Green Macroalgae Hydrolysate for Biofuel Production: Potential of Ulva rigida

Round 1

Reviewer 1 Report

This manuscript entitled " Green macroalgae hydrolysate for biofuels production: potential of Ulva rigida" is an original article that investigated the application of green macroalgae Ulva rigida was by its decomposed using commercial hydrolytic enzymes, which resulted in 23 ± 0.6 g then followed by fermentation using yeast (Saccharomyces cerevisiae) and ethanol concentration production was 9.55 ± 0.20 g.L^-1. The study also determined that the most favorable incubation conditions for S. cerevisiae to produce ethanol were as follows: non-sterilized environment, lack of enrichment, and inoculum volume of 118 mg.L^-1, and the efficiency was 80.78%. The ethanol o/t ratio tested for was as follows: 52.25% for Scheffersomyces stipitis, 63.20% for Candida guilliermondii, 70.49% for Kluyveromyces marxianus, and 82.87% for S. cerevisiae.

Introduction:

The introduction was written well in an excellent survey of the related literature, starting with the history of fossil biofuel and then its associated issues by depletion and overuse with limited resources and then mentioned the three different generations of biofuel and the advantages of using algae (seaweeds) as a feedstock of carbohydrates in the production of bioethanol by fermentation using different strains of yeasts and fungi and their related limiting factors of bioethanol production. The entire introduction included 63 relevant references.

Materials and Methods

This part of the manuscript is written without any statistical analysis of the data and also some missing parts as follows:

Line 126: All incubation conditions during the experiment should be included in details such as temperature range, daily illumination, date of the experiment, open pond outdoor or indoor?, and the mixing techniques. Is it air bubbles or a paddle wheel?

Line 128: what is DM refer to?

Line 139: what is the reference for the total sulfate method?

Line 160: Ulva should be italic

Line 176: Why did you enrich the hydrolysate? With both organic and inorganic nitrogen sources? And what is the reference?

Results and Discussion:

Using seven tables and five figures the data were tabulated and illustrated but with essential corrections as following

Line 206: sp not italic

Line 207: U. rigida should be italicized. Kindly check the entire manuscript for similar issues, and it is labeled in the attached file.

Line 214: where is the standard error for the measured biochemical parameters? For table 1 and table 2?

Line 272: What is chlorure!!!!

Line 278: formulas should moved to the materials and methods part

Line 288: The scientific name mentioned at first as full name then abbreviated (Ulva fasciata should be U. fasciata)

Line 384: The line marck and width for S. cerevisiae are not similar in fig 4.b and fig 4.c.

Line 423:  P. stipites, S not capital, and it will be better if the legend is included in the figure, not in the caption.

 sp. and spp. NOT italic

Conclusions:

The conclusion was clearly written and stated the aim and the final results of the experiments.

References:
all scientific names in the references are not italics and some references are all Capitalized in the title

Statistical analysis, error bars, and standard error values should be included in manuscript, figures, and tables respectively.

Comments for author File: Comments.pdf

check the attached file for highlighted texts 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

The suggested revisions are in the attached word file.

Comments for author File: Comments.pdf

The manuscript would be suitable for publication after a few minor revisions of the English language

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thank you for your corrections