View
9.293
Download
4
Tags:
Embed Size (px)
Citation preview
Novozymes in brief
Two different pathways:
1. Large scale cassava focused production systems like in Asia producing ethanol for use a e.g. transport fuel
2. Small scale – e.g. integrated agro-forestry systems producing ethanol for use in cook-stoves, as well as misc. food, feed and other energy products
Cassava based ethanol in an African context
1. Reduce deforestation due to charcoal production
2. Reduce accidents and negative health effects relating to indoor use of kerosene, wood or charcoal
3. Improve access to affordable energy
4. Stimulate local agriculture through smallholder/outgrower schemes
Benefits of small scale agro-forestry systems producing ethanol to replace charcoal
• 100% family sector growers– Agro-forestry systems– Degraded & abandoned plots– Diverse mix of trees and crops– Increased food quantity and quality– Raw materials for energy products
• Community pre-processing centres – Buying, training, technical assistance, pre-
processing, storage, logistics• Fruit & Veg consumed locally• Cassava dried chips• Oilseeds raw plant oil• Beans dried & packed for cities• Waste animal feed and biofertilizer
• BioProcessing Centre– Production of ethanol
• Household cooking fuel– Production of Pure Plant Oil
• Diesel substitute in converted generators
• Cookstove Manufacturing Facility
5
Outline of a potential smallholder/outgrower based system
Smallholder agro-forestry concept with integrated food, feed and fuel production
The Fuel Ethanol Process
Raw Materials for Ethanol Production
• Ethanol can be fermented from sugars
• Sugars can be produced by enzymes from starchy raw materials
• Starchy raw materials can be any cereal grains or starchy plant roots
• Examples:
• Corn, wheat, millet, sorghum, rye, barley, rice, cassava
Starch in cassava
Protein middle lamella
Outer wall(-Glucan and pentosan)
Inner cell wall (-Glucan)
Starch granules
Protein matrix
General overview of starch conversion to ethanol
3 types of enzymes required
1. Viscosity reducing enzymes– Viscozyme Cassava R
– Viscozyme cassava C
2. Alpha-Amylase– Liquozyme SC, SC DS and 4X
3. Gluco-Amylase– Spirizyme Fuel
– Spirizyme Ultra
– Spirizyme Excel
Three stages where enzymes are added
Milling /Slurry make up Cooking Fermentation
Type of enzyme added
Viscosity reducing enzyme Alpha-Amylase Gluco-Amylase
Enzyme name
1. Viscozyme cassava R2. Viscozyme cassava C
1. Liquozyme SC2. Liquozyme SCDS
1. Spirizyme fuel2. Spirizyme ultra3. Spirizyme Excel
Main Purpose
Reduce viscosity due to non starch polymers
1. Reduce viscosity due to starch polymers
2. Converts starch to dextrin
To convert dextrin to glucose
Other Benefits
1. Enable mash to be pumped2. Avoids gel formation3. Lower heating and cooling cost
1. Processes starch to be suitable for fermentation
2. Enables better mixing of enzymes3. Avoids gel formation
Enables yeast to consume the glucose and generate ethanol
Working Temp
50-55°C 84-86°C 32-35°C
Ethanol yield from starch: Cassava example
Yields from 1 ton raw material
Cassava Roots Chips Starch
% Starch 25 65 85
100% theoretical
Ethanol, litres 180 468 612
93% efficiency
Ethanol, litres 167 435 569
Milling & Cook: Slurry formation and initial breakdown of starch
1. Grind cassava into smaller particles (flour)– Increase surface area (accessibility to the enzyme)
2. Mix flour with water to form a slurry – Form a uniform mixture– Add enzymes to reduce viscosity – Add enzymes to start transformation of flour into dextrin
3. Cook slurry at high temperature use jet or steam– Flour absorbs the hot water and becomes “mash”– Mash becomes thick (viscous) – becomes gelatinized
4. Hold at temperature – Allow time for enzymes to break starch into short chain dextrins
Initial breakdown of starch into shorter dextrin chains
Alpha-Amylase enzyme randomly cleaves large chain dextrins into a mixture of shorter chain dextrins
Alpha-amylase
Shorter dextrin chains
Large Dextrin chains
DP6DP4DP3DP2
Further breakdown of dextrins into fermentable sugars: Two main process options
• Pre-fermentation saccharification– Pre-fermentation saccharification in separate tank for a few
hours at optimal conditions
• Simultaneous saccharification and fermentation– Sugars are generated with the yeast present
– Occurs at typical fermentation conditions
Saccharification: Breakdown of dextrins into glucose
What does Gluco-Amylase do?
Gluco-Amylase breaks short chain dextrins into simple fermentable sugars that yeast can convert into ethanol
Long chain sugarsLong chain sugars(Dextrins)(Dextrins)
SimpleSimplesugarssugars
Typical cost breakdown for cassava-based ethanol production – example from Asia
How Novozymes can assist you
• Provide enzymes solutions designed for starchy raw materials – and including for cassava
• Share our vast global process experience with our customers
• Continuously develop new enzymes and process technologies
Thank Youfor your attention
Please visit our website
www.bioenergy.novozymes.com
Technical service contact: [email protected]