Biocatalysis and biomass conversion: enabling a circular economy

Author(s):  
Roger A. Sheldon

This paper is based on a lecture presented to the Royal Society in London on 24 June 2019. Two of the grand societal and technological challenges of the twenty-first century are the ‘greening' of chemicals manufacture and the ongoing transition to a sustainable, carbon neutral economy based on renewable biomass as the raw material, a so-called bio-based economy. These challenges are motivated by the need to eliminate environmental degradation and mitigate climate change. In a bio-based economy, ideally waste biomass, particularly agricultural and forestry residues and food supply chain waste, are converted to liquid fuels, commodity chemicals and biopolymers using clean, catalytic processes. Biocatalysis has the right credentials to achieve this goal. Enzymes are biocompatible, biodegradable and essentially non-hazardous. Additionally, they are derived from inexpensive renewable resources which are readily available and not subject to the large price fluctuations which undermine the long-term commercial viability of scarce precious metal catalysts. Thanks to spectacular advances in molecular biology the landscape of biocatalysis has dramatically changed in the last two decades. Developments in (meta)genomics in combination with ‘big data’ analysis have revolutionized new enzyme discovery and developments in protein engineering by directed evolution have enabled dramatic improvements in their performance. These developments have their confluence in the bio-based circular economy. This article is part of a discussion meeting issue ‘Science to enable the circular economy'.

2018 ◽  
Vol 156 ◽  
pp. 03054 ◽  
Author(s):  
Asfarina Zumalla ◽  
Budiyono ◽  
Siswo Sumardiono

Biogas is one alternative to replace the irreplaceable energy source that has begun to diminish its existence. The raw materials for biogas manufacture are renewable biomass, usually using plantation waste, agriculture, and livestock. Using biogas can also reduce environmental pollution. One of the agricultural waste that has great potential to become the raw material of biogas is teak sawdust. Wood processing industry in Indonesia quite a lot, but wood has a high lignosesluosa content, so it needs the right method to process it. With the delignification of lignin levels on teak sawdust will decrease. Wood sawdust is soaked using NaOH for 1, 2, 3, and 4 days with 4% w / v concentration. The lowest lignin and hemicellulose content was 25.79% and 87.9% in pretreatment for 4 days, while the highest cellulose level was 57, 34%. The accumulated volume of biogas at 1 day pretreatment, ie 709 ml / g TS. Gcms shows the enlarged peak area of methanamine, N-methyl from before pretreatment. The fastest biogas formation (λ) in 4 days pretreatment, 1.60403 days and the largest constant A and U variables at 1 day were 914.5903 ml / g TS and 34.59765 ml / g TS.


2016 ◽  
Vol 13 (116) ◽  
pp. 20160087 ◽  
Author(s):  
Roger A. Sheldon

The grand challenge facing the chemical and allied industries in the twenty-first century is the transition to greener, more sustainable manufacturing processes that efficiently use raw materials, eliminate waste and avoid the use of toxic and hazardous materials. It requires a paradigm shift from traditional concepts of process efficiency, focusing on chemical yield, to one that assigns economic value to replacing fossil resources with renewable raw materials, eliminating waste and avoiding the use of toxic and/or hazardous substances. The need for a greening of chemicals manufacture is readily apparent from a consideration of the amounts of waste generated per kilogram of product (the E factors) in various segments of the chemical industry. A primary source of this waste is the use of antiquated ‘stoichiometric’ technologies and a major challenge is to develop green, catalytic alternatives. Another grand challenge for the twenty-first century, driven by the pressing need for climate change mitigation, is the transition from an unsustainable economy based on fossil resources—oil, coal and natural gas—to a sustainable one based on renewable biomass. In this context, the valorization of waste biomass, which is currently incinerated or goes to landfill, is particularly attractive. The bio-based economy involves cross-disciplinary research at the interface of biotechnology and chemical engineering, focusing on the development of green, chemo- and biocatalytic technologies for waste biomass conversion to biofuels, chemicals and bio-based materials. Biocatalysis has many benefits to offer in this respect. The catalyst is derived from renewable biomass and is biodegradable. Processes are performed under mild conditions and generally produce less waste and are more energy efficient than conventional ones. Thanks to modern advances in biotechnology ‘tailor-made’ enzymes can be economically produced on a large scale. However, for economic viability it is generally necessary to recover and re-use the enzyme and this can be achieved by immobilization, e.g. as solid cross-linked enzyme aggregates (CLEAs), enabling separation by filtration or centrifugation. A recent advance is the use of ‘smart’, magnetic CLEAs, which can be separated magnetically from reaction mixtures containing suspensions of solids; truly an example of cross-disciplinary research at the interface of physical and life sciences, which is particularly relevant to biomass conversion processes.


Nafta-Gaz ◽  
2021 ◽  
Vol 77 (6) ◽  
pp. 389-399
Author(s):  
Zygmunt Burnus ◽  
◽  
Agnieszka Wieczorek ◽  

In this work, the possibilities of using the GC-FID gas chromatography technique for determination of mono- and diacylglycerols content in the stream from the co-hydrogenation of rapeseed oil and middle distillates were investigated. Products from this process are planned to be increasingly used in the future as a new biocomponent of fuel for diesel engines. Before introducing new types of fuel components, it is necessary to test them in detail, especially in terms of residues of the fat raw material. The Regulation of the Minister of Climate of June 24, 2020 on the content of biocomponents formed as a result of co-hydrogenation indicates that the level of biomass conversion is determined on the basis of the content of triacylglycerols in the hydro-raffinate. Hence, on the basis of this determination, it is possible to assess the correctness of the co-hydrogenation process. However, other fatty components may be present in the product of this process in the form of unreacted residues. Therefore, it seems justified to carry out studies on other trace components of fatty origin in the hydro-treating material, due to the introduction of various plant materials together with petroleum hydrocarbons into the co-hydrogenation process. Due to the lack of available standardized methodologies for testing this type of products, a review of the literature was made regarding the possibility of using analytical techniques including gas and liquid chromatography to determine content of the so-called mono- and dicylglycerols, being residues of the fatty raw material, in various types of matrices, including vegetable oils and fatty acid methyl esters. In the case of examining the content of mono- and diacylglycerols in the product from the co-hydrogenation process, it was necessary to use the technique of liquid chromatography for the first-step concentration of the substances of interest. This technique made it possible to separate the sample matrix and concentrate the components to be determined prior to gas chromatographic analysis. Due to the complicated matrix of samples and the low required level of quantification, it was necessary to select appropriate conditions for removing the matrix using the classical liquid chromatography technique. A proprietary methodology for testing the content of mono- and diacylglycerols in the hydro-raffinate was developed, which was used to test selected samples of real hydro-raffinates from the co-HVO and HVO co-hydrogenation process. The ability to detect these trace fat components at a low level was indicated – as low as 2 mg/kg. The obtained sensitivity of the method allowed for additional qualitative assessment of this type of co-hydrogenation products, which are gradually gaining importance on the European market of liquid fuels.


Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6684
Author(s):  
Magdalena Modelska ◽  
Michal J. Binczarski ◽  
Piotr Dziugan ◽  
Szymon Nowak ◽  
Zdzisława Romanowska-Duda ◽  
...  

Poland is one of the leading producers of sugar from sugar beet in Europe. However, the production of sugar generates large amounts of lignocellulosic waste, in the form of beet pulp and leaves. Currently, this waste is not reutilized in the chemical industry, but is only used as food for farm animals. This paper assesses the potential of using bio-waste from the sugar industry as a raw material for the production of furfurals via acid hydrolysis. Further processing of furfural into derivatives such as furfuryl alcohol (FA) or tetrahydrofurfuryl alcohol (THFA) could increase the economic profitability of the initiative. Furfuryl alcohol can be used as a fuel additive in sugar factories. Tetrahydrofurfuryl alcohol can be used as a component in agricultural fertilizers, increasing the yield of sugar beet. This approach reduces the amount of post-production waste and brings the sugar industry closer to the concept of a circular economy.


Author(s):  
Anna Fajdek-Bieda ◽  
Agnieszka Wróblewska ◽  
Piotr Miądlicki ◽  
Jadwiga Tołpa ◽  
Beata Michalkiewicz

AbstractThis work presented the studies with the natural zeolite—clinoptilolite as the catalyst for the isomerization of geraniol. During the research, it turned out that the studied process is much more complicated, and not only isomerization takes place in it, but also dehydration, oxidation, dimerization, cyclization and fragmentation of the carbon chain. Geraniol is an organic raw material which can be obtained not only by a chemical synthesis but also from plants (renewable biomass) by distillation or extraction method, for example a source of geraniol can be a plant—geranium. Before catalytic tests clinoptilolite was characterized by the instrumental methods, such as: XRD, porosity studies—nitrogen adsorption at 77 K, SEM, EDXRF, and FT-IR. Gas chromatography analyses showed that the main products of geraniol isomerization process were 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol. The selectivity of 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol depended on the temperature, catalyst content and reaction time. These parameters were changed in the following ranges: 80–150 °C (temperature), 5–15 wt% (catalyst content) and 15–1440 min. (reaction time). The most favorable conditions for 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol obtaining were: temperature 140 ºC, catalyst content 12.5 wt% and reaction time 180 min. At these conditions, the conversion of geraniol amounted to 98 mol%, and the selectivities of 6,11-dimethyl-2,6,10-dodecatrien-1-ol and thumbergol amounted to 14 and 47 mol%, respectively.


Author(s):  
Ahmed I. Osman ◽  
Neha Mehta ◽  
Ahmed M. Elgarahy ◽  
Amer Al-Hinai ◽  
Ala’a H. Al-Muhtaseb ◽  
...  

AbstractThe global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800–1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.


2021 ◽  
Vol 3 (1) ◽  
pp. 243-259
Author(s):  
Yadhu N. Guragain ◽  
Praveen V. Vadlani

Lignocellulosic biomass feedstocks are promising alternatives to fossil fuels for meeting raw material needs of processing industries and helping transit from a linear to a circular economy and thereby meet the global sustainability criteria. The sugar platform route in the biochemical conversion process is one of the promising and extensively studied methods, which consists of four major conversion steps: pretreatment, hydrolysis, fermentation, and product purification. Each of these conversion steps has multiple challenges. Among them, the challenges associated with the pretreatment are the most significant for the overall process because this is the most expensive step in the sugar platform route and it significantly affects the efficiency of all subsequent steps on the sustainable valorization of each biomass component. However, the development of a universal pretreatment method to cater to all types of feedstock is nearly impossible due to the substantial variations in compositions and structures of biopolymers among these feedstocks. In this review, we have discussed some promising pretreatment methods, their processing and chemicals requirements, and the effect of biomass composition on deconstruction efficiencies. In addition, the global biomass resources availability and process intensification ideas for the lignocellulosic-based chemical industry have been discussed from a circularity and sustainability standpoint.


Author(s):  
Leonidas Milios

AbstractThe transition to a circular economy is a complex process requiring wide multi-level and multi-stakeholder engagement and can be facilitated by appropriate policy interventions. Taking stock of the importance of a well-balanced policy mix that includes a variety of complementing policy instruments, the circular economy action plan of the European Union (COM(2020) 98 final) includes a section about “getting the economics right” in which it encourages the application of economic instruments. This contribution presents a comprehensive taxation framework, applied across the life cycle of products. The framework includes (1) a raw material resource tax, (2) reuse/repair tax relief, and (3) a waste hierarchy tax at the end of life of products. The research is based on a mixed method approach, using different sources to analyse the different measures in the framework. More mature concepts, such as material resource taxes, are analysed by reviewing the existing literature. The analysis of tax relief on repairs is based on interviews with stakeholders in Sweden, where this economic policy instrument has been implemented since 2017. Finally, for the waste hierarchy tax, which is a novel proposition in this contribution, macroeconomic modelling is used to analyse potential impacts of future implementation. In all cases, several implementation challenges are identified, and potential solutions are discussed according to literature and empirical sources. Further research is required both at the individual instrument and at the framework level. Each of the tax proposals needs a more detailed examination for its specificities of implementation, following the results of this study.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Libo Zhang ◽  
Junyan Tan ◽  
Gangying Xing ◽  
Xintong Dou ◽  
Xuqiang Guo

AbstractConversion of the abundant agricultural residual cotton stalk (CS) into useful chemicals or functional materials could alleviate the fossil fuels caused energy shortages and environmental crises. Although some advances have been achieved, less attention has been paid to the plant tissues effect. In this study, the plant tissue of CS was changed by part degradation of some components (hemicelluloses and lignin, for example) with the aid of acid/base (or both). The pretreated CS was transformed into hydrochar by hydrothermal carbonization (HTC) method. Morphological and chemical compositions of CS hydrochar were analyzed by various techniques, including elemental analysis, Fourier transform infrared (FTIR), BET analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Methylene blue (MB) removal of prepared CS hydrochar was used to evaluate CS hydrochar pollutions adsorption capacity. Results reveal acid/base (or both) pretreatment is beneficial for CS raw material to prepare high-quality CS hydrochar. The effects of some parameters, such as initial MB concentration, temperature, pH value and recyclability on the adsorption of MB onto both acid and base-pretreated CS hydrochar (CS-H2SO4 + NaOH-HTC) were studied. The present work exhibits the importance of agricultural waste biomass material plant tissues on its derived materials, which will have a positive effect on the direct utilization of waste biomass.


Systems ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 38
Author(s):  
Raquel Balanay ◽  
Anthony Halog

This systematic review examines the importance of a systems/holistic approach in analyzing and addressing the footprints/impacts of business-as-usual activities regarding the development of a circular economy (CE). Recent works on why current CE approaches have to be examined in terms of reductionist vs. systems perspectives are reviewed to tackle questions pertaining to the right or the wrong way of CE implementation. ‘Doing the right thing right’ is essential for sustainability—the ultimate goal of a CE, which must be viewed as a system to begin with. The limited reductionist approach overlooks and thus cannot prognosticate on the formidable unintended consequences that emerge from ‘doing the right things wrong’, consequences that become too costly to undo. The systems approach, being holistic, is complicated and difficult to pursue but open to exciting opportunities to integrate innovations in CE analysis and implementation. Complexity is an inherent downside of the systems approach. However, both approaches are complementary, as reductionist models can be combined to create a system of comprehensive analysis to correct the approach towards implementation of current CE initiatives. This review reports that advancements in systems analytical frameworks and tools are highly important for creating general guidelines on CE analysis and implementation.


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