Secretion of the sweet-tasting plant protein thaumatin by Bacillus subtilis

With the α-amylase promoter and ribosome binding site, Bacillis subtilis was used to express the sweet plant protein thaumatin II cDNA fused in the correct reading frame to the α-amylase leader peptide. The r-thaumatin was purified from the medium on a S-Sepharose column and detected with western blots by sheep α-thaumatin antibodies. The r-thaumatin and authentic thaumatin were the same size when reduced by 2-ME and the same size when not reduced.