Methods for simultaneously synthesizing a biological flocculant with two different components by using
The present application provides a method for simultaneously synthesizing a biological flocculant with polysaccharide and γ-PGA as the active components by using Bacillus licheniformis. Bacillus licheniformis is inoculated to a slant culture medium to be cultured; a single colony on a fresh plate is inoculated to a seed culture medium to be cultured; and a seed fermentation broth is inoculated to a fermentation culture medium to be cultured, and then the biological flocculant having two different components is obtained. The flocculant synthesized in the present invention is high in activity and good in thermal stability; and especially, the flocculation effect of polysaccharide is relatively superior under acidic and neutral conditions, and the flocculation activity of γ-PGA is relatively higher under neutral and alkaline environments, which can satisfy a relatively large pH application range.
1. A method for simultaneously synthesizing a flocculant by using Bacillus licheniformis , wherein the specific steps thereof are as follows:
1) bacterial strain activation: Bacillus licheniformis is inoculated to a slant medium to be cultured, wherein the composition of the slant culture medium is: yeast extract 2 g/L, beef extract 2 g/L, tryptone 5 g/L, glucose 15 g/L, FeSO 4 trace, agar 18 g/L and pH 5˜7.5;
2) preparation of seed: a single colony on a fresh plate is inoculated to a seed culture medium to be cultured, wherein the composition of the seed culture medium is: glucose 10 g/L, yeast extract 0.5 g/L, urea 0.5 g/L, K 2 HPO 4 0.1 g/L, KH 2 PO 4 0.1 g/L, NaCl 0.1 g/L and MgSO 4 ·7H 2 O 0.2 g/L, and;
3) fermentation culture: a seed fermentation broth is inoculated to a fermentation culture medium to be cultured, and then the biological flocculant with two different components is obtained, wherein the composition of the fermentation culture medium is: glucose 5˜15 g/L, trisodium citrate 10˜15 g/L, glycerol 10˜15 g/L, urea 1˜3 g/L, yeast extract 0.5˜1 g/L, NH 4 Cl 2˜6 g/L, sodium glutamate 2˜6 g/L, MgSO 4 0.3˜0.5 g/L, K 2 HPO 4 0.5˜2 g/L, KH 2 PO 4 1˜5 g/L, NaCl 1˜3 g/L and pH 5˜7.5; and
wherein the flocculant prepared by the method has polysaccharide and poly-γ-glutamic acid as two different active components and wherein the polysaccharide content is 26.67%-43.33% and the poly-γ-glutamic acid content is 31.63%.
2. The method for simultaneously synthesizing a flocculant by using Bacillus licheniformis of claim 1 , wherein, in step 1), the culture condition is cultured at 37° C. and 200 r/min for 12˜18 h.
3. The method for simultaneously synthesizing a flocculant by using Bacillus licheniformis of claim 1 , wherein, in step 2), the culture condition is: temperature 37° C., the shaking speed of shaker 200 r/min, and culture time 16 h.
4. The method for simultaneously synthesizing a flocculant by using Bacillus licheniformis of claim 1 , wherein, in step 3), the inoculation amount of the inoculation is 3%.
5. The method for simultaneously synthesizing a flocculant by using Bacillus licheniformis of claim 1 , wherein, in step 3), the culture condition is cultured in shaking flask under the condition of 200 r/min at the temperature of 37° C., with liquid loading volume of 50 mL/250 mL, and fermentation time of 1648 h.