Filamentous fungi cultivated as biopellets are well established in biotechnology industries. A distinctive feature of filamentous fungi is that hyphal growth and fungal morphology affect product titers and require tailored process conditions. Within the pellet, mass transfer, substrate consumption, and biomass formation are intricately linked to the local hyphal fraction and pellet size. This study combined oxygen concentration measurements with microelectrode profiling and three‐dimensional X‐ray microtomography measurements of the same fungal pellets for the first time. This allowed for the precise correlation of micromorphological information with local oxygen concentrations of two Aspergillus niger strains (hyperbranching and regular branching). The generated results showed that the identified oxygen‐penetrated outer pellet regions exhibited a depth of 90–290 µm, strain‐specific, with the active part percentage in the pellet ranging from 18% to 69%, without any difference between strains. Using a 1D continuum diffusion consumption model, the oxygen concentration in the pellets was computed depending on the local hyphal fraction. The best simulation results were achieved by individually estimating the oxygen‐related biomass yield coefficient of the consumption term within each examined pellet, with an average estimated value of 1.95 (± 0.72) kg biomass per kg oxygen. The study lays the foundation for understanding oxygen supply in fungal pellets and optimizing processes and pellet morphologies accordingly.

中文翻译：

---

黑曲霉丝状颗粒中的耗氧量：微电极测量和建模


以生物颗粒形式培养的丝状真菌在生物技术行业中已得到广泛应用。丝状真菌的一个显着特征是菌丝生长和真菌形态会影响产品滴度，需要定制的工艺条件。在颗粒中，传质、底物消耗和生物质形成与局部菌丝部分和颗粒大小错综复杂地相关。这项研究首次将氧浓度测量与相同真菌颗粒的微电极分析和三维 X 射线显微断层扫描测量相结合。这允许将微形态学信息与两种黑曲霉菌株 （超分支和规则分支） 的局部氧浓度精确关联。生成的结果表明，鉴定出的氧渗透外颗粒区域表现出 90-290 μm 的深度，菌株特异性，颗粒中的活性部分百分比在 18% 到 69% 之间范围，菌株之间没有任何差异。使用 1D 连续介质扩散消耗模型，根据局部菌丝分数计算颗粒中的氧浓度。通过单独估计每个检查颗粒内消耗项的氧相关生物量产率系数，平均估计值为 1.95 （± 0.72） kg 生物量/kg 氧气，从而获得最佳模拟结果。该研究为了解真菌颗粒中的氧气供应并相应地优化工艺和颗粒形态奠定了基础。