Dueñas Maite, Munduate Arantza, Perea Aidé, Irastorza Ana
Departamento de Química Aplicada, Facultad de Ciencias Químicas, Box 1072, E-20080 San Sebastián, Spain.
Int J Food Microbiol. 2003 Oct 15;87(1-2):113-20. doi: 10.1016/s0168-1605(03)00060-6.
Ropy Pediococcus damnosus (strain 2.6) was used for production of exopolysaccharide (EPS) in a semidefined medium. From a kinetic point of view, an experiment conducted in SMD medium containing 30 g l(-1) glucose and 5 g l(-1) Bacto casamino acids (Difco Laboratories, Detroit, MI), without pH control, showed that EPS production took place mainly during the growth phase. The viscosity of the cultures developed in parallel to the EPS synthesis until 94 h of incubation; after 200 h of fermentation, viscosity decreased. The effect of glucose, Bacto casamino acid concentrations and temperature on growth and EPS production was determined by using a full factorial design. Within the domain of experimental conditions considered, the concentration of glucose and Bacto casamino acids has a significant effect on the production of exopolysaccharide. The incubation at 12 degrees C produced a prolonged lag phase and due to the lower growth yield, higher specific EPS production was found at this temperature. At 25 degrees C the EPS production was mainly enhanced by the increase in glucose concentration. The increase in nitrogen concentration from 5 to 15 g l(-1) did not yield greater EPS production. However, at 12 degrees C optimal EPS production was obtained when both higher glucose and nitrogen concentrations were used.
黏性有害片球菌（菌株2.6）用于在半限定培养基中生产胞外多糖（EPS）。从动力学角度来看，在含有30 g l⁻¹葡萄糖和5 g l⁻¹细菌用酪蛋白氨基酸（底特律迪福科实验室）的SMD培养基中进行的一项无pH控制实验表明，EPS生产主要发生在生长阶段。培养物的黏度与EPS合成同步发展，直至培养94小时；发酵200小时后，黏度下降。通过全因子设计确定了葡萄糖、细菌用酪蛋白氨基酸浓度和温度对生长及EPS生产的影响。在所考虑的实验条件范围内，葡萄糖和细菌用酪蛋白氨基酸的浓度对胞外多糖的生产有显著影响。在12℃下培养产生了较长的延迟期，并且由于生长产量较低，在此温度下发现了较高的特定EPS产量。在25℃时，EPS产量主要通过葡萄糖浓度的增加而提高。氮浓度从5 g l⁻¹增加到15 g l⁻¹并没有产生更高的EPS产量。然而，在12℃时，当同时使用较高的葡萄糖和氮浓度时可获得最佳的EPS产量。
