a pseudomonas aeruginosa mutant derived by random mutagenesis with n-methyl-n¢-nitro-n-nitrosoguanidine, producing high levels of the rhamnolipid biosurfactants was selected on siegmund-wagner (sw) plates. the mutant designated p. aeruginosa ptcc1637 produces rhamnolipids at concentrations 10 time more than parent strain. nmr analysis and surface tension measurement showed that the biosurfactan...

The Clostridium thermocellum cellobiose phosphorylase (CtCBP) is a large protein consisting of 812 amino acids and has great potential in the production of sugar phosphates, novel glycosides, and biofuels. It is relatively stable at 50 1C, but is rapidly inactivated at 70 1C. To stabilize CtCBP at elevated temperatures, two protein-engineering approaches were applied, i.e. site-directed mutagen...

BACKGROUND Although useful for probing bacterial pathogenesis and physiology, current random mutagenesis systems suffer limitations for studying the toxin-producing bacterium Clostridium perfringens. METHODOLOGY/PRINCIPAL FINDINGS An EZ-Tn5-based random mutagenesis approach was developed for use in C. perfringens. This mutagenesis system identified a new regulatory locus controlling toxin pro...