• Mechanical
    Pretreatment of Biomass
    Bioprocess Development

Background

Lignocellulosic Biomass

Lignocellulosic biomass is defined as a plant, or plant-derived, material that is mostly composed of cellulose, hemicellulose, and lignin. Lignocellulosic feedstocks are highly abundant, covering many biomass types including grasses, wood, energy crops (e.g. Miscanthus and coppices), agricultural residues (e.g. straws and corn stover), and municipal wastes.

Lignocellulosic feedstocks are highly abundant and can often be sourced sustainably, at low cost, without leading to land-use conflicts. As a result, there is currently great interest in obtaining chemicals, fuels, and biomaterials from such biomass.



Biomass Hydrolysis

A major pathway by which many lignocellulosic feedstocks are processed is known as hydrolysis, where sugars are released from the lignocellulosic polysaccharides (i.e. cellulose and hemicellulose).

However, the hydrolysis of lignocellulosic polysaccharides is not easy and is influenced by the complex inter-associations between hemicellulose and cellulose and between these polysaccharides and lignin in the lignocellulosic matrix. In particular, the crystalline nature of much cellulose and the existence of a physical barrier of lignin surrounding the cellulose fibres are said to be major contributors to the recalcitrance of cellulose.

The mechanism of hydrolysis is further complicated by the fact that different process intensities are required for the hydrolysis of cellulose versus hemicellulose. The more intense conditions required for cellulose hydrolysis may degrade the sugars hydrolysed from hemicellulose (to products such as furfural and formic acid).

For this reason, most hydrolysis technologies employ pre-treatment processes that aim to break apart the matrix (and in particular the associations between lignin and cellulose), reduce cellulose crystallinty, and hydrolyse hemicelluloses, hence separating the hydrolysate from cellulose which can then undergo more severe/targeted treatment.

Get more info...Biomass Hydrolysis




Need for Pretreatment

For this reason, most hydrolysis technologies employ pre-treatment processes that aim to break apart the matrix (and in particular the associations between lignin and cellulose), reduce cellulose crystallinty, and hydrolyse hemicelluloses, hence separating the hydrolysate from cellulose which can then undergo more severe/targeted treatment.

Get more info...Pretreatment Homepage





Mechanical Pretreatment of Biomass

Mechanical pretreatment is used to reduce the particle size for ease of handling and increased surface/volume ratio. This can be done by chipping, milling, or grinding.

It is generally the case that the smaller the particle size, the higher the efficiency of the process. However, excessive reduction in particle size may cause process issues (e.g. viscosity, high water holding, filter clogging etc.).

Depending on the pretreatment conditions, and on the particle-size reduction tools used in the process, the pretreatment process may also cause the biomass to shear and reduce the degree of polymerization, which in turn increases the available accessible area to chemicals, enzymes and microbes.


Other Types of Biomass Pretreament

Steam Pretreatment

Steam pretreatment uses high-pressure steam at elevated temperatures. In steam-explosion pretreatment this is followed by rapid decompression which physically disrupts the biomass structure.

Get more info...Steam Pretreatment






Hydrothermal Pretreatment

Hydrothermal pretreatment, also know as Liquid Hot Water (LHW) pretreatment, does not involve the use of any chemicals but operates at elevated temperatures and pressures

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Acid Pretreatment

This pretreatment involves treating the biomass with a dilute solution of a strong acid at elevated temperatures. A primary target is the hydrolysis of hemicellulose into monomeric sugars.

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Alkali Pretreatment

Alkali pretreatment uses chemicals (e.g. sodium hydroxide, potassium hydroxide, calcium hydroxide) to disrupt the complex structure of lignocellulosic biomass with lignin removal a primary target.

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Organosolv Pretreatment

Organosolv pretreatment fractionates biomass into its three major components (cellulose, hemicellulose, and lignin), with obtaining a lignin of a high-purity and quality being a particular target.

Get more info...Organosolv Pretreatment






Other Pretreatments

This page covers some other pretreatments: ionic liquids pretreatment, hydrogen-peroxide pretreatment, ultrasonic pretreatment, microwave pretreatment, fungal pretreatment, and bacterial pretreatment.

Get more info...Other Pretreatments






Pretreatment Homepage

Click here to read more about the important factors to consider when designing a biomass pretreatment process and to read about how we undertake our pretreatment development projects with our clients.

Get more info...Pretreatment Homepage






 



How our Bioprocess Development Services Work

Our Bioprocess Development Services can work on the evaluation and optimisation of a particular node in the biomass processing technology or can involve the development of a bespoke vertically-integrated technology for your chosen feedstock and/or product. Click here to see how our Bioprocess Development Services work and how we devise and undertake a project.

With regards to the pretreatment of biomass, the Celignis Bioprocess team members with the most experience in undertaking such projects are listed below. Feel free to contact them to discuss potential projects.

Lalitha Gottumukkala

Founder of Celignis Bioprocess, CIO of Celignis

PhD

Has a deep understanding of all biological and chemical aspects of bioproceses. Has developed Celignis into a renowned provider of bioprocess development services to a global network of clients.

Oscar Bedzo

Bioprocess Project Manager & Technoeconomic Analysis Lead

PhD

A dynamic, purpose-driven chemical engineer with expertise in bioprocess development, process design, simulation and techno-economic analysis over several years in the bioeconomy sector.

Dan Hayes

Celignis CEO And Founder

PhD (Analytical Chemistry)

Dreamer and achiever. Took Celignis from a concept in a research project to being the bioeconomy's premier provider of analytical and bioprocessing expertise.





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