Wood Soap Molds Mold/mildew In Wood?

Mold/mildew in wood? - wood soap molds

How can I get rid of brown to our walls and the roof of the Cathedral of the form of Penicillium? We need to wash with bleach and Murphy Oil Soap, every year, and he feels back to the wood finish. Does anyone have any experience with this that can help?
Thank you very much!