Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions
Thesis (PhD)--Stellenbosch University, 2025.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
Stellenbosch : Stellenbosch University
2026
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613836671975424 |
|---|---|
| access_status_str | Open Access |
| author | Sikazwe, Manasseh Kafula |
| author2 | Görgens, Johann |
| author_browse | Görgens, Johann Sikazwe, Manasseh Kafula |
| author_facet | Görgens, Johann Sikazwe, Manasseh Kafula |
| author_sort | Sikazwe, Manasseh Kafula |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2025. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/134821 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:42:28.529Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/134821 Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions Sikazwe, Manasseh Kafula Görgens, Johann Louw, Jeane Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Sugarcane industry -- Technological innovations Microbial biotechnology Biological products Strain theory (Chemistry) Sugarcane -- Propagation Fermentation Greenhouse gas mitigation Biomass conversion Thesis (PhD)--Stellenbosch University, 2025. Sikazwe, M. K. 2025. Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/3e55ec7b-7de7-49f0-b82c-249f7beec81a ENGLISH ABSTRACT: Biorefineries are sustainable production models that can help lower greenhouse gas (GHG) emissions and reduce the reliance on petrochemical raw materials, promoting a sustainable future. When integrated with sugarcane mills, they can lower energy costs and cushion financial losses due to fluctuations in sugar production and market disparities. Various high-value chemicals are promising candidates for direct microbial conversion of sugarcane molasses sugars, potentially replacing excess sucrose production and creating new revenue streams. However, the technology for direct microbial production of most high-value products is not mature enough for commercial application. Enhancing strain and bioprocess performances through synthetic biology and metabolic engineering can produce desirable financial and environmental benefits, as demonstrated by the breakthrough in the commercialization of biobased 1,3-propanediol (1,3-PDO), raising the question of whether similar technology developments should be applied to other potential products. However, these research and development (R&D) efforts require substantial financial investment over extended development periods and should be committed to products with strong financial, environmental, and ultimately commercial application potential. This study assessed multiple process scenarios for the production of 2,3-butanediol (2,3-BDO), acrylic acid (AA), adipic acid (ADA), 1,2-propanediol (1,2-PDO), and 3-hydroxypropanoic acid (3-HP) in a sugarcane biorefinery, considering both current-best performances as well as possible technical improvements within the fundamental limits of strain and bioprocess development. A full-factorial design (FFD) was employed to generate potential alternative fermentation performances within achievable limits defined by flux balance analysis (FBA) and process design heuristics. Process simulations for various production scenarios were then developed using Aspen Plus® capturing each set of technical performance parameters. These assessments along with surface plot analysis translated the fermentation space between current and best-achievable performances into financial and environmental viability indicators. Results showed that at the current state of technology the direct microbial conversion of sugarcane molasses into 3-HP or 2,3-BDO was financially viable, with internal rates of return (IRR) of 45.7% and 26.6%, respectively. Additionally, 3-HP showed the least sensitivity to economic fluctuations, with a 100% probability of achieving an IRR above 40%, suggestive of strong economic robustness. Although the financial and environmental performances of 3-HP and 2,3-BDO can be improved through further technology development, such efforts should prioritize ADA in the medium-term, as it requires the least improvements in current technical performances to achieve cost-competitiveness with its fossil-based alternative. Biobased ADA also achieved the greatest reductions in GHG emissions, recording values 78%-81% lower than those of the fossil-based process. In the long-term, the feasible technical improvements in AA production showed the greatest financial benefit with a projected minimum selling price (MSP) that is 61.6% below its fossil-based equivalent, and highest environmental benefit, reducing GHG emissions by 84.5% below the fossil-based equivalent. However, biobased AA required the most substantial improvements in technical performances to achieve these targets, making its production via biobased 3-HP a more viable option in the medium-term. Biotechnological advancements in direct biobased processes improved both the financial and environmental performance, contributing to the industrial viability of all the products evaluated. However, owing to the high costs of R&D required to achieve these performances, there is a need to prioritize products with the highest theoretical yields and minimal gaps between current and required technical performance for process feasibility. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar. Doctoral 2026-01-09T10:15:12Z 2026-01-09T10:15:12Z 2025-12 Thesis https://scholar.sun.ac.za/handle/10019.1/134821 Stellenbosch University xx, 392 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Sugarcane industry -- Technological innovations Microbial biotechnology Biological products Strain theory (Chemistry) Sugarcane -- Propagation Fermentation Greenhouse gas mitigation Biomass conversion Sikazwe, Manasseh Kafula Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title | Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title_full | Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title_fullStr | Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title_full_unstemmed | Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title_short | Financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| title_sort | financial and environmental benefits from biotechnological developments toward feasible production of biochemicals in a sugarcane biorefinery via direct microbial conversions |
| topic | Sugarcane industry -- Technological innovations Microbial biotechnology Biological products Strain theory (Chemistry) Sugarcane -- Propagation Fermentation Greenhouse gas mitigation Biomass conversion |
| url | https://scholar.sun.ac.za/handle/10019.1/134821 |
| work_keys_str_mv | AT sikazwemanassehkafula financialandenvironmentalbenefitsfrombiotechnologicaldevelopmentstowardfeasibleproductionofbiochemicalsinasugarcanebiorefineryviadirectmicrobialconversions |