title: Improvement of lysine production by analog-sensitive and auxotroph mutants of the acetylene-utilizing bacterium Gordona bronchialis (Rhodococcus bronchialis).
abstract: An acetylene utilizing Gordona (Rhodococcus) bronchialis strain, screened for the production of fine chemicals, was found to be capable of producing small amounts of lysine. Attempts to produce amino-acid analog-resistant and/or sensitive mutants and auxotrophs of this strain with increased lysine production were made following UV-irradiation or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) treatment. The bacterium exhibited surprisingly high resistance levels to the aforementioned mutagens which is attributed to highly effective inborn-repair systems. Natural resistance to high levels of S-(2-aminoethyl)-L-cysteine (AEC) (2%) was observed, in contrast with D, L-aspartic acid hydroxamate (AAH), L-lysine hydroxamate (LHX) and beta-fluoropyruvate (FP). A variety of amino-acid analog-resistant (AAHr, LHXr) or analog-sensitive (FPs) mutants were produced following UV-irradiation or MNNG treatment. Similarly, a large number of auxotrophs (68) of different types were also obtained. From these, one FPs mono-auxotroph and two poly-auxotrophs (with at least one requirement for the aspartic acid family) showed an increased lysine production (approximately 1.8 g/L) comparable (4 g/L) to that found in other bacteria capable of utilizing long-chain hydrocarbons (1).
authors.affiliation: Laboratory of General and Agricultural Microbiology, Department of Agricultural Biology and Biotechnology, Athens, Greece.
authors.forename: A
authors.initials: A
authors.lastname: Kyriacou
authors.forename: C
authors.initials: C
authors.lastname: Balis
authors.forename: M A
authors.initials: MA
authors.lastname: Typas
mesh_terms: D000114:Acetylene / Q000378:metabolism*; D001216:Asparagine / Q000031:analogs & derivatives / Q000494:pharmacology; D003545:Cysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D008239:Lysine / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000494:pharmacology; D009154:Mutation; D011773:Pyruvates / Q000494:pharmacology; D012240:Rhodococcus / Q000378:metabolism*
chemical_list: D011773:Pyruvates; C024848:beta-aspartylhydroxamic acid; C039763:lysine hydroxamate; C000204:S-2-aminoethyl cysteine; D001216:Asparagine; D008239:Lysine; D003545:Cysteine; D000114:Acetylene