Abstract

Leuconostoc pseudomesenteroides belongs to a group of lactic acid bacteria normally isolated from fruits, which has the capacity to produce exopolysaccharides (EPS). The present study aimed to optimize the EPS production of L. pseudomesenteroides JF17, isolated from juçara fruits (palm trees threatened with extinction in the Atlantic Forest), using the response surface methodology (RSM), besides evaluating the fermentation kinetics. The maximum production of EPS 53.77 mg/mL was obtained under ideal conditions of MRS broth supplemented with sucrose at 18%, w/v, fermentation temperature of 20 °C and initial pH of 7.30. The Luedeking-Piret model suggested that the production of EPS by the JF17 strain appeared to be associated with the cell growth of the microorganism, in addition to having high efficiency in the production of the polysaccharide from the substrate (Y_p/s = 17.85 ± 0.74 mg EPS/log CFU ). Thus, the ideal optimization conditions and kinetic parameters can be useful for increasing the scale up of the fermentation process in the industrial production of EPS by L. pseudomesenteroides JF17.

摘要

Leuconostoc pseudomesenteroides属于一组通常从水果中分离出来的乳酸菌，具有产生胞外多糖 (EPS) 的能力。本研究旨在优化L. pseudomesenteroides的 EPS 生产JF17，使用响应面法 (RSM) 从 juçara 果实（大西洋森林濒临灭绝的棕榈树）中分离出来，此外还评估了发酵动力学。在添加 18% w/v 蔗糖的 MRS 肉汤的理想条件下，EPS 的最大产量为 53.77 mg/mL，发酵温度为 20 °C，初始 pH 为 7.30。Luedeking-Piret 模型表明 JF17 菌株生产 EPS 似乎与微生物的细胞生长有关，此外在从底物生产多糖方面具有高效率 ( Y _p/s= 17.85 ± 0.74 mg EPS/log CFU）。因此，理想的优化条件和动力学参数可用于提高L. pseudomesenteroides JF17 工业生产 EPS 的发酵过程规模。