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Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG
Thesis (MEng)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867613914474217472 |
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| access_status_str | Open Access |
| author | Mabutyana, Luntu |
| author2 | Pott, Robert William M. |
| author_browse | Mabutyana, Luntu Pott, Robert William M. |
| author_facet | Pott, Robert William M. Mabutyana, Luntu |
| author_sort | Mabutyana, Luntu |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123936 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:43.080Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/123936 Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG Mabutyana, Luntu Pott, Robert William M. Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering. Photofermentation UCTD Biohydrometallurgy Phenolics -- Metabolism Rhodopseudomonas Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The current study aimed to investigate photo-fermentative biohydrogen gas production potential of Rhodopseudomonas palustris CGA009 by utilising the liquid hydrolysate of brewers spent grain (BSG), pre-treated by steam explosion. Eight pure phenolic compounds present in the BSG hydrolysate were individually tested under anaerobic conditions followed by photo-fermentation of BSG hydrolysate under anaerobic conditions at 5, 10, 15 and 20% concentrations. To investigate the potential for the use of photo-fermentation as a pre-treatment step in bioethanol fermentation the tolerance of R. palustris towards ethanol inhibition was tested at concentration range of 0.25 – 14% (v/v) under anaerobic photo-fermentative conditions. Hydroxymethoxyfurfural (HMF) and furfural, also present in hydrolysate, were tested at 0.096 – 1.929 g/L and 0.05 – 2 g/L, respectively. Results showed that among the eight phenolic compounds tested, the effect on R. palustris cell growth was insignificant in most of the compounds except vanillin, syringic and vanillic acid. The effect on hydrogen production only showed mild enhancement by syringaldehyde which accumulated total hydrogen of 156 ± 20 mL/L whereas other compounds showed only a decrease, with vanillin solution obtaining the lowest accumulated total hydrogen of 136 ± 0 mL/L. Increasing ethanol concentrations reduced hydrogen production and cell growth even at low concentrations. Hydrogen production and cell growth in furfural was observed in concentration range 0.05 - 0.25 g/L but was absent at 0.5 - 1.8 g/L. Cell growth was observed for HMF concentration range 0.096 - 0.965 g/L but was severely inhibited at 1.929 g/L, therefore the MIC of HMF on R. palustris cell growth under the tested conditions is between 0.965 - 0.965 g/L concentration range. Hydrogen production occurred on HMF medium solution but was irregular among replicates. The inability to consume glucose and xylose shows potential for use as a detoxification agent in sugar rich lignocellulose hydrolysates for integrated biofuel production. Maximum cell growth of R. palustris in photo-fermented BSG was obtained at 20 % liquid hydrolysate concentration, and this indicates that minimum inhibitory concentration is above 20 % concentration value. The mixed content of phenolic compounds in BSG hydrolysate was consumed, as supported by consumption of individual phenolic compounds. Highest COD removal efficiency was 60.1 % in 5 % concentration, but the highest COD content removal was 5.99 g/L in 20 % concentration. Maximum hydrogen production was obtained in 5 % concentration with 15 ± 2.8 mL/L, followed by 15 % concentration with 12 ± 1.8 mL/L. The project successfully demonstrated that R. palustris can produce hydrogen by photo- fermentation in the presence of potentially inhibitory compounds, which are commonly toxic to various organisms. Co-culture production of ethanol is not recommended since low ethanol concentrations inhibited growth. This work builds significantly on the little information there is in the literature on photo-fermentation of potentially inhibitory compounds, and on developing integrated biorefinery processes for biofuel production. AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar Masters 2021-12-06T10:54:47Z 2021-12-22T14:30:08Z 2021-12-06T10:54:47Z 2021-12-22T14:30:08Z 2021-12 Thesis http://hdl.handle.net/10019.1/123936 en_ZA Stellenbosch University 104 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Photofermentation UCTD Biohydrometallurgy Phenolics -- Metabolism Rhodopseudomonas Mabutyana, Luntu Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title | Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title_full | Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title_fullStr | Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title_full_unstemmed | Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title_short | Biohydrogen production potential of R. palustris CGA009 by photofermentation of liquid hydrolysate obtained from steam explosion of BSG |
| title_sort | biohydrogen production potential of r palustris cga009 by photofermentation of liquid hydrolysate obtained from steam explosion of bsg |
| topic | Photofermentation UCTD Biohydrometallurgy Phenolics -- Metabolism Rhodopseudomonas |
| url | http://hdl.handle.net/10019.1/123936 |
| work_keys_str_mv | AT mabutyanaluntu biohydrogenproductionpotentialofrpalustriscga009byphotofermentationofliquidhydrolysateobtainedfromsteamexplosionofbsg |