Lysine production from methanol at 50°C using Bacillus methanolicus: Modeling volume control, lysine concentration, and productivity using a three-phase continuous simulation

Overexpression of Wild-Type Aspartokinase Increases l -Lysine Production in the Thermotolerant Methylotrophic Bacterium Bacillus methanolicus

“…The medium used, UMN1 medium, contained 4.09 g/liter K 2 HPO 4 , 1.30 g/liter NaH 2 PO 4 , 2.11 g/liter (NH 4 ) 2 SO 4 , 0.25 g/liter yeast extract (Difco), 6 mg/liter d-biotin, 0.01 mg/liter vitamin B 12 , 1 mM MgSO 4 , 1 ml/liter concentrated metal solution (23), and 150 mM methanol. Chloramphenicol (5 g/ml) was added when appropriate.…”

“…The gram-positive and thermotolerant methylotroph Bacillus methanolicus has been studied as an alternative producer of L-glutamate and L-lysine using methanol as the raw material (for a review, see reference 5). We have previously demonstrated that wild-type B. methanolicus produces 58 g/liter of L-glutamate (6), while mutants generated by random chemical mutagenesis have been reported to produce up to 37 g/liter of L-lysine (16,23,34). Favorable properties of B. methanolicus, such as a lack of sporulation at high temperatures, utilization of methanol as an energy and carbon source, a high methanol conversion rate, a high theoretical yield of L-lysine, and an optimal growth temperature of 50°C, indicate that this organism may represent a possible future noncarbohydrate substrate alternative for large-scale production of L-lysine (5).…”

Role of the Bacillus methanolicus Citrate Synthase II Gene, citY , in Regulating the Secretion of Glutamate in l -Lysine-Secreting Mutants

“…The dissimilation of carbon from formaldehyde to CO 2 in B. methanolicus, which may function to detoxify accumulating formaldehyde, has recently been confirmed by 13 C nuclear magnetic resonance and isotope ratio mass spectrometry (39). The theoretical yield of secreted amino acids varies depending on the percentage of formaldehyde carbon dissimilated to CO 2 (39), and therefore control of the feeding of methanol to fed-batch cultures is critical (29).Homoserine dehydrogenase mutants (HSD Ϫ ) of B. methanolicus, which are threonine plus methionine auxotrophs, have been shown to secrete substantial quantities of L-lysine when grown at 50°C in fed-batch cultures on methanol as a sole carbon source and supplied with a source of ammonia (18,29,44). B. methanolicus HSD Ϫ strain 13A52-8A66 can secrete over 60 g of L-lysine plus glutamate (glutamate) per liter, with a mass yield of 0.50 to 0.63 g/g.…”

Disruption ofmetFIncreased L-Lysine Production byMethylophilus methylotrophusfrom Methanol

“…6) Lee et al constructed an L-lysine-producing strain from the thermotolerant Gram-positive facultative methylotroph Bacillus methanolicus, which overproduced L-lysine at relative high temperatures. 7) Many attempts have also been made at L-lysine production, but the results have not satisfied industrial needs yet.…”