title: Poly(L-diaminopropionic acid), a novel non-proteinic amino acid oligomer co-produced with poly(ε-L-lysine) by Streptomyces albulus PD-1.
abstract: Poly(ε-L-lysine) (ε-PL) producer strain Streptomyces albulus PD-1 secreted a novel polymeric substance into its culture broth along with ε-PL. The polymeric substance was purified to homogeneity and identified. Matrix-assisted laser desorption ionization-time of flight mass spectrometry and nuclear magnetic resonance spectroscopy as well as other analytical techniques revealed that the substance was poly(L-diaminopropionic acid) (PDAP). PDAP is an L-α,β-diaminopropionic acid oligomer linking between amino and carboxylic acid functional groups. The molecular weight of PDAP ranged from 500 to 1500 Da, and no co-polymers composed of L-diaminopropionic acid and L-lysine were present in the culture broth. Compared with ε-PL, PDAP exhibited stronger inhibitory activities against yeasts but weaker activities against bacteria. ε-PL and PDAP co-production was also investigated. Both ε-PL and PDAP were synthesized during the stationary phase of growth, and the final ε-PL and PDAP concentration reached 21.7 and 4.8 g L(-1), respectively, in fed-batch fermentation. Citric acid feeding resulted in a maximum ε-PL concentration of 26.1 g L(-1) and a decrease in the final concentration of PDAP to 3.8 g L(-1). No studies on ε-PL and PDAP co-production in Streptomyces albulus have been reported previously, and inhibition of by-products such as PDAP is potentially useful in ε-PL production.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing University of Technology, No. 30 South Puzhu Road, Pukou District, Nanjing, 211816, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Xia
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Feng
authors.forename: Zhaoxian
authors.initials: Z
authors.lastname: Xu
authors.forename: Bo
authors.initials: B
authors.lastname: Chi
mesh_terms: D005285:Fermentation; D008239:Lysine / Q000096:biosynthesis*; D008970:Molecular Weight; D009757:Nylons / Q000737:chemistry / Q000378:metabolism*; D013302:Streptomyces / Q000254:growth & development / Q000378:metabolism*
chemical_list: D009757:Nylons; D008239:Lysine