Module 5 Flashcards
T/F: Biorefinary processes are operate opposite of petroleum refineries, which produce multiple fuels and chemicals from one feedstock, petroleum.
False: they are analogous
What other industry/sector do we have to be aware of when implementing a biorefinery plant?
Agriculture industry (occupy land to grow biofuel vs. crops)
T/F: healthy, consumable crops should be used as biofuel
False: where possible, use land that would not be used for agriculture to grow biomass
List 3 products of biorefinery from biomass:
- Fuels (ethanol, biodiesel)
- Solvents (acetone, butanol, tetrahydrofuran)
- Bulk chem (succinic acid, sucrose)
- Plastics (thermoplastic, starch)
- Fibers (cellulosic fibers)
- Fine chem (isosorbides, lactic acid esters)
- Oils (corn oil/triglycerides)
T/F: compostable = may be anerobically digested
False: companies can call biomass compostable but they may not be entirely converted (ie. bamboo)
Why is bamboo difficult to digest/break apart?
Structural fibers = tensile strength, tough
List 4 examples of feedstock for biorefinery
- Sludge (ww)
- Organic waste: households
- Org waste: industry
- Manure + org waste from agr
Name 4 benefits of biorefinery
- Reduces dependence on fossil fuels
- Reduction on env pollution
- Economic benefits
- Can be delocalized: mindful of Indigenous communities (no huge oil pipes!)
How is biorefinery more economically sound? (3 things)
- Cheaper to use wastes
- Stimulates rural/agr economy
- Market for “low” qual plants
(General econ growth)
T/F: Prior to the 1930s, bulk chemicals produced from biomass
True
What is a platform profile?
A flowchart showing the different chemical products of [biorefinery], or other conversion processes (and how they’re produced)
List an example of a top platform bio-based chemical (from US Dep of E)
*Top substances that have the most econ value
- Succinic acid
- 3-hydroxypropionic acid
- Itaconic acid
- Ethanol
- Lactic acid
- Glycerol
- Sorbitol
- Levulininc acid
T/F: Sucrose is a major biorefinery feedstock, especially from biobutanol
False: bioethanol, not biobutanol
How is sucrose juice extracted?
Mechanical crushing of sugar cane (bagasse residue); stripping/pulping of sugar beets
What are two plant sources of sucrose
Sugar cane (brazil)
Sugar beets (EU)
_________ enzymes hydrolyze sucrose to ________ and ________.
Invertase
Glucose
Fructose
What is the % composition of bagasse (sugar cane)?
45-55% cellulose
20-25% hemicellulose
18-24% lignin
Process of turning sugar cane to energy
Milling > bagasse > combustor > energy
Process of turning sugar cane to sugar
Sugar cane > milling > juice > sugar production > sugar
Process of turning sugar cane to bioplastics
Sugar cane > milling > juice > bioplastics (ie. polydroxyalkanoate)
Process of turning sugar cane to bioethanol
Milling > juice > fermentation > distillation > bioethanol
Major feedstock of bioethanol in the US
Cornstarch (95%)
Cornstarch: mixture of linear and branched homopolymers of ________.
Glucose
Cornstarch: ___% water-soluble ________, __% water-insoluble ________.
20%, amylose
80%, amylopectin
Difference betwe amylose and amylopectin?
Amylose: linear polymer (10^2 - 10^5 gluc units)
Amylopectin: shorter chains (17-23 units) of glucose to form branched structure of (10^4 - 10^7 units)
Bond between branches and main chain of amylopectin
alpha(1-6)-glycosidic linkage
Between 1C of glucose in branch and 6C of glucose in main chain
Bond between units in main chain of amylopectin and amylose
alpha(1-4)-glycosidic linkage
Between 1C of one unit and 4C of another unit
What are the three disadvantages of chem conversion of starch?
- Glucose yield = 50% of theoretical
- Undesirable by-products (furans, furfurals)
- Needs corrosion-resistance equipment
Acid hydrolysis (starch): pH of ___, ___ - ___ºC, dilute acid
pH of 2
140-150ºC
Major disadvantage of enzyme growth
Slow growers, need more time to convert (more time = larger volume)
What type of enzyme is required to cleave the alpha(1-4) bond?
- a-amylase (endoenzyme) > dextrin
- b-amylase (exoenzyme) > cleaves non-reducing end
- glucoamylase (exoenzyme) > cleaves non-reducing end
What type of enzyme is required to cleave the alpha(1-6) bond?
- Pullulanase
What does “debranching” do?
Cleaves alpha(1-6) linkage (takes apart branches)
With our feedstock being starch, what is the overall process of biomass conversion?
- Milling (if we need to shred, ground)
- Gelatinization
- Saccharification & fermentation
- Distillation
4a) ethanol
4b) Stillage
4bi) + Heat = distiller’s dried grain and solubles (DDGS)
What happens in the gelatinization process in conversion of starch?
Water is absorbed and starch becomes gelatinous; adding heat reduces its viscosity
(15-50% solids, pH 6-6.5, heat to 105ºC 2-3min)
T/F: only beta-amylase is added to the mixture to liquify/dextrinize the gelatinous glucose
False: alpha-amylase and beta-amylase are both added
T/F: During the saccaraification & fermentation step, glucoamylase and pullulanase are both added to the mixture
True
T/F: Sacc. & ferm. step: 60ºC for 60h, pH 4.5
True
Composition of lignocellulosic biomass feedstocks
30-50% cellulose
20-40% hemicellulose
15-25% lignin
5-35% “other”
T/F: Ash, resins, fats, fatty acids, etc make up 3-10% of lignocellulosic biomass
True
T/F: Switchgrass is not typically used as a biorefinery feedstock because it’s a slow grower and uses a lot of water
False: IS used as feedstock, fast growers, uses little water
T/F: Hemicellulose content in soft and hard wood is abt the same
True
What differentiates hardwoods from softwoods?
Composition of hemicellulose
T/F: Softwoods have higher percentages of glucomannan (C6 sugars) in their hemicellulose than hardwoods, and hardwoods have higher glucuronoxylan (C5 sugars) percentages in their hemicellulose than softwoods
True
Why is hardwood called “hardwood”?
Hardwood = C5 sugars in hemicellulose = don’t have too many enzymes available that can break these linkages
Can water enter in lignocellulosic biomass easily?
No: H-bonds betw hemicell and lignin = very difficult for water to get inside
T/F: Lignin holds reigid cellulose fibrils in place
False: Lignin is found in cell walls, entangles and cross-links w/ hemicellulose
T/F: Cellulose is the most abundant natural polymer on Earth
True
Main difference between cellulose and starch structure
Both are chains of glucose; cellulose = alternating glucose units are flipped upside-down; linked by beta(1-4) bonds
T/F: In cellulose, chains are stabilized by internal H-bonds
True
In ________ area of polymer, there is ___-________ between ________ and water.
Amorphous
H-bonding
Cellobiose
Hemicellulose is a highly ________, generally non-________ _________
Branched
Crystalline
Heteropolymer
Hemicellulose has sugar residues of ____ - ____ units of 5-C (D-xylose, L-arabinose) and 6-C (D,L-galactose, D-mannose) tings
500 - 3000
_________ dominate in hardwood
Xylenes
________ dominate in softwoods (ie. galactose, glucose, mannose)
Galactomannans
Lignins give ________ to plants and _______ _______ in walls. It is made of a random copolymer of ________ (C9 units)
Strength
Fills space
Phenylpropane
What is main diff betw lignin and cellulose?
Aromatic structures are present in lignin which make it significantly harder to break down
What are two counter arguments for converting biomass to biofuel
- Need a sustainable way of discarding of waste from process (turn to fertilizer)
- Agricultural land vs. land for feedstock
What does the number written on the grade of the gas pumps signify?
Ethanol is mixed with gasoline: the number signifies the carbon content on the grade of the gas
T/F: Most bio-ethanol produced globally is used towards food and beverages
False: automotive and transportation
List an application of ethanol
- Fuel (80%)
- Chemical feedstock (platform chemical)
List a benefit of using ethanol in fuel
- less NO2 and CO than gas (40-50% less GHGs)
- cleaner, longer life
- less C deposits in engines
T/F: Cars manufactured in 1800s were originally designed for ethanol
True
T/F: Despite its versatility, ethanol cannot be converted to bioplastics
False
T/F: Since bioethanol is an up-and-coming industry, many companies are joint/collaborative
True
T/F: Canada is one of the countries that contribute the most to global ethanol production
False: USA (54%) and Brazil (30%) are the highest
The US Dep of E Independence and Security Act (EISA) mandated achieving national production of 36B gallons of biofuel (to be added to ________) by 2022, of which 21B gallons must be derived from ________ feedstocks (ie. lignocellulose)
gasoline
sustainable
List a major bioethanol producer from starch in the US
- POET
- ADM
- Valero Renewable Fuels
- Green Plains
T/F: GreenField Ethanol, one of the largest producers of ethanol in the world, has yet to install a plant in Canada
False: we alr have several (Suncor-St Clair, Tiverton, Johnstown, etc)
List a major bioethanol producer from cellulose
- Logen
- SunOpta (France)
- Tembec (Temiscaming, QC)
- POET-DSM Emmetsburg, Iowa)
- DuPont (Nevada, Iowa)
What is cellulastic ethanol?
Fuel that derive from waste materials (ie. wood residues, woods grown on land)
T/F: In the process of producing ethanol from sugar cane, some of the solid-liquid co-product is placed in a centrifuge and separated to make fertilizer, which is then used commercially
True
List the characteristics of an ideal microbe for ethanol production
- Ferments broad range of carb substrates rapidly
- High eth prod yield (>90% theoretical)
- High eth tolerance (>40 g/L)
- Low levels of by-products (ie. organic acids, glycerol)
- Osmotolerant (withstands high osm pressure at high sugar conc.)
- Temp tolerant
T/F: Not every single organism involved in production of ethanol can handle all carbohydrate substrates
True
List 3 examples of microorganisms involved in the commercial production of bioethanol
Yeasts:
- S. cerevisiae (gluc, fruct, malt, maltotri, xylulose) > facultative
- S. carlsbergensis (‘’)
- S. rouxii (gluc, fruct, malt, sucr)
Bacteria:
- Clostridium spp
- C. thermocellum > thermophilic
- C. thermohydrosulfuricium > thermophilic
T/F: Saccharomyces is the most ideal type microbe to use to produce ethanol
False: it is ideal, but has a narrow substrate range (ie. gluc, fruc, malt). It will not use cellulose, hemicellulose, cellobiose, or most pentoses
What is ATP?
Adenosine Tri-phosphate (energy carrier)
T/F: In fermentation there is a net production of 2 ATP molecules and they are used to regenerate bacteria itself
True
________ ethanol yield is ___% based on the weight of ________.
Theoretical
51.1%
Glucose
We SHOULD get a max of ___% of the theoretical yield of ethanol from glucose from the two moles of ____ produced from fermentation. In reality, we get 90-95% of the _________ yield because we have ethanol ________ of cell growth
86%
ATP
theoretical
inhibition
___ - ___% of ethanol is toxic to yeast depending on the strain. ___% ethanol totally inhibitory.
8-18%
11%
T/F: More resistant yeasts have shorter, unsaturated fatty acids and can make more when exposed to ethanol.
False: resistant yeasts gave LONGER unsaturated fatty acids
T/F: The problem of osmotic pressure is more prevelant in a CSTR.
False: more problematic in a batch reactor (we’re never at steady-state, so high [A] = high release of osmotic pressure)
Glycerol, a by-product of ethanol production, accumulates in the largest amount as an ________ metabolite. To avoid large amounts of glycerol production, ________ ________ should be ________.
osmoregulatory
osmotic pressure
minimized
T/F: Separation of fusel oils and higher alcohols (isobutanol and isoamyl) are more important for potable/pharmaceutical-grade ethanol
True
For ethanol production, the temperature must be maintained at ___ºC. It is an ________ reaction, and complete fermentation of ___% glucose results in a temp increase of ___ºC.
35
exothermic
18%
20
What are the 3 major stages in the conversion of biomass to alcohol?
- Conversion of biomass to fermentable sugars
- Fermentation (conversion of sugars to alcohol)
- Recovery (distillation, ethanol storage)
T/F: In the distillation phase of alcohol recovery, the distillate contains ~5% water, and is only used to blend with gasoline
False: the liquid mixture before distillation contains 5%, and pure alcohol is mixed with gasoline or used for pharmaceutical use
What are the two ways in which alcohol is separated from the mixture?
- Use of absorbants (ie. starch, zeolites)
- Azeotropic distillation with pentane benzene (more expensive)
What is stillage?
Residue from the distillation. 1L of ethanol produces 10-15L of stillage.
T/F: Nitrogen is the largest component of stillage after alcohol distillation from fermented sugar cane juice
False: organic matter is the most abundant component
What is the main drawback of SHF?
Accumulation of glucose inhibits enzyme (cellulase) activity (3g gluc/L = 75% decrease in enz activity)
T/F: In SHF, cellulase activity is optimal at 45-50ºC and ethanol production is optimal at 30-37ºC
True
What is SHF?
Separate Hydrolysis Fermentation: hydrolysis of starch to glucose occurs separate of the fermentation process
What are the basic steps of SHF?
Raw materials > pretreatment > saccharification > Fermentation (add S. cereviceae) > Distillation > Ethanol
What is SSF?
Simultaneous Saccharification & Fermentation: enzymes and yeast are added to ONE reactor
T/F: In SSF, enzymes are manufactured in the same reactor where hydrolysis and fermentation occur
False: enzymes manufactured in a separate system
What is a major drawback of SSF?
Cellulase inhibited by ethanol (30 g/L ethanol decreases activity by 25%)
T/F: SHF hydrolysis rates are faster than SSF. It also produces higher ethanol yields, lowers enzyme loading, and lowers capital costs
False: opposite process are true
What are the basic steps of SSF?
Raw materials > pretreatment > saccharification & fermentation (add S. cereviceae and enzyme) > Distillation > Ethanol
What is SSCF?
Simultaneous saccharification and co-fermentation: ferments hemicellulose (C5 sugars) at the same time as C6 sugars. Hemicellulose is added with enzymes to the sacch. & ferm. step of SSF to make SSCF
What is CBP?
Consolidated bioprocessing: enzyme production and fermentation occurs in the same reactor using recombinant microbes.
What is a major drawback currently of CBP?
Gene modification = poor growth, low ethanol, low ethanol tolerance, lactic/acetic acid, byproducts
T/F: CBP lowers capital costs
True
