Investigating and Modeling Natural Biodegradation System in Soil;

Application for Designing an Efficient Biological Pretreatment Technology for Biofuel

Production.

Mythreyi Chandoor, Deepak Singh and Shulin Chen

Bioprocessing and Bioproduct Engineering Laboratory, Department of Biological Systems

Engineering Washington State University .

outline

•Aim and importance of the project• Background – Hypothesis of the project• Experimental:

MicrobiologyChemical analysis of lignocellulose degradation in soil.

• ModelingLignocellulose degradation in soilApplication

• Acknowledgements

Aim and importance of the project

•Demand for an Alternative Fuel – The U.S. ethanol consumption is forecast to increase from 5.6 billion gallons last year to 13.5 billion gallons in 2012, (Thomson Reuters, 2009). • What are the challenges ? One of the challenges lies in the deconstruction of lignin part of the biomass to release sugars.

Need for novel pretreatment Technology !!

•Demand for an Alternative Fuel – The U.S. ethanol consumption is forecast to increase from 5.6 billion gallons last year to 13.5 billion gallons in 2012, (Thomson Reuters, 2009). • What are the challenges ? One of the challenges lies in the deconstruction of lignin part of the biomass to release sugars.

Need for novel pretreatment Technology !!

Delignification, repolymerization

Humus formation

Proteins

in soil

Lignocellulosic system in soil

•To understand the biodegradation of lignocellulose in soil

• To model the biodegradation of lignocellulose in soil

Design the pretreatment system

Aim of the Project

Methodology

Scanning Electron Microscopy (SEM)

Scanning Electron Microscopy (SEM)

Aromatic carbons attached to methoxy groups in syringol unit

Guiacyl moities

C2,C3,C5 of cellulose

C4 of amorphous and crystalline

cellulosePhenolmethoxyl of

coniferyl and sinapyl moities

4 weeks 8 weeks

12 weeks16 weeks

Solid State NMR Analysis

Solid State NMR Analysis

The Oxidation of syringyl and guaicyl units of lignin will give rise to syringol and guaicol units.

Quantitatively , syringyl and guaicyl units have decreased where as the syringol and guaicol amounts have increased which shows that there is change in

the chemical nature of lignin structure

Solid State NMR Analysis

Batch samples for every four weeks

% C

once

ntr

atio

n o

f th

e to

tal c

omp

oun

d

Py-GC/MS Analysis

Py-GC/MS Analysis

The increase in the lignin content is attributed to the kind of subunits taken into consideration ; Syringol ,Guaicol , Ethanone and others were considered which are formed as a result of oxidation or modification of lignin.

Cellulose and Hemicellulose are proportionately decreasing while the lignin concentration is stable

and increased after a period of 12 weeks

Py-GC/MS Analysis

TG Analysis

min0 5 10 15 200 250 300 350 40 45 50 55

Soil Sample S5

Soil sample S4,

After 20 weeks

After 16 weeks

After 12 weeks

After 8 weeks

After 4 weeks Cellulose and hemicellulose

Lignin

Modeling General Equation for the Soil Degradation system

[S]+[X]+O2 + H2O [P] + [S1] + CO2 +[X]Soil

pH

where in S = s1+ s2 + s3 .X = x1 +x2 +x3 .P = products ( glucose and other residual sugars ).S1 = modif ied lignin .

( s1 =cellulose , s2= hemicellulose, s3= lignin )

(Maximum microbial growth on the biomass respectively )

Water balance equation :

dm H2O /dt = dmbio H20/dt + dm H2O intake / dt - dmexhaust H2O/dt

mH20 = mass of H20 in soil mbio

H2O = mass of H2O evolution taking place as a result of the degradation dm H2O

intake = water intake via intake airdmexhaust H2O = Water outlet Via exhaust air here ,dmbio H20/dt = 0

Therefore , dm H2O /dt = dm H2O intake / dt - dmexhaust H2O/dt

(Input = output +accumulation - generation)

d(S1) / d(t) = -Vb1*S1*X1/(Ks1+S1) #Cellulose BalanceS1(0) = 0.71 # weight in gm/gm  

d(S2) / d(t) = -Vb2*S2*X2/(Ks2+S2) #Hemicellulose BalanceS2(0) = 0.48 #  

d(S3) / d(t) = -Vb3*S3*X3/(Ks3+S3) #Lignin BalanceS3(0) = 0.28 #  

Modeling

Considering the values as follows ;µmax1=0.08 ∆ 1=0.001µmax2=0.05 ∆ 2=0.001μmax3=0.03 ∆ 3=0.001

We derived an relation using polymath which defines the degradation pattern in the soil system.  

Modeling

Time (in hours )

Init

ial S

ubst

rate

co n

cent

r ati

on in

gm

/ gm

Application of the model

•The model developed is a relation drawn between the total initial concentrations of the cellulose, hemicellulose and lignin defined in a specific proportion at any point of time .

•Further ,the model would correlate the various factors involved parallel to the degradation rates of each component respectively.

•The model developed is a relation drawn between the total initial concentrations of the cellulose, hemicellulose and lignin defined in a specific proportion at any point of time .

•Further ,the model would correlate the various factors involved parallel to the degradation rates of each component respectively.

Conclusion

The determination of the exact relation between these factors would be helpful in developing a model which would predict the specific ratio of cellulose, hemicellulose and lignin apart from other factors involved such as pH , temperature and other organic compounds.

Thus providing a suitable mechanism for the pretreatment technology !!

The determination of the exact relation between these factors would be helpful in developing a model which would predict the specific ratio of cellulose, hemicellulose and lignin apart from other factors involved such as pH , temperature and other organic compounds.

Thus providing a suitable mechanism for the pretreatment technology !!

I would like to thank

•Dr. Ann Kennedy USDA-ARS Soil Scientist/ Adj. Prof. Crop and Soil Sciences,WSU.

•Dr. Greg Helms, NMR Center Director ,WSU.•Dr. Manuel Garcia-Perez. Assistant Professor / Scientist. Biological Systems Engineering ,WSU.•Dr. Bill , Assistant manager ,NMR Center,WSU.

And my Advisor …•Dr. Shulin Chen, Professor/Scientist. Department of Biological Systems Engineering,WSU .

Acknowledgements

And

My Team …

Thank you …

Any Questions ?