本文从豆豉中分离出了一株高产MK-7的菌株并对其进行了鉴定,同时对该菌合成MK-7的条件进行了初步研究。在参照《伯杰氏细菌鉴定手册》,并根据形态学特征、生理生化特性、并结合16S rDNA序列分析结果,该菌属于解淀粉芽孢杆菌。该菌合成M...本文从豆豉中分离出了一株高产MK-7的菌株并对其进行了鉴定,同时对该菌合成MK-7的条件进行了初步研究。在参照《伯杰氏细菌鉴定手册》,并根据形态学特征、生理生化特性、并结合16S rDNA序列分析结果,该菌属于解淀粉芽孢杆菌。该菌合成MK-7的最佳条件为:发酵温度37℃、装液量为30 m L/250 m L、接种量为2%和摇瓶培养时间为3 h。研究发现,菌株Y-2合成的MK-7主要存在于细胞内。以上结果可为基于菌株Y-2选育高产MK-7菌株和实现MK-7的产业化提供理论依据。展开更多
A menaquinone-7（MK-7） high-producing strain needs to be isolated to increase MK-7 production, in order to meet a requirement of MK-7 given the low MK-7 content in food products. This article focuses on developing MK...A menaquinone-7（MK-7） high-producing strain needs to be isolated to increase MK-7 production, in order to meet a requirement of MK-7 given the low MK-7 content in food products. This article focuses on developing MK-7 high-producing strains via screening and mutagenesis by an atmospheric and room temperature plasma（ARTP） mutation breeding system. We isolated an MK-7-producing strain Y-2 and identified it as Bacillus amyloliquefaciens, which produced（7.1±0.5） mg/L of MK-7 with maize meal hydrolysate as carbon source. Then, an MK-7 highproducing strain B. amyloliquefaciens H.β.D.R.-5 with resistance to 1-hydroxy-2-naphthoic acid, β-2-thienylalanine, and diphenylamine was obtained from the mutation of the strain Y-2 using an ARTP mutation breeding system. Using strain H.β.D.R.-5, efficient production of MK-7 was achieved（（30.2±2.7） mg/L）. In addition, the effects of nitrogen sources, prenyl alcohols, and MgSO_4 on MK-7 production were investigated, suggesting that soymeal extract combined with yeast extract, isopentenol, and MgSO4 was beneficial. Under the optimized condition, the MK-7 production and biomass-specific yield reached（61.3±5.2） mg/L and 2.59 mg/L per OD600 unit respectively in a 7-L fermenter. These results demonstrated that strain H.β.D.R.-5 has the capacity to produce MK-7 from maize meal hydrolysate, which could reduce the substrate cost.展开更多
文摘本文从豆豉中分离出了一株高产MK-7的菌株并对其进行了鉴定,同时对该菌合成MK-7的条件进行了初步研究。在参照《伯杰氏细菌鉴定手册》,并根据形态学特征、生理生化特性、并结合16S rDNA序列分析结果,该菌属于解淀粉芽孢杆菌。该菌合成MK-7的最佳条件为:发酵温度37℃、装液量为30 m L/250 m L、接种量为2%和摇瓶培养时间为3 h。研究发现,菌株Y-2合成的MK-7主要存在于细胞内。以上结果可为基于菌株Y-2选育高产MK-7菌株和实现MK-7的产业化提供理论依据。
基金supported by the Natural Science Foundation of Jiangsu Province(No.BK20150149),China
文摘A menaquinone-7（MK-7） high-producing strain needs to be isolated to increase MK-7 production, in order to meet a requirement of MK-7 given the low MK-7 content in food products. This article focuses on developing MK-7 high-producing strains via screening and mutagenesis by an atmospheric and room temperature plasma（ARTP） mutation breeding system. We isolated an MK-7-producing strain Y-2 and identified it as Bacillus amyloliquefaciens, which produced（7.1±0.5） mg/L of MK-7 with maize meal hydrolysate as carbon source. Then, an MK-7 highproducing strain B. amyloliquefaciens H.β.D.R.-5 with resistance to 1-hydroxy-2-naphthoic acid, β-2-thienylalanine, and diphenylamine was obtained from the mutation of the strain Y-2 using an ARTP mutation breeding system. Using strain H.β.D.R.-5, efficient production of MK-7 was achieved（（30.2±2.7） mg/L）. In addition, the effects of nitrogen sources, prenyl alcohols, and MgSO_4 on MK-7 production were investigated, suggesting that soymeal extract combined with yeast extract, isopentenol, and MgSO4 was beneficial. Under the optimized condition, the MK-7 production and biomass-specific yield reached（61.3±5.2） mg/L and 2.59 mg/L per OD600 unit respectively in a 7-L fermenter. These results demonstrated that strain H.β.D.R.-5 has the capacity to produce MK-7 from maize meal hydrolysate, which could reduce the substrate cost.
