Relations between substrate morphological change and oxygen transfer in solid-state fermentation ( SSF) using Penicillium decumbens JUA10.

Wang, Lan; Liu, Zhihua; Duan, Yingyi; Chen, Hongzhang

BACKGROUND Substrate morphological change caused by microbial growth should affect oxygen transfer and hence solid-state fermentation ( SSF) performance. Relationships between substrate morphological change caused by fungi growth and oxygen transfer in solid-state substrate were investigated based on porous media theory using fractal dimensions. RESULTS The fungi biomass and oxygen diffusion rate in solid state fermentation followed the order 85% > 75% > 65% for moisture content experiments and 0.4 cm > 1.5 cm > 4.0 cm for particle length experiments, respectively, while permeability showed the opposite trends. Oxygen diffusion rate and permeability decreased as fermentation time was varied from 12 h to 48 h, and then increased with fermentation progress, which was consistent with the fractal dimension. Results indicated that fungi biomass, oxygen diffusion rate, and substrate permeability can be effectively expressed by a fractal dimension. CONCLUSION Combining the kinetic model of permeability and fractal-oxygen exponential model analysis, oxygen transfer was closely related with substrate morphological change expressed by fractal dimension in solid-state fermentation of steam exploded rice straw using Penicillium decumbens JUA10. Thus, oxygen transfer expressed by a fractal dimension should be a more convenient way in solid-state fermentation. © 2014 The Authors. Journal of Chemical Technology & Biotechnology published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

SOLID-state fermentation; BIOCHEMICAL substrates; FRACTAL dimensions; KINETIC theory of gases; DIFFUSION

Journal of Chemical Technology & Biotechnology, 2014, Vol 89, Issue 10, p1582

0268-2575

Academic Journal

10.1002/jctb.4334