e Inmunología, Facultade de Ciencias de Ourense, Universidade de Vigo, As Lagos, Spain.
Int J Food Microbiol. 2001 Nov 8;70(3):267-81. doi: 10.1016/s0168-1605(01)00551-7.
The ability of Lactococcus lactis subsp. lactis CECT 539 and Pediococcus acidilactici NRRL B-5627 to produce bacteriocins on both diluted and concentrated whey was investigated in batch fermentations. Both strains produced the higher amounts of biomass and bacteriocin titres on diluted whey. Luedeking and Piret expression was able to model the production of nisin, which was produced as a primary metabolite on both culture media. However, the pediocin production could not be typified in any case due to the negligible growth of P. acidilactici. Although the whey supported the growth and bacteriocin production by the two strains, both biomass and bacteriocin productions were lower than those obtained on MRS broth. The effect of total sugar, nitrogen, phosphorous and buffer concentrations on the production of nisin and pediocin was studied in diluted whey using factorial experiments and empirical modelling. The production of nisin was greatly inhibited by the increase in nitrogen, buffer, and to a lesser extent, sugar concentration in the medium, nevertheless, the used phosphorous source produced a light stimulatory effect on bacteriocin synthesis. In addition, the growth of Lc 1.04 was mainly affected by the nitrogen source used. On the other hand, pediocin was inhibited by the increase in buffer, phosphorous, and to a lesser degree, by the sugar and nitrogen concentration. The inhibitory activity of pediocin disappeared almost totally after 15 min of treatment with trypsin, papain, subtilisin and pepsin. The activity of nisin was drastically reduced by treatment with trypsin, subtilisin and pepsin. Nevertheless, 50% of the initial activity was retained when nisin was treated with papain. Both bacteriocins showed the highest heat stability at acidic pH and short incubation times.
在分批发酵中研究了乳酸乳球菌乳酸亚种CECT 539和嗜酸乳杆菌NRRL B - 5627在稀释乳清和浓缩乳清上产生细菌素的能力。两种菌株在稀释乳清上产生的生物量和细菌素滴度更高。Luedeking和Piret表达式能够模拟乳酸链球菌素的产生，乳酸链球菌素在两种培养基上均作为初级代谢产物产生。然而，由于嗜酸乳杆菌的生长可忽略不计，在任何情况下都无法确定片球菌素的产生类型。尽管乳清支持这两种菌株的生长和细菌素产生，但生物量和细菌素产量均低于在MRS肉汤上获得的产量。使用析因实验和经验模型研究了总糖、氮、磷和缓冲液浓度对稀释乳清中乳酸链球菌素和片球菌素产生的影响。培养基中氮、缓冲液的增加以及糖浓度的增加在较小程度上极大地抑制了乳酸链球菌素的产生，尽管如此，所用的磷源对细菌素合成产生了轻微的刺激作用。此外，Lc 1.04的生长主要受所用氮源的影响。另一方面，缓冲液、磷的增加以及糖和氮浓度在较小程度上抑制了片球菌素的产生。用胰蛋白酶、木瓜蛋白酶、枯草杆菌蛋白酶和胃蛋白酶处理15分钟后，片球菌素的抑制活性几乎完全消失。用胰蛋白酶、枯草杆菌蛋白酶和胃蛋白酶处理后，乳酸链球菌素的活性急剧降低。然而，用木瓜蛋白酶处理乳酸链球菌素时，保留了50%的初始活性。两种细菌素在酸性pH值和短孵育时间下均表现出最高的热稳定性。
