Influence of carbon source complexity on porosity, water retention and extracellular matrix composition ofNeurospora discretabiofilms

Abstract

Aims To evaluate carbon source complexity as a process lever to impact the microstructure, chemical composition and water retention capacity of biofilms produced by Neurospora discreta. Methods and Results Biofilms were produced by nonpathogenic fungus N. discreta, using sucrose, cellulose or lignin as carbon source. The increase in complexity of carbon source from sucrose to lignin resulted in decreased water retention values (WRV) and wet weights of harvested biofilms. Confocal laser scanning microscopy was used to calculate porosity from bright‐field images, and relative stained areas of cells and carbohydrates from fluorescence imaging of samples stained with Trypan blue and Alexa Fluor 488. Porosity and relative quantity of cells increased with increase in carbon source complexity while the amount of carbohydrates decreased. The chemical analysis of the extracted extracellular matrix (ECM) showed that biofilms grown on more complex carbon sources had lower carbohydrate and protein content, which also explains the lower WRV trend, as carbohydrates are hydrophilic. Conclusions The nature of carbon source impacts the metabolic pathway of cells, thereby influencing the relative proportions of ECM and cells. This in turn impacts the microstructure, composition and water content of biofilms. Significance and Impact of the Study This work shows that carbon source can be used as process lever to control the properties of biofilms and presents a novel view of biofilms as potentially useful biomaterials.

Advanced mycelium materials as potential self-growing biomedical scaffolds

“…Being able to greatly affect cell migration, oxygen regulation and nutrient exchange, porosity is a key parameter that should be considered during a scaffold design 61 . Usually, in tissue engineering applications, average pore size is measured by the post-processing of SEM micrographs, while total porosity can be calculated separately by liquid displacement method, typically employing ethanol 47 , 62 , 63 . In this work, both total porosity and size pore distribution were inferred from mercury intrusion porosimetry (MIP, see Experimental Methods section) analysis, to ensure that the whole range of sizes presented by these natural, highly-variable materials, could be included (Fig.…”

“…1 a). Furthermore, in our previous works, it has been reported that morphology, chemical composition, hydrodynamics and mechanical properties of mycelia can be finely tuned by changing both the fungal strain and their growth substrate 45 – 47 .…”

Biological fixed‐film systems

“…In this study, Ahmed, Narayanan, and Veni (2019) evaluated the relationship between Neurospora discreta biofilm and carbon sources. The authors focused on the microstructure, chemical composition, water retention capacity, porosity, and wet weight of the biofilm and carbon sources.…”