Hydrolysis
| Technology | |
| |
| Technology details | |
| Name: | Hydrolysis |
| Category: | Pre-processing |
| Feedstock: | Lignocellulosic biomass |
| Product: | Sugars and organic acids |
Hydrolysis (/haɪˈdrɒlɪsɪs/; from Ancient Greek hydro- 'water', and lysis 'to unbind') is a chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions that use water as the reagent.[1] In lignocellulosic biomass, the cellulose and hemicellulose breaks down into individual sugars. Hemicellulose is easier to hydrolyse than cellulose.[2] The result of hydrolysing hemicellulose and cellulose are sugars (glucose, mannose, galactose, (C6) and xylose, arabinose (C5)) and organic acids (formic acid and acetic acid).[3]
Feedstock
Origin and composition
Hydrolysis can be performed as a pretreatment on any biowaste with a high lignocellulose content. Lignocellulose is typically the nonedible part of a plant, composed of a complex of cellulose, hemi-cellulose and lignin. Suitable feedstocks include grasses, straw, leaves, stems, shells, manure, paper waste, and others. The ratio between cellulose, hemi-cellulose and lignin varies wildly depending on the specific feedstock.[4]
Cellulose
Explain structure of cellulose
Hemi-cellulose
Explain structure of hemi-cellulose
Lignin
Explain structure of Lignin
Process and technologies
Chemical hydrolysis
Chemical pretreatments have been used extensively for removal of lignin surrounding cellulose and for destroying its crystalline structure. Even though chemical pretreatments are usually effective, they have disadvantages which should not be ignored [10]. These include use of specialized corrosion resistant equipment, need for extensive washing, and disposal of chemical wastes. Various chemical methods are discussed under several headings, namely, alkalis, acids, gases, oxidizing agents, cellulose solvents, extraction, and swelling agents.
Acid hydrolysis
Acid hydrolysis is a hydrolysis process in which a protic acid is used to catalyze the hydrolysis reaction. Acids are used mainly for hydrolysis of cellulose [10]. A strong acid, such as formic, hydrochloric, nitric, phosphoric, or sulphuric acid can be used in concentrated or diluted form. Concentrated acid (10-30 %) can penetrate the lignin structure and break down the cellulose and hemicellulose to individual sugars at low temperature and with high yield. Downsides are the high acid consumption and high corrosion potential. These downsides are circumvented with the use of diluted acid (2-5 %). However, in the latter case, higher temperature is required, which can lead to side product formation such as furfural and 5-hydroxymethyl-furfural.[4]
Acid hydrolysis can be further improved by the addition of salts, such as metal salts or suphite salts. Metals such as aluminium, calcium, copper, iron and zincnc can be used to increase the sugar yield [6]. Similar to sulphite pulping, sulphites can be added to aid in lignin removal. .
Sulfuric acid
Elaborate more the reactions conditions and give some examples from literature.
Hydrochloric acid
Elaborate more the reactions conditions and give some examples from literature.
Phosphoric acid
Elaborate more the reactions conditions and give some examples from literature.
Alkaline hydrolysis
Alkaline hydrolysis refers to hydrolysis reactions using hydroxide, commonly from sodium hydroxide or calcium hydroxide. The hydroxide breaks down the lignin bonds to make the cellulose more accessible. The reaction proceeds at lower temperature and pressure and residual alkali can be recycled. However, the pretreatment does result in irrecoverable salts in the product.[5]
Sodium hydroxide
Dilute sodium hydroxide (NaOH) treatment of lignocellulosic material causes swelling, leading to an increase in internal surface area, decrease in the degree of polymerization, decrease in crystallinity, separation of structural linkages between lignin and carbohydrates, and disruption of the lignin structure [10].
Elaborate more the reactions conditions and give some examples from literature.
Ammonia
Liquid or gaseous ammonia acts as a strong swelling agent for cellulose [1].
Elaborate more the reactions conditions and give some examples from literature.
Ammonium sulfite
Ammonium sulfite is used mainly in a conventional pulping process.
Elaborate more the reactions conditions and give some examples from literature.
Solvent
Solvents can be added to improve the hydrolysis process. This is similar to organosolv pulping, but without the delignification as goal.[6]
Organosolv
In an organosolv hydrolysis organic solvents are added to the process, usually performed at high temperatures (100-250 °C). This can be combined with a catalyst such as HCl or H2SO4.[6] For example, in acid-acetone pre-treatment biowaste is treated with an acid such as phophoric acid and then mixed with pre-cooled acetone.[7]
Ionic Liquids
Ionic liquids are solvents that can be used for biomass pretreatment, fractionation, and dissolution. During ionic liquid pretreatment, a cellulose-rich fraction can be generated through the degradation and removal of a large portion of lignin and hemicellulose [8]
Subcritical water
Subcritical water hydrolysis (SWH) can also be called hydrothermal liquefaction, hydrothermolysis, or aquathermolysis. The technique uses water at high temperatures and pressures to keep it in a liquid form. SWH can reduce reaction time and thereby degradation product formation, generates less waste water and lower corrosion requirements.[9]
Enzymatic hydrolysis
Enzymatic hydrolysis is a catalytic decomposition of a chemical compound by reaction with water, such as the conversion of lignocellulosic materials, by the addition of specific enzymes.
However, the hydrolysis of native lignocellulosic material is slow and is primarily governed by their structural features, since:
1. cellulose present in biomass possesses highly resistant crystalline structure;
2. lignin surrounding the cellulose forms a physical barrier;
3. The sites available for enzymatic attack are limited.
The cellulose present in lignocellulosic materials is composed of crystalline and amorphous components. The amorphous component is more susceptible to enzymatic attack than the crystalline component. The presence of lignin forms a physical barrier for enzymatic attack; therefore, treatments causing disruption of the lignin seal will increase the accessibility of cellulose to enzyme molecules and eventually its hydrolysis rate. The limitation of available sites for enzymatic attack stems from the fact that the average size of the capillaries in biomass is too small to allow the entry of large enzyme molecules; and thus, enzymatic attack is confined to the external surface [10].
Pretreatment, therefore, is an essential prerequisite to enhance the susceptibility of lignocellulosic materilas to enzyme action. An ideal pretreatment would accomplish reduction in lignin content, concommitant with a reduction in crystallinity, and an increase in surface area. The variety of pretreatments can be classified into physical, chemical, and biological depending on the mode of their action [10].
Biological hydrolysis
Lignin degradation can also occur through the action of lignin degrading enzymes secreted by microorganisms (e.g. fungi).
Product
Hydrolysis is generally performed on cellulose and hemi-cellulose, which results in different sugars: glucose, mannose, and galactose as C6 sugars, and xylose and arabinose asC5 sugars. Next to these, organic acids are often formed in formic acid and acetic acid.
Post-treatment
Currently no post-treatment has been identified.
Technology providers
| Company name | Country | Technology category | Technology name | TRL | Capacity [kg/h] | Catalyst loading [wt %] | pH | Pressure [bar] | Reactor | Residence time [h] | Temperature [°C] | Feedstock: Food waste | Feedstock: Garden & park waste |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Company 1 | [Country HQ location] | [Technology category (if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● | ||||||
| Company 2 | [Country HQ location] | [(if different sub-categories are defined this has to be specified here, the available categories can be found on each technology page under the chapter Process and technologies)] | [Technology name (the "branded name" or the usual naming from company side)] | [4-9] | [numeric value] | ● | ● |
NextChem
Valmet Oyj
| General information | |||
| Company: | Valmet Oyj |
| |
| Country: | Finland | ||
| Contact: | |||
| Webpage: | https://www.valmet.com/ | ||
| Technology and process details | |||
| Technology name: | BioTrac | Technology category: | Pre-processing (Chemical processes and technologies) |
| TRL: | 9 | Capacity: | biomass feed up to 800 tonne/day kg·h-1 |
| Agitator: | Atmosphere: | ||
| Catalyst: | Acidic conditions | Controlled parameters: | |
| Temperature: | High °C | Catalyst: | Acidic conditions |
| Processable volume: | L | Reactor: | Horizontal tube reactor |
| Reactor material: | Safety restrictions: | ||
| Temperature: | High °C | Other: | |
| Feedstock and product details | |||
| Feedstock: | All lignocellulosic biomass, including wood and forestry residues, wheat straw, corn stover and bagasse | Product: | |
Open access pilot and demo facility providers
Patents
Currently no patents have been identified.
References
- ↑ Wikipedia, 2002: Hydrolysis 2002, Last access 2021. https://en.wikipedia.org/wiki/Hydrolysis
- ↑ P. Lenihan, A. Orozco, E. O’Neill, M.N.M. Ahmad, D.W. Rooney, G.M. Walker, 2010-01-15: Dilute acid hydrolysis of lignocellulosic biomass. Chemical Engineering Journal, Vol. 156, (2), 395–403. doi: https://doi.org/10.1016/j.cej.2009.10.061
- ↑ Katarzyna Świątek, Stephanie Gaag, Andreas Klier, Andrea Kruse, Jörg Sauer, David Steinbach, 2020-04-17: Acid Hydrolysis of Lignocellulosic Biomass: Sugars and Furfurals Formation. Catalysts, Vol. 10, (4), 437. doi: https://doi.org/10.3390/catal10040437
- ↑ a b Alessandra Verardi, Isabella De Bari, Emanuele Ricca and Vincenza Calabrò, 2012: Hydrolysis of Lignocellulosic Biomass: Current Status of Processes and Technologies and Future Perspectives. Bioethanol. Marco Aurelio Pinheiro Lima and Alexandra Pardo Policastro Natalense (Ed.). IntechOpen, {{{place}}}.
- ↑ S. Niju, M. Swathika, M. Balajii, 2020-01-01: Pretreatment of lignocellulosic sugarcane leaves and tops for bioethanol production. Lignocellulosic Biomass to Liquid Biofuels, Vol. , 301–324. doi: https://doi.org/10.1016/B978-0-12-815936-1.00010-1
- ↑ a b Valery B. Agbor, Nazim Cicek, Richard Sparling, Alex Berlin, David B. Levin, 2011-11: Biomass pretreatment: Fundamentals toward application. Biotechnology Advances, Vol. 29, (6), 675–685. doi: https://doi.org/10.1016/j.biotechadv.2011.05.005
- ↑ Amit K. Jaiswal, Rajeev Ravindran, 2016-01-01: A comprehensive review on pre-treatment strategy for lignocellulosic food industry waste: Challenges and opportunities. Bioresource Technology, Vol. 199, 92–102. doi: https://doi.org/10.1016/j.biortech.2015.07.106
- ↑ Moyer, P., Kim, K., Abdoulmoumine, N. et al., 2018: Structural changes in lignocellulosic biomass during activation with ionic liquids comprising 3-methylimidazolium cations and carboxylate anions 27/09/2018, Last access 06/12/2021. https://biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068-018-1263-0
- ↑ D. Lachos-Perez, F. Martinez-Jimenez, C. A. Rezende, G. Tompsett, M. Timko, T. Forster-Carneiro, 2016-02-01: Subcritical water hydrolysis of sugarcane bagasse: An approach on solid residues characterization. The Journal of Supercritical Fluids, Vol. 108, 69–78. doi: https://doi.org/10.1016/j.supflu.2015.10.019
10. The Nature of Lignocellulosics and Their Pretreatments for Enzymatic Hydrolysis L. T. Fan, Young-Hyun Lee and M. M. Gharpuray Department of Chemical Engineering Kansas State University Manhattan, KS 66506/U.S.A.