title: L-lysine production at 50 degrees C by mutants of a newly isolated and characterized methylotrophic Bacillus sp.
abstract: The amino acid L-lysine was produced from homoserine auxotrophic and S-(2-aminoethyl)-L-cysteine-resistant mutants of a newly isolated gram-positive methylotrophic bacterium, capable of growth on methanol at 60 degrees C. The temperature optimum for growth was between 50 and 53 degrees C. These aerobic, gram-positive, endospore-forming, rod-shaped bacteria required biotin and vitamin B12 for growth. Extracts of the bacteria grown on methanol lacked hydroxypyruvate reductase and contained hexulose 6-phosphate synthase activity. Therefore, these bacteria were considered to be type I methylotrophic bacteria of the genus Bacillus. Fed-batch fermentations resulted in cell densities of 50 g of cell dry weight per liter. Biomass yields on carbon, nitrogen, phosphate, and sulfate were determined. Generation of homoserine auxotrophic and amino acid analog-resistant mutants resulted in L-lysine concentrations of nearly 20 g/liter in fed-batch fermentations.
authors.affiliation: Institute for Advanced Studies in Biological Process Technology, Gortner Laboratories, St. Paul, Minnesota.
authors.forename: F J
authors.initials: FJ
authors.lastname: Schendel
authors.forename: C E
authors.initials: CE
authors.lastname: Bremmon
authors.forename: M C
authors.initials: MC
authors.lastname: Flickinger
authors.forename: M
authors.initials: M
authors.lastname: Guettler
authors.forename: R S
authors.initials: RS
authors.lastname: Hanson
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008239:Lysine / Q000096:biosynthesis*; D000432:Methanol / Q000378:metabolism*; D009154:Mutation; D013171:Spores, Bacterial / Q000254:growth & development; D013696:Temperature
chemical_list: D008239:Lysine; D000432:Methanol