Botany Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt.
Chemical Engineering and Pilot Plant Department, National Research Centre (NRC), El Buhouth St., Cairo, 12622, Dokki, Egypt.
Microb Cell Fact. 2023 Oct 6;22(1):202. doi: 10.1186/s12934-023-02216-w.
The application of exopolysaccharide-producing bacteria (EPS) in dual chamber microbial fuel cells (DCMFC) is critical which can minimize the chemical oxygen demand (COD) of molasses with bioelectricity production. Hence, our study aimed to evaluate the EPS production by the novel strain Bacillus piscis by using molasses waste. Therefore, statistical modeling was used to optimize the EPS production. Its structure was characterized by UV, FTIR, NMR, and monosaccharides compositions. Eventually, to highlight B. piscis' adaptability in energy applications, bioelectricity production by this organism was studied in the BCMFC fed by an optimized molasses medium.
B. piscis OK324045 characterized by 16S rRNA is a potent EPS-forming organism and yielded a 6.42-fold increase upon supplementation of molasses (5%), MgSO (0.05%), and inoculum size (4%). The novel exopolysaccharide produced by Bacillus sp. (EPS-BP5M) was confirmed by the structural analysis. The findings indicated that the MFC's maximum close circuit voltage (CCV) was 265 mV. The strain enhanced the performance of DCMFC achieving maximum power density (PD) of 31.98 mW m, COD removal rate of 90.91%, and color removal of 27.68%. Furthermore, cyclic voltammetry (CV) revealed that anodic biofilms may directly transfer electrons to anodes without the use of external redox mediators. Additionally, CV measurements made at various sweep scan rates to evaluate the kinetic studies showed that the electron charge transfer was irreversible. The SEM images showed the biofilm growth distributed over the electrode's surface.
This study offers a novel B. piscis strain for EPS-BP5M production, COD removal, decolorization, and electricity generation of the optimized molasses medium in MFCs. The biosynthesis of EPS-BP5M by a Bacillus piscis strain and its electrochemical activity has never been documented before. The approach adopted will provide significant benefits to sugar industries by generating bioelectricity using molasses as fuel and providing a viable way to improve molasses wastewater treatment.
在双室微生物燃料电池（DCMFC）中应用胞外多糖产生菌（EPS）至关重要，它可以用生物电能最小化糖蜜的化学需氧量（COD）。因此，我们的研究旨在评估新型菌株鱼类芽孢杆菌（Bacillus piscis）利用糖蜜废物生产 EPS 的情况。因此，使用统计建模来优化 EPS 的生产。通过 UV、FTIR、NMR 和单糖组成对其结构进行了表征。最后，为了突出 B. piscis 在能源应用中的适应性，研究了在优化的糖蜜培养基中为 BCMFC 供电时该生物的生物电能产生情况。
16S rRNA 鉴定的 B. piscis OK324045 是一种有效的 EPS 形成菌，在补充糖蜜（5%）、MgSO（0.05%）和接种量（4%）时，产量增加了 6.42 倍。新型芽孢杆菌产生的胞外多糖（EPS-BP5M）通过结构分析得到证实。结果表明，MFC 的最大闭路电压（CCV）为 265 mV。该菌株增强了 DCMFC 的性能，实现了 31.98 mW m 的最大功率密度（PD）、90.91%的 COD 去除率和 27.68%的脱色率。此外，循环伏安法（CV）表明，阳极生物膜可以直接将电子传递到阳极，而无需使用外部氧化还原介体。此外，在不同的扫描速率下进行 CV 测量以评估动力学研究表明，电子电荷转移是不可逆的。SEM 图像显示生物膜的生长分布在电极表面。
本研究为利用优化糖蜜培养基在 MFC 中生产 EPS-BP5M、去除 COD、脱色和发电提供了一种新型鱼类芽孢杆菌菌株。以前从未报道过鱼类芽孢杆菌菌株生产 EPS-BP5M 及其电化学活性。采用的方法将通过使用糖蜜作为燃料产生生物电能，并为改善糖蜜废水处理提供可行的方法，为糖业带来重大益处。
