Novel Propagation Strategy of Saccharomyces cerevisiae for Enhanced Xylose Metabolism during Fermentation on Softwood Hydrolysate

Round 1

Reviewer 1 Report

The study entitled Novel propagation strategy of Saccharomyces cerevisiae for enhanced xylose metabolism during fermentation on softwood hydrolysate his interesting, well written

The authors have successfully propagated the yeast cells with high yield using ethanol and glycerol mixture but the major comment is the authors didn’t show the main effect of propagated cells on the sugar consumption of the softwood hydro lysate to complete the scenario and achieve the main aim of this work

The authors are advised to show these data

Some others comments:

• The abstract should be arranged as the data inside the Ms, it could be misunderstood as the enhanced results of xylose consumption is based on the newly described propagation strategy.
• L 13, strain name should be italic
• L14-15, please delete these sentences as these are not common for type strains, the authors have to calcify the specificity of these information’s to which type of Saccharomyces cells
• L42, L85 CO2 please subscript 2
• L56, L58, L94L104, L109, L128, L130, L138, all scientific names should be italic
• L156-159, please show the condition strategy for yeast propagation. Is this just inoculation for one incubation time? How long?
• L205 why the concentration of medium components are too high for example urea conc is 23.49 g/L while other media only 3.08? Please clarify the reasons for all
• Tables 1,2 please show the statistical analysis data
• Fig 1 please clarify YPS and YPEG on the figures for easer clarification
• Table 3 please describe the data as only 3 effective figures and merge the unit with the first column parameters
• The propagation method consumed 174 g/L of ethanol, the authors should discuss the economics of this strategy as they compared with other studies using yeast extract for example.
• The conclusion should be shorten to almost half of the present , please show only the conclusion

Author Response

Please see attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript presents a unique study on propagating Saccharomyces cerevisiae in order to improve xylose metabolism during ethanol fermentation. The research presented has been well-designed and is further improved by the authors using an actual industrial softwood hydrolysate to test their propagation process. The only aspect of the manuscript that require minor edits would be to shorten the "Introduction" section. 

Author Response

Please see attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have addressed almost of the raised points up to their available data.