High-density Culture and Potential Aquatic Remediation Activity of Bacillus subtilis H001
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
The increase in scale and degree of intensification of aquaculture has led to several environmental issues, such as eutrophication, excessive nitrite content, and presence of pathogenic microorganisms, in the water bodies used for aquaculture. Introduction of probiotics into such water bodies can help prevent and control these critical issues. Bacillus subtilis strain H001 was selected from among ten screened strains as it showed higher amylase (36.7 U/mL) and protease (35.6 U/mL) activities. The medium components were varied in order to optimize the medium for H001 growth, and the effect was investigated in terms of the logarithm of total colony number [log(TCN)]. Highest log(TCN) values for H001 were obtained for 40 g/L bran-based broth, 15g/L corn-based broth, and 20 g/L soybean meal, at 12.1, 12.1, and 14.0, respectively. The log(TCN) was approximately 15 when the mass ratio of corn-based broth (or bran-based broth) to soybean meal was 2:1. The rate of nitrite degradation by H001 in the simulated water body was 94.5%, 95.0%, 84.1%, 68.6%, 48.5%, and 44.4% when the initial nitrite concentration was 5.0, 10.0, 20.0, 30.0, 40.0, and 50.0 mg/L, respectively. In summary, the TCN of Bacillus subtilis H001 with higher amylase and protease activities increased to 1.6 × 1015 CFU/mL after the medium was optimized. This optimized medium was economical and suitable for high-density culture of H001. Strain H001 is presented as a potential aquatic bioremediation agent for water bodies used in aquaculture.
