Medium Composition Suitable for L-Lysine Production by Methylophilus methylotrophus in Fed-Batch Cultivation

ArticleinJournal of Bioscience and Bioengineering 106(6):574-9 · January 2009with12 Reads
DOI: 10.1263/jbb.106.574 · Source: PubMed
Abstract
L-Lysine production was investigated in fed-batch fermentation using L-lysine producer of Methylophilus methylotrophus. By the addition of nutrient composition, containing L-methionine, K(2)HPO(4), NaH(2)PO(4), CuSO(4).5aq, MnSO(4).5aq, ZnSO(4).7aq, FeCl(3), MgSO(4).7aq and CaCl(2).2aq, in the feed medium, cell growth could be maintained through the cultivation, and L-lysine production reached to 7.86 g. In addition, the effect of counter ion for NH(4)(+) (Cl(-), SO(4)(2-), glutamate, succinate and citrate) was examined. The result showed that the cell growth in the medium using Cl(-) and glutamate were improved compared with that using SO(4)(2-), succinate and citrate, and L-lysine production in the medium using Cl(-) and glutamate reached to more than 9.0 g. In this experiment, there was a clear correlation between ionic strength and growth rate in the cultivation. In order to examine the influence of ionic strength on growth rate, the activity of enzymes in central metabolic pathway from methanol to pyruvate were assayed using samples at the log-phase and the stationary phase in fed-batch cultivation using (NH(4))(2)SO(4) and (NH(4))Cl as ammonium source. It was found that the higher ionic strength inhibited methanol oxidation activity, which linked to cell growth. In this report, it was revealed that maintaining a relatively low ionic strength had a positive effect on L-lysine production using L-lysine producer of M. methylotrophus.
    • "In addition , some other species identified in our library (Table 1) probably have the potential to metabolize organic compounds. For example, Ideonella dechloratans contains a gene cluster which includes genes that encode both chlorite dismutase and chlorate reductase, and is considered to be an important bacterium for the removal of oxochlorates from the water (Thorell et al., 2003); Rubrivivax gelatinosus may have the ability to metabolize CO and yield H 2 in either the dark or in the light (Maness et al., 2005); strains of Hydrogenophaga taeniospiralis have been found that can grow on biphenyl, or can co-metabolize polychlorinated biphenyls (PCBs) and degrade this organic pollutant in the water (Lambo and Patel, 2006); Methylotenera mobilis can utilize methane, methanol and methylated amines for its growth (Kalyuzhnaya et al., 2010); Methylophilus methylotrophus has been proven to be a good L-lysine producer (in the metabolic pathway converting methanol to pyruvate), and both Cl À and glutamate could improve its growth and metabolic activity (Ishikawa et al., 2008 ). Another noteworthy species from our survey is Candidatus Accumulibacter Phosphatis; although we identified only one clone of this species, it is a known polyphosphateaccumulating organism (PAO) and can be used to enhance biological phosphorus removal (Lu et al., 2007). "
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