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Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613908373602304 |
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| access_status_str | Open Access |
| author | Lourens, Veronica |
| author2 | Van Rensburg, Eugene |
| author_browse | Lourens, Veronica Van Rensburg, Eugene |
| author_facet | Van Rensburg, Eugene Lourens, Veronica |
| author_sort | Lourens, Veronica |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/129082 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:43:37.288Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/129082 Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion Lourens, Veronica Van Rensburg, Eugene Görgens, Johann Ferdinand Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering. Process Engineering. Disk refining; deacetylation; single cell protein; microbial bioconversion; high solid loadings Sugarcane products Lignocellulose Single cell proteins Enzymatic digestion Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: Lignocellulosic biomass (LCB), as an abundant agro-processing residue, holds promise for addressing the challenges of waste and food security through its bioconversion to single-cell protein (SCP), offering an alternative protein source while minimising waste. However, the effective utilisation of LCB for SCP production requires the LCB to undergo pre-treatment to render the LCB fibre amenable to enzymatic digestion. This project addresses the challenges of utilising LCB for SCP production by investigating various pre-treatment strategies for enhancing the enzymatic digestibility of LCB for the purposes of SCP production through high-solids microbial bioconversion of pre-treated LCB using three selected microbes. The study found that disk refining and ball milling increased the digestibility of bagasse by an average of 4.30 g sugar/100 g DM. In contrast, the chemical pre-treatment method of deacetylation was found to significantly increase the digestibility of bagasse from 9.10 g sugar/100 g DM to a maximum of 75.74 g sugar/100 g DM (p < 0.05). Furthermore, the study found that combining deacetylation with disk refining (DDR) and ball-milling (DBM) significantly increased the digestibility of bagasse 8.8- and 5.6-fold, respectively, in comparison to untreated bagasse. Steam explosion, which served as a benchmark for pre-treatment efficiency, resulted in an enzymatic digestibility of 75.17 g sugar/100 g DM, indicating that deacetylation and DDR are suitable alternatives in comparison to this benchmark. The protein yields achieved from the microbial bioconversions of DDR and deacetylated bagasse were 2.47 ± 0.17 and 2.36 ± 0.2 g protein/100 g DM using Pleurotus ostreatus, and 3.29 ± 0.33 and 2.86 ± 0.21 g protein/100 g DM using Fusarium venenatum, respectively, indicating that DDR was the preferred pre-treatment strategy for protein production using fungal microorganisms. Furthermore, the study indicated that DDR had no substantial advantages for protein production from Saccharomyces cerevisiae, achieving protein yields of 1.91 ± 0.07 and 2.12 ± 0.15 g protein/100 g DM from the bioconversion of DDR and deacetylated bagasse, respectively. The optimal process conditions for protein production from these microorganisms were determined using 2 2 -factorial designs with solid and enzyme loadings as the independent variables. It was determined that the effects of the solid and enzyme loadings on the protein yields obtained from P. ostreatus and F. venenatum were more pronounced for DDR bagasse compared to deacetylated bagasse. Additionally, it was noted that changes in the solid loadings had consistently larger effects on the protein yields compared to those of the enzyme loadings, regardless of the microorganism used. Validation experiments of these factorial designs indicated consistent protein yields achieved for the replicate bioconversions using S. cerevisiae and F. venenatum, whereas the protein yields obtained from the replicate bioconversions of P. ostreatus varied by an average of 14.45 and 19.45% for deacetylated and DDR bagasse, respectively. The study thus identified F. venenatum as the most suitable option for protein production from the bioconversion of DDR bagasse using rotating drum bioreactors, achieving a maximum protein yield of 3.68 g protein/100 g DM at a solid and enzyme loading of 30% (w/w) and 16 FPU/g DM, respectively. AFRIKAANSE OPSOMMING: Lignosellulose-biomassa (LCB), as 'n ryk landbouverwerkingsoorskot, bied belofte om die uitdagings van afval en voedselsekuriteit aan te spreek deur bio-omskeping na enkelselproteïen (SCP), wat gelyktydig 'n alternatiewe proteïenbron bied terwyl afval geminimaliseer word. Die doeltreffende gebruik van LCB vir SCP-produksie vereis egter voorbehandeling om die LCBvesels vatbaar te maak vir ensiematiese verteerbaarheid. Hierdie projek spreek die uitdagings van die gebruik van LCB vir SCP-produksie aan deur ondersoek in te stel na verskeie voorbehandelingsstrategieë om die ensiematiese verteerbaarheid van LCB te verbeter vir die doeleindes van SCP-produksie deur hoë-soliede lading mikrobio-omskeping van voorbehandelde LCB met drie gekose mikroörganismes. Die studie het bevind dat diskverfyn en balvermaling die verteerbaarheid van bagasse met 'n gemiddelde van 4.30 g suiker/100 g droë gewig (DM) verhoog het. In teenstelling daarmee is daar bevind dat die chemiese voorbehandelingsmetode van deasetilasie die verteerbaarheid van bagasse aansienlik verhoog het van 9.10 g suiker/100 g DM tot 'n maksimum van 75.74 g suiker/100 g DM (p < 0.05). Verder het die studie bevind dat die kombinasie van deasetilasie met diskverfyn (DDR) en balvermaling (DBM) die verteerbaarheid van bagasse 8.8- en 5.6-voudig verhoog het, onderskeidelik, in vergelyking met onbehandelde bagasse. Stoomontploffing, wat as 'n maatstaf vir voorbehandeling doeltreffendheid gedien het, het gelei tot ensiematiese verteerbaarheid van 75.17 g suiker/100 g DM, wat aandui dat deasetilasie en DDR geskikte alternatiewe is in vergelyking met hierdie maatstaf. Die proteïenopbrengste wat bereik is uit die mikrobio-omskepings van DDR- en deasetileerde bagasse was 2.47 ± 0.17 en 2.36 ± 0.2 g proteïen/100 g DM met Pleurotus ostreatus, en 3.29 ± 0.33 en 2.86 ± 0.21 g proteïen/100 g DM met Fusarium venenatum, onderskeidelik. Dit dui daarop dat DDR die verkose voorbehandelingsstrategie was vir proteïenproduksie met swam mikroörganismes. Verder het die studie aangedui dat DDR geen noemenswaardige voordele vir proteïenproduksie uit Saccharomyces cerevisiae inhou nie, met proteïenopbrengste van 1.91 ± 0.07 en 2.12 ± 0.15 g proteïen/100 g DM uit die omskakeling van DDR- en deasetileerde bagasse, onderskeidelik. Die optimale prosesvoorwaardes vir proteïenproduksie uit hierdie mikroörganismes is bepaal deur 22 -faktoriale ontwerpe met soliedelading en ensiemlading as onafhanklike veranderlikes. Dit is bepaal dat die effekte van die soliedelading en ensiemlading op die proteïenopbrengste van P. ostreatus en F. venenatum meer uitgespreek was vir DDR-bagasse in vergelyking met deasetileerde bagasse. Daarbenewens is opgemerk dat veranderings in die soliedeladings konsekwent groter effekte op die proteïenopbrengste gehad het in vergelyking met dié van die ensiemlading, ongeag die mikroörganisme wat gebruik word. Valideringseksperimente van hierdie faktoriale ontwerpe het op dieselfde proteïenopbrengste vir die herhalende omskakelings van S. cerevisiae en F. venenatum gedui, terwyl die proteïenopbrengste van die herhalende omskakelings van P. ostreatus wisselend was met 'n gemiddelde van 14.45 en 19.45% vir deasetileerde en DDR-bagasse, onderskeidelik. Die studie het dus F. venenatum geïdentifiseer as die mees geskikte opsie vir proteïenproduksie uit die omskakeling van DDR-bagasse met roterende trombioreaktors, met 'n maksimum proteïenopbrengs van 3.68 g proteïen/100 g DM teen 'n soliede lading en ensiemdosering van 30% (w/w) en 16 FPU/g DW, onderskeidelik. Masters 2023-11-29T09:46:42Z 2024-01-08T21:45:06Z 2023-11-29T09:46:42Z 2024-01-08T21:45:06Z 2023-12 Thesis https://scholar.sun.ac.za/handle/10019.1/129082 en_ZA en_ZA Stellenbosch University xv, 105 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Disk refining; deacetylation; single cell protein; microbial bioconversion; high solid loadings Sugarcane products Lignocellulose Single cell proteins Enzymatic digestion Lourens, Veronica Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title | Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title_full | Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title_fullStr | Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title_full_unstemmed | Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title_short | Pre-treatment of sugarcane bagasse for conversion to single cell protein through one-step enzymatic hydrolysis and bioconversion |
| title_sort | pre treatment of sugarcane bagasse for conversion to single cell protein through one step enzymatic hydrolysis and bioconversion |
| topic | Disk refining; deacetylation; single cell protein; microbial bioconversion; high solid loadings Sugarcane products Lignocellulose Single cell proteins Enzymatic digestion |
| url | https://scholar.sun.ac.za/handle/10019.1/129082 |
| work_keys_str_mv | AT lourensveronica pretreatmentofsugarcanebagasseforconversiontosinglecellproteinthroughonestepenzymatichydrolysisandbioconversion |