IJASEIT

International Journal on Advanced Science, Engineering and Information Technology, Vol. 10 (2020) No. 3, pages: 1207-1213, DOI:10.18517/ijaseit.10.3.5492

Screening for Optimal Parameters of Nattokinase Synthesis by Bacillus subtilis natto in Solid-State Fermentation

Cuong Viet Bui, Minh Nguyet Thi Nguyen, Minh Hanh Thi Truong, Xuan Dong Bui

Abstract

Nattokinase, which is an extracellular enzyme synthesized by Bacillus subtilis natto, is a medication for cardiovascular disease treatment. In this study, soybean seed was used as a substrate for culturing Bacillus subtilis natto in solid-state fermentation to produce nattokinase. The optimal culture parameters for solid-state fermentation to synthesize nattokinase by Bacillus subtilis natto were 2:50 (v:w) of the ratio of Bacillus subtilis natto pre-culture to the substrate, 42 h of fermentation time, and 3 cm of the thickness of the substrate. At this optimal culture parameter of solid-state fermentation by using Bacillus subtilis natto, the enzymatic activity of crude nattokinase was 7.13 ± 0.2, 16.24 ± 0.33, and 16.55 ± 0.06 (specific activity/mL), respectively. Furthermore, we aim to apply this study with large scale production initially. Thus, the ratio of reusing Bacillus subtilis natto in fermentation product to substrate for a new process of solid-state fermentation and circulation time of reusing Bacillus subtilis natto in new solid fermentation process were screened. The maximal enzymatic activity of crude nattokinase of 14.10 ± 0.18 (specific activity/mL) was found at 3:100 (w:w) of reusing Bacillus subtilis natto in fermentation product to substrate for a new process of solid-state fermentation. The suggestion for the circulation time of reusing Bacillus subtilis natto for new solid fermentation process was 2^nd. The results of this study had provided the necessary information for further research on nattokinase.