Objective To optimize the fermentation condition of Enterococcus faecium with the capability of high-yield biogenic amine production by response surface design. Methods Based on the previous single factor experiment results, response surface methodology was used to investigate the interaction among 3 factors with different levels, namely culture temperature (10, 15, 20 ℃), initial pH (5.0, 5.5, 6.0), and sodium chloride addition (4.5%, 5.5%, 6.5%), on the production of biogenic amines by Enterococcus faecium. The fermentation condition for controlling the production of tyramine and phenethylamine by Enterococcus faecium were optimized. Results The results showed that the regression equations for the production of tyramine and phenethylamine at 48 h were obtained with R2=0.9866, adjusted R2=0.9693 for tyramine and R2=0.9875, adjusted R2=0.9714 for phenethylamine, the order of affecting the production of casein and phenethylamine was culture temperature>NaCl addition>initial pH.. The optimal fermentation condition to control the tyramine production of Enterococcus faecium was initial pH of 6.0, incubation temperature of 10.9 ℃, and NaCl addition level of 4.5%. The optimal fermentation condition to control the phenylethylamine production was initial pH of 5.34, incubation temperature of 13.8 ℃, NaCl addition level of 5.8%. Conclusion The results provide references for the effective control of the biogenic amine production of Enterococcus faecium growing in fermented food such as fermented meat products.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |