High Cell Density Cultivation of Lactococcus lactis ssp. Lactis for the Production of Nisin and Its Recovery

• Main Authors: Hsien Wen Fu, 薛文富
• Other Authors: Lee C. K.
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/74634527189557863135

碩士 === 國立臺灣科技大學 === 化學工程系 === 89 === Nisin is a primary metabolite produc of Lactococcus lactis ssp. Lactis. Nisin has a strong antimicrobial activity against Gram-positive organisms and is used commercially in food preservation. MRS medium was used for the production of Nisin by batch cultivation of Lactococcus lactis ssp. Lactis. The cell cultivation pH was controlled at pH 6.5 without areation. The cell concentration could grow to 14 OD600 and the Nisin concentration could reach 14199 IU/ml. The optimum time for harvesting the culture is at the end of log phase. The pH of culture should adjust to pH 2 to protect Nisin from degradation by protease. Eight repeated batches fermentations were easily achieved by using microfiltration. The cell concentration could reach 31 OD600 and the Nisin concentration could reach 21,527 IU/ml. The Nisin productivity could be enhanced 1.86 fold compared to batch fermentation. When continuous feeding cultivation carried out by continuous removal of fermentation broth using MF system, the Nisin productivity could be enhanced 5~6 fold. Seventy four percent of proteins of fermentation culture could be removed by ultrafiltration using a MWCO 10k membrane. The Nisin was totally retained by 10k UF membrane. The recovered Nisin was purified 3 fold. Nisin in the fermentation broth exists as a tetramer as confirmed by GPC.