does thermal pretreatment leads to increase in hemicellulose and lignin of a lignocellulosic biomass ??
Nope.. There is no evidence that suggests the inter-conversion of Cellulose and lignin to cellulose and vice versa. what happens after thermal pretreatment is the hemicellulose comes out in liquid phase along with some cellulose depends on the pretreatment condition and solvent.
May be you have not expressed your question in the right way?
When you extract some components, the other increase their percentage on biomass, but they are not created, only their proportion has changed.
Thank you Deepak and Maam. Yes, I want to know whether during compositional analyis of lignocellulosic biomass, is there an increase in the percentage of hemicellulose and lignin and decrease in cellulose ??
It is a mathematical question (rule of mixtures). If 3 components must add up to 100% (X+Y+Z= 100) and one of them is being removed, its proportion decreases and the percentage of the other two must increase to reach 100.
Hemicellulose and lignin are the first to degrade, especially if the biomass has a high mineral content. Look to papers regarding torrefaction for more details.
I agree with all researcher, hemicellulose is easily breakable to its subcomponents due to branched chain structure in xylose, arabinose, galactose, acetic acid and some of its part catalytically converts to furfural in presence of dilute acid or high steam.
In general the chemical composition of any biomass represent the % of different component present in biomass which altogether summarize to 100,
100 = Extractive+ Cellulose+ Hemicellulose+ Lignin+ Ash+ Protein
In general, pretreatment basically removes the recalcitrance nature of biomass by disrupting and removing of these components. Hence, after pretreatment the composition of some component decrease while some increase.
For example in thermal pretreatment, firstly hemicellulose, followed by small amount of lignin and cellulose.
As I did the experiment, microwave pretreatment had more effect on cellulose content of lignocellulosic biomass and not much contributed in increases of hemicellulose. Meanwhile the lignin reduction was significant and considerable.
No, After thermal pretreatment ( above 170 temp) hemicellulose dissolve. liquid extract consist reducing sugar (pentose/Xylose) mostly from hemicellulose.
No, it will not. Hemicellulose is the most reactive component of biomass samples and usually the first to thermally degrade during treatment. Hope this helps.
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