title: Oxygen transfer in solid-state cultivation under controlled moisture conditions.
abstract: The aim of this work was to study oxygen transfer as a function of the initial moisture content in solid-state cultivation under controlled moisture conditions. The use of controlled moisture conditions prevents drastic changes in the medium during cultivation, allowing the use of a pseudo-steady-state model to estimate the overall oxygen mass transfer coefficient (K L a) in the biofilm around the solid particles. Drechslera (Helminthosporium) monoceras, an aerobic mold that produces allergenic proteins, was cultured on wheat bran in a packed bed column bioreactor. The bed height (30 mm) and air flow rate (0.4 L/min) were selected to implement moisture control. The results show that there is an optimal moisture content (35 %) at which a lower biofilm thickness and packing of the bed improves K L a. However, a higher biomass growth was obtained at 45 % moisture. The different patterns of biomass growth demonstrate the importance of the balance between aerial and film growth in solid-state cultivation. These results contribute to the understanding of oxygen transfer in solid fermentation, optimization of processes, and production of allergen extracts from D. (Helminthosporium) monoceras biomass.
authors.affiliation: Development of Biotechnological Processes Laboratory, School of Chemical Engineering, University of Campinas, Campinas, São Paulo, 13083-852, Brazil.
authors.forename: R G
authors.initials: RG
authors.lastname: Bastos
authors.forename: F L
authors.initials: FL
authors.lastname: Motta
authors.forename: M H A
authors.initials: MH
authors.lastname: Santana
mesh_terms: D019149:Bioreactors; D006375:Helminthosporium / Q000166:cytology; D010100:Oxygen / Q000737:chemistry*; D014908:Triticum / Q000737:chemistry; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D010100:Oxygen