It is a rapid method for screening the tyrosine phenol lyase producer according to the size of the red color ring by using methyl phenol red as the indicator in the solid medium containing tyrosine.

• 以甲酚红作指示剂，在加有酪氨酸的固态培养基上，根据甲酚红由黄变红所形成的变色圈的大小筛选酪氨酸酚解酶高产突变株是一种平板快速筛选方法。