The miracle filter cloth Miracloth is actually one of the many classic products from Calbiochem, a polyester rayon filter cloth with a pore size of 22-25 μm, which can be used for separating protoplasts, cell homogenate filtration, nucleic acid purification and so on, as well as for a number of other interesting purposes. Genetic engineering transformation of fungi and some soil bacteria, often need to be digested off the thick cell wall, preparation and separation of protoplasts in order to be transformed, even if we are very familiar with the transformation of yeast, when the simple method of lithium acetate does not work, the most primitive and the most effective method is still the transformation of protoplasts. When the digested bacterial mixture is filtered through a Miracloth, the undigested bacteria and impurities are removed, and the isolated "bare" protoplasts are ready for transformation or electrotransformation. Without this step, the rapid growth of incompletely digested organisms can seriously interfere with the results.