Enzymatic synthesis of amylose nanocomposite microbeads using amylosucrase from Deinococcus geothermalis

Abstract

This communication reports a biological approach to synthesize pure amylose microbeads and amylose–SWCNT composite microbeads using the amylosucrase from Deinococcus geothermalis.

Effect of short-chain fatty acids on the formation of amylose microparticles by amylosucrase

“…The intensities of the peaks were not affected by the presence of fatty acids in the reaction mixture indicating no change in the degree of crystallinity. On the other hand, the crystallinity of amylose microparticles synthesized together with carbon nanotubes and iron oxide nanoparticles has been shown to be notably decreased compared with that of controls (Lim et al, 2015(Lim et al, , 2014. These results taken together indicate that the presence of fatty acids in the synthesis disturbed neither the self-assembly of amylose nor the crystal structure.…”

“…Through the enzymatic polymerization cycle, malto-oligosaccharides and longer amylose chains were produced and the amylose chains used hydrophobic interactions and hydrogen bonding to self-associate. Hydrophobic guest molecules such as carbon nanotubes and iron oxide nanoparticles can be easily complexed with the synthesized amylose chains to form amylose composite microparticles through the above enzymatic reaction (Lim et al, 2015(Lim et al, , 2014.…”

“…Escherichia coli MC1061 was used as the host microorganism for the expression vector pHCDGAS, encoding recombinant amylosucrase from Deinococcus geothermalis (DGAS). DGAS was prepared as described earlier (Lim et al, 2014). Briefly, recombinant E. coli MC1061 harboring pHCDGAS was grown in 500 mL LB broth (0.1 mg/mL ampicillin) at 37 • C for 24 h at 250 rpm.…”

“…The elongation of maltose to the longer amylose is achieved via a repeated polymerization cycle. Recently, an amylosucrase-mediated production of an amylose nanocomposite embedding carbon nanotubes and iron oxide nanoparticles as guest molecules was reported (Lim et al, 2015(Lim et al, , 2014. Phosphorylase has also been reported to produce an amylose-fatty acid complex using maltohexaose and Glc-1-P as substrates and fatty acids with chain lengths greater than C14 as guest molecules (Gelders, Goesaert, & Delcour, 2005).…”

Amylosucrase‐mediated β‐carotene encapsulation in amylose microparticles

“…However, the requirement of expensive substrate, G‐1‐P, as well as the needs of additional component, maltooligosaccharides, as a glycosyl acceptor limit its applications to larger scale production. Recently, we reported amylose produced from the enzymatic reaction of DgAS self‐assembles into spherical microstructures, and various guest compounds can be incorporated spontaneously into the microparticles during the self‐assembly process . In this study, we employed the unique catalytic characteristics of DgAS to encapsulate BC into well‐defined amylose microparticles (AmMPs) to enhance the stability of BC against common environmental stresses, such as UV light and oxidants.…”