Teicoplanin is a glycopeptide antibiotic produced by Actinoplanes teichomyceticus. A strain improvement to increase the productivity of the major component, teicoplanin A(2-2), was carried out. As the fatty moiety of teicoplanin A(2-2) is derived from L-valine, L-valine analogue (valine hydroxamate)-resistant mutants were derived. One of the mutants, 98-1-227, overproduced valine and produced a higher titer of total teicoplanin with higher A(2-2) content. In a pilot fermentor (7 m(3)), the total productivity of teicoplanin was 1,800 units/ml and the A(2-2) content was 58%.