A method for prevention of microbial growth and microbiologically influenced corrosion (MIC) in equipment used for storage and/or transportation of a biofuel, the method comprising applying boron to inner surfaces of compressors, pumps, valves, pipes and storage tanks used in distributing and storing the biofuel by adding boron to said biofuel in the form of a stable solution of boric acid in a solvent, free from any particles larger than 100 nm,
- wherein said boron is added to give a final concentration of elemental boron in said biofuel in an interval of 1 to 50 ppm, and
- wherein said biofuel is chosen from biogas, an ethanol/gasoline blend, ethanol, a methanol/gasoline blend, methanol, an ethanol/diesel blend, a biodiesel according to EN-590 or ASTM D 6751, a blend of biodiesel and petroleum-based diesel, or mixtures thereof.