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CHEE 342 > Module 5 > Flashcards

Module 5 Flashcards

1
Q

T/F: Biorefinary processes are operate opposite of petroleum refineries, which produce multiple fuels and chemicals from one feedstock, petroleum.

A

False: they are analogous

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2
Q

What other industry/sector do we have to be aware of when implementing a biorefinery plant?

A

Agriculture industry (occupy land to grow biofuel vs. crops)

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3
Q

T/F: healthy, consumable crops should be used as biofuel

A

False: where possible, use land that would not be used for agriculture to grow biomass

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4
Q

List 3 products of biorefinery from biomass:

A
  • 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)
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5
Q

T/F: compostable = may be anerobically digested

A

False: companies can call biomass compostable but they may not be entirely converted (ie. bamboo)

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6
Q

Why is bamboo difficult to digest/break apart?

A

Structural fibers = tensile strength, tough

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7
Q

List 4 examples of feedstock for biorefinery

A
  • Sludge (ww)
  • Organic waste: households
  • Org waste: industry
  • Manure + org waste from agr
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8
Q

Name 4 benefits of biorefinery

A
  • Reduces dependence on fossil fuels
  • Reduction on env pollution
  • Economic benefits
  • Can be delocalized: mindful of Indigenous communities (no huge oil pipes!)
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9
Q

How is biorefinery more economically sound? (3 things)

A
  • Cheaper to use wastes
  • Stimulates rural/agr economy
  • Market for “low” qual plants
    (General econ growth)
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10
Q

T/F: Prior to the 1930s, bulk chemicals produced from biomass

A

True

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11
Q

What is a platform profile?

A

A flowchart showing the different chemical products of [biorefinery], or other conversion processes (and how they’re produced)

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12
Q

List an example of a top platform bio-based chemical (from US Dep of E)

A

*Top substances that have the most econ value

  • Succinic acid
  • 3-hydroxypropionic acid
  • Itaconic acid
  • Ethanol
  • Lactic acid
  • Glycerol
  • Sorbitol
  • Levulininc acid
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13
Q

T/F: Sucrose is a major biorefinery feedstock, especially from biobutanol

A

False: bioethanol, not biobutanol

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14
Q

How is sucrose juice extracted?

A

Mechanical crushing of sugar cane (bagasse residue); stripping/pulping of sugar beets

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15
Q

What are two plant sources of sucrose

A

Sugar cane (brazil)
Sugar beets (EU)

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16
Q

_________ enzymes hydrolyze sucrose to ________ and ________.

A

Invertase
Glucose
Fructose

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17
Q

What is the % composition of bagasse (sugar cane)?

A

45-55% cellulose
20-25% hemicellulose
18-24% lignin

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18
Q

Process of turning sugar cane to energy

A

Milling > bagasse > combustor > energy

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19
Q

Process of turning sugar cane to sugar

A

Sugar cane > milling > juice > sugar production > sugar

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20
Q

Process of turning sugar cane to bioplastics

A

Sugar cane > milling > juice > bioplastics (ie. polydroxyalkanoate)

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21
Q

Process of turning sugar cane to bioethanol

A

Milling > juice > fermentation > distillation > bioethanol

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22
Q

Major feedstock of bioethanol in the US

A

Cornstarch (95%)

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23
Q

Cornstarch: mixture of linear and branched homopolymers of ________.

A

Glucose

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24
Q

Cornstarch: ___% water-soluble ________, __% water-insoluble ________.

A

20%, amylose
80%, amylopectin

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25
Q

Difference betwe amylose and amylopectin?

A

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)

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26
Q

Bond between branches and main chain of amylopectin

A

alpha(1-6)-glycosidic linkage

Between 1C of glucose in branch and 6C of glucose in main chain

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27
Q

Bond between units in main chain of amylopectin and amylose

A

alpha(1-4)-glycosidic linkage

Between 1C of one unit and 4C of another unit

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28
Q

What are the three disadvantages of chem conversion of starch?

A
  • Glucose yield = 50% of theoretical
  • Undesirable by-products (furans, furfurals)
  • Needs corrosion-resistance equipment
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29
Q

Acid hydrolysis (starch): pH of ___, ___ - ___ºC, dilute acid

A

pH of 2
140-150ºC

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30
Q

Major disadvantage of enzyme growth

A

Slow growers, need more time to convert (more time = larger volume)

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31
Q

What type of enzyme is required to cleave the alpha(1-4) bond?

A
  • a-amylase (endoenzyme) > dextrin
  • b-amylase (exoenzyme) > cleaves non-reducing end
  • glucoamylase (exoenzyme) > cleaves non-reducing end
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32
Q

What type of enzyme is required to cleave the alpha(1-6) bond?

A
  • Pullulanase
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33
Q

What does “debranching” do?

A

Cleaves alpha(1-6) linkage (takes apart branches)

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34
Q

With our feedstock being starch, what is the overall process of biomass conversion?

A
  1. Milling (if we need to shred, ground)
  2. Gelatinization
  3. Saccharification & fermentation
  4. Distillation
    4a) ethanol
    4b) Stillage
    4bi) + Heat = distiller’s dried grain and solubles (DDGS)
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35
Q

What happens in the gelatinization process in conversion of starch?

A

Water is absorbed and starch becomes gelatinous; adding heat reduces its viscosity

(15-50% solids, pH 6-6.5, heat to 105ºC 2-3min)

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36
Q

T/F: only beta-amylase is added to the mixture to liquify/dextrinize the gelatinous glucose

A

False: alpha-amylase and beta-amylase are both added

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37
Q

T/F: During the saccaraification & fermentation step, glucoamylase and pullulanase are both added to the mixture

A

True

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38
Q

T/F: Sacc. & ferm. step: 60ºC for 60h, pH 4.5

A

True

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39
Q

Composition of lignocellulosic biomass feedstocks

A

30-50% cellulose
20-40% hemicellulose
15-25% lignin
5-35% “other”

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40
Q

T/F: Ash, resins, fats, fatty acids, etc make up 3-10% of lignocellulosic biomass

A

True

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41
Q

T/F: Switchgrass is not typically used as a biorefinery feedstock because it’s a slow grower and uses a lot of water

A

False: IS used as feedstock, fast growers, uses little water

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42
Q

T/F: Hemicellulose content in soft and hard wood is abt the same

A

True

43
Q

What differentiates hardwoods from softwoods?

A

Composition of hemicellulose

44
Q

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

A

True

45
Q

Why is hardwood called “hardwood”?

A

Hardwood = C5 sugars in hemicellulose = don’t have too many enzymes available that can break these linkages

46
Q

Can water enter in lignocellulosic biomass easily?

A

No: H-bonds betw hemicell and lignin = very difficult for water to get inside

47
Q

T/F: Lignin holds reigid cellulose fibrils in place

A

False: Lignin is found in cell walls, entangles and cross-links w/ hemicellulose

48
Q

T/F: Cellulose is the most abundant natural polymer on Earth

A

True

49
Q

Main difference between cellulose and starch structure

A

Both are chains of glucose; cellulose = alternating glucose units are flipped upside-down; linked by beta(1-4) bonds

50
Q

T/F: In cellulose, chains are stabilized by internal H-bonds

A

True

51
Q

In ________ area of polymer, there is ___-________ between ________ and water.

A

Amorphous
H-bonding
Cellobiose

52
Q

Hemicellulose is a highly ________, generally non-________ _________

A

Branched
Crystalline
Heteropolymer

53
Q

Hemicellulose has sugar residues of ____ - ____ units of 5-C (D-xylose, L-arabinose) and 6-C (D,L-galactose, D-mannose) tings

A

500 - 3000

54
Q

_________ dominate in hardwood

A

Xylenes

55
Q

________ dominate in softwoods (ie. galactose, glucose, mannose)

A

Galactomannans

56
Q

Lignins give ________ to plants and _______ _______ in walls. It is made of a random copolymer of ________ (C9 units)

A

Strength
Fills space

Phenylpropane

57
Q

What is main diff betw lignin and cellulose?

A

Aromatic structures are present in lignin which make it significantly harder to break down

58
Q

What are two counter arguments for converting biomass to biofuel

A
  • Need a sustainable way of discarding of waste from process (turn to fertilizer)
  • Agricultural land vs. land for feedstock
59
Q

What does the number written on the grade of the gas pumps signify?

A

Ethanol is mixed with gasoline: the number signifies the carbon content on the grade of the gas

60
Q

T/F: Most bio-ethanol produced globally is used towards food and beverages

A

False: automotive and transportation

61
Q

List an application of ethanol

A
  • Fuel (80%)
  • Chemical feedstock (platform chemical)
62
Q

List a benefit of using ethanol in fuel

A
  • less NO2 and CO than gas (40-50% less GHGs)
  • cleaner, longer life
  • less C deposits in engines
63
Q

T/F: Cars manufactured in 1800s were originally designed for ethanol

A

True

64
Q

T/F: Despite its versatility, ethanol cannot be converted to bioplastics

A

False

65
Q

T/F: Since bioethanol is an up-and-coming industry, many companies are joint/collaborative

A

True

66
Q

T/F: Canada is one of the countries that contribute the most to global ethanol production

A

False: USA (54%) and Brazil (30%) are the highest

67
Q

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)

A

gasoline
sustainable

68
Q

List a major bioethanol producer from starch in the US

A
  • POET
  • ADM
  • Valero Renewable Fuels
  • Green Plains
69
Q

T/F: GreenField Ethanol, one of the largest producers of ethanol in the world, has yet to install a plant in Canada

A

False: we alr have several (Suncor-St Clair, Tiverton, Johnstown, etc)

70
Q

List a major bioethanol producer from cellulose

A
  • Logen
  • SunOpta (France)
  • Tembec (Temiscaming, QC)
  • POET-DSM Emmetsburg, Iowa)
  • DuPont (Nevada, Iowa)
71
Q

What is cellulastic ethanol?

A

Fuel that derive from waste materials (ie. wood residues, woods grown on land)

72
Q

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

A

True

73
Q

List the characteristics of an ideal microbe for ethanol production

A
  • 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
74
Q

T/F: Not every single organism involved in production of ethanol can handle all carbohydrate substrates

A

True

75
Q

List 3 examples of microorganisms involved in the commercial production of bioethanol

A

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

76
Q

T/F: Saccharomyces is the most ideal type microbe to use to produce ethanol

A

False: it is ideal, but has a narrow substrate range (ie. gluc, fruc, malt). It will not use cellulose, hemicellulose, cellobiose, or most pentoses

77
Q

What is ATP?

A

Adenosine Tri-phosphate (energy carrier)

78
Q

T/F: In fermentation there is a net production of 2 ATP molecules and they are used to regenerate bacteria itself

A

True

79
Q

________ ethanol yield is ___% based on the weight of ________.

A

Theoretical
51.1%
Glucose

80
Q

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

A

86%
ATP
theoretical
inhibition

81
Q

___ - ___% of ethanol is toxic to yeast depending on the strain. ___% ethanol totally inhibitory.

A

8-18%
11%

82
Q

T/F: More resistant yeasts have shorter, unsaturated fatty acids and can make more when exposed to ethanol.

A

False: resistant yeasts gave LONGER unsaturated fatty acids

83
Q

T/F: The problem of osmotic pressure is more prevelant in a CSTR.

A

False: more problematic in a batch reactor (we’re never at steady-state, so high [A] = high release of osmotic pressure)

84
Q

Glycerol, a by-product of ethanol production, accumulates in the largest amount as an ________ metabolite. To avoid large amounts of glycerol production, ________ ________ should be ________.

A

osmoregulatory
osmotic pressure
minimized

85
Q

T/F: Separation of fusel oils and higher alcohols (isobutanol and isoamyl) are more important for potable/pharmaceutical-grade ethanol

A

True

86
Q

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.

A

35
exothermic
18%
20

87
Q

What are the 3 major stages in the conversion of biomass to alcohol?

A
  1. Conversion of biomass to fermentable sugars
  2. Fermentation (conversion of sugars to alcohol)
  3. Recovery (distillation, ethanol storage)
88
Q

T/F: In the distillation phase of alcohol recovery, the distillate contains ~5% water, and is only used to blend with gasoline

A

False: the liquid mixture before distillation contains 5%, and pure alcohol is mixed with gasoline or used for pharmaceutical use

89
Q

What are the two ways in which alcohol is separated from the mixture?

A
  • Use of absorbants (ie. starch, zeolites)
  • Azeotropic distillation with pentane benzene (more expensive)
90
Q

What is stillage?

A

Residue from the distillation. 1L of ethanol produces 10-15L of stillage.

91
Q

T/F: Nitrogen is the largest component of stillage after alcohol distillation from fermented sugar cane juice

A

False: organic matter is the most abundant component

92
Q

What is the main drawback of SHF?

A

Accumulation of glucose inhibits enzyme (cellulase) activity (3g gluc/L = 75% decrease in enz activity)

93
Q

T/F: In SHF, cellulase activity is optimal at 45-50ºC and ethanol production is optimal at 30-37ºC

A

True

94
Q

What is SHF?

A

Separate Hydrolysis Fermentation: hydrolysis of starch to glucose occurs separate of the fermentation process

95
Q

What are the basic steps of SHF?

A

Raw materials > pretreatment > saccharification > Fermentation (add S. cereviceae) > Distillation > Ethanol

96
Q

What is SSF?

A

Simultaneous Saccharification & Fermentation: enzymes and yeast are added to ONE reactor

97
Q

T/F: In SSF, enzymes are manufactured in the same reactor where hydrolysis and fermentation occur

A

False: enzymes manufactured in a separate system

98
Q

What is a major drawback of SSF?

A

Cellulase inhibited by ethanol (30 g/L ethanol decreases activity by 25%)

99
Q

T/F: SHF hydrolysis rates are faster than SSF. It also produces higher ethanol yields, lowers enzyme loading, and lowers capital costs

A

False: opposite process are true

100
Q

What are the basic steps of SSF?

A

Raw materials > pretreatment > saccharification & fermentation (add S. cereviceae and enzyme) > Distillation > Ethanol

101
Q

What is SSCF?

A

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

102
Q

What is CBP?

A

Consolidated bioprocessing: enzyme production and fermentation occurs in the same reactor using recombinant microbes.

103
Q

What is a major drawback currently of CBP?

A

Gene modification = poor growth, low ethanol, low ethanol tolerance, lactic/acetic acid, byproducts

104
Q

T/F: CBP lowers capital costs

A

True

CHEE 342 (4 decks)

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