基于面包酵母中海藻糖提取工艺优化及菌株筛选的高密度培养工艺  

Optimization of Extraction Process for Trehalose from Baker's Yeast for Strain Screening and High Density Culture

作　　者：洪厚胜[1] 窦冰然 郭会明 HONG Housheng;DOU Bingran;GUO Huiming(College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China;College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China)

机构地区：[1]南京工业大学生物与制药工程学院,江苏南京211816 [2]南京工业大学化学与分子工程学院,江苏南京211816

出　　处：《食品科学》2018年第6期122-129,共8页Food Science

基　　金：国家高技术研究发展计划(863计划)项目(2012AA021201)

摘　　要：确定使用酶-3,5-二硝基水杨酸(3,5-dinitrosalicylic acid,DNS)法作为酵母胞内海藻糖定量测定方法,通过微波-浸提法对活性干酵母胞内海藻糖进行提取,采用单因素试验以酵母中海藻糖含量为参考指标优化该工艺中的微波功率、微波时间、三氯乙酸浓度、三氯乙酸体积、浸提温度、浸提时间,在此基础上对微波功率、微波时间、三氯乙酸浓度、三氯乙酸体积、浸提温度5个因素进行正交试验,优化后工艺条件为:针对1.5 g活性干酵母,微波功率231 W、微波时间40 s、三氯乙酸浓度0.7 mol/L、三氯乙酸体积40 m L、浸提温度55℃、浸提时间150 min。使用该工艺得到的活性干酵母中的海藻糖含量为280.15 mg/g,相对于优化前提高了15.2%。同时,利用该优化后工艺在现有面包酵母菌种中筛选出了一株高产海藻糖的菌株。在50 L自吸式发酵罐中将该菌株进行流加发酵,采用糖蜜进行溶氧反馈流加时最大酵母湿质量浓度为198.34 g/L,将流加工艺进行改进,提出称质量补料的流加方法将糖蜜、尿素、磷酸二氢铵作为流加营养源,实验发现发酵后最大酵母湿质量浓度可提高到264.82 g/L,相对于原工艺提高了33.52%,达到了面包酵母高密度培养的要求。发酵过程中将乙醇体积分数控制在0.7%~1.0%之间,将有效提高酵母湿质量浓度且保证其发酵力在650 m L/h以上,且工艺稳定性良好。The microwave-assisted extraction of trehalose was optimized using one-factor-at-a-time and orthogonal array design methods.Intracellular trehalose in yeast cells was determined by3,5-dinitrosalicylic acid(DNS)method after hydrolysis by trehalase.The optimum conditions for extracting trehalose from1.5g of active dry yeast were determined to be extraction at55℃for150min using40mL of0.7mol/L trichloracetic acid as the extraction solvent with microwave treatment duration of40s at231W power.Under these conditions,the yield of trehalose was280.15mg/g,15.2%higher than that before optimization.Furthermore,one of the10baker’s yeast strains preserved in our laboratory was selected for high yield production of trehalose.In a50L self-priming fermenter,the selected strain was used to perform fed-batch fermentation.The maximum wet yeast biomass was198.34g/L by using feedback control of dissolved oxygen concentration through feeding molasses.By feeding a predetermined amount of molasses,urea and phosphoric acid as nutrient source,the maximum wet yeast biomass was increased to264.82g/L,which was increased by up to33.52%compared with the original procedure and suggested high density culture of baker’s yeast.In the fermentation process,the alcohol content(V/V)was controlled between0.7%and1.0%,thereby effectively improving wet yeast biomass and simultaneously ensuring that the fermentation power is over650mL/h,and the modified process was confirmed to stable.

关 键 词：面包酵母 海藻糖 称质量补料 乙醇体积分数 

分 类 号：TS201.3[轻工技术与工程—食品科学]