Lignin Biorefinery: An effective Biomass conversion to Value added Product

Introduction

An abundance in lignocellulosic biomass globally can emerge as an important solution for ever increasing fuel and chemical demands. A sustainable conversion of the biomass in the value-added products, sugars and fuels, i.e. a sustainable biorefinery seems to be the future of effective biomass utilization.

Lignin, which is one of the most abundant polysaccharides in term of its global availability, appears to be a suitable raw material. Nearly 150 billion tonnes of lignin is annually produced out of which 415 million tonnes is produced from five major crops around the globe. Therefore, it is evident that a vast amount of carbon energy is stored in the lignocellulosic biomass in the form of lignin and other polysaccharides, the full potential of which remains untapped. The lignocellulosic biomass is composed of cellulose, hemicellulose and lignin, out of which, the aromatic nature of lignin carries a greater vitality as to its ability to be converted into various value-added chemicals and polymers. Therefore, the development of technology for the effective recovery and the conversion of lignin in biorefinery has taken a more significant leap in recent times. Hence, a sequential conversion of lignin into varied products is what we can call as a lignin biorefinery/lignin valorization. In this article, we shall have a closer look towards the major products being developed from the lignin base, intellectual property trends and market forecast in this direction.

Lignin, its Valorization & products

Though we have already discussed the availability and abundance of lignin, and despite the availability  its extraction and easy recovery remains a technological challenge.

Further, lignin is a major byproduct of the paper and pulp industry which can be used for its valorization via biorefinery based product conversions (Fig.1)

Lignin being an aromatic polymer, containing coumaryl- (H), coniferyl- (G) and sinapyl (S) phenolic structures acts as a cementing material in the plant cell wall and provides the rigidity to the plant. The type of lignin present in a plant cell wall will depend upon the relative concentration of these phenolics and plant species. Therefore different mode of conversions are used for the production of different products, depending upon the type of lignin. On the basis of the physicochemical characteristics, the lignins can be classified as lignosulphonates, krafts lignin, soda lignin, organosolv lignin, etc. Further, these different types are put into use through different industrial applications. Kraft Lignin is the main byproduct in the paper and pulp industry, and second generation in bioethanol production industry. While 98% of it is used as a fuel for energy production, a mere 2% is used as for the different polymeric products. Lignin alone is having a greater calorific value as compared to the lignocellulose biomass. Other than energy production, it is used in the production of:

Dispersants : In dyes, construction industry , Jet printing ink, Oil Well Drilling Muds etc.

Emulsifiers : It is added in asphalt to make temperature stable asphalt emulsions

Aromatics: The production of vanillin, benzene,  toluene, xylene and styrene etc.

Polymers : Bio-based polyethylene terephthalate (PET), poly-urethane etc. can be produced from lignin and their demand can be met for a significant time in future. Further with more refined and advanced biorefinery approach, an improved and purified lignin can be isolated with their greater applications in the pharmaceuticals, fragrances and flavoring agent.

fig1Fig1. Low to high value lignin derived products

Intellectual Property(IP) Trend

Since there is constant innovation in the lignin driven biorefinery based research, there is a very significant rise in the IP trend as well (Fig.2 -Fig.9). If we look at the major innovators/assignee in this domain, we see API intellectual property holdings up top. However, the academic institutions makes a very significant share in the overall IP trend.                              

fig2Fig 2. Major Assignees involved in lignin driven research

           fig3

Fig 3. IP trend amongst the industry, academia and independent inventors

Similarly, if we look at the different patent applications, publication trend, it has risen significantly in the past decade, which is a clear indication of emerging interest of the different innovators in the lignin biorefinery.

             fig4Fig 4. Year wise patent priority trend

           fig5Fig 5. Year wise patent application trend

             fig6

Fig 6. Year wise patent publication trend                   

Also, if we see the number of applications published with respect to the granted applications, the difference is very significant which indicates an acceleration in the lignin biorefinery oriented research.

                   fig7Fig 7. Total patents applications and grants in the lignin biorefinery

fig8

Fig 8. Country wise publication trend

  fig9

Fig 9. Year wise filing trend of top ten assignee

Therefore, it is safe to say that in the near future there is a greater possibility of commercial production of the lignin based value added products with much advanced technologies and processes.

Market Trends

The lignin is emerging as a very potent alternative/precursor for various aromatics and polymers. The market is expected to grow at the rate of 3.42% during the period 2018-2023 from current 974.6 million, where it may form a major share in the cement industry as a cement additive. If we look at the global scenario, Europe appears to be the major market for lignin based products which currently accounts for approximately 34% of the total market share. Therefore, it is reasonable to say that the research and innovation in the lignin biorefinery is going to see a greater boom in the near future, drifting the current manufacturing and construction practices towards greener alternatives.  

Conclusion

The inclination of the world towards the greener production methods and technologies, and the thrust for efficient usage of the abundant lignocellulosic biomass has given rise to the lignin biorefinery concept, which has already made a significant technical progress in recent past. Therefore, it is very much likely that the lignin or lignocellulosic biomass based chemicals, polymers and fuels will be a distinct reality in the near futur

References

  • Francesco Cherubini., The biorefinery concept: Using biomass instead of oil for producing energy and chemicals. Department of Energy and Process Engineering, Norwegian University of Science and Technology (NTNU),
  • Hu J, Zhang Q, Lee DJ ., Kraft lignin biorefinery: A perspective. Collaborative Innovation Center of Biomass Energy, Henan Agricultural University
  • Global Lignin Market by Products (Lignosulfonate, Kraft Lignin and Others), by Applications (Concrete Additives, Animal Feed, Dyestuff, Others) and by Geography by research and markets.
  • Compere AL, Griffith WL.,Preparation and analysis of biomass lignins. Chemical Sciences Division, Oak Ridge National Laborator