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zyqdyk

木虫 (正式写手)

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注册: 2007-03-29
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专业: 环境微生物学

[交流] 虫虫们帮看下还有希望吗？

我7月底投了一篇bioresource technology 今天把修改意见发给我了，第一次投稿不太懂，想问问虫友没还有希望吗？请大家给我分析分析感激不尽！
以下是修改意见：
Reviewer #1:
General comments.

The objective of this work is to optimize several factors such as temperature, time, catalyst concentration and solid-liquid ration in both dilute sulfuric acid hydrolysis and alkali-pretreatment of the solid residue obtained after acid hydrolysis. However, the authors used a classical design in which the response is investigated for each factor in turn whilst the other are held constant. Maybe the use of a factorial design would have been more useful. Using a factorial design it is possible to estimate both main effects and interactions in contrast to the classical design (use by authors in this work).

Specific comments

Methods and materials

How were cellulose and hemicellulose content in switchgrass determined?

The authors state that fermentations were carried out "with several replicates".
How many replicates?
However standard deviations of replicates were not given. They should have been included in the figures.

In page 6 the paragraph "the concentration of glucose and ethanol……..(GC) for the ethanol" is not clear and should be rewritten.
I understand that sugars were determined by HPLC and ethanol by GC. In fermentations of hydrolyzates from acid hydrolysis glucose and ethanol were determined every 4 h and xylose every 24 h, and in fermentations of enzymatic hydrolyzate both glucose and ethanol were determined every 4 h.

Results

In the first experiments (when authors studied the effect of temperature in the range 120-135 ºC), what initial condition (time, acid concentration and solid liquid ratio) were used?
Regarding fermentation of enzymatic hydrolysates and taking into account the ethanol concentration reached in this work, the authors should consider using a higher amount of substrate in the enzymatic hydrolysis tests in order to obtain as high sugars as possible and so higher ethanol concentrations.
On the other hand, the concentrations of both yeast extract and peptone used in fermentation are too high

Figures.

Print every figure on a separate page.

Figures 3 and 4 seem to be included in the same page.

There are some mistakes in x-axis title, for example: t/ºC instead t (ºC) in figure 1; concentration of dulite instead of dilute in figure 2; time/h instead time (h) in figure 5, etc.

Figure captions should include much information. Symbols used in graphs don't match with those used in figure captions.

Other comments

Please insert one space between the figures and the units. For example

250 ml instead of 250ml.
60 ºC instead of 60ºC.
14 h instead 14h.
20 g/l instead 20g/l.
10 atm instead 10atm. Etc.

Use rpm instead rev/min, M instead mol/l and g/lh instead g/l.h

There are some spelling mistakes that should be corrected:

Pag 5,
line 6.- Cellulase instead of "Celluclase)
line 11 insert space "ATCC 26921)and"
line 14 "hydrolyisis, the specific" instead "hydrolysis , the specific).
Page 6,
Line 17 insert space "(HPLC)for".
Page 9,
Line 28 Hemicellulose instead "Hemiclullose".
Pag 17. Figure captions. Cellulose instead "cellucose".

Reviewer #2: The paper concerns a pretreatment for increasing ethanol production from Switchgrass. The study is well performed and the methodology used using a kind of factorial design to find the optimal temperature, residence time, solid concentration and acid concentration. However, many researchers have already investigated the effect of pretreatment for ethanol production using Switchgrass in bench scale research. Even if your substrate were different with others, I would not find any new scientific discovery and merit from your manuscripts.
After reviewing the paper, I have decided that your manuscript could be reconsidered for publication should you be prepared to incorporate major revisions. If you submit a revised manuscript, it will be treated as a new submission and sent out again for review. When preparing your revised manuscript, you are asked to carefully consider the reviewer comments which are provided below.

ABSTRACT:
The quality of writing of the abstract is significantly worse than that of the main body of the paper. A SHORT SUMMARY (some result) OF THE WHOLE PAPER SHOULD FORM THE ABSTRACT. The abstract should be written.
- INTRODUCTION:
Introduction should be carefully reconstructed (context and grammatical errors). What the authors focus on is not emphasized. Finally, all of references need to be updated.
Example)
P4, Line 9-15, need to be given a reference.
P4, Line 23, move to M&M section.
- MATERIALS AND METHODS:
In particularly, preparation and characterization conditions were poorly defined in the M&M section.
P4, Line 58, what else? Is there any standard method for sugar analysis? If you had, please describe in detail.
P5, Line 3, The material is ground to extremely small pieces, which is of course necessary due to the small reactors used, but is this also expected to be used in a real process? If so, how will this affect the energy demand for milling, and if not how will larger pieces influence the pretreatment results?
P5, Line 4. Authors determined the cellulase activity (P7, Line 9-12), please clarify the specific range of cellulase activity. and, check the Novozyme 188 unit out.
P5, Line 45 and P6, Line 26, For acid and alkaline pretreatements, the authors should clarify the operating systems (reactor, total volume, working volume, control system whatever) in order to let the readers judge of your process.
P6, Line 34, Why is the enzymatic hydrolysis performed with washed substrate at very low concentration (1 wt %) and with relatively high enzyme dosage (30 FPU/ g cellulose)? I understand that this eliminates the end product inhibition but how is it related to real ethanol production and how can you be sure that the optimal conditions for pretreatment are optimal for ethanol production at more realistic dry matters? Some companies are developing high-gravity enzyme liquefaction technology allowed them to go from 10 percent or 15 percent dry matter in the pretreated material to above 30 percent.
P6, Line 34 and P6, Line 53, I guess rich hemicellulosic sugar are presented in the hydrolyzate after pretreatment, I was wondering if your cellulosic enzyme could give a good yield of a monomeric hemicellulose sugars. Typically, hydrolysis of hemicellulose requires a number of hemicellulosic enzyme, and several enzyme activities needs to be combined. If you had the table of a mass balance after hydrolysis with cellulosic enzyme, please show them in you manuscript.
P7, Line 6, Per analytical method, additional information should be provided about how the sugar analysis and calculations are done, including 1) that no pH adjustment was done on the samples prior to HPLC (GC) analysis, 2) how polymeric sugar amount was calculated (example: C(%)= show the conversion factor of cellulose and hemicellulose), 3) what standard(s) were used to quantify / calibrate the HPLC (GC).
- RESULTS AND DISCUSSIONS
The Results and Discussion section needs a lot of work. In particular, it is hard for reviewer to judge the result of pretreatment section without pretreatment operation conditions. and, it would be good to conduct research with the combined severity function which incorporates reaction time, temperature and acid concentration, will provide a useful means of trading off the combined effects of these three variables on total sugar yields. Then add a final plot with your data plotted verses the combined severity factor (CS=log(Ro)-pH), since authors varied both acid concentration and severity.
In conclusion, the manuscript must be significantly rewritten so that it can be evaluated on its technical merit. Therefore, I want to encourage authors to try improving upon your work and its written description so that it has a much better chance of being accepted the next time around.

Editor's comments:

- paragraph 2 should be Materials and methods
- conclusions : 100 words max, do not itemize the text

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