CB2E: Converting Cellulose Biomass to Ethanol Lab Kit

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Converting Cellulosic Biomass to Ethanol

Massachusetts Institute of Technology

Department of Biology

TW 2014 Biofuel

Converting Cellulosic Biomass to Ethanol

Activity from CB2E from Great Lakes Bioenergy Research Center, Golden, Colorado

https://www.glbrc.org/education/classroom-materials/cb2e-converting-cellulosic-biomass-ethanol

Summary |

One abundant, cheap and under-utilized source of raw material for the production of biofuel (bioethanol) are cellulose and lignin, which are the major components of plant cell walls and are very hard to breakdown. In this lab you will investigate the challenge of converting various cellulosic biomasses first into glucose, and then into ethanol. In this experiment we will use a defined 3-step process of (1) pretreatment, (2) enzymatic treatment, and (3) yeast fermentation of the sample to produce ethanol, and we will look at the efficiency and challenges of the process. We will start with mechanical force, chemicals and heat to separate the lignin and cellulose from raw plant material, and then use various enzymes isolated from living organisms to biochemically breakdown cellulose into glucose. Finally we will add yeast to ferment that product and measure the ethanol produced to determine effectiveness of the overall process.

In this inquiry-based activity, students will see which team can produce the most ethanol per gram of dry cellulosic biomass. Each team will pick a cellulosic biomass sample, break it down, convert it into glucose, and then into ethanol through the processes described above. Students will track the conversion process by measuring glucose and ethanol levels at key stages. This data collection by the various teams will help determine which biomass source (feedstock) and pretreatment methods (mechanical, heat, pH) and enzymes are most effective at producing sugars and ethanol and students will test their predictions. Students will use this information to develop explanations for why some samples produced more sugar and ethanol than others, and consider the implications for biofuel producers.

Background Information

Teacher manual, student manual and other support materials including PowerPoint, graphic organizers, and worksheets for Experiment CB2E (Converting Biomass to Ethanol) from Great Lakes Bioenergy Research Center, Golden, Colorado are available at https://www.glbrc.org/education/classroom-materials/cb2e-converting-cellulosic-biomass-ethanol

Objectives (from CB2E)

Test predictions about how variables (biomass type and grinding method) affect conversion into sugars and ethanol
Trace the transformation of cellulose into glucose and then ethanol
Assess the action of cellulase enzymes on cellulose
Measure the conversion of sugars to ethanol
Use sugar and ethanol readings to evaluate initial predictions and draw conclusions about the effects of treatment variables.

Materials in the Kit

designed for class of 24 working in groups of 3, and available upon request to Mandada@mit.edu), the kit will include:

4 Vernier LabQuest LabQ2
8 Vernier Ethanol Sensors ETH_BTA
1 roll Plumbers tape
4 TRUEbalance Blood Glucose Meters
(1 other Blood Glucose Meter)
Blood Glucose Strips for TRUEbalance or other meter (specific to meter) 100 strips/class
Parafilm
Disposable pipettes (30 for 1 class)
Celluclast (Cellulase) in aqueous solution

For cellulase (C2730) the optimal pH range is 4.5 - 6.0, and the optimal temperature range is 50 - 60°C.
Produced by submerged fermentation of a selected strain of the fungus Trichoderma reesei and catalyzes the breakdown of cellulose into glucose, cellobiose, and higher glucose polymers.

50mL falcon tubes, 2 packages of 20
Printed copy of student manual
Printed copy of teacher manual

Materials provided by the school

Weigh boats
Electronic Balance
Grinder for biomass samples
Scissors, shears, saw for cutting biomass
25 or 50 ml graduates
600 ml beakers
Hot plates
Thermometer
Blender to cut up Biomass Samples, such as Ninja Kitchen System Pulse (BL201) Grinder or similar product
Other enzymes if desired (pectinase, amylase)

Procedure

Studentand TeacherManuals for CB2E available at https://www.glbrc.org/education/classroom-materials/cb2e-converting-cellulosic-biomass-ethanoland single copies are included in the kit.

Possible Extensions:

use different cellulases to determine if one is more effective than another at cellulosic digestion (Accellerase, Cellulase from other Trichoderma species.