枯草芽孢杆菌ls-45发酵法制取玉米肽的研究

Production of Corn Peptide by Fermentation with Bacillus Subtilis ls-45

经过单因素试验和响应面综合试验,确定了枯草芽孢杆菌(Bacillus subtilis)ls-45发酵生产玉米多肽的最佳发酵条件:接种量12%,40目玉米蛋白粉,底物浓度5%,初始pH8.0,装液量100 mL/500 mL三角瓶,培养温度41℃,摇床转速180 r/min,发酵时间63 h。在此条件下玉米肽得率达到最大为82.7%。并对制得的玉米肽进行了初步的分离纯化,经截留分子质量104u的中空纤维柱超滤,得到分子质量在104u左右的超滤液,其回收率为86.3%,超滤液经SephadexG-25柱分离纯化和相对分子质量分布的测定,共洗脱出4个峰,其玉米肽各级分的相对分子质量分别大致为5128、3715和1513。

The conditions for producing corn peptide by fermentation with Bacillus subtilis ls-45 were optimized by adopting the response surface method based on single factor tests.Results show the optimal conditions are inoculum size of Bacillus subtilis ls-45 12%,corn crushed in 40 meshes,substrate concentration 5%,pH 8.0,liquid volume 100 mL/500 mL conical beaker,fermentation temperature 41 ℃,rotation speed 180 r/min,and fermentation time 63 h.The corn peptide yield rate reaches 82.7% under the conditions.The gained corn peptide was purified by using hollow fiber ultrafiltration column and a ultrafihrate with molecular weight of 104 u was producedthe recovery rate is 86. 3 %. The ultrafihrate was further purified by SephadexG - 25 column and the distribution of molecular weight was analyzed, and four peaks emerged. Results show the relative molecular weights of the corn peptides in all levels are 5128, 3715 and 1513.