Protein Hydrolysates from Non-bovine and Plant Sources Replaces Tryptone in Microbiological Media

Abstract

Tryptone (pancreatic digest of casein) is a common ingredient in laboratory and fermentation media for growing wild-type and genetically modified microorganisms. Many of the commercially manufactured products such as human growth hormone, antibiotics, insulin, etc. are produced by recombinant strains grown on materials derived from bovine sources. With the emergence of Bovine Spongiform Encephalopathy (BSE) and the consequent increase in Food and Drug Administration (FDA) regulations, elimination of materials of bovine origin from fermentation media is of paramount importance. To achieve this objective, a number of protein hydrolysates derived from non-bovine animal and plant sources were evaluated. Tryptone in Luria-Bertani (LB) broth was replaced with an equal quantity of alternate protein hydrolysates. Four of the six hydrolysates (one animal and three from plants) were found to efficiently replace the tryptone present in LB-medium as measured by growth rate and growth yield of a recombinant Escherichia coli strain. In addition, we have determined plasmid stability, inducibility and activity of the plasmid encoded β-galactosidase in the recombinant strain grown in the presence of various protein hydrolysates.