The Effects of Different Carbon and Nitrogen Nutrients and Culture Conditions on the Growth of Bacillus sp. Strain A4

Abstract:

In this study, we explored how the nutritional and culture conditions affected the growth of a Bacillus sp. strain A4 and identified the growth characteristics of this strain during the multi-factor interaction. We first applied the single factor test to study the effects of different carbon and nitrogen sources, and then employed Plackett-Burman (PB) test to evaluate the effects of seven factors including carbon source, nitrogen source, pH value, inoculation amount, temperature, rotation speed and liquid volume in the flask. The results showed that the absorption efficiencies of strain A4 for different carbon and nitrogen sources were different. We found that the corn steep liquor was the best carbon source for strain A4, and that the soybean protein was the best nitrogen source. When cultured with the corn steep liquor or the soybean protein for 24 h, the amounts of bacteria reached 3.58×108 CFU/ml and 3.19×108 CFU/ml respectively. The results of Plackett-Burman (PB) test showed that the order of factors affecting the growth of strain A4 as soybean protein> temperature>corn steep liquor>rotation speed>inoculation amount>pH value>liquid volume in the flask. Moreover, the soybean protein as the nutritional factor and the temperature as the culture condition both had significant effects on the growth of strain A4 (P<0.05). Temperature had a greater effect on the growth of strain A4 than the corn liquid factor. The results above indicated that the culture conditions played a vital role in the growth regulation of the bacteria. We also recommend that it should be essential to associate the nutritional factors with the culture conditions when evaluating the effects of related factors on the growth or ecological function of bacteria.