Microbial Biotechnology Department, Institute of Biotechnology Research, National Research Centre, El-Tahreer Street, Dokki, Cairo, Egypt.
Microbiology Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
BMC Microbiol. 2023 Nov 22;23(1):361. doi: 10.1186/s12866-023-03117-z.
In investigating of (exopolysaccharide) EPS from unconventional sources, lactic acid bacteria have a vital role due to their generally recognized as safe (GRAS) status. EPSs have diverse applications such as drug delivery, antimicrobial activity, surgical implants, and many more in many sectors. Despite being important, the main hindrance to the commercial application of these significant biopolymers is low productivity. Therefore, this study primarily focuses on optimizing physio-chemical conditions to maximize the previously produced EPS from probiotic Lactiplantibacillus plantarum RO30 (L. plantarum RO30) using one factor at a time (OFAT) and method Response Surface Methodology (RSM).
The EPS obtained from L. plantarum RO30 named REPS. The medium formulation for REPS production using the OFAT method revealed that sucrose (20 g/L, beef extract (25 g/L), and ammonium sulfate at 4 g/L concentration were the optimum carbon, organic and inorganic nitrogen sources, and REPS yield was increased up to 9.11 ± 0.51 g/L. RSM experiments revealed that, a greatly significant quadratic polynomial attained from the Central Composite Design (CCD) model was fruitful for specifying the most favorable cultural conditions that have significant consequences on REPS yield. The maximal amount of REPS (10.32 g/L) was formed by: sucrose (40 g/L), beef extract (25 g/L), pH (5.5), incubation temperature (30 °C), and incubation period (72 h). A high closeness was obtained between the predicted and experimental values and it displayed the efficiency of the RSM.
This study was conducted to reinforce REPS production in the probiotic LAB L. plantarum RO30 by utilizing various experimental parameters. The maximum REPS yield of 10.32 g/L was attained under the circumstances optimized in the study.
在研究非常规来源的（胞外多糖）EPS 时，由于其公认的安全（GRAS）地位，乳酸菌起着至关重要的作用。EPS 在许多领域有多种应用，如药物输送、抗菌活性、手术植入物等。尽管这些重要的生物聚合物非常重要，但它们商业应用的主要障碍是产量低。因此，本研究主要侧重于通过单因素实验（OFAT）和响应面法（RSM）优化生理化学条件，以最大限度地提高先前从益生菌植物乳杆菌 RO30（L. plantarum RO30）中生产的 EPS。
从 L. plantarum RO30 中获得的 EPS 命名为 REPS。使用 OFAT 方法确定的 REPS 生产培养基配方表明，蔗糖（20 g/L）、牛肉提取物（25 g/L）和硫酸铵（4 g/L）分别是最佳的碳、有机和无机氮源，REPS 产量提高到 9.11 ± 0.51 g/L。RSM 实验表明，从中心组合设计（CCD）模型获得的非常显著的二次多项式对指定对 REPS 产量有重大影响的最有利的培养条件是有效的。通过以下方式形成最大量的 REPS（10.32 g/L）：蔗糖（40 g/L）、牛肉提取物（25 g/L）、pH（5.5）、培养温度（30°C）和培养时间（72 h）。预测值和实验值之间具有很高的接近度，显示了 RSM 的效率。
本研究旨在通过利用各种实验参数来增强益生菌 LAB 植物乳杆菌 RO30 中的 REPS 生产。在本研究优化的条件下，REPS 的最大产量达到 10.32 g/L。
