Improved production of trans-4-hydroxy-l-proline by chromosomal integration of the Vitreoscilla hemoglobin gene into recombinant Escherichia coli with expression of proline-4-hydroxylase
vgb gene was integrated into the chromosome of recombinant Escherichia coli expressing the gene of proline-4-hydroxylase. VHb expression solved the oxygen limitation in fermentation and finally improved trans-4-hydroxy-l-proline production. vgb gene chromosomal integration is an efficient approach to improving oxygen transfer to cells during fermentation.