Validation of a model for process development and scale-up of packed-bed solid-state bioreactors

Area of Science:

• Biotechnology
• Biochemical Engineering
• Mycology

Background:

• Solid-state fermentation (SSF) is a key biotechnological process for producing valuable compounds using fungi.
• Accurate modeling of packed-bed reactors is essential for scaling up SSF processes efficiently.
• Previous models require validation and refinement for diverse fungal species and substrates.

Purpose of the Study:

• To validate a packed-bed solid-state fermenter scale-up model using experimental data.
• To investigate the effects of temperature on fungal growth, respiration, and sporulation.
• To incorporate kinetic data into material and energy balances for improved predictive accuracy.

Main Methods:

• Experimental validation of a packed-bed solid-state fermenter model (15 dm(3)) with Coniothyrium minitans and Aspergillus oryzae.
• Determination of temperature effects on C. minitans respiration, growth, and sporulation on hemp.
• Development of a kinetic model for C. minitans and incorporation into reactor material and energy balances.

Main Results:

• The model accurately predicted temperatures and significant water loss due to evaporative cooling.
• Hemp as a substrate allowed adequate temperature control and prevented shrinkage for both fungi.
• Substrate shrinkage and strong hyphal networks in grains led to channeling and inhomogeneous growth for A. oryzae.

Conclusions:

• The validated model provides accurate temperature predictions for packed-bed solid-state fermentation.
• Substrate properties (shrinkage, hyphal network formation) significantly impact fungal growth and process control.
• Future model improvements should include gas-solid heat/water transfer kinetics and dynamic fungal responses.