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Hugang, China

Zou X.,East China University of Science and Technology | Zou X.,Southwest University | Zeng W.,Yidu HEC Biochem. Co. | Chen C.-F.,East China University of Science and Technology | And 6 more authors.
Biotechnology and Bioprocess Engineering | Year: 2010

Improvement of Erythromycin A (Er-A) production and purity by metabolic engineering of the industrial erythromycin-producing strains Saccharopolyspora erythraea strians ZL1004 and ZL1007, in which the amounts of tailoring enzymes EryK (a P450 hydroxylase) and EryG (an S-adenosylmethionine-dependent O-methyltransferase) for biotransformation of Erythromycin D to Er-A were modulated, was performed in a 50 L fermentor. Addition of 15 g/L of corn steep liquor to the medium increased Er-A production; maximum Er-A production was 8,196 U/mL at 191 h, which was 81.8% higher than that of control (4,507 U/mL at 184 h). Er-B impurities were completely eliminated, whereas Er-C impurities were only 153 U/mL at 191 h. Analysis of intra- and extracellular metabolites and key enzyme activities in central carbon metabolism revealed that the pool of TCA cycle intermediates was enhanced by the addition of corn steep liquor and induced an increase in erythromycin biosynthesis. There were no significant differences between strains ZL1004 and ZL1007 regarding Er-A production and impurity accumulation. Compared to wild type strain, Er-A production was improved by 23.9% while Er-C was reduced by 83.9% and Er-B was completely eliminated. Furthermore, fermentation of recombinant strain ZL1004 was successfully scaled up from laboratory scale (50 L fermentor) to industrial scale (25 and 132 m3), with similar levels of Er-A production and purity obtained. © 2010 The Korean Society for Biotechnology and Bioengineering and Springer-Verlag. Source

Zou X.,East China University of Science and Technology | Zou X.,Southwest University | Li W.-J.,Yidu HEC Biochem. Co. | Zeng W.,Yidu HEC Biochem. Co. | And 3 more authors.
Bioresource Technology | Year: 2011

An assessment of seed quality on erythromycin production by recombinant strain Saccharopolyspora erythraea ZL1004 was investigated in 15 l fermenter. Adding 10 g/l corn steep liquor and 30 g/l soybean flour in seed medium were beneficial to improve cell growth, and the maximal biomass reached 36% at 40 h. Enzyme activity in cell showed that the maximal protease and minimum amylase were appeared in this stage. Compared with the control in 50 l fermenter, the cell metabolism with inoculation of the optimized seed cultivation was obviously quicker, and physiological response such as oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER) were also improved. The maximal erythromycin A production was 9160. U/ml at 215 h, which was increased by 21.63% with respect to the control. It was the first report to integrate cell growth characteristics and physiological response method to assess the seed quality for erythromycin production. © 2010 Elsevier Ltd. Source

Zou X.,East China University of Science and Technology | Zou X.,Southwest University | Li W.-J.,Yidu HEC Biochem. Co. | Zeng W.,Yidu HEC Biochem. Co. | And 4 more authors.
Applied Biochemistry and Microbiology | Year: 2013

The physiology of feeding ammonium sulphate in erythromycin biosynthesis phase of Saccharopolyspora erythraea on the regulation of erythromycin A (Er-A) biosynthesis was investigated in 50 L fermenter. At an optimal feeding ammonium sulphate rate of 0. 03 g/L per h, the maximal Er-A production was 8281 U/mL at 174 h of growth, which was increased by 26. 3% in comparison with the control (6557 U/mL at 173 h). Changes in cell metabolic response of actinomycete were observed, i. e. there was a drastic increase in the level of carbon dioxide evolution rate and oxygen consumption. Assays of the key enzyme activities and organic acids of S. erythraea and amino acids in culture broth revealed that cell metabolism was enhanced by ammonium assimilation, which might depend on the glutamate transamination pathway. The enhancement of cell metabolism induced an increase of the pool of TCA cycle and the metabolic flux of erythromycin biosynthesis. In general, ammonium assimilation in the erythromycin biosynthesis phase of S. erythraea exerted a significant impact on the carbon metabolism and formation of precursors of the process for dramatic regulation of secondary metabolites biosynthesis. © 2013 Pleiades Publishing, Ltd. Source

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