Article

A model for cellulase production from Trichoderma reesei in an airlift reactor.

Laboratoire de modélisation numérique OPPUS, Département de génie chimique et de génie biotechnologique, Université de Sherbrooke, Sherbrooke, Québec, Canada J1K2R1.
Biotechnology and Bioengineering (Impact Factor: 4.16). 08/2012; 109(8):2025-38. DOI: 10.1002/bit.24473
Source: PubMed

ABSTRACT A mathematical model for cellulase production by Trichoderma reesei RUT-C30 grown in a cellulose medium with lactose as fed batch in an airlift reactor is proposed. To describe adequately the mass transfer between the air bubbles and the broth, it uses computational fluid dynamics (CFD) including multiphase Eulerian-Eulerian formulation, with a detailed description of the bubble size distribution through the use of the population balance model (PBM) and the class method (CM). The kinetics of the biomass growth is further coupled to the fluid flow conditions using partial differential equations for all the species involved, providing detailed information of important reactor conditions such as the distribution of oxygen, cellulose, and the shear stress within the reactor over the entire period of fermentation. Predicted results agree well with the available overall measurements for a typical fed-batch operation and detailed profiles of the predicted concentration fields are discussed from an engineering viewpoint.

0 Bookmarks
 · 
157 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present biomassGasificationFoam solver and libraries, developed in an open-source C++ code OpenFOAM (Open Field Operation and Manipulation), for the comprehensive simulation of the physical and thermochemical processes of biomass gasification and pyrolysis. The code biomassGasificationFoam integrates models of drying, pyrolysis, gasification, combustion, and complex flow within a porous biomass. The most important newly implemented functionalities are transient flow in porous media (with changing porosity), a flexible definition of biomass and its properties, heat and mass transfer between gases and solids (with a submodel for heat transfer in wood biomass and radiation heating), homogeneous and het-erogeneous reactions (the heat of reaction is defined directly or based on enthalpies of formations), and customisable kinetic mechanisms of pyrolysis and gasification. The number of subprocesses and possible paths of chemical re-actions involved in the thermal conversion of biomass make the flexibility of the developed code the key factor for successful numerical modelling.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present biomassGasificationFoam solver and libraries, developed in an open-source C++ code OpenFOAM (Open Field Operation and Manipulation), for the comprehensive simulation of the physical and thermochemical processes of biomass gasification and pyrolysis. The code biomassGasificationFoam integrates models of drying, pyrolysis, gasification, combustion, and complex flow within a porous biomass. The most important newly implemented functionalities are transient flow in porous media (with changing porosity), a flexible definition of biomass and its properties, heat and mass transfer between gases and solids (with a submodel for heat transfer in wood biomass and radiation heating), homogeneous and het-erogeneous reactions (the heat of reaction is defined directly or based on enthalpies of formations), and customisable kinetic mechanisms of pyrolysis and gasification. The number of subprocesses and possible paths of chemical re-actions involved in the thermal conversion of biomass make the flexibility of the developed code the key factor for successful numerical modelling.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Penicillin is one of the best known pharmaceuticals and is also an important member of the β-lactam antibiotics. Over the years, ambitious yields, titers, productivities, and low costs in the production of the β-lactam antibiotics have been stepwise realized through successive rounds of strain improvement and process optimization. Penicillium chrysogenum was proven to be an ideal cell factory for the production of penicillin, and successful approaches were exploited to elevate the production titer. However, the industrial production of penicillin faces the serious challenge that environmental gradients, which are caused by insufficient mixing and mass transfer limitations, exert a considerably negative impact on the ultimate productivity and yield. Scale-down studies regarding diverse environmental gradients have been carried out on bacteria, yeasts, and filamentous fungi as well as animal cells. In accordance, a variety of scale-down devices combined with fast sampling and quenching protocols have been established to acquire the true snapshots of the perturbed cellular conditions. The perturbed metabolome information stemming from scale-down studies contributed to the comprehension of the production process and the identification of improvement approaches. However, little is known about the influence of the flow field and the mechanisms of intracellular metabolism. Consequently, it is still rather difficult to realize a fully rational scale-up. In the future, developing a computer framework to simulate the flow field of the large-scale fermenters is highly recommended. Furthermore, a metabolically structured kinetic model directly related to the production of penicillin will be further coupled to the fluid flow dynamics. A mathematical model including the information from both computational fluid dynamics and chemical reaction dynamics will then be established for the prediction of detailed information over the entire period of the fermentation process and thereby for the optimization of penicillin production, and subsequently also benefiting other fermentation products.
    Applied Microbiology and Biotechnology 01/2014; · 3.69 Impact Factor