Objective

In this study, the isolation and identification of Exopolysaccharide (EPS) producing bacteria from polluted soil samples and its in vitro antioxidant activities were investigated.

Methods

Isolation and identification of bacteria was investigating using 16 s rDNA genome sequencing method. Further, optimization (pH, time, and temperature), purification and characterization of EPS were performed using different (UV, FT-IR, C¹³-NMR and H¹-NMR) methods. In addition, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide (H₂O₂) scavenging activities of EPS were performed.

Results

The molecular characterization of isolated strain was confirmed as Bacillus aerophilus by 16S rDNA sequencing. The sequence was submitted to NCBI (Genbank accession number MH553072). Characterization of EPS by UV, FT-IR, C¹³-NMR and H¹-NMR revealed the presence of hydroxyl, carbonyl, and carboxyl functional groups. SEM analysis of EPS showed a solid surface with an irregular shape. The optimum conditions for EPS production were pH 7.0, cultivation time 72 h (3.73 ± 0.211 g/L) and temperature 30 °C respectively. The yeast and sucrose extract showed higher EPS production. In addition, in vitro DPPH, H₂O₂ studies showed 56.6 and 67.5% of scavenging activity at 4 mg/mL of concentration.

Conclusions

From this study, the novel EPS producing Bacillus aerophilus rk1 was identified. Further, the purified EPS showed good antioxidant activity.

中文翻译：

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嗜气杆菌rk1胞外多糖的优化表征及其体外抗氧化活性

客观的

在这项研究中，研究了从污染土壤样品中分离和鉴定胞外多糖 (EPS) 细菌及其体外抗氧化活性。

方法

细菌的分离鉴定采用16s rDNA基因组测序法进行研究。此外，EPS 的优化（pH、时间和温度）、纯化和表征使用不同的（UV、FT-IR、C ¹³ -NMR 和 H ¹ -NMR）方法进行。此外，还进行了 EPS 的2, 2-diphenyl-1-picrylhydrazyl (DPPH) 和过氧化氢 (H ₂ O ₂ ) 清除活性。

结果

通过16S rDNA测序，分离菌株的分子特征被确认为嗜气芽孢杆菌。该序列已提交给 NCBI（Genbank 登录号 MH553072）。通过 UV、FT-IR、C ¹³ -NMR 和 H ¹ -NMR表征 EPS表明存在羟基、羰基和羧基官能团。EPS 的 SEM 分析显示出具有不规则形状的固体表面。生产EPS的最佳条件分别是pH 7.0，培养时间72 h（3.73±0.211 g / L）和温度30°C。酵母和蔗糖提取物显示出更高的 EPS 产量。此外，体外DPPH、H ₂ O ₂研究显示在 4 mg/mL 浓度下清除活性为 56.6% 和 67.5%。

结论

从这项研究中，鉴定了新的 EPS 产气芽孢杆菌 rk1。此外，纯化的 EPS 显示出良好的抗氧化活性。