Periodic Reporting for period 1 - ENBIOMECH (Sustainable mechanochemical synthesis of nanomaterials from biomass)
Periodo di rendicontazione: 2021-06-01 al 2023-05-31
The ENBIOMECH project aimed to create sustainable and efficient methods for producing bio-based nanomaterials from cellulose and lignin using mechanochemistry and related solid-state synthetic approaches. Cellulose, a renewable resource, can yield valuable nanomaterials such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) through mechanical, chemical and/or enzymatic processing. Due to the high aspect ratio, tensile strength, and tunable surface chemistry, these nanomaterials have a strong impact on the properties of composite materials, making them highly sought after by various industries. For example, the food and beverage, textile, and personal care industries utilize nanocelluloses in sustainable packaging solutions, driving the demand for their production.
The overarching objectives of the ENBIOMECH project were:
- Develop mechanochemical technologies for efficient and renewable biocatalyst-based (enzyme) production of cellulose and lignin nanoparticles, and characterize the obtained materials.
- Create a facile mechanochemical method for covalently modifying CNCs with oligonucleotides, to create CNC-based self-sorting nanoscale building blocks.
- Investigate the supramolecular self-assembly of oligonucleotide-CNC nanoarrays.
The ENBIOMECH project made significant advances in transforming cellulose materials, namely in utilizing cellulase enzymes in solid-state reactions to transform cotton to cellulose nanomaterials and in mechanochemical modification of cellulose nanocrystals. Unlike traditional chemical synthesis and modification methods of CNCs, which require large volumes of caustic or toxic chemicals and clean water, the solvent-free cellulose modification methods developed within this project provide fast and environmentally benign approaches, that curb the amount of hazardous waste generated. As a result, the ENBIOMECH project contributes to EU priority topics, such as resource efficiency in sustainable forestry, promoting renewable materials, and environmentally conscious use of energy, water, and raw materials.
The ENBIOMECH project provided an opportunity for the researcher to return to Europe and build a scientific career aligned with the strong regional interest in biomass derived products. Through the programme, the researcher gained experience in leading independent research, project supervision and management, and building a wide scientific network, all of which have helped advanced her career.
The overarching objectives of the ENBIOMECH project were:
- Develop mechanochemical technologies for efficient and renewable biocatalyst-based (enzyme) production of cellulose and lignin nanoparticles, and characterize the obtained materials.
- Create a facile mechanochemical method for covalently modifying CNCs with oligonucleotides, to create CNC-based self-sorting nanoscale building blocks.
- Investigate the supramolecular self-assembly of oligonucleotide-CNC nanoarrays.
The ENBIOMECH project made significant advances in transforming cellulose materials, namely in utilizing cellulase enzymes in solid-state reactions to transform cotton to cellulose nanomaterials and in mechanochemical modification of cellulose nanocrystals. Unlike traditional chemical synthesis and modification methods of CNCs, which require large volumes of caustic or toxic chemicals and clean water, the solvent-free cellulose modification methods developed within this project provide fast and environmentally benign approaches, that curb the amount of hazardous waste generated. As a result, the ENBIOMECH project contributes to EU priority topics, such as resource efficiency in sustainable forestry, promoting renewable materials, and environmentally conscious use of energy, water, and raw materials.
The ENBIOMECH project provided an opportunity for the researcher to return to Europe and build a scientific career aligned with the strong regional interest in biomass derived products. Through the programme, the researcher gained experience in leading independent research, project supervision and management, and building a wide scientific network, all of which have helped advanced her career.
Three different commercially available cellulase enzymes were assessed in the production of cellulose nanocrystals (CNCs) from cotton (raw cotton balls and filter paper) after a brief period of ball milling (15 or 30 minutes) and after subsequent static incubation (24 or 72 hours of aging at 55 °C). Conditions that favour partial hydrolysis of cellulose (to yield CNCs) were identified by gel-permeation chromatography, powder X-ray diffraction and atomic force microscopy, which showed that the hydrolysis degree (DPn, DPw and ÐM), increase of cellulose crystallinity and nanoscale morphology is achieved already after 15 minutes of ball milling in the presence of cellulase enzymes. These results provide a rapid low-waste and acid-free method to generate CNCs (manuscript in preparation).
Isolation of lignin from Aspen sawdust (69.9% holocellulose, 18.8% Klason lignin, 3.5% acid soluble lignin, 1.6% extractives, 0.38% ash and 6.1% other), on the other hand, was not successful in the mechano-enzymatic approach using the commercially available cellulases, due to limited conversion of cellulose to glucose in the reaction conditions employed.
Chemical modification of cellulose nanomaterials through mechanochemistry and/or accelerated aging was explored in ENBIOMECH, producing a protocol that was significantly faster (30 minutes, compared to 24 h), less toxic (avoiding DMF) and less wasteful (solvent amount reduced 124x) compared to an equivalent reaction in a heterogeneous solution. The protocol was used in this project to create self-sorting biobased building blocks, which were then explored in forming CNC-based nanoarrays. Work is ongoing on these topics, and will be completed after the programme.
Through supervision of Ph.D. and M.Sc. students during the ENBIOMECH project, solvent-free modification of cellulose (two projects) and synthesis of pigments (one project) was achieved, resulting, so far, in one publication and one manuscript under review.
Isolation of lignin from Aspen sawdust (69.9% holocellulose, 18.8% Klason lignin, 3.5% acid soluble lignin, 1.6% extractives, 0.38% ash and 6.1% other), on the other hand, was not successful in the mechano-enzymatic approach using the commercially available cellulases, due to limited conversion of cellulose to glucose in the reaction conditions employed.
Chemical modification of cellulose nanomaterials through mechanochemistry and/or accelerated aging was explored in ENBIOMECH, producing a protocol that was significantly faster (30 minutes, compared to 24 h), less toxic (avoiding DMF) and less wasteful (solvent amount reduced 124x) compared to an equivalent reaction in a heterogeneous solution. The protocol was used in this project to create self-sorting biobased building blocks, which were then explored in forming CNC-based nanoarrays. Work is ongoing on these topics, and will be completed after the programme.
Through supervision of Ph.D. and M.Sc. students during the ENBIOMECH project, solvent-free modification of cellulose (two projects) and synthesis of pigments (one project) was achieved, resulting, so far, in one publication and one manuscript under review.
The ENBIOMECH project and collaborative (solid-state chemistry) projects that were carried out during the reporting period have generated safe and sustainable protocols for making and modifying bio-based nanomaterials and for the synthesis of phthalocyanine dyes. Considering the worldwide production scale of these useful, yet poorly soluble materials, the conscious use of energy, water and raw materials in the herein developed methods carry a wider societal impact, contributing towards sustainable consumption and production patterns (Sustainable Development Goal no. 12).