Hasanin Mohamed S, Abdella Mohamed A A
Cellulose and Paper Department, National Research Centre, Dokki, Giza, 12622, Egypt.
Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Institute, National Research Centre, Dokki, Giza, 12622, Egypt.
Microb Cell Fact. 2025 Aug 18;24(1):187. doi: 10.1186/s12934-025-02812-y.
Starch is a carbohydrate polymer, made up of multiple glucose units, connected through glycosidic bonds. Starch nanoparticles (StNPs) are characterized as particles that possess at least one dimension measuring less than 1000 nm, while still being larger than a single molecule, and they have several uses in diverse technological fields. Various studies indicate that synthesizing StNPs through physical and chemical techniques is expensive, requires a lot of energy, and may harm human health and the environment. In contrast, the enzymatic synthesis of StNPs exerts milder impacts on the final products, rendering them more eco-friendly, safe, and healthier. So, amylases can produce StNPs with enhanced solubility, gelation, and viscosity characteristics by hydrolyzing soluble starches.
This study explores the production of starch nanoparticles (StNPs) by α-amylase enzyme in situ from a newly isolated bacterial strain, which was biochemically described, genetically identified, and deposited into the database of GenBank under the designation Bacillus subtilis strain-MA6 (accession number: ON840082). The production medium was adjusted by employing statistical optimization of several parameters using the Plackett-Burman design (P-BD) and Box-Behnken design (B-BD) of the response surface methodology (RSM). Optimization of medium parameters using P-BD and B-BD models caused a 14.5-fold increase in α-amylase production. The StNPs were synthesized from bulk starch using three different α-amylase activities. Based on the B-BD results, trial 5 (B-BD/T), trial 7 (B-BD/T), and trial 13 (B-BD/T) were selected for the StNPs characterization using Fourier-transform infrared spectroscopy (FTIR), Dynamic light scattering (DLS), and high-resolution transmission electron microscopy (HR-TEM) analysis. Trial 13 represented the highest α-amylase activity and observed high stability with an average zeta potential of about - 15.1 ± 3.2 mV. Moreover, HR-TEM showed the StNPs as spheres with an average size of about 43 nm.
StNPs were synthesized from bulk starch using the B. subtilis strain-MA6 α-amylase enzyme. The concentration of α-amylase plays a role in converting bulk starch to nanosized particles, which affects the stability of the produced nanoparticles and their size. This observation offered an optimistic technique to produce StNPs via a green and eco-friendly process.
淀粉是一种碳水化合物聚合物，由多个葡萄糖单元通过糖苷键连接而成。淀粉纳米颗粒（StNPs）的特征是至少有一维尺寸小于1000纳米，同时仍大于单个分子，并且它们在不同的技术领域有多种用途。各种研究表明，通过物理和化学技术合成StNPs成本高昂，需要大量能源，并且可能危害人类健康和环境。相比之下，酶法合成StNPs对最终产品的影响更为温和，使其更环保、安全和健康。因此，淀粉酶可以通过水解可溶性淀粉来生产具有增强溶解性、凝胶化和粘度特性的StNPs。
本研究探索了一种新分离的细菌菌株原位产生的α-淀粉酶生产淀粉纳米颗粒（StNPs）的方法，该菌株经过生化描述、基因鉴定，并以枯草芽孢杆菌菌株-MA6（登录号：ON840082）的名称存入GenBank数据库。通过使用响应面法（RSM）的Plackett-Burman设计（P-BD）和Box-Behnken设计（B-BD）对几个参数进行统计优化来调整生产培养基。使用P-BD和B-BD模型对培养基参数进行优化，使α-淀粉酶产量提高了14.5倍。使用三种不同的α-淀粉酶活性从大量淀粉中合成了StNPs。根据B-BD结果，选择试验5（B-BD/T）、试验7（B-BD/T）和试验13（B-BD/T）使用傅里叶变换红外光谱（FTIR）、动态光散射（DLS）和高分辨率透射电子显微镜（HR-TEM）分析对StNPs进行表征。试验13表现出最高的α-淀粉酶活性，并观察到具有约-15.1±3.2 mV的平均zeta电位的高稳定性。此外，HR-TEM显示StNPs为平均尺寸约为43纳米的球体。
使用枯草芽孢杆菌菌株-MA6的α-淀粉酶从大量淀粉中合成了StNPs。α-淀粉酶的浓度在将大量淀粉转化为纳米颗粒的过程中起作用，这会影响所产生纳米颗粒的稳定性及其尺寸。这一观察结果提供了一种通过绿色环保工艺生产StNPs的乐观技术。
