Front Matter

 

112 Introduction to Renewable Biomaterials

Lignocellulose

Carbohydrates Lignin

Composition

Degree of

crystallinity

XRD FTIR 13 CP/MASC NMR GPC

(^1) H NMR
(^31) P NMR HSQC HSQC,
Pyro-GC/MS
(^13) C NMR
Inter/intra-unit
bonding
Inter/intra-unit
bonding
Functional
groups
Structure Molecular weight Structure Composition
distribution
Figure 4.1Biomass characterization diagram shows common characterization techniques for
carbohydrates and lignin.
15% [12], to corn stover that is 6% [12], to some energy grasses such as switchgrass that
has levels of 3–7% [12]. Mineral levels of ash do vary by stalk versus leaf material, as well
as position in the stem and growing location of the plant. Another method to measure
ash content is to use thermogravimetric analysis equipment, where the sample is heated
on a balance pan to very high temperatures in an air environment. This method is
essentially microsampling the material, as analysis is limited to 10–50 mg of material.
Figure 4.1 shows the diagram of common characterization techniques for lignocellu-
lose. There are two major lignocellulosic components: (i) carbohydrates and (ii) lignin.
Both carbohydrate and lignin can be characterized by various techniques to learn about
their physiochemical characteristics. These information are useful in

• engineering plant biomass to have certain traits including (i) less recalcitrant and
  (ii) more drought resistant and/or


• designing biological and/or chemical pathways to degrade and/or convert plant
  biomass into valuable products.

4.7 Structural Cell Wall Analysis, What To Look For

The structural components of the cell wall of biomass are composed of a mixture

of carbohydrates (i.e., polysaccharides) and lignin closely integrated within the cell

wall. In order to fully utilize lignocellulose, robust analytical techniques for their

quintessential traits (Table 4.1) are required for analysis. Changes in carbohydrate and

lignin compositions, chemical structure, and functionality affect fiber properties and

ultimately product quality.

Recent imaging studies of the cell wall provided insight into the arrangement of

these compounds related to the biological synthesis of the cell wall [58]. Cellulose

is deposited as bundles within the cell wall of various diameters, dependent upon

the plant type, and their orientation controlled by microtubules. During deposition,