摘要
Bacteriophages infected different serotypes of Klebsiella were isolated from sewage. Among them, a heatstable polysaccharide depolymerase enzyme which could degrade bacterial exopolysaccharide effectively was prepared from the phage infecting Klebsiella K13. Treatment at 60℃ for 30 min could inactivate most of the K13 phage, with the titration decreasing from 6.4×10^8 PFU/mL to 1.6×10^6 PFU/mL. However, no obvious loss of phage enzyme activity was found after this treatment. The optimum hydrolytic temperature of phage enzyme was 60℃, with an activity 57 % higher than that at 30℃. The addition of phage enzyme could result in a rapid decrease of viscosity of exopolysaccharide （EPS） solution within minutes, indicating that K13 phage polysaccharide depolymerase acts as a kind of endo-glycanohydrolase. HPLC and reducing sugar analysis showed that the hydrolysis of EPS approached approximately the maxi-mum at 4h when the final concentration of phage was 6.0 x los PFU/mL. The results showed that K/eb-siella K13 phage depolymerase enzyme could be used as a good tool for the preparation of EPS oligosac- charide.
<正> Bacteriophages infected different serotypes of Klebsiella were isolated from sewage.Among them,aheat-stable polysaccharide depolymerase enzyme which could degrade bacterial exopolysaccharide effec-tively was prepared from the phage infecting Klebsiella K13.Treatment at 60℃ for 30 min could inacti-vate most of the K13 phage,with the titration decreasing from 6.4×10~8 PFU/mL to 1.6×10~6 PFU/mL.However,no obvious loss of phage enzyme activity was found after this treatment.The optimum hydrolytictemperature of phage enzyme was 60℃,with an activity 57% higher than that at 30℃.The addition ofphage enzyme could result in a rapid decrease of viscosity of exopolysaccharide(EPS)solution withinminutes,indicating that K13 phage polysaccharide depolymerase acts as a kind of endo-glyeanohydrolase.HPLC and reducing sugar analysis showed that the hydrolysis of EPS approached approximately the maxi-mum at 4h when the final concentration of phage was 6.0×10~8 PFU/mL.The results showed that Kleb-sieUa K13 phage depolymerase enzyme could be used as a good tool for the preparation of EPS oligosac-charide.
基金
the National Natural Science Foundation of China(No40506027 and No30771646)
the Doctoral Foundation of Shandong Province(No2005BS02015)
