bioconversion process of source separated organic … of the... · fermentation of pretreated...

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

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Pretreatment

13

Pretreatment

14

Deconstruction of plants

15

Termochemical route: courtesy of

DOE/NREL

Biomass composition

16

Biomass composition

17

Mass balance of SSO

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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

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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

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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.

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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.

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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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