摘要
二十碳五烯酸(eicosapentaenoicacid,EPA)因具有调节血脂、降低纤维蛋白、预防心血管疾病以及抗炎抗过敏的生理功能,被广泛应用于食品、医疗、化妆品以及饲料添加等领域。目前,EPA的需求日益增加,但是富含多不饱和脂肪酸(polyunsaturatedfattyacids,PUFAs)的鱼油等自然资源逐渐匮乏,利用改造的微生物菌种发酵生产EPA的方式成为主要趋势。本研究利用同源重组技术将Shewanella sp.SCRC2738的烯酰还原酶基因(enoyl-reductase,sh-ER)分别敲入Schizochytriumlimacinum SR21的ORFB-ER和ORFC-ER基因中,调控多不饱和脂肪酸合成的偏好性以提高EPA的产量。研究表明,sh-ER替换ORFB-ER基因的重组菌株(B-sh-ER)中EPA含量提高了85.7%,聚酮合酶(polyketidesynthases,PKS)途径相关基因转录水平明显上调。而sh-ER替换ORFC-ER基因的重组菌株(C-sh-ER)中PUFAs合成基本不变。在5 L发酵罐中放大培养后,B-sh-ER重组菌株总油脂提高28.7%,达到73.2 g/L;EPA产量提高71.6%,达到732.4 mg/L。本研究为促进裂殖壶菌PUFAs高产提供了新的策略,同时也为调控裂殖壶菌合成EPA提供了新的视角。
Eicosapentaenoic acid(EPA)is widely used in the fields of food,medical treatment,cosmetics and feed additives because of its physiological functions of regulating blood lipids,reducing fibrin,preventing cardiovascular diseases,anti-inflammatory and anti-allergic.At present,the supply of EPA cannot meet the market demand,due to the natural resources such as fish oil rich in polyunsaturated fatty acids(PUFAs)are gradually scarce.Therefore,more and more research focus on using the modified microbial strains to produce EPA.In this study,homologous recombination technology was used to knock the enoyl-reductase gene(sh-ER)of Shewanella sp.SCRC2738 into the ORFB-ER and ORFC-ER domains of Schizochytrium limacinum SR21,in order to regulate the preference for polyunsaturated fatty acid synthesis to increase the yield of EPA.The results showed that the EPA content of the B sh-ER strain increased by 85.7%and the transcriptional level of polyketide synthases(PKS)pathway related genes were significantly up-regulated.The synthesis of PUFAs in C-sh-ER strains presented little change.In 5 L fed batch fermentation,total lipids yield of the B-sh-ER strains increased by 28.7%reaching to 73.2 g/L;the EPA yield increased by 71.6%reaching to 732.4 mg/L.This study supplies a new strategy for promoting the high production of PUFAs and provides a novel perspective for regulating the synthesis of EPA in Schizochytrium sp.
作者
杨瑞雄
郑鑫
陆涛
赵誉泽
杨庆华
卢英华
何宁
凌雪萍
YANG Ruixiong;ZHENG Xin;LU Tao;ZHAO Yuze;YANG Qinghua;LU Yinghua;HE Ning;LING Xueping(College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,Fujian,China;Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources,Xiamen 361005,Fujian,China;The Key Laboratory for Chemical Biology of Fujian Province(Xiamen University),Xiamen 361005,Fujian,China)
出处
《化工学报》
EI
CAS
CSCD
北大核心
2021年第7期3768-3779,共12页
CIESC Journal
基金
国家自然科学基金重点项目(21736009)
国家自然科学基金面上项目(31871779)。
