Studies on the Production of Cyanophycin in Recombinant Lactococcus lactis Carrying Cyanophycin Synthetase Gene and the Medium Optimization by Using Response Surface Methodology

• Main Authors: Ding-Chung Wang, 王鼎中
• Other Authors: Tsuei-Yun Fang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/17853515955659904833

碩士 === 國立臺灣海洋大學 === 食品科學系 === 100 === Abstract Our laboratory had cloned the gene of cyanophycin synthetase into pNZ8149 plasmid, and then expressed in lactic acid bacteria to produce cyanophycin, and found that 30℃ is the optimum growth temperature and the optimal induction was carried out under 250 ng/mL of nisin for five hours after the OD600 reached 0.4. However, recombinant lactic acid bacteria grew in M17-L (M17 medium plus 0.5% lactose) medium, and only resulting in low cyanophycine production. In addition, the M17-L medium is very expensive. TB-L (TB medium plus 0.5% lactose) was used to replace the M17-L for the growth of recombinant lactis acid bacteria under the best induction time of 3 h. yeast extract, lactose and amino acids were choose to search optimal condition, and then use response surface methodology for statistics and analysis. We found that lactose plays an important role in cyanophycine yield. Yeast extract shows a negative correlation with Cyanophycine yield. The optimal TB-L medium (TB-L-OPT) contains 1.2% tryptone,1.0% lactose,0.2% aspartic acid,0.3% arginine and 0.4% glycerol. Compared to M17-L medium, TB-L-OPT medium can reduce more than 50 % of the cost and improve the cyanophycine yield up to 1.5 times or more.