酿酒酵母XM2-9流加发酵生产甲基硒代半胱氨酸  

Se-Methylselenocysteine Production by Saccharomyces cerevisiae XM2-9 Using Fed-Batch Fermentation Mode

作　　者：吴江 洪文荣 苏敏 洪晓明 WU Jiang;HONG Wenrong;SU Min;HONG Xiaoming(AUCH International Trading Pty Ltd,Sydney,NSW2000,Australia;Putian Institute,Putian 351100,China;Chongqing Medicine and Nutrition Centre,Chongqing 402260,China)

机构地区：[1]AUCH International Trading Pty Ltd,Sydney,NSW2000,Australia [2]莆田学院,福建莆田351100 [3]重庆能源学院医药和营养研究中心,重庆402260

出　　处：《食品与生物技术学报》2021年第7期103-111,共9页Journal of Food Science and Biotechnology

基　　金：AUCH International Trading Pty Ltd生物技术创新项目(AI2019029)。

摘　　要：以高产硒酵母Saccharomyces cerevisiae XM2-9为生产菌株,采用双流加发酵工艺生产甲基硒代半胱氨酸(Se-methylselenocysteine)。通过分批发酵优化了培养基,并且计算出在不同的初始亚硒酸钠质量浓度下菌体细胞的比生长速率,同时也分别计算出在不同浓度的硫酸镁培养基下菌体的比硒消耗速率,得到最高比硒消耗速率为0.47 mg/(g·h)。发酵过程采用双流加工艺,即首先以葡萄糖培养基作为补料,以菌体的比生长速率为依据选择了3个流量进行恒速流加试验,同时以比硒消耗速率为依据,控制亚硒酸钠溶液的流加量。实验表明,当葡萄糖培养基流量为0.8 L/h时,得到了最大的有机硒生产强度(organic selenium productivity),其值为10.16 mg/(L·h)。通过对葡萄糖流加的研究发现,指数流加模式比恒速流加模式更佳。结果表明,当以设定的比生长速率μ=0.08 h-1所计算出的流量进行指数流加时,得到了最大的有机硒生产强度,其值为12.55 mg/(L·h)。在此优化条件下,最终的酵母菌体质量浓度达到35.6 g/L,细胞中有机硒质量分数为4937μg/g,其中甲基硒代半胱氨酸中的硒质量占总硒72%,即为3555μg/g。根据相对分子质量换算,甲基硒代半胱氨酸质量分数达到8189μg/g。The mutant of Saccharomyces cerevisiae XM2-9 has been used for the production of Se-methylselenocysteine by fed-batch fermentation.First,the optimal medium and sulfur concentration were obtained by batch fermentation.The specific growth rate of cell at different initial disodium selenite concentrations was calculated.Meanwhile,the specific selenium consumption rate(SSCR)was calculated under different concentrations of magnesium sulfate,and the highest SSCR of 0.47 mg/(g·h)was achieved.Afterward,Se-methylselenocysteine production was carried out using a fed-batch fermentation mode.At first,the glucose medium was used as the feeding material.Then three flow rates were selected to carry out the constant flow test according to the calculation of the specific growth rate of the yeast cell.Simultaneously,the flow rate of disodium selenite solution was controlled via SSCR.The highest organic selenium productivity of 10.16 mg/(L·h)was achieved when the flow rate of glucose medium was 0.8 L/h.It was found that the exponential flow mode was better than the constant speed flow mode based on the study on glucose flow.The experimental results showed that the exponential flow rate set atμ=0.08 h-1 resulted in a maximum production intensity of organic selenium,which reached 12.55 mg/(L·h).Under the optimized conditions,the final concentration of yeast cell was 35.6 g/L,and the organic selenium content in the cell was 4937μg/g.Among them,72%of total selenium compounds were in the form of Se-methylselenocystein(3555μg/g).The final concentration of Se-methylselenocystein reached 8189μg/g based on the molecular weight conversion.

关 键 词：甲基硒代半胱氨酸 有机硒生产强度 流加发酵 比硒消耗速率 

分 类 号：TQ92[轻工技术与工程—发酵工程]