Walisko Robert, Moench-Tegeder Judith, Blotenberg Jana, Wucherpfennig Thomas, Krull Rainer
Institute of Biochemical Engineering, Technische Universität Braunschweig, Gaußstraße 17, 38106, Braunschweig, Germany,
Adv Biochem Eng Biotechnol. 2015;149:1-27. doi: 10.1007/10_2015_322.
One of the most sensitive process characteristics in the cultivation of filamentous biological systems is their complex morphology. In submerged cultures, the observed macroscopic morphology of filamentous microorganisms varies from freely dispersed mycelium to dense spherical pellets consisting of a more or less dense, branched and partially intertwined network of hyphae. Recently, the freely dispersed mycelium form has been in high demand for submerged cultivation because this morphology enhances the growth and production of several valuable products. A distinct filamentous morphology and productivity are influenced by the environment and can be controlled by inoculum concentration, spore viability, pH value, cultivation temperature, dissolved oxygen concentration, medium composition, mechanical stress or process mode as well as through the addition of inorganic salts or microparticles, which provides the opportunity to tailor a filamentous morphology. The suitable morphology for a given bioprocess varies depending on the desired product. Therefore, the advantages and disadvantages of each morphological type should be carefully evaluated for every biological system. Because of the high industrial relevance of filamentous microorganisms, research in previous years has aimed at the development of tools and techniques to characterise their growth and obtain quantitative estimates of their morphological properties. The focus of this review is on current advances in the characterisation and control of filamentous morphology with a separation of eukaryotic and prokaryotic systems. Furthermore, recent strategies to tailor the morphology through classical biochemical process parameters, morphology and genetic engineering to optimise the productivity of these filamentous systems are discussed.
丝状生物系统培养过程中最敏感的过程特性之一是其复杂的形态。在深层培养中，观察到的丝状微生物的宏观形态各不相同，从自由分散的菌丝体到由或多或少密集、分支且部分交织的菌丝网络组成的致密球形颗粒。最近，自由分散的菌丝体形态在深层培养中需求很高，因为这种形态能提高几种有价值产品的生长和产量。独特的丝状形态和生产力受环境影响，可通过接种物浓度、孢子活力、pH值、培养温度、溶解氧浓度、培养基组成、机械应力或工艺模式以及添加无机盐或微粒来控制，这为定制丝状形态提供了机会。给定生物过程的合适形态因所需产品而异。因此，对于每个生物系统，都应仔细评估每种形态类型的优缺点。由于丝状微生物具有很高的工业相关性，过去几年的研究旨在开发工具和技术来表征其生长并获得其形态特性的定量估计。本综述的重点是在真核和原核系统分离的情况下，丝状形态表征和控制的当前进展。此外，还讨论了通过经典生化过程参数、形态学和基因工程来定制形态以优化这些丝状系统生产力的最新策略。
