| In order to improve the release amount of total ferulic acid from the fermented bran and study its bacteriostasis effect,based on the single factor test,Box-Behnken test and response surface analysis were used to optimize the medium formula for the release of total ferulic acid from the bran fermented by Aspergillus niger and Neurospora sitophila,respectively.Then,the mixed fermentation of the above two fungi was carried out,and the total release amounts of ferulic acid were compared between single fungus and mixed fungi fermentation.The total ferulic acid was extracted from unfermented bran,bran fermented by single fungus and mixed fungi with various solvents,and Escherichia coli and Staphylococcus aureus were selected as the test bacterium to detect the bacteriostasis effect of the total ferulic acid extracts.The test results showed that:(1)The optimized process for ferulic acid production from bran fermented by Aspergillus niger was as follows: 14 mL distill(6.42 g/L maltose,2.00 g/L urea and 0.11 g/L potassium dihydrogen phosphate)and 1.0 mL Aspergillus niger seed solution(1.3×10~8 CFU/mL)were added into 10 g bran,and the fermentation time was 96 h at 30?.The release amounts of total ferulic acid in fermented bran reached the highest 2.72±0.09 mg/g,which was 2.5 times higher than that in the bran without the addition of maltose,urea and potassium dihydrogen phosphate.(2)The optimized process for ferulic acid production from bran fermented by Neurospora sitophila bran was as below: 14 mL distill(7.00 g/L glucose,2.01 g/L urea and 0.11 g/L magnesium chloride)and 1.0 mL Neurospora sitophila seed solution(1.6×10~6 CFU/mL)were added into 10 g bran,and the fermentation time was 60 h at 30?.The release amounts of total ferulic acid in fermented bran reached the highest 1.19±0.02 mg/g,which was 2.7times higher than that in the bran without the addition of glucose,urea and magnesium chloride.(3)The fermentation process of ferulic acid from bran fermented by Aspergillus niger and Neurospora sitophila was as follows: 14 mL distill(6.42 g/L maltose,2.00 g/L urea and 0.11 g/L potassium dihydrogen phosphate)were added into 10 g bran.First,Aspergillus niger was inoculated,the inoculation amount was0.6 mL,and the fermentation time was 24 h at 30?.Then,Neurospora sitophila was inoculated,the inoculation amount was 0.4 mL,and the fermentation time was 72 h at 30?.The release amount of total ferulic acid in fermented bran reached the highest 3.48±0.05 mg/g,which was 28% higher than that of bran fermented of optimized process by Aspergillus niger,and 192% higher than that of bran fermented of optimized process by Neurospora sitophila.(4)Total ferulic acid were extracted from the bran by 45? hot water,80% methanol,ethyl acetate,ethyl acetate:ethanol(1:1),ethyl acetate:ether(1:1),75% ethanol,80%ethanol,85% ethanol,90% ethanol and 95% ethanol,respectively.The results showed that the amount of total ferulic acid in the bran of unfermented,Aspergillus niger,Neurospora sitophila and mixed fungi fermentation extracted with 75% ethanol was the largest,which were 0.12±0.01 mg/g,2.92±0.07 mg/g,1.32±0.22 mg/g and 3.92±0.14 mg/g,respectively.The total ferulic acid extracts were adjusted to equal concentration(10 mg/L),and then bacteriostasis test was carried out.The results showed that total ferulic acid in the unfermented bran extracted with 75% ethanol and 45? hot water had the strongest bacteriostasis on E.coli and S.aureus,and the diameter of bacteriostatic zone was 6.92±0.05 mm and6.38±0.11 mm.The total ferulic acid in the bran fermented by Aspergillus niger extracted with 80%ethanol and 75% ethanol had the strongest bacteriostasis on E.coli and S.aureus,and the diameter of bacteriostatic zone was 9.13±0.10 mm and 9.34±0.09 mm.The total ferulic acid in the bran fermented by Neurospora sitophila extracted with Ethyl acetate and 75% ethanol had the strongest bacteriostasis on E.coli and S.aureus,and the diameter of bacteriostatic zone was 9.82±0.43 mm and 9.07±0.05 mm.The total ferulic acid in the bran fermented by mixed fungi extracted with 75% ethanol had the strongest bacteriostasis action on E.coli and S.aureus,and the diameter of bacteriostatic zone was 11.25±0.10 mm and 11.54±0.29 mm.In conclusion,the release of total ferulic acid from bran by Aspergillus niger and Neurospora sitophila double fungi mixed fermentation was significantly higher than that of single fungus fermentation(P<0.05).The bacteriostasis of 75% ethanol extract of ferulic acid at equal concentration and its derivatives produced by double fungi mixed fermentation was significantly higher than that of single fungus fermentation(P<0.05).This study provides a data reference for the research and development of ferulic acid and its derivatives released by fermentated bran as new bacteriostasis drugs,and for the research and development of bran as alternative functional feed. |
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