COPENHAGEN — A Danish biotechnology company is trying to fight climate change — one laundry load at a time. Its secret weapon: mushrooms like those in a dormant forest outside Copenhagen. In the quest for a more environmentally friendly detergent, two scientists at the company, Novozymes, regularly trudge through the mud, hunting for oyster mushrooms that protrude from a fallen beech or bracken fungi that feast on tough plant fibers. …Enlisting enzymes to battle dirt is not a new strategy. Over thousands of years, mushrooms and their fungi cousins have evolved into masters at nourishing themselves on dying trees, fallen branches and other materials. They break down these difficult materials by secreting enzymes into their hosts. Even before anyone knew what enzymes were, they were used in brewing and cheese making, among other activities.