### Mutation breeding of high-yield exopolysaccharide-producing strains by nitrogen ion beam implantation

WAN Honggui  WANG Wenjuan  MIAO Lingling  ZHANG Bo  WANG Wenjin

1. (College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 211816, China)
• Received:2011-09-01 Revised:2011-10-15 Online:2012-06-20 Published:2014-09-11

Abstract:

The spores of strain producing exopolysaccharide were mutated by N+ ions implantation to obtain a high-yield strain of exopolysaccharide in this study. The used energy and dose during the implantation process was about 10 keV and 60×1014–140×1014 cm-2, respectively. The optimal dose was decided by the livability and mutation rate of the strain. It was found that the curve of survival took a “saddle shape” with increasing N+ ion dose. The best induced mutation action was obtained when the ions implantation dose was 120×1014 cm-2. After the selection and 5 generations of propagation, the mutant strain with high stability was obtained, whose exopolysaccharide yield reached 3.29 g/L, which was about 19.20% higher than that of the original strain, and the fermentation time was decreased by 6 h.

CLC Number:

• TQ929+2，Q93