Abstract: A process for the production of an E. coli strain producing high yields of 7.beta.-(4-carboxybutanamido) cephalosporin acylase, comprises: (a) digesting the DNA of a microorganism whose DNA includes the sequence encoding 7.beta.-(4-carboxybutanamido) cephalosporin acylase, and forming a plasmidic library; (b) transforming, with the sequences in the plasmidic library, an auxotrophic E. coli host; (c) selecting for transformed E. coli hosts containing the acylase sequence by growth on a suitable medium; (d) isolating the vector containing the acylase sequence, digesting the vector, and ligating the DNA sequences obtained into an E. coli vector under control of an E. coli promoter; (e) repeating selection procedure of step (c) ; (f) using the vectors from the selected E. coli hosts to transform an E. coli host lacking substantial .beta.-lactamase activity. 7-Aminocephalosporanic acid and its derivatives can be prepared by reaction of substrates like 7.beta.-(4-carboxybutanamido) cephalosporanic acid with 7.beta.

Abstract: A process for the preparation of alpha-(N-pyrrolyl)-derivative acids, the salts and esters thereof, of the formula ##STR1## in which R, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are hydrogen atoms or substituted or unsubstituted alkyl, aryl, alkylaryl or heterocyclic radicals and R' is a metal cation, an organic base or an organic radical, wherein the corresponding amino ester is reacted with a dialkoxytetrahydrofuran or a derivative thereof. Certain compounds comprised among those corresponding to the above formula, particularly the DL, D and L-alpha-(N-pyrrolyl)-phenylacetic acids and certain esters thereof. Therapeutical compositions containing such compounds as active ingredient and therapeutical applications of said compounds.