High Cell Density Cultivation of A Recombinant Bacillus Subtilis for Nattokinase Production release_q2hgytkjgna5pbbhlsau52hjzq

by Jianhua Zhang, Qing Cui, Bingjun Qian, Xiangjun Sun

Released as a post by Research Square.

2020  

Abstract

<jats:title>Abstract</jats:title> <jats:bold>Background:</jats:bold> Nattokinase (NK), a fibrinolytic enzyme, can be produced by culturing<jats:italic> </jats:italic>recombinant<jats:italic> Bacillus subtilis</jats:italic> in Luria-Bertani broth<jats:italic> </jats:italic>in a shaking flask. For use as a nutraceutical, however, a large-scale preparation and a simple purification process are required.<jats:bold>Results</jats:bold>: The present study utilized a fed-batch process to cultivate a<jats:italic> B.</jats:italic> <jats:italic>subtilis </jats:italic>strain<jats:italic> </jats:italic>carrying a pHT01 plasmid with an NK-encoding gene (<jats:italic>B. subtilis</jats:italic>/pHT01-<jats:italic>apr</jats:italic>N1). For batch A (FB A), with a pH-stat two-stage fermentation strategy, we achieved an activity of 2910.5 ± 21.6 U mL<jats:sup>-1</jats:sup> and a specific activity of 30.32 U ml<jats:sup>-1</jats:sup> OD<jats:sub>600</jats:sub><jats:sup>-1</jats:sup>. Then, we changed the strategy with a later induction and lower feeding rate to pursue higher cell density and thus higher enzyme activity, a 11.9-fold activity of 4521.8 ± 23.8 U mL<jats:sup>-1</jats:sup> was acquired, however, the specific activity was lower than FB A. For the third batch, low-glycerol-level-maintain feeding strategy was followed, and finally, a NK activity of 7778 ±17.28 U mL<jats:sup>-1</jats:sup> was obtained, according to our knowledge, it was the highest activity assayed by the fibrin plate method ever reported. Furthermore, fermentation supernatant was successively purified by ammonium sulfate precipitation and nickel column affinity chromatography with a total NK recovery rate of 65.2%.<jats:bold>Conclusions: </jats:bold>Our results indicate that there is a balance between the cell growth rate and NK expression when recombinant<jats:italic> Bacillus subtilis</jats:italic> is cultured with a fed-batch process. The equilibrium state can be attained by optimizing the induction and feeding strategy, and thus a high cell density and enzyme activity can be achieved.
In application/xml+jats format

Archived Files and Locations

application/pdf  272.0 kB
file_f2eccxbnsrchxho5wbvq7jcas4
assets.researchsquare.com (publisher)
web.archive.org (webarchive)
Read Archived PDF
Preserved and Accessible
Type  post
Stage   unknown
Date   2020-10-16
Work Entity
access all versions, variants, and formats of this works (eg, pre-prints)
Catalog Record
Revision: 2368386d-e251-4f4d-87d8-7cddfee840da
API URL: JSON