Fermentation of pretreated source

separated organic (SSO) waste for

ethanol production by different

bacteria by

Bekmuradov Valeriy,

Luk Grace and

Luong Robin

Ryerson University

Toronto, Canada

Montreal, Canada 2013

1

Presentation Outline

• Introduction

• Objectives

• Methodology

• Experimental plan

• Results

• References

2

Introduction

• History of the study – waste problem,

energy crisis, pollution?

• Ethanol? Reasons for use?

• Feedstock availability?

• Processing steps:

– Pre-treatment (Thermal Screw Press)

– COSLIF pre-treatment

– Enzymatic hydrolysis

– Fermentation

3

Ethanol use today

• Used extensively in

some areas of world

– Brazil

• leading user

– United States

• ethanol use is still small %

• U.S. is leading producer

– 6,503.6 million gallons

• Most gasoline engines

can run on E10

U.S.A.

Brazil

E.U.

China

Canada

Other

1.6%

Annual Fuel Ethanol Production (2011)

38.3 %

49.6 %

4

More reasons to use ethanol

• Energy security

• Environmental concerns

• Foreign exchange savings

• Socioeconomic issues related to rural

sector

5

However…today

• Agriculture can have a profoundly positive or negative impact on soil and water quality, water and land use, habitat

• Ethanol from agricultural crops (food based biomass) are still expensive ($2.7 per gallon)

• Needs to occupy new land to produce enough amount of ethanol to meet demand (corn production for ethanol compete with food for land needed)

• Feedstock has uneven fluctuation during the year

• Emission of GHG from food based ethanol is high

6

What is next?

One option is…

• Cellulosic ethanol:

– derived from lignocellulosic biomass • structural component

• i.e. wood, corn stover (leaves and stalks), grasses

• Advantages:

– abundant sources

– could reduce greenhouse gas emissions by 85%

• Disadvantages:

– require more processing to get usable glucose

7

Objectives

• Investigate pretreated SSO waste for sugar and ethanol yields by separate hydrolysis and fermentation (SHF) approach

• Study on performance of commercial available enzyme complex - Accellerase 1500

• Evaluation of selected hydrolysate by fermentation with different bacteria - Z. mobilis 8b and S. cerevisiae DA2416

• Propose a low-cost method utilizing waste biomass for ethanol production and other valuable products

8

Methodology

• Feedstock Material: Source Separated Organic (SSO) waste + Construction & Demolition (CD) wood waste

• Aufbereitungs Technology and System (ATS) thermal screw machine: High pressure and high temperature along with screwing makes the SSO to be a fibrous, homogenous, and less odorous material • Sampling Procedure: Method of Jansen et al. 2004 for obtaining a representative sample • Measurement Procedures: NREL, ASTM, and TAPPI

9

Lignocellulosic biomass

• Introducing Lignocellulosic Biomass resource instead of food-based biomass such as corn and rice

• Lignocellulose is one of the most abundant resources on the Earth on negative cost

• Cellulose: Linear, Insoluble biopolymer composed of repeated unions D-glucose units bonded by ß 1-4 linkages

• Can be hydrolysed to glucose by cellulase enzymes from some microorganisms

10

Lignocellulosic biomass

• Hemicellulose: Random, amorphous, branched chains structure composed of pentose, xylose, other sugars, easily hydrolyzed by dilute acid, base, and hemicellulase enzymes

• Lignin: Complex, three-dimensional polymer of polyphenolic compounds in branched chains, non-crystalline and its structure is similar to a gel or foam

11

Major processing steps in biomass

conversion

12

Pretreatment

13

Pretreatment

14

Deconstruction of plants

15

Termochemical route: courtesy of

DOE/NREL

Biomass composition

16

Biomass composition

17

Mass balance of SSO

18

Limitation of Lignocellulosic

biomass

• Presence of Lignin

• Cellulose Crystallinity

• Accessible Surface Area

• Acetyl Content

• Presence of Hemicellulose

• Almost all lignocellulosic biomass materials need pre-treatment. Without pre-treatment the hydrolysis yield can barely exceed 20% of theoretical yield whereas yields after pre-treatment can reach up to 90% (Lynd, 1996).

19

Experimental plan

20

Parameters of interest

• Pretreatment: temperature, pH, pressure

• Enzymatic hydrolysis: enzyme loading, reaction conditions, substrate concentration, substrate particle size, adsorption capacity and cellulose hydrolysis rate constants, sugar yields

• Fermentation parameters:

ethanol yields & concentration.

21

COSLIF pre-treatment steps

22

COSLIF pre-treatment

23

COSLIF pre-treatment

24

Structural difference on avicel as a pure cellulose (A and B),

avicel treated by 77% phosphoric acid (C and D), treated by

83% phosphoric acid (E and F). Similarly, corn stover substrate

(G) before pretreatment and (H) after COSLIF pretreatment with

85% phosphoric acid.

Enzymatic Hydrolysis Results

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Glucose yield after Enzymatic Hydrolysis (37°C for 48 hours, pH=4.8, FPU=30)

COSLIF Std – washing with acetone

COSLIF Mod – washing with ethanol

0

10

20

30

40

50

60

70

80

90

100

COSLIF Std COSLIF Mod

COSLIF Mod

COSLIF Std

Glucose Yield

Yie

ld %

Enzymatic Hydrolysis Results

Glucan digestibility profiles from COSLIF Std (FPU=60, acetone)

and COSLIF Mod (FPU=30, ethanol) pretreated samples

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0

10

20

30

40

50

60

70

80

90

100

0 12 24 36 48 60 72

COSLIF Std

COSLIF Mod

Glu

ca

n d

ige

stib

ility

%

Time (hr)

Fermentation results

using Z.mobilis 8b strain;

using S.cerevisiae strain

27

0

20

40

60

80

100

120

6hr 12hr 24hr 48hr

COSLIF- Z.mob

COSLIF - S.cer

Ethanol Yield

Th

eo

retical e

tha

no

l yie

ld, %

Fermentation results

140 g/L is equivalent to 0.48 g ethanol/ g biomass

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0

20

40

60

80

100

120

140

160

6hr 12hr 24hr 48hr

COSLIF- Z.mob

COSLIF-S.cer

Ethanol Conc.

Eth

an

ol,(g

/L)%

Fermentation results

Ethanol yield comparison

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Theoretical Ethanol Yield from SSO

Total ethanol yield from 1 ton of dry SSO: 171.3 + 93.95 = 265 L

City of Toronto collects approximately 100,000 tons of SSO per year.

Assuming 45% of the dry weight of SSO, 45,000 tons of dried SSO per

year is available in the city of Toronto, from which ~12ML litres of

ethanol can be produced.

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Advantages of biofuel to replace

gasoline

• Cellulosic bio-fuels can displace 8 million barrels of oil per day- equal to all of the oil used by light-duty vehicles today.

• Bio-fuels can be second only to vehicle fuel economy improvements in the amount of oil they save.

• Bio-fuels, vehicle efficiency and smart growth could eliminate virtually all our demand for gasoline.

• Bio-fuels could reduce global warming pollution by 1.7 billion tons per year-23% of total U.S emissions in 2012.

31

Improving efficiency in biofuel

production

• By 2050, demand rises from the current 160 billion gallons to 289 billion gallons.

• To meet all of this with current crops and current cellulosic conversion technologies, it would required over 1.8 billion acres of land.

• Readily, achievable advances in vehicle fuel economy, overall transport efficiency, crop yields and conversion efficiency could reduce the land requirement to just 116 million acres.

32

Future trends

• Ethanol derived from the cellulosic part of plants rather than just the starch, are the most promising fuels for the transportation sector.

• Replacing oil with bio-fuels would allow to reinvest billions of dollars in factories & farms.

• To maximize the benefits from bio-fuels, need to push technology & market to develop quickly.

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References • Lynd, R. L., Elander, R. T., & Wyman, C. E. (1996). Likely features and cost of

mature biomass technology. Appl. Biochem. Biotechnol. 57/58: 741-761.

• McMillan, J. D. (1994). Pretreatment of lignocellulosic biomass. In: Himmel, M. E., Baker, J. O., Overend, R. P., (Eds). Enzymatic conversion of biomass for fuels production. American Chemical Society, Washington, DC, 292-324.

• Mirzajani, M. (2009). “The amenability of pre-treated source separated organic (SSO) waste for ethanol production”. Master’s thesis, Ryerson University, Civil Engineering dept., Toronto, Canada.

• Ehsanipour, M. (2010).“Acid pretreatment and fractionation of source separated organic waste for lignocellulosic sacharification”. Master’s thesis, Ryerson University, Civil Engineering Dept., Toronto, Canada.

• South, S.R., Hogsett, D., & Lynd, L. (1995). Modeling simultaneous saccharification and fermentation of lignocellulose to ethanol in batch and continuous reactors. Enzyme Microb Technol. 17:797-803

• Vartek Ltd. (2005). Vartek ATS Technology Compost Pilot test. Toronto, Ontario, Canada, Vartek Company.

• Wyman, C. E. (1999). Biomass ethanol: Technical progress, opportunities, and commercial challenges. Annu Rev Energy Environ 24: 189-226.

• Zhang, J., Shao, X., Townsend, O.V., & Lynd, L.R. (2009). Simultaneous saccharification of paper sludge to ethanol by Saccharomyces cerevisiae RWB222. Biotechnology and Bioengineering, 104(5), 920-931.

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Thank you

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