Residual brewer's yeast biomass and bacterial cellulose as an alternative to toxic phenol-formaldehyde binders in production of pressed materials from waste wood.

Pressed composites can be produced from wood sawdust waste using modified yeast biomass, waste as a bio-adhesive, ultra-dispersed bacterial cellulose (UBC) as a binder, and preliminary chemical cross-linking. The materials obtained were not inferior to traditional materials based on the required levels of toxic phenol-formaldehyde resin and physical and mechanical parameters. Physical and mechanical properties of the materials depended on the amount and viscosity of the binder, as well as on the chemical structure and conditions of chemical cross-linking and modified UBC application. The strengths of the best examples of the materials obtained were approximately 17 to 20 MPa, the densities were in the range of 1207 to 1255 kg/m3, and the water absorption was less than 20%. During hot pressing, notable changes were observed in the wood particles at FTIR-ATR spectra frequencies of 3620 cm -1, 3600 to 3000 cm -1, 2920 cm -1, 2850 cm-1, 1770 cm-1, 1650 cm-1, 1560 cm-1, and 1089 cm-1. This is mainly due to the chemical and structural changes in lignin, hemicellulose, and binder.