Described herein are methods to enhance protein secretion in a host cell. In preferred embodiment, the host cell is a gram-positive microorganism such as a Bacillus. In another preferred embodiment, the host cell is a gram-negative microorganism. Preferably the gram-negative microorganism is an Escherichia coli or a member of the genus Pantoaea. Protein secretion may be enhanced by the overexpression of protein components of the Tat pathway. Alternatively, secretion of foreign proteins can be selectively enhanced by forming a chimeric polypeptide comprising a tat signal sequence and the protein of interest. In a preferred embodiment, the tat signal sequence is selected from phoD or LipA.