【作者】 王晖；

【导师】 胡滨；

【作者基本信息】 河北工业大学 ， 生物化工， 2007， 硕士

【摘要】 Nisin是由34个氨基酸残基组成的短肽,对革兰氏阳性菌有抑制作用,在食品工业中广泛的被用作食品防腐剂。工业化生产nisin的方法主要为利用乳酸链球菌的微生物发酵法,Nisin的提取是目前nisin生产的关键步骤。本文对吸附法分离发酵液中nisin进行了研究,主要选用国产大孔树脂和离子交换树脂作为吸附剂,并对离子交换动力学热力学进行了研究。主要研究内容如下:1.研究了大孔树脂和离子交换树脂对发酵液中乳链菌肽的吸附解吸性能。对于大孔树脂,吸附量为:D4006:190000IU/g,H103:124000IU/g;70%乙醇酸水溶液为解吸剂,解吸率分别为38.4%和40.8%;动态吸附解吸试验中,D4006的穿透时间为43min,经过42.5h达到吸附平衡;H103穿透时间为85min,经过45.67h达到吸附平衡。Nisin解吸浓度的峰值均出现在解吸开始100min内。对于离子交换树脂,吸附量为:D113:120000IU/mL,D151:129000IU/mL;5%KCl为解吸剂,D113和D151的解吸率分别为48.6%、22%。静态吸附D113和D151的最终收率分别为45.6%、20.9%。对两种树脂的动态吸附及解吸进行了初步研究,在20h时达到吸附平衡;在2.5h时出现洗脱峰。测得D113解吸液nisin的比活力为15453IU/mg。2.研究了离子交换过程中不同影响参数对吸附动力学控制模型的影响。转速分别为50r/min、100r/min和150r/min时,吸附过程为颗粒扩散控制(PDC)。D113:25℃时为FDC控制;40℃、50℃时为PDC控制。3.对离子交换树脂D113的吸附热力学进行研究,得到:D113在25℃,40℃和50℃时的吸附等温线均符合Langmuir型平衡关系式。在25℃,40℃和50℃时吸附焓变大于零,但温度的影响并不显著。4.研究了表面活性剂对解吸率的影响。对D4006,加入2%(v/v)吐温-80时的解吸率为59.2%,解吸率提高20.8%,加入0.2%(g/mL)PEG20000的解吸率为61.8%,解吸率提高23.4%;对H103,加入2%(v/v)吐温-80时的解吸率为57.6%,解吸率提高16.8%,加入4%(g/mL)PEG20000的解吸率为60.4%,解吸率提高20.4%。更多还原

【Abstract】 Nisin is a bacteriocin of bactericidal activity against Gram positive bacteria and is commonly used as a food preservative in the food industry. At present, nisin is produced through fermentation by certain strains of Lactococcus lactis. It is the important step to separatie nisin from the fermentation broth. In the study, resins produced in China were chosen as the adsorbents. The kinetics and energetics of the anionic resins were studied.1. The adsorption and desorption of nisin from the fermentation broth by macroporous resins and anionic resins were studied. The adsorption quantities of the macroporous resin D4006 was 190 000IU/g and H103 was 124 000IU/g; 70%(v/v) ethanol solution (pH2～3) was chosen as the desorbent for nisin desorption; In the dynamic adsorption and desorption test, as for D4006,the pierce time was 43 min, and reached the balance time in 42.5h; as for H103,the pierce time was 85 min, and reached the balance time in 45.67h. The highest elute concentration of nisin appeared within 100min.The adsorption quantities of the anionic resin D113 was 120 000IU/mL and D4006 was 129 000IU/mL; 5%KCl (pH2～3) was chosen as the desorbent. The final recovery of nisin on D113 and D151 were 45.6% and 20.9%, respectively. In the dynamic adsorption and desorption test, the balance time was 20h and the highest elute concentration of nisin appeared in 2.5h. The activities of nisin separated by D113 was 15453IU/ml.2. The ion exchange kinetics for nisin onto D113 was developed. The results showed that it was the particle diffusion control (PDC) when 50r/min, 100r/min and 150r/min. As for D113, it was controlled by PDC at 40℃、50℃and by film diffusion control (FDC) at 25℃.3. The thermodynamics of nisin adsorption on D113 was studied. At 25℃、40℃and 50℃, the equilibrium data for the adsorption of nisin were correlated with the Langmuir type isotherm equations. The enthalpy of adsorption was above zero of D113 at 25℃、40℃and 50℃, the process of adsorption was an endothermic process. Temprature has little effect on the adsorption process.4. The effects of surfactant on on desorption of nisin from fermentation broth was studied. As for D4006, 59.2% and 61.8% of nisin was desorbed by using 2% (v/v)Tween-80 and 0.2% ( g ml-1) PEG20000, respectively. As for H103, with the addition of 2%(v/v)Tween-80 and 4% (g ml-1) PEG20000 the nisin desorption rates were 57.6% and 60.4%. Compared with the desorption rates without any surfactant, the nisin desorption rates increased approximately 20% both the two resins.更多还原