Characterization of a Novel Lutein Cleavage Dioxygenase, EhLCD, from Enterobacter hormaechei YT-3 for the Enzymatic Synthesis of 3-Hydroxy-β-ionone from Lutein

Round 1

Reviewer 1 Report

In this manuscript, the authors Wei et. Al. reported “Characterization of a novel lutein cleavage dioxygenase, EhLCD, from Enterobacter hormaechei YT-3 for the enzymatic synthesis of 3-hydroxy-beta-ionone from lutein”. 3-hydroxy-beta-ionone has several applications in fragrance, food and beverage industry. Also, enzymatic synthesis has several advantages over conventional chemical synthesis. Particularly environmentally friendly.  

• This manuscript is well written and easy to follow
• The authors determined the approximate molecular weight of the purified enzyme lutein cleavage dioxygenase, EhLCD, as well as studied the Reaction mechanism of lutein cleavage by EhLCD using ¹⁶O₂–H₂¹⁸O
• The authors also studied the effect of temperature, P^H, solvent, and metal ions on enzymatic cleavage of Lutein 

Overall, the manuscript is well written and the results are convincing. I recommend this manuscript for publication in Catalysts

Author Response

Dear Reviewer

Thanks for the comments and suggestions. The whole manuscript is carefully revised according to the instructions for authors of Catalysts. 

Author Response File: Author Response.docx

Reviewer 2 Report

In the study of Long and colleagues, best to their knowledge, a purified enzyme from Enterobacter hormaechei YT-3 was the first characterized bacterial lutein cleavage dioxygenase. In the last decades, interests in natural substances or the synthesis of valuable compounds via green technology have risen. The authors decided to purify a lutein cleavage dioxygenase from Enterobacter hormaechei YT-3 in order to obtain 3-hydroxy-β-ionone from lutein. Apart from enzyme purification, isotope-labelling experiments, and enzyme characterization were made. Optimum temperature, pH, stability, as well as, the impact of cations and organic solvents were assessed. In overall, the manuscript has been well written and supported with strong results.

I would only ask you to improve the quality of Figure 6.

Author Response

Dear Reviewer, 

Thanks for the comments and suggestions. The responses to the comments are listed as follows: Figure 6 has been replaced by the high quality figure.

Author Response File: Author Response.docx