A protein having an L-proline efflux function and the use thereof are provided. A method for producing L-proline or hydroxyproline by means of using a protein ThrE is used for producing L-proline by means of enhancing the activity of a polypeptide, having an L-proline efflux function, in an L-proline-producing strain. Alternatively, the method is used for producing hydroxyproline by means of weakening the activity of a polypeptide, having an L-proline efflux function, in L-proline-producing host cells and enhancing the activity of a proline hydroxylase.

Provided herein are cell-free systems for generating carbapenems, e.g., a compound of the Formula (I):

##STR00001##

or salts thereof; wherein , R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are defined herein. Also provided are pharmaceutical compositions comprising a compound generated by the inventive cell-free system, and use of these compounds and compositions for the treatment of bacterial infections.