Download NARA 5 Cellulose Hemicellulose and LigninName

NARA 5 Cellulose Hemicellulose and Lignin
Name_____________________________
1. Name some plant materials that are used to produce biofuels
2. What kind of energy is stored in plant biomass?
How it got there.
Following is an image of a plant tissue that shows multiple cells with distinctly visible cell walls.
What part of the plant cell is used to generate biofuel?
The three primary components of plant cell walls are cellulose,
hemicellulose, and lignin.
The image is a plant cell wall that depicts cellulose, hemicellulose and
lignin. The different components of the plant cell wall of a typical
hardwood tree consisting of about 25% lignin and 75% cellulose and
hemicellulose:
3. Why do plants might form lignin?
Why might this be a good investment of their energy?
Biofuel production uses the celluloses and hemicelluloses and not the lignin.
4. What difficulties are encountered in accessing and using cellulose and hemicellulose in biofuel production.
Pretreatment:
5. Why it is necessary to pretreat lignocellulosic biomass
6. List two forms of pretreatment in terms of their advantages and disadvantages.
Fermentation
•Fermentation is the process by which an organism such as a yeast takes in sugars, uses the energy contained
within them, and changes them into alcohols.
7. Name a yeast that is used to produce isobutanol.
Human Model of a plant cell wall:
•Assign approximately ½ of the class to be cellulose, ¼
hemicellulose and ¼ lignin.
Remember if you are an H, C or L.
•Celluloses form lines of 4-6 students and link arms.
Hemicelluloses does the same, but in lines parallel to each
other.
•The lignins surround the hemicellulose and cellulose lines.
The lignins place their hands over and through the
cellulose/hemicellulose lines, so that the lignins' arms are
reaching through and across the lines.
•The visual should be of lines of cellulose and hemicellulose
surrounded by a lignin web.
This is an approximation of the compounds that make up a
plant cell wall.
Biomass Conversion
Name_______________________________
This activity will allow you to act out symbolic representations of the steps of the biomass conversion process.
Part 1
Your group will get sugar cubes that you must coat the top half with chocolate.
The chocolate should be allowed to dry onto the sugar cubes.
The sugar cubes represent the cellulose and hemicellulose components (bunches of individual sugar molecules
bonded together) of plant cell walls and the chocolate represents the lignin. Biofuel production uses the
celluloses and hemicelluloses and not the lignin.
Part 2
You are engineers and are assigned the task of separating the lignin from the other constituents. You will need
to save each separated component for future use. (The task of separating the sugar cubes from the chocolate
may prove more difficult that adding the chocolate!)
Part 3
Once the "lignin" has been removed, you will now demonstrate the next part of the process, hydrolysis. This
step is the breakdown of the bonded sugar compounds into individual sugar molecules and will be represented
by dissolving the sugar cubes in hot water. CAUTION: This step involves hot liquid.
Place your sugar cubes in the hot water and stir if necessary to dissolve the cubes. The dissolution represents the
breakdown of the cellulose and hemicellulose compounds.
Note that the cloudiness or quantity of chocolate in the water indicates how well they succeeded in separating
the lignin from the starches!
Part 4
Once the sugar cubes are dissolved, the next step of the process is fermentation, or the conversion of sugars to
alcohols. This step will be represented by the addition of yeast organisms (cocoa krispies) to the slurry. The
gradual color change that should ensue represents the gradual process of fermentation carried out by these
organisms.
•Hydrolysis is the breaking up of polysaccharides (starches – in this case cellulose and hemicellulose) into
monosaccharides. Hydrolysis can use enzymes or chemicals that break the bonds between individual sugar
molecules.
•Fermentation is the process by which an organism such as a yeast takes in sugars, uses the energy contained
within them, and changes them into alcohols.
Biomass Conversion
Name_______________________________
Questions:
What made the removal of lignin (chocolate) more difficult than adding the chocolate?
How was Part 2 similar to and different from the actual removal of lignin?
Describe hydrolysis:
How was hydrolysis was represented in the activity?
How is this representation both accurate and inaccurate?
Different yeasts can have different alcohol outputs (i.e. ethanol or isobutanol).
How was fermentation represented?