After alkaline pretreatment, cellulose contents in both straws of RNa and CNa increased by 11.56 and 7.20% respectively, while both hemicellulose and lignin contents decreased by 14.32% and 18.29% in rice straw, 20.65% and 26.65% for cotton straw respectively. Further treatment with either Fe-Co composite or H3PO4 induced significant reductions in cellulose, hemicellulose and lignin by 1.46-18.09%, 31.73-61.48% and 56.53-74.64% respectively, compared to the pristine straws. What can be the possible mechanism that cellulose contents are increasing. Please guide
Check your calculation of the percentage of cellulose, hemicellulose, and lignin. Were they calculate from the same batch of sample?
You should also consider yield of alkaline treatment. I think the percentages of each elements of both straws of RNa and CNa after alkali pretreatment are calculated by comparing the yield after pretreatment.
Vendy Prasetyo many thanks sir for your guidance. You mean we should check the weight loss and final yield of the substrate after pre-treatment?
To your second question, I would say yes, you should.
To answer your first question, it would be helpful to know how you are measuring the alpha-cellulose / hemicellulose / lignin contents.
TAPPI standards maybe?
The below mentioned researcher has many articles involving treatment of straws with NaOH. Look specially at the older articles. Happy new year.
https://www.researchgate.net/profile/Yehia_Fahmy
Dear Muhammad,
I would suggest you to follow the standard NREL's compositional analysis for estimating the biomass components. During initial stages of research, I happened to observe the same while I was estimating the compositions in my pre-treated biomass. It could be because, we usually estimate the composition from 1g of the biomass (both pre-treated and untreated). I am providing you with an example, which I feel may help you. Imagine pre-treating a stipulated quantity (100g of the biomass); Assume removal of 70% lignin and 80% hemicellulose during pre-treatment. It would consequentially result in the weight reduction of your biomass as well. Now, after pre-treatment, when you are considering the compositional analysis of 1g of your biomass, you are actually estimating the biomass devoid of a considerable quantity of hemicellulose and lignin, and it is not the same 1g (now, it is majorly cellulose), which you estimated prior to pre-treatment; it would have more cellulose than hemicellulose and lignin (since they have been removed). In my case, I observed great differences in weights between the pre-treated and untreated biomass samples.
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