• Feedstocks Analysed at Celignis
    Pretreated Biomass

Background on Pretreated Biomass

Lignocellulosic biomass can be highly recalcitrant to conversion to advanced biofuels. It is therefore very important that pretreatments are carried out prior to the main conversion process.

Types of pretreatment include: particle size reduction; steam explosion; ammonia fibre explosion; liquid hot water treatment; dilute acids; alkalis; wet oxidation; organosolv; formic acid; hydrogen peroxide; supercritical CO2; ionic liquids; ozonolysis; and biological pretreatments.

Our Recommendations for Evaluating Pre-Treatment Processes
We have a lot of experience in analysing many products (both liquid and solid) from biomass pre-treatment processes. These samples have covered a wide variety of starting feedstocks and pre-treatment processes and conditions. Below we recommend a set of Celignis analysis packages for getting the most detailed data about the whole conversion process:

(1) The Starting Feedstock
We recommend that analysis package P10 - Sugars, Lignin, Extractives, and Ash is used as this will fully remove the extractives prior to the hydrolysis stage meaning that you can be confident that the sugars reported in this package come from lignocellulose.

We would also recommend analysis package P12 - Sugars in Solvent Extract as this will report the amount of water-soluble carbohydrates in the sample. It is likely that water-soluble carbohydrates will be present in the liquid output of many pre-treatment processes and, if their concentrations are not known, it may be incorrectly inferred that such sugars present in the liquid must come from lignocellulose. However, if the water-soluble carbohydrate composition is known then these values can be substracted from the amounts of sugars in the pre-treatment liquid to determine the amount of true lignocellulosic sugars that are present.

Similarly, if you expect that there will be some starch in your sample then we also recommend that analysis package P14 - Starch Content is also undertaken as starch may also be removed and hydrolysed in many pre-treatment processes.

Additionally, if you are interested in the uronic acid composition of the biomass then we recommend analysis package P15 - Uronic Acids is also undertaken.


(2) The Liquid Product from Pre-treatment
For the most detailed results, we would recommend that the liquid output is analysed using analysis packages P13 - Sugars and Oligosaccharides in Solution, P22 - Organic Acids and Furans, and P15 - Uronic Acids. However, if uronic acids are expected to be very low in your original biomass sample then that analysis package may not need to be undertaken.


(3) The Solid Residue from Pre-treatment
As it is likely that most of the extractives will have been removed in the pre-treatment, it may not be necessary to remove or characterise these. Instead, we recommend that analysis package P9 - Lignocelullosic Sugars and Lignin is undertaken to determine the lignocellulosic composition of the residue. We would also recommend that analysis package P3 - Ash Content is also undertaken to see whether the pre-treatment process significantly changes the ash content of the sample. Also, if the fate of the uronic acids is of interest then analysis package P15 - Uronic Acids could be undertaken.

Analysis of Pretreated Biomass at Celignis



Celignis Analytical can determine the following properties of Pretreated Biomass samples:



Lignocellulosic Properties of Pretreated Biomass

Cellulose Content of Pretreated Biomass

Pre-treatment can greatly change the composition of biomass, with the effect dependent on the process used. For example, dilute acid hydrolysis pre-treatments will hydrolyse a large portion of the hemicellulose fraction, leading to an increased relative cellulose and lignin content in the residual solid biomass.

Click here to see the Celignis Analysis Packages that determine Cellulose Content

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Hemicellulose Content of Pretreated Biomass

Many pre-treatments can result in the hydrolysis of part or all of the hemicellulose fraction, meaning that the concentration of hemicellulose in the residual solid biomass can be decreased.

Click here to see the Celignis Analysis Packages that determine Hemicellulose Content

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Lignin Content of Pretreated Biomass

Lignin is a major contributor to the recalcitrance of lignocellulosic biomass to enzymatic hydrolysis. Some organosolv pre-treatments target the removal of the lignin fraction, leaving a relativelty pure cellulose fraction that is more amenable to hydrolysis by enzymes.

Click here to see the Celignis Analysis Packages that determine Lignin Content

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Starch Content of Pretreated Biomass

Different pre-treatment processes can have differing effects on the starch contained within biomass. For example, a dilute acid process is likely to remove starch, along with some hemicellulose sugars.

Click here to see the Celignis Analysis Packages that determine Starch Content

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Uronic Acid Content of Pretreated Biomass

Depending on the severity of the pre-treatment conditions, the uronic acids that were present in the original biomass may either have been removed (e.g. hydrolysed) or retained within the residual solid biomass. We can determine uronic acid contents of liquid output streams from pre-treatment processes as well as the uronic acid content of biomass and solid process residues.

Click here to see the Celignis Analysis Packages that determine Uronic Acid Content

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Enzymatic Hydrolysis of Pretreated Biomass

We can undertake tests involving the enzymatic hydrolysis of Pretreated Biomass. In these experiments we can either use a commercial enzyme mix or you can supply your own enzymes. We also offer analysis packages that compare the enzymatic hydrolysis of a pre-treated sample with that of the native original material.

Click here to see the Celignis Analysis Packages that determine Enzymatic Hydrolysis

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Bioenergy Properties of Pretreated Biomass

Ash Content of Pretreated Biomass

The effect of pre-treatment on the ash content and composition will be dependent on the process used.

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Heating (Calorific) Value of Pretreated Biomass

The effect of the pre-treatment process on the heating value of biomass will depend on what biomass components (e.g. extractives, cellulose, hemicellulose, lignin, ash) are reduced and which ones are proportionately increased as a result of the process.

Click here to see the Celignis Analysis Packages that determine Heating (Calorific) Value

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Ash Melting Behaviour of Pretreated Biomass

Ash melting, also known as ash fusion and ash softening, can lead to slagging, fouling and corrosion in boilers which may reduce conversion efficiency. We can determine the ash melting behaviour of Pretreated Biomass using our Carbolite CAF G5 BIO ash melting furnace. It can record the following temperatures:

Ash Shrinkage Starting Temperature (SST) - This occurs when the area of the test piece of Pretreated Biomass ash falls below 95% of the original test piece area.

Ash Deformation Temperature (DT) - The temperature at which the first signs of rounding of the edges of the test piece occurs due to melting.

Ash Hemisphere Temperature (HT) - When the test piece of Pretreated Biomass ash forms a hemisphere (i.e. the height becomes equal to half the base diameter).

Ash Flow Temperature (FT) - The temperature at which the Pretreated Biomass ash is spread out over the supporting tile in a layer, the height of which is half of the test piece at the hemisphere temperature.



Click here to see the Celignis Analysis Packages that determine Ash Melting Behaviour

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Major and Minor Elements in Pretreated Biomass

Examples of major elements that may be present in Pretreated Biomass include potassium and sodium which are present in biomass ash in the forms of oxides. These can lead to fouling, ash deposition in the convective section of the boiler. Alkali chlorides can also lead to slagging, the fusion and sintering of ash particles which can lead to deposits on boiler tubes and walls.

We can also determine the levels of 13 different minor elements (such as arsenic, copper, and zinc) that may be present in Pretreated Biomass.

Click here to see the Celignis Analysis Packages that determine Major and Minor Elements

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Analysis of Pretreated Biomass for Anaerobic Digestion



Biomethane potential (BMP) of Pretreated Biomass

Pre-treatment can be a very effective technique to reduce the recalcitrance of lignocellulosic biomass to degradation in anaerobic digestion processes. There have been a large number of studies covering a wide variety of pre-treatments and feedstocks. Many of these have shown a significant increase in the biochemical methane potential (BMP) associated with the pre-treatment.

However, the increase in BMP often varies greatly according to the conditions and type of pre-treatment employed. For that reason we recommend that the biochemical methane potential test is undertaken in order to evaluate the effectiveness of any given pre-treatment process regarding improving potential biogas yields in anaerobic digestion.

Click here to see the Celignis Analysis Packages that determine BMP

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Physical Properties of Pretreated Biomass



Bulk Density of Pretreated Biomass

At Celignis we can determine the bulk density of biomass samples, including Pretreated Biomass, according to ISO standard 17828 (2015). This method requires the biomass to be in an appropriate form (chips or powder) for density determination.



Click here to see the Celignis Analysis Packages that determine Bulk Density

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Particle Size of Pretreated Biomass

Pre-treatment can be a very effective technique to reduce the recalcitrance of lignocellulosic biomass to degradation in anaerobic digestion processes. There have been a large number of studies covering a wide variety of pre-treatments and feedstocks. Many of these have shown a significant increase in the biochemical methane potential (BMP) associated with the pre-treatment.

However, the increase in BMP often varies greatly according to the conditions and type of pre-treatment employed. For that reason we recommend that the biochemical methane potential test is undertaken in order to evaluate the effectiveness of any given pre-treatment process regarding improving potential biogas yields in anaerobic digestion.

Click here to see the Celignis Analysis Packages that determine Particle Size

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Publications on Pretreated Biomass By The Celignis Team

V.P. Zambare, Lew P. Christopher (2012) Optimization of enzymatic hydrolysis of corn stover for improved ethanol production, Energy Exploration & Exploitation 30(2): 193-205

Link

Response surface methodology (RSM) was used to optimize the enzymatic hydrolysis of corn stover (CS), an abundant agricultural residue in the USA. A five-level, three-variable central composite design (CCD) was employed in a total of 20 experiments to model and evaluate the impact of pH (4.16.0), solids loadings (6.623.4%), and enzyme loadings (6.6?23.4 FPU g?1 DM) on glucose yield from thermo-mechanically extruded CS. The extruded CS was first hydrolyzed with the crude cellulase of Penicillium pinophilum ATCC 200401 and then fermented to ethanol with Saccharomyces cerevisiae ATCC 24860. Although all three variables had a significant impact, the enzyme loadings proved the most significant parameter for maximizing the glucose yield. A partial cubic equation could accurately model the response surface of enzymatic hydrolysis as the analysis of variance (ANOVA) showed a coefficient of determination (R2 ) of 0.82. At the optimal conditions of pH of 4.5, solids loadings of 10% and enzyme loadings of 20 FPU g?1 DM, the enzymatic hydrolysis of pretreated CS produced a glucose yield of 57.6% of the glucose maximum yield which was an increase of 10.4% over the non-optimized controls at zero-level central points. The predicted results based on the RSM regression model were in good agreement with the actual experimental values. The model can present a rapid means for estimating lignocellulose conversion yields within the selected ranges.

Vasudeo Zambare, Archana Zambare, Debmalya Barh, Lew Christopher (2012) Optimization of enzymatic hydrolysis of prairie cordgrass for improved ethanol production, Journal of Renewable and Sustainable Energy 4(3): 1-8

Link

Prairie cordgrass (PCG), Spartina pectinata, is considered an energy crop with potential for bioethanol production in North America. The focus of this study was to optimize enzymatic hydrolysis of PCG at higher solids loadings using a thermostable cellulase of a mutant Penicillium pinophilum ATCC 200401. A three variable, five-level central composite design of response surface methodology (RSM) was employed in a total of 20 experiments to model and evaluate the impact of pH (4.16.0), solids loadings (6.6%23.4%), and enzyme loadings (6.623.4 FPU/g dry matter, DM) on glucose yield from a thermo-mechanically extruded PCG. The extruded PCG was first hydrolyzed with the crude P. pinophilum cellulase and then fermented to ethanol with Saccharomyces cerevisiae ATCC 24860. Although all three variables had a significant impact, the enzyme loadings proved the most significant parameter for maximizing the glucose yield. A partial cubic equation could accurately model the response surface of enzymatic hydrolysis as the analysis of variance showed a coefficient of determination (R2) of 0.89. At the optimal conditions of pH of 4.5, solids loadings of 10% and enzyme loadings of 20 FPU/g DM, the enzymatic hydrolysis of pretreated PCG produced a glucose yield of 76.1% from the maximum yield which represents an increase of 15% over the non-optimized controls at the zero-level central points. The predicted results based on the RSM regression model were in good agreement with the actual experimental values. The model can present a rapid means for estimating lignocellulose conversion yields within the selected ranges. Furthermore, statistical optimization of solids and enzyme loadings of enzymatic hydrolysis of biomass may have important implications for reduced capital and operating costs of ethanol production.





Examples of Other Feedstocks Analysed at Celignis



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