Monthly report –September
Modeling of the natural biodegradation system of cell wall components in wheat straw and wood chips.
Status of the project: Final result analysis and project towards completion.
After collecting all the samples after an incubation of 20 week period in soil. All the five batches were grinded in wood lab .The grinded samples were analyzed for the changes in the functional groups and structural chemical changes with the help of following techniques.
GC-MS Pyrolysis- The GS-MS pyrolysis samples were first analysed for the first, second and third ,fourth and fifth samples .The results in fourth and fifth batch was not proper as the difference was more than expected in the hydroxyl and phenolic hydroxyl groups so the analyses was again done for these samples. The control was done earlier for the preliminary results so this was not done this time.
Attached are the results for the GC-MS pyrolysis results which have control and all the five batches.
FTIR: FTIR analysis was done on all the samples where in first baseline correction along with multipoint correction was done, later only baseline correction was done with which the change in the functional groups was observed. Attached are the results for the FTIR analysis.
Estimation of sugars and Lignin in all the batch samples – This was done by the following steps
The protocol followed was given my Dr Manuel.
· The grinded samples from all the batches were first chemically treated with ethanol and benzene using Soxlet mechanism for 12 hours. The ratio of wheat straw and wood chips was 1:1 and the ratio which was taken for ethanol and benzene was 1:2 as solvent.
· After the first step the extractives which are defined as all the proteins, fatty acids, dicarboxylic acids, alkanes, ketones, aldehydes other than cellulose, hemicelluloses and lignin are removed.
· The samples are collected and dried and stored.
· Two step hydrolysis is done using 3ml Sulphuric acid and later 75ml of water is added.
· This is filtered and the filtrate is tested for insoluble lignin and the liquid is tested for Sugars (cellulose and hemicelluloses).
Result: The analysis of sugars using IC is pending as the IC is out of order.
Predicted results: Based on the compositional analysis of all the three components; Cellulose, hemicelluloses and lignin a mathematical model is to be constructed which would give us an equation for determining the right proportion of cellulose and hemicelluloses which helps in lignin degradation .This would be with respect to time.
Solid state NMR: The solid state NMR is used to analyze the quantitative proportion of the lignin, cellulose and hemicelluloses with respect to mass conservation. i e based on the NMR results we can predict the structural chemical changes with respect to carbon changes.
Greg Helms Director of NMR helped me in the analysis. As the samples had soil the results had lot of noise and were difficult to predict. Later we tried to use the samples which were free of extractives assuming that 12 hour soxlet treatment would have filtered soil apart from other components.
As the results were still out of phase and difficult to compare all the sample spectra. We tried to put a standard TSP. (10.4 Mille grams in each 7.5 mm rotar ) along with sample. And these spectra showed sharp peaks with standard peak helped in comparing the results. The analysis is still going on. In the mean time the spectra obtained from the original samples which had soil and extractives were graphically constructed again in way where the standard was fixed in the spectra and then observed. Attached are the NMR spectra for those samples. Where in the black and red are the fifth and fourth samples showed changes.
Based on the present NMR, GC-MS PYROLYSIS and FTIR results there is a pattern observed in the 4th and 5th batch samples. All show the same specific changes.
Work to be done this week:
The modeling based on the composition of the sugars and lignin is to be done.
NMR results have to be completed and analyzed.
Based on which the preparation for the ASABE conference has to done.