Production of L-Lysine from starch by Corynebacterium glutamicum displaying alpha-amylase on its cell surface.
We engineered a Corynebacterium glutamicum strain displaying alpha-amylase from Streptococcus bovis 148 (AmyA) on its cell surface to produce amino acids directly from starch. We used PgsA from Bacillus subtilis as an anchor protein, and the N-terminus of alpha-amylase was fused to the PgsA. The genes of the fusion protein were integrated into the homoserine dehydrogenase gene locus on the chromosome by homologous recombination. L-Lysine fermentation was carried out using C. glutamicum displaying AmyA in the growth medium containing 50 g/l soluble starch as the sole carbon source. We performed L-lysine fermentation at various temperatures (30-40 degrees C) and pHs (6.0-7.0), as the optimal temperatures and pHs of AmyA and C. glutamicum differ significantly. The highest L-lysine yield was recorded at 30 degrees C and pH 7.0. The amount of soluble starch was reduced to 18.29 g/l, and 6.04 g/l L-lysine was produced in 24 h. The L-lysine yield obtained using soluble starch as the sole carbon source was higher than that using glucose as the sole carbon source after 24 h when the same amount of substrates was added. The results shown in the current study demonstrate that C. glutamicum displaying alpha-amylase has a potential to directly convert soluble starch to amino acids.
Tateno
Toshihiro
T
Department of Molecular Science and Material Engineering, Graduate School of Science and Technology, Kobe University, Kobe 657-8501, Japan.
Fukuda
Hideki
H
Kondo
Akihiko
A
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000201:enzymology* / Q000235:genetics; D005110:Extracellular Space / Q000201:enzymology; D005434:Flow Cytometry; D015971:Gene Expression Regulation, Enzymologic; D005818:Genetic Engineering / Q000379:methods; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D011401:Promoter Regions, Genetic; D013213:Starch / Q000378:metabolism*; D016985:Streptococcus bovis / Q000201:enzymology / Q000235:genetics; D013696:Temperature; D013997:Time Factors; D000516:alpha-Amylases / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D013213:Starch; D000516:alpha-Amylases; D008239:Lysine