Extraction of Cellulose and Nanocellulose from the Green Seaweed Ulva sp.1 for Characterisation and Investigation of Processing Effects
(2020) KETM05 20201Chemical Engineering (M.Sc.Eng.)
- Abstract
- Development of valuable products from downstream process residual biomasses and profound reduction of waste are two key components for developing a more sustainable process industry. The importance of bio-renewable feedstocks and bio-based processing techniques are also crucial in the transformation to a more sustainable and green society. Therefore focus is directed on full exploitation of seaweed biomass from the genus Ulva for extraction of valuable products and for waste minimisation. The Ulva biomass grown during bioremediation of process wastewaters is subjected to a biorefinery sequence in order to fully utilize the biomass, where seaweed salt, soluble fibre (ulvan) and protein for which the yield and quality is briefly reported.... (More)
- Development of valuable products from downstream process residual biomasses and profound reduction of waste are two key components for developing a more sustainable process industry. The importance of bio-renewable feedstocks and bio-based processing techniques are also crucial in the transformation to a more sustainable and green society. Therefore focus is directed on full exploitation of seaweed biomass from the genus Ulva for extraction of valuable products and for waste minimisation. The Ulva biomass grown during bioremediation of process wastewaters is subjected to a biorefinery sequence in order to fully utilize the biomass, where seaweed salt, soluble fibre (ulvan) and protein for which the yield and quality is briefly reported. This work further extends this biorefinery by targeting the cellulose rich residual biomass, a promising feedstock material for further development of high quality products. The residual biomass is pulped to assess the suitability of this lignin free residual biomass as a feedstock for nanocellulose production. The cellulose pulp products had a high content of glucose with residual xyloglucan present. Solid-state cross-polarization magnetic angle spinning NMR spectroscopy measurements indicated a crystalline diameter of the order 1.6-3.2 nm. Crystalline nanocellulose (CNC) products, prepared by a strong acid hydrolysis using 40, 50 and 60% H2SO4 (50 min, 50°C) were isolated in moderate to low yields 43.1-48.9%, 25.9-30.6% and 15.7-20.0%, respectively, with evidence of significant carbonization at higher acid concentrations. Cellulose nanofibrils (CNF) were prepared in high yield (49.3%-81.6) by mechanical disintegration with the effect of 2,2,6,6-Tetramethylpiperidin-1-yl-oxyl-oroxidanyl (TEMPO) -oxidation assessed. The degree of disintegration was positively related to the degree of oxidation of the cellulose pulp. It is concluded that the residual Ulva biomass is a valuable feedstock for CNF production, or potentially bioethanol as the small crystal size might be more facile to enzymatic attack. (Less)
- Popular Abstract
- This master thesis was carried out at the Marine Field Station at Waikato University, campus Tauranga, New Zealand. The research extends around the usability of seaweed biomass from green seaweed (Ulva sp.1) for extraction of valuable products such as seaweed salt, bioactive cell wall compounds (ulvan), seaweed protein and more specifically in this work, cellulose. The seaweed salt is as a healthy replacement for normal table salt whilst ulvan can be used for dietary supplements and medical applications and the seaweed. The seaweed protein is a good alternative protein source that can be used in for example animal feed or human supplements. Cellulose, is one of the most common compounds in our nature and is present in every cell of land... (More)
- This master thesis was carried out at the Marine Field Station at Waikato University, campus Tauranga, New Zealand. The research extends around the usability of seaweed biomass from green seaweed (Ulva sp.1) for extraction of valuable products such as seaweed salt, bioactive cell wall compounds (ulvan), seaweed protein and more specifically in this work, cellulose. The seaweed salt is as a healthy replacement for normal table salt whilst ulvan can be used for dietary supplements and medical applications and the seaweed. The seaweed protein is a good alternative protein source that can be used in for example animal feed or human supplements. Cellulose, is one of the most common compounds in our nature and is present in every cell of land based plants, but also to some extent in seaweed and bacteria and other primitive marine organisms. It consist of up to 100 000 single glucose molecules bonded to each other in a complex woven structure. Some parts of the structure are crystalline and some parts amorphous allowing different treatments to be used to target different products. The natural abundance and renewable nature of cellulose and its specific chemistry makes it a valuable resource with many different applications. Cellulose is also biodegradable and non-toxic, and thus a sustainable alternative to petrochemically derived materials.
Seaweed of the genus Ulva has been shown to effectively clean process waste waters as it uses the nutrients present in these waters in its growth and the Ulva biomass accumulates in the system. By harvesting and subjecting this biomass to a biorefinery sequence, including various techniques and treatments, the valuable products mentioned above can be extracted from the bioremediating seaweed, introducing a concept of full exploitation to this fantastic nature resource.
Seaweed salt, ulvan and proteins were extracted and briefly characterized since the work was focused on characterizing products from cellulose. The residual cellulose rich biomass from a cascading biorefinery targeting seaweed salt, ulvan and proteins was bleached, and further treated to obtain a product mainly constituting of cellulose called pulp. The cellulose pulp was treated in different ways to obtain products suitable for application. Acid treatment was used to access the ordered parts of the cellulose, the crystals, with a size range in the nanometre scale, called crystalline nanocellulose or CNC. This product was then studied in terms of shape, size, degree of crystallinity, structure and composition. By instead treating the pulped cellulose mechanically in a laboratory homogeniser it can cause the cellulose to fibrillate into fibrils with a width in the nanometre scale. Cellulose nanofibrils or CNFs are made up of both the ordered and non-ordered parts of the cellulose and was characterized based on structure, composition and degree of defibrillation. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9025895
- author
- Fransson, Matilda LU
- supervisor
- organization
- course
- KETM05 20201
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Seaweed, Cellulose, Nanocellulose, Chemical engineering, Kemiteknik
- language
- English
- id
- 9025895
- date added to LUP
- 2020-09-14 15:51:29
- date last changed
- 2020-09-14 15:51:29
@misc{9025895,
abstract = {{Development of valuable products from downstream process residual biomasses and profound reduction of waste are two key components for developing a more sustainable process industry. The importance of bio-renewable feedstocks and bio-based processing techniques are also crucial in the transformation to a more sustainable and green society. Therefore focus is directed on full exploitation of seaweed biomass from the genus Ulva for extraction of valuable products and for waste minimisation. The Ulva biomass grown during bioremediation of process wastewaters is subjected to a biorefinery sequence in order to fully utilize the biomass, where seaweed salt, soluble fibre (ulvan) and protein for which the yield and quality is briefly reported. This work further extends this biorefinery by targeting the cellulose rich residual biomass, a promising feedstock material for further development of high quality products. The residual biomass is pulped to assess the suitability of this lignin free residual biomass as a feedstock for nanocellulose production. The cellulose pulp products had a high content of glucose with residual xyloglucan present. Solid-state cross-polarization magnetic angle spinning NMR spectroscopy measurements indicated a crystalline diameter of the order 1.6-3.2 nm. Crystalline nanocellulose (CNC) products, prepared by a strong acid hydrolysis using 40, 50 and 60% H2SO4 (50 min, 50°C) were isolated in moderate to low yields 43.1-48.9%, 25.9-30.6% and 15.7-20.0%, respectively, with evidence of significant carbonization at higher acid concentrations. Cellulose nanofibrils (CNF) were prepared in high yield (49.3%-81.6) by mechanical disintegration with the effect of 2,2,6,6-Tetramethylpiperidin-1-yl-oxyl-oroxidanyl (TEMPO) -oxidation assessed. The degree of disintegration was positively related to the degree of oxidation of the cellulose pulp. It is concluded that the residual Ulva biomass is a valuable feedstock for CNF production, or potentially bioethanol as the small crystal size might be more facile to enzymatic attack.}},
author = {{Fransson, Matilda}},
language = {{eng}},
note = {{Student Paper}},
title = {{Extraction of Cellulose and Nanocellulose from the Green Seaweed Ulva sp.1 for Characterisation and Investigation of Processing Effects}},
year = {{2020}},
}