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γ-L- Valley leucyl -L- cysteinyl glycine (γ-L-cysteinglycine, glutathione, referred GSH) is a tripeptide compound, its main industrial production pathways through microbial fermentation Further extraction , and is widely used in the clinical treatment of diseases and other aspects . GSH production and its application at home and abroad have been some studies , but its industrial production technology has been monopolized by a handful of foreign developed countries with relatively low GSH concentration and purity of domestic self - developed , has not yet been achieved industrial production , GSH resulting in the high market prices , the impact of the promotion and application of GSH . Through a lot of trials research , take the following ways to achieve a high yield and high purity of GSH , provide a theoretical reference for domestic industrial production of GSH . First, by the metabolism of sulfur-containing substances in the study of yeast cells in the process of transforming their metabolic pathways . Determining a suitable medium : 20g / L of glycerol , 10g / L yeast extract , 20g / L peptone , 0.05mol / L phosphate buffer , 13.4g/LYNB , 4 × 10 -4 g / L biotin , 0.05 mol / L L -cys ; the identified objective culture conditions : temperature of 28 ° C to -30 ° C , fully dissolved oxygen , the initial pH of 6.0 ; Based on this , after five days of fermentation , GSH yield could reach 6.0 g / L , to achieve a high yield of GSH . Then, according GSH mainly distributed in microbial intracellular , the permeability of the cell membrane or destruction of the cell wall to release characteristics can be changed by temperature or organics , and using GSH isoelectric point of about 5.93 it under acidic conditions with a positive charge , so that GSH will subjected to ion exchange with a cation resin and adsorbed by the resin , thus separating the GSH and other impurities . In addition , in order to obtain a more refined product , the experiment also ultrafiltration , nanofiltration technologies such as the introduction of the separation and purification process , GSH yield reached 90% purity reached 95% , to achieve the high purity of the GSH . Summary of GSH separation and purification process more complicated , and when the fermentation GSH concentration falls below a certain value , the purification process difficult . This experiment, by the above method to achieve a purification of GSH from the high yield of Pichia pastoris , and simplifies the purification step of the GSH to solve the problem of the presence of GSH industrialized production .
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