Effects were assessed for the post-culture liquid medium originating from the cultivation of microorganisms that are present in the ecosystem called symbiotic consortium bacteria and yeast (SCOBY). The effectiveness of protecting Scotch pine wood samples against decomposition caused by the fungus Coniophora puteana was evaluated. The obtained results confirmed that impregnation of wood with post-culture medium reduces the possibility of decomposition of this wood by the test fungus. The potential biocidal effect of the post-culture medium from SCOBY was attributed to the presence the substances of a potential fungicidal nature, which were synthesized in the culture medium during metabolic processes occurring in the culture. The obtained results encourage further studies on the potential use of metabolites obtained from SCOBY breeding to protect wood against biodegradation.