C. pasteurianum高产1,3-丙二醇菌株发酵条件的研究(Ⅱ)

确定了 1,3 丙二醇高产菌株 (Clostridium pasteurianum简写为CpN 3 8) 1,3 PD厌氧发酵最适 pH值、温度、时间、接种量分别为 7 0、3 0℃、40h、8% ;在最适发酵条件下 ,3 0L发酵罐中CpN 3 8菌株 1,3 PD产量为 49 0 7g/L ,生产率为 2 9 3 8g/ (L·d)。     

海洋低温BS041208菌株选育及发酵培养基的研究(Ⅱ)

建立了海洋低温蛋白酶菌株(Bacillussubtilis简写为BS041208)发酵最适pH值、温度、时间、接种量、通气量分别为5.0、14℃、48h、8%、150mL;在最适发酵条件下,BS041208菌株50L发酵罐中低温蛋白酶活性为1371.8U/mg。     

几种天然活性物质对食用肉抑菌保鲜作用的影响

利用天然可食用物质——绿茶(1.5%)、蔗糖(3%)(采用磷酸盐-乳酸缓冲系统配制),对冷却肉处理,然后进行冷藏保存[(8±1)℃,6d]。通过食肉微生物的生长繁殖速度、挥发性盐基氮含量和食肉浸出液pH值变化对其腐败过程加以监测。结果表明:在冷藏过程中:(1)由茶汁和蔗糖处理的食肉样品,在4d内均有较强的抑菌作用,可达75%;到6d时,抑制作用均减弱,蔗糖的抑制效果降至12.6%;(2)由蔗糖处理的样品,挥发性盐基氮(TVB-N)含量非常稳定,具有一定的抑制蛋白质降解功能;而茶汁处理的样品TVB-N含量有所增加,抑制蛋白质降解作用不明显;(3)食肉浸出液的pH有明显改变,蔗糖处理的浸出液pH稳定,其余浸出液pH值均有所增加,顺序为蔗糖<茶汁<对照。     

Parameter Optimization for Enhancement of Ethanol Yield by Atmospheric Pressure DBD-TreatedSaccharomyces cerevisiae简

In this study, Saccharomyces cerevisiae （S. cerevisiae） was exposed to dielectric barrier discharge plasma （DBD） to improve its ethanol production capacity during fermenta- tion. Response surface methodology （RSM） was used to optimize the discharge-associated pa- rameters of DBD for the purpose of maximizing the ethanol yield achieved by DBD-treated S. cerevisiae. According to single factor experiments, a mathematical model was established using Box-Behnken central composite experiment design, with plasma exposure time, power supply volt- age, and exposed-sample volume as impact factors and ethanol yield as the response. This was followed by response surface analysis. Optimal experimental parameters for plasma discharge- induced enhancement in ethanol yield were plasma exposure time of 1 rain, power voltage of 26 V, and an exposed sample volume of 9 mL. Under these conditions, the resulting yield of ethanol was 0.48 g/g, representing an increase of 33% over control.     

海洋低温BS041208菌株选育及发酵培养基的研究(Ⅰ)

以从渤海和黄海分离出的400株在低温条件下生长良好的菌株为出发菌株,利用常规筛选方法筛选出2株低温蛋白酶产生菌(Bacillussubtilis)。经UV、DES、NTG、EMS、LiCl单独及复合诱变,选育出一株(BS041208)蛋白酶高产突变株。通过单因素实验,确定了BS041208菌株蛋白酶发酵培养基为:玉米淀粉糖0.7%,豆饼粉1.6%,K2HPO40.8%,KH2PO40.6%。该突变株低温蛋白酶产量为867.5U/mg。