基于Plackett–Burma的湖南芥菜发酵菌种高密度培养条件优化

Optimizing the high–density culture conditions for bacteria fermentation of chinese leaf mustard based on Plackett–Burman

为实现湖南芥菜发酵菌种的高密度培养,以感官评分和亚硝酸盐含量为评价指标,从自然发酵湖南芥菜中筛选出合适作芥菜发酵剂的LA与R6组合混合菌种和R2单一菌种。采用Plackett–Burma从11种营养物质中筛选出葡萄糖、硫酸铵、胰蛋白胨、牛肉膏为LA与R6混合菌种的主要增殖物质;乳清粉、硫酸铵、胰蛋白胨、酵母浸出粉为R2菌种的主要增殖物质。通过布列可特—博曼(Plackett–Burma)设计方法和正交试验,得出LA与R6混合菌种培养基最优配方是葡萄糖3%、牛肉膏1.5%、硫酸铵0.5%、胰蛋白胨1%,pH 6.0,在此优化条件下,以3%的接种量,于33℃培养发酵21 h,菌落总数达3.62×10^(10) cfu/mL。R2菌种最优培养基配方为乳清粉4%,硫酸铵1.5%,胰蛋白胨0.5%,酵母浸出粉2%,pH 6.0,在此优化培养条件下,以3%接种量于29℃培养发酵21 h,菌落总数达1.85×10^(12) cfu/mL。

In order to obtain high–density cultivation condition for the fermentation of Hunan brassica juncea,mixed strains of LA and R6,and single strain R2which were suitable for the mustard starter culture,were screened out in the natural fermentation process based on indicators of sensory evaluation and nitrite content.11kinds of nutrients including glucose,ammonium sulfate,tryptone and beef extract were screened out as the main proliferation substances for mixed strains of LA and R6according the result of Plackett–Burma design method;while whey powder,ammonium sulfate,tryptone and yeast extract powder were screened out for those of strain R2.The results showed that the optimum formula for mixed culture medium of LA and R6was consisted of3%glucose,1.5%beef extract,0.5%ammonium sulfate,and1%tryptone in pH6.0.The total number of colonies could reach to3.62×1010cfu/mL in the formula with conditions of3%inoculation,33℃culture temperature,and21h fermentation.For strain R2,the optimum culture medium was consisted of4%whey powder,1.5%ammonium sulfate,0.5%tryptone,and2%yeast extract in pH6.0.The total number of colonies in the formula could reach to1.85×1012cfu/mL at the temperature of29℃for21h of fermentation.