Cellulase and xylanase production at pilot scale by solid-state fermentation from coffee husk using specialized consortia: The consistency of the process and the microbial communities involved. (November 2017) - Cerda, Alejandra
Graphical abstract: Highlights: Cellulase and xylanase production by SSF from coffee husk was systematically studied. A specialized inoculum was used to assess the reproducibility of enzyme production. Pilot plant triplicates (50 L) revealed a high reproducibility in process evolution. Gaseous emissions were low, except for volatile organic compounds. A complete microbial characterization of SSF is presented for bacteria and fungi. Abstract: Solid state fermentation is a promising technology however rising concerns related to scale up and reproducibility in a productive process. Coffee husk and a specialized inoculum were used in a 4.5 L and then in 50 L reactors to assess the reproducibility of a cellulase and hemicellulase production system. Fermentations were consistent in terms of cellulase production and microbial communities. The higher temperatures achieved when operating at 50 L generated a shift on the microbial communities and a reduction of nearly 50% on cellulase production at pilot scale. In spite, an overall enzymatic production of 3.1 ± 0.5 FPU g −1 DM and 48 ± 4 U g −1 DM for FPase and Xyl activities was obtained, respectively, with low deviation coefficients of 16 and 19% for FPase and Xyl production. Gaseous emissions assessment revealed an emission factor of 2.6 · 10 −3 kg volatile organic compounds per Mg of coffee husk and negligible NH3, CH4 and N2 O emissions.