In this work, wheat straw (WS) was used as a lignocellulosic substrate to investigate the influence of pH on enzymatic saccharification. The optimum enzymatic hydrolysis occurred at pH range 5.8 -6.0, instead of 4.8 -5.0 as has been widely reported in research. Two enzymes cocktails, Celluclast® 1.5L with Novozymes 188, Cellic® CTec2 and endo-1, 4-β-Xylanase, were used for the pH investigation over a pH range of 3.0 -7.0. The highest concentration of total reduced sugar was found at pH 6.0 for

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... ll the different enzymes used in this study. The total reduced sugar produced from the enzymatic saccharification at pH 6.0 was found to be 7.0, 7.4 and 10.8 (g L -1 ) for Celluclast® 1.5L with Novozymes 188, endo-1, 4-β-Xylanase and Cellic® CTec2, respectively. By increasing the pH from 4.8 to 6.0, the total reduced sugar yield increased by 25% for Celluclast® 1.5L with Novozymes 188 and endo-1, 4-β-Xylanase and 21% for Cellic® CTec2. The results from this study indicate that WS hydrolysis can be improved significantly by elevating the pH at which the reaction occurs to the range of 5.8 to 6.0. Thank you very much for sending the reviewers comments on our manuscript. We also would like to thank the reviewers' precious time to review our manuscript. We have prepared a new version of this manuscript, which has been substantially modified addressing all points raised by the reviewers. We feel that the current version has been markedly improved and hope that it would be now acceptable for publication. We Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation provide below a detailed explanation on how we have addressed the points raised by the reviewers. Thank you very much. Yours Sincerely, Corresponding Author Reviewer #1: There is no comment on this paper. This paper is that describes how to increase the productivity of bioethanol and is thought to be helpful to researchers who study Wheat Straw as a biomass. Authors respond: The authors would express their gratitude to the reviewer for his/her time taken to review the paper. Reviewer #2: The authors described how they found the new optimized conditions of pH range for highest yield of total reduced sugar from enzymatic saccharification of WS. Based on this optimization, they observed higher optimized pH range than the widely reported values. The results seem to be of considerable interests for the related field and the manuscript is relatively well written. However, I believe that the manuscript should be clear for the following questions and comments prior re-review. Abstract In this work, wheat straw (WS) was used as a lignocellulosic substrate to investigate the influence of pH on enzymatic saccharification. The optimum enzymatic hydrolysis occurred at pH range 5.8 -6.0, instead of 4.8 -5.0 as has been widely reported in research. Two enzymes cocktails, Celluclast® 1.5L with Novozymes 188, Cellic® CTec2 and endo-1, 4-β-Xylanase, were used for the pH investigation over a pH range of 3.0 -7.0. The highest concentration of total reduced sugar was found at pH 6.0 for all the different enzymes used in this study. The total reduced sugar produced from the enzymatic saccharification at pH 6.0 was found to be 7.0, 7.4 and 10.8 (g L -1 ) for Celluclast® 1.5L with Novozymes 188, endo-1, 4-β-Xylanase and Cellic® CTec2, respectively. By increasing the pH from 4.8 to 6.0, the total reduced sugar yield increased by 25% for Celluclast® 1.5L with Novozymes 188 and endo-1, 4-β-Xylanase and 21% for Cellic® CTec2. The results from this study indicate that WS hydrolysis can be improved significantly by elevating the pH at which the reaction occurs to the range of 5.8 to 6.0.