putA与vgb基因对反式-4-羟基-L-脯氨酸产量的影响

Effects of putA and vgb Genes on trans-4-Hydroxy-L-Proline Production

摘要:

反式-4-羟基-L-脯氨酸是在自然界中分布最广泛的一种羟脯氨酸，在医药、化工、食品和美容业等领域有广泛应用。为了在生物转化法生产反式-4-羟基-L-脯氨酸的过程中减少菌体对底物脯氨酸的降解，利用Red/ET同源重组系统敲除putA基因，并比较野生型菌株与缺失型菌株在不同培养基中的反式-4-羟基-L-脯氨酸产量，再引入vgb基因，考察该基因对反式-4-羟基-L-脯氨酸产量的影响。结果表明：putA基因的缺失能阻止菌体降解脯氨酸；碳源充足的情况下，GC培养基更有利于反式-4-羟基-L-脯氨酸的生产；putA基因缺失型菌株能将被消耗的脯氨酸全部转化为反式-4-羟基-L-脯氨酸；vgb基因的存在能显著提高反式-4-羟基-L-脯氨酸的产量。

Abstract:

Trans-4-hydroxy-L-proline is widely distributed in nature and applied in the pharmaceutical，chemical，food and cosmetic products. In order to interrupt the bacterial degradation of proline during the biosynthesis process of trans-4-hydroxy-L-proline，putA gene was deleted using Red/ET homologous recombination system. Wild types and mutants were cultured in GT and GC media，and the trans-4-hydroxy-L-proline yields were compared to obtain the optimal strain and medium. On the other hand，vgb gene was introduced into the cell and its effect on trans-4-hydroxy-L-proline production was studied. The results show that the knockout of putA gene can prevent the degradation of proline，and with an adequate supply of the carbon source，GC medium is better for producing trans-4-hydroxy-L-proline than GT medium. Moreover，all of the consumed proline can be transformed to trans-4-hydroxy-L-proline in putA deletion mutants. By contrast，the presence of vgb gene can significantly improve trans-4-hydroxy-L-proline production.