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This article outlines the technical and economic potentials of lignin in unlocking sustainable biorefineries. The benefits of using this highly functionalized biopolymer for the growth of sustainable economy have been highlighted. But practically, the possibility of commercially substituting petroleum oil with lignin is still not very high as the estimated biofuel production cost is 2–3 times higher than the former one. However, with the advancement in technology and more efficient measures by biorefineries such as storing and processing the biomass near the field so as to reduce the transportation cost, it is possible to gain higher profits. Companies like Domtar, Stora Enso, Borregaard’s LignoTech, VITO, and Chemelot InSciTe have been promoting commercial value of lignin. The growth of lignin market after the start-up production at various sites has been discussed in this review. Combining the complete “start-to-finish” analysis with economic evaluation gives a pragmatic overview of the possibilities whether lignin will join petroleum oil as an efficient and cost-effective renewable source.
The past decade has been quite interesting in terms of dealing with chemicals, energy and renewable resources—especially lignocellulosic biomass. The major raw materials for transportation, energy and chemicals in the latter half of the 20th century has been mainly the “crude” or “petroleum” oil. Processing crude oil has always been a chief task and technologies have been developing since 1860s for the same. Currently, several refineries/industrial plants have been developed that are highly advanced including hi-tech integrated devices (
Remarkably, in this revolutionizing world, not only the growth of bio-economy (involving natural feedstocks) has been a great achievement, but also the society’s attitude towards the utilization of renewables such as lignocellulosic biomass as source of energy has changed significantly (
Lignin is an untouched natural gem—at least from the bio-economy point of view, representing about 10-35% of lignocellulose biomass consisting of various phenylpropanoids (aromatic building blocks), thereby a potential source of fuel, energy, and chemicals including pharmaceuticals, paints, and plastics (
Lignin being a highly complex polymer with variable structures (like molecular weight distribution, chemical functionalities, etc. depending upon the biomass source and fractionation process), the valorization of lignin into value-added products is still challenging (
Valorization or processing of lignin is mainly targeted to obtain a product (either pure or mixture) that fits into a particular purpose, and the by-products obtained are regarded as residue. But this is not in accordance with the “atom economy” principle of Green Chemistry (
An understanding of all of the interconnected stages starting from the extraction of lignocellulose from its source (mainly trees), its transportation to the bio-refineries and finally the conversion of the initial biomass feedstock into intended lignin-derived product (with no by-products) is very important. In spite of the high potential of lignin to be used as an alternative to petroleum or crude oil, it can only be made commercially available if it is easily affordable by the common people. In this article, we aim to present an analysis on the potential of lignin as an emerging petroleum alternative and current efforts/hurdles in commercialization process.
The isolation of lignin from lignocellulosic biomass is targeted from high lignin containing sources such as woody biomass, i.e., hardwoods and softwoods in the bio-refineries producing “biofuel” along with lignin (
The production of biofuels in biorefineries are economically unfeasible unless a maximum yield of fermentable sugars followed by maximum bioconversion is achieved (
To gain market access, several developments have been carried out to cut short the processing cost and prove its credentials to compete with petroleum-based counterparts. One of the best strategies to gain wide-ranging economic benefits is by carrying out “genetic engineering.” It aims at reducing the energy intake for breaking down the biomass and thereby, making the whole process more cost-effective. Scientists at Scion, New Zealand, in collaboration with the University of Wisconsin, have successfully engendered pine trees genetically containing syringyl units (mostly occurring in hardwoods). These genetically engineered species now comprise more labile linkages in the lignin backbone, thus, making its processing far easier (
World’s first investigations into commercial development and application of lignin were performed in 1934 at Rothschild, Wisconsin, USA. After 1971, there was a significant increase in the sale of lignin, hence, new grades of purified lignin products started fabricating. Over the recent 10 years, the industry has observed several successful attempts in developing and expanding commercially relevant lignin processes. The world’s first large-scale lignin manufacturing plant started at Domtar’s Plymouth mill (NC, United States) in 2013, where LignoBoost®, a patented lignin extraction process, was employed in a kraft pulp mill is employed to produce high-quality lignin. This plant has an annual capacity of 25,000 MT of lignin along with 466,000 ADMT (Air Dry Metric Ton) of softwood kraft pulp from South Pinewood and now markets the lignin as BioChoice™ lignin (
Commercial and pre-commercial lignin-based technologies.
Ventures | Lignin type | Technology | Major product | Commercialization level and scale (dry metric ton) |
---|---|---|---|---|
Domtar |
Kraft | LignoBoost |
BioChoice™ lignin | Commercial, 25 k |
Stora Enso ( |
Kraft | LignoBoost | BioChoice™ lignin | Commercial, 50 k |
Ingevity ( |
Kraft | — | Indulin® AT | Commercial, — |
Borregaard LignoTech ( |
Lignosulfonate | Vanillin and other biopolymers | Commercial, 366 k (2021 sales volume) | |
UPM ( |
BioChoice™ lignin ( |
— | BioPiva™, Phenolic-type resin | Commercial, >20 k |
Suzano Papel e Cellulose ( |
Kraft | — | Ecolig | Commercial, 20 k |
Avantium ( |
Acid hydrolysis (HCl) lignin | Dawn Technology™ | Bio-asphalt | Pilot, — |
Independent Flemish Research Organization (VITO) ( |
— | — | Bio-aromatics | Pilot, — |
Vertoro ( |
Biorefinery and technical lignins ( |
— | Marine fuel | Technology licensing |
Pure Lignin Environmental Technology Ltd. (PLET) | Acid hydrolysis (dilute nitric acid) ( |
— | Water-soluble lignin | Technology licensing |
BENANOVA ( |
— | — | Colloidal- and nano- particles | — |
Spero Renewables LLC ( |
— | — | Thermoset polymers | — |
RenFuel AB ( |
— | — | Bio-oil and bio-plastics | — |
Bloom Biorenewables Ltd (Bloom Biorenewables, 2022) | — | Aldehyde-assisted fractionation | Variety of bio-products | — |
Currently a paper excellence subsidiary.
LignoBoost is process patented by Valmet (Espoo, Finland).
Large quantities of lignin are expected to be produced from paper and pulp industries in the coming years. According to the international lignin institute (ILI), about 40–50 million MT of lignin is being produced worldwide, currently (
This review highlighted the need, potential, and emergence of underutilized biopolymer, i.e., lignin, since it is the nature’s prime reserve of functional groups and aromatics. Owing to its high abundance and functionalization, lignin can be considered as the best substituent in tomorrow’s energy, fuel and chemical sectors. Lignin can be used in diverse applications, depending on its original source and method of extraction. However, commercialization of the biofuel production for the economic development is still a challenge mainly because of its complex nature and scarce information on extraction protocols. Moreover, the bio-refining processes for the extracted of lignin are economically infeasible. In order to compete with the cost of petrol or diesel, energy efficient technologies must be employed to reduce the biofuel processing cost. Biorefineries should focus on the complete conversion of feedstock into valuable products. Based on public awareness and extraordinary efforts by companies like Borregaard LignoTech, VITO and Chemelot (
Inspite of the high natural abundance and polyaromatic nature, lignocellulosic biomass is still not a commercially available feedstock for biofuel production. Methods for the extraction and purification of lignin are complex and expensive, consequently, cannot be employed at large-scales. The advancement in technology along with intensive collaboration among teams of different disciplines such as catalysis, chemical engineering and processing, analytics, etc. and boundaries is the key to solving problem. Big companies should establish commercial grade biorefineries that could produce several million gallons of fuel per year. The location of the biorefinery is very important for the economic transportation of the feedstock. In the coming years, biorefineries can be designed to utilize energy from renewable resources like solar, wind and geothermal, or we can even collocate them near thermal plants (coal or nuclear). This will help in preserving other non-renewable sources of energy such as natural gas. In view of above discussion about the pros and cons of using a sustainable biofuel, should not lignin be given the same chance as petroleum or crude oil?
The United States Government and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525 (SAND No. SAND2022-15460 J).
HC and BAS conceptualized; VJ wrote the original draft; All authors edited the manuscript.
This work was part of the DOE Joint BioEnergy Institute (
The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.
ABPDU would also like to thank the support from The Bioenergy Technologies Office (BETO) within the US DOE's Office of Energy Efficiency and Renewable Energy. Authors also thank Xiao Jiang of North Carolina State University in scouting the lignin technologies.
Author SS and HC were employed by company Sandia National Laboratories.
The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.