Biosynthesis of poly(epsilon-L-lysine)s in two newly isolated strains of Streptomyces sp.
The biosynthesis of poly(epsilon-L-lysine) (epsilon-PL) in the two newly isolated strains of Streptomyces lydicus USE-11 (USE-11) and Streptomyces sp. USE-51 (USE-51) was studied by a newly developed two-stage culture method of cell growth at pH 6.8 and epsilon-PL production at pH 4.5. USE-11 synthesized epsilon-PL consisting of about 28 residues at a high production level, whereas USE-51 did the polymer with 15 ones at a low level. The secreted epsilon-PLs in culture media were digested in a neutral pH range with a peptide hydrolase(s) produced by the epsilon-PL producers. The optimum production levels were presumed to be dependent upon the inherent epsilon-PL synthesis machinery of each producer. The production in USE-51 was sharply dependent upon cell density as was often observed in the production of antibiotics, whereas that in USE-11 was scarcely affected by the density. The SO(4)(2-) was found to be essential for the epsilon-PL production in both strains. This might suggest the involvement of a thiol group in the polymerization reactions including the activation of L-lysine. This study indicates that USE-11 is a most suitable strain for the exploration of the epsilon-PL biosynthesis at the molecular level as well as for the technical applications.
Hirohara
Hideo
H
Department of Materials Science, University of Shiga Prefecture, Hassaka, Hikone 522-8533, Japan. hirohara@mat.usp.ac.jp
Takehara
Munenori
M
Saimura
Masayuki
M
Ikezaki
Atsushi
A
Masayuki
Atsushi
A
Miyamoto
Masahiro
M
D001709:Biotechnology / Q000379:methods*; D002412:Cations; D002625:Chemistry, Organic / Q000379:methods; D005990:Glycerol / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008968:Molecular Conformation; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D011107:Polylysine / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D013302:Streptomyces / Q000378:metabolism*
D002412:Cations; D010455:Peptides; D011108:Polymers; D011107:Polylysine; D008239:Lysine; D009584:Nitrogen; D005990:Glycerol