Intensification of bioprocesses with filamentous microorganisms

Abstract

Many industrial biotechnological processes use filamentous microorganisms to produce platform chemicals, proteins, enzymes and natural products. Product formation is directly linked to their cellular morphology ranging from dispersed mycelia over loose clumps to compact pellets. Therefore, the adjustment and control of the filamentous cellular morphology pose major challenges for bioprocess engineering. Depending on the filamentous strain and desired product, optimal morphological shapes for achieving high product concentrations vary. However, there are currently no overarching strain- or product-related correlations to improve process understanding of filamentous production systems. The present book chapter summarizes the extensive work conducted in recent years in the field of improving product formation and thus intensifying biotechnological processes with filamentous microorganisms. The goal is to provide prospective scientists with an extensive overview of this scientifically diverse, highly interesting field of study. In the course of this, multiple examples and ideas shall facilitate the combination of their acquired expertise with promising areas of future research. Therefore, this overview describes the interdependence between filamentous cellular morphology and product formation. Moreover, the currently most frequently used experimental techniques for morphological structure elucidation will be discussed in detail. Developed strategies of morphology engineering to increase product formation by tailoring and controlling cellular morphology and thus to intensify processes with filamentous microorganisms will be comprehensively presented and discussed.

Morphology engineering for novel antibiotics: Effect of glass microparticles and soy lecithin on rebeccamycin production and cellular morphology of filamentous actinomycete Lentzea aerocolonigenes

“…For an investigation of the inner pellet structure, a pellet slicing technique ( Lin et al, 2010 ; Krull et al, 2013 ; Dinius et al, 2023 ) was applied to obtain pellet cross-sections. Initially, single pellets were isolated and located in the frozen section medium (Richard-Allan Scientific Neg-50 Frozen Section Medium, Thermo Fisher Scientific, Waltham, United States).…”

“…To attain the preferred morphology for enhanced product synthesis, various strategies have been developed in the past to address specific modifications (e.g., alteration of pellet size) regarding filamentous cellular morphology ( Driouch et al, 2012 ), generally termed morphology engineering ( Böl et al, 2021 ). Although classical methods pay attention to cultivation control on the process level (e.g., alteration of pH value or stirrer configurations) ( Krull et al, 2013 ), the latest strategies focus on the supplementation of additives or substances to the cultivation ( Böl et al, 2021 ; Dinius et al, 2023 ) to increase the product formation.…”