Enzymatic production oftrans-4-hydroxy-l-proline by proline 4-hydroxylase

Trans-4-hydroxy-l-proline (Hyp) is a useful chiral building block for production of many nutritional supplements and pharmaceuticals. However, it is still challenging for industrial production of Hyp due to heavy environmental pollution and low production efficiency. To establish a green and efficient process for Hyp production, the proline 4-hydroxylase (DsP4H) fromDactylosporangiumsp. RH1 was overexpressed and functionally characterized inEscherichia coliBL21(DE3). The recombinantDsP4H withl-proline as a substrate exhibitedK(m),k(cat)andk(cat)/K(m)values up to 0.80 mM, 0.52 s(-1)and 0.65 s(-1)center dot mM(-1)respectively. Furthermore,DsP4H showed the highest activity at 35 degrees C and pH 6.5 towardsl-proline. The highest enzyme activity of 175.6 U mg(-1)was achieved by optimizing culture parameters. Under the optimal transformation conditions in a 5-l fermenter, Hyp titre, conversion rate and productivity were up to 99.9 g l(-1), 99.9% and 2.77 g l(-1) h(-1)respectively. This strategy described here provides an efficient method for production of Hyp and thus has a great potential in industrial application.

Automated summary

This study presents a green and efficient production process for Hyp by overexpressing DsP4H enzyme and optimizing culture parameters, achieving high yields and conversion rates.