Fermentation of pretreated source separated organic (SSO) waste for ethanol production by different bacteria

Save this PDF as:

Size: px
Start display at page:

Download "Fermentation of pretreated source separated organic (SSO) waste for ethanol production by different bacteria"


1 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

2 Presentation Outline Introduction Objectives Methodology Experimental plan Results References 2

3 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

4 Ethanol use today Used extensively in some areas of world Brazil leading user 1.6% United States ethanol use is still small % U.S. is leading producer U.S.A. 6,503.6 million gallons Most gasoline engines can run on E % 49.6 % Brazil E.U. China Canada Other Annual Fuel Ethanol Production (2011) 4

5 More reasons to use ethanol Energy security Environmental concerns Foreign exchange savings Socioeconomic issues related to rural sector 5

6 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

7 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

8 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

9 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 for obtaining a representative sample Measurement Procedures: NREL, ASTM, and TAPPI 9

10 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

11 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

12 Major processing steps in biomass conversion 12

13 Pretreatment 13

14 Pretreatment 14

15 Deconstruction of plants Termochemical route: courtesy of DOE/NREL 15

16 Biomass composition 16

17 Biomass composition 17

18 Mass balance of SSO 18

19 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 pretreatment can reach up to 90% (Lynd, 1996). 19

20 Experimental plan 20

21 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

22 COSLIF pre-treatment steps 22

23 COSLIF pre-treatment 23

24 COSLIF pre-treatment 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. 24

25 Yield % Enzymatic Hydrolysis Results COSLIF Std Glucose Yield COSLIF Mod COSLIF Mod COSLIF Std 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 25

26 Glucan digestibility % Enzymatic Hydrolysis Results Time (hr) COSLIF Std COSLIF Mod Glucan digestibility profiles from COSLIF Std (FPU=60, acetone) and COSLIF Mod (FPU=30, ethanol) pretreated samples 26

27 Theoretical ethanol yield, % Fermentation results Ethanol Yield COSLIF- Z.mob COSLIF - S.cer hr 12hr 24hr 48hr using Z.mobilis 8b strain; using S.cerevisiae strain 27

28 Ethanol,(g/L)% Fermentation results Ethanol Conc COSLIF- Z.mob COSLIF-S.cer 0 6hr 12hr 24hr 48hr 140 g/l is equivalent to 0.48 g ethanol/ g biomass 28

29 Fermentation results Ethanol yield comparison 29

30 Theoretical Ethanol Yield from SSO Total ethanol yield from 1 ton of dry SSO: = 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. 30

31 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

32 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

33 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. 33

34 References Lynd, R. L., Elander, R. T., & Wyman, C. E. (1996). Likely features and cost of mature biomass technology. Appl. Biochem. Biotechnol. 57/58: 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, 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: 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: 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),

35 Thank you 35