Abstract
A Lysine-producing strain recovered from soil was found to produce large amount of the amino acid. The bacterium identified as Bacillus megaterium SP 14 accumulated a lysine yield of 3.56 mg/ml in a broth culture in 96 h. Fermentation experiments show that 8.0% (w/v) glucose and 4.0% (w/v) ammonium chloride used as sources of carbon and nitrogen, respectively, in a medium/fermenter volume ratio of 25.0%, influenced accumulation of the amino acid. Amino acids other than the aspartate family at 0.01% (w/v) stimulated growth and improved lysine yield. Addition of 0.01 unit/ml penicillin to the fermentation medium, immediately after inoculation, stimulated growth and appreciably enhanced lysine accumulation.
Highlights
L-Lysine is nutritionally essential for humans and animals
The isolates were screened for lysine production on solid medium seeded with Escherichia coli 1099 or 5210, following the method described by Halsall (1975)
Of the tested broth cultures of lysineproducing bacteria, strain SP 14 produced a single minhydrin-positive spot which was detected on a paper chromatogram
Summary
L-Lysine is nutritionally essential for humans and animals. It cannot be synthesized internally but may be added to food and feed materials to improve the protein quality (Stillings et al, 1971). A 10% (v/v) seed culture was used to inoculate 100 ml Erlenmeyer flask containing 20 ml of fermentation medium. After 72 h incubation on a rotary shaker at 160 rpm and 30°C, growth and lysine accumulation were determined from the broth culture.
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