Advances in Streptococcus Research: New Insights into Enzyme Production and Biocompatibility

Strategic Insights -

A team of researchers from the Korea Research Institute of Bioscience and Biotechnology (KRIBB) has made a groundbreaking discovery in the field of Streptococcus research. The scientists have isolated a fructosyltransferase (FTF) gene from Streptococcus salivarius SY511, a strain commonly regarded as safe, and have successfully expressed and purified a recombinant enzyme using nickel affinity chromatography. The enzyme, levansucrase, has been found to catalyze the synthesis of levan, a beta-(2 - 6)-linked fructan with antioxidant, prebiotic, and film-forming properties.

Key Takeaways:

  • The researchers isolated the FTF gene from Streptococcus salivarius SY511 and induced heterologous expression in Escherichia coli.
  • The recombinant enzyme, levansucrase, was purified using nickel affinity chromatography and was found to have an optimal transfructosylation activity at pH 6.0 and 37 degrees C.
  • The enzyme's activity was significantly affected by the presence of metal ions, with Ca2+ and Cu2+ depressing and enhancing activity, respectively.
  • The enzyme retained over 60% of its activity after 4 hours of incubation at 30 degrees C, but activity decreased significantly at higher temperatures.
  • The maximum production of polysaccharide was achieved by incubating 18 U levansucrase/g sucrose with 300 mg/L sucrose for 10 hours.
  • Structural analysis using 13C NMR confirmed the beta-(2 - 6) bonds of levan, and the synthesized levan showed excellent biocompatibility with anti-inflammatory and cytotoxic effects in RAW 264.7 macrophages.
  • The study concluded that the recombinant FTF is a levansucrase that can be produced scalably for functional levan synthesis.

Statistics:

  • The molecular weight of the enzyme was approximately 150 kDa.
  • The enzyme's optimal transfructosylation activity was at pH 6.0 and 37 degrees C.
  • The enzyme retained over 60% of its activity after 4 hours of incubation at 30 degrees C.
  • The maximum production of polysaccharide was achieved by incubating 18 U levansucrase/g sucrose with 300 mg/L sucrose for 10 hours.
  • The synthesized levan showed excellent biocompatibility with anti-inflammatory and cytotoxic effects in RAW 264.7 macrophages.

Sources:

  • Production and Anti-inflammatory Evaluation of B-(2 - 6)-linked Levan Synthesized By a Recombinant Levansucrase From streptococcus Salivarius Sy511. Biotechnology and Bioprocess Engineering, 2025.
  • Korean Soc Biotechnology & Bioengineering, Korean Science Technology Center, #704 Yeogsam-Dong, Kangnam-Ku, Seoul 135-703, South Korea. (Springer - www.springer.com; Biotechnology and Bioprocess Engineering - www.springerlink.com/content/1226-8372/)
  • Baek-Rock Oh, Korea Research Institute of Bioscience and Biotechnology, Microbial Biotechnol Res Ctr, Jeonbuk Branch Institute, Jeongeup 56212, South Korea.
  • Jung-Hyun Ju, Sun-Yeon Heo, and Hee-Ju Kim, co-authors of the research paper.