Lysine Production From Methanol

Methylotrophs, microorganisms that use reduced one-carbon compounds, are diverse and ubiquitous. Even though many methylotrophs have been described, only a few are gram positive. The industrial advantages of using methanol as a substrate for large-scale production of fermentation products have been outlined by other groups. Methanol is relatively inexpensive, prices are relatively stable, production exceeds demand, and it is easily stored and transported. In addition, methanol is available in pure form, it is highly soluble in water, methanol solutions are not explosive, and residual methanol can be easily removed from products after fermentation is completed. Bacillus species have been used extensively in industrial fermentation processes, but little information has been published on the isolation of Bacillus species capable of rapid growth on methanol at temperatures above 50 oC.

The nutritionally important amino acid L-lysine is a member of the aspartate family of amino acids and is primarily used in supplements for animal feeds made from grains that contain only limited quantities of L-lysine. Poultry, swine, and other livestock are unable to synthesize L-lysine and therefore must have this amino acid supplied as part of their diet. Currently, L-lysine is being manufactured by either direct fermentation, or enzymatic conversion of DL-a-amino-e-caprolactam. Fermentations that use strains of Corynebacterium glutamicum or Brevibacterium lactofermentum with molasses or starch hydrolysate as feedstocks have become the major method of L-lysine production.

CEBTech has experience with a project involving the isolation, characterization, growth and L-lysine production from, a gram-positive endospore-forming methylotroph that grew rapidly on methanol at 60 oC. The organism discovered was eventually named Bacillus methanolicus. Mutants of this newly discovered methylotroph that were homoserine auxotrophs and S-(2-aminoethyl)-cysteine (AEC) resistant, were found capable of secreting significant amounts of the amino acid L-lysine. Figures 1 - 4 below show much of the run data generated during fermentations using homoserine auxotrophic and amino acid analog-resistant mutants of Bacillus methanolicus.


A 20L Chemap Fermenter
Using a Methylotroph
to Produce Lysine

Fed-Batch Fermentation
of Methanol to Lysine
with Methyotrophic Mutant MGA3

Fed-Batch Fermentation
of NAO2 Under
Phosphate Limitation

Fed-Batch Fermentation
of NAO2 Showing DCW
OUR, CER, Amino Acids

Fed_Batch Process Diagram
Methylotrophic Fermentation
for Animal Feed Production



Continuous Process Diagram
for Animal Feed Production
Methylotrophic Fermentation


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