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New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar
Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2022.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2022
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| _version_ | 1867613464021696512 |
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| access_status_str | Open Access |
| author2 | Brink, Hendrik Gideon |
| author_browse | Brink, Hendrik Gideon |
| author_facet | Brink, Hendrik Gideon |
| collection | Thesis |
| dc_rights_str_mv | © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2022. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/86361 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:36:33.567Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/86361 New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar Brink, Hendrik Gideon u16278072@tuks.co.za Nicol, Willie Ronoh, Dominic Kibet Rhizopus delemar Rhizopus oryzae Malic acid Insoluble solids Whole-cell hydration Fumaric acid Immobilisation UCTD Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2022. Calcium carbonate has been extensively used as a neutralising agent in acid forming microbial processes. The effect of increasing calcium carbonate concentrations on Rhizopus delemar has not been previously investigated. In this study, an evaluation of fumaric acid (FA) and malic acid (MA) production was conducted at three CaCO3 concentrations in shake flask cultivations. Increased CaCO3 concentrations resulted in the co-production of FA and MA in the first 55 h of the fermentation (regime 1), and the subsequent depletion of FA thereafter (regime 2 ). Three factors were highlighted as likely causes of this response: insoluble solids, metal ion concentrations, and pH. Further shake flask cultivations as well as a continuous fermentation with immobilised R. delemar were used to explore the effect of the three factors on regime 1 and 2. Insoluble solids were found to have no effect on either the response in regime 1 or 2. Increasing the aqueous calcium ions concentrations to 10 g/L resulted in a three-fold increase in MA titres (regime 1 ). Moreover, an increase in pH above 7 was associated with the drop in FA concentrations in regime 2. Further tests established that this was due to the hydration of FA to MA, influenced by high pH conditions (7 or higher), nitrogen starvation and glucose depletion. Anaerobic conditions were also found to signi ficantly improve the hydration process. This study presents the fi rst investigation in which the production of FA followed by in situ hydration of FA to MA with R. delemar has been achieved. Chemical Engineering MEng (Chemical Engineering) Unrestricted 2022-07-21T06:34:44Z 2022-07-21T06:34:44Z 2022-09-07 2022 Dissertation * S2022 https://repository.up.ac.za/handle/2263/86361 https://doi.org/10.25403/UPresearchdata.19229979 en © 2022 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Rhizopus delemar Rhizopus oryzae Malic acid Insoluble solids Whole-cell hydration Fumaric acid Immobilisation UCTD New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title | New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title_full | New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title_fullStr | New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title_full_unstemmed | New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title_short | New insights into the role of pH, metal ions, and insoluble solids in the coproduction of fumarate and malate by Rhizopus delemar |
| title_sort | new insights into the role of ph metal ions and insoluble solids in the coproduction of fumarate and malate by rhizopus delemar |
| topic | Rhizopus delemar Rhizopus oryzae Malic acid Insoluble solids Whole-cell hydration Fumaric acid Immobilisation UCTD |
| url | https://repository.up.ac.za/handle/2263/86361 https://doi.org/10.25403/UPresearchdata.19229979 |